sustainability

Article Assessment of Cultivated Land Productivity and Its Spatial Differentiation in Dongting Lake Region: A Case Study of Yuanjiang City, Hunan Province

Chong Zhao 1, Yong Zhou 1,*, Xigui Li 1,*, Pengnan Xiao 1 and Jinhui Jiang 2 1 The College of Urban & Environmental Sciences, Central China Normal University, Wuhan 430079, China; [email protected] (C.Z.); [email protected] (P.X.) 2 School of Life Sciences, Central China Normal University, Wuhan 430079, China; [email protected] * Correspondence: [email protected] (Y.Z.); [email protected] (X.L.); Tel.: +86-027-67868305 (Y.Z.); +86-13035126896 (X.L.)


Received: 22 August 2018; Accepted: 8 October 2018; Published: 10 October 2018


Abstract: Cultivated land is an important carrier of grain production, and scientific assessing of cultivated land productivity is of great significance to ensure food security. This paper assessed the overall productivity of cultivated land in Yuanjiang city from the perspectives of quantitative structure, spatial distribution and correlation with national land use. We applied statistical and GIS (geographic information system) spatial analysis methods to 16 secondary indicators of productivity. The results showed that the productivity index of cultivated land ranged from 1642.79 to 4140.09, concentrated in classes 2–6, among the most productive of 15 classes in total. The cultivated productivity indexes of most towns showed quantitative structural patterns of “inverted pyramid” and “dumbbell” types. Cultivated lands with high productivity showed a spatial distribution that decreased from the north to the south and increased from the center to the periphery. The spatial distribution of the higher-level classes in the cultivated land productivity index and the national cultivated land use index was similar. The correlation coefficient between the indexes for cultivated land productivity and the annual standard crop yield was 0.8817, implying that the index reflected local grain production capacity very well. In general, the research offered a reference and technical support for the sustainable use of cultivated land resources and enhanced regional cultivated land production capacity.

Keywords: cultivated land productivity; comprehensive assessment; spatial differentiation; regression analysis; Yuanjiang city

1. Introduction Cultivated land is one of the fundamental elements that governs the production capacity of food and is an essential and important resource and material base for humans [1–3]. Recently, with the rapid development of urbanization and the continuous growth of the population in China, the quantity and quality of cultivated land has decreased, which has threatened food security and has put pressure on the protection of cultivated land [3,4]. Ensuring food production and security is the primary task for state administrators and is a major strategic issue for national economic development, social stability and national self-reliance [5,6]. Studying regional grain production capacity and spatial change is of great practical significance for the implementation of the policy to protect farmland and for guaranteeing food security [7–9]. Research into the productive capacity of cultivated land in countries outside China has mainly focused on the potential of land production and the influence of factors such as light, temperature, soi conditions and water conditions on crop yield [10,11]. In particular, the application of crop growth models [12], remote sensing production estimation models [13], multivariate statistical models [14]

Sustainability 2018, 10, 3616; doi:10.3390/su10103616 www.mdpi.com/journal/sustainability Sustainability 2018, 10, 3616 2 of 15 and other methods for crop growth monitoring and yield estimation have been emphasized. In China, since the 1970s when Huang first proposed the concept and methods for measuring potential crop photosynthesis [15], many studies have been undertaken from different perspectives, including on land productivity, crop climate productivity, crop, light and temperature productivity and cultivated land productivity [16–18]. Since Lester R. Brown asked, “who will feed China?”, problems with food security have become the focus of political and research attention around the world. Most research in China has looked at the conceptual models and theoretical systems in cultivated land productivity [19–21], mainly at the macro or meso spatial scales [22–25]. Researchers have calculated cultivated land productivity and have analyzed the differences in time and space and the influencing factors [25] based on the results of grading agricultural land [26], evaluating cultivated land quality [27] and testing regional yields [28] through the potential decay method, improved agricultural ecological zoning and the agro-ecological zone model [24,29,30], or building a new cultivated land productivity evaluation system [31]. However, most of these calculations of cultivated land productivity that are based on grading agricultural land are deficient in their evaluation because of a lack of indexes reflecting the technical level of regional agriculture. Hence, a further step should be taken in building a more integrated and comprehensive evaluation system to measure cultivated land productivity. In view of this, a comprehensive evaluation of the cultivated land production capacity was carried out in this paper through the effective integration of natural environmental factors and socio-economic and technological factors, taking Yuanjiang city, Hunan province as the study area. The spatial distribution of cultivated land productivity was investigated. A comparative analysis was made between the evaluation of cultivated land productivity, the actual standard food crop yield and the national agricultural land use index to complement the regional cultivated land capacity calculation. This will provide a reference and technical support for the sustainable use of cultivated land resources and greater regional cultivated land production capacity.

2. Data Collection and Analysis

2.1. Survey of Research Area Yuanjiang city is part of Yiyang city in Hunan province, China, located at 112◦1403700 to 112◦5602000 E, and 28◦4202600 to 29◦1101700 N. The city is in the hinterland of the Dongting Lake region, with numerous rivers and lakes. Plains are the main landform. The climate is a subtropical humid monsoon system with abundant sunshine and rainfall. The agricultural system is the standard farming system that is found in the middle and lower reaches of the Yangtze river. At the end of 2015, the total land area of the city was 212,943.82 ha, and the cultivated land was 63,819.03 ha, accounting for 29.97% of the total land area. The cultivated land included 42,985.00 ha of paddy field, 20,779.53 ha of dry land and 54.43 ha of irrigated land. The natural conditions for agricultural resources are favorable, and the soil nutrients are suitable for plant growth (http://www.yuanjiang.gov.cn/c139/index.html). Therefore, Yuanjiang is a nationally important grain and cotton commodity production base.

