Spatial Layout of Cotton Seed Production Based on Hierarchical Classiﬁcation: a Case Study in Xinjiang, China

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Article Spatial Layout of Cotton Seed Production Based on Hierarchical Classiﬁcation: A Case Study in Xinjiang, China

Yingnan Niu 1,2, Gaodi Xie 1,2,*, Yu Xiao 1,2, Keyu Qin 1, Jingya Liu 1, Yangyang Wang 1,2, Shuang Gan 1, Mengdong Huang 1,2, Jia Liu 1,2, Caixia Zhang 1 and Changshun Zhang 1

1 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, A11 Datun Road, Chaoyang District, Beijing 100101, China; [email protected] (Y.N.); [email protected] (Y.X.); [email protected] (K.Q.); [email protected] (J.L.); [email protected] (Y.W.); [email protected] (S.G.); [email protected] (M.H.); [email protected] (J.L.); [email protected] (C.Z.); [email protected] (C.Z.) 2 College of Resources and Environment, University of the Chinese Academy of Sciences, 19 A Yuquan Road, No.19, Shijingshan District, Beijing 100049, China * Correspondence: [email protected]

Abstract: Cotton seed production is the main form of agriculture in Xinjiang, China. Unreasonable distribution of cotton seed production results in a waste of water, land, and human resources. In this study, we established a hierarchical classification integrating method; investigated the spatial suitability of climate, land and water resources, and infrastructure; examined the production risk and planting history; and integrated spatial suitability and production risk and history to produce the spatial layout of seed production for early-maturing cotton (EMC), early–medium-maturing cotton (EMMC), and long staple cotton (LSC) in Xinjiang. The results indicated that the appropriate areas Citation: Niu, Y.; Xie, G.; Xiao, Y.; for EMC, EMMC, and LSC seed production are 6.4 × 105, 5.5 × 105, and 3.6 × 105 ha, respectively. Qin, K.; Liu, J.; Wang, Y.; Gan, S.; By combining the suitable areas of seed production for the three cotton species, we concluded that Huang, M.; Liu, J.; Zhang, C.; et al. the superior and most suitable area for producing cotton seed of EMC, EMMC, or LSC is located Spatial Layout of Cotton Seed in the western Tarim Basin. The sub-suitable area for cotton seed production of EMC, EMMC, or Production Based on Hierarchical LSC is mostly distributed in the western and northern Tarim Basin. This research provides a good Classification: A Case Study in Xinjiang, China. Agriculture 2021, 11, solution to the selection of cotton seed production base; however, adoption will depend on the actual 759. https://doi.org/10.3390/ preference and market factors. agriculture11080759 Keywords: cotton seed production base; spatial suitability; hierarchical classification Academic Editor: Bernard Hauser

Received: 26 July 2021 Accepted: 8 August 2021 1. Introduction Published: 10 August 2021 Cotton, an important source of natural fibers to textile industries around the world, is widely planted in more than 70 countries [1,2]. As a key constituent of cotton production Publisher’s Note: MDPI stays neutral and raw cotton consumption in the world, China accounts for one-quarter of the world’s with regard to jurisdictional claims in cotton output and one-third of the world’s cotton consumption [3], and the quantity and published maps and institutional affil- quality of China’s cotton production will have a significant impact on the global cotton iations. industry. Due to sufficient light, abundant heat, suitable soil, and water conditions, the breeding of new cotton varieties with high yield and insect resistance, advanced water- saving irrigation technology, and related policies, Xinjiang, with a long history of cotton planting, has become the center of cotton planting in China, contributing nearly 84% of Copyright: © 2021 by the authors. the total production in China in 2018 [4,5]. Compared with 2017, the cotton area in 2018 Licensee MDPI, Basel, Switzerland. increased by 210,300 ha, the annual planting area remained at 2.4 to 2.667 million hectares, This article is an open access article and the annual cotton seed demand was between 80,000 and 100,000 tons [6]. In regard distributed under the terms and to whether Xinjiang can continue to play its key role in the industry of cotton in the conditions of the Creative Commons future, the development of the cotton seed industry is particularly important. The regional Attribution (CC BY) license (https:// distribution optimization of cotton seed production based on regional resources is essential creativecommons.org/licenses/by/ to the development of the seed industry in Xinjiang [7]. 4.0/).

Agriculture 2021, 11, 759. https://doi.org/10.3390/agriculture11080759 https://www.mdpi.com/journal/agriculture Agriculture 2021, 11, 759 2 of 23

One of the most important questions faced by the cotton seed industry is cotton seed production. Compared with the seed production of other crops, cotton production has a wide range and large quantity of good propagation, numerous connections, and relatively heavy management tasks. Therefore, cotton seed production must be guar- anteed by a sound seed breeding system. The breeding mode in the cotton seed industry in Xinjiang is mainly entrusted breeding, that is, the “company–base–cotton farmer breeding” mode, which most private seed enterprises depend on. Moreover, some seed companies have their own good breeding system with a certain scale of good breeding fields, such as the Tahe seed industry, Jinfengyuan seed industry, and Qianhai seed industry [6]. Regardless of the kind of cotton seed breeding system, the most basic re- quirement is to identify the suitable cotton seed breeding field. The chosen seed breeding field is closely related to local climate, water and soil resources, production risk, and socioeconomic conditions. The planting window for cotton in Xinjiang typically ranges from April to May, and harvest ranges from September to October. Climate is the prominent factor of cotton growth and development. Temperature is the critical controller of different cotton development events. Reported cardinal temperatures for cotton growth and development are in the range of 12 to 15 ◦C for the minimum temperature and 20 to 35 ◦C for the optimum temperature [2,8–10]. Low temperature (<12 ◦C) in the early stage of cotton growth leads to delayed growth and biomass accumulation and development, while short-term high temperature (>35 ◦C) in the middle stage of growth can have a detrimental effect on the fertilization rate, cotton boll volume, boll weight, the quantity of cottonseed buds that fall off, and fiber quality, resulting in reduced water use efficiency and yield [2,10–19]. In addition, cotton production is closely related to heat, and the heat condition in the growing season is closely related to cotton quality; the lack of heat in the growing season also has a great impact on cotton yield. Active accumulated temperature equal to or greater than 10 ◦C (AAE_10) and the frost-free period (FFP) are the basic heat conditions for cotton growth [20]. With the increase in heat, the sowing and emergence periods of cotton significantly advance, the stopping of growth is delayed, and the whole growth period of cotton is prolonged, which is conducive to the improvement of cotton yield and quality. Water plays an important role in the processes of cotton production [21]. Precipitation is an important determinant of cotton growth [22]. In the crop growth season, especially in the critical period of crop water demand, timely and appropriate precipitation is undoubtedly conducive to the normal growth and development of crops, reducing agricultural investment and striving for high yield and quality. However, under natural conditions, atmospheric precipitation is always uneven, and soil moisture is often insufficient or in surplus. Some scholars [10,23] found that increased precipitation was beneficial to cotton yield in Northwest China. Studies have shown that uneven spatiotemporal distribution of precipitation may adversely affect cotton yield [24]. The cotton planting system in Xinjiang is operated on a “one crop per year” basis. In this region, almost all cotton fields depend on irrigation, and natural precipitation is not very important for cotton production [25]. Light is the only energy source for plant photosynthesis. A decrease in light intensity reduces photosynthetic production, limits organic nutrient supply to the reproductive organs, and, finally, increases the rate of fruit shedding, the effects of which impact cotton yield [12,26]. Soil, as a natural resource and which can play a significant role in the agricultural production and productivity [27], is an important foundation for cotton seed production. The selection of cotton planting should be in sandy loam soil, which is convenient for machine farming and irrigation [28]. The suitable soil layer thickness for cotton growth is more than 30 cm, as it allows cotton to be free from wind and sand attack in late spring [29]. Cotton is suitable for growing in soil with good ventilation and drainage and a deep and fertile soil layer. The suitable soil pH is 6.5 to 8.0. When the pH value of soil exceeds the optimum range, the plant growth is hindered, and the development is slow. Agriculture 2021, 11, 759 3 of 23

Moreover, Xinjiang is the first cotton area in China to establish an information system of soil nutrient management and efficient fertilization [30]. The risk of cotton production is another key factor that must be considered in de- termining the distribution of cotton seed production. Xinjiang has been implementing technical measures of integrated pest control for a long time, and its experience and technology of pest control are acknowledged on a national scale. The ecological conditions of the cotton field are good, and the number of beneficial organisms is large, which is conducive to the protection of benefits and control of pests. The climate in the Xinjiang cotton region is dry, and the temperature is low in winter, which is not conducive to the overwintering propagation of diseases and insect pests [30]. However, with the expansion of the cotton field area and the change in crop structure, disease and insect pests tend to be aggravated. Wilt and verticillium wilt are developing rapidly. Cotton bollworm and cotton leaf curl virus have already broken out in some cotton areas. We should pay attention to the potential threat of diseases and insect pests to cotton production [31]. Regional cotton yield is closely related to regional selection of cotton seed production. High-cotton-yield regions should prioritize cotton seed production. In addition, cotton seed production enterprises are an important part of the development of the cotton seed industry. There are more than 800 cotton seed industries at different levels in Xinjiang [6], which provides an important foundation for cotton seed production in Xinjiang. Convenient transportation is also a booster of the seed industry development, as they ensure that cotton seeds can be transported to the sale area in time. Previous studies on cotton production have mainly focused on the analysis of spatial and temporal changes in cotton yield and cotton planting areas based on statistical data. Ma [3] investigated the spatiotemporal changes and gravity center migration path in cotton production, the area, and the yield in China by methods of a time-series trend and spatial analysis. Yu [32] analyzed the spatial distribution and influencing factors of cotton production layout in Xinjiang under the background of supply side reform. Some studies have analyzed the relationship between the quality or quantity of cotton and influencing factors. Mc Michael [24] studied the response of cotton to water deficits through a field investigation. Doma [22] stimulated the impacts of climate change on cotton production in the Mississippi Delta. Reddy [2] and Liakatas [16] analyzed the effects of temperature on cotton seedling emergence, growth, and development and fiber properties. There have been relatively few studies on cotton production layout. However, compared with the selection of the cotton planting area, the selection requirements of the cotton seed production base are much more stringent, and, to the best of our knowledge, few studies have examined the spatial layout of the cotton seed production base. Therefore, our aim was to identify the cotton seed production base in Xinjiang. Specifically, we intended to investigate the spatial distribution of climate, land and water resources, infrastructure, production risk, and planting history and to develop the spatial layout of seed production for early-maturing cotton (EMC), early–medium-maturing cotton (EMMC), and long staple cotton (LSC) in Xinjiang, using the hierarchical classification integrating method. Consequently, this study provides insights into integrating multi-source spatial data of climatic conditions, soil and water resources, production risks, and socioeconomic factors for optimizing the distribution of cotton or even the seed production of other crops.

