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Phosphorus leaching as influenced by animal manure and catch crops

Liu, Jian (2013). Phosphorus leaching as influenced by animal manure and catch crops. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2013:55
ISBN 978-91-576-7848-5
eISBN 978-91-576-7849-2
[Doctoral thesis]

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Abstract

Leaching of phosphorus (P) constitutes an important part of P losses from Swedish agricultural soils. Phosphorus leaching is complex and is influenced by many factors, from source and mobilisation to transport pathways, as well as agricultural management practices. In order to design appropriate mitigation strategies to reduce P leaching, it is urgent to understand how different factors influence P leaching and to understand the methods for assessing P leaching.

This thesis investigated the influence of two management practices, application of animal manure and use of catch crops, on P leaching under Swedish conditions and devised corresponding mitigation strategies. In the case of manure application, lysimeters were used to study P leaching from topsoil as influenced by soil type, manure application method and long-term manure application. In addition, P leaching from a field associated with long-term manure application was simulated with the ICECREAM model to clarify the processes dominating P leaching. In the case of catch crops, uptake of P by potential species and leaching of P from them after freezing and thawing were examined in a greenhouse and in a topsoil lysimeter study.

Conclusions are: (1) Recent manure application to clay soils with macropore flow pathways generates a high risk of P leaching and thus such application of P during wet periods must be followed by incorporation of manure into the soil or avoided; (2) application of moderate rates of pig slurry to sandy soils with sufficient P sorption capacity does not increase the risk of P leaching, and P can be applied at a rate in balance with crop removal; (3) given the same P rate, pig slurry does not constitute a larger risk of P leaching than mineral P fertilisers; (4) descriptions of P sorption/desorption processes dominated by Fe and Al oxides must be included in P models such as ICECREAM; and (5) catch crops can become a source of P losses after exposure to freezing-thawing, which should be considered when using a catch crop.

In future, more research is needed to investigate mitigation strategies to minimise P leaching from clay soils, to select or modify catch crop species to be efficient for P, and to develop methods for accurately assessing risk of P leaching.

Authors/Creators:Liu, Jian
Title:Phosphorus leaching as influenced by animal manure and catch crops
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研究背景:氮磷等营养元素过量富积引起的水体富营养化是一个存在于全球多地区的、严重的环境问题。如美国的切萨皮克湾(Chesapeake Bay),北欧的波罗的海(Baltic Sea)和中国的太湖、巢湖和滇池等内陆湖以及沿海水域如渤海湾等近年来时有藻类大量暴发,对水体质量和渔业造成严重威胁。随着生产技术和污水治理技术的改进和成熟,来源于工业点源的氮磷排放量大大减少;相应地,农业和林业等面源污染在全部污染中所占的比例有所上升。在很多国家和地区,农业是地表水的主要氮磷污染源。磷素被公认为是内陆水域和类内陆水域(如波罗的海)富营养化的限制因素,因而近年来逐渐成为研究热点。在西方发达国家,自二战之后动物厩肥和无机肥料的大量施用导致大多数农田土壤存在磷素过量累积的问题。比如,土壤养分测定显示瑞典50%的农田具有较高或很高的磷素水平,进而存在磷素损失的风险。大多数发达国家和一些发展中国家已经意识到农田磷素损失所引发的水环境问题,并寻求解决办法,其中包括规范农业生产和进行农业补贴等。对此,美国和欧盟相应的学术和研究网络(如SERA-17,EU COST Action 869)分别提出了很多建议以减少磷素从农田系统中的流失。
土壤中磷素的流失是磷源、转化和运移等因素的综合结果,并最终在磷限制的水体中造成富营养化。流失类型包括通过地表径流与侵蚀损失和淋溶损失。以哪种类型为主主要由天气状况、地形和土壤特征决定。在瑞典,大多农业用地坡度都比较小,并且具有良好的天然或人工排水系统,因此,磷的淋溶是很重要的损失类型。在欧美包括瑞典,动物厩肥是农业生产中非常重要的磷源,也是农业向水体排放磷素的重要贡献者,引起了水质管理研究者的广泛关注。填闲作物是种植在两季主要作物之间的短期生长的作物。主要用于防止土壤侵蚀和减少土壤中氮素淋溶损失,但对磷素损失的效用还不清楚。相反,在北欧冬天存在冻融的情况下,作物储存在体内的磷可能会伴随由冻害引起的细胞破裂而释放出来,进而流失到水体。由于有政府的补贴,填闲作物在瑞典和丹麦广泛种植,因此,很有必要研究其在冻融条件下可能产生的负面环境效应。