2.2. Data Collection and Preprocessing The remote sensing data that were used in this paper to obtain the land use and elevation data for Yuanjiang city mainly came from high-resolution remote sensing from Gaofen-1 and GDEMDEM 30 M resolution data in 2016 in the geospatial data cloud (http://www.gscloud.cn/). The slope and topographic data for cultivated land were obtained using ArcGIS 10.1 (The software comes from the American Environmental Systems Research Institute, based in Redlands, California.). Sampling points in this paper were evenly distributed across the area according to fertilization sampling data of Yuanjiang city, the distribution map of agricultural land grade and use, land type, soil type and land use status. Different areas of attributes were classified, and the samples were located by GPS. Altogether, 50 sampling points were chosen (Figure1). The actual latitude and longitude coordinates, the topographic position, the texture of the tillage layer and the structure of the soil were investigated Sustainability 2018, 10, x FOR PEER REVIEW 3 of 15 Sustainability 2018, 10, 3616 3 of 15 latitude and longitude coordinates, the topographic position, the texture of the tillage layer and the structure of the soil were investigated in August 2017. Soil samples were analyzed for physical and in August 2017. Soil samples were analyzed for physical and chemical properties, including total chemical properties, including total nitrogen, organic matter content, pH, available phosphorus, nitrogen, organic matter content, pH, available phosphorus, available potassium and soil bulk density. available potassium and soil bulk density. Data, such as effective soil thickness, type of barrier layer Data, such as effective soil thickness, type of barrier layer and distance from the surface, irrigation and distance from the surface, irrigation guarantee rate and drainage conditions were derived from guarantee rate and drainage conditions were derived from the Yuanjiang agricultural land quality the Yuanjiang agricultural land quality classification data. The level of pest control, irrigation and classification data. The level of pest control, irrigation and flood control standard, agricultural flood control standard, agricultural machinery and equipment, agricultural management and other machinery and equipment, agricultural management and other data were obtained from Hunan province data were obtained from Hunan province rural statistical yearbook (2016), Yuanjiang city statistical rural statistical yearbook (2016), Yuanjiang city statistical yearbook (2016), Yuanjiang city comprehensive yearbook (2016), Yuanjiang city comprehensive agricultural mechanization level summary report (2016) and agricultural mechanization level summary report (2016) and Report on the first national water resources survey Report on the first national water resources survey of Yuanjiang city. The light and temperature of Yuanjiang city. The light and temperature production potential index for different crops in the study production potential index for different crops in the study area was derived from The light and area was derived from The light and temperature (climate) crops in countries and cities in agricultural temperature (climate) crops in countries and cities in agricultural land quality classification rules land quality classification rules (GBT28407-2012). Based on the 2016 Yuanjiang agricultural land quality (GBT28407-2012). Based on the 2016 Yuanjiang agricultural land quality score data, the index for score data, the index for national use of agricultural land, comprehensive land use index, number of national use of agricultural land, comprehensive land use index, number of cultivated land points cultivated land points and other relevant data were obtained, and 18,330 cultivated land points were and other relevant data were obtained, and 18,330 cultivated land points were extracted as the extracted as the evaluation units for cultivated land productivity. All data were preprocessed in the evaluation units for cultivated land productivity. All data were preprocessed in the following ways. following ways. The reliability of the data was verified, and the unity and standardization of the data The reliability of the data was verified, and the unity and standardization of the data were checked. were checked. The data were transformed to a single map projection and coordinate correction was The data were transformed to a single map projection and coordinate correction was carried out for carried out for the map data. The 1980 Xi’an plane coordinate system was used for the coordinate the map data. The 1980 Xi’an plane coordinate system was used for the coordinate system. All data system. All data covered the study area. ArcGIS10.1 software was used to match the data for 16 index covered the study area. ArcGIS10.1 software was used to match the data for 16 index attribute values attribute values to the cultivated land map spots, and a spatial database to evaluate cultivated land to the cultivated land map spots, and a spatial database to evaluate cultivated land productivity in productivity in Yuanjiang city was constructed. Yuanjiang city was constructed.

Figure 1. Distribution of sampling points in the Yuanjiang CityCity studystudy area.area.

2.3.2.3. Analytical Methods 2.3.1. The Definition of Cultivated Land Productivity 2.3.1. The Definition of Cultivated Land Productivity The productivity of cultivated land is a complex system that is affected by the natural environment The productivity of cultivated land is a complex system that is affected by the natural and the social economy, which has both natural and socio-economic properties. The diversity of its environment and the social economy, which has both natural and socio-economic properties. The functions leads to the diversity of cultivated land use [32]. Cultivated land productivity is formed based diversity of its functions leads to the diversity of cultivated land use [32]. Cultivated land on the cultivated land use system and is determined by the quantity and quality of cultivated land. productivity is formed based on the cultivated land use system and is determined by the quantity The quality of cultivated land, which reflects the conditions of light, temperature, precipitation, soil and and quality of cultivated land. The quality of cultivated land, which reflects the conditions of light, Sustainability 2018, 10, x FOR PEER REVIEW 4 of 15 temperature, precipitation, soil and agricultural infrastructure, is the basis of cultivated land productivitySustainability 2018 [33]., 10, Therefore, 3616 cultivated land productivity can be defined as the productivity level4 of 15 that is formed by the interaction and systematic coupling between the cultivated land base, climatic conditions,agricultural farming infrastructure, technology is the level basis and of cultivatedother factors land in productivity a given region [33 ].at Therefore,a given stage cultivated (Figure land 2). Basedproductivity on the concept can be defined of cultivated as the productivityland productivi levelty thatand isfactors formed of byclimate, the interaction cultivated and land systematic quality andcoupling farming between technology the cultivated that affect land productivity, base, climatic an conditions, assessment farming index technologysystem was level constructed, and other whichfactors included in a given three region primary at a given indicators stage (Figure and 162 ).seco Basedndary on theindicators. concept The of cultivated weight of land each productivity index was determinedand factors by of an climate, analytic cultivated hierarchy land process quality (AHP and, farmingTable 1). technologyThe coefficient that of affect cultivated productivity, land qualityan assessment was used index as the system agricultural was constructed, quality score which based includedon the grade three of primarythe agricultural indicators land. and The 16 yieldsecondary ratio coefficient indicators. of The the weight specified of each crop index β and was the determined technical use by level an analytic coefficient hierarchy replaced process the (AHP,land useTable coefficient,1). The coefficient which was of cultivatedthe ratio between land quality crop wasyield used per asunit the area agricultural and the maximum quality score yield based in the on controlthe grade area. of The the agriculturallight and temperature land. The yieldproduction ratio coefficient potential index of the was specified revised crop accordingly.β and the technicalFinally, cultivateduse level coefficientland productivity replaced thewas land calculated, use coefficient, and this which formed was the the data ratio betweenfor the analysis crop yield of perspatial unit differencesarea and the in maximumcultivated yieldland inproductivity the control in area. Yuanjiang The light city and (Figure temperature 3). production potential index was revised accordingly. Finally, cultivated land productivity was calculated, and this formed the data for the analysis ofTable spatial 1. differencesThe evaluation in cultivatedindex system land for cultivated productivity land in productivity. Yuanjiang city (Figure3). Primary Indicator Secondary Indicator Weight Table 1. The evaluation indexLight system and for temperature cultivated landproductivity productivity. potential -- Climate condition Crop yield ratio -- Primary Indicator Secondary Indicator Weight Geological Terrain area 0.50 Light and temperature productivity potential – Climate condition conditions FieldCrop slope yield ratio – 0.50 Effective soil thickness 0.12 Geological Terrain area 0.50 conditions OrganicField slope matter content 0.50 0.11 Cultivated Farming layer texture 0.21 land quality Soil Effective soil thickness 0.12 Cultivated Cultivated ObstacleOrganic mattercourse content type and depth from the surface 0.11 0.04 land quality properties Farming layer texture 0.21 landCultivated land Soil Soil configuration 0.21 Obstacle course type and depth from the surface 0.04 productivity properties productivity SoilSoil bulk configuration density 0.21 0.10 SoilSoil nutrient bulk density element 0.10 0.21 IrrigationSoil nutrient guarantee element rate 0.21 0.16 TheIrrigation drainage guarantee condition rate 0.16 0.30 The drainage condition 0.30 DiseaseDisease and insectinsect pest pest control control level level 0.08 0.08 TillageTillage technology technology FieldField flood flood controlcontrol standard standard 0.07 0.07 AgriculturalAgricultural machinerymachinery and and equipment equipment 0.26 0.26 Agronomic management 0.13 Agronomic management 0.13

