【作者】 李茹；

【导师】 程滨； 焦晓燕；

【作者基本信息】 山西大学 ， 水土保持与荒漠化防治， 2017， 硕士

【摘要】 核桃是山西的一种特色农产品,种植面积达40万公顷。核桃青皮是核桃外部一层厚厚的绿色果皮,其主要成分有萘醌及其苷类、黄酮及其苷类、二芳基庚烷类、萜类、有机酸类等一系列化合物。核桃青皮具有化感作用,能够抑制土壤中氮硝化、减少N2O等氮氧化物的排放。此外,核桃青皮作为有机物质施入土壤可以提高土壤有机质含量。本文采用模拟土培试验比较了核桃青皮与双氰胺(DCD)和楝粉对氮的硝化作用的抑制效果,筛选出核桃青皮抑制氮硝化作用较适宜的用量,探讨了核桃青皮在酶学和微生物学上的硝化抑制机理,旨在为核桃青皮作为一种生物硝化抑制剂提供科学依据。试验结果如下:1核桃青皮施入土壤可以显著降低尿素在土壤转化过程中NO3--N的含量而增加NH4+-N含量。土壤中加入0.5 g/kg和1 g/kg核桃青皮,与对照相比NO3--N含量分别降低46.26%和57.89%;NH4+-N含量分别增加370.05%和406.46%。核桃青皮有抑制土壤中脲酶活性、提高土壤硝酸还原酶活性和亚硝酸还原酶活性的作用,不同青皮用量处理间差异显著,与对照相比脲酶活性分别降低9.04%和15.73%,硝酸还原酶活性分别增加20.30%和73.81%,亚硝酸还原酶活性分别增加12.37%和40.82%。核桃青皮用量为1 g/kg土时效果明显。2核桃青皮、DCD和楝粉都能抑制NH4+-N向NO3--N的氧化过程,降低尿素在土壤转化过程中NO3--N含量而增加NH4+-N含量,与对照相比NO3--N含量分别下降58.50%、66.92%和55.30%,NH4+-N含量分别升高428.57%、814.28%和289.10%。核桃青皮、DCD和楝粉均有抑制土壤中脲酶活性,提高土壤中硝酸还原酶活性和亚硝酸还原酶活性的作用,与对照相比脲酶活性分别降低2.83%、10.42%和8.34%,处理间差异不显著;硝酸还原酶活性分别增加25.79%、77.79%和17.07%,处理间差异显著;亚硝酸还原酶活性分别增加32.10%、53.91%和26.32%,处理间差异显著。抑制效果DCD>核桃青皮>楝粉。3核桃青皮、DCD和楝粉有抑制土壤中氨氧化菌、促进反硝化菌繁殖的作用。试验初期各处理间有显著性差异,作用效果DCD>核桃青皮>楝粉,与对照相比氨氧化菌分别降低93.15%,93.55%和91.71%,反硝化菌分别增加673.33%,1040.72%和464.44%;培养后期各处理差异不显著。更多还原

【Abstract】 Walnut is one of the characteristic agricultural product of Shanxi,and the planting area is 400,000 ha.A lot of walnut green husk were produced every year.Walnut green husk is a thick layer of green peel outside unripe walnut.Its main ingredient contains the naphthoquinone and its glycosides,flavonoids and glycosides,two aryl heptane,terpenoids,organic acids and a series of compounds.The allelopathy effects of walnut green husk can inhibit soil nitrification and reduce the N2 O emission of nitrogen oxides.In addition,walnut green husk can increase the contents of organic matter.In this paper,the inhibitory effect of walnut green husk,cyanide(DCD)and neem powder on the nitrification of nitrogen was studied by simulating soil culture test,the effects of them on nitrogen nitrification were compared,and the mechanism of walnut green husk in the enzymatic and microbiological inhibition mechanism were explored.It aimed to provide scientific basis for walnut green husk as a kind of biological nitrification inhibitor.The results showed that:1 Appling walnut green husk can significantly decrease the content of NO3--N and enhance the fixation of NH4+-N during the urea transformation process in soil.Compared with the control treatment,the content of NO3--N decreased by 46.26% and 57.89% and NH4+-N increased by 370.05% and406.46% when applying 0.5 g and 1 g walnut green husk per 1kg soil.Walnut green husk has the roles of inhibiting urease activity and improving nitrate reductase activity and nitrite reductase activity in soil.There were significant differences between the treatments.Compared with the control treatment,the urease activity decreased by 9.04% and 15.73%,and the nitrate reductase activity increased by 20.30% and 73.81%,and the nitrite reductase activity increased by 12.37% and 40.82%.The dose of 1 g walnut green husk per 1kg soil was perfect.2 Walnut green husk,DCD and neem powder inhibited the oxidation fromNH4+-N to NO3--N,decreased the content of NO3--N in soil,and enhanced the fixation of NH4+-N in the soil.Compared with the control treatment,the content of NO3--N decreased by 58.50%,66.92% and 55.30%,and the content of NH4+-N increased by 428.57%,814.28% and 289.10%.Walnut green husk,DCD and neem powder inhibited soil urease activity,improved soil nitrate reductase activity and nitrite reductase activity.Compared with the control treatment,the activities of urease decreased by 2.83%,10.42%and 8.34%,the activities of nitrate reductase increased by 25.79%,77.79%and 17.07%,and the activities of nitrite reductase were increased by 32.10%,53.91% and 26.32%.The inhibition effect is DCD> walnut green husk>neem powder.3 Walnut green husk,DCD and neem powder applied in soil significantly controlled the oxidation of ammonia growth in the soil and promoted the propagation of denitrifying bacteria.In the early of the experiment,there were significant differences between the treatments,the effect of DCD>walnut green husk>neem powder.Compared with the control treament,the number of ammonia-oxidizing bacteria decreased by 93.15%,93.55% and91.71%,and the denitrifying bacteria increased by 673.33%,1040.72% and464.44%.There were no significant differences in the treatments.更多还原