spatial and temporal variations of crop fertilization and soil fertility in the loess plateau in china from the 1970s to the 2000s. | increased fertilizer input in agricultural systems during the last few decades has resulted in large yield increases, but also in environmental problems. we used data from published papers and a soil testing and fertilization project in shaanxi province during the years 2005 to 2009 to analyze chemical fertilizer inputs and yields of wheat (triticum aestivum l.) and maize (zea mays l.) on the farmers' level, and soil fertility change from the 1970s to the 2000s in the loess plateau in china. the ... | 2014 | 25380401 |