FigureFigure 2. 2. TheThe framework framework for for the the evaluation evaluation of of cultivated cultivated land land productivity. productivity. Sustainability 2018, 10, 3616 5 of 15 Sustainability 2018, 10, x FOR PEER REVIEW 5 of 15

Determine the Yuanjiang of cultivated land productivity evaluation system and the weight of indicators

Dividing the evaluation Unit

Data collection and processing of cultivated land productivity evaluation indicators

Light and temperature Crop yield ratio (β ) productivity potential (α )

Coefficient of cultivated Coefficient of tillage land quality (Q ) technology (T)

Cultivated land productivity index (P)

No Grade division and result verification

Yes

Analysis of evaluation results

FigureFigure 3. The 3. The work work flow flow chart chart for for the the evaluation evaluation of of cultivated cultivated land land productivity. productivity.

2.3.2.2.3.2. Calculation Calculation of Cultivated of Cultivated Land Land Productivity Productivity CoefficientCoefficient of cultivated of cultivated land land quality quality The coefficientThe coefficient of cultivated of cultivated land quality land quality was calculated was calculated based on based indexes on ofindexes geological of geological condition and soilcondition properties and insoil each properties evaluation in each unit evaluation using a weighted unit using sum a method.weighted The sum formula method. was The as formula follows: was as follows: n Q = (D × W + T × W ) /100 (1) =∑ i ×1 +i ×2 100 i=1 (1) where Q indicates the coefficient of cultivated land quality of the i unit, D and T indicate the values where indicates the coefficient of cultivated land quality of the i unit,i i and indicate the of indexesvalues of of geological indexes of conditiongeological andcondition soil properties and soil properties for the i unit, for the respectively i unit, respectivelyW1 and W2 indicateand the weightsindicate of the indexes weights of of geological indexes of condition geological and condition soil properties and soil for properties the i unit, for which the i unit, were which 0.2 and were 0.8, respectively0.2 and 0.8,n indicated respectively the numbern indicated of evaluationthe number units. of evaluation units. CoefficientCoefficient of tillage of tillage technology technology The coefficientThe coefficient of tillage of tillage technology technology was was calculated calculated based based on on the the attribute attribute value value ofof eacheach unitunit by the weightedthe weighted sum sum method. method. The The formula formula was was as follows:as follows: n = 100 (2) T = ∑ fiWi /100 (2) i=1

where T indicates the coefficient of tillage technology of the i unit, indicates the standard value of where T indicates the coefficient of tillage technology of the i unit, fi indicates the standard value of the the secondary indicator of the i unit and indicates the weights of the secondary indicator of the i secondaryunit. indicator of the i unit and Wi indicates the weights of the secondary indicator of the i unit. Sustainability 2018, 10, 3616 6 of 15

Cultivated land productivity index Based on the cultivated land quality coefficient and tillage technology coefficient, the index of light and temperature production potential reflecting climatic conditions was modified by gradation Sustainability 2018, 10, x FOR PEER REVIEW 7 of 18 correction to obtain the cultivated land productivity index. The formula was as follows: 푛 n 161 푝 = ∑(α푖 × 훽푖) × 푄p푖 =× ∑푇푖 ( α i × β i ) × Q i × T i (3) (3) i=1 푖=1 162 Where p indicated the cultivated land productivity index of the i unit, α , 훽 , 푄 and 푇 where p indicates the cultivated land productivity index of the i unit, αi, βi, Qi and푖 T푖i indicate푖 the푖 163 indexindicated of light the andindex temperature of light and production temperature potential, production crop yield potential, ratio, cultivatedcrop yield land ratio, quality cultivated coefficient land 164 andquality tillage coefficient technology and coefficienttillage technology of the i unit,coefficient respectively. of the i The unit, cultivated respectively. land The productivity cultivated index land 165 wasproductivity divided index into 15 was classes divided using into 300 15 classes grade spacing.using 300 Thegrade classes spacing. were: The [4200, classes 4500], were: [3900,[4200, 4500], 4200], 166 [3600,[3900, 3900],4200], [3300,[3600, 3600],3900], [3000,[3300, 3300],3600], [2700,[3000, 3300], 3000], [2700, [2400, 3000], 2700], [2400, [2100, 2700], 2400], [2100, [1800, 2400], 2100], [1800, [1500, 2100], 1800], 167 [1200,[1500, 1500], 1800], [900, [1200, 1200], 1500], [600, [900, 900], 1200], [300, 600] [600, and 900], [0, 300]. [300, The 600] cultivated and [0, land 300]. productivity The cultivat indexed land was 168 greatestproductivity at the index class valueswas greatest of [4200, at the 4500], class and values decreased of [4200, until 4500], it reached and decreased the lowest until value it at reached the grades the 169 oflowest [0, 300]. value at the grades of [0, 300].

