Since the Grain for Green(GFG)program was implemented in 1999,most steeply sloping farmlands in the Loess Plateau of China have been returned to forestland and grassland.To understand its impact on the food production...Since the Grain for Green(GFG)program was implemented in 1999,most steeply sloping farmlands in the Loess Plateau of China have been returned to forestland and grassland.To understand its impact on the food production,this study analyzed the spatiotemporal changes of food crop production(FCP)in the plateau and quantified the contribution of sown area and yield changes to the total FCP during 1998–2014 using factor decomposition models,and then discussed the impact of GFG program on the FCP based on literature data.With the implementation of GFG program,total sown area in the Loess Plateau quickly deceased by 17.3%from 1998 to 2003,and then gradually restored to 1.03×107 hm2 in 2010.Thereafter,it slightly decreased to 1.02×107 hm2(94.6%of the area in 1998)in 2014.By contrast,total FCP generally showed an apparent growth trend,averagely increased by 1.71%per year in the whole plateau during 1998–2014.This increase was jointly contributed by the improved yield of individual crops,and the adjustment of cropping structure,i.e.,the expansion of high yield maize crop.The factor decomposition analysis results indicate that the sown area shrinkage only reduced the growth rate of total FCP by 0.29%per year during 1998–2014,although a significant impact was found for the early stage of 1999–2003.The results suggest that the implementation of GFG program would not induce an obvious risk of the food security.Therefore,it is suggested that the GFG program should be set as a long-term strategic policy,by not only supporting the conversion of slope farmlands,but also helping local farmers to seek sustainable ways of land use to improve the income and livelihood.It can be combined with the poverty eradication program,to simultaneously achieve the national goals of ecological civilization building and the livelihood improvement of rural people in the Loess Plateau.Considering rainfall limitation,the conversion of slope farmlands should be prioritized to grasslands.展开更多
[Objective] The aim was to study on response of N2O emissions of farm- land ecosystem on temperature rising. [Methed] In farmland ecosystem in Huaibei City in Anhui Province, N2O emission by twelve varieties of crop o...[Objective] The aim was to study on response of N2O emissions of farm- land ecosystem on temperature rising. [Methed] In farmland ecosystem in Huaibei City in Anhui Province, N2O emission by twelve varieties of crop on temperature was researched with DeNitrification-DeComposition (NDC). [Result] Response of dry- land crop on temperature rising can be divided into three categories, as follows: The first category, N2O emission of crop changed little during the temperature increasing, for example, from 0 to 3 %;, the emissions by potatoes, cotton, maize and rapeseed increased little and decreased little when temperature changed from 1.5 to 3 ℃. Crops of the second category declined with temperature increasing in N2O emission, for example, N2O emission decreased by 8.1% with temperature increasing from 0 to 3 ℃, including sugar cane, tobacco, wheat, soybean and pea. In third category, N2O emission of crop grew with temperature increasing, for example, the emission of rice, vegetables and fruit trees increased by 22.8% when the temperature grew from 0 to 3 ℃. [Conclusion] The research indicated that N2O emission in ecosystem of drv farmland increased little with temoerature risina.展开更多
基金jointly supported by the National Natural Science Foundation of China(41671093)the National Key R&D Program of China(2017YFA0604701,2012CB955304)
文摘Since the Grain for Green(GFG)program was implemented in 1999,most steeply sloping farmlands in the Loess Plateau of China have been returned to forestland and grassland.To understand its impact on the food production,this study analyzed the spatiotemporal changes of food crop production(FCP)in the plateau and quantified the contribution of sown area and yield changes to the total FCP during 1998–2014 using factor decomposition models,and then discussed the impact of GFG program on the FCP based on literature data.With the implementation of GFG program,total sown area in the Loess Plateau quickly deceased by 17.3%from 1998 to 2003,and then gradually restored to 1.03×107 hm2 in 2010.Thereafter,it slightly decreased to 1.02×107 hm2(94.6%of the area in 1998)in 2014.By contrast,total FCP generally showed an apparent growth trend,averagely increased by 1.71%per year in the whole plateau during 1998–2014.This increase was jointly contributed by the improved yield of individual crops,and the adjustment of cropping structure,i.e.,the expansion of high yield maize crop.The factor decomposition analysis results indicate that the sown area shrinkage only reduced the growth rate of total FCP by 0.29%per year during 1998–2014,although a significant impact was found for the early stage of 1999–2003.The results suggest that the implementation of GFG program would not induce an obvious risk of the food security.Therefore,it is suggested that the GFG program should be set as a long-term strategic policy,by not only supporting the conversion of slope farmlands,but also helping local farmers to seek sustainable ways of land use to improve the income and livelihood.It can be combined with the poverty eradication program,to simultaneously achieve the national goals of ecological civilization building and the livelihood improvement of rural people in the Loess Plateau.Considering rainfall limitation,the conversion of slope farmlands should be prioritized to grasslands.
基金Supported by National Natural Science Foundation of China(40930530)~~
文摘[Objective] The aim was to study on response of N2O emissions of farm- land ecosystem on temperature rising. [Methed] In farmland ecosystem in Huaibei City in Anhui Province, N2O emission by twelve varieties of crop on temperature was researched with DeNitrification-DeComposition (NDC). [Result] Response of dry- land crop on temperature rising can be divided into three categories, as follows: The first category, N2O emission of crop changed little during the temperature increasing, for example, from 0 to 3 %;, the emissions by potatoes, cotton, maize and rapeseed increased little and decreased little when temperature changed from 1.5 to 3 ℃. Crops of the second category declined with temperature increasing in N2O emission, for example, N2O emission decreased by 8.1% with temperature increasing from 0 to 3 ℃, including sugar cane, tobacco, wheat, soybean and pea. In third category, N2O emission of crop grew with temperature increasing, for example, the emission of rice, vegetables and fruit trees increased by 22.8% when the temperature grew from 0 to 3 ℃. [Conclusion] The research indicated that N2O emission in ecosystem of drv farmland increased little with temoerature risina.