红壤地区草-牛-沼生态系统中养分循环利用的研究

在中度熟化的红壤岗地上采取种植黑麦草和玉米饲喂肉牛,牛粪尿沼气发酵后的沼肥与化肥配施养草的方式,并以单施化肥养草喂牛的方式为对照,进行2年试验研究草-牛-沼生态系统中的养分循环。结果表明,沼肥与化肥配施处理玉米植株的产量和养分积累量都高于单施化肥处理,而黑麦草产量和养分积累量都稍低于单施化肥处理,但由于配施沼肥可节省一半的化肥投入,其效益都很显著。牛对不同施肥处理同种饲草中养分的消化率差异不显著,牛粪尿对养分的回收率也差异不明显,但不同种或同种而收获期不同的饲草消化率和回收率都差异明显。牛粪尿经沼气发酵后回收的养分量可节约饲草生产中近一半的化肥投入。且沼肥施用后土壤肥力得以保护和改善,为后续的饲草生产提供了较好的土壤条件,从而有利于养分循环利用。

Nutrient cycling and utilization in a forage cultivation-cattle raising-biogas fermentation ecosystem in red soil regions

Rye grass and maize cultivated in mid-mellow hilly red soil were harvested to feed beef cattle. In the process of forage cultivation and cattle raising,two treatments were set,one of which was that forage was fertilized with chemical fertilizer only and was harvested to feed beef cattle(CK);another was that cattle feces and urine fermented in biogas pool was mixed with chemical fertilizer and the biogas-tank sludge,and applied to forage fields to grow animal feed. The results of two-year experiments show that the yield and nutrient accumulation of maize plants with the mixed application of biogas-tank sludge,are higher than those with chemical fertilizer only, but on the contrary,those of rye grass are lower. The application of mixed biogas-tank sludge can save chemical fertilizer by 1/2. There is little difference among cattle's digestion and recovery rate of nutrient of the same forage with different fertilization compositions, but there is significant difference among different varieties and different harvesting times of one variety. Most nutrients in the cattle's excrements can be recovered after biogas fermentation,saving about half of the input of the chemical fertilizer. The mixed application of biogas-tank sludge can maintain and improve the soil fertility,which provides better soil conditions for the sustainable production of forage.