2. Materials and Methods 2.1. Study Area Xinjiang Uygur Autonomous Region (Xinjiang, 73◦400~96◦180 E, 34◦250~48◦100 N) (Figure1), the largest provincial administrative area, with a total area of one-sixth of China’s land area, is located toward the northwest border of China. The northern part of this study area was the Altai Mountains, and the south part was the Kunlun Mountains. The Tianshan Mountains lie in the central part of Xinjiang, dividing Xinjiang into the Tarim Basin in the south and the Junggar Basin in the north. This region is characterized by a temperate continental climate with a large daily temperature range and rare annual Agriculture 2021, 11, x FOR PEER REVIEW 4 of 22

Agriculture 2021, 11, 759 4 of 23 Basin in the south and the Junggar Basin in the north. This region is characterized by a temperate continental climate with a large daily temperature range and rare annual precipitation.precipitation. The The dominant dominant crops crops in inthe the farming farming systems systems are are wheat, wheat, corn, corn, cotton, cotton, beetroots, beetroots, vegetables,vegetables, and melon. The The cotton cotton production production area in Xinjiang is mainly mainly divided divided into three three subsub areas, which areare thethe northernnorthern cotton cotton area, area suitable, suitable for for producing producing early-maturing early-maturing cotton; cotton;the southernthe southern cotton cotton area, area, suitable suitable for for early–medium-maturing early–medium-maturing cotton; cotton; andand thethe eastern cottoncotton area, area, most most suitable for long staple cotton [30]. [30]. According to the Xinjiang statistical yearbook,yearbook, Xinjiang’s cotton output reached 4,566,000 tons in 2018.

FigureFigure 1. Study area area and and spatial spatial distribution distribution of cotton seed of cotton production seed enterprises production and cultivated enterprises land. and cultivated land. 2.2. Data Collection and Processing 2.2. DataThe Collection dataset used and Processing in this study mainly included meteorological data, soil and water resourceThe data,dataset and used statistical in this data. study Based mainly on theincluded literature, meteorological expert knowledge, data, soil and and the actualwater situation in Xinjiang, we obtained the key indicators and threshold values of cotton seed resource data, and statistical data. Based on the literature, expert knowledge, and the ac- production in the area. In addition, the climate index, the soil and water conditions, the tual situation in Xinjiang, we obtained the key indicators and threshold values of cotton socioeconomic conditions, and the production risk conditions of the three types of cotton seed production in the area. In addition, the climate index, the soil and water conditions, in the study area were divided into the same criteria (Table1). the socioeconomic conditions, and the production risk conditions of the three types of cotton2.2.1. Meteorologicalin the study area Data were divided into the same criteria (Table 1). The average daily temperature from 1980 to 2018 was extracted to calculate the active 2.2.1. Meteorological Data accumulated temperature equal to or greater than 10 ◦C (AAE_10) (Formula (1)), the activeThe accumulated average daily temperature temperature greater from than1980 to 15 2018◦C (AAE_15) was extracted (Formula to calculate (2)), the the average active accumulatedtemperature intemperature July and August equal to (AT_JA), or greater and than the duration10 °C (AAE_10) in days (Formula of temperature (1)), the equal active to accumulatedor greater than temperature 15 ◦C (DD_15) greater (Formulas than 15 °C (3)–(5)). (AAE_15) The daily(Formula minimum (2)), the temperature average temper- from ature1980 toin 2018July wasand usedAugust to calculate(AT_JA), theand frost-free the duration period in(FFP). days of Taking temperature the daily equal minimum to or greatertemperature than 15 equal °C (DD_15) to or greater (Formulas than 2 (3)–(5)).◦C as the The index daily of minimum frost days, temperature the duration from between 1980 tothe 2018 last was frost used day to and calculate the ﬁrst the frost frost-free day is period the frost-free (FFP). Taking period, the and daily the minimum calculation tem- of peratureﬁrst and equal last frost to or days greater is thethan same 2 °C asas Dthstarte indexand of D endfrostof days, DD_15. the duration The maximum between daily the lasttemperature frost day fromand the 1980 first to frost 2018 day was is used the fros to calculatet-free period, the duration and the incalculation days of temperature of first and ◦ lastequal frost to days or greater is the thansame 35 as DCstart (DD_35), and Dend and of DD_15. the method The maximum was same daily as that temperature of DD_15. fromSunshine 1980 hoursto 2018 from was 1980 used to to 2018 calculate were usedthe duration to calculate in days the sunshineof temperature rate from equal April to or to greaterOctober than (SR_AO) 35 °C and(DD_35), annual and sunshine the method hours was (ASH). same Daily as that precipitation of DD_15. from Sunshine 1980 to hours 2018 was used to calculate precipitation from September to October (Pre_SO).

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The inverse distance weighted (IDW) method was adopted to interpolate AAE_10, AAE_15, AT_JA, DD_15, FFP, DD_35, SR_AO, ASH, and Pre_SO into a raster surface at 30-m spatial resolution. Then, according to the threshold value given in Table1, the grid of AAE_10, AAE_15, AT_JA, DD_15, FFP, DD_35, SR_AO, ASH, and Pre_SO were reclassiﬁed to obtain the suitable and the unsuitable area of each index. Active accumulated temperature

n AAE_10 = ∑ Ti i=1 (1)

where n is days of the cotton growing period. Suppose T is the average daily temperature; when T is less than 10, Ti is equal to 0; otherwise, Ti is equal to T.

n AAE_15 = ∑ Ti (2) i=1

where n is days of the cotton growing period. Suppose T is average daily temperature; when T is equal or less than 15, Ti is equal to 0; otherwise, Ti is equal to T. Duration in days of temperature equal to or greater than 15 centigrade (DD_15) This calculation was divided into two steps: the calculation of the start time and the calculation of the end time. Start time. Taking the cotton growing period as an example, first, the date (i) when the average daily temperature first exceeded or was equal to 15 ◦C had to be identified. Second, the five-day moving average temperature (Ti−4, i ≥ 5) was calculated by pushing forward four days (Formula (3)). Then, the first five-day moving average temperature of 15 ◦C or above was selected from the longest five-day moving average temperature sequence of 15 ◦C or more in the growing period. Thirdly, from the five days that make up the five-day moving average temperature (T15), the first day (Dstart) when the daily average ◦ temperature exceeded or was equal to 15 C was selected, and Dstart was the starting time of the stable period passing through 15 ◦C.

(ti−4 + ti−3 + ti−2 + ti−1 + ti) T − = (3) i 4 5 End time. During the cotton growing period, the date (j) when the daily average temperature first appeared to be less than 15 ◦C was identified from the daily average temperature. Then, the five-day moving average temperature (Tj−4, j ≥ 5) was calculated by pushing forward four days (Formula (4)). Following this, the last five-day moving ◦ average temperature equal to or greater than 15 C(Tm−4, m ≥ 6) was selected. Finally, ◦ the last day (Dend) with an average daily temperature greater than or equal to 15 C was selected from the five days constituting Tm−4. tj−4 + tj−3 + tj−2 + tj−1 + tj T − = (4) j 4 5

DD_15 = Dend − Dstart + 1 (5)

2.2.2. Soil and Water Resource Data Based on the MODIS vegetation index data of 250 m resolution in 2005, the cultivated land distribution was obtained by human–computer interactive interpretation and analysis [33]. A Chinese soil dataset based on the world soil database (hwsd) (v1.1) was applied to extract soil texture (ST), soil depth (SD), and soil PH (S_PH) values. Drainage density (DD) was obtained based on the river distribution data. The average annual total amount of water resources per unit area (TAW) was calculated based on the runoff yield modulus of the secondary basin from 2010 to 2016. Then, according to the threshold of Agriculture 2021, 11, 759 6 of 23

indexes, ST, SD, S_PH, DD, and TAW were resampled to the raster surface at 30-m spatial resolution and reclassiﬁed into suitable and unsuitable areas for the identiﬁcation of cotton seed production bases.

2.2.3. Production Risk The frequency of meteorological disasters (FMD) was calculated based on meteorological disasters from 2000 to 2011. The frequency of pest diseases (FPD) was calculated based on pest risk from 2000 to 2011. The mean Kendall method [34] was applied to calculate the precipitation change rate (PCR) by using precipitation from 1950 to 2018. The average cotton yield reduction rate [35] over the years (AYR) was calculated from the cotton yield. FMD, FPD, and PCR were interpolated into raster surfaces at a 30-m spatial resolution based on the IDW method, and AYR was converted into raster surfaces at a 30-m spatial resolution. FMD and FPD were both divided into two classes of high and low by using the natural breaks (Jenks) method, with low indicating better identification of cotton seed production bases. In addition, PCR and AYR were reclassified into large and small, where small meant good cotton seed production base identification.

