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Repeated use of green-manure catch crops in organic cereal production - grain yields and nitrogen supply

Løes, Anne-Kristin; Henriksen, Trond Maukon; Eltun, Ragnar and Sjursen, Helge (2011) Repeated use of green-manure catch crops in organic cereal production - grain yields and nitrogen supply. Acta Agriculturae Scandinavica Section B Soil and Plant Science, 61 (2), pp. 164-175.

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Online at: http://www.informaworld.com/smpp/section?content=a934313850&fulltext=713240928

Summary

By restricted access to manure, nitrogen (N) supply in organic agriculture relies on biological N-fixation. This study compares grain yields after one full-season green manure (FSGM) to yields with repeated use of a green-manure catch crop. At two sites in south-eastern Norway, in a simple 4-year rotation (oats/wheat/oats/wheat), the repeated use of ryegrass, clover, or a mixture of ryegrass and clover as catch crops was compared with an FSGM established as a catch crop in year 1. The FSGM treatments had no subsequent catch crops. In year 5, the final residual effects were measured in barley.
The yield levels were about equal for grains with no catch crop and a ryegrass catch crop. On average, the green-manure catch crops increased subsequent cereal yields close to 30%. The FSGM increased subsequent cereal yields significantly in two years, but across the rotation the yields were comparable to those of the treatments without green-manure catch crop. To achieve acceptable yields under Norwegian conditions, more than 25% of the land should be used for full-season green manure, or this method combined with green-manure catch crops. The accumulated amount of N in aboveground biomass in late autumn did not compensate for the N removed by cereal yields. To account for the deficiency, the roots of the green-manure catch crops would have to contain about 60% of the total N (tot-N) required to balance the cereal yields. Such high average values for root N are likely not realistic to achieve. However, measurement of biomass in late autumn may not reflect all N made available to concurrent or subsequent main crops


EPrint Type:Journal paper
Keywords:aboveground biomass; cover crop; legume; phosphorus; potassium; red clover; ryegrass; soil mineral N; white clover
Subjects: Crop husbandry > Crop combinations and interactions
Soil > Nutrient turnover
Farming Systems > Farm nutrient management
Research affiliation: Norway > Bioforsk - Norwegian Institute for Agriculture and Environmental Research > Bioforsk Arable Crops Division
Norway > Bioforsk - Norwegian Institute for Agriculture and Environmental Research > Bioforsk Organic Food and Farming Division
Deposited By: Løes, Anne-Kristin
ID Code:18531
Deposited On:31 Mar 2011 10:43
Last Modified:31 Mar 2011 10:43
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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