Study On Fertilizer Response And Optimum Fertilizer Rate By Soil Testing And Fertilizer Recommendation Experiments

Together with the soils testing and fertilizer recommendation in Hubei province, the "3414" field trials which were conducted from 2005 to 2007 in Enshi, Nanzhang, Tianmen,Xiantao cities were studied. To give a better help for agricultural production, the study analyzed the effects of corps,fertilization, soils fertility,crops rotations and soil local types on yield and use efficiency of fertilizers, and tried to establish the equation of fertilizer response for rice, maize,rape,wheat. Main results are as follows:1 .The change ranges of use efficiency of nitrogen, phosphate, potash fertilizers for rice,maize,wheat,rape were 13.29%-31.44%,21.01%-33.55%,38.46%-58.45% respectively. Effects of fertilizers on yield of wheat and rape were superior to rice and maize. The increased yield of crops was the highest when nitrogen, phosphate, potash fertilizers were applied together, The main factor was nitrogen, secondly phosphorus and potassium. Compared to regular fertilization, The use efficiency of nitrogen, phosphate, potash fertilizers of formula fertilization increased. Especially potassium increased highly than nitrogen and phosphorus, and the crops yields with 1 kg fertilizer nutrients increasing in formula fertilization increased for rice, wheat, rape, maize.2.Through the equation of "3414" fertilizer effect experiment, the results showed that, the optimum nitrogen dosages of rice in high, middle, low fertility soils respectively were 31.36kg/hm~2,218.36kg/hm~2,139.5kg/hm~2,the optimum phosphate dosages respectively were 135kg/hm~2,47.09 kg/hm~2,68.15kg/hm~2, the optimum potash dosagesrespectively were 99.68kg/hm~2,63.28 kg/hm~2,84.18kg/hm~2; the optimum nitrogen dosages of maize in high, low fertility soils respectively were 191.4kg/hm~2,199.57kg/hm~2,the optimum phosphate dosages respectively were 39.10kg/hm~2,71.82kg/hm~2, the optimum potash dosages respectively were 135-202.5kg/hm~2,28.32kg/hm~2; the optimum dosages fo nitrogen, phosphate, potash fertilizers were 186.63kg/hm~2,64.56kg/hm~2,76.20kg/hm~2 for wheat respectively ; 147.59kg/hm~2,76.32kg/hm~2,18.67kg/hm~2 for rape respectively.3.The optimum dosage of nitrogen fertilizer was 199kg/hm~2,150kg/hm~2 respectively for rice and wheat, use efficiency of nitrogen fertilizer and crops yield were quadratic parabolic curve which increased originally then decreased respectively ,with the application of N increasing for wheat and rice; The optimum dosage of nitrogen fertilizer was 114kg/hm~2,190kg/hm~2 respectively for maize and rape, with the application of N increasing, crops yield increased originally then decreased respectively ,but use efficiency of nitrogen fertilizer decreased linear; with the application of P increasing, excessive fertilizer lows crops field remarkably and use efficiency of phosphate fertilizer, theoptimum dosage of phosphate fertilizer was 66kg/hm~2,82kg/hm~2,25kg/hm~2,54kg/hm~2 for rice,maize,rape and wheat; the optimum dosage of potash fertilizer was 80kg/hm~2,75kg/hm~2,46kg/hm~2,120-180kg/hm~2 for rice,rape,wheat and maize.4. The wheat-rice rotations was superior to the rape-rice rotations on use efficiency of fertilizers and the increased yield effects of every 1 kg fertilizers. The wheat-maize rotations was superior to the potato-maize rotations on use efficiency of fertilizers and the increased yield effects of every 1 kg fertilizers.5.Use efficiency of fertilizers and the increased yield response of fertilization decreased with soils fertility increasing ,the ear few and available ear of yield components had greater effects on rice yield than other factors of yield components, and the ear few was important in maize yield increasing responses.6. The soil types in field trials of different crops were studied, the results showed that use efficiency of fertilizers were different in different soils local types for the same crop, the effects of yield increasing were not significantly different in 2 different soils local types for rape and maize, however, the effects of yield increasing were significantly different in 4 different soils local types for rice.