2.2.4. Socioeconomic Data County-level cotton yield from 2015 to 2017 was used to calculate the annual cotton yield (ACY). Road density (RD) was calculated based on distribution data using linear density analysis. The density of cotton seed production enterprises (DCE) and the accessibility of farmland to seed production enterprises (AFE) were calculated from the distribution of cotton seed production enterprises by using point density and Euclidean distance methods in ArcGIS. There were two steps to obtain the data of cotton seed production enterprises. Firstly, based on the Baidu map, the seed companies in the research area were obtained by using “seed industry company” as the search keyword. Secondly, the cotton seed production companies were screened out. Then, the longitude and latitude coordinates of cotton seed production companies were obtained based on the Baidu map picking coordinate system, and the distribution points of seed production companies were obtained by im- porting them into the geographic database. ACY, RD, DCE, and AFE from the above were required to be converted into a raster surface at 30-m spatial resolution. The natural breaks (Jenks) method was applied to reclassify ACY, RD, and AFE into high–low, high–low, and easy–difﬁcult, respectively, where high and easy indicated superior selection of cotton seed production bases. DCE was divided into greater than 0 and equal to 0, where greater than 0 represented a suitable cotton seed production base.

2.2.5. Production History Currently, there are cotton seed production bases in the Aksu region, Bayingol Mon- golian Autonomous Prefecture, Bortala Mongolian Autonomous Prefecture, the Kashi region, and the Tacheng region. We believe that as long as the construction of seed production bases (SDB) is carried out, they will be suitable areas for planting in terms of production history. Agriculture 2021, 11, 759 7 of 23

Table 1. Indicators for cotton seed production of three cotton varieties based on a literature survey and expert knowledge.

Indicators EMC EMMC LSC Data Time AAE_10 (◦C) [28] >3500 >3800 >4000 AAE_15 (◦C) [36] – >3000 – Average daily temperature 1 AT_JA (◦C) [28] 20–30 20–30 20–30 DD_15 (day) [28] – >155 – Meteorological data FFP (day) [28] >170 >180 – Daily minimum temperature 1 1980–2018 DD_35 (day) ≤10 ≤10 ≤10 Daily maximum temperature 1

SR_AO [28] 60–70% 60–70% 60–70% 1 ASH (hours) [28,36] ≥2700 ≥2700 ≥2700 Sunshine hours Pre_SO (mm) <27.47 <27.47 <27.47 Precipitation 1 Slope <5 <5 <5 Slope 2 – sandy sandy sandy ST loam loam loam Soil and water 3 – SD (cm) [29] >30 >30 >30 CS_WSD S_PH 6.5–8 6.5–8 6.5–8 DD >0 >0 >0 River 4 – TAW >0 >0 >0 RYM 5 2010–2016 ACY High High High County-level cotton yield 6 2015–2017 RD High High High Road 7 – Socioeconomic data DCE High High High 8 – AFE Easy Easy Easy DSE FMD Low Low Low Meteorological disasters 9 2000–2011 FPD Low Low Low Pest risk 9 Production risk PCR Small Small Small Precipitation 9 1950–2018 AYR Small Small Small Cotton yield 10 1988–2017 Production history SDB YES YES YES Seed production area 11 – (Note: EMC: early-maturing cotton; EMMC: early–medium-maturing cotton, LSC: long staple cotton. CS_WSD: Chinese soil dataset based on the world soil database (hwsd) (v1.1); DSE: distribution of cotton seed production enterprises; RYM: runoff yield modulus of the secondary basin. 1 http://data.cma.cn/, accessed on 9 February, 2021 2 http://www.resdc.cn/, accessed on 12 February, 2021; 3 http://www.crensed.ac.cn/, accessed on 9 February, 2021; 4 https://www.openstreetmap.org/, accessed on 5 February, 2021; 5 http: //slt.xinjiang.gov.cn/, accessed on 10 February, 2021; 6 Statistical yearbook of the Xinjiang Uygur Autonomous Region; 7 https://www. openstreetmap.org/, accessed on 5 February, 2021; 8 big data platform for the seed industry and Baidu map; 9 http://data.cma.cn/, accessed on 9 February, 2021; 10 Statistical yearbook of the Xinjiang Uygur Autonomous Region; 11 Department of Agriculture and Rural Affairs of Xinjiang).

2.3. Methodology Based on the hierarchical classiﬁcation, the identiﬁcation of three kinds of cotton seed production bases was mainly divided into the following steps (Figure2): Step 1: according to the climatic suitability indexes of cotton seed production, the climate suitability of Xinjiang was calculated, and then, the whole region was divided into a suitable climate area and an unsuitable climate area. Step 2: based on suitability indexes of water and soil conditions for cotton seed production, the suitable climate area obtained in step 1 was divided into a suitable water and soil (W&S) and an unsuitable W&S area. Step 3: on the basis of suitability indexes of production risk (PR), the suitable W&S area was divided into a low-risk production area and a high-risk production area. Step 4: on account of the social–economic (SE) suitability indexes of cotton seed production, the SE suitability of seed production was calculated in the low-risk production area obtained in Step 3, and the low- risk production area was subdivided into a suitable SE and an unsuitable SE area. Step 5: the suitable SE area was divided into a superior production area and a suitable production area based on the historical situation of cotton seed production. Step 6: the unsuitable climate area, unsuitable W&S area, and high-risk production area, which were generated in Steps 1, 2, and 3, were grouped into the unsuitable production area. The unsuitable SE area was categorized as the sub-suitable production area. Step 7: the superior production area, suitable production area, sub-suitable production area, and unsuitable production area were overlaid with cultivated land to obtain the spatial division of cotton seed production Agriculture 2021, 11, x FOR PEER REVIEW 8 of 22

in Steps 1, 2, and 3, were grouped into the unsuitable production area. The unsuitable SE Agriculture 2021, 11, 759 8 of 23 area was categorized as the sub-suitable production area. Step 7: the superior production area, suitable production area, sub-suitable production area, and unsuitable production area were overlaid with cultivated land to obtain the spatial division of cotton seed pro- induction Xinjiang. in Xinjiang. Finally, consideringFinally, considering the fact the that fact the that seed the production seed production base needs base to needs have to a certainhave a certain scale, the scale, results the obtainedresults obtained in Step 7in were Step screened 7 were screened according according to the standard to the standard of more thanof more 100 than mu (about 100 mu 6.66 (about hectare), 6.66 and, hectare), ﬁnally, and, the finally, suitability the distributionsuitability distribution of the cotton of seed the productioncotton seed baseproduction in the study base in area the was study obtained. area was obtained.

All area

N Climatic suitability Y Climate suitable area Climate unsuitable area

N W&S suitability Y W&S suitable area W&S unsuitable area

PR N suitability Y High risk production area Low risk production area

SE N suitability Y SE unsuitable area SE suitable area

Production N history

Y Superior production Suitable production Sub-suitable Unsuitable areas area production area production area

Cultivated land

>6.66 ha

Cotton seed production base

Figure 2. Diagram of methodological framework for the analysis of cotton seed production suitability basedFigure on 2. hierarchicalDiagram of classiﬁcation,methodological where framework W&S, PR, for and the SEanalysis stand of for cotton water seed and soil,production production suitabil- risk, andity based social–economic, on hierarchical respectively. classification, (Y indicates where W&S, yes; NPR, indicates and SE stan no).d for water and soil, production risk, and social–economic, respectively. (Y indicates yes; N indicates no). As a region may be suitable for different varieties of cotton seed production, in this study,As we a integratedregion may the be abovesuitable results for different of different varieties varieties of cotton of cotton seed seed production, production in intothis thestudy, suitability we integrated zones to the determine above results the comprehensive of different varieties cotton of seed cotton production seed production suitability into in thethe studysuitability area; zones the method to determine is shown the in comprehe Figure3. Thensive suitability cotton seed judgment production of comprehensive suitability in seedthe study production area; the in Region_method is x wasshown taken in Figure as an example. 3. The suitability As shown judgment in Figure of3a, comprehen- Region_ x maysive seed be suitable production for three in Region_ cotton varieties x was taken for seed as an production example. here, As shown and each in Figure cotton variety3a, Re- may have three different degrees of suitability for seed production; thus, there will be 27 gion_ x may be suitable for three cotton varieties for seed production here, and each cotton possibilities (Figure3b) in the study area, which can be observed in Figure3a. In each variety may have three different degrees of suitability for seed production; thus, there will possibility, when, and only when, example 1 appears once, the cotton variety represented be 27 possibilities (Figure 3b) in the study area, which can be observed in Figure 3a. In by example 1 is selected for the seed production scheme of the group; when, and only when, each possibility, when, and only when, example 1 appears once, the cotton variety example 1 appears twice, the two cotton varieties represented by example 1 are selected in the seed production scheme of the group; and when example 1 appears three times, it means that any one of the three cotton varieties can be selected for cotton seed production. On the basis of the above judgment, if example 2 appears in a certain possibility, the cotton

varieties represented by example 2 are selected for seed production; if example 2 appears Agriculture 2021, 11, x FOR PEER REVIEW 9 of 22

represented by example 1 is selected for the seed production scheme of the group; when, and only when, example 1 appears twice, the two cotton varieties represented by example 1 are selected in the seed production scheme of the group; and when example 1 appears three times, it means that any one of the three cotton varieties can be selected for cotton seed production. On the basis of the above judgment, if example 2 appears in a certain possibility, the cotton varieties represented by example 2 are selected for seed production; if example 2 appears twice, the two cotton varieties represented by example 2 are selected for seed production; if there are three instances of example 2, any one of the three cotton Agriculture 2021, 11, 759 9 of 23 varieties can be selected for seed production. Finally, if example 3 appears three times in the combination, it means that any one of the three cotton varieties represented by example 3 can be selected for seed production. twice,For the example, two cotton in the varieties possibility represented of 1a2b2c, by exampleRegion_x 2 is are suitable selected for for three seed kinds production; of cotton if seedthere production. are three instances However, of example Region_x 2, is any supe onerior of thefor threeearly-maturing cotton varieties cotton can seed be produc- selected tionfor seed and production.suitable for early–medium-maturing Finally, if example 3 appears cotton three and times long in staple the combination, cotton seed itproduc- means tion.that anyHence, one considering of the three the cotton most varieties suitable represented factor, the seed by example production 3 can scheme be selected selected for hereseed is production. early-maturing cotton seed production.

