Study On Cultivated Soil Quality Evaluation In Hailun Of Heilongjiang Province

Soil quality is.soil which can provide necessary nutrition, production of biological substances in the ecological system:the capacity of degradation, purification and keeping ecological balance,;comprehensive measures which can influence and promote plant, animal and human safety and health. In short, soil quality is composed of soil fertility quality, soil environment quality and soil health quality. Soil quality is the capacity of soil which can support biological productivity, clean up the environment and improve human health, animal and plant and so on. Soil quality is the core of modern soil science.This study is about cultivated soil. So it focuses on the research of soil fertility quality. Soil fertility quality is capacity of soil which can supply nutrients for all kinds of crops. Black soil fertility is also capacity of black soil which can supply nutrients for all kinds of crops..Fertility quality directly affects agricultural production and crop yield. On the contrary, kinds of agricultural measures on soil influence the soil fertility quality too. Good agricultural measures or fertilization can improve the quality of soil fertility quality. In despite of varieties of crop, soil quality is the first factor to improve the yield per unit area.. Excellent soil quality, can provide enough balanced nutrients, the right amount of soil organic matter, and good soil structure and deep soil layers,to maintain the coordination of water and air. So good soil quality is not only the base for access to high-yield but also improvement of the soil resistance to corrosion and erosion.In this paper, the soil of cultivated land in Hailun of Heilongjiang province is the research object.The distribution of indicators which have effects on soil quality is classified and evaluated, so that soil quality is fuzzy evaluated to look for the relationship between soil quality and crop yield, and soil constraint factors.Evaluated results are as follows:(1)Soil types have significant effects on crop yield. The distribution rule of crop yield on measured field is as follows:meadow soil of thick layer>black soil of middle layer> black soil of thick layer>meadow soil of middle layer>black soil of thin layer.(2) Minimum data set (MDS) is filtered out to establish the cultivated soil quality evaluation system of a clear biological significance and indicator weights.This evaluation is based on soil quality and crop yield, Both soil quality and crop yield are classified to compare with each other. Without 15 abnormal points,linear regression equation of soil quality and crop yield:y=1955.8x+1460.5,R2=0.2777,Soil quality and crop yield have good correlation with each other according to evaluated result. So, the methodology of fuzzy evaluation is suitable to take farmland soil quality assessment.(3)The organic matter content of black soil of this region is high. Its average content is 4.86%, but less than the second soil survey average result 6.06%。So, soil organic matter content has declined in recent years.More organic fertilizer should be applied and straw should be returned to farmland to maintain soil fertility of this region.(4) Available phosphorus content is higher than other regions.Its average content is 40.2mg/kg. The index of correlation between soil available phosphorus and crop yield is 0.237, and the correlation is significant correlation. Low temperature is the main cause of phosphorus deficiency of crop in this area. So, it is relatively normal that Black soil phosphorus content higher than that of other regions. But more research needs to done about how much phosphate fertilizer should be applied. In some soil of these farmland, available phosphorus content is more than 100 mg/kg. Some attention about available phosphorus content must be taken by the relevant department.(5)Available potassium content is high in this region, and its average content is 161.3mg/kg. The index of correlation between soil available potassium and crop yield is 0.237, and the correlation is highly significant correlation. High potassium content(>220 mg/kg) in soil is beneficial to soy, corn, high and stable yield. Under the circumstance of Low temperature, low light, rain-fed agriculture, Available potassium of high levels enhance crop resistance to frost damage, drought and storm. Therefore high and stable yield in the region can not always rely on the depletion of soil potassium fertility. Most potassium absorbed by crops is in the straw. So straw returning to soil can more easily maintain available potassium at a high level of soil.Therefore, it is one of the key measures to return straw to field to maintain soil available potassium.(6) The index of correlation between soil available boron and crop yield is 0.577. And the correlation is highly significant correlation. When soil available boron content is less than 0.5 mg/kg, crop yield is not too high. Soybean is the main crop in this region. Because soybean is one type of crops which need high boron, soil available boron content has been a limiting factor of soybean growth.Available B of soil is one of the factors which have effects on crop yield. Usually hot water soluble boron soil> 0.5mg/kg will not be considered boron deficiency, but available B in black soil region is relatively low due to low soil temperature. Critical value of soil boron may be higher than that of other southern soil.It is worth taking enough attention to boron fertilizer application.