农业机械化水平对湖北农户耕地复种指数的影响
|
摘要
耕地复种指数的提升对我国粮食安全战略实施和三农问题解决意义重大。为了考察农业机械化水平对湖北农户耕地复种指数的影响,以1 682份湖北农户调查数据为基础,通过运用IVTobit和IVProbit回归模型,探讨农业机械化水平对农户耕地复种指数的影响及其在不同类型农作物耕地间的差异性。研究结果表明:1)农业机械化水平每提升1%,耕地复种指数提高1.393%,粮食作物耕地复种指数提高0.988%,经济作物耕地复种指数提高2.160%。2)从不同类型农作物耕地复种意愿来看,农业机械化水平每提升1%,农户对粮食作物耕地复种意愿的概率提高3.100%,对经济作物耕地复种意愿的概率提高5.361%。从其他控制变量来看,户主教育、户主年龄、家庭非农收入占比、家庭转出土地、气温变化对农户耕地复种指数存在显著的负向影响;家庭规模、农作物品种数量、地区类型对农户耕地复种指数存在显著的正向影响。总之,农户农业机械化水平的提升对耕地复种有积极作用,特别对经济作物耕地复种指数的提升作用尤为明显。
Increased multi-cropping index in cultivated lands is critical for food security strategies and issues concerning in agriculture, countryside and peasant communities in China. Presently, many studies exist on multiple cropping index. However, most of these studies are based on national statistics, with fewer studies on peasant household conditions. Multiple cropping of cultivated lands is the production activities of individual rural households. Therefore, the use of macro-statistical data had failed to adequately capture inherent heterogeneities in peasant conditions in different regions. Furthermore, it has limited research analysis to only the factors that affect multiple cropping index at macro scale. This has made it difficult to accurately analyze the driving factors at micro scale. Here, we used survey data from 1 682 peasant households in Hubei Province to investigate the impact of the level of agricultural mechanization on multiple cropping index at microscopic scale. To further avoid the possibility of endogeneity and sample selection bias in the model, we used IVTobit and IVProbit regression models to explore the impact of the level of agricultural mechanization on multiple-cropping index and the differences in various types of crops. The results showed that: 1) ordinary least square(OLS)-estimation result without consideration for sample selection bias and endogeneity and processed result were quite different.This indicated that the original OLS regression model significantly underestimated the effect of the level of agricultural mechanization on peasant household conditions. Regression coefficients pointed out that the level of agricultural mechanization had significant positive impact on multiple cropping index. For every 1% increase in the level of agricultural mechanization, multiple cropping index increased by 1.393%. This confirmed the hypothesis that agricultural mechanization effectively reduced the time of agricultural production, ensured seasonality of multiple crops, maximized utilization of land and increased the degree of cultivation. In addition,education and age of household head, proportion of non-agricultural income, transferred land and temperature change had dramatic negative effect on multiple cropping index of cultivated lands. Family size, number of crop varieties and type of area had significant positive effect on peasant household conditions. 2) Based on the analysis of the action mechanism of multiple cropping index of cultivated lands, there was significant difference in the impact of the level of agricultural mechanization on multiple cropping index and willingness of different types of crops. The level of agricultural mechanization affected cropping index of cash crops more than grain crops. Compared with peasants who grew food crops, those who grew cash crops were more willing to plant more with increasing level of agricultural mechanization. This was mainly because economic effects of cash crops were higher and peasants were more likely to multiply cash crops them than grain crops. The latter not only had strong seasonality, but also was not plantable in off-season periods, while the former had short growth cycle with operable production process. In summary, we argued that improvement of the level of agricultural mechanization by peasants played an active role in multiple cropping index in cultivated lands, especially for increasing cropping index of cash crops. In order to further improve the degree of cultivating land and to ensure domestic food security in peasant communities, government should vigorously promote the use of agricultural mechanization, strengthen policy support for peasants who cultivate grains in plains and reform grain storage systems.
