Spatial and Temporal Variations of Crop Fertilization and Soil Fertility in the Loess Plateau in China from the 1970s to the 2000s

Abstract

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 results showed that in different regions of the province, chemical fertilizer NPK inputs and yields of wheat and maize increased. With regard to soil nutrient balance, N and P gradually changed from deficit to surplus levels, while K deficiency became more severe. In addition, soil organic matter, total nitrogen, alkali-hydrolysis nitrogen, available phosphorus and available potassium increased during the same period. The PFP of N, NP and NPK on wheat and maize all decreased from the 1970s to the 2000s as a whole. With the increase in N fertilizer inputs, both soil total nitrogen and alkali-hydrolysis nitrogen increased; P fertilizer increased soil available phosphorus and K fertilizer increased soil available potassium. At the same time, soil organic matter, total nitrogen, alkali-hydrolysis nitrogen, available phosphorus and available potassium all had positive impacts on crop yields. In order to promote food safety and environmental protection, fertilizer requirements should be assessed at the farmers' level. In many cases, farmers should be encouraged to reduce nitrogen and phosphate fertilizer inputs significantly, but increase potassium fertilizer and organic manure on cereal crops as a whole.

Soil characteristics in the floodplains of Munawar Tawi in Rajouri, Western Himalayas, India

“…In the present study, pH, EC, primary and secondary macro and micronutrients vary significantly across seasons, localities and stage of the crop. Similar observations have been reported from studies elsewhere (Troelstra et al 1990;Wang et al 2014). This can be due to differences in the uptake of nutrients by the crops during growing and harvesting periods, rate of fertilizer inputs and other natural seasonal variations (Gornall et al 2010;Turner et al 2013).…”

“…In the case of Rajouri district, even after significant increase in addition of N and P, rice in the yields of rice, maize and wheat are insignificant. Incidentally, it is to be noted that higher addition of N and P could also lead to deficiency of K and micronutrients (Singh 2008;Wang et al 2014). The prescribed usage of N fertilizer in the crop vary but on an average it is 50 kg/ ha (Digest of Statistics 2012) lower than in plains (80 kg/ha, Parihar 2004).…”

Effects of Different Nitrogen Applications on Soil Physical, Chemical Properties and Yield in Maize (<i>Zea mays</i> L.)

“…Gong et al, (2013) also indicated that the contribution of soil productivity was significantly correlated with soil organic carbon, total nitrogen, available nitrogen, available phosphorus and available potassium in wheat with long-term soil fertility experiments [32]. The same results were reviewed from the 1970s to the 2000s in the Loess Plateau in China by Wang et al (2014) [33]. Results showed that changed trends of soil organic matter content under different treatments in two years were similar.…”

Moderate topsoil erosion rates constrain the magnitude of the erosion-induced carbon sink and agricultural productivity losses on the Chinese Loess Plateau

“…In 1950, when no mineral fertilizers were used (Zhu and Chen, 2002), nutrient losses by erosion likely exceeded nutrient supply. The reduction of relative nutrient losses is mainly due to the increase of nutrient inputs: the reduction of nutrient losses associated with a reduction of erosion rates is relatively less important (Wang et al, 2014a). The average TER on arable land is now close to what was long considered to be an acceptable soil loss tolerance level Renard et al, 1997).…”

“…Comparison of fertilizer inputs (N and P) and losses due to topsoil erosion (Tg) on arable land on the CLP in 1980 and 2000. Nutrients inputs were estimated by multiplying fertilizer input per unit area (kg ha −1 ) (Wang et al, 2014a) with the total cropland area (ha). Nutrient losses due to erosion were estimated by multiplying the amount of sediment mobilized by topsoil erosion and the nutrient content of topsoil under different land uses (Liu et al, 2013 (2000) amounts and relative losses of nutrients by erosion exceeded 50 % of the input at that time (Table 4).…”