A Study on the Arable Land Demand for Food Security in China

sustainability

Article A Study on the Arable Land Demand for Food Security in China

Aiqi Chen 1,2, Huaxiang He 3 , Jin Wang 1,2, Mu Li 1,2, Qingchun Guan 1,2 and Jinmin Hao 1,2,*

1 College of Land Science and Technology, China Agricultural University, Beijing 100193, China 2 Key Laboratory of Agricultural Land Quality, Ministry of Natural Resources of the People’s Republic of China, Beijing 100193, China 3 State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China * Correspondence: [email protected]

Received: 23 July 2019; Accepted: 29 August 2019; Published: 1 September 2019

Abstract: Food security is the basis of social stability and development. Maintaining sufficient amounts of arable land is essential for China’s food security. In this paper, we consider the relationship between arable land demand to grain demand and production capacity. The changes in national population, grain production, and consumption from 2000 to 2015 are analyzed. Then, we forecast the respective possible changes in the future and accordingly forecast the arable land demand in different possible situations. The results show that the pressure to maintain sufficient amounts of arable land in 2030 may be greater than that in 2040.The higher pressure is due to larger population and lower production capacity. To ensure food security in China, we insist on maintaining 120 million ha of arable land, the “red line” for food security, and improve the arable land productivity to ensure domestic production and self-sufficiency. In addition, residents should be guided to cultivate sound food consumption habits in order to control per capita grain demand. Lastly, we should also make full use of international resources and markets to relieve the pressure on domestic resources and environments.

Keywords: arable land demand; grain demand; grain production; food security; China

1. Introduction China’s food security has been a global issue, especially since the publication of Lester K. Brown’s book, “Who Will Feed China?” [1]. China is the most populous country with only 7% of the arable land in the world to feed about 19% of the population. People all over the world focus on the problem of food security in China. In recent years, grain production in China has increased significantly, as has the grain import. Figure1a shows that the output of grain from 2000 to 2003 fluctuated within a tight range and increased year after year until 2015 by an average growth rate of 3.13%. Figure1b shows that grain imports rose sharply in 2003, when China became a net importer. This also means that the grain self-sufficiency ratio of China has been declining.

Sustainability 2019, 11, 4769; doi:10.3390/su11174769 www.mdpi.com/journal/sustainability Sustainability 2019, 11, 4769 2 of 15 Sustainability 2019, 11, 4769 2 of 15

106 tons 6 10 tons % 106 tons 800 12 800 12 120

8 600 90

4 60 400 0 30 200 -4 0 0 -8 Year

0 -8 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2000 2002 2004 2006 2008 2010 2012 2014 Year -30 Grain production Growth rate Net import Import Export Grain production Growth rate Net import Import Export (a) Grain production (b) Grain import and export

Figure 1.ChangesChanges in in grain grain production production and and trade trade in in China China from from 2000 2000 to to 2015. 2015.

Arable land is an an essential essential part part of of land land resources, resources, directly directly affects aﬀects the the food food security security of of any any region. region. The amount ofof arablearable landland inin China, China, especially especially the the high-quality high-quality arable arable land, land, has has decreased decreased because because of ofrapid rapid urban urban expansion, expansion, adjustments adjustments in agriculture, in agriculture, natural natural disasters, disasters, and soand on. so According on. According to China to Chinaland and land resources and resources statistical statistical yearbooks, yearbooks, more than more 75% than of the75% reduction of the reduction of arable of land arable is annually land is annuallyoccupied occupied for the nonagricultural for the nonagricultural construction. construction. Figure2 shows Figure that 2 the shows arable that land the area arable decreased land area by decreased385.9 thousand by 385.9 ha from thousand 2009 to ha 2015. from According 2009 to 2015. to the Ac graincording yield to the per grain unit area yield in per 2015, unit 2.1 area million in 2015, tons 2.1of grainmillion was tons lost, of which grain couldwas lost, feed which 4.2 million could residents.feed 4.2 million According residents. to the According results of the to the Investigation results of theand Investigation Assessment of and Arable Assessment Land Quality of Arable Grade Land in China Quality in 2015, Grade the in high-quality China in 2015, arable the land high-quality accounts arablefor 29.47% land and accounts the rest, for more 29.47% than and two-thirds the rest, of arablemore than land, two-thirds is low-and medium-quality.of arable land, is Therefore, low-and medium-quality.faced with an increasing Therefore, population, faced with increasing an increa grainsing demand, population, and decreasingincreasing andgrain not demand, high-quality and decreasingarable land, and more not attention high-quality should arable be paid land, to more arable attention land protection should be and paid long-term to arable food land security. protection It is andkey tolong-term protect thefood quantity, security. quality, It is key and to protect ecology th ofe quantity, arable land. quality, As a and popular ecology Chinese of arable saying land. goes, As athe popular Chinese Chinese should saying hold thegoes, rice the bowl Chinese ﬁrmly should in our hold own the hands rice and bowl protect firmly arable in our land own justhands as theyand protect thearable panda. land Therefore, just as they the Chinese protect government the panda. should Therefore, establish the andChinese adhere government to the strictest should rules establishfor protecting and adhere and economizing to the strictest arable rules land. for protecting and economizing arable land.

106 Ha 135.5 135.4 135.3 135.2 135.1 135 134.9 134.8 Year 2009 2010 2011 2012 2013 2014 2015 Year Arable land area Arable land area Figure 2.ChangesChanges in in the the area area of of arable arable land land in in China China from from 2009 2009 to to 2015. 2015.