Figure 3. Solutions to the dilemma of the areaarea forfor differentdifferent kindskinds ofof cottoncotton seed seed production production at at the the same same time, time, (a ()a Region_) Region_ x xmay may be be suitable suitable for for three three cotton cotton varieties variet fories seedfor seed production production here, here, and each and cottoneach cotton variety variety may have may three have different three different degrees degreesof suitability of suitability for seed productionfor seed production and (b) 27 and possibilities (b) 27 possibilities can be observed. can be observed. (note, 1: superior, (note, 1: 2:superior, suitable, 2: 3: suitable, sub-suitable, 3: sub- a: suitable, a: early-maturing cotton, b: early–medium-maturing cotton, c: long staple cotton, and 1a: superior cotton seed early-maturing cotton, b: early–medium-maturing cotton, c: long staple cotton, and 1a: superior cotton seed production production area for early-maturing cotton). area for early-maturing cotton).

3. ResultsFor example, in the possibility of 1a2b2c, Region_x is suitable for three kinds of cotton 3.1.seed Suitable production. Climate However, Area for Region_xCotton Seed is superiorProduction for early-maturing cotton seed production and suitableAmong the for influencing early–medium-maturing factors of climate cotton suitability and long for staple early-maturing cotton seed cotton production. (EMC) seedHence, production, considering the the suitable most suitableAAE_10 factor,areas were the seed distributed production in southern, scheme selected northern, here and is easternearly-maturing Xinjiang, cotton and among seed production. them, the suitable areas were larger in southern Xinjiang. Except for Yili Kazak Autonomous Prefecture, the suitable areas for AT_JA were widely 3. Results distributed in Xinjiang. The suitable areas for FFP were mainly distributed in Aksu Pre- 3.1. Suitable Climate Area for Cotton Seed Production fecture, Hotan Prefecture, Kashgar Prefecture, Bayingol Mongolian Autonomous Prefec- ture, Amongand Tulufan. the inﬂuencing The suitable factors areas of for climate DD_35 suitability were mainly for early-maturing distributed in northern cotton (EMC) Xin- jiang,seed production,Hotan Prefecture, the suitable Aksu Prefecture, AAE_10 areas and were Kashgar distributed Prefecture in southern,in southern northern, Xinjiang. and In addition,eastern Xinjiang, the suitable and areas among of them,SR_AO the were suitable widely areas distributed were larger in eastern in southern Xinjiang. Xinjiang. The suitableExcept for area Yili for Kazak ASH Autonomous was distributed Prefecture, in all regions the suitable of Xinj areasiang, for except AT_JA Bortala were widely Mongol dis- Autonomoustributed in Xinjiang. Prefecture. The suitableThe suitable areas Pre_SO for FFP area were was mainly mainly distributed distributed in Aksu in eastern Prefecture, and southernHotan Prefecture, Xinjiang and Kashgar less so Prefecture, in northern Bayingol Xinjiang Mongolian (Figure 4). Autonomous Prefecture, and Tulufan.Among The the suitable factors areas affecting for DD_35 climate were suitability mainly distributed for early–medium-maturing in northern Xinjiang, cotton Hotan (EMMC)Prefecture, seed Aksu production, Prefecture, the and suitable Kashgar AAE_10 Prefecture areas in for southern EMMC Xinjiang. are also In distributed addition, the in suitable areas of SR_AO were widely distributed in eastern Xinjiang. The suitable area for ASH was distributed in all regions of Xinjiang, except Bortala Mongol Autonomous Prefecture. The suitable Pre_SO area was mainly distributed in eastern and southern Xinjiang and less so in northern Xinjiang (Figure4). Agriculture 2021, 11, x FOR PEER REVIEW 10 of 22

southern, northern, and eastern Xinjiang, and among them, the suitable areas are larger in southern Xinjiang. The suitable FFP areas for EMMC are mainly distributed in Aksu Prefecture, Kashgar Prefecture, and Hotan Prefecture of southern Xinjiang, eastern Bay- ingol Mongolian Autonomous Prefecture, and Turpan of eastern Xinjiang. The suitable AAE_15 areas are mainly distributed in southern Xinjiang, while there is minimal distribution in eastern and northern Xinjiang. The suitable DD_15 areas are mainly distributed in southern Xinjiang and the Turpan area of eastern Xinjiang, while the distribution in other areas is relatively small (Figure 5). Agriculture 2021, 11, x FOR PEER REVIEW 10 of 22 The suitable AAE_10 areas for long staple cotton (LSC) are mainly distributed in southern Xinjiang, less so in eastern Xinjiang than in southern Xinjiang, and sporadically in northern Xinjiang. The distribution of other climatic factors, such as AT_JA, DD_35, southern,SR_AO, ASH, northern, and Pre_SO and eastern for EMMC Xinjiang, and andLSC, among is the same them, as the that suitable for EMC areas (Figure are larger 6). in southernUnder theXinjiang. restriction The ofsuitable the suitable FFP areas area of for the EMMC above factors,are mainly the suitabledistributed climate in Aksu area Prefecture,for early-maturing Kashgar cotton Prefecture, (EMC) and seed Hotan production Prefecture is 2.94 of southern× 107 ha, andXinjiang, it is distributed eastern Bay- in ingolNorth Mongolian and South AutonomousXinjiang. The Prefecture,suitable climat ande Turpanarea of Aksuof eastern Prefecture, Xinjiang. Kashgar The suitable Prefec- AAE_15ture, and areas Hotan are Prefecture mainly distributed in the Tarim in Basin southe ofrn South Xinjiang, Xinjiang while is witheredely is distributed. minimal distri- The butionareas suitable in eastern for andearly–medium-maturing northern Xinjiang. The cotton suitable (EMMC) DD_15 and areas long are staplemainly cotton distributed (LSC) 7 7 Agriculture 2021, 11, 759 inseed southern production Xinjiang are 2.20and ×the 10 Turpan and 2.21 area × 10of easternha, respectively. Xinjiang, Bothwhile the the suitable distribution climate10 of 23in otherareas areasfor EMMC is relatively and LSC small are (Figure mainly 5). distribute d in the eastern part of the Tarim Basin (FiguresThe 4–6).suitable AAE_10 areas for long staple cotton (LSC) are mainly distributed in southern Xinjiang, less so in eastern Xinjiang than in southern Xinjiang, and sporadically in northern Xinjiang. The distribution of other climatic factors, such as AT_JA, DD_35, SR_AO, ASH, and Pre_SO for EMMC and LSC, is the same as that for EMC (Figure 6). Under the restriction of the suitable area of the above factors, the suitable climate area for early-maturing cotton (EMC) seed production is 2.94 × 107 ha, and it is distributed in North and South Xinjiang. The suitable climate area of Aksu Prefecture, Kashgar Prefec- ture, and Hotan Prefecture in the Tarim Basin of South Xinjiang is widely distributed. The areas suitable for early–medium-maturing cotton (EMMC) and long staple cotton (LSC) seed production are 2.20 × 107 and 2.21 × 107 ha, respectively. Both the suitable climate areas for EMMC and LSC are mainly distributed in the eastern part of the Tarim Basin (Figures 4–6).

Figure 4.4. SuitableSuitable climateclimate areaarea forfor early-maturingearly-maturing cottoncotton seedseed production,production, AAE_10,AAE_10, thethe activeactive accumulatedaccumulated temperaturetemperature equalequal toto oror greatergreater thanthan 1010 ◦°C;C; AT_JA, the average temperature in July and August;August; FFP, thethe frost-freefrost-free period;period; DD_35,DD_35, thethe ℃ duration in daysdays ofof temperaturetemperature equalequal toto oror greatergreater thanthan 3535◦C;; SR_AO, the sunshine rate fr fromom April to October; ASH, annual sunshine hours; Pre_SO, precipitation from September to October. annual sunshine hours; Pre_SO, precipitation from September to October.

Among the factors affecting climate suitability for early–medium-maturing cotton (EMMC) seed production, the suitable AAE_10 areas for EMMC are also distributed in southern, northern, and eastern Xinjiang, and among them, the suitable areas are larger in southern Xinjiang. The suitable FFP areas for EMMC are mainly distributed in Aksu Prefecture, Kashgar Prefecture, and Hotan Prefecture of southern Xinjiang, eastern Bayingol Mongolian Autonomous Prefecture, and Turpan of eastern Xinjiang. The suitable AAE_15 Figure 4. Suitable climate areaareas for areearly-maturing mainly distributed cotton seed in southernproduction, Xinjiang, AAE_10, whilethe active there accumulated is minimal temperature distribution in equal to or greater than 10 °C;eastern AT_JA, and the northern average temperature Xinjiang. The in suitableJuly and DD_15August; areasFFP, the are frost-free mainly distributed period; DD_35, in southern the duration in days of temperatureXinjiang equal and to theor greater Turpan than area 35 of℃;eastern SR_AO,Xinjiang, the sunshine while rate the from distribution April to October; in other ASH, areas is annual sunshine hours; Pre_SO,relatively precip smallitation (Figure from September5). to October.