Increased multi-cropping index in cultivated lands is critical for food security strategies and issues concerning in agriculture, countryside and peasant communities in China. Presently, many studies exist on multiple cropping index. However, most of these studies are based on national statistics, with fewer studies on peasant household conditions. Multiple cropping of cultivated lands is the production activities of individual rural households. Therefore, the use of macro-statistical data had failed to adequately capture inherent heterogeneities in peasant conditions in different regions. Furthermore, it has limited research analysis to only the factors that affect multiple cropping index at macro scale. This has made it difficult to accurately analyze the driving factors at micro scale. Here, we used survey data from 1 682 peasant households in Hubei Province to investigate the impact of the level of agricultural mechanization on multiple cropping index at microscopic scale. To further avoid the possibility of endogeneity and sample selection bias in the model, we used IVTobit and IVProbit regression models to explore the impact of the level of agricultural mechanization on multiple-cropping index and the differences in various types of crops. The results showed that: 1) ordinary least square(OLS)-estimation result without consideration for sample selection bias and endogeneity and processed result were quite different.This indicated that the original OLS regression model significantly underestimated the effect of the level of agricultural mechanization on peasant household conditions. Regression coefficients pointed out that the level of agricultural mechanization had significant positive impact on multiple cropping index. For every 1% increase in the level of agricultural mechanization, multiple cropping index increased by 1.393%. This confirmed the hypothesis that agricultural mechanization effectively reduced the time of agricultural production, ensured seasonality of multiple crops, maximized utilization of land and increased the degree of cultivation. In addition,education and age of household head, proportion of non-agricultural income, transferred land and temperature change had dramatic negative effect on multiple cropping index of cultivated lands. Family size, number of crop varieties and type of area had significant positive effect on peasant household conditions. 2) Based on the analysis of the action mechanism of multiple cropping index of cultivated lands, there was significant difference in the impact of the level of agricultural mechanization on multiple cropping index and willingness of different types of crops. The level of agricultural mechanization affected cropping index of cash crops more than grain crops. Compared with peasants who grew food crops, those who grew cash crops were more willing to plant more with increasing level of agricultural mechanization. This was mainly because economic effects of cash crops were higher and peasants were more likely to multiply cash crops them than grain crops. The latter not only had strong seasonality, but also was not plantable in off-season periods, while the former had short growth cycle with operable production process. In summary, we argued that improvement of the level of agricultural mechanization by peasants played an active role in multiple cropping index in cultivated lands, especially for increasing cropping index of cash crops. In order to further improve the degree of cultivating land and to ensure domestic food security in peasant communities, government should vigorously promote the use of agricultural mechanization, strengthen policy support for peasants who cultivate grains in plains and reform grain storage systems.
