| BeiAn city is one of the main soybean production regions in Hilongjiang province, with tipical black soil region and fertile soil. Soybean planting area accounts for more than 50% of the cultivated land area in BeiAn city. Continual unbalanced fertilization practices not only reduce the fertilizer utilization ratio, increased agricultural production costs, also can't maintain in a higher level on soybean production, and even cut year by year, which have influenced seriously the farmers' income, hampered agricultural sustainable development.According to the phenomenon of unreasonable fertilization applicatio at present, In this paper, Soil N, P, K nutrient content character was grasped by the soil sampling test, Appropriate NPK fertilizers and matching was knowed, soybean fertilization parameters and fertilization model of different regions in BeiAn city were made certain by soybean field experiments from the year 2007 to 2009. Through these studies, scientific theory and technology support were provided for soybean balanced fertilization in BeiAn city. The main research results are as follows:1. Compared to the results of second soil survey, soil fertility decreased significantly by analyzing 8000 soil samples of year 2007 to 2009 from 9 towns of BeiAn city. The reason of which was that organic fertilizer was ignored by peasant.2. Compared to the results of second soil survey, different types of soil alkali nitrogen content were declined.The order was boggy soil> dark brown earth> meadow soil> paddy soil> black soil.Different types of soil available phosphorus content were declined in addition to black soil. The order was boggy soil> paddy soil> meadow soil> dark brown earth. Different types of soil available potassiums content were declined. The order was dark brown earth> boggy soil>black soil> meadow soil> paddy soil.3. Soil alkali nitrogen content of BeiAn city was high levels.most of them was more than 150 mg/kg. Soil available phosphorus content of BeiAn city were higher, most of them was more than 20 mg/kg.4. Soybean production was increased significantly under the condition of reasonable N,P,K ratios,and it was influnced by no fertilizer and inbanlanced fertilizer.The order of contribution of N,P,K fertilizers to soybean production was N>K>P.5. Experiment results of BeiAn showed that range of variation of agronomic efficiency of N, P, K was larger extent. Agronomic efficiency of nitrogen was from 3.8 to 20.0 kg/kgN,average 10.5 kg/kgN; agronomic efficiency of phosphorus was from 0.8 to 10.5 kg/kg P2O5,average 4.8 kg/kg P2O5; agronomic efficiency of potassiums was from 1.1 to 13.1 kg/kg K2O,average 6.2 kg/kg K2O.6. The content of soil alkali nitrogen available phosphorus and available potassiums of BeiAn city were divided into five levels according to soybean relative yield. Abundance or absence of soil alkali nitrogen content was determined by soybean relative yield of 50%,65%,75%,85%. Soil available phosphorus and available potassiums content were determined by soybean relative yield of 75%,80%,85%,90%.Soil alkali nitrogen content critical value was 72 mg/kg,150 mg/kg,244 mg/kg and 397 mg/kg. Soil available phosphorus content critical value was 11 mg/kg,19 mg/kg,34 mg/kg and 61 mg/kg.Soil available potassiums content critical value was 118 mg/kg,152 mg/kg,197 mg/kg and 255 mg/kg.7. Soil alkali nitrogen content of BeiAn city was higher, and more than 85% was at high levels or very high levels. Soil available phosphorus content was higher, and more than 70% was at high levels or very high levels. Soil available potassiums content were lower and more than 80% was at low levels or very low levels and middle levels.There was some difference in content of available N,P and K among regions,8. Different regions of BeiAn city has different fertilizing amount, and has different fertilization model. The range of N,P,K fertilizer was N from 22.4 kg/hm2 to 67.5 kg/hm2; P2O5 from 36.6 kg/hm2 to 90.0 kg/hm2, K2O from 3.3 kg/hm2 to 112.5 kg/hm2.The average of best fertilizing amount was N 48.0 kg/hm2,P2O567.2 kg/hm2,K2O 73.5 kg/hm2.Soybean upper limit fertilizing amount was N 67.5 kg/hm2,P2O590.0 kg/hm2,K2O 112.5 kg/hm2 in black soil of BeiAn city. Fertilizing amount can be induced on the basis of soil nutrient content in order to increase economic benefit.9. The range of nitrogen utilization efficiency was 21.2-39.7%, average 32.0%; phosphorus utilization efficiency was 12.9-20.7%, average 16.1%; potassiums utilization efficiency was 34.6-47.3%, average 40.9%. N, P2O5, K2O contents were respectively 7.14kg,1.84kg and 4.18kg in 100 kilogram soybean. Nitrogen, phosphorus and potassiums utilization efficiency have large improving extent on planting soybean in BeiAn city. |
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