Influence of protein degradation and protein content in cut Lolium multiflorum leaves on the delay in ammonia volatilisation
1995
Marstorp, H. (Sveriges Lantbruksuniv., Uppsala (Sweden). Inst. foer Markvetenskap)
Green manures are often cut serveral times during the growing season with the aim of increasing production and N2-fixation. The aim of this investigation was to determine the relation between ammonia volatilisation from cut Lolium multiflorum leaves, not-incorporated in soil and protein degradation. Special attention was paid to the length of the period between cutting and the start of volatilisation. The decrease in leaf protein-N and increase in free amino acid- and ammonia-N followed patterns similar to those observed during the senescence of cut leaves. Such resemblance suggests that senescence may play an important role in ammonia formation. Fungal growth was observed on day 7, and microbial degradation may also have been of importance especially during the latter part of the 21-day incubation period. Ammonia volatilisation started once the pH of the leaves had reached 8.6. The period between the cutting of the leaves and the start of ammonia volatilisation was linearly related to the protein content of the leaves. Under field conditions this means that the period from cutting until a green manure must be incorporated depends on its protein content: the higher the protein content the shorter the period.
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