引文
[1]吴大放,刘艳艳,董玉祥,等.我国耕地数量、质量与空间变化研究综述[J].热带地理,2010,30(2):108-113WU D F,LIU Y Y,DONG Y X,et al.Review on the research of quantity,quality and spatial change of cultivated land in China[J].Tropical Geography,2010,30(2):108-113
[2]DENG X Z,HUANG J K,ROZELLE S,et al.Impact of urbanization on cultivated land changes in China[J].Land Use Policy,2015,45:1-7
[3]刘保花,陈新平,崔振岭,等.三大粮食作物产量潜力与产量差研究进展[J].中国生态农业学报,2015,23(5):525-534LIU B H,CHEN X P,CUI Z L,et al.Research advance in yield potential and yield gap of three major cereal crops[J].Chinese Journal of Eco-Agriculture,2015,23(5):525-534
[4]KRAVCHENKO A N,SNAPP S S,ROBERTSON G P.Field-scale experiments reveal persistent yield gaps in low-input and organic cropping systems[J].Proceedings of the National Academy of Sciences of the United States of America,2017,114(5):926-931
[5]李琳凤,李孟刚.提高复种指数是保障我国粮食安全的有效途径[J].管理现代化,2012,(3):26-28LI L F,LI M G.Improving the multiple cropping index is an effective way to ensure food security in China[J].Modernization of Management,2012,(3):26-28
[6]何文斯,吴文斌,余强毅,等.1980~2010年中国耕地复种可提升潜力空间格局变化[J].中国农业资源与区划,2016,37(11):7-14HE W S,WU W B,YU Q Y,et al.Changes in spatio-temporal distribution of potential increment multiple cropping in China during 1980~2010[J].Chinese Journal of Agricultural Resources and Regional Planning,2016,37(11):7-14
[7]WU W B,YU Q Y,VERBURG P H,et al.How could agricultural land systems contribute to raise food production under global change?[J].Journal of Integrative Agriculture,2014,13(7):1432-1442
[8]唐华俊,吴文斌,余强毅,等.农业土地系统研究及其关键科学问题[J].中国农业科学,2015,48(5):900-910TANG H J,WU W B,YU Q Y,et al.Key research priorities for agricultural land system studies[J].Scientia Agricultura Sinica,2015,48(5):900-910
[9]GRASSINI P,ESKRIDGE K M,CASSMAN K G.Distinguishing between yield advances and yield plateaus in historical crop production trends[J].Nature Communications,2013,4:2918
[10]PUGH T A M,MüLLER C,ELLIOTT J,et al.Climate analogues suggest limited potential for intensification of production on current croplands under climate change[J].Nature Communications,2016,7:12608
[11]吴文斌,唐华俊,杨鹏,等.基于空间模型的全球粮食安全评价[J].地理学报,2010,65(8):907-918WU W B,TANG H J,YANG P,et al.Model-based assessment of food security at a global scale[J].Acta Geographica Sinica,2010,65(8):907-918
[12]吴文斌,余强毅,陆苗,等.耕地复种指数研究的关键科学问题[J].中国农业科学,2018,51(9):1681-1694WU W B,YU Q Y,LU M,et al.Key research priorities for multiple cropping systems[J].Scientia Agricultura Sinica,2018,51(9):1681-1694
[13]卞新民,冯金侠.多元多熟种植制度复种指数计算方法探讨[J].南京农业大学学报,1999,22(1):11-15BIAN X M,FENG J X.Method of calculating cropping system index of diversified multiple cropping system[J].Journal of Nanjing Agricultural University,1999,22(1):11-15
[14]左丽君,张増祥,董婷婷,等.耕地复种指数研究的国内外进展[J].自然资源学报,2009,24(3):553-560ZUO L J,ZHANG Z X,DONG T T,et al.Progress in the research on the multiple cropping index[J].Journal of Natural Resources,2009,24(3):553-560
[15]Devendra C,Thomas D.Smallholder farming systems in Asia[J].Agricultural Systems,2002,71(1/2):17-25
[16]中华人民共和国农业部粮食作物生产局.改变耕作制度、扩大复种面积[M].北京:农业出版社,1958Department of Food Crop Production,Ministry of Agriculture of the People’s Republic of China.Changing Farming System and Expanding Multiple Cropping Area[M].Beijing:Agricultural Press,1958
