知识与财富的链接
为探讨餐厨垃圾堆肥对南方城郊菜田土壤氮素供应水平、叶菜类蔬菜产量及土壤残留和氮肥利用率的影响。以不施氮肥为对照(CK),在等氮量条件下,设置了传统化肥(NPK)、传统化肥+鸡粪(NPK+M)、餐厨好氧堆肥+化肥(NPK+FWA)、餐厨厌氧沼渣+化肥(NPK+FWD)4个处理,测定叶菜类蔬菜整个生育周期的土壤无机氮动态、产量、收获后剖面土壤氮素残留及表观氮素损失的变化。多茬试验结果表明:底肥施用后一周左右,NPK处理整体土壤无机氮供应水平高于NPK+M、NPK+FWA和NPK+FWD处理;追施氮肥后NPK+FWA处理土壤无机氮供应水平处于NPK和NPK+M两个处理之间,而NPK+FWD处理土壤无机氮略低于NPK和NPK+M处理;从总产量来看,NPK、NPK+M、NPK+FWA和NPK+FWD处理间无显著差异;而随着试验进行,与NPK+FWA和NPK+FWD处理相比,NPK和NPK+M处理产量明显增产20.1%～36.7%和17.8%～26.4%。从剖面土壤无机氮含量来看,餐厨垃圾堆肥部分替代化肥处理相比传统单施化肥和化肥配施鸡粪处理能够明显降低收获后表层土壤无机氮残留;从前四茬蔬菜总表观氮素损失来看,较高的氮肥投入带来了895.8～1041.2 kg/hm2的表观氮素损失量,各处理间无显著性差异;较高的氮肥投入及表观氮素损失导致小白菜季和空心菜季各处理当季氮肥利用效率分别仅有9.9%～16.7%和27.6%～37.6%。综上分析,在等氮量条件下,相比传统单施化肥和传统化肥配施鸡粪,餐厨垃圾堆肥氮替代30%化肥氮具有更好地协调土壤氮素供应和蔬菜作物吸收的作用,随着试验进行,餐厨垃圾堆肥部分替代化肥处理表现出增产趋势。但南方多雨地区餐厨垃圾堆肥还田具有较大的氮素损失风险,当季氮肥利用率偏低,今后需加强餐厨垃圾堆肥还田对土壤氮素综合损失的影响机制研究,并探索针对性的减排措施,为餐厨垃圾堆肥安全高效利用提供科学指导。
The aims were to investigate the effects of kitchen waste compost on soil nitrogen(N)supply level,the yield of leaf vegetable,residual N in soil profile and N use efficiency(NUE)in peri-urban vegetable field.Treatment without N-fertilizer was used as control(CK).Under the condition of equal N,four treatments including the conventional chemical fertilizer(NPK),the conventional chemical fertilizer with Chicken manure(NPK+M),aerobic kitchen waste compost with chemical fertilizer(NPK+FWA),and kitchen waste biogas residue with chemical fertilizer(NPK+FWD)were set up.The soil inorganic N dynamics in the whole leaf-vegetable season,the yield of vegetable,soil N residual in the profile and the apparent N losses were determined.The results of several vegetable seasons showed that:the overall soil inorganic N supply level of treatment NPK was higher than that of treatments NPK+M,NPK+FWA and NPK+FWD about a week after application of basal N fertilizer;After N topdressing,the soil inorganic nitrogen supply level of NPK+FWA was between NPK and NPK+M,while the soil inorganic nitrogen supply level of NPK+FWD was slightly lower than that of NPK and NPK+M.The four seasons total vegetable yields showed no significant difference among the NPK,NPK+M,NPK+FWA and NPK+FWD treatments.Nevertheless,with the experiment going on,NPK+FWA and NPK+FWD treatments obviously increased yield by 20.1%～36.7% and 17.8%～26.4%,respectively,in comparison to NPK and NPK+M treatments.In terms of the soil profile inorganic N,the partial replacement of chemical fertilizer by food waste composts significantly reduced the residual inorganic N in the surface soil after harvest compared with the traditional single application of chemical fertilizer and chemical fertilizer combined with chicken manure.The higher N input result in 895.8～1041.2 kg/hm2 apparent N loss in four vegetable seasons,and there was no significant difference among different treatments.The NUE of Pakchoi and Swamp cabbages in different treatments were only 9.9%～16.7% and 27.6%～37.6%,respectively,under the integrated effect of high N input and large apparent N loss.Based on the above analysis,under the equal amount of N,food waste compost N replacing 30% chemical N fertilizer has better role on coordinating soil inorganic N supply and vegetable N absorb,compared with the traditional single chemical fertilizer and chemical fertilizer with chicken manure,hence,food waste composts partly replace chemical fertilizer treatment showed an increasing trend with the experiment going on.Nevertheless,returning food waste composts to the field in rainy areas of southern China has a great risk of N loss and low NUE.Therefore,it is necessary to strengthen the study on the impact mechanism of returning food waste compost to the field on the integrated soil N loss and explore targeted emission reduction measures in future studies,so as to provide scientific guidance for safe and efficient utilization of food waste composts.
