The influence of catch crops for green manure and straw on the infiltration of atmospheric precipitation and nitrogen leaching

Lysimetric experiments, conducted during 2002-2008 at the Voke Branch of the Lithuanian Institute of Agriculture, were designed to determine the effects of green manure crops red clover (Trfolium pratense L.), fodder radish (Raphanus sativus var. oleiformis L.) and barley (Hordeum vulgare L.) straw, intended to stabilise soil fertility, on nitrogen leaching and atmospheric precipitation infiltration. The lysimeters were packed with a sandy loam Luvisol (LVh). It was found that green manure crops grown after cereal harvesting reduced atmospheric precipitation infiltration during the autumn season by on average 19.4-21.7%, and by 7.0-8.3% per year. Clover produced more biomass (0.407 g m(-2)) with which more nitrogen (7.35 g m(-2)) was incorporated into the soil, and this increased nitrogen concentration in the lysimetric water as well as nitrogen leaching losses. The effect lasted for up to 12 months. During the autumn season, post crop fodder radish effectively utilized mineral nitrogen and at the same time reduced infiltration of precipitation. Due to the interaction of these factors leaching losses declined by 24.2%, compared with those occurring in the soil not applied with organic fertilisers and by 48.9% and 47.0%, compared with the treatments with straw + N(30) or clover and straw incorporation. Incorporation of straw with mineral nitrogen addition (N(30)) increased nitrogen concentration in lysimetric water only in the first months after its ploughing in, while the total annual nitrogen leaching increased by on average 12.9%.