[17]康清林,李春蕾,张玉虎.2001-2010年江苏省复种指数变化及其影响因子分析[J].首都师范大学学报:自然科学版,2017,38(5):86-94KANG Q L,LI C L,ZHANG Y H.The cropping index change and impact factor analysis in Jiangsu Province between 2001 and 2010[J].Journal of Capital Normal University:Natural Science Edition,2017,38(5):86-94
[18]李阔,许吟隆.适应气候变化的中国农业种植结构调整研究[J].中国农业科技导报,2017,19(1):8-17LI K,XU Y L.Study on adjustment of agricultural planting structures in China for adapting to climate change[J].Journal of Agricultural Science and Technology,2017,19(1):8-17
[19]刘巽浩.耕作学[M].北京:中国农业出版社,1994LIU X H.Farming Science[M].Beijing:China Agriculture Press,1994
[20]李晶,任志远.基于SPOTNDVI的陕西省耕地复种指数时空变化[J].干旱区资源与环境,2011,25(10):86-91LI J,REN Z Y.The monitoring for cropping index of arable land in northwest region using SPOTNDVI-A case of Shaanxi Province[J].Journal of Arid Land Resources and Environment,2011,25(10):86-91
[21]田罗,周文佐,何万华,等.2000-2016年四川省耕地种植指数时空变化及其自然潜力分析[J].中国生态农业学报,2018,26(8):1206-1216TIAN L,ZHOU W Z,HE W H,et al.Spatio-temporal evolution and potential analysis of cropping index in Sichuan Province during 2000-2016[J].Chinese Journal of Eco-Agriculture,2018,26(8):1206-1216
[22]徐国鑫,金晓斌,宋佳楠,等.耕地集约利用对粮食产量变化影响的定量分析--以江苏省为例[J].地理研究,2012,31(9):1621-1630XU G X,JIN X B,SONG J N,et al.The impact of intensive use of agricultural land on grain yields:A case study of Jiangsu Province[J].Geographical Research,2012,31(9):1621-1630
[23]张倩,许泉,王全忠,等.补贴政策与农户稻作制度选择--基于湖南省微观调研的证据[J].产业经济研究,2016,(6):89-99ZHANG Q,XU Q,WANG Q Z,et al.The effect of subsidy policy on rice planting pattern choices of peasant households:Evidence from micro-investigation in Hunan Province[J].Industrial Economics Research,2016,(6):89-99
[24]闫慧敏,刘纪远,曹明奎.近20年中国耕地复种指数的时空变化[J].地理学报,2005,60(4):559-566YAN H M,LIU J Y,CAO M K.Remotely sensed multiple cropping index variations in China during 1981-2000[J].Acta Geographica Sinica,2005,60(4):559-566
[25]张乐勤,陈素平,陈发奎.基于边际模型的中国城镇化演进对耕地影响极限研究[J].中国生态农业学报,2014,22(7):837-842ZHANG L Q,CHEN S P,CHEN F K.A marginal model-based study of the ultimate influence of China’s urbanization evolution on cropland[J].Chinese Journal of Eco-Agriculture,2014,22(7):837-842
[26]梁守真,马万栋,施平,等.基于MODIS NDVI数据的复种指数监测--以环渤海地区为例[J].中国生态农业学报,2012,20(12):1657-1663LIANG S Z,MA W D,SHI P,et al.Monitoring multiple cropping index using MODIS NDVI data:A case study of Bohai Rim[J].Chinese Journal of Eco-Agriculture,2012,20(12):1657-1663
[27]梁书民.我国各地区复种发展潜力与复种行为研究[J].农业经济问题,2007,28(5):85-90LIANG S M.Probing potentials of multiple cropping in the selected provinces in China[J].Issues in Agricultural Economy,2007,28(5):85-90
[28]曲福田,吴郁玲.土地市场发育与土地利用集约度的理论与实证研究--以江苏省开发区为例[J].自然资源学报,2007,22(3):445-454QU F T,WU Y L.Theoretical and empirical study on the land market and land use intensity:A case of the development zones in Jiangsu Province[J].Journal of Natural Resources,2007,22(3):445-454
[29]杨红梅,刘卫东,刘红光.土地市场发展对土地集约利用的影响[J].中国人口·资源与环境,2011,21(12):129-133YANG H M,LIU W D,LIU H G.Effects of land market development on land use intensity[J].China Population,Resources and Environment,2011,21(12):129-133
[30]崔宁波,张正岩.临储政策取消下玉米种植结构调整的影响因素与收入效应--基于黑龙江省镰刀弯地区调查数据的分析[J].商业研究,2017,59(11):153-163CUI N B,ZHANG Z Y.Influence factors and income effects of the adjustment of corn planting structure under the abolition of temporary storage policy:An analysis based on the survey data of sickle bend area in Heilongjiang Province[J].Commercial Research,2017,59(11):153-163
[31]STOCK J H,YOGO M.Testing for weak instruments in linear IV regression[M]//ANDREWS D W K,STOCK J H.Identification and Inference for Econometric Models Essays in Honor of Thomas Rothenberg.Cambridge:Cambridge University Press,2002
