Asimilarea azotului și productivitatea culturilor în diverse procedee de fertilizare cu paie

Abstract

In order to identify efficient and rational procedures for the valorization of straw surpluses as fertilizer, the authors studied their influence on plant production and nitrogen supply to plants. The experiment was established on clayey-loamy poorly eroded ordinary chernozem, in Cahul district, Republic of Moldova. The experimental design included variants consisting in the application of straw that was not supplemented with nitrogen and variants in which straw was supplemented with low doses of nitrogen. The combination of straw with sheep manure as well as with high doses of chemical fertilizers containing nitrogen and phosphorus was also tested. Straw and associated fertilizers were applied once every four years, in 2009, 2013 and 2017, in July. The most efficient variant consisted in the procedure by which 4 t/ha of chopped straw was spread on the stubble over which chemical fertilizers N₂₀ P₂₀ were distributed. This procedure ensured an average annual increase of 480 kg/ha of conventional wheat. The phenomenon of crop yield decrease because of the incorporation of straw applied separately without nitrogen did not occur in this experiment. This is due to the ability of chernozem soils to form, through humus mineralization, enough nitrogen needed for the microbiological processing of straw applied in the summer. Thus, the soil type and climatic conditions in the South of the Republic of Moldova allow to incorporate straw surpluses as a fertilizer, including without being supplemented with nitrogen-containing fertilizers.