追施猪粪沼液对菜地氨挥发的影响

摘要

氨挥发是肥料氮素损失的主要途径之一.以厌氧发酵后的猪粪沼液为研究对象,通过蔬菜大棚小区试验,分析其作为追肥表施于冬季菜地(水芹(Oenanthe clecumbens L.)和扬花萝卜(Raphanus sativus L.Var.Radiculus pets.)；追施氮量分别为72 kg hm-2和54 kg hm-2)及夏季菜地(小白菜(Brassica chinensis L.)和大叶茼蒿(Chrysanthemum carinatum Schousb.)；追施氮量分别为42 kg hm-2和63 kg hm-2)后的氨排放特征及其影响因子.研究结果表明:(1)施用猪粪沼液后菜地氨挥发激增,沼液中氮素以氨挥发形态损失较快,通常发生在施入后48 h内；(2)冬季芹菜地和萝卜地施用沼液后的累积氨排放量分别为8.68 kghm-2和9.90 kg hm-2,显著高于化肥处理(4.06 kg hm-2和5.59 kg hm-2)；而夏季白菜地和茼蒿地则分别为10.40kg hm-2和11.61 kg hm-2,与化肥处理间差异不显著(9.81 kg hm-2和10.09 kg hm-2)；(3)冬季菜地施用沼液后氨挥发损失率分别达到11.7％和17.7％,显著低于夏季菜地(23.3％和26.8％)；(4)0 ～10 cm土层土壤温度、水分含量、可溶性有机碳含量、氮素水平及形态、微生物生物量及活性,均与菜地氨挥发有较高的关联度.沼液作为追肥施入农田后会因其自身氨挥发和激发效应而使氨排放增加,在施用过程中应特别注意温度的影响,同时应选择合适的施用方式.%Ammonia ( NH3) volatilization is a major pathway for gaseous nitrogen loss from fields applied with manure. To explore effects of topdressing of bio-digested manure slurry on ammonia volatilization, a field experiment was carried out in a vegetable greenhouse, applying bio-digested pig manure slurry ( DPS) on winter vegetable, cress ( Oenanthe clecumbens L. ) and radish ( Raphanus sativus L. Var. Radiculus pers. ) , and summer vegetable, pak choi ( Brassica chinensis L. ) and crown daisy ( Chrysanthemum carinatum Schousb. ). The topdressing rates of nitrogen were 72 kg hm ~ , 54 kg hm-2 , 42 kg hm-2 and 63 kg hm-2 , respectively, during the growing periods of vegetables. Results showed that (1 ) topdressing of DPS led to explosion of ammonia volatilization within 48 h; (2 ) the accumulative ammonia release of the growing season reached 8. 68 kg hm-2 and 9. 90 kg hm2 in cress and radish fields, respectively, which were significantly higher than those in the plots topdressing with chemical fertilizer ( CF) (4. 06 kg hm-2 and 5. 59 kg hm-2) ; however, in the pak choi and crown daisy fields, the value was 10. 40 kg hm -2 and 11. 61 kg hm-2, respectively, which were not so significantly higher than those in the plots topdressing with CF (9. 81 kg hm-2 and 10. 09 kg hm-2) ; (3) ammonia volatilization contributed 11. 7% and 17. 7% to the total N loss, respectively in the cress and radish plots topdressing with DPS in winter, and 23. 3% and 26. 8% in the pak choi and crown daisy plots in summer. The former was significantly lower than the latter; (4) temperature, water content, content of soluble organic carbon, form and concentration of nitrogen , biomass and activity of microbes in the surface soil at 0 ~ 10 cm depth were found to be the main contributors to ammonia volatilization. Application of bio-digested manure slurry in the vegetable field increased nitrogen loss through ammonia volatilization from DPS per se and its stimulative effect on decomposition of soil organic nitrogen. It is, therefore, essential to pay adequate attention to effects of temperature and application method in using bio-digested manure slurry as a soil amendment.