[32]彭继权,吴海涛,孟权.家庭生命周期、社会资本与农户生计策略研究[J].中国农业大学学报,2018,23(9):196-217PENG J Q,WU H T,MENG Q.Study on family life cycle,social capital and rural households’livelihood strategy[J].Journal of China Agricultural University,2018,23(9):196-217
[2]DENG X Z,HUANG J K,ROZELLE S,et al.Impact of urbanization on cultivated land changes in China[J].Land Use Policy,2015,45:1-7
[3]刘保花,陈新平,崔振岭,等.三大粮食作物产量潜力与产量差研究进展[J].中国生态农业学报,2015,23(5):525-534LIU B H,CHEN X P,CUI Z L,et al.Research advance in yield potential and yield gap of three major cereal crops[J].Chinese Journal of Eco-Agriculture,2015,23(5):525-534
[4]KRAVCHENKO A N,SNAPP S S,ROBERTSON G P.Field-scale experiments reveal persistent yield gaps in low-input and organic cropping systems[J].Proceedings of the National Academy of Sciences of the United States of America,2017,114(5):926-931
[5]李琳凤,李孟刚.提高复种指数是保障我国粮食安全的有效途径[J].管理现代化,2012,(3):26-28LI L F,LI M G.Improving the multiple cropping index is an effective way to ensure food security in China[J].Modernization of Management,2012,(3):26-28
[6]何文斯,吴文斌,余强毅,等.1980~2010年中国耕地复种可提升潜力空间格局变化[J].中国农业资源与区划,2016,37(11):7-14HE W S,WU W B,YU Q Y,et al.Changes in spatio-temporal distribution of potential increment multiple cropping in China during 1980~2010[J].Chinese Journal of Agricultural Resources and Regional Planning,2016,37(11):7-14
[7]WU W B,YU Q Y,VERBURG P H,et al.How could agricultural land systems contribute to raise food production under global change?[J].Journal of Integrative Agriculture,2014,13(7):1432-1442
[8]唐华俊,吴文斌,余强毅,等.农业土地系统研究及其关键科学问题[J].中国农业科学,2015,48(5):900-910TANG H J,WU W B,YU Q Y,et al.Key research priorities for agricultural land system studies[J].Scientia Agricultura Sinica,2015,48(5):900-910
[9]GRASSINI P,ESKRIDGE K M,CASSMAN K G.Distinguishing between yield advances and yield plateaus in historical crop production trends[J].Nature Communications,2013,4:2918
[10]PUGH T A M,MüLLER C,ELLIOTT J,et al.Climate analogues suggest limited potential for intensification of production on current croplands under climate change[J].Nature Communications,2016,7:12608
[11]吴文斌,唐华俊,杨鹏,等.基于空间模型的全球粮食安全评价[J].地理学报,2010,65(8):907-918WU W B,TANG H J,YANG P,et al.Model-based assessment of food security at a global scale[J].Acta Geographica Sinica,2010,65(8):907-918
[12]吴文斌,余强毅,陆苗,等.耕地复种指数研究的关键科学问题[J].中国农业科学,2018,51(9):1681-1694WU W B,YU Q Y,LU M,et al.Key research priorities for multiple cropping systems[J].Scientia Agricultura Sinica,2018,51(9):1681-1694
[13]卞新民,冯金侠.多元多熟种植制度复种指数计算方法探讨[J].南京农业大学学报,1999,22(1):11-15BIAN X M,FENG J X.Method of calculating cropping system index of diversified multiple cropping system[J].Journal of Nanjing Agricultural University,1999,22(1):11-15
[14]左丽君,张増祥,董婷婷,等.耕地复种指数研究的国内外进展[J].自然资源学报,2009,24(3):553-560ZUO L J,ZHANG Z X,DONG T T,et al.Progress in the research on the multiple cropping index[J].Journal of Natural Resources,2009,24(3):553-560
[15]Devendra C,Thomas D.Smallholder farming systems in Asia[J].Agricultural Systems,2002,71(1/2):17-25
[16]中华人民共和国农业部粮食作物生产局.改变耕作制度、扩大复种面积[M].北京:农业出版社,1958Department of Food Crop Production,Ministry of Agriculture of the People’s Republic of China.Changing Farming System and Expanding Multiple Cropping Area[M].Beijing:Agricultural Press,1958
[17]康清林,李春蕾,张玉虎.2001-2010年江苏省复种指数变化及其影响因子分析[J].首都师范大学学报:自然科学版,2017,38(5):86-94KANG Q L,LI C L,ZHANG Y H.The cropping index change and impact factor analysis in Jiangsu Province between 2001 and 2010[J].Journal of Capital Normal University:Natural Science Edition,2017,38(5):86-94
