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Alleviation of Soil Compaction by Brassica Cover Crops

dc.contributor.advisorWeil, Ray Ren_US
dc.contributor.authorChen, Guihuaen_US
dc.date.accessioned2009-10-06T05:54:09Z
dc.date.available2009-10-06T05:54:09Z
dc.date.issued2009en_US
dc.identifier.urihttp://hdl.handle.net/1903/9517
dc.description.abstractSoil compaction is a worldwide problem in modern agriculture associated with overuse of heavy machinery and intensification of cropping systems. Though tillage is traditionally used to alleviate compaction effect, increasing concerns about environmental impacts of tillage have led to interest in conservational tillage systems and incorporation of cover crops into crop rotations. Previous study showed soybean (Glycine Max L.) roots grew through a plowpan soil using channels left by canola (Brassica napus) cover crop roots, a process termed "biodrilling" to alleviate compaction effect. However, this study did not provide any quantitative data to support the observational conclusion. We studied "biodrilling" abilities of three cover crops and the effects of "biodrilling" on corn (Zea mays)/soybean growth by conducting three experiments. The first two experiments included three surface horizon compaction treatments (high, medium and no compaction), four cover crops [FR (forage radish: Raphanus sativus var. longipinnatus, cultivar `Daikon') and rape (rapeseed: Brassica napus, cultivar `Essex') (tap-rooted species in the Brassica family), rye (cereal rye: Secale cereale L., cultivar `Wheeler') (fibrous-rooted species) and NC (no cover crop)] in Exp. 1, and three cover crops (FR, rape and NC) in Exp. 2. The third experiment was conducted on field with a legacy plowpan (subsoil compaction) using FR, rye and NC cover crops. Roots of FR were least inhibited by compaction, while rye roots were severely arrested by compaction. The order of "biodrilling" ability was FR > rape > rye. Soil bulk density, strength and least limiting water range were controlled by compaction treatments. Soil air permeability was greatly reduced by compaction. Air permeability was greater in rape/FR treatments than in rye/NC treatments under high/medium compaction. Corn/soybean root penetrations, subsoil water uptake in the compacted soils were enhanced by FR/rape treatments but not by rye/NC treatments. Compaction decreased corn yield only in Exp. 2 where soil sand fraction was greater. The yield of corn was greater in three cover crop treatments than in NC control. In terms of "biodrilling", Brassica cover crops (FR and rape) were more effective than rye cover crop, would alleviate effects of soil compaction on plant growth in no-till farming systems.en_US
dc.format.extent3411339 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.titleAlleviation of Soil Compaction by Brassica Cover Cropsen_US
dc.typeDissertationen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.contributor.departmentPlant Science and Landscape Architecture (PSLA)en_US
dc.subject.pqcontrolledAgriculture, Soil Scienceen_US
dc.subject.pqcontrolledAgriculture, Agronomyen_US
dc.subject.pquncontrolledBrassica cover cropen_US
dc.subject.pquncontrolledRoot Penetrationen_US
dc.subject.pquncontrolledSoil Compactionen_US
dc.subject.pquncontrolledSubsoilen_US
dc.subject.pquncontrolledWater uptakeen_US


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