长期施肥对农田土壤肥力及重金属化学行为的影响

发布时间：2018-03-20 19:11

本文选题：长期施肥试验　切入点：肥力质量　出处：《湖南师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：农业生态系统长期定位实验(LTAEs)是指持续时间20年以上且具有有一定规模,用于研究农业过程的农作物产量、养分循环及环境效应的田间试验,能为农业可持续发展的生物学、生物地球化学和农业环境评价提供有价值的信息。本研究以农业部望城红壤性水稻土生态环境重点野外科学观测试验站和中国农科院祁阳红壤试验站为平台,研究了不同施肥条件和土地耕作方式土壤肥力质量的演变规律以及重金属污染状况、有效态和形态分配规律。主要研究结果如下：长期施肥对土壤理化性质的影响研究结果表明：长期施化肥可能导致土壤酸化,尤其是施氮肥,是导致土壤酸化的主要原因。红壤稻田施用稻草及猪粪都在一定程度上降低了土壤pH,红壤旱地施猪粪则有效地提高了土壤pH；长期施用有机肥能有效提高土壤有机质含量以及CEC。长期施肥对土壤养分影响的结果表明：施氮肥、有机肥或有机无机配施均能显著提高土壤全氮与碱解氮含量。施磷肥和有机肥能有效提高土壤磷素含量,且红壤旱地施有机肥土壤速效磷含量高于单施化肥；长期施钾肥,对土壤全钾影响不大,但施钾肥、有机肥或有机无机配施,均能显著提高土壤速效钾含量。长期施肥对土壤重金属化学行为的研究结果表明：望城红壤稻田各施肥处理土壤重金属Cd均超过国家土壤环境质量二级标准,其中施用猪粪处理Cd含量超过国家土壤环境质量三级标准。祁阳红壤早地除NP与NK处理外,土壤Cd均已超过国家土壤环境质量二级标准,其中施猪粪处理超过三级标准,Cu含量超过国家土壤环境质量二级标准,Zn有一定的积累,说明施猪粪是导致农田重金属积累的一个重要因素。长期施肥土壤重金属主要形态为残渣态,施猪粪对土壤重金属形态分配有显著影响：与施NPK相比,施猪粪显著提高土壤Cd积累,且以残渣态为主,可还原态次之,弱酸提取态与可氧化态增幅不明显；而施用猪粪使得其带入土壤中的Cu则主要转化为可还原态与可氧化态；对Zn元素而言,施猪粪对可氧化态含量增长作用不明显,引入的Zn主要转化为了其它几种形态。望城红壤稻田施有机肥能提高土壤Cu有效态含量,但对Cd及Pb有效态含量影响不大。祁阳红壤旱地施猪粪显著提高了Cd、Cu有效态含量,对Pb有效态含量影响不大。尽管施猪粪在一定程度上提高了土壤重金属全量以及有效态含量,然而却降低了土壤Cd和Pb的活化率,这可能是由于镉、铅与有机质螯合形成的有机无机复合体溶解度降低,所以,尽管绝对量提高,相对有效性却降低了。而施猪粪则能提高Cu活化率,可能是由于Cu容易与小分子有机酸结合,形成的复合体溶解度相对较高。通过逐步回归分析可知,不同重金属元素有效态含量影响的主要因素有所不同。Cu有效态含量主要受到Cu全量及CEC影响；Cd有效态含量主要受Cd全量及pH的影响；Zn有效态含量与CEC呈正相关关系；而Pb有效态含量则与有机质含量及pH呈负相关。
[Abstract]:Long term agricultural ecosystem experiment (LTAEs) refers to the duration of more than 20 years and has a certain scale, for the study of agricultural crop production process, field test of nutrient cycling and environmental effects, for biological agricultural sustainable development, provide valuable information on biogeochemical and agricultural environmental assessment. The research on Agriculture Department of Wangcheng red paddy soil ecological environment key field scientific observation station and Qiyang Academy of Agricultural Sciences Chinese red soil experimental station platform, the evolution law of the different conditions of fertilization and farming land soil fertility quality and heavy metal pollution, effective state and shape distribution. The main results are as follows: To study the influence of long-term fertilization on soil chemical properties indicate that long-term fertilization may lead to soil acidification, especially Shi Danfei, is the leading cause of raw soil acidification Because rice straw and pig manure application. To a certain extent, decreased soil pH, pig manure, upland red soil can effectively improve soil pH; long term application of organic manure can effectively improve the effect of soil organic matter content and CEC. of long term fertilization on soil nutrients showed that nitrogen fertilizer, organic fertilizer or organic inorganic fertilizer could significantly increase the soil total nitrogen and alkali hydrolyzable nitrogen. Nitrogen fertilizer and organic fertilizer could improve soil phosphorus content, organic fertilizer and upland soil available phosphorus content is higher than the chemical fertilizer; long-term Shi Jiafei effect on soil total potassium is not big, but the application of potassium fertilizer, organic fertilizer or inorganic fertilizer organic fertilizer were can significantly improve the content of available potassium in soil. Long term fertilization on soil chemical behavior of heavy metals. The results showed that: Wangcheng red paddy soil heavy metal Cd in all treatments are more than two national standards of soil environment quality The application of pig manure treatment, Cd content of more than three national standards of soil environment quality in Qiyang province. The earliest except NP and NK treatment, soil Cd has more than two national standards of soil environment quality, the pig manure processing more than three standard Cu content than the national soil environmental quality standard level two, Zn has a certain the accumulation of that pig manure is an important factor leading to the accumulation of heavy metals in farmland. The main forms of long-term fertilization for soil heavy metal residue, pig manure had significant effect on the speciation distribution of heavy metals in soil: compared with NPK fertilizer, pig manure increased soil Cd accumulation, and the residual iiifraction reducible second. Acid extractable state and oxidation state was not obvious; and the pig manure into soil Cu was mainly transformed into reducible and oxidizable elements; on Zn, pig manure on oxidizable content increase With the introduction of Zn is not obvious, mainly converted to several other forms. Wangcheng red paddy soil organic fertilizer could improve soil available Cu content, but had little effect on Cd and Pb. The effective content of Qiyang red soil upland pig manure significantly increased Cd, Cu of available content, available Pb content has little effect. Although pig manure increased the soil heavy metal total and available content to a certain extent, but it lowers the activation rate of soil Cd and Pb, which may be due to cadmium, organic and inorganic compound decreased, the solubility of lead and organic chelate forming so as to improve the absolute quantity, relative efficiency is decreased. Pig manure can improve the activation ratio of Cu, probably due to Cu easily with small molecular organic acids with relatively high solubility. The complex formed by stepwise regression analysis shows that the effect of available content mainly due to different heavy metals. The content of available.Cu is mainly affected by total Cu and CEC. The effective content of Cd is mainly affected by total Cd and pH, Zn effective state is positively correlated with CEC, while Pb effective state is negatively correlated with organic matter content and pH.

【学位授予单位】：湖南师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S158;X53

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