Changes in regional grain yield responses to chemical fertilizer use in china over the last 20 years

A major challenge facing China is to meet the increasing food demand of its growing population in the face of decreasing arable land area, while sustaining or improving soil productivity and avoiding adverse environmental impacts from intensive agriculture. This study uses data from China Statistical Yearbooks to analyze trends in regional soil productivity and grain yields in the major grain-producing regions in North China (NC), Northeast China (NE), East China (EC), Central China (CC), and Southwest China (SW), associated with regional fertilizer use and annual climate variation in rainfall and mean temperature over the 20 years. During 1992-2012, the average fertilizer increase rates (in kg ha-1 year-1) were in the order of regions CC (6.6) > NC (4.8) > EC (2.4) > SW (2.1) > NE (1.3), while yield responses to fertilizer use (with regression model coefficients, in kg kg-1) were in the order: SW (-0.9) < CC (1.1) < NC (1.7) < EC (5.7) < NE (9.3), showing higher yield responses to fertilizer use for NE and EC than for other regions. The changes in regional grain yields also showed higher yield responses to soil-based productivity for NC, CC, and SW, or to annual climate variability for CC than for other regions, indicating that other factors (such as inherent soil productivity or annual climate variability could be more important than fertilizer in affecting yields. The strategies for regulating nutrient management are needed considerably based on regional indigenous soil nutrient supply under varying regional climate conditions.</p

Factors controlling regional grain yield in China over the last 20 years

International audienceFood production is highly dependent on regional yields of crops. Regional differences in grain yields could be due to fertilizer management and climate variability. Here, we analyze trends of grain yields in North China, Northeast China, East China, and Central and Southwest China from 1992 to 2012, using the Chinese statistical yearbooks. We estimate the major factors influencing yield by regression analysis. Results show that fertilizer indices were 40 % for Northeast China, 36 % for East China, 9 % for North China, and 6.8 % for Central and Southwest China. Soil indices were 67 % for Northeast China, 14 % for East China, 90 % for North China, and 6 % for Central and Southwest China. The indices of annual mean temperature were positive for Central and Southwest China (72 %) and East China (39 %), but negative for Northeast China (−15 %) and North China (−16 %). Soil factors explained 80 % of yield variation in North China. Annual mean temperature explained 80 % of yield variation in Central and Southwest China

Balanced N and C input recommendations for rain-fed maize production in northern China based on N balances and grain yields

BACKGROUND: This study aimed to assess longer-term (1993-2009) effects of combined applications of fertiliser, maize stover, and cattle manure on maize yields, partial nitrogen (N) and carbon (C) balances, and water and N-use efficiencies, to guide N and C input recommendations for rain-fed maize production in northern China. RESULTS: The field trial, with three factors at five levels and 12 treatments, was conducted at Shouyang Dryland-Farming Experimental Station, Shanxi, China. Data analysis revealed higher N balances but lower C balances significantly occurred in a dry year than in a wet year. Positive N balances related to higher N inputs resulted in higher soil available N, even downward to deep layers with increasing N inputs, while positive C balances due to higher C inputs could be benefit to increase soil organic C. Based on partial N balances and grain yields, N and C inputs at ranges of 100kg N ha-1 and 1.9-2.9Mg C ha-1 could be recommended for target yields of 6.7-7.2Mg ha-1 in rain-fed maize production. CONCLUSION: The study suggests that N balances close to neutral be given priority to improving N-use efficiency, and more positive C balances also be important for sustaining target yields and soil fertility levels