Efecto de los cultivos cobertura sobre la recarga de agua, nitrógeno en el suelo y la productividad del maíz

In Uruguay agriculture been increasingly important in many ways in many cases generating increasing continuous cropping rotations and handling based on obtaining one crop per year. In these situations leaves a long fallow period in the winter, when the ground is bare. To achieve sustainability of the production system based on grains, should improve the carbon balance through an increased supply of plant biomass. In this sense, hedge crops are agronomic tool ideal because they play the role of providing carbon, maintain the soil covered, recycle nutrients and produce a new entry to the system stubble (Siri\ and Ernst, 2011). This paper seeks to test the effect that different cultures have winter covers the evolution of moisture and nitrate in soil and its impact on the cultivation of maize. For this experiment was conducted in the department on a floor Paysandú Eutrico Brunosol Tipico. The design was a randomized complete factorial with three replications hedges being the main plot and nitrogen doses lower plot. The cover types were used, four grasses (Avena Byzantine strigosa Avena, Lolium multiflorum and Triticale), three legumes (Trifolium alexandrinum, Vicia sativa, Pisum sativum) and composite (Sinapis alba). The fertilizer used to V6 stage of corn were 0 and 50 units of nitrogen. Planting of all coverages was on May 22 and its production was to begin on October 6 where the chemical fallow. The corn planting was held on December 9. In general terms, the conclusions are that the use of covers did not harm the availability of water for planting the corn crop, due to the large amount of rainfall that occurred in the fallow, which allowed a recharge of water in the soil profile. In the case of nitrogen in the soil, the covers decreased the levels of this nutrient compared to the clean fallow, especially the grasses. Finally, the highest yields of the corn crop were achieved on clean fallow with and without fertilization, also without differences with the previous one are the covers of alexandrine clover, pea and vetch, all with N fertilization. The lowest yields were obtained on grasses.