Soil Organic Matter, Phosphorus And Potassium Fertility Of Different Fertilization Systems And Its Effect On Crop Yield

Based on the long-term location experiment which lasted for 20 years in Yucheng site of CAAS on salinized fluvo-aguic soil, the research explored the organic matter, phosphorus and potassium fertility characters of different fertilization systems and its effect on crop yield. The main results are as follows:1 The soil organic carbon, humus and recomb humus contents were improved by long-term fertilization obviously. Their compositions contents and loose/tight were improved also at the same time. The soil organic carbon, humus and recomb humus contents of long-term high use level of organic manure were the highest and higher than other treatments significantly.2 The soil total P and available P content could be improved by long-term use of fertilizer. Thereinto, the soil total P and available P content of high organic manure treatment was highest than other treatments, and its content reached 1455mg·kg-1 and 541mg·kg-1 respectively. The soil organic P and inorganic P total content of each fertilizer treatment was higher than CK markedly. Under the same nitrogen level, the soil organic P and inorganic P total content of organic manure treatment was higher than chemical fertilizer treatment obviously. The inorganic P was the main form P in arable soil which was 75%~84% of soil total P.3 Ca10-P, Ca8-P and O-P was the main form of soil inorganic P, and the effect of long-term use of fertilizer on Ca10-P content was not obvious. The Ca2-P content could be increased considerably by the use of organic manure and its content was increasing with the use level of organic manure increasing. Chemical fertilizer had positive effect on soil P supplity ability to some extent, but the Ca2-P content was not influenced by the use level of chemical fertilizer. The effect of organic manure combined with chemical fertilizer treatment on Ca8-P content was better than conventional chemical fertilizer treatment.4 MLOP was the main form of soil organic P, and the effect of long-term use of organic manure on soil LOP and MLOP content was significantly and their contents were increasing with the use level of organic manure increasing. Chemical fertilizer treatment had little effect on soil LOP. The effect of organic manure combined with chemical fertilizer treatment on LOP content was better than conventional chemical fertilizer and organic manure treatment. The effects of different fertilization systems on soil MROP and HROP contents were similar with soil MLOP. And the effect of organic manure combined with chemical fertilizer treatment on soil MROP and HROP contents better than conventional chemical fertilizer treatment.5 Mineral potassium was the main form in soil potassium which was 92.60%~94.80% of total potassium, soil slowly available potassium was 4.76%~5.48% and available potassium was only 0.39%~1.09%. Compared with CK, the effects of different fertilization systems on soil total potassium content were not obvious.6 The long-term use of conventional organic manure, high organic manure, high chemical fertilizer could all improve soil available K and each form of total K content. The water soluble K content of chemical fertilizer lower than other fertilization treatment, and increasing amount of soil available K content and the each form of it of long-term were the most.7 Long-term use of conventional organic manure, high organic manure, high chemical fertilizer and organic manure combined with chemical fertilizer could improve the soil slowly available K and mineral K content in 0~20cm layer and soil slowly available K content was increasing with the use level of organic manure increasing. But the content of soil mineral K content showed the inverse trend.8 The wheat and maize yields of comparison was decreased quickly in 2~3 years from the experiment beginning, and then on low level all the while. The diversities of yield (wheat and maize) among fertilization treatments were not significant after about 15 years. The use of chemical fertilizer was important measure to maintain winter wheat steady and high yield, and the use of organic manure was crucial to improve summer maize yield and the ability of acclimatization under winter wheat-summer maize planting mode.