Analysis Of Obstacle Factors Of Continuous Soybean Cropping And Control Measures In Heilongjiang Province

Aimed at the extension of continuous soybean cropping area and its side-effects, in this work, soil and plant samples were collected from 100 sampling points in continuous soybean fileds guided by GPS, then the available nutrients of soil samples and the plant nutrients were analysed. A spatial distribution map was made out of the date. And the experiments of screening the environment-friendly tillage practices to reduce the barriers of continuous soybean were conducted in different continous cropping years and different nutrent content fields. The results showed that:Soil available potassium ranges from 140 mg kg-1 to 250 mg kg-1 in the continuous soybean fields in sampling areas. Potassium deficient areas were mainly distributed in Shuangcheng, Acheng, and Binxian regions. At the same time, rates of potassium fertilizer application were not sufficient in these areas, and potassium deficiency symptoms were often found in the field. Soil phosphorus is universally deficient, but the deficiency symptoms had not been found in the filed. Deficiencies symptoms of iron, Manganese and Zinc, related to soil pH, were also observed mainly in Mingshui and Harbin area. The mineral nutrients are obviously correlated in these soils each other.Trace elements in soybean cultivation can not be ignored, Zn in the soil can promote plant for nitrogen, phosphorus, potassium uptake, and plant nitrogen, phosphorus and potassium content showed a significant positive correlation, and direct impact on plant chlorophyll content, plant height and yield. Potassium and soybean growing a good correlation, soil available K content in the range of 180 mg/kg～240mg/kg, increased potassium can significantly improve soybean yields. Soybean root rot and soybean cyst nematode, even in the serious plot; soil available nitrogen, available phosphorus and organic matter content of soil and soybean yields were positively correlated. Through soybean production and soil trace elements in correlation analysis showed that soybean yield and soil Zn, Mn, Fe, Ca was positively correlated.Though investigation and analysis, main factors resulted in yield decrease has been found, including soybean root rot and soybean cyst nematode, high soil pH, soil potassium deficient and disbalance of trace elements and so on, actually disscientific customs of fertlizer application is one of main factors led to decrease yeild.Even by reducing soybean agronomic measures for screening, the results show that the selection of resistant varieties, seed coating and fertilizer proper ratio is an important factor in yield formation. K is to promote the growth and development of soybean plants to improve disease resistance of soybean an important factor; seed coating or seed treatment application of agents are effective measures to reduce seedling diseases.