Figure 5. Suitable climate area for early–medium-maturing cotton seed production, AAE_10, the active accumulated temperature equal to or greater than 10 ◦C; AT_JA, the average temperature in July and August; FFP, the frost-free period; DD_35, the duration in days of temperature equal to or greater than 35 ◦C; AAE_15, the active accumulated temperature greater than 15 ◦C; SR_AO, the sunshine rate from April to October; ASH, annual sunshine hours; Pre_SO, precipitation from September to October; DD_15, the duration in days of temperature equal to or greater than 15 ◦C.

The suitable AAE_10 areas for long staple cotton (LSC) are mainly distributed in southern Xinjiang, less so in eastern Xinjiang than in southern Xinjiang, and sporadically in northern Xinjiang. The distribution of other climatic factors, such as AT_JA, DD_35, SR_AO, ASH, and Pre_SO for EMMC and LSC, is the same as that for EMC (Figure6). Agriculture 2021, 11, x FOR PEER REVIEW 11 of 22

Figure 5. Suitable climate area for early–medium-maturing cotton seed production, AAE_10, the active accumulated temperature equal to or greater than 10 °C; AT_JA, the average temperature in July and August; FFP, the frost-free period; AgricultureDD_35,2021 the, 11 ,duration 759 in days of temperature equal to or greater than 35℃; AAE_15, the active accumulated temperature11 of 23 greater than 15 °C; SR_AO, the sunshine rate from April to October; ASH, annual sunshine hours; Pre_SO, precipitation from September to October; DD_15, the duration in days of temperature equal to or greater than 15 °C.

Figure 6.6. Suitable climate area for long staple cotton seed production,production, AAE_10, the active accumulatedaccumulated temperature equal toto oror greatergreater thanthan 1010 ◦°C;C; AT_JA, the average temperature in July and August; DD_35, the durationduration in days of temperature ℃ equalequal toto oror greatergreater thanthan 3535◦C;; SR_AO, SR_AO, the the sunshine sunshine rate rate from April to October;October; ASH, annual sunshine hours; Pre_SO, precipitation from September to October. precipitation from September to October.

3.2. SuitableUnder theSoil restrictionand Water ofArea the for suitable Cotton area Seed of Production the above factors, the suitable climate area for early-maturingConsidering the cotton limitation (EMC) of seed topography production on iscotton 2.94 × seed107 ha,production, and it is distributedthe area with in Northslopes andof less South than Xinjiang. 5 degrees The was suitable selected climate as the area suitable of Aksu slope Prefecture, area for Kashgar cotton Prefecture, seed pro- andduction Hotan in this Prefecture study. inIt thecan Tarimbe seen Basin from of th Southe figure Xinjiang that except is widely for distributed.the Altai Mountains, The areas suitableTianshan for Mountains, early–medium-maturing Kunlun Mountains, cotton and (EMMC) other high and mountain long staple areas, cotton the (LSC)other areas seed productionwere suitable are slope 2.20 × areas107 andfor cotton 2.21 × seed107 ha, production. respectively. The Both suitable the suitable planting climate soil for areas cotton for EMMCis sandy and loam; LSC therefore, are mainly the distributed suitable ST in theareas eastern for cotton part of seed the Tarimproduction Basin (Figureswere mainly4–6). distributed in northern Xinjiang. The soil depth and soil PH for the cotton seed production 3.2.area Suitableneed to Soilbe greater and Water than Area 30 cm for Cottonand greater Seed Productionthan 6.5 and less than 8, respectively. It can be seenConsidering from the figure the limitation that only ofa small topography part of onthe cotton study seedarea was production, unsuitable the for area SD with and slopesS_PH. Except of less thanfor the 5 degreessouthwest was of selected the Altay as theregion, suitable the south slope of area the for Turpan cotton and seed Hami pro- ductionregion, and in this the study.middle It of can the beTurpan seen fromBasin, the the ﬁgure suitable that areas except of river for the density Altai were Mountains, widely Tianshandistributed. Mountains, The suitable Kunlun TAW Mountains, areas were andspread other over high the mountain whole region. areas, the other areas wereThe suitable suitable slope soil areas and forwater cotton areas seed for production. EMC, EMMC, The and suitable LSC were planting obtained soil for by cotton bind- ising sandy ST, SD, loam; S_PH, therefore, DD, and the TAW suitable together. ST areas The for suitable cotton soil seed and production water areas were for mainly EMC, distributedEMMC, and in LSC northern were the Xinjiang. same, with The 1.46 soil depth× 107 ha, and and soil were PH widely for the distributed cotton seed in produc- north- tionern Xinjiang area need (Figure to be greater7). than 30 cm and greater than 6.5 and less than 8, respectively. It can be seen from the ﬁgure that only a small part of the study area was unsuitable for SD and S_PH. Except for the southwest of the Altay region, the south of the Turpan and Hami region, and the middle of the Turpan Basin, the suitable areas of river density were widely distributed. The suitable TAW areas were spread over the whole region. The suitable soil and water areas for EMC, EMMC, and LSC were obtained by binding ST, SD, S_PH, DD, and TAW together. The suitable soil and water areas for EMC, EMMC, and LSC were the same, with 1.46 × 107 ha, and were widely distributed in northern Xinjiang (Figure7).

Agriculture 11 Agriculture2021 2021, ,, 75911, x FOR PEER REVIEW 12 of12 22 of 23

Agriculture 2021, 11, x FOR PEER REVIEW 12 of 22

FigureFigure 7. Suitable7. Suitable water water and and soil soil area area for for cotton cotton seedseed production,production, ST, ST, soil texture; texture; SD, SD, soil soil depth; depth; S_PH, S_PH, soil soil PH; PH; DD, DD, drainage density; TAW, the average annual total amount of water resources per unit area. drainageFigure density;7. Suitable TAW, water the and average soil area annual for totalcotton amount seed production, of water resources ST, soil pertexture; unit SD, area. soil depth; S_PH, soil PH; DD, drainage density; TAW, the 3.3.average Low-Risk annual Production total amount Area of waterfor Cotton resources Seed Productionper unit area. 3.3. Low-Risk Production Area for Cotton Seed Production 3.3. Low-RiskExcept forProduction the southwest Area for ofCotton Bayingol Seed ProductionMongolian Autonomous Prefecture and the southeastExcept of for Tarbagatay the southwest Prefecture, of Bayingol the whole Mongolian region was Autonomous an FMD low-risk Prefecture area. Except and the Except for the southwest of Bayingol Mongolian Autonomous Prefecture and the for the southwest of Bayingolin Autonomous Prefecture, eastern Hotan Prefecture, and a southeastsoutheast of Tarbagatay Tarbagatay Prefecture, Prefecture, the thewhole whole region region was an was FMD an low-risk FMD area. low-risk Except area. small part of Kashgar Prefecture, the whole region was an FPD low-risk area. The PCR Exceptfor the forsouthwest the southwest of Bayingolin of Bayingolin Autonomous Autonomous Prefecture, Prefecture,eastern Hotan eastern Prefecture, Hotan and Prefec- a low-risk area was mainly distributed in northern and southern Xinjiang and less so in ture,small and part a smallof Kashgar part ofPrefecture, Kashgar Prefecture,the whole region the whole was an region FPD waslow-risk an FPD area. low-risk The PCR area. eastern Xinjiang. Excluding the northern Altay Prefecture, northern Tarbagatay Prefec- Thelow-risk PCR low-riskarea was areamainly was dist mainlyributed distributed in northern in and northern southern and Xinjiang southern and Xinjiang less so in and ture, Ili Kazakh Autonomous Prefecture, Changji Hui Autonomous Prefecture, and north- lesseastern so in Xinjiang. eastern Xinjiang.Excluding Excluding the northern the Alta northerny Prefecture, Altay Prefecture, northern Tarbagatay northern Tarbagatay Prefec- ern Hami, the remainder were AYR low-risk areas. Prefecture,ture, Ili Kazakh Ili Kazakh Autonomous Autonomous Prefecture, Prefecture, Changji Changji Hui Autono Huimous Autonomous Prefecture, Prefecture, and north- and To sum up, the low-risk production areas for EMC, EMMC, and LSC were also the northernern Hami, Hami, the remainder the remainder were AYR were low-risk AYR low-risk areas. areas. same. The low-risk area for cotton seed production was 6.08 × 107 ha, which was mainly ToTo sum sum up,up, thethe low-risklow-risk production area areass for for EMC, EMC, EMMC, EMMC, and and LSC LSC were were also also the the distributed in the western region of the Junggar basin in the north and7 the western region same.same. The The low-risklow-risk areaarea forfor cotton seed production production was was 6.08 6.08 × ×10107 ha,ha, which which was was mainly mainly of the Tarim Basin in the south (Figure 8). distributeddistributed inin thethe westernwestern region of of the the Junggar Junggar basin basin in in the the north north and and the the western western region region ofof the the Tarim Tarim Basin Basin inin thethe southsouth (Figure 88).).

