LAUSR

Atmospheric nitrogen biologically reduced in legumes root nodule and accumulated in their postharvest residues may be of great importance as a source of this macronutrient for succeeding crops. The aim of the study was to determine nitrogen uptake by winter triticale from pea postharvest residues, including N fixed from atmosphere, using in the study fertilizer enriched with the 15N isotope. Triticale was grown without nitrogen fertilization at sites where the forecrops had been two pea cultivars (multi-purpose and field pea) and, for comparison, spring barley. The triticale crop succeeding pea took up more nitrogen from the soil (59.1%) and less from the residues of the forecrop (41.1%). The corresponding values where the forecrop was barley were 92.1% and 7.9%. In the triticale, the percentage of nitrogen derived from the atmosphere, introduced into the soil with pea crop residues amounted to 23.8%. The amounts of nitrogen derived from all sources in the entire biomass of triticale plants grown after harvesting of pea were similar for both pea cultivars. The cereal took up more nitrogen from all sources, when the soil on which the experiment was conducted had higher content of carbon and nitrogen and a greater amount of N was introduced with the pea residues. Nitrogen from pea residues had high availability for winter triticale as a succeeding crop cultivated on sandy soils.