170 3. Results and Discussiondiscussion

171 3.1.3.1 The The quantitative Quantitative structure Structure of ofcultivated Cultivated land Land productivity Productivity 172 The cultivatedcultivated landland productivity productivity index, index which calculated was calculated by gradation by gradation correction correction, varied from varied 1642.79 from 173 1642.79to 4140.09 to 4140.09,with a range with of a range2499.3. of The 2499.3. quantitative The quantitative breakdown breakdown is shown is in shown Figure in 4. Figure Most 4of. Mostthe land of 174 thewas land located was within located seven within index seven classes: index classes:[3900, 4200], [3900, [3600, 4200], 3900], [3600, [3300, 3900], 3 [3300,600], [3000, 3600], 3300], [3000, [2700, 3300], 175 [2700,3000], 3000],[2100, 2400] [2100, and 2400] [1800, and 2100]. [1800, The 2100]. area The of cultivated area of cultivated land was land the waslargest the in largest the classes in the of classes [3600, 176 of3900], [3600, [3300, 3900], 3600] [3300, and 3600] [2100, and 2400], [2100, which 2400], accounted which accounted for 49,085.03 for ha 49,085.03 (76.91%) ha of (76.91%) the total of cultivated the total 177 cultivatedland area in land the area city. in This the indicates city. This that indicates the cultivated that the cultivated land productivity land productivity index of Yuanjiang index of Yuanjiang city was 178 cityrelatively was relatively concentrated, concentrated, and the cultivated and the cultivatedland of this land city was of this mainly city waslocated mainly between located classes between 2–6. 179 classes 2–6.

7.42% 6.31% [3900,4200) 25.23 [3600,3900) 34.83% [3300,3600) [3000,3300) 9.27% 16.86% [2700,3000) [2100,2400) 0.09% [1800,2100)

Figure 4. The proportion of cultivated land in different land productivity classes. Figure 4. The proportion of cultivated land in different land productivity classes. 180 The cultivated land area for the productivity index of paddy field, located at values of [3900, 4200] 181 (highestThe class)cultivated and [2700, land 3000]area for (lowest the productivity class) were 4020.89 index of ha paddy and 56.26 field, ha, located accounting at values for 9.36% of [3900, and 182 0.13%4200] (highest of the total class) paddy and field[2700, area 3000] in Yuanjiang(lowest class) city, were respectively 4020.89 ha (Table and2 ).56.26 The ha, cultivated accounting land for area 9.36% for 183 theand paddy 0.13% fieldof the productivity total paddy index field locatedarea in atYuanjiang [3600, 3900] city, was respectively the largest, (Table accounting 2). The forcultivated 22,228.28 land ha 184 (51.71%)area for the of the paddy total field paddy productivity field area in index Yuanjiang located city. at The [3600, cultivated 3900] was land the productivity largest, accounting for irrigated for 185 land22,228.28 and dryha (51.71%) land were of boththe total. concentrated The cultivated at values land of [2100,productivity 2400], andfor irrigated the areas la werend and 48.89 dry ha land and 186 16,050.93were both ha, concentrated accounting for at 89.11%values ofand [2100, 77.24%, 2400], respectively. and the areas were 48.89 ha and 16,050.93 ha, 187 accountingThe cultivated for 89.11% land and productivity 77.24%, respectively. indexes for the towns in Yuanjiang city showed great variations (Table3, Figure5). The quantity and structural distribution characteristics of the “inverted pyramid” were present in cultivated land areas of towns at different productivity levels, such as Caowei town, Nanwan Lake, Qianshanhong town, Sijihong town and Yangluozhou town. Their productivity grade for cultivated land was mostly moderate to excellent and at a grade of 2–3. The areas accounted for Sustainability 2018, 10, 3616 7 of 15

41.63%, 53.76%, 58.83%, 37.53% and 47.66%, respectively of the total in these towns. The cultivated land areas at different productivity levels of Chapanzhou town, Gonghua town, Huangmaozhou town, Xinwan town, Luhu reed farm, Nandashan town, Nanzui town, Sihushan town and Wanzi Lake Township showed characteristics of the “dumbbell” structure with two large end values and small middle values. Their cultivated land areas at excellent and low levels accounted for 33.3% and 32.12% of the total, respectively. The quantity and structural distribution characteristics of the cultivated land areas in Qionghu Street, Nandongting Lake reed farm and Qingyunshan Street were “pyramid-shaped” at different productivity levels. The areas at grades from 8 to 9 for cultivated land productivity accounted for 37.89%, 82.32% and 88.87%, respectively. These towns had a greater area of cultivated land at low levels of productivity. The distribution characteristics of the “spindle-type” of quantity structure with two small ends and a large middle were present in the cultivated land area of Sanyantang town at different productivity levels. The cultivated land area at grades of 4–6 accounted for 38.99% of the total in this town.

Table 2. The area and productivity index for different types of cultivated land in Yuanjiang city.

Productivity Index [3900, 4200] [3600, 3900] [3300, 3600] [3000, 3300] [2700, 3000] [2100, 2400] [1800, 2100] Paddy Area (hectare) 4024.89 22,228.28 10,757.33 5918.24 56.26 —— —— field Ratio (%) 9.36 51.71 25.03 13.77 0.13 —— —— Irrigated Area (hectare) —— —— —— —— —— 48.49 5.92 Land land Ratio (%) —— —— —— —— —— 89.11 10.89 type Dry Area (hectare) —— —— —— —— —— 16,050.93 4728.60 land Ratio (%) —— —— —— —— —— 77.24 22.76 Area (hectare) 4024.89 22,228.28 10,757.33 5918.24 56.26 16,099.43 4734.52 Total Sustainability 2018, 10, Ratiox FOR (%) PEER REVIEW 6.31 34.83 16.86 9.27 0.09 25.23 7.42 2 of 18

100% 90% [3900,4200) 80% [3600,3900) 70% 60% [3300,3600) 50% 40% [3000,3300) 30% [2700,3000) 20%

10% [2100,2400)

Qionghu street Qionghu

Nanwanhu street Nanwanhu Qingyunshan street Sanyantang street

Luhu reed field reed Luhu Nandasha town town Nanzui town Wanzihu

Chapanzhou town Gonghua town Huangmaozhou town Nandongtinghu reed reed Nandongtinghu field town Sihushan

Caowei town Qianshanhong Qianshanhong town Sijihong town town Yangluozhou 0% town Xinwan [1800,2100)

208

209 Figure 5 5.. TheThe comparison comparison of cultivated land productivity in different towns.towns.

210 Table 3. The comparison of the technical level of land quality and of climatical condition in same land 211 productivity classes.

