Cultivo de leguminosas e manejo da cobertura do solo para a supressão de Plantas daninhas em cana-de-açúcar

Abstract

The practice of green manure provides the suppression of weeds in agricultural systems and can be understood as an alternative to the use of herbicides and a strategy within an integrated weed management. Therefore, the objective of this study was to evaluate the suppressive effect of five legumes as green cover and also as mulch on weeds in sugar cane area, compare the results with the use of herbicides and describe the effect on the productivity of cane sugar. This work was carried out under field conditions in the plant Cansanção of Sinimbu, Jequiá Beach, AL. In the first experiment the legumes were grown for 80 days (green ground cover phase) evaluated the establishment of weeds in the area by quantifying the number of plants per square meter, the biomass and diversity of plants and was evaluated biometrics and the biomass production of pulses in two periods: the 50 and 80 days. In the second experiment the legumes were managed to form mulch for 60 days are also evaluated the suