LARGE-LEAVED LUPIN (Lupinus polyhyllus Lind.) AND EARLY RED CLOVER (Trifolium pratense L.) AS GREEN MANURE GROPS

Trials with large-leaved lupine (‘Lupi’) and early red clover (‘J?geva 433’) as green manure were carried out to study their suitability for green manure production. The trials were carried out on the trial fields of the Estonian University of Life Sciences in 2008–2010. Biomass production abilities of various plants grown with or without a cover crop were examined. In the experiment, different green manure crops with undersowing and pure sowing were compared for amounts of N, C, P, K and organic matter driven into soil and their effect on cereal yield. The value of these green manure crops as manure was estimated, based on their effect on the succeeding cereal yield. From green manure plants, sown with cover crops, red clover gave the best results, while large-leaved lupine was better grown as pure crop (18% more biomass than red clover in similar situation). Biomass from large-leaved lupine, grown without cover crop, was also the most efficient in returning nutrients into the soil. Pure green manure had bigger effect and it lasted longer if grown as undersowing.