Comparison of postharvest practices used for cereal straw decomposition in a clay loam soil

摘要

During 2008-2011, model field experiments were carried out at the Joniskelis Experimental Station of Lithuanian Research Centre for Agriculture and Forestry on a clay loam Endocalcaric Endogleyic Cambisol. The study was aimed to establish the comparison of various postharvest practices (mineral nitrogen fertiliser alone or together with a bioactivator Penergetic k, livestock slurry, red clover biomass and straw incorporation in the soil by a stubble cultivator at a 10 cm depth) on the acceleration of the initial (nine-month period) decomposition of winter wheat straw. During this period, straw mass decomposition intensity was 20.7-29.1%, carbon (C) concentration decreased by 6.5-22.8%, while an increase in nitrogen (N) by 1.1-2.2 times was observed. The highest straw decomposition rate was recorded when after straw incorporation autumn was warm and humid. That year straw mass C to N ratio (C/N) was 38-46. Under less-favourable autumn conditions, the highest decomposition of straw was achieved, having applied mineral N (with and without Penergetic) and livestock slurry and having incorporated the straw in the soil (C/N = 40-55). A slower decomposition rate was observed for the straw spread on the soil surface with mineral N addition or on undersown red clover.