Agriculture 2021, 11, x FOR PEER REVIEW 13 of 22

Figure 8. Suitable production risk area for cotton seed production, FMD, the frequency of meteorological disasters; FPD, the frequency of pest diseases; PCR, the precipitation change rate; AYR, the average cotton yield reduction rate over the years. Agriculture 2021, 11, 759 13 of 23 3.4. Suitable Social–Economic Area for Cotton Seed Production The suitable social–economic area for EMC, EMMC, and LSC were also the same. Areas3.4. Suitable with high Social–Economic ACY were spread Area for over Cotton the Seed study Production region, except for the Altay Prefecture, southernThe suitableIli Kazak social–economic Autonomous Prefecture area for,EMC, Urumqi, EMMC, and eastern and LSC Changji werealso Huithe Autono- same. mousAreas Prefecture. with high ACYExcept were for spreadthe middle over part the studyof the region,Tarim Basin, except the for road the Altaynetwork Prefecture, density insouthern other areas Ili Kazak was Autonomousrelatively high. Prefecture, In terms Urumqi,of AFE, the and suitable eastern areas Changji for Hui cotton Autonomous seed pro- ductionPrefecture. were Except mainly for located the middle in the part northern of the Tarim and Basin,southwestern the road Xinjiang. network densityWith regard in other to DCE,areas the was areas relatively suitable high. for Incotton terms seed of AFE, production the suitable were areasmainly for distributed cotton seed in productionthe central andwere western mainly parts located of Xinjiang, in the northern with a circular and southwestern distributionXinjiang. around seed With production regard to enter- DCE, prises.the areas suitable for cotton seed production were mainly distributed in the central and westernUnder parts the of restriction Xinjiang, of with the a above circular social distribution and economic around factors, seed production the suitable enterprises. social and economicUnder zone the for restriction cotton seed of the production above social was and 1.23 economic × 107 ha and factors, was the mainly suitable located social inand the northeconomic of Bayingol zone for Mongolian cotton seed Autonomous production Prefecture, was 1.23 × the107 middleha and and was north mainly of Aksu located Pre- in fecture,the north the of middle Bayingol of Kashgar Mongolian Prefecture, Autonomous the west Prefecture, of Turpan, the the middle middle and of north Changji of Aksu Hui AutonomousPrefecture, the Prefecture middle of Kashgarand Karamay, Prefecture, the we thest west of Bortala of Turpan, Mongol the middle Autonomous of Changji Prefec- Hui tureAutonomous and Ili Kazak Prefecture Autonomous and Karamay, Prefecture, the west and ofthe Bortala north of Mongol Tarbagatay Autonomous Prefecture Prefecture (Figure 9).and Ili Kazak Autonomous Prefecture, and the north of Tarbagatay Prefecture (Figure9).

Figure 9. Suitable social and economic area fo forr cotton seed production, ACY, ACY, the a annualnnual cotton yield; RD, road density; AFE, the accessibility of farmland to seed production enterprises;enterprises; DCE, the densitydensity ofof cottoncotton seedseed productionproduction enterprises.enterprises.

3.5. Cotton Production History 3.5. Cotton Production History There has been cotton seed production in the north of the Kashgar Prefecture, Aksu Prefecture,There hasTarbagatay been cotton Prefecture, seed production and Bort inala the Mongol north ofAutonomous the Kashgar Prefecture; Prefecture, Aksuthus, thesePrefecture, areas are Tarbagatay suitable for Prefecture, seed production and Bortala from Mongol the perspective Autonomous of historical Prefecture; suitability thus, (Figurethese areas 10). are suitable for seed production from the perspective of historical suitability (Figure 10).

Agriculture 2021, 11, x FOR PEER REVIEW 14 of 22 Agriculture 2021, 11, 759 14 of 23

Figure 10. Suitable area for cotton seed production with regard to production history. Figure 10. Suitable area for cotton seed production with regard to production history. 3.6. Comprehensive Suitable Area for Cotton Seed Production 3.6.1. Early-Maturing Cotton (EMC) Seed Production Suitability 3.6. Comprehensive Suitable Area for Cotton Seed Production Based on the hierarchical classification, we integrated the climate suitability, soil and 3.6.1.water Early-Maturing suitability, social–economic Cotton (EMC) suitability, Seed production Production risk, andSuitability planting history to de- velopBased the spatial on the distribution hierarchical of EMC classification, seed production we suitability. integrated The the appropriate climate area suitability, for soil and seed production of EMC was 6.4 × 105 ha, and it was mainly distributed in the Kashgar waterPrefecture, suitability, Hotan Prefecture, social–economic and Aksu suitability, Prefecture of production southern Xinjiang. risk, andAmong planting the ap- history to de- veloppropriate the areas,spatial the distribution superior area wasof EMC 2.3 × 10seed5 ha, pr whichoduction was mainly suitability. distributed The in appropriate the area formiddle seed of production the Aksu Prefecture of EMC and was the 6.4 north × 10 of5 theha, Kashgar and it was Prefecture. mainly Aksu distributed City, Payza- in the Kashgar Prefecture,wat County, Hotan Makit County, Prefecture, Shule County,and Aksu and WensuPrefecture County of were southern the top Xinjiang. five superior Among the ap- areas for EMC seed production. The suitable area was 9.7 × 104 ha, which was mainly propriate areas, the superior area was 2.3 × 105 ha, which was mainly distributed in the distributed in the northwest of Kashgar Prefecture. Atushi City, Yopurga County, Qeshqer middleShehiri, of Aketao the Aksu County, Prefecture and Shufu Countyand the were north the topof the five Kashgar suitable areas Prefecture. for EMC seedAksu City, Payz- awatproduction. County, The Makit sub-suitable County, area Shule was County, 3.1 × 105 andha, which Wensu was County mainly were distributed the top in five superior areasthe north for ofEMC the Kashgarseed production. Prefecture and The the suitable middle of area the Aksu was Prefecture. 9.7 × 104 Akesuha, which City, was mainly distributedMarabishi County, in the Kuqa northwest County, Shaya of Kashgar County, and Prefecture. Yengisar County Atushi were City, the top Yopurga five County, sub-suitable areas for EMC seed production (Figures 11a and 12). Qeshqer Shehiri, Aketao County, and Shufu County were the top five suitable areas for EMC seed production. The sub-suitable area was 3.1 × 105 ha, which was mainly distributed in the north of the Kashgar Prefecture and the middle of the Aksu Prefecture. Akesu City, Marabishi County, Kuqa County, Shaya County, and Yengisar County were the top five sub-suitable areas for EMC seed production (Figures 11a and 12).

3.6.2. Early–Medium-Maturing Cotton (EMMC) Seed Production Suitability The appropriate area for seed production of EMMC was 5.5 × 105 ha, and it was mainly distributed in the north of the Kashgar Prefecture, the middle of the Aksu Prefec- ture, and the Hotan Prefecture. Among the appropriate areas, the superior area was 2.2 × 105 ha, which was distributed in the north of the Kashgar Prefecture and the middle of the Aksu Prefecture. Aksu City, Payzawat County, Makit County, Shule County, and Wensu County were the top five superior areas for EMMC seed production. The suitable area was 6.8 × 104 ha, which was distributed in the northwest of the Kashgar Prefecture. Payz- awat County, Yopurga County, Qeshqer Shehiri, Aketao County, and Shufu County were the top five suitable areas for EMMC seed production. The sub-suitable area was 2.7 × 105 ha and was distributed in the north of the Kashgar Prefecture, the middle and west of the Hotan Prefecture, and the middle of the Aksu Prefecture. Akesu City, Marabishi County, Kuqa County, Shaya County, and Yengisar County were the top five sub-suitable areas for EMMC seed production (Figures 11b and 12).

Agriculture 2021, 11, 759 15 of 23 Agriculture 2021, 11, x FOR PEER REVIEW 16 of 23

FigureAgricultureFigure 11. 2021Spatial 11., 11 Spatial, x distributionFOR distributionPEER REVIEW of cottonof cotton seed seed production production suitability:suitability: (a (a) )early early-maturing-maturing cotton; cotton; (b) early (b) early–medium-maturing–medium-maturing17 of 22

cotton;cotton; (c) long (c) staplelong staple cotton; cotton; (d) ( comprehensived) comprehensive suitability suitability ofof cottoncotton seed seed pr production.oduction.

Table 2. Suitable for the three varieties of cotton seed production area (unit: ha).

1a1b1c 2a2b2c 3a3b3c 1a1b1c 2a2b2c 3a3b3c Aksu City 13,120.09 -- 297.35 Makit County 25,019.14 -- 1334.95 Aketao County 4.27 128.89 -- Karakax County -- -- 992.68 Atush City -- 4883.96 874.41 Pishan County -- -- 10,441.60 Marabishi County 38.83 -- 26,639.46 Shaya County 2875.25 -- 57,310.81 Qira County -- -- 5838.12 Yarkant County 12,177.45 -- -- Payzawat County 13,474.88 141.73 7172.27 Shufu County 64.58 25,571.23 -- Hotan County -- -- 3122.02 Shule County 32,576.64 59.99 3629.58 Kalpin County -- -- 1521.36 Yuli County -- -- 136.45 Kuqa City -- -- 25,008.14 Xinhe County -- -- 8990.72 Bugur County -- -- 7893.04 Yengisar County 2697.67 -- 24,448.64 Lop County -- -- 1198.96 Yutian County -- -- 8637.22 Qeshqer Shehiri 56.96 12,172.54 -- Yopurga County -- 8716.17 --

FigureFigure 12. 12.Suitable Suitable area area of of cottoncotton seed producti productionon in indifferent different counties. counties. (unit: (unit: ha). ha).