Grade section of Technical Cultivated land Climate cultivated land level quality condition productivity index [3900, 4200) 0.99 0.76 1 [3600, 3900) 0.75 0.64 1 [3300, 3600) 0.41 0.56 1 [3000, 3300) 0.02 0.51 1 [2700, 3000) 0 0.15 1 [2100, 2400) 0.54 0.70 0 [1800, 2100) 0.41 0.52 0

212 3.2 Spatial distribution characteristics of cultivated land productivity 213 Based on the spatial distribution of cultivated land productivity, there was a relatively significant 214 difference in the regional distribution in Yuanjiang city, showing a general trend of decreasing from 215 the north to the south and increasing from the middle to the periphery (Figure 6, Figure 7). High 216 quality cultivated lands in the productivity index class of [3900, 4200] were mostly located in the 217 northwest, southwest, northeast and south-central towns in Yuanjiang city, including Caowei, 218 Gonghua, Sanyantang, Nandashan and Sihushan towns, with an area of 3018.3 ha which accounted 219 for 74.99% of the total regional cultivated land area in this index class. At the productivity index grade 220 [3000, 3300], most of the good cultivated lands were located in the northwest, northeast, north and 221 south-central towns, including Caowei, Nandashan, Sihushan and Yangluozhou towns, with an area 222 of 3821 ha, which accounted for 64.56% of the total regional cultivated land area in this index class. 223 At the productivity index grade of [1800, 2100], most of the cultivated lands were located in the north- 224 central, northwest and northeast towns along rivers, including Huangmaozhou, Gonghua, Caowei 225 and Nandashan towns, with an area of 2240.04 ha, which accounted for 47.32% of the total regional 226 cultivated land area in this index class. The cultivated land in these areas was mainly cultivated rice Sustainability 2018, 10, 3616 8 of 15

Table 3. The comparison of the technical level of land quality and of climatical condition in same land productivity classes.

Grade Section of Cultivated Cultivated Land Technical Level Climate Condition Land Productivity Index Quality [3900, 4200] 0.99 0.76 1 [3600, 3900] 0.75 0.64 1 [3300, 3600] 0.41 0.56 1 [3000, 3300] 0.02 0.51 1 [2700, 3000] 0 0.15 1 [2100, 2400] 0.54 0.70 0 [1800, 2100] 0.41 0.52 0

3.2. Spatial Distribution Characteristics of Cultivated Land Productivity Based on the spatial distribution of cultivated land productivity, there was a relatively significant difference in the regional distribution in Yuanjiang city, showing a general trend of decreasing from the north to the south and increasing from the middle to the periphery (Figures6 and7). High quality cultivated lands in the productivity index class of [3900, 4200] were mostly located in the northwest, southwest, northeast and south-central towns in Yuanjiang city, including Caowei, Gonghua, Sanyantang, Nandashan and Sihushan towns, with an area of 3018.3 ha which accounted for 74.99% of the total regional cultivated land area in this index class. At the productivity index grade [3000, 3300], most of the good cultivated lands were located in the northwest, northeast, north and south-central towns, including Caowei, Nandashan, Sihushan and Yangluozhou towns, with an area of 3821 ha, which accounted for 64.56% of the total regional cultivated land area in this index class. At the productivity index grade of [1800, 2100], most of the cultivated lands were located in the north-central, northwest and northeast towns along rivers, including Huangmaozhou, Gonghua, Caowei and Nandashan towns, with an area of 2240.04 ha, which accounted for 47.32% of the total regional cultivated land area in this index class. The cultivated land in these areas was mainly cultivated rice soil, suchSustainability as tidal 2018, mud.10, x FOR The PEER landREVIEW was distributed in the lower part of flat fields and3 of alluvial 18 fields, suffering227 fromsoil, such frequent as tidal waterloggingmud. The land was and distributed with poor in the drainage lower part capacity. of flat fields All ofand these alluvial conditions fields, are not favorable228 suffering for improving from frequent cultivated waterlogging land productivity.and with poor drainage capacity. All these conditions are not 229 favorable for improving cultivated land productivity. Caowei town

Chapanzhou town [1800,2100) Gonghua town

Huangmaozhou town [2100,2400) Qionghu street

Xinwan town

[2700,3000) Luhu reed field

Nandasha town [3000,3300) Nandongtinghu reed field Nanwanhu street

[3300,3600) Nanzui town Qianshanhong town

Qingyunshan street [3600,3900) Sanyantang street

Sijihong town [3900,4200) Sihushan town

0% 20% 40% 60% 80% 100% Wanzihu town 230

231Figure 6. TheFigure comparison 6. The comparison of cultivated of cultivated land land productivity productivity for for different different towns towns in same in index the same class. index class.

232

233

234 Figure 7. Spatial distribution of farmland productivity in Yuanjiang City. Sustainability 2018, 10, 3616 9 of 15 Sustainability 2018, 10, x FOR PEER REVIEW 9 of 15

Sustainability 2018, 10, x FOR PEER REVIEW 4 of 18 FigureFigure 7. 7.Spatial Spatial distributiondistribution of farmland productivity productivity in in Yuanjiang Yuanjiang City. City. 235 Three primary indicators including climate condition, cultivated land quality and tillage ThreeThree primary primary indicators, indicators, includingincluding climate condition, cultivated cultivated land land quality quality and and tillage tillage 236 technology in seven classes of [3900, 4200], [3600, 3900], [3300, 3600], [3000, 3300], [2700, 3000], [2100, technologytechnology in in seven seven classes of of [3900, [3900, 4200], 4200], [3600, [3600, 3900], 3900], [3300, [3300, 3600], 3600], [3000, 3300], [3000, [2700, 3300], 3000], [2700, [2100, 3000], 237 2400) and [1800, 2100] were standardized using range methods. Hence, the data were within the range [2100,2400) 2400) and and[1800, [1800, 2100] 2100] were were standardized standardized using using a range a range of methods. of methods. Hence, Hence, the data the were data within were within the 238 of [0,1], and the average value of the first-level indicators in each section was calculated using the therange range of of[0,1], [0, 1],and and the theaverage average valu valuee of the of first-level the first-level indicators indicators in each in section each sectionwas calculated was calculated using 239 arithmetic mean, to further explore the interaction of various factors and the system coupling effect usingthe thearithmetic arithmetic mean mean to further to further explore explore the theintera interactionction of various of various factors factors and and the the system system coupling coupling 240 on the cultivated land productivity in different classes. From Figure 8 and Table 3, it can be seen that effecteffect on on the the cultivated cultivated land land productivity productivity in in different different classes. classes. From From Figure Figure8 and 8 and Table Table3, it 3, can it can be seenbe 241 the dimensional area of cultivated land productivity decreased from the high class of [3900, 4200] to thatseen the that dimensional the dimensional area of area cultivated of cultivated land productivityland productivity decreased decreas fromed from the highthe high class class of [3900, of [3900, 4200] 242 the4200] medium to the class medium of [2700, class of3000]. [2700, The 3000]. dimensional The dimensional area of area tillage of tillage technology technology decreased decreased the most,the to the medium class of [2700, 3000]. The dimensional area of tillage technology decreased the most, 243 followedmost, followed by that ofby cultivated that of cultivated land quality land qualityand climate and climate condition. condition. However, However, the dimensional the dimensional area of followed by that of cultivated land quality and climate condition. However, the dimensional area of 244 climatearea of condition climate condition significantly significantly decreased decreased, while that wh ofile tillagethat of technologytillage technology and cultivated and cultivated land qualityland climate condition significantly decreased, while that of tillage technology and cultivated land quality 245 graduallyquality incrgraduallyeased whenincreased the cultivatedwhen the landcultivated productivity land productivity index decreased index from decreased the medium from theclass gradually increased when the cultivated land productivity index decreased from the medium class of 246 of [2700,medium 3000] class to of the [2700, low 3000] class toof the [1800, low 2100]. class of [1800, 2100]. [2700, 3000] to the low class of [1800, 2100]. 247

