不同有机氮替代部分无机氮对水稻产量及土壤微生物的影响

通过田间试验,探索不同有机氮肥替代部分无机氮对汉中盆地水稻产量及土壤微生物的影响,旨在探索该区水稻生产的氮肥减量技术。试验共设不施肥(CK)、无机氮肥(100%N)、沼渣有机肥替代20%无机氮(80%N+BRO)、微生物有机肥替代20%无机氮(80%N+BOF)、秸秆替代20%无机氮(80%N+SW)5个处理。采用稀释涂平板的方法测定水稻移栽前期、苗期、分蘖期、孕穗期和成熟期0～20 cm土层的土壤微生物数量,并测定水稻产量及构成要素。结果表明,80%N+BOF处理可显著增加水稻有效穗数和穗粒数,较CK和100%N水稻籽粒产量分别增加77.21%和2.72%;水稻整个生育期土壤细菌和真菌数量先降低再升高,放线菌先升高再降低;80%N+BRO处理可显著提高水稻各生育期细菌、放线菌和微生物总数量,在水稻苗期、分蘖期和孕穗期效果最显著;80%N+BOF处理可显著提高水稻各生育期B/F值、降低真菌数量,并减小微生物群落结构变化,在水稻孕穗期和成熟期效果最显著。80%N+BOF处理在水稻上应用效果较好,可显著提高产量构成要素、水稻籽粒产量及土壤微生物数量,且有利于改善土壤微生物结构,为适宜于汉中盆地稻田化学氮肥减量的有效措施。

Effects of Partial Replacement of Chemical Fertilizer by Organic Manure on Rice Yield and Soil Microorganisms in Hanzhong Basin

In order to explore the technology of reducing nitrogen fertilizer in rice production.Field experiments were conducted to investigate the effects of different organic nitrogen fertilizers on rice yield and soil microorganisms in Hanzhong basin. Five treatments were set up,including no fertilizer(CK),100% urea (100%N),replacing 20% inorganic nitrogen with biogas residue organic fertilizer (80%N+BRO),replacing 20% inorganic nitrogen with microbial organic fertilizer(80%N+BOF),replacing 20% inorganic nitrogen with straw(80%N+SW). The yield and yield components of rice under different treatments were determined. The number of soil microorganisms in 0-20 cm soil layer was determined by dilution method of plate counting at different stages,which included pre-transplantation,seedling stage,tillering stage,booting stage and maturity stage of rice. Fertilizer reduction combined with microbial bacterial fertilizer could significantly increase the number of effective panicles and grains per panicle in rice. Compared with control and conventional fertilization,rice grain yield increased by 77.21% and 2.72% respectively. During the whole growth period of rice,the number of soil bacteria and fungi decreased first,then increased,and actinomycetes increased first and then decreased. The total amount of bacteria,actinomycetes and microorganisms could significantly increased by application of biogas residue organic fertilizer and chemical fertilizer reduction,and the effect was most significant at seedling stage,tillering stage and booting stage of rice. Fertilizer reduction combined with microbial organic fertilizer could significantly increase the B/F value,reduce the number of fungi,and reduce the change of microbial community structure. The effect was most significant at booting and maturing stages of rice. Replacement of chemical fertilizer by microbial organic fertilizer on rice was better. It could significantly increase rice grain yield,yield components and soil microbial quantity,and improve soil microbial structure. It is suitable for fertilizer reduction in rice production in Hanzhong basin.