4. Discussion 4.1. Comparison of the Results According to the average planting area of cotton in Xinjiang from 2008 to 2018, the whole region of Xinjiang can be divided into north Xinjiang cotton-free area, north Xin- jiang cotton area, east Xinjiang cotton area, north Tarim Basin cotton area, west Tarim Basin cotton area, and east Tarim Basin cotton area (Figure 13a). The planting areas of long staple cotton (LSC) are mainly in the northwest edge of south Tarim Basin and Wusu city in Northern Xinjiang (Figure 13b). In this study, the candidate areas of LSC seed production included the superior and sub-suitable areas in Aksu Prefecture, which are located in the southern piedmont of Tianshan Mountain, the superior, suitable, and sub-suitable areas in the Kashgar Prefecture of the western margin of Tarim Basin, and the sub-suitable areas in the Hotan Prefecture in the southern margin of Tarim Basin. Compared with the existing planting areas of LSC, the layout of LSC in this study does not exist in north Xinjiang, which is mainly because the active accumulated temperature greater than or equal to 10 °C in north Xinjiang does not meet the re- quirement of 4000 °C. Early-maturing cotton (EMC) planting areas are distributed in both south and north Xinjiang, and the EMC planting area in North Xinjiang is the largest [37]. The EMC planting area in north Xinjiang is located in the north slope of the Tianshan Mountains, southwest edge of Junggar basin, and south of the Gurbantonggut desert, while the EMC planting area in south Xinjiang is mainly distributed in the west of Tarim Basin [37] (Figure 13c). In this study, the alternative areas for EMC seed production were mainly distributed in the Aksu Prefecture in the southern piedmont of the Tianshan Mountain (Superior and suitable area), the Kashgar Prefecture (Superior and suitable area) and the Kizilsu Kirghiz Autonomous Prefecture (Suitable area) of the western margin of Tarim Basin, the Bayingol Mongolian Autonomous Prefecture (Sub-suitable area) in the eastern section of the southern foot of the Tianshan Mountain, and the sub-suitable areas in the Hotan Prefecture in the southern margin of Tarim Basin. The appropriate area of EMC seed production was

Agriculture 2021, 11, 759 16 of 23

3.6.2. Early–Medium-Maturing Cotton (EMMC) Seed Production Suitability The appropriate area for seed production of EMMC was 5.5 × 105 ha, and it was mainly distributed in the north of the Kashgar Prefecture, the middle of the Aksu Pre- fecture, and the Hotan Prefecture. Among the appropriate areas, the superior area was 2.2 × 105 ha, which was distributed in the north of the Kashgar Prefecture and the middle of the Aksu Prefecture. Aksu City, Payzawat County, Makit County, Shule County, and Wensu County were the top five superior areas for EMMC seed production. The suitable area was 6.8 × 104 ha, which was distributed in the northwest of the Kashgar Prefecture. Payzawat County, Yopurga County, Qeshqer Shehiri, Aketao County, and Shufu County were the top five suitable areas for EMMC seed production. The sub-suitable area was 2.7 × 105 ha and was distributed in the north of the Kashgar Prefecture, the middle and west of the Hotan Prefecture, and the middle of the Aksu Prefecture. Akesu City, Marabishi County, Kuqa County, Shaya County, and Yengisar County were the top five sub-suitable areas for EMMC seed production (Figures 11b and 12).

3.6.3. Long Staple Cotton (LSC) Seed Production Suitability The appropriate area for seed production of LSC was 3.6 × 105 ha and was distributed in the north of the Kashgar Prefecture, the middle and west of the Hotan Prefecture, and the east of the Aksu Prefecture. Among the appropriate areas, the superior was 1.1 × 105 ha, which is distributed in the northern part of the Kashgar Prefecture and the central and southern part of the Aksu Prefecture. Aksu City, Payzawat County, Makit County, Shule County, and Yarkant County were the top five superior areas for LSC seed production. The suitable area was 5.3 × 104 ha, which was distributed in the northwest of the Kashgar Prefecture. Atush City, Payzawat County, Yopurga County, Qeshqer Shehiri, and Shufu County were the top five suitable areas for LSC seed production. The sub-suitable area was 2.1 × 105 ha, which was distributed in the north of the Kashgar prefecture, the east of the Aksu Prefecture, and the mid-west area of the Hotan Prefecture. Marabishi County, Kuqa County, Pishan County, Shaya County, and Yengisar County were the top five sub-suitable area for LSC seed production (Figures 11c and 12).

3.7. Comprehensive Suitability for the Three Varieties of Cotton Seed Production Aeras We integrated the suitability of seed production for three kinds of cotton to obtain the integrated layout of cotton seed production. There are only three types of combinations among the suitability of seed production for EMC, EMMC, and LSC, which are 1a1b1c, with 1.0 × 105 ha (superior for EMC, EMMC, or LSC seed production); 2a2b2c, with 5.2 × 104 ha (suitable for EMC, EMMC, or LSC seed production); and 3a3b3c, with 2.0 × 105 ha (sub-suitable for EMC, EMMC, or LSC seed production). The major superior areas for producing cotton seed of EMC, EMMC, and LSC seed production included Shule County, Makit County, Payzawat County, Aksu City, and Yarkant County. The suitable areas for EMC, EMMC, and LSC seed production included Shufu County, Qeshqer Shehiri, and Yopurga County, accounting for nearly 90% of the total suitable areas for EMC, EMMC, and LSC seed production. The sub-suitable areas for EMC, EMMC, and LSC seed production were relatively large, with Shaya County, Marabishi County, Kuqa City, and Yengisar County being the most distributed (Figure 11d, Table2). Agriculture 2021, 11, 759 17 of 23

Table 2. Suitable for the three varieties of cotton seed production area (unit: ha).

1a1b1c 2a2b2c 3a3b3c 1a1b1c 2a2b2c 3a3b3c Makit Aksu City 13,120.09 – 297.35 25,019.14 – 1334.95 County Karakax Aketao County 4.27 128.89 – – – 992.68 County Pishan Atush City – 4883.96 874.41 – – 10,441.60 County Shaya Marabishi County 38.83 – 26,639.46 2875.25 – 57,310.81 County Yarkant Qira County – – 5838.12 12,177.45 – – County Shufu Payzawat County 13,474.88 141.73 7172.27 64.58 25,571.23 – County Shule Hotan County – – 3122.02 32,576.64 59.99 3629.58 County Yuli Kalpin County – – 1521.36 – – 136.45 County Xinhe Kuqa City – – 25,008.14 – – 8990.72 County Yengisar Bugur County – – 7893.04 2697.67 – 24,448.64 County Yutian Lop County – – 1198.96 – – 8637.22 County Yopurga Qeshqer Shehiri 56.96 12,172.54 – – 8716.17 – County

seed production was consistent with the existing EMC planting area. However, different from the existing planting areas of EMC, the superior areas, suitable areas, and sub- suitable areas obtained from the research results were also distributed in other areas; these areas are potential areas for future cotton seed production, which should be given high priorities in future EMC seed production. The appropriate areas for early–medium-maturing cotton (EMMC) seed production in the northwest and southwest of Tarim Basinare were consistent with EMMC planting areas [37] (Figure 13d). However, in the eastern part of Tarim Basin and Hami of eastern Agriculture 2021, 11, 759 Xinjiang, even if there is EMMC cotton planting, it is not suitable for EMMC18 seed of 23 production, mainly because the climate conditions in these two areas are not suitable, and in addition, the social and economic suitability is not good.

FigureFigure 13.13. (a) AverageAverage cottoncotton planting planting area area in in Xinjiang Xinjiang from from 2008–2018; 2008–2018; (b ()b Average) Average long long staple staple cotton cotton (LSC) (LSC) planting planting area area in Xinjiangin Xinjiang from from 2008–2018 2008–2018 and and appropriate appropriate areas areas for LSCfor LSC seed seed production; production; (c) existing (c) existing early–maturing early–maturing cotton cotton (EMC) (EMC) areas areas and appropriateand appropriate areas forareas EMC for seed EMC production;( seed productiod) Existingn;(d) early–medium–maturingExisting early–medium– cottonmaturing (EMMC) cotton areas (EMMC) and appropriate areas and areasappropriate for EMMC areas seed for EMMC production. seed (Note:production. the data (Note: of the the average data of cottonthe average planting cotton area planting came from area the came Statistical from the yearbook Statistical of theyearbook Xinjiang of Uygurthe Xinjiang Autonomous Uygur Autonomous Region). Region).

4.2. SustainableEarly-maturing Devel cottonopment (EMC) of Cotton planting Seed areas Production are distributed in Xinjiang in both south and north Xinjiang,4.2.1. The and Necessity the EMC of plantingScientific area Layout in North of Cotton Xinjiang Seed is theProduction largest [37 ]. The EMC planting area inAgriculture north Xinjiang constitutes is located an important in the north part slope of the of economic the Tianshan development Mountains, of southwestthe desert edge of Junggar basin, and south of the Gurbantonggut desert, while the EMC planting area oasis in Xinjiang, while the ecological environment of the desert oasis is relatively fragile, in south Xinjiang is mainly distributed in the west of Tarim Basin [37] (Figure 13c). In this and water resources are scarce [38]. How to use the limited agricultural production study, the alternative areas for EMC seed production were mainly distributed in the Aksu Prefecture in the southern piedmont of the Tianshan Mountain (Superior and suitable area), the Kashgar Prefecture (Superior and suitable area) and the Kizilsu Kirghiz Autonomous Prefecture (Suitable area) of the western margin of Tarim Basin, the Bayingol Mongolian

Autonomous Prefecture (Sub-suitable area) in the eastern section of the southern foot of the Tianshan Mountain, and the sub-suitable areas in the Hotan Prefecture in the southern margin of Tarim Basin. The appropriate area of EMC seed production was consistent with the existing EMC planting area. However, different from the existing planting areas of EMC, the superior areas, suitable areas, and sub-suitable areas obtained from the research results were also distributed in other areas; these areas are potential areas for future cotton seed production, which should be given high priorities in future EMC seed production. Agriculture 2021, 11, 759 19 of 23

The appropriate areas for early–medium-maturing cotton (EMMC) seed production in the northwest and southwest of Tarim Basinare were consistent with EMMC planting areas [37] (Figure 13d). However, in the eastern part of Tarim Basin and Hami of eastern Xinjiang, even if there is EMMC cotton planting, it is not suitable for EMMC seed production, mainly because the climate conditions in these two areas are not suitable, and in addition, the social and economic suitability is not good.

4.2. Sustainable Development of Cotton Seed Production in Xinjiang 4.2.1. The Necessity of Scientific Layout of Cotton Seed Production Agriculture constitutes an important part of the economic development of the desert oasis in Xinjiang, while the ecological environment of the desert oasis is relatively fragile, and water resources are scarce [38]. How to use the limited agricultural production resources to obtain the maximum output is a problem to which the local government, enterprises, and farmers pay close attention. Crop seed industry can optimize agricultural planting structure, improve agricultural production efficiency, promote farmers’ employ- ment, and increase farmers’ income. Xinjiang has a large cotton planting area and a large demand for seeds. The annual seed production of the state-owned seed companies in Xinjiang is 150,000 tons, accounting for about 40% of the total seed consumption in the region, and the total sales of cotton seeds are 20 billion to 30 billion yuan [7]; cotton is still the crop with the greatest potential in the seed market. Compared with cotton production, the conditions for cotton seed production are much more stringent. However, Xinjiang government departments and cotton seed production enterprises are not sure how to scientifically arrange cotton seed production; cotton seed industry optimization layout in Xinjiang is imminent.

4.2.2. Rational Utilization of Agricultural Resources in Xinjiang Research on the distribution of the cotton seed industry is conducive to more scientific and rational agricultural resources in Xinjiang. The breeding of improved varieties is the key to cotton seed production. Compared with the seed production of other crops, cotton has a wide range of good breeding, a large quantity, and many connections. Therefore, arranging cotton seed bases according to the comprehensive power of each cotton area is an effective way of improving the development of cotton seeds in Xinjiang [39]. Climate is the key factor affecting cotton seed production. Relevant research has shown that in recent years, with the rapid development of cotton planting in southern Xinjiang, the excessive expansion of the planting scale due to the lack of attention given to the suitability of climate conditions or the unreasonable selection of variety maturity has led to a low and unstable cotton yield, a low percentage of flowers before frost, and a declining quality, which has seriously affected the economic benefits of cotton production [20]. Xinjiang has abundant land resources and stable water resources. There are vast piedmont alluvial plains in the Tarim and Junggar Basins and alluvial plains of different sizes along the Tarim River, Yarkant River, Manas River, Kuitun River, and Boertala River, which are rich in land resources. Precipitation in the Xinjiang plain is scarce, but there is a lot of water in the mountainous areas around the basin, with surface water resources of 79.3 billion cubic meters. The runoff is adjusted by alpine ice and snow melt water, and the annual change is gentle, which provides a stable and reliable water source for irrigation and cotton planting [28]. However, with the increase in the cotton production scale, the environmental pressure of cotton production in Xinjiang will increase. The water demand characteristics of cotton are consistent with the water regime and climate characteristics of Xinjiang. Before the scale expansion, the environment supported the development of cotton production. However, with the expansion of the scale, cotton has become a major water user in Xinjiang, and it will be difficult for the limited water resources to support the continuous increase in the cotton planting scale. In addition, the problems of soil fertility decline, salinization, and residual film pollution in cotton fields are increasing [6]. Agriculture 2021, 11, 759 20 of 23

Therefore, in order to realize the development of the cotton seed industry, the sustainable utilization of water and soil resources must be taken into account. Diseases and pests in the Xinjiang cotton area mainly include cotton bollworm disease and cotton aphid wilt. Therefore, in cotton seed production, priority should be given to disease-resistant varieties and biological control, and comprehensive management should be carried out [36]. During the whole growth cycle, from sowing to harvest, cotton may be damaged by disastrous weather, mainly including drought, high temperatures, strong wind, rain, hail, and freezing, which seriously affect the normal production of cotton, resulting in the reduction of yield and income or even no harvest in serious cases. Therefore, prevention work should be conducted in the prenatal period, the climate resources should be rationally used, the advantages and disadvantages should be avoided, and the yield and quality of cotton should be improved as much as possible. Selecting drought- and high-temperature- resistant cotton varieties and actively promoting advanced drip irrigation and other water- saving irrigation technologies can not only save water, but also promote the growth of cotton [29]. Cotton seed production enterprises guarantee the development of the cotton seed industry. There are more than 800 enterprises involved in cotton seed production and sales in Xinjiang. However, large enterprises account for less than 5%, and large and medium-sized enterprises account for less than 25% [39]. There is still considerable room for improvement in the development of cotton seed production enterprises in Xinjiang so as to realize the strong development of the cotton seed industry. In addition, FAO has introduced sustainable and innovative technologies and practices, namely, “climate-smart agriculture (CSA)”, which refers to any innovative practice and technology that helps to enhance farm productivity and farm income, as well as improving water and nutrient use efﬁciency and resilience to climatic stresses on a sustainable basis and lowering the emissions of greenhouse gas (GHG) to a minimum level [40]. Hence, cotton seed producers can use inputs in an efﬁcient way by using CSA practices and technologies in cotton growing areas. According to the layout plan in this study, the development of the cotton seed industry is conducive to the protection of resources and environmen, and the sustainable development of the cotton seed industry in Xinjiang.

5. Conclusions Based on multi-source data, we developed a hierarchical classiﬁcation method to identify the suitability of cotton seed production bases in this study. Following the research outlined in this paper, the conclusions are as follows: (1) The suitable climate areas for early-maturing cotton (EMC), early–medium-maturing cotton (EMMC), and long staple cotton (LSC) seed production are 2.94 × 107 ha, 2.20 × 107, and 2.21 × 107 ha, respectively. The largest distribution area of EMC was observed in the Aksu Prefecture, Kashgar Prefecture, and Hotan Prefecture in the Tarim Basin of South Xinjiang. Both of the suitable climate areas for EMMC and LSC were mainly distributed in the eastern part of the Tarim Basin. The soil and water suitable areas for EMC, EMMC, and LSC were the same at 1.46 × 107 ha, and they were widely distributed in northern Xinjiang. The low-risk area for cotton seed production was 6.08 × 107 ha, which was mainly distributed in the western region of the Junggar Basin in the north and the western region of the Tarim Basin in the south. The suitable social and economic zone for cotton seed production was 1.23 × 107 ha, which was mainly located in the north of the Bayingol Mongolian Autonomous Prefecture, the middle and north of the Aksu Prefecture, the middle of the Kashgar Prefecture, the west of Turpan, the middle of the Changji Hui Au- tonomous Prefecture and Karamay, the west of the Bortala Mongol Autonomous Prefecture and the Ili Kazak Autonomous Prefecture, and the north of the Tarbagatay Prefecture. Agriculture 2021, 11, 759 21 of 23

(2) The appropriate area for seed production of EMC, EMMC, and LSC was 6.40 × 105 ha, 5.53 × 105 ha, and 3.65 × 105 ha, respectively, and they were distributed in different areas of the Kashgar Prefecture, Hotan Prefecture, and Aksu Prefecture. (3) There were only three combinations among the examined areas that were suitable for seed production for EMC, EMMC, and LSC: (i) superior for EMC, EMMC, or LSC seed production: 1.02 × 105 ha; (ii) suitable for EMC, EMMC, or LSC seed production: 5.17 × 104 ha; (iii) sub-suitable for EMC, EMMC, or LSC seed production: 1.95 × 105 ha. The superior area for the production of cotton seed of EMC, EMMC, or LSC was located in the western Tarim Basin. The sub-suitable area for cotton seed production of EMC, EMMC, or LSC was mostly distributed in the western and northern Tarim Basin. Due to the different climate, soil, water resources, and management measures in different countries and regions, the varieties of cotton seed production varied. However, in any case, the following conditions should be met during the cotton seed production base selection: ﬁrst, the abundant light and heat resources, which provide unique ecological conditions for cotton production; secondly, the higher degree of mechanization, which provides the most convenient conditions for cotton production; thirdly, perfect agricultural infrastructure, which provides favorable conditions for the sustainable development of cotton; moreover, abundant water resources, which provide the most fundamental guarantee for the development of cotton agriculture; ﬁnally, excellent quality of soil fertility conditions, which provide a guarantee for cotton yield. Therefore, considering the above elements, the model developed in this study could be replicated in other areas in the world. In addition, the model was to delimit the cotton seed production base according to the current situation. If climate or other elements affecting cotton seed production changed, the model was capable of judging the change of planting area to a certain extent as well. Besides, this model could also help the government and banks more accurately determine where they will invest to promote the production of cotton seeds.

Author Contributions: Y.N.: Conceptualization, Methodology, Visualization, Writing—original draft, Writing—review and editing. G.X.: Funding acquisition, Supervision, Conceptualization, Methodology, Writing—review and editing. Y.X.: Funding acquisition, Conceptualization, Writing— review and editing. K.Q.: Writing—review and editing. J.L. (Jingya Liu): Writing—review and editing. Y.W.: Writing—review and editing. S.G.: Writing—review and editing. M.H.: Writing— review and editing. J.L. (Jia Liu): Writing—review and editing. C.Z. (Caixia Zhang): Writing—review and editing. C.Z. (Changshun Zhang): Writing—review and editing. All authors have read and agreed to the published version of the manuscript. Funding: This research was funded by Key Projects of Chinese Academy of Sciences “National Nutrition and Food Security in the New Period” (Grant No. KJZD-EW-G20-04 and ZDBS-SSW-DQC- 002-05), the Strategic Priority Research Program of Chinese Academy of Sciences (XDA2002040203), the National Key Research and Development Plan (No. 2016YFC0503403 and 2016YFC0503706), and the Program of National Natural Science Foundation of China (Grant No. 41971272). Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Not applicable. Acknowledgments: The authors would like to thank anonymous reviewers and the editor for their support, insightful critiques, and constructive comments. Conﬂicts of Interest: The authors declare no conﬂict of interest.

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