Arable landland isis fundamental fundamental for for food food production. production. Recently, Recently, relevant relevant international international research research mostly mostlyfocuses focuses on land on requirements land requirements for food. for According food. According to a historical to a historical analysis, analysis, the developments the developments in the inland the requirements land requirements for food for infood the in Philippines the Philippines are non-linear are non-linear [2]. The [2].The population population that that a region a region can canhold hold is closely is closely related related to the arableto the land arable area, land production area, production capacity, and capacity per capita, and food perconsumption. capita food consumption. Much research shows that in the future the changes of the food consumption patterns may have a greater influence on the land requirements for food than the population and it is same in Sustainability 2019, 11, 4769 3 of 15

Much research shows that in the future the changes of the food consumption patterns may have a greater influence on the land requirements for food than the population and it is same in China [3–5]. Hence, more and more research focuses on the changes of land requirements for food affected by food consumption patterns. Different diets may result in different land requirements for food. For an affluent diet, 60–80% more land is required than for a basic diet [6]. The consumption of animal products has an important influence on the land requirements for land. In the UK, more than 70% of the land requirements for food are related to the consumption of animal products [7]. Increasing meat in the diet results in increasing per capita land requirements [8]. Various factors affect land requirements for meat production and different meat production by pigs and beef cattle also have different land requirements [9]. Generally, when an economy grows, per capita food consumption changes [10]. The change, which is characterized by less direct grain consumption and more indirect grain consumption (i.e., animal food consumption), is happening in China. This requires China to maintain an adequate amount of arable land in order to achieve the goal of a good harvest and to ensure food security. However, what is the adequate amount? Relevant research attracts much attention from the scholars. Some researchers have analyzed and predicted arable land demand at different scales in all of China [11,12], in a province [13,14], in a city [15–17], or in a county [18,19]. In the existing studies, the main methods have included mathematical models such as the Gray-Markov combinatorial model and methods based on different objectives, such as the demand of different departments, i.e., food security, the sustainable development of regional society, economy, ecology, and even multiple objectives [20,21]. Furthermore, some scholars used several methods at the same time, analyzed the results, and then drew conclusions [22]. Some scholars particularly analyzed changes in residents’ dietary patterns and took into account those possible changes while forecasting arable land demand [23,24]. However, international grain trade liberalization makes it possible to properly import grain for forage and industry currently. The existing research does not consider the situation in which the social economy, agricultural production, the people’s diet, and domestic and international markets vary constantly. China is about to optimize its national territory spatial planning. It is one of the important contents to forecast arable land demand in this planning. In this study, we forecast the amount of arable land we must protect for food security in China in 2030 (short term) and 2040 (long term).

2. Materials and Methods

2.1. Data We used the available data in China statistical yearbooks, the platform for sharing the results of the second National Land Resource Survey of China, China’s land and resources statistical yearbooks from 2001 to 2016, the results of the Investigation and Assessment of Arable Land Quality Grade in China in 2015 and Chinese agricultural development reports in 2016. The data include grain yield, grain imports and exports, arable land quantity and quality, per capita consumption of major foods, population, grain yield per unit area, crops, and grain sown area. Based on the caliber of the statistics available, the grain in this study includes cereals (rice, wheat, corn and so on), beans, and tubers.

2.2. Methods Arable land demand depends on the aggregate grain demand and the arable land productivity. The aggregate grain demand, which must be produced domestically, is related to the population size, per capita grain demand, and self-suﬃciency ratio. The arable land productivity is related to the grain yield per unit area, the multiple cropping index and crop planting structure. Based on the above analysis, the detailed formula is as follows:

S = (A Gp P)/(E R U) (1) × × × × Sustainability 2019 11 Sustainability 2019, 11,, 4769 4 of4 of 15 15 where S is the arable land demand. A is the grain self-sufficiency ratio. Gpis per capita grain demand. where S is the arable land demand. A is the grain self-suﬃciency ratio. Gp is per capita grain demand. P is the national population. E is the multiple cropping index. R is the ratio of grain to crop sown P is the national population. E is the multiple cropping index. R is the ratio of grain to crop sown area. area. U is grain yield per unit area. U is grain yield per unit area. The methods and results of predicting the above six factors are as follows. The methods and results of predicting the above six factors are as follows.

2.2.1. Population Population China is the most populous country. Figure 33 showsshows thatthat thethe populationpopulation inin ChinaChina hashas increasedincreased year after year. China had a population of 1.375 billion in 2015, which was approximately 0.1 billion more thanthan inin 2000. 2000. Therefore, Therefore, over over the the past past 15 years,15 years, the nationalthe national population population has achieved has achieved an annual an annualincrease increase of 7 million of people.7 million However, people. the However, population the growth population rate has growth ﬂuctuated rate signiﬁcantly,has fluctuated but significantly,overall, it has but declined. overall, it has declined.

