Nitrogen recycling in a succession bean-corn/canavalia-bean in ferrallitic red soil

Abstract

Green manures are based on the use of solar energy to generate plant biomass of high nutritional quality, on the other hand, the isotopic method allows measuring the absorption of nutrients by the plant, more accurately and in less time than the conventional method. An experiment was developed under field conditions to determine N recycling in a common bean-corn succession associated with canavalia-common bean. The experiment was conducted on Red Ferrallitic soil. For the association of corn with canavalia, one furrow of canavalia was planted for every two furrows of corn. The common bean was inoculated with Rhizobium strains and 15 kg N ha-1 was applied as starter and to corn 39 kg N ha-1 in the form of ammonium sulfate 3,4 % 15N (atomic excess) to determine the percentage of N derived from fertilizer, soil and residue. The yield and dry matter extraction by corn behaved according to the plant population in the crop, the lower corn yield in the plots with canavalia could be corrected with an increase in corn planting density, the bean grain yield, harvested after the incorporation of canavalia increased. The residual effect of legumes on subsequent crops was demonstrated when it was determined by nuclear techniques that the incorporated biomass accumulated 43,6 kg N ha-1. The benefits derived from the implementation of crop associations on soil fertility and forage production in livestock areas in Cuba are discussed.