Tillage techonology 1.00 [3900,4200) [3600,3900) 0.50 [3300,3600) [3000,3300) [2700,3000) 0.00 [2100,2400) [1800,2100) Climatic Cultivated land conditions quality

Figure 8. The comparison of cultivated land productivity in different classes. Figure 8. The comparison of cultivated land productivity in different classes.

InIn general, general, the the dominant dominant factors factors influencing influencing the the change change of theof the cultivated cultivated land land productivity productivity index Figure 8. The comparison of cultivated land productivity in different classes. 248 inindex different in different classes varied. classes Whenvaried. the When class the changed class changed from low from to mediumlow to medium levels, climate levels, conditionclimate wascondition the dominant was the factor. dominant When factor. the class When changed the clas froms changed medium from to high medium levels, to tillage high levels, technology tillage and 249 In general, the dominant factors influencing the change of the cultivated land productivity index cultivatedtechnology land and quality cultivated were land the mainquality influencing were the main factors. influencing factors. 250 in different classes varied. When the class changed from low to medium levels, climate condition was 251 the dominant factor. When the class changed from medium to high levels, tillage technology and 252 cultivated land quality were the main influencing factors.

253 3.3 Comparative analysis of cultivated land productivity index and national use index 254 The quantitative structure, spatial distribution and linear correlation between the cultivated land 255 productivity index and the national use index of agricultural land quality were compared and 256 analyzed (Figure 9). The cultivated land area in the productivity classes of [4200, 4500], [3900, 4200] 257 and [3600, 3900] was 26,253.17 ha, accounting for 41.14% of the total. Most of the agricultural 258 cultivated land was located in the national use index classes of [2800, 3000], [2600, 2800] and [2400, 259 2600], which covered 60,227.02 ha (94.37%) of the total area. The cultivated land area in productivity 260 classes of [2700, 3000], [2100, 2400] and [1800, 2100] was 20,890.21 ha, accounting for 32.74% of the 261 total. However, no agricultural cultivated land was located in other national use index classes. 262 Compared with the agricultural cultivated lands in different use index classes, cultivated lands in 263 different productivity classes showed a scattered distribution pattern, with the characteristics of a 264 "dumbbell" structure. However, the distribution of agricultural cultivated lands in different use index 265 classes was relatively concentrated, presenting the quantitative structure distribution of an "inverted 266 pyramid". 267 Sustainability 2018, 10, 3616 10 of 15 Sustainability 2018, 10, x FOR PEER REVIEW 10 of 15

3.3.3.3. Comparative Comparative Analysis Analysis of of Cultivated Cultivated LandLand ProductivityProductivity Index Index and and National National Use Use Index Index TheThe quantitative quantitative structure, structure, spatialspatial distributiondistribution and and linear linear correlation correlation between between the the cultivated cultivated landland productivity productivity index index and and the the national national useuse indexindex of of agricultural agricultural land land quality quality were were compared compared and and analyzedanalyzed (Figure (Figure9). 9). The The cultivated cultivated land land areaarea inin thethe productivityproductivity classes classes of of [4200, [4200, 4500], 4500], [3900, [3900, 4200] 4200] andand [3600, [3600, 3900] 3900] was was 26,253.17 26,253.17 ha, accountingha, accounting for 41.14% for 41.14% of the of total. the Mosttotal. of Most the agriculturalof the agricultural cultivated landcultivated was located land was in thelocated national in the use national index use classes index ofclasses [2800, of 3000],[2800, 3000], [2600, [2600, 2800] 2800] and [2400,and [2400, 2600], which2600], covered which 60,227.02covered 60,227.02 ha (94.37%) ha of(94.37%) the total of area.the total The area. cultivated The cultivated land area inland the area productivity in the classesproductivity of [2700, classes 3000], [2100,of [2700, 2400] 3000], and [2100, [1800, 2400] 2100] and was [1800, 20,890.21 2100] ha, was accounting 20,890.21 for ha, 32.74% accounting of the for total. However,32.74% of no the agricultural total. However, cultivated no agricultural land was cultivated located in land other was national located use in other index national classes. use Compared index withclasses. the agriculturalCompared with cultivated the agricultural lands in cultivated different uselands index in different classes, use cultivated index classes, lands cultivated in different productivitylands in different classes showed productivity a scattered classes distribution showed pattern,a scattered with thedistribution characteristics pattern, of awith “dumbbell” the characteristics of a “dumbbell” structure. However, the distribution of agricultural cultivated lands structure. However, the distribution of agricultural cultivated lands in different use index classes was in different use index classes was relatively concentrated, presenting the quantitative structure relatively concentrated, presenting the quantitative structure distribution of an “inverted pyramid”. distribution of an “inverted pyramid”.

30695.71 One grade 16279.82 4024.89 Two grade 13251.49 22228.28 Three grade

2704.43 10757.33 Four grade 887.51 5918.24 Five grade

56.26 Six grade

16099.43 Eight grade 4734.52 Nine grade

35000 25000 15000 5000 5000 15000 25000 35000 Agricultural land national utilization index

Figure 9. The comparison of the cultivated land area in the productivity index and in the national Figure 9. The comparison of the cultivated land area in the productivity index and in the national land land use index. use index.

AccordingAccording to to the the spatial spatial distribution distribution characteristicscharacteristics of of cultivated cultivated land land in in different different classes, classes, lands lands with productivity indexes in the high classes of [4200, 4500] and [3900, 4200] (grades 1 and 2) were with productivity indexes in the high classes of [4200, 4500] and [3900, 4200] (grades 1 and 2) mostly distributed at the northwest, north-central, northeast, southwest and south-central towns in were mostly distributed at the northwest, north-central, northeast, southwest and south-central Yuanjiang city, including Caowei, Gonghua, Huangmaozhou, Nandashan, Sanyantang and towns in Yuanjiang city, including Caowei, Gonghua, Huangmaozhou, Nandashan, Sanyantang Sihushan towns, with an area of 3018.3 ha, which accounted for 74.99% of the total (Figures 6 and and Sihushan towns, with an area of 3018.3 ha, which accounted for 74.99% of the total (Figures6 10). The agricultural cultivated lands in the national use index classes of [2800, 3000] and [2600, 2800] and(grades 10). 1 The and agricultural 2) were mostly cultivated located at lands the northw in theest, national north and use northeast index classes towns, including of [2800, Caowei, 3000] and [2600,Gonghua, 2800] Huangmaozhou, (grades 1 and 2) Nandashan were mostly and located Luoyangzhou at the northwest,towns, with north an area and of northeast 31,837.24 towns,ha, includingwhich accounted Caowei, Gonghua,for 67.77% Huangmaozhou,of the total. In the Nandashanlow cultivated and land Luoyangzhou productivity towns,index class with of an [1800, area of 31,837.242100], lands ha, which were accountedmostly locate ford 67.77% at the ofnorthwest, the total. central-west In the lowcultivated and northeast land towns, productivity including index classCaowei, of [1800, Gonghua 2100], and lands Nandashan were mostly towns, located with an at area the northwest,of 2240.04 ha, central-west which accounted and northeast for 47.32% towns, of includingthe total. Caowei, Similarly, Gonghua in the lower and classes Nandashan of the agricultural towns, with cultivated an area land of 2240.04 national ha, use which index at accounted [2000, for2200], 47.32% most of theof the total. lands Similarly, were located in the at lowerthe nort classeshwest, of north the agriculturaland northeast cultivated towns, including land national Caowei use indexand atGonghua [2000, 2200],towns, most with ofan thearea lands of 770.62 were ha, located which ataccounted the northwest, for 86.83% north of the and total. northeast In general, towns, includingthe spatial Caowei distribution and Gonghua trend of towns, cultivated with land an area in the of 770.62 relatively ha, whichhigh classes accounted of the for productivity 86.83% of the total.index In general,and the national the spatial use distribution index of agricultural trend of cultivated land were land relatively in the relativelyconsistent, high except classes that ofthe the productivitycoverage was index different. and the national use index of agricultural land were relatively consistent, except that the coverage was different. Sustainability 2018, 10, x FOR PEER REVIEW 6 of 18 Sustainability 2018, 10, 3616 11 of 15 Sustainability 2018, 10, x FOR PEER REVIEW 11 of 15

290

291 Figure 10. Spatial distribution of different levels of the national land use index in Yuanjiang City. FigureFigure 10. 10.Spatial Spatial distribution distribution ofof differentdifferent levels of th thee national national land land use use index index in in Yuanjiang Yuanjiang City. City.

292 CorrelationsCorrelationCorrelations were were were analyzed analyzedanalyzed between betweenbetween the thethe annual annual standard standard crop crop yield, yield, the the cultivated cultivated land land 293 productivityproproductivityductivity index index and and and the the the national national national use useuse index indexindex of of agricultural agricultural cultivatedcultivated cultivated landland land (Figure(Figures (Figures 11 11, 11Figureand and 12). 1212 ).). 294 AnnualAnnual standard standard crop crop crop yield yieldyield was waswas calculated calculated basedbased based on on thethe the actualactual actual yields yields yields of of different ofdifferent different crop crop cropspecies. species. species. A A 295 Asignificantsignificant significant positive positive positive correlation correlation correlation waswas was determineddetermined determined between between annual ann annualual standard standard standard crop crop crop yield yield yield and and the the productivity index and national use index, with R2 values of 0.7775 and 0.5422 and correlation 296 productivity index and national use index, with R2 valuesvalues of of 0.7775 0.7775 and and 0.5422, 0.5422 and correlation coefficients of 0.8817 and 0.7363, respectively. The linear regression model performed better with the 297 coefficientscoefficients of 0.8817 and 0.7363, respectively. The linear regression model performed better with the annual standard crop yield and productivity index, implying that the results that were obtained 298 annual standard standard crop crop yield yield and and productivity productivity index, index, implying implying that that the results the results that were obtained obtained from from the from the evaluation of cultivated land productivity better reflect the production capacity of local 299 theevaluation evaluation of cultivated of cultivated land land productivity productivity can betterbetter reflectreflect thethe productionproduction capacitycapacity ofof locallocal crops.crops. 300 crops. 2000 y = 0.4705x - 203.59 R² = 0.7775 1600

1200 ）

800 (kg/mu 400

Annual standard crop yield crop standard Annual 0 2000 2500 3000 3500 4000 4500

301 Cultivate land productivity Figure 11. The scatter plot of the cultivated land productivity index and the surrounding standard 302 Figuregrain 11.11 output.. The scatter plot of the cultivated land productivity index and the surroundingsurrounding standard grain output. 303 grain output. Sustainability 2018, 10, 3616 12 of 15 Sustainability 2018, 10, x FOR PEER REVIEW 7 of 18