[18]李阔,许吟隆.适应气候变化的中国农业种植结构调整研究[J].中国农业科技导报,2017,19(1):8-17LI K,XU Y L.Study on adjustment of agricultural planting structures in China for adapting to climate change[J].Journal of Agricultural Science and Technology,2017,19(1):8-17
[19]刘巽浩.耕作学[M].北京:中国农业出版社,1994LIU X H.Farming Science[M].Beijing:China Agriculture Press,1994
[20]李晶,任志远.基于SPOTNDVI的陕西省耕地复种指数时空变化[J].干旱区资源与环境,2011,25(10):86-91LI J,REN Z Y.The monitoring for cropping index of arable land in northwest region using SPOTNDVI-A case of Shaanxi Province[J].Journal of Arid Land Resources and Environment,2011,25(10):86-91
[21]田罗,周文佐,何万华,等.2000-2016年四川省耕地种植指数时空变化及其自然潜力分析[J].中国生态农业学报,2018,26(8):1206-1216TIAN L,ZHOU W Z,HE W H,et al.Spatio-temporal evolution and potential analysis of cropping index in Sichuan Province during 2000-2016[J].Chinese Journal of Eco-Agriculture,2018,26(8):1206-1216
[22]徐国鑫,金晓斌,宋佳楠,等.耕地集约利用对粮食产量变化影响的定量分析--以江苏省为例[J].地理研究,2012,31(9):1621-1630XU G X,JIN X B,SONG J N,et al.The impact of intensive use of agricultural land on grain yields:A case study of Jiangsu Province[J].Geographical Research,2012,31(9):1621-1630
[23]张倩,许泉,王全忠,等.补贴政策与农户稻作制度选择--基于湖南省微观调研的证据[J].产业经济研究,2016,(6):89-99ZHANG Q,XU Q,WANG Q Z,et al.The effect of subsidy policy on rice planting pattern choices of peasant households:Evidence from micro-investigation in Hunan Province[J].Industrial Economics Research,2016,(6):89-99
[24]闫慧敏,刘纪远,曹明奎.近20年中国耕地复种指数的时空变化[J].地理学报,2005,60(4):559-566YAN H M,LIU J Y,CAO M K.Remotely sensed multiple cropping index variations in China during 1981-2000[J].Acta Geographica Sinica,2005,60(4):559-566
[25]张乐勤,陈素平,陈发奎.基于边际模型的中国城镇化演进对耕地影响极限研究[J].中国生态农业学报,2014,22(7):837-842ZHANG L Q,CHEN S P,CHEN F K.A marginal model-based study of the ultimate influence of China’s urbanization evolution on cropland[J].Chinese Journal of Eco-Agriculture,2014,22(7):837-842
[26]梁守真,马万栋,施平,等.基于MODIS NDVI数据的复种指数监测--以环渤海地区为例[J].中国生态农业学报,2012,20(12):1657-1663LIANG S Z,MA W D,SHI P,et al.Monitoring multiple cropping index using MODIS NDVI data:A case study of Bohai Rim[J].Chinese Journal of Eco-Agriculture,2012,20(12):1657-1663
[27]梁书民.我国各地区复种发展潜力与复种行为研究[J].农业经济问题,2007,28(5):85-90LIANG S M.Probing potentials of multiple cropping in the selected provinces in China[J].Issues in Agricultural Economy,2007,28(5):85-90
[28]曲福田,吴郁玲.土地市场发育与土地利用集约度的理论与实证研究--以江苏省开发区为例[J].自然资源学报,2007,22(3):445-454QU F T,WU Y L.Theoretical and empirical study on the land market and land use intensity:A case of the development zones in Jiangsu Province[J].Journal of Natural Resources,2007,22(3):445-454
[29]杨红梅,刘卫东,刘红光.土地市场发展对土地集约利用的影响[J].中国人口·资源与环境,2011,21(12):129-133YANG H M,LIU W D,LIU H G.Effects of land market development on land use intensity[J].China Population,Resources and Environment,2011,21(12):129-133
[30]崔宁波,张正岩.临储政策取消下玉米种植结构调整的影响因素与收入效应--基于黑龙江省镰刀弯地区调查数据的分析[J].商业研究,2017,59(11):153-163CUI N B,ZHANG Z Y.Influence factors and income effects of the adjustment of corn planting structure under the abolition of temporary storage policy:An analysis based on the survey data of sickle bend area in Heilongjiang Province[J].Commercial Research,2017,59(11):153-163
[31]STOCK J H,YOGO M.Testing for weak instruments in linear IV regression[M]//ANDREWS D W K,STOCK J H.Identification and Inference for Econometric Models Essays in Honor of Thomas Rothenberg.Cambridge:Cambridge University Press,2002
[32]彭继权,吴海涛,孟权.家庭生命周期、社会资本与农户生计策略研究[J].中国农业大学学报,2018,23(9):196-217PENG J Q,WU H T,MENG Q.Study on family life cycle,social capital and rural households’livelihood strategy[J].Journal of China Agricultural University,2018,23(9):196-217
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |