ISSN:
1573-0867
Keywords:
available N
;
cover crop
;
crop uptake
;
green manure
;
incorporation
;
N2O
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract Nitrogen retention and release following the incorporation of cover crops and green manures were examined in field trials in NE Scotland. These treatments reduced the amounts of nitrate-N by between 10–20 kg ha-1 thereby lowering the potential for leaching and gaseous N losses. However, uptake of N by overwintering crops was low, reflecting the short day-lengths and low soil temperatures associated with this part of Britain. Vegetation that had regenerated naturally was as effective as sown cover crops at taking up N over winter and in returning N to the soil for the following crop. Incorporation of residues generally resulted in lower mineralisation rates and reduced N2O emissions than the cultivation of bare ground, indicating a temporary immobilisation of soil N following incorporation. Emissions from incorporated cover crops ranged from 23–44 g N2O-N ha-1 over 19 days, compared with 61 g N2O-N ha-1 emitted from bare ground. Emissions from incorporated green manures ranged from 409–580 g N2O-N ha-1 over 53 days with 462 g N2O-N ha-1 emitted from bare ground. Significant positive correlations between N2O and soil NO3 - after incorporation (r=0.8–0.9; P〈0.001 and r=0.1–0.4; P〈0.05 for cover crops and green manures, respectively) suggest that this N2O was mainly produced during nitrification. There was no significant effect of either cover cropping or green manuring on the N content or yield of the subsequent oats crop, suggesting that N was not sufficiently limiting in this soil for any benefits to become apparent immediately. However, benefits of increased sustainability as a result of increased organic matter concentrations may be seen in long-term organic rotations, and such systems warrant investigation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009825606341
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