2100 y = 1.3835x - 2459.9 1800 R² = 0.5422

1500

1200

(kg/mu) 900

600 Annual standard crop crop yield standard Annual 300 2200 2400 2600 2800 3000 3200 3400 National utilization index 304 Figure 12. The scatter plot of the national land use index and the surrounding standard grain output. 305 Figure 12. The scatter plot of the national land use index and the surrounding standard grain output 4. Discussion and Conclusions 306 4. Discussion and conclusions 4.1. Discussion 307 4.1 Discussion The cultivated land use system is a complex system of human and natural processes that is 308 affectedThe by cultivated natural environmental land use system factors is a andcomplex socio-economic system of human factors. and The natural results ofprocesses the cultivated that is 309 landaffected productivity by natural showed environmental that it was factors both and comprehensive socio-economic and ablefactors. to dealThe withresults complexity. of the cultivated In fact, 310 theland cultivated productivity land showed production it was capacity both comprehensive reflects the cultivated and able landto deal productivity with complexity. level and In fact, output the 311 effect,cultivated which land is production greatly affected capacity by landreflects potential, the cultivated climate land condition productivity and labor level condition. and output On effect, one 312 hand,which theis greatly evaluation affected result by of land cultivated potential, land climate productivity condition needs and tolabor reflect condition. the productivity On one hand, level the of 313 cultivatedevaluation landresult under of cultivated the co-constraint land productivity conditions needs of natural to reflect and the soil productivity factors. On level the of other cultivated hand, 314 itland needs under to reflect the co the-constraint constraint conditions of human managementof natural and measures soil factors. on the On productivity the other levelhand, of it cultivated needs to 315 land.reflect The the difficulty constraint of of the human evaluation management of cultivated measures land productivityon the productivity lies in the level indexes of cultivated selection land. and 316 quantitativeThe difficulty measurement of the evaluation based onof cultivated three core conceptsland productivity of geological lies condition, in the indexes soil character selection and and 317 tillagequantitative technology. measurement This paper based focused on three on the core evaluation concepts and of geological comparative condition, analysis soil of cultivated character landand 318 productivitytillage technology. in a specific This paper period focused and a specificon the evaluation region. However, and comparative the time scale analysis variation of cultivated of cultivated land 319 landprodu productivityctivity in a specific and the period sensitivity and ofa specific index weight region. were However, involved. the Atime further scale breakthroughvariation of cultivated needs to 320 beland made productivity in the subsequent and the researchsensitivity on of the index accumulation weight were of multi-source been involved. data A and further methods. breakthrough 321 needsDue to be to made the mismatch in the subsequent of data sources research and on the accumula inconsistencytion of of multi weights-source and data methods and methods. in most 322 evaluationDue to research, the mismatch it is often of data difficult sources to avoid and thethe discrepancyinconsistency between of weights the descriptions and methods of thein most real 323 situationevaluation of research, the region it andis often the evaluationdifficult to results.avoid the In discrepancy this paper, we between believe the that descriptions subjective weightingof the real 324 issituation better than of the objective region and weighting the evaluation on the calculationresults. In this of indexpaper, weight. we believe This that is duesubjective to the weighting results of 325 entropyis better valuethan objective method, weighting which is mainly on calculation affected byof index data with weight. larger This variation, is due to based the results on the of principle entropy 326 invalue reflecting method the which difference is mainly between affected indicators. by the However,data with itlager can variation be found, thatbased not on every the principle index with in 327 greatreflecting variations the difference is important between for theindicators. evaluation However, of the it cultivated can be found land that productivity not every index which with involves great 328 multiplevariations indexes. is important Therefore, for it evaluation is necessary the to cultivated make index land weight productivity control with which subjective involves judging. multiple 329 indexes.The Therefore, level of demand it is nec foressary cultivated to make land index productivity weight control is changing with subjective with rapid judging. socio-economic 330 development,The level from of demand the initial for pursuit cultivated of high land yield, productivity stable production is changing to ecological, with rapid safe andsocio sustainable-economic 331 production.development, With from the the progress initial of pursuit science of and high technology, yield, stable modern production agricultural to ecological, infrastructure safe andhas 332 beensustainable improved production. and advanced With agricultural the progress technology of science has been and gradually technology, popularized modern and agricultural applied. 333 Ininfrastructure different development has been stages, improved the influence and advanced of single agriculturalfactor or multiple technology factor coupling has been on cultivated gradually 334 landpopularized productivity and applied. is changing. In different Therefore, development future research stages, should the influence focus on of how single to comprehensivelyfactor or multiple 335 considerfactor coupling the impact on cultivated of various land factors productivity on cultivated is changing. land productivity, Therefore, future and further research optimizing should focus the 336 evaluationon how to indexcomprehensively framework, classificationconsider the impact method of and various valuation factors rules on to cultivated build a practical land productivity, evaluation 337 systemand further for cultivated optimize landthe evaluatio productivity.n index framework, classification method and valuation rules, to 338 build a practical evaluation system for cultivated land productivity. Sustainability 2018, 10, 3616 13 of 15

4.2. Conclusions This paper constructed a comprehensive evaluation index of cultivated land productivity and, using a set of cultivated land points, carried out an empirical analysis of the production capacity of cultivated land from the multidimensional perspectives of the quantitative structure of cultivated land productivity, spatial differentiation and comparison with national use indexes. Yuanjiang city was used as the research area. The conclusions were as follows. First, Yuanjiang city had a productive natural environment and good farming conditions. The cultivated land productivity index ranged from 1642.79 to 4140.09 and was concentrated in classes from 2 to 6. Different land types varied in terms of cultivated land productivity index, and paddy field was better than dry land and irrigated land. The cultivated land productivity index of different towns presented four kinds of quantitative structure distributions, namely the “inverted pyramid”, “dumbbell”, “pyramid-shaped” and “spindle-type”. Second, the regional distribution of cultivated land productivity in Yuanjiang city showed a pattern of variation, with a spatial distribution trend of decreasing from north to south and increasing from the center to the periphery. The cultivated lands with relatively high productivity were mainly distributed in the northwest, southwest, northeast and south-central areas of Yuanjiang city. The dominant factors that were influencing the variation of the cultivated land productivity index were different in different classes. When the class changed from low to medium, climate condition factors were most important, while when the classes changed from medium to high, tillage technology and cultivated land quality were dominant. Finally, cultivated lands in different productivity classes were scattered, showing the distribution characteristics of a “dumbbell” quantity structure. However, the distribution of agricultural cultivated lands in different use index classes was relatively concentrated, showing the quantitative structure distribution of an “inverted pyramid”. The spatial distribution trend of cultivated land in the higher value classes of the productivity index and the national use index of agricultural land were relatively consistent, except that the coverage was different. According to the correlation analysis, the results that were obtained from the evaluation of cultivated land productivity reflect the production capacity of local crops better than those from the evaluation of the national use of agricultural cultivated land.

Author Contributions: Funding acquisition, Y.Z.; methology, X.L.; investigation, P.X.; writing-original draft preparation, C.Z., X.L. and J.J.; writing-review and editing, C.Z. and X.L. Funding: This research was funded by the National Natural Science Foundation of China, grant number 41271534; This research was funded by self-determined research funds of Central China Normal University, grant number CCNU18TS023 and CCNU15A05008. Conflicts of Interest: The authors declare no conflict of interest.

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