Effects Of Continuous Application Of Digested Pig Biogas Slurry On Rape Yields、Rapeseed Quality And The Accumulation Effect Of Soil Quality Under Rich-rape Rotation Mode

Biogas slurry is a renewable resource, contains rich NPK nutrient elements, etc. Biogas slurry of agricultural application can meet the demand of crop nutrition, reduce agricultural production costs, increase economic efficiency.It is an effective way to promote agricultural efficiency, improving production the conditions, establish ecological agriculture, the development of green food. Also it can effectively solve the problem of biogas slurry resource utilization, and change waste material into things of value, provide the powerful guarantee for sustainable agricultural production.In order to study the effects of continuous application of digested pig biogas slurry on rape yields、rapeseed quality and the accumulation effect of soil quality under rich-rape mode, we designed a field experiment that plant rape with different application of biogas slurry in three years on Guyi Town, Qionglai City, Sichuan Province. It could determine the biogas slurry long-time agricultural use of feasibility and the best content of applying. Through the fiel tests, it could provide certain theoretical basis for the biogas slurry of effectively address and long-time agricultural use. The results of this study were as follows:1. The optimum application rate of biogas slurry considering improving the high yield and high quality of rape.Three years field experiments showed that this study Biogas slurry continuously plowing can effectively improve the yield and improving the quality of rapeseed, rape and to a certain extent, improve the rape the mineral elements content of grains, reduce the heavy metal content of rape seeds.But Biogas slurry amount of different influence on rape the indicators are also different, when applying Biogas slurry content in 101250-183500 kg-hm"2, within the scope of rapeseed physiological indexes in the best level;When applying Biogas slurry content in 101250-132500 kg-hm"2 range, at the same time control the dosage of basal around 37% can promote rape growth and development, good seedling, at around 47% can increase in the amount of fat rape yield; When applying Biogas slurry content in 101250-149500 kg·hm-2, within the scope of rapeseed NPK content had a higher level;When applying Biogas slurry content in 101250-132500 kg·hm-2, within the scope of rapeseed have best nutrition index;When applying Biogas slurry content in 90000-132500 kg·hm-2, within the scope of rapeseed mineral elements content had a higher level; When applying Biogas slurry content in 22500-132500 kg·hm-2 range, can keep rapeseed heavy metal content in lower level;In the control range of applying Biogas slurry content at the same time, the experimental results showed that applying Biogas slurry content in different growth period seems different, will affect the difference of each index in rapeseed, so choose the suitable stage seems to affect the quality of rapeseed has a very important role;Rapeseed safety evaluation result of heavy metals, as the amount of Biogas slurry not into, can increase the risk of heavy metal pollution in rape seed, therefore control at a lower level of Biogas slurry seems to reduce the risk of pollution.In conclusion can be concluded that by applying Biogas slurry content and rape relationship and influence of the indicators, when applying Biogas slurry content control in 101250-132500 kg·hm-2 within the scope of basal dosage at about 37%, seedling fertilizer consumption is around 47%, which fertilizer consumption is around 16%, rape can get high yields, rapeseed quality can reach the best level at the same time.2. The optimum application rate of biogas slurry taking the integrated soil quality and safety into accountBiogas slurry contains abundant nutritional elements, plowing the soil can not only supply of the essential elements for crop production, at the same time can improve soil quality, soil fertility, but excessive Biogas slurry membership had a negative impact, so control Biogas slurry seems has a vital role on soil quality.Through three years of applying Biogas slurry and water control compared to the conventional application of fertilizer to grow canola, fertilization of chemical fertilizer to cause a decline in soil pH, soil acidification harden and soil fertility decline, as well as the risk of heavy metal pollution. When applying control Biogas slurry content in 90000-132500 kg·hm-2 range, can effectively improve and maintain soil fertility, normal for crops need to grow;When applying Biogas slurry content in 90000-132500 kg-hm"2, within the scope of soil ion exchange best level; When applying Biogas slurry content in 101250-149500 kg·hm-2, within the scope of soil mineral elements with optimal state;When control Biogas slurry intake in 22500-132500 kg·hm-2 range, can make the soil heavy metal content in lower level. And through the safety assessment of soil heavy metal, the size of the single factor pollution index of heavy metals with the increase of applying Biogas slurry content, with its value rise, in ROM the comprehensive pollution index also showed a trend of the same, of which the largest contribution to the heavy metal Cd, so control exogenous Cd content, can very good reduce P heald value, causing soil pollution can reduce the risk and achieve the goal of sustainable production.Above all, should not only keep the rape high yield and high quality, and improve soil quality and reduce the risk of soil heavy metal pollution, applying should be controlled Biogas slurry content in the range of 101250-132500 kg·hm-2 range.