10年来,我们一直坚持在小麦播前取土化验,从而摸索出了小麦播期供磷指标为40ppm,供氮指标为35ppm。化验结果表明,缺1ppm速效磷(P_2O_6)应补二铵500克或过磷酸钙1500克,缺1ppm速效氮应补尿素500克,或碳铵1500,速效磷测定:采用常规碳酸氢钠浸提法,速效氮采用简易还原测定法,实践证明在大田生产上应用是切实可行的。土壤肥力诊断目的在于解决土壤养分与作物生长的供需矛盾,在不同的生长发育阶段,掌握土壤养分含量,按作物需肥指标供肥,使每个地块的供肥水平达到作物需要的最适范围,从而使氮磷配 In the past 10 years, we have always insisted on taking soil tests before sowing, so we found out that the sowing date of wheat is 40ppm and the nitrogen supplying index is 35ppm. Test results show that the lack of 1ppm available phosphorus (P_2O_6) should make up 500 grams of diammonium or 1500 grams of superphosphate, the lack of 1ppm nitrogen should be supplemented urea 500 grams, or ammonium bicarbonate 1500, available phosphorus determination: using conventional sodium bicarbonate leaching Act, available nitrogen using simple reduction assay, the practice proved that the field production is feasible. The purpose of soil fertility diagnosis is to solve the contradiction between supply and demand of soil nutrients and crop growth. At different stages of growth and development, soil nutrient content is grasped, and fertilizer is needed according to the fertilizer requirement of crops, so that the fertilizer supply level of each plot reaches the optimal crop requirement Range, so that nitrogen and phosphorus with