Effect Of The Continuous Application Of Biogas Slurry On Quality Of Oilseed Rapes And Soil Environment Under The Mode "Rice-Cole"

As a kind of high-quality and efficient biological organic fertilizer with fast-acting an d long-acting characteristic, biogas slurry could completely replace chemical fertilizers. It i s also the best fertilizer for the production of organic food. The biogas slurry contains resist ance of bioactive substances, includes amino-acids, proteins, humic acid, auxin, gibberellin , carbohydrates, B vitamins, antibiotics and plant growth hormone(indole acetic acid,butyri c acid), more than half of N/P/K in the raw material remains in the biogas slurry. Usage of biogas slurry in agriculture can effectively regulate the heat, water, gas, fertilizer in the soil . Meawhile, it may promote virtuous circle of soil ecological environment, provide nutrient s and good soil environment for crop growth. The advantages of biogas slurry applied in ag riculture embodies reduce kilograms of pesticide and chemical fertilizers, reduce productio n costs, increase agricultural income, increase the yield and quality of crops. Also, it could meet the pursuit of pollution-free, high-quality, nutrition security of food,which is useful f or improvement of people’s quality of life.This thesis adopted the field experiment, and fermented completely biogas slurry as the irrigation fertilizer,rape is tested crops, Studying effects of long-term locating fertilization on rapeseed yield and quality, soil environmental quality change under the "Rice-oil" rotation system.Using pure biogas slurry instead of conventional fertilizers irrigating rape,determining the best dosage of biogas slurry for rapeseed production, Researching bearing capacity and digestion capacity of the soil irrigating biogas slurry under the mode "Rice-oil".Thus to provide a theoretical basis for the apply of biogas slurry in the chengdu plain and the surrounding yellow brown loam areas. The results of this study were as follows:1. The optimum application range of biogas slurry considering improving the yield and quality of oil-seed rapeWithin the range of the experimental design, the biogas slurry was applied for two year in a row,according to the results:Appropriate amount of biogas slurry application can significantly improve grain yield of the rape,reduce the contents of rapeseed glucosinolate and erucic acid,increase the contents of protein,oleic acid and linoleic acid. With biogas slurry dosage increasing, the content of rapeseed NPK show a trend of "rise";the biogas slurry promote six kinds of mineral elements accumulation in rapeseed,such as the iron,manganese,copper,zinc,calcium,magnesium. Using single factor method and Nemerow index evaluation comprehensive pollution evaluation method for safety evaluation of rapeseed heavy metal under the various fertilization treatments,the evaluation results is "clean", What’s more, they are all in line with the corresponding limits of "Hygienic Standard for Oil seeds"and "Limit standards for food".When the biogas slurry application rate is controled in the range of 4269-8838kg/666.7m2,the contents of heavy metals of rapeseed stay at a low level. When the biogas slurry application rate is controled in the range of 8287-12239kg/666.7m2, rapeseed protein can obtain a higher concentration. When the biogas slurry application rate is controled in the range of 4269-9973kg/666.7m2, the contents of oil are high compared to other biogas slurry treatments. When the biogas slurry application rate is controled in the range of 6537-9973kg/666.7m2, rapeseed can obtain a higher content of oleic acid. When the biogas slurry application rate is in the range of 7254-12239kg/666.7m2, the contents of glucosinolate and erucic acid are significantly lower than other biogas slurry treatments. When the biogas slurry application rate is in the range of 7254-11106kg/666.7m2, the yield of rapeseed under biogas slurry treatments are all significantly higher than that of conventional chemical fertilizer treatment.Considering effects of biogas slurry irrigation rate on the yield and quality of rape, When the biogas slurry application rate is in the range of 7254-8838kg/666.7m2(6 to 9),the yield and quality of rape can achieve the best.2. The best biogas slurry dosage range for soil fertility and soil environment quality.Biogas slurry is a high-quality and efficient liquid organic fertilizer,its nutrients not only promote crop growth,but also improve soil fertility.The exerimental study shows that the biogas slurry position application for 2 years in a row, the soil pH,total nitrogen,available nitrogen,available potassium,CEC content are higher than the bottom of the soil value.Within the scope of the approopriate dosage of biogas slurry,trace element,enzyme activity and soil microorganism in the soil have also improved. Using single factor method and Nemerow index evaluation comprehensive pollution evaluation method for safety evaluation of soil heavy metal under the various fertilization treatments,fresh water treatment,conventional fertilizer treatment and the biogas slurry 3 to 6 treatments’soil pollution levels are from "light pollution" into "clean". In addition to soil Cd,the remaining soil heavy metals’Pi value are less than 1. When the biogas slurry application rate is in the range of 7254-9973kg/666.7m2(6 to10), biogas slurry handling soil nutrient treatment effects are better than conventional fertilizer treatment. When the biogas slurry application rate is in the range of 6537-9973kg/666.7m2(5 to 10),the contents of trace elements in the soil are maintained at an optimum level. When the biogas slurry application rate is in the range of 4269～8838kg/666.7m2(3 to 9),the contents of heavy metals in soil maintain at a low level.In summary, in the "rice-oil" crop rotation system,considering the fertility and environmental quality of the soil,we know that When the biogas slurry application rate was in the range of 7254～8838kg/666.7m2(3 to 9),the application of biogas slurry reflects the best of environmental benefits.In summary,comprehensive consideration of effects of the factors(include rape growth and development,the yield and quality of rape,soil fertility and soil quality)by biogas slurry application rate,we conclude that When the biogas slurry application rate was in the range of 7254～8838kg/666.7m2(3 to 9), the biogas slurry irrigating soil both to ensure the production of rapeseed and grain security, sustainable production of soil,at this time,the economic and environmental benefits of biogas slurry irrigation are to achieve the best balance.Rape is planted in the soil of the region,the largest digestion amount of biogas slurry is 8838 kg/666.7m2.