Short-term effects of graminaceous cover crops on autumn soil mineral nitrogen cycling in western Lower Fraser Valley soils |
Posted on:1999-04-11 | Degree:Ph.D | Type:Dissertation |
University:The University of British Columbia (Canada) | Candidate:Nafuma, Leonard Simiyu | Full Text:PDF |
GTID:1465390014969500 | Subject:Agronomy |
Abstract/Summary: | |
Proper cover crop management practices in autumn can minimize NO;Planting crops in August as compared to a month later increased biomass production by 56 to 135% and N uptake by 38 to 93% before winter leaching period. Large N uptake by cover crops that were planted in August was generally accompanied by significant reduction in soil mineral N (0-60 cm) from August to November.;August-planted spring species N at winter-kill was largely composed of the protein fraction (insoluble and soluble) which increased with N supply in autumn when the initial mineral N contents in 0-60 cm layer of soil were suboptimal (;Spring species can be included in winter cropping systems in western Lower Fraser Valley. Spring species that were planted in August and winter-killed in late autumn showed greater potential to retain the N accumulated before winter-kill compared to the cover crops that were planted a month later. August-planted spring species increased soil mineral N (by 40 to 76%) in the 0-60 cm layer in spring relative to fallow plots while September-planted crops had little effect. It appears, spring species can play a significant role in autumn mineral N conservation by accumulating large amounts of autumn soil mineral N before winter leaching period, retaining it in winter-killed residues until spring and releasing the N in plant available form through decomposition and mineralization. |
Keywords/Search Tags: | Autumn, Mineral, Crops, Cover, Spring, August |
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