研究目标:研究在瑞典农业中,动物厩肥的短期和长期施用以及填闲作物的种植如何影响土壤磷素的淋溶损失。在此基础上,制定相应的减少磷素损失的策略。

研究方法:在厩肥项目中,应用原状土柱渗漏法(lysimeter)研究了土壤类型、厩肥施用方法和长期厩肥施用对耕层土壤中磷素淋溶的影响。此外,应用ICECREAM模型对磷素从施用厩肥的大田中长期淋溶的结果进行了模拟,并以此确定控制磷素淋溶的关键过程。在填闲作物项目中,研究了8种作物在温室和大田条件下对磷素的吸收,并分别应用温室种植和原状土柱渗漏法研究了冻融条件下磷素的损失。

主要结论:
(1) 厩肥在具有大孔隙流的粘土上的近期施用会造成较大的磷素淋溶风险。通过把厩肥混入土壤,该风险可以降低,但不会完全消除。因此,在这种土壤条件下,特别是在雨季,厩肥应该被混入土壤或免施。
(2) 中量的厩肥在具有足够吸磷能力的沙土上的施用不会造成磷素淋溶风险。因此,厩肥可以施用到这样的土壤上,但施磷量要与作物移除量平衡。
(3) 在同样施磷量的情况下,猪液体厩肥不会比无机磷肥造成更高的磷素淋溶风险。
(4) 在很多土壤中,磷素的吸附/解吸过程是由铁铝氧化物控制的。这个过程应该被包括在磷素模拟模型中,比如本论文中用到的ICECREAM模型。
(5) 在冻融条件下,填闲作物会成为磷素损失源,可能增加磷素向水体的损失量。因此,在存在冻融的地区种植填闲作物时要考虑到这一点。

Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :2013
Volume:2013:55
Number of Pages:64
Papers/manuscripts:
NumberReferences
I.Liu, J., Aronsson, H., Ulén, B. & Bergström, L. (2012) Potential phosphorus leaching from sandy topsoils with different fertiliser histories before and after application of pig slurry. Soil Use and Management 28(4), 457-467.
II.Liu, J., Aronsson, H., Bergström, L. & Sharpley, A. (2012) Phosphorus leaching from loamy sand and clay loam topsoils after application of pig slurry. SpringerPlus 1: Paper 53 (10 pp) http://www.springerplus.com/content/1/1/53.
III.Liu, J., Aronsson, H., Blombäck, K., Persson, K. & Bergström, L. (2012) Long-term measurements and model simulations of phosphorus leaching from a manured sandy soil. Journal of Soil and Water Conservation 67(2), 101-110.
IV.Liu, J., Khalaf, R., Ulén, B. & Bergkvist, G. (2013) Potential phosphorus release from catch crop shoots and roots after freezing-thawing. Plant and Soil DOI 10.1007/s11104-013-1716-y (in press).
Place of Publication:Uppsala
Publisher:Dept. of Soil and Environment, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-7848-5
ISBN for electronic version:978-91-576-7849-2
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P30 Soil science and management
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 105 Earth and Related Environmental Sciences > Environmental Sciences (social aspects to be 507)
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Soil Science
Agrovoc terms:phosphorus, leaching, catch crops, organic fertilizers, fertilizer application, lysimeters, sorption, desorption, models
Keywords:catch crop, degree of phosphorus saturation, freezing-thawing, ICECREAM model, lysimeter, manure application, phosphorus leaching, soil type, sorption-desorption processes
URN:NBN:urn:nbn:se:slu:epsilon-e-1578
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-1578
ID Code:10739
Department:(NL, NJ) > Dept. of Soil and Environment
(S) > Dept. of Soil and Environment
Deposited By: Jian Liu
Deposited On:15 Aug 2013 08:21
Metadata Last Modified:13 Dec 2014 21:00

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