Effects Of Monitoring Fertilization On Wheat Yield, Soil Fertility And Environment On Dryland

There is a common phenomenon of single and excessive fertilization in most areas ondryland in northwest of China, where the soil nutrient is deficient, low productivity and lackof rational fertilization technology and accurately calculable method. So, based on theperspective of nutrient balance, a method which named “monitoring residual nitrate N in1msoil layer” was proposed to recommend N fertilizer, and combined with the method ofkeeping constant application rate of phosphorus and potassium by monitoring available P andK. And a field experiment was conducted in Yangma village of Yongshou Shaanxi Provinceduring September2009to September2011to study the effects of monitoring fertilization onwinter wheat yield, nutrient efficiency, soil fertility and environmental effects. The mainresults were as follow:1. Nitrogen fertilizer application rate of the treatment that used the method of monitoringresidual nitrate N in1m soil layer (monitoring fertilization) was112kg/ha, which reduced by34.0%compared with the traditional farmers fertilization treatment. Grain yield of winterwheat in monitoring fertilization treatment increased by13.4%, partial factor productivity(PFP) of nitrogen and phosphorus fertilizer increased by141.1%and29.6%, respectively, netincome increased by1191RMB(yuan)/ha. It is noted that monitoring fertilization couldincrease grain yield, fertilizer use efficiency and economic benefits, and reduce fertilizerinputs and costs. Compared with the treatment of non K fertilizer input, potassium fertilizerapplication did not increase the yield, but increased the potassium uptake by winter wheat.2. Compared with the traditional farmers fertilization treatment, soil nitrate content of themonitoring fertilization treatment was significantly lower, which suggested that monitoringfertilization could reduce the risk of nitrate leaching. While, the ammonium content ofdifferent treatments was very low and remained at a stable level. Available P content in0-20cm soil layer declined in the harvest time in2009-2010but increased in the harvest time in2010-2011, and reached the medium level of10-15mg/kg. Compared with the treatment ofnon potassium fertilizer application, potassium fertilizer application could improve theavailable K content in0-40cm soil layer, reaching the moderate level of90-120mg/kg.3. Compared with the traditional farmers fertilization, the residual nitrate nitrogen in 0-100cm soil layer in monitoring fertilization treatment decreased by60.6%. Before sowingof the next season, nitrate nitrogen content in0-100cm soil layer increased in monitoringfertilization treatment, but that increased in the traditional farmers fertilization treatments in0-100cm soil layer below. The organic nitrogen mineralization rate of monitoring fertilizationtreatment in0-100cm soil layer during summer fallow period in2010was57.6kg/ha, butthere was almost no mineralization in the traditional fertilization treatment. In the two-yearexperiment, monitor fertilization increased nitrate accumulation by an average of5.9kg/ka in0-100cm soil layer, while the traditional farmers fertilization reduced by27.4kg/ha.Thismeant that27.4kg/ha nitrate was might be leached below1m depth soil layer, which showedthat monitoring fertilization was effective to reduce the nitrate leaching.