水稻田对猪粪的最大消纳能力研究

为最大限度地利用土地处理猪粪,减少养殖废弃物的排放和化肥的使用,采用大田试验方法,研究亚热带地区水稻田对猪粪的最大消纳能力.对水稻田施以4组不同水平猪粪处理——MNK1(猪粪7454kg/hm2、尿素55kg/hm2、钾肥36kg/hm2)、MNK2(猪粪14911kg/hm2、尿素110kg/hm2、钾肥71kg/hm2)、MNK3(猪粪19381kg/hm2、尿素143kg/hm2、钾肥92kg/hm2)和MNK4(猪粪23854kg/hm2、尿素176kg/hm2、钾肥113kg/hm2),检测施粪过程中降雨径流ρ(COD_Cr)、ρ(TN)、ρ(TP)、ρ(NH₄+-N)等的变化规律,结合水稻产量和各组施肥方式下土壤养分的累积,分析了亚热带地区水稻种植过程猪粪的最佳使用量和土壤承载力. 结果表明:①猪粪增施60%,则每hm2水稻增产180kg. ②MNK2处理的稻田土壤实际产生径流中的TN、TP流失量较MNK3处理分别少32%、39%；MNK2处理稻田土壤的w(TN)、w(TP)、w(TK)比MNK3处理分别减少9%、17%、26%；与全部施入化肥相比,水稻按MNK2水平进行施肥能减少氮、磷流失量6%、13%左右. 在保证经济效益和生态环境效益的同时,单季水稻田最大能消纳猪粪14911kg/hm2,每hm2水稻产量保持在6193kg水平上. 

Determination on Maximum Capacity of Pig-Manure Fertilization for the Rice Paddy in Subtropical Areas

The maximum capacity of pig-manure fertilization for the rice paddy in subtropical areas were determined, in order to understand the best way of pig-manure treatments by land. The purposes of treatments were to reduce the livestock waste emission, and to reduce the usage of chemical fertilizer, for general purpose of preventing from environmental pollution caused by improperly application of the pig-manure and chemical fertilizer. The most suitable amount of pig-manure fertilization and the land carrying capacity of pig-manure for the rice paddy in subtropical regions were revealed by experiment through different types of pig-manure fertilization strategies, which include the MNK1level that 7,4kg/hm2of pig-manure, 55kg/hm2of urea and 36kg/hm2of potash were fertilized; the MNK2level that 14,1kg/hm2of pig-manure, 110kg/hm2of urea and 71kg/hm2of potash were fertilized; the MNK3level that 19,1kg/hm2of pig-manure, 143kg/hm2of urea and 92kg/hm2of potash were fertilized; and the MNK4level that 23,4kg/hm2of pig-manure, 176kg/hm2 of urea and 113kg/hm2potash were fertilized. This study was carried out by complementing with the measured concentrations of COD_Cr, TN, TP, and NH₄+-N in the rainfall-runoff, the rice production and the accumulation nutrients in rice paddy of each pig-manure fertilization strategy. The results showed that the rice production could be increased by 180kg/hm2when the pig-manure fertilization increased by 60%. Compared with the MNK3treatments, the MNK2treatments reduced the loss of TN and TP by 32% and 39%, respectively. While the contents of TN、TP、TK in paddy soil was reduced by 9%,17% and 26%, respectively for the MNK2treatments, when compared with the MNK3treatments. The total loss of nitrogen and phosphorus in the MNK2treatments could be reduced by 6% and 13%, respectively, if compared with the chemical fertilizer. It is then estimated that on the base of ensuring ecological and economic benefits, the maximum capacity of pig-manure fertilization for the rice paddy was 14,1kg/hm2for a single production season. It can be concluded that each hectare could carry 45.38pigs per year and the rice yield can be maintained at the level of 6193kg/hm2per season for the MNK2fertilization strategy.