The effects of cover crops on phosphorus cycling in agricultural soils of California

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Abstract/Contents

Abstract
Phosphorus (P) limits agricultural productivity because most soil P is found in pools of low plant-availability and external inputs that are used to increase plant-available P are only partially recovered in crops, resulting in low P use efficiency (PUE). Cover crops could reduce external P input requirements, increase PUE and stimulate soil P cycling by mobilizing soil P and by retaining soil P via plant uptake, especially in low-input agricultural systems. This dissertation seeks to determine if cover crops have similar effects on soil P cycling in intensive agricultural systems with relatively high soil P, using two long-term experiments in California, greenhouse experiments and nutrient budgets. In both field and laboratory conditions, legume cover crops had a greater potential to mobilize soil P than other cover crops, although in practice they did not mobilize soil P. In contrast, cereals had the strongest effect on soil P availability and P cycling by taking up more soil P than other cover crops. Regardless of cover crop type, P taken up in cover crop biomass was recycled rapidly in these systems: cover crop residues and mineral fertilizer contributed similarly to soil pools and wheat P uptake, with a greater contribution at lower soil P availability. However, cover crops had relatively small effects on long-term soil P dynamics relative to compost addition that was the main factor driving differences in P budgets computed at the farm-scale. Overall, cover crops have the potential to affect soil P cycling in these systems with relatively high soil P, although to a lesser degree than do composts.

Description

Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2015
Issuance monographic
Language English

Creators/Contributors

Associated with Maltais-Landry, Gabriel
Associated with Stanford University, Department of Biology.
Primary advisor Vitousek, Peter Morrison
Thesis advisor Vitousek, Peter Morrison
Thesis advisor Fendorf, Scott
Thesis advisor Field, Christopher B
Thesis advisor Scow, Kate M
Advisor Fendorf, Scott
Advisor Field, Christopher B
Advisor Scow, Kate M

Subjects

Genre Theses

Bibliographic information

Statement of responsibility Gabriel Maltais-Landry.
Note Submitted to the Department of Biology.
Thesis Thesis (Ph.D.)--Stanford University, 2015.
Location electronic resource

Access conditions

Copyright
© 2015 by Gabriel Maltais-Landry
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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