Soil nitrogen availability for crops | Augsnē esošā slāpekļa pieejamība kultūraugiem
2014
Karklins, A., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Agriculture | Ruza, A., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Agriculture
All possible sources of nitrogen available for crops before decision is made for the use of commercial fertilisers is necessary according to the requirements of Nitrate directive and adjustment documents regulating fertiliser use planning. Soil together with crop residues is one of nitrogen supplying sources, but quantifying amounts which could be released in plant available form and take part in yield formation by numerous reasons are difficult. Indirect soil nitrogen supply assessment could be derived from data obtained in field experiments where no-fertiliser-plot was used. Nitrogen off-take in this plot shows amount of nitrogen crops are able to obtain from soil and crop residues pool. In field conditions such factors were developed for winter rye and wheat, spring wheat and barley, winter and spring rape, as well as potatoes, and are based on 72 field experiments performed in Latvia within the 5 year (2008 – 2012) period. Share of soil nitrogen sources was also calculated for situations when crops were supplied with different nitrogen fertiliser amounts.
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