The Effect Of Grass Intercropping And Biogas Fertilizer Application On Soil Environment And Fruit Quality In Citrus Orchard

This study took organic citrus orchard in Poyang Lake Ecological Economic Zone as test area. In order to investigate the effect of different grass intercropping on soil environment and fruit quality, selecting the better grass sward apply in citrus orchard in Poyang Lake Ecological Economic Zone; studied the effect of growth, yield and quality of citrus fruit with different dosage of biogas fertilizer, analysised the correlation of heavy metals between soil and fruit, and ascertained amount of biogas fertilizer safe standards. The main results were as follows:1. Compared with clean tillage, different grass intercropping increased the number of soil bacteria, fungi, actinomycetes microorganism; improved the activity of soil catalase, urease, invertase, phosphatase, among witch, intercropping Cichorium intybus L. and Perilla frutescens. were better than other treatments.2. Compared with clean tillage, different grass intercropping improved soil organic matter, total nitrogen, total phosphorus and total potassium content, which increased 4.40%~7.44%, 12.09%~35.16%, 9.09%~24.24%, 0.92%~7.72%, also Perilla frutescens. treatment which worked best for increasing soil organic matter content, improved up to 7.44%; Cichorium intybus L. and Perilla frutescens. treatments were better increased soil phosphorus and potassium content, the difference was significant.3. Compared with clean tillage, different grass intercropping improved the fruit soluble solids content 0.10%~0.74%, increased total soluble sugar content 0.05%~0.21%, and vitamin C content was improved 2.66~4.67mg/100 g, decreased titratable acidity content 0.02%~0.05%; compared with natural grass and clean tillage treatments, grass intercropping improved fruit quality, Cichorium intybus L. and Perilla frutescens treatments were better than other treatments, and the difference was significant.4. Application of biogas fertilizer promoted spring and autumn twig of citrus, also different amount of biogas fertilizer exhibited different growth effect, with increasing amount of biogas fertilizer, fruit yield increased first then decreased; application of biogas 48405kg/hm2 yield the best results, compared with organic manure and chemical fertilizer treatments, yield rate of 8.40% and 9.49%.5. Application of biogas fertilizer improved fruit quality, compared with organic manure and chemical fertilizer treatments, application of biogas 48405kg/hm2 was the best, vitamin C content was 24.27mg/100 g, and sugar acid ratio reached 14.59, also increased soluble solids content 0.40%, 0.73%, total soluble sugar content 0.24%, 0.33%, decreased titratable acidity content 0.04%, 0.05%.6. Application of biogas fertilizer two years, heavy metals Cu, Zn, Pb, Cr, Cd, As content were not exceedanced in soil and fruit, correlation analysis showed that heavy metals of Cu, Zn, Cr, Cd, the regression equation R2>0.90 between soil and fruit, Correlation curve fitting analysis available heavy metals Cu, Zn, Cr, Cd in soil to predict the content of heavy metals Cu, Zn, Cr, Cd in fruit.