Abstract

Green manures can be used as an N source for agricultural crops as a substitute for inorganic N fertilizers. The effects of using green manures on leaching and uptake of N by spring barley (Hordeum vulgare L.) were evaluated in a 2-yr lysimeter study. Ryegrass (Lolium perenne L.) and red clover (Trifolium pratense L.) labeled with N-15 were applied in May of the first year at 160 kg total N ha(-1). Simultaneously, (NH4NO3)-N-15-N-15 was applied at 80 kg N ha(-1) to additional lysimeters and others were left without N additions (control). During the second year, all lysimeters, except the control, received 80 kg N ha(-1) as unlabeled NH4NO3. The cumulative, average loads of total N leached during the two years were: 37 (control), 62 (NH4NO3), 50 (ryegrass manure), and 73 (red clover manure) kg ha(-1). The differences among the treatments were not significant (P > 0.05), but the control had significantly smaller (P < 0.05) leaching loads than the treatments. About 24% of ryegrass- and red clover-derived N and 43% of NH4NO3 were removed through spring barley grain and stover during the two growing seasons. Thus, the N use efficiency in barley was substantially larger when grown with inorganic N fertilizer than when grown with green manure. Viewed in combination with the tendency for larger N leaching loads under red clover manure, claims about water quality benefits of legume-based green manures should be evaluated with regard to the timing of N release and demand for N by the plant

Published in

Journal of Environmental Quality
2004, Volume: 33, number: 5, pages: 1786-1792
Publisher: AMER SOC AGRONOMY

SLU Authors

• Bergström, Lars

  • Department of Soil Sciences, Swedish University of Agricultural Sciences
    

• Kirchmann, Holger

  • Department of Soil Sciences, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Agricultural Science


Publication identifier

DOI: https://doi.org/10.2134/jeq2004.1786

Permanent link to this page (URI)

https://res.slu.se/id/publ/2957