Billion % 1.40 0.8

0.7 1.36 0.6 1.32 0.5

1.28 0.4

0.3 1.24 0.2 1.20 0.1

1.16 0.0 Year Population Growth rate

Figure 3.ChangesChanges in in the the national national population population and and its its growth growth rate rate from from 2000 2000 to to 2015. 2015. Why has this fluctuation occurred? Over the past few years, with the rapid development of Why has this fluctuation occurred? Over the past few years, with the rapid development of the the social economy, the levels of urbanization, healthcare, and education continue to increase, which social economy, the levels of urbanization, healthcare, and education continue to increase, which all all affects the national population. Specifically, while the economy develops and residents’ incomes affects the national population. Specifically, while the economy develops and residents’ incomes increase, more people are willing to have more babies. On the other hand, though, the stress from work, increase, more people are willing to have more babies. On the other hand, though, the stress from the rising home prices, and cost of education restrain some people from having children, especially work, the rising home prices, and cost of education restrain some people from having children, low-and middle-income earners. As the cultural and educational level rises, the average marriage especially low-and middle-income earners. As the cultural and educational level rises, the average age increases and eugenics receive more attention. Some people are more willing to spend their marriage age increases and eugenics receive more attention. Some people are more willing to spend limited income on limited kids and to raise them to be excellent. Moreover, advances in medical their limited income on limited kids and to raise them to be excellent. Moreover, advances in technology have also undoubtedly directly affected the birth and death rates. Thus, it can be seen that medical technology have also undoubtedly directly affected the birth and death rates. Thus, it can the population is affected by many factors. be seen that the population is affected by many factors. Many scholars and institutions have analyzed and predicted China’s population prospects. Many scholars and institutions have analyzed and predicted China’s population prospects. Most results show that the population will peak around 2030, at which point the population should Most results show that the population will peak around 2030, at which point the population should actually begin to decrease [12,25–27]. The National Population Development Plan (2016–2030) predicts actually begin to decrease [12,25–27].The National Population Development Plan (2016–2030) that the population of China will peak at 1.45 billion in 2030 and then will fall steadily [25]. The 2019 predicts that the population of China will peak at 1.45 billion in 2030 and then will fall steadily [25]. Revision of World Population Prospects predicts China will have 1.464 billion residents in 2030 and The 2019 Revision of World Population Prospects predicts China will have 1.464 billion residents in 1.449 billion in 2040 [26]. In this study, we choose the results in the 2019 Revision of World Population 2030 and 1.449 billion in 2040 [26]. In this study, we choose the results in the 2019 Revision of World Prospects by the Population Division of the Department of Economic and Social Affairs of the United Population Prospects by the Population Division of the Department of Economic and Social Affairs Nations Secretariat as the prediction of the national population. of the United Nations Secretariat as the prediction of the national population.

2.2.2. Per Capita Grain Demand Previous research has shown that in the near future changes in food consumption patterns rather than population growth would be the most important variable for total land requirements for Sustainability 2019, 11, 4769 5 of 15

2.2.2. Per Capita Grain Demand

SustainabilityPrevious 2019 research, 11, 4769 has shown that in the near future changes in food consumption patterns5 of rather 15 than population growth would be the most important variable for total land requirements for food [28]. Infood China, [28]. the In changes China, the are apparentchanges are (Figure apparent4). By (Figure comparison, 4). By comparison, the diet of rural the diet people of rural is di ﬀpeopleerent fromis thatdifferent of urban from people. that of The urban grain people. consumption The grain of consumption rural people of is rural much people higher is than much that higher of urban than people,that althoughof urban it people, is decreasing. although The it is consumption decreasing. The of aquatic consumption products, of aquatic meat, eggs,products, milk, meat, and soeggs, on milk, of rural peopleand so is on much of rural lower people than is that much of urbanlower people,than that although of urban itpeople, is increasing. although At it theis increasing. national level,At the the meatnational consumption level, the in meat 2015 consumption is 1.7 times as in much2015 is as 1.7 that times in 2000. as much Generally, as that with in 2000. the rapidGenerally, urbanization with the rapid urbanization in China, per capita grain consumption is declining and animal food in China, per capita grain consumption is declining and animal food consumption is increasing, which consumption is increasing, which means that the grain for animal feed and the total grain means that the grain for animal feed and the total grain consumption are both increasing. consumption are both increasing.

Grain/kg Others/kg 280 70

240 60

200 50

160 40

120 30

80 20

40 10

0 0 Year 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Grain Aquatic Products

Meat（Pork，Beef，Mutton and Poultry） Eggs

Milk and Dairy Products Fresh Melons and Fruits (a) Rural

Grain/kg Others/kg 280 70

240 60

200 50

160 40

120 30

80 20

40 10

0 0 Year 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Grain Meat（Pork，Beef，Mutton and Poultry） Aquatic Products Eggs Milk and Dairy Products Fresh Melons and Fruits (b) Urban

FigureFigure 4. 4.ChangesChanges in in per per capita capita consumption consumption of of major major foods foods in ruralin rural( (a) anda) and urban urban( (b)b households) households from 2000from to 2000 2015. to 2015.

The changes, especially meat consumption, draw some scholars’ attention. Zhang et al. thinks the recent trend of rising income may lead to increased meat consumption in the near future [29]. Chao et al. predicts that per capita meat consumption will increase to 85 kg per year in 2030 and more than 100 kg per year in 2040, which is still lower than that in some western developed countries [30]. However, it is not necessarily, as the dietary pattern in China has long been different from other western countries. The Chinese Dietary Guidelines recommend that meat consumption should be 40–75 g per capita per day. More and more Chinese people also recognize that eating too much meat could lead to some diseases, such as obesity and cardiovascular disease. Besides, some scholars predict the grain demand for different uses. They analyze and predict per capita grain demand and their outcomes differ from each other because of the different models and parameters they use. Xin et al. predicts that the demand for food and feed grain will be 386.5 kg per capita per year in 2030, which is driven by dietary structure changes, and 551.4 kg per capita per year including industrial use, seed use, and wastage [31]. Li et al. predict that it will be 421.4 kg per capita per year for food and feed use and 546.3 kg per capita per year in total [32]. Lu thinks every person needs 400 kg of grain per year in total for subsistence and 400–600 kg for a fairly prosperous life [33]. Chen predicts that the grain demand per capita, based on the differences in nutrition supply at moderately prosperous and prosperous levels is 450 kg and 500 kg per year, respectively [34]. Considering all of the above, we predict that the total grain demand will be 420 kg, 500 kg, and 550 kg per capita per year, respectively, for subsistence, moderately prosperous, and prosperous levels in the future. Moreover, 500 kg per capita per year is regarded as the demand for a nutritious diet [35].

2.2.3. Grain Self-Sufficiency Ratio The grain self-sufficiency ratio is an important indicator for measuring the degree of national food security. It is generally believed that a grain self-sufficiency ratio of more than 1 means full self-sufficiency, between 0.95 and 1 means high self-sufficiency, between 0.9 and 0.95 means basic self-sufficiency, and less than 0.9 means the risk will increase. The grain self-sufficiency ratio is the ratio of grain produced by a country or a region to grain demand. Grain demand can be calculated by grain production, import, export, and storage. As it is difficult to obtain data on grain storage, grain storage is assumed to be stable or little changed. Because of the caliber of the statistics in China, the grain in this study includes cereals (rice, wheat, corn, and so on), beans, and tubers. The Food and Agriculture Organization (FAO) of the United Nations usually counts cereal, which is international. Therefore, in this section, we also analyze the cereal self-sufficiency ratio to determine the degree of staple grain self-sufficiency, which is more comparable internationally. Cereals here mainly include wheat, rice, and corn. However, it is clear that even if the self-sufficiency ratios that are calculated are inconsistent because they are based on statistics of varying calibers, they essentially reflect the status of dependence on external grain and food security in China. Figure5 shows that the grain self-su fficiency ratio declined from 2000 to 2015 and has been less than 0.90 since 2012. In other words, grain security has been somewhat put at risk. Additionally, the cereal self-sufficiency ratio was more than 0.98, even though it was decreasing. We have maintained high cereal self-sufficiency since 2000. Sustainability 2019, 11, 4769 7 of 15 Sustainability 2019, 11, 4769 7 of 15

1.1

0.9

0.8

0.7 Year 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Grain Cereal Note: Grain includes cereals, beans, and tubers; Cereal includes rice, wheat, and corn.

FigureFigure 5.5.ChangesChanges in in grain grain and and cereal cereal self-s self-suufficiencyﬃciency ratio from 2000 to 2015.

Traditionally, itit is is stressed stressed that that the the grain grain self-su self-sufficiencyfficiency ratio ratio should should be more be thanmore 0.95 than to 0.95 ensure to foodensure security food insecurity China. However,in China. atHowever, present, it at is costlypresent, to maintainit is costly such ato high maintain self-su ffisuchciency a ratio.high Theself-sufficiency overuse of groundwaterratio. The overus resultse of in groundwater land subsidence results and in the land overuse subsidence of pesticide, and the fertilizer, overuse and of plasticpesticide, film fertilizer, results in and arable plastic land film pollution, results in which arable increase land pollution, the pressure which on increase domestic the resources pressure and on environment.domestic resources Because and of environment. global economic Because integration, of glob weal caneconomic make fullintegration, use of the we international can make full market use toof importthe international an appropriate market amount to import of grain. an appropriat There is noe amount doubt that of grain. this approach There is isno a feasibledoubt that way this to guaranteeapproach is a sua feasiblefficient supplyway to andguarantee reduce a the sufficient pressure supply on resources and reduce such the as arablepressure land on and resources water. However,such as arable it is clearland thatand thewater. international However, marketit is clear is that affected the international by price, politics, market energy, is affected finance, by and price, so on.politics, The increaseenergy, offinance, grain importsand so meanson. The that increase the impacts of grain of the imports international means marketthat the will impacts also increase, of the whichinternational will threaten market food will security. also increase, Thus, it needswhich towill be stressedthreaten that food we security. must not Thus, be too it dependent needs to onbe thestressed international that we market.must not From be too this dependent perspective, on ourthe strategicinternational option market. to ensure From food this security perspective, should our be tostrategic adjust theoption grain to self-su ensurefficiency food ratiosecurity by increasing should be domestic to adjust production the grain and self-sufficiency importing appropriately. ratio by Weincreasing should bedomestic entirely production self-sufficient and with importing regard toappropriately. grain for subsistence, We should which be isentirely actually self-sufficient a very basic need.with regard A moderate to grain increase for subsistence, in the imports which of is grain actually for feeda very and basic industry need. A should moderate be allowed. increase This in the is alsoimports recognized of grainby for many feed and scholars industry that Chinashould should be allowed. adjust This the foodis also security recognized strategy by many in the scholars current situationthat China [36 should–38]. adjust the food security strategy in the current situation [36–38]. Hence, inin this this study, study, the the grain grain self-su self-sufficienfficiency ratiocy isratio forecasted is forecasted based onbased the di onfferent the purposesdifferent ofpurposes grain consumption of grain consumption and their respective and their self-su respectivefficiency self-sufficiency ratios. Generally, ratios. the Generally, grain is for the food, grain feed, is industry,for food, andfeed, seed. industry, Because and the seed. grain Because for seed the is little, grain it isfo notr seed taken is little, into account. it is not The taken detailed into account. formula isThe as detailed follows: formula is as follows: A = Rr Ar + Rf Af + Ri Ai (2) A=R××A +R ××A +R ××A (2) where A is the grain self-sufficiency ratio; Rr, Rf, Ri are respectively the ratio of grain for food, feed, where A is the grain self-sufficiency ratio;R,R,R are respectively the ratio of grain for food, feed, and industry; Ar,Af,Ai are the self-sufficiency ratio of grain for food, feed and industry. A A A and industry;At present, , the, proportionare the self-sufficiency of grain for food,ratio of feed, grain and for industryfood, feed in and China industry. is about 4:2:1 [39]. AccordingAt present, to the the changes proportion in per capitaof grain consumption for food, feed, of major and industry foods (Figure in China4), the is grainabout for 4:2:1 food [39]. is decliningAccording and to the the changes grain for in feed per iscapita increasing. consumption The change of major will foods continue (Figure in the4), the near grain future for and food the is proportiondeclining and of grain the grain for food, for feed andis increasing. industry in The China change is predicted will continue to be 45%:35%:20% in the near future [11,40 ].and Based the onproportion the above of consideration, grain for food, three feed possible and industry scenarios in are China set up: is predicted The grain self-suto be 45%:35%:20%fficiency ratio is[11,40]. on (1) aBased high levelon the (0.95), above (2) consideration, a middle level three (0.90), possible and (3) ascenarios low level are (0.85). set up: In the The first grain scenario, self-sufficiency the grain self-suratio isffi onciency (1) a ratio high is level 0.95. (0.95), We are (2) fully a middle self-su ffilevelcient (0.90), for food, and highly(3) a low self-su levelffi cient(0.85). for In feed, the andfirst basicallyscenario, self-suthe grainfficient self-sufficiency for industry. Inratio this is scenario, 0.95. We the are negative fully impactself-sufficient of international for food, trade highly on ourself-sufficient grain supply for willfeed, decrease, and basically but there self-sufficient will probably for industry. be more In pressure this scenario, on domestic the negative resources impact and environment.of international In thetrade second on our scenario, grain supply the grain will self-su decrease,fficiency but ratio there is 0.90.will probably We are highly be more self-su pressurefficient on domestic resources and environment. In the second scenario, the grain self-sufficiency ratio is 0.90. We are highly self-sufficient for food and basically self-sufficient for feed. Since the Sustainability 2019, 11, 4769 8 of 15 Sustainability 2019, 11, 4769 8 of 15 forself-sufficiency food and basically of grain self-su for ffiindustrycient for is feed. 0.80, Since the thegrain self-su for ffiindustryciency of partly grain relies for industry on international is 0.80, the graintrade.for In industrythis scenario, partly there relies is on a international basic food security trade. In and this scenario,the pressure there on is aarable basic foodland, security water, and theother pressure resources on arableis slightly land, decreased. water, and In other the third resources scenario, is slightly the grain decreased. self-sufficiency In the third ratio scenario, is 0.85. We the grainare still self-su basicallyfficiency self-sufficient ratio is 0.85. Wefor arefood. still Since basically the self-suself-sufficiencyfficient for food.ratios Sinceof grain the self-sufor feedfficiency and ratiosindustry of grainare both for feed0.80, and we industrywill face arerisks both because 0.80, we of willinternational face risks market because uncertainties. of international However, market uncertainties.this scenario However,will effectively this scenario reduce will pressure effectively on reduce agricultural pressure resources on agricultural and resourcesimprove andthe improveenvironment. the environment.

