不同外源添加物质对土壤氮磷素淋溶特征的影响

发布时间：2018-04-28 23:17

本文选题：土壤氮磷 + 淋溶　；参考：《西北农林科技大学》2017年硕士论文

【摘要】：氮磷流失是造成农业面源污染的主要原因,其中淋溶流失已成为不可忽视源,因此对氮磷在土壤中的淋溶流失研究具有重要意义。本文选取陕西省周至县竹峪乡俞家河农田土壤,采用室内模拟装置淋溶土柱的方法,探究了四种外源添加物质(土壤调理剂、砒砂岩、秸秆、生物炭)对土壤氮磷素淋溶特征的影响。并定期在流经该地区的俞家河设置10个不同断面取水样,测定总磷(TP)、总氮(TN)、总溶解性磷(TDP)、溶解性反应磷(DRP)、颗粒磷(PP)和溶解性有机磷(DOP),分析河水氮磷浓度变化及影响因素。论文主要得出以下结论:(1)生物炭可以增加淋溶液中PP、DPR和DOP的浓度,进而增加TP的浓度(变化范围0.68~2.86 mg/l)。随着生物炭(2%、4%、8%)施入比例的增大,淋溶液各形态磷和土壤中速效磷(Olsen-P)、可溶性磷(CaCl2-P)含量显著性增大,其中Olsen-P含量分别增加了141%、290%、382%,生物炭显著地提高了土壤中磷素的淋溶能力;秸秆增加淋溶液中DOP和PP浓度,进而增加TP的含量,同时DRP含量降低了50%,在TP中所占的比例仅为4.7%。秸秆减少淋溶液和土壤中有效磷含量,并阻止土壤中CaCl2-P向下层移动,减少磷素对环境的风险;(2)4%、8%的生物炭施用量降低了土壤氮素淋失分别为30%和20.7%,2%的生物炭施用量却增加了土壤氮素淋失量为5.9%,同时生物炭(2%、4%、8%)降低土壤中碱解氮含量,对氮素起到抑制作用。秸秆的施入降低土壤氮素淋失为9.7%,并使碱解氮含量增加59.1%,土壤中总氮和碱解氮含量主要集中在0-10 cm,秸秆显著地降低抑制氮素淋溶,并提高表层土壤肥力。砒砂岩对土壤中氮素的淋失起到抑制作用,短时间内减少了土壤中碱解氮含量。(3)俞家河河水TP、PP、TDP、TN浓度的变化具有季节性,4~9月作物生长期河水TP浓度都高于藻类发生的临界值(0.02 mg/l)。PP占TP的67.7%,是河水磷素主要形态,DRP和DOP含量较低,取决于河水本身,其中DOP浓度在7、8月较高,与河水温度有关。河水TN浓度的变化范围为1.6~14.0 mg/l,各月份其平均值为5.8 mg/l,均超过临界值(2 mg/l)。过量的施肥是河水中氮磷含量的主要来源,降雨和施肥是导致河水面源污染的主要原因。俞家河河水氮素污染更为严重,生物炭能降低氮素淋失,但确定其施入量时应综合考虑对磷素的促进作用。秸秆抑制氮素淋失的同时能降低磷素对环境的风险。砒砂岩和土壤调理剂对环境的作用不显著。
[Abstract]:Nitrogen and phosphorus loss is the main cause of agricultural non-point source pollution, among which leaching loss has become a source that can not be ignored, so the study of nitrogen and phosphorus leaching in soil is of great significance. In this paper, the soil of Yujiahe farmland in Zhuyuxiang, Zhouzhi County, Shaanxi Province was selected, and four kinds of exogenous substances (soil conditioning agent, arsenopyst, straw) were studied by means of indoor simulation device leaching soil column. Effects of biochar) on the leaching characteristics of nitrogen and phosphorus in soil. Ten water samples from different sections of Yujiahe River flowing through the area were set up on a regular basis to determine total phosphorus (TP), total nitrogen (TNN), total dissolved phosphorus (TDP), dissolved reactive phosphorus (DRP), particulate phosphorus (PPN) and dissolved organic phosphorus (DPP). The changes of nitrogen and phosphorus concentrations in river water and their influencing factors were analyzed. The main conclusions are as follows: (1) Biochar can increase the concentration of PPP-DPR and DOP in leaching solution, and then increase the concentration of TP (range 0.68 ~ 2.86 mg / L ~ (-1)). With the increase of the application rate of biochar, the contents of various forms of phosphorus in leaching solution and Olsen-Pn in soil, soluble phosphorus CaCl2-P) increased significantly, and the content of Olsen-P increased by 141 ~ 290 ~ (382), respectively. Biochar significantly improved the leaching ability of phosphorus in soil. Straw increased the concentration of DOP and PP in leaching solution, and then increased the content of TP. Meanwhile, the content of DRP decreased by 50%, and the proportion in TP was only 4.7%. Straw reduced the content of available phosphorus in leaching solution and soil, and prevented CaCl2-P from moving down in soil. To reduce the risk of phosphorus to the environment, to reduce the amount of biochar applied by 8%, to reduce the nitrogen leaching loss of soil by 30% and 20.7%, respectively, but to increase the amount of soil nitrogen leaching by 5.9g, and to decrease the content of alkali-hydrolyzed nitrogen in the soil by the addition of biochar. It has an inhibitory effect on nitrogen. The application of straw reduced the leaching loss of nitrogen to 9.7%, and increased the content of alkaline hydrolyzed nitrogen by 59.1%. The content of total nitrogen and alkali-hydrolyzed nitrogen in the soil was mainly 0-10 cm. The straw significantly decreased the inhibition of nitrogen leaching and improved the fertility of surface soil. Arsenic sandstone can inhibit the leaching of nitrogen in soil. In a short period of time, the content of alkali-hydrolyzed nitrogen in soil was reduced.) the change of TP concentration in the river water of Yujiahe River shows that the TP concentration in the river water during the growing period from April to September is higher than 67.7% of the critical value of algae, which is the main form of phosphorus in river water. The contents of DRP and DOP were low, Depending on the river itself, DOP concentrations are higher in July and August, depending on the river's temperature. The variation range of TN concentration in river water is 1.6 ~ 14.0 mg / l, and its average value is 5.8 mg / L in each month, which is above the critical value of 2 mg / L ~ (-1). Excessive fertilization is the main source of nitrogen and phosphorus content in river water, and rainfall and fertilization are the main causes of water non-point source pollution. The nitrogen pollution in Yujiahe River is more serious, and biochar can reduce the nitrogen leaching loss, but the promotion of phosphorus should be considered comprehensively when determining the amount of nitrogen applied in Yujiahe River. Straw can reduce the environmental risk of phosphorus while inhibiting nitrogen leaching. The effect of soft rock and soil conditioner on environment is not significant.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S158

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