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

Abstract

ABSTRACTDuring 2008–2011 model field experiments were carried out at the Joniškėlis 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 fertilizer 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 (DIM) was 20.7–29.1%, carbon (C) concentration decreased by 6.5– 22.8%, while an increase occurred in nitrogen (N) 1.1–2.2 times. 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.