2.2.4. Grain Yield per Unit Area Grain yieldyield perper unit unit area area represents represents the the arable arable land land productivity, productivity, which which is influenced is influenced by natural by environments,natural environments, agricultural agricultural resource resource efficiency, efficiency, science and science technology, and technology, policies, markets, policies, and markets, so on. Overand so the on. past Over several the past years, several grain years, yield pergrain unit yield area per has unit shown area anhas increasing shown an trend increasing with fluctuations trend with (Figurefluctuations(Figure6). The grain 6). yield The per grain unit yield area per increased unit area by 28.7%increased from by 4261 28.7% kg /fromha in 4261 2000 kg/ha to 5483 in kg 2000/ha into 2015,5483 kg/ha as some in 2015, limitations as some of agriculturallimitations of production agricultural have production been overcome have been recently. overcome recently.

kg/ha 6000 9.00%

6.00% 4000

3.00%

2000 0.00%

0 -3.00% Year 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Grain yield per unit area Growth rate

Figure 6.6.ChangesChanges in in grain grain yield yield per per unit unit area area and and its its growth growth rate from 2000 to 2015.

Grain yield per unit area is aaffectedffected by both natural and anthropic factors such as climate, soil, plant diseases, insect pests, irrigation, fertilization, and so on. Among them, the impacts of climate changes onon grain grain productivity productivity cannot cannot be ignored.be ignored. Because Because of regional of regional differences differences in China, in theChina, impacts the areimpacts obviously are obviously different. different. The negative The impacts negative are impacts greater are than greater the positive than inthe the positive south ofin China,the south which of isChina, opposite which in theis opposite north [41 ].in Moreover,the north the[41]. advances Moreover, in agricultural the advances science in agricultural and technology science greatly and promotetechnology the greatly grain productivity. promote the The grain uncertainty productivity of these. The factors uncertainty makes it diofffi thesecult to factors predict makes the grain it yielddifficult in theto predict future. the In grain this study, yield in it isthe assumed future. In that this the study, negative it is assumed impacts ofthat climate the negative change impacts can be reducedof climate by change the advances can be of reduced agricultural by the science advances and technology of agricultural in the future.science Theand graintechnology yield per in unitthe areafuture. is stillThe potential grain yield but limited. per unit According area is tostill the potential law of diminishing but limited. marginal According returns to of the production law of factors,diminishing the marginalmarginal productreturns firstof production increases andfactor thens, the decreases marginal with product the increase first increases of factor and inputs. then Similarly,decreases whenwith the grain increase yield perof factor unit areainputs. is increasing Similarly, and when closed grain to yield its potential, per unit thearea growth is increasing rate of grainand closed yield perto unitits potential, area will graduallythe growth decrease rate of [42 grain,43]. Theyield changes per unit in thearea grain will yieldgradually per unit decrease area in China[42,43]. are The consonant changes within the this grain rule. yield Refer per to unit the relevantarea in China research are [ 44consonant] and establish with this the rule. decay Refer model: to the relevant research [44] and establish the decay model: Yt = ln Uq Ut = it + j (3) − − 𝑌 =𝑙𝑛𝑈 −𝑈=−𝑖𝑡+𝑗 (3) it+j Ut = Uq e− (4) 𝑈 =𝑈 −𝑒− (4) where 𝑈 is the potential grain yield per unit area; 𝑈 is the grain yield per unit area in the year t; 𝑈 −𝑈is the promotion potential grain yield per unit area; i and j are both the model parameters; t is the year (the starting year is 1). Sustainability 2019, 11, 4769 9 of 15

where Uq is the potential grain yield per unit area; Ut is the grain yield per unit area in the year t; Sustainability 2019, 11, 4769 9 of 15 Uq Ut is the promotion potential grain yield per unit area; i and j are both the model parameters; t is − the yearAccording (the starting to the yeargrain is yield 1). per unit area of the high-yielding demonstration areas in China, it can increaseAccording to 9100 to the kg/ha, grain which yield peris also unit the area mo ofdel-estimated the high-yielding average demonstration yield potential areas in indifferent China, it can increase to 9100 kg/ha, which is also the model-estimated average yield potential in different countries and regions [45,46]. Hence, in this study,𝑈 is set at 9100 kg/ha. The sample data is the graincountries yield and per regions unit area [45 from,46]. Hence,2000 to in 2015. this The study, resultsUq is are set atas 9100follows: kg/ha. The sample data is the grain yield per unit area from 2000 to 2015. The results are as follows: ( ) 2 𝑌 =𝑙𝑛 9100 − 𝑈 = −0.0203𝑡 + 8.5241(R=0.9732)2 Yt = ln(9100 Ut) = 0.0203t + 8.5241 R = 0.9732 − − .. 𝑈 = 9100 − 𝑒 0.0203t+8.5241 Ut = 9100 e− Then, it is predicted that the grain yield per− unit area in 2030 and 2040 are 6417 kg/ha and 6910 kg/ha,Then, respectively. it is predicted that the grain yield per unit area in 2030 and 2040 are 6417 kg/ha and 6910 kg/ha, respectively. 2.2.5. Multiple Cropping Index 2.2.5. Multiple Cropping Index The multiple cropping index, the ratio of crop sown area to arable land area, reflects the developmentThe multiple of crop cropping production index, and the arable ratio land of crop use sownefficiency. area In to recent arable years, land area,the comparative reflects the advantagedevelopment of agriculture of crop production has been andlow arableso that land the enthusiasm use efficiency. of farmers In recent to years,grow grain the comparative is affected. Atadvantage the same of time, agriculture some hasregions been lowhave so tried that therotational enthusiasm and offallow farmers farming to grow to grainimprove is aff soilected. fertility, At the whichsame time, results some in regionsthe decline have triedof the rotational multiple and cropping fallow farmingindex, especially to improve in soil plains. fertility, Nationally, which results the multiplein the decline cropping of the index multiple increased cropping from index, 2000 to especially 2008 and in from plains. 2009 Nationally, to 2015, mostly the multiple between cropping 1.2 and 1.3(Figureindex increased 7). The from change 2000 tois 2008due andto the from differen 2009 toce 2015, between mostly the between first and 1.2 second and 1.3 National (Figure7 ).Land The Resourcechange is Survey due to theof China. difference between the first and second National Land Resource Survey of China.

1.3

1.2

1.1

1 Year 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Multiple cropping index

Figure 7. ChangesChanges in in the the multiple multiple cro croppingpping index index from from 2000 2000 to to 2015. 2015.

WithWith the population increasing and arable land decreasing, developing multiple cropping cropping to to improveimprove the the index index is is an an important important way way to to increase increase grain grain production production and and ensure ensure food food security security in in China.China. In In the the future, future, we we should should focus focus on on overcoming overcoming the the key key obstacles obstacles to to improving improving the the quality of low-andlow-and medium-grademedium-grade arable arable land land by landby land consolidation, consolidation, the construction the construction of high-standard of high-standard farmland, farmland,and the improvement and the improvement of irrigation of systems;irrigation therefore, systems; thetherefore, multiple the cropping multiple index cropping will increaseindex will to increasea certain to extent. a certain Yet whatextent. is theYet potentialwhat is the multiple potential cropping multiple index cropping in China? index Many in China? scholars Many have scholarsresearched have it and researched the results it and are mostlythe results between are mostly 1.75 and between 2.0 [47– 1.7549]. However,and 2.0 [47–49]. the above However, results the are abovetheoretical results values are theoretical and cannot values be achieved and cannot actually, be becauseachieved some actually, of the because arable landsome is of uncultivated. the arable landWhen is considering uncultivated. the When pressure considering on resources the and pressu the environment,re on resources we and should the developenvironment, a resource-saving we should developand environment-friendly a resource-saving multipleand environment-friendly cropping system. Bymultiple analyzing cropping the changes system. in By recent analyzing years andthe changesconsidering in recent future policyyears guidance,and considering we predict future that, policy in the future,guidance, China’s we multiplepredict that, cropping in the index future, will China’srise gradually multiple to acropping higher historical index will level, rise reachinggradually 1.3. to a higher historical level, reaching 1.3.

2.2.6. Ratio of Grain to Crop Sown Area Sustainability 2019, 11, 4769 10 of 15

2.2.6.Sustainability Ratio of 2019 Grain, 11, 4769 to Crop Sown Area 10 of 15 The ratio of grain to crop sown area directly reflects the production structure of China’s crop The ratio of grain to crop sown area directly reflects the production structure of China’s crop farming, which is influenced by many factors such as labor productivity, agriculture policy guidance, farming, which is influenced by many factors such as labor productivity, agriculture policy and the fluctuation of the agricultural products market (such as demand and price). The changes in guidance, and the fluctuation of the agricultural products market(such as demand and price). The thechanges ratio of in grain the ratio to crop of grain sown to area crop from sown 2000 area to from 2015 2000 are shownto 2015 inare Figure shown8 .in From Figure 2000 8. From to 2003, 2000 the ratioto declined2003, the fromratio 0.69declined to 0.65. from However, 0.69 to 0.65. it then Howeve graduallyr, it then rose fromgradually 0.65 inrose 2003 from to 0.690.65 inin 2006.Since2003 to then,0.69 the in 2006.Since ratio has been then, hovering the ratio athas approximately been hovering 0.68at approximately with little change. 0.68 with little change.

0.71

0.69

0.67

0.65 Year 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Ratio of grain to crop sown area

FigureFigure 8. 8.ChangesChanges inin thethe ratio of grain to to crop crop sown sown area area from from 2000 2000 toto 2015. 2015.

StabilizingStabilizing the the cultivated cultivated graingrain areaarea andand proportion is is also also an an important important way way to toensure ensure food food security.security. China’s China’s“No.1 “No.1 Central Central Document” Document” inin 20122012 clearlyclearly statedstated thatthat everyevery eeffortﬀort shouldshould bebe mademade to stabilizeto stabilize the grain the grain sown sown area, area, expand expand the productionthe production of scarce of scarce varieties, varieties, and and focus focus on improvingon improving yield andyield quality. and Underquality. the Under guidance the guid of relevantance of relevant departments, departments, the grain the production grain production ratio has ratio gradually has stabilizedgradually with stabilized the adjustment with the adjustment and optimization and optimiza of thetion agricultural of the agricultural structure. structure. Though Though the income the fromincome planting from cash planting crops cash is higher crops thanis higher that than from that planting from grain,planting the grain, subsidy the policysubsidy will policy be improvedwill be graduallyimproved in gradually the future in tothe motivate future tofarmers motivate to farm growers grain.to grow Thus, grain. the Thus, proportion the proportion of grain of grain will be will be relatively stable in the future. Correspondingly, in this study, the ratio of grain to crop sown relatively stable in the future. Correspondingly, in this study, the ratio of grain to crop sown area will area will remain relatively stable at approximately 0.68. remain relatively stable at approximately 0.68. 3. Results and Discussions 3. Results and Discussions

3.1.3.1. Arable Arable Land Land Demand Demand in in Di Differentﬀerent Scenarios Scenarios Based on the predictions of the above six factors, arable land demand in nine different scenarios Based on the predictions of the above six factors, arable land demand in nine diﬀerent scenarios calculated according to Formula 1 is shown in Table 1. calculated according to Formula 1 is shown in Table1.

Table 1.Arable land demand in different scenarios. Unit: million ha. Table 1. Arable land demand in diﬀerent scenarios. Unit: million ha. Per Capita Grain Demand Grain Self-Sufficiency Ratio 2030 2040 Per Capita Grain Demand Grain Self-Suﬃciency Ratio 2030 2040 High 103.00 94.65 Subsistence HighMiddle 103.0097.57 89.67 94.65 Subsistence MiddleLow 97.5792.15 84.68 89.67 Low 92.15 84.68 High 122.61 112.68 Moderately prosperous HighMiddle 122.61116.16 106.75 112.68 Moderately prosperous Middle 116.16 106.75 Low 109.71 100.82 Low 109.71 100.82 High 134.88 123.94 High 134.88 123.94 Prosperous Middle 127.78 117.42 Prosperous Middle 127.78 117.42 LowLow 120.68120.68 110.90 110.90 Sustainability 2019, 11, 4769 11 of 15

Since the population will reach its peak in 2030 and the grain yield per unit area will be lower than that in 2040, the pressure to maintain sufficient arable land in 2030will be greater. With the continuous development of the social economy and the growth in people’s living standards, the prediction of arable land demand, considering only subsistence, is too low. If we take it as the “red line” (the minimum requirement) for food security that we must protect, the number could be too optimistic to protect sufficient amounts of arable land. This approach also may lead to rapid loss of arable land, which will threaten the food security of our country. As per capita grain demand on the prosperous level is 10% higher than that on the moderately prosperous level, the arable land demand under the circumstances is obviously so high that we will be under enormous pressure to protect resources and the environment. Nevertheless, on a moderately prosperous level, which is also regarded as the demand for a nutritious diet, if we maintain the current self-sufficiency ratio, the arable land demand is 109.71 million ha in 2030 and 100.82 million ha in 2040. If the grain self-sufficiency ratio increases to 0.9, the arable land demand is 116.16 million ha in 2030 and 106.75 million ha in 2040. In these two situations, having a nutritious and healthy diet and making full use of international resources and markets are both taken into account. The outcomes are more referential. According to the Chinese government, China needs to pledge to protect a minimum of 120 million ha of arable land as the “red line” for food security, which is a slightly higher than the results in this study. The main reason lies in that the current arable land productivity retains potential, the quality of some arable land is of low-and medium-grade and 0.01% of arable land is destroyed by disasters annually. Thus, at present, the “red line” is still pledged to protect.

3.2. Challenges of Food Security and Protection of Arable Land Food security in China attracts many scholars from all over the world due to the challenges of a huge population and limited arable land. At present, overuse of surface water, declining groundwater levels, and water pollution are threatening the sustainability of China’s agricultural production [50]. The overexploitation of groundwater results in land subsidence. Water, arable land, and air pollution threaten the grain productivity and quality. The food market is facing the pressures of domestic and international market competition. At present, in China, the strategic planning of grain import and export trade is still not clear enough and the adaptability to changes in the international market is deﬁcient. At the same time, because of the structural contradiction between domestic supply and demand, some crops are highly dependent on the import [51]. From the foregoing, in the near future, the national population will continue to increase and the population structure and the dietary pattern will gradually change, which will lead to increasing food demand. With the income increasing, the residents pursue a better life, which means they will focus on both food quantity and quality. It can be argued that food security in China is facing all kinds of challenges. Arable land, as a strategic resource of human existence and development, is basis of food security. Recently, with the rapid development of industrialization and urbanization, a large number of arable land was occupied and contaminated. There are serious concerns about the quality of arable land—whether its ability can supply future generations with enough food. As reserve arable land in China is limited, protection of arable land is central to food security in China in the future.

3.3. ApproachesTowards Food Security and Protection of Arable Land To ensure food security in China, the basic principle is to rely on the domestic production chiefly and import appropriately. The key is to call for a sound food demand, import in an appropriate proportion, and improve the productivity. In recent years, the real per capita grain consumption in China is greater than per capita grain demand in the balance dietary pattern [52], which increases the pressure on protection of arable land. Hence, the residents should be guided to cultivate sound food consumption habits with the goal of nutrition and health in order to control per capita grain demand. At the same time, food security strategy should be adjusted appropriately. The international market and resources should be made full use of to relieve the pressure on domestic resources and Sustainability 2019, 11, 4769 12 of 15 environment. China’s “No.1 Central Document” in 2019 stated that China should proactively increase the imports of the agricultural products in short supply. The guidelines should be drawn up that how much should be imported, what are the sustainable channels and how to respond to the negative effect on domestic agricultural production. Thus, the strategic planning of grain import and export trade should be made to enhance the adaptability to changes in the international market. In addition, the agricultural productivity in China should be improve constantly by the improvement of agricultural production technology and the protection of arable land. “Trinity comprehensive protection of quantity, quality and ecology of arable land” is advocated in China. It involves a series of activities to maintain and improve the production, ecological, and life functions of arable land [53]. At the same time, the mission to protect arable land is clear—we should maintain the quantity, improve the quality, and protect arable land ecosystems. The key to maintaining quantity is to protect arable land, particularly high standard basic farmland, against being occupied by urban expansion and to increase arable land by rural land consolidation. What is central to the quality is to improve that of low-and medium-grade arable land, which China will increasingly rely on to feed itself [54]. According to the national plan for land consolidation (2016–2020), from 2011 to 2015, land consolidation raised one grade of the quality of 35.3 million ha low-and medium-grade arable land, whose grain productivity rose by 37 million tons. If the low-and medium-grade arable land, 70% of arable land, could be consolidated, the grain productivity could increase by about 100 million tons accordingly. This shows the potential is still great. It is also effective to fertilize, rotate, and leave fallow the arable land rationally. In addition to improving the quality of arable land itself, water and air pollution should be controlled to reduce the negative impacts on the arable land quality and grain productivity. Further, arable land quality dynamic monitoring system should be established. In order to protect the stability and health of the arable land ecosystem, conservation tillage should be more used. Ecological compensation for arable land should be refined to enhance the enthusiasm of farmers to protect the arable land.

4. Conclusions In this paper, the changes in national population, residents’ food consumption, grain yield per unit area, self-sufficiency ratio, multiple cropping index, and ratio of grain to crop sown area from 2000 to 2015 were analyzed. In addition, we predicted the future. On this basis, we forecasted the arable land demand in nine possible situations. The results show that the population will reach its peak in 2030 and will be smaller in 2040.The yield per unit area will gradually increase with the development of agriculture science and technology. Therefore, the arable land demand in 2030 will be greater than that in 2040. After 2030, the pressure may be reduced due to the declining population and increasing production capacity. It is also effective to reduce the pressure to guide residents to have a nutritious and healthy diet and make full use of international resources and markets. Judging from the current situation of China’s economic and social development, in the near future, the total population will continue to increase, and the population structure and the dietary pattern will gradually change, which will lead to increasing food demand and effect food security. There are serious concerns about decreasing quantity and worrying quality of arable land. Therefore, food security and arable land protection in China will still face many challenges in the future. However, the Chinese should hold the rice bowl firmly in our own hands. It needs to be emphasized that maintaining sufficient arable land is still crucial to ensuring food security. The “red line”, 120 million ha of arable land should be firmly defended. By simultaneously protecting the quantity, quality, and ecology of arable land we can better protect Chinese arable land and ensure food security.

Author Contributions: A.C. collected the data, analyzed the data and wrote the manuscript. H.H. helped collect the data and advised and helped in the process of paper writing. J.W. helped carry out the calculations. M.L. and Q.G. provided suggestions. J.H. provided valuable suggestions and support. Sustainability 2019, 11, 4769 13 of 15

Funding: This work was supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (No. 2015BAD06B01) and the National Nature Science Foundation for Distinguished Young Scholars of China (No. 51709274). Conﬂicts of Interest: The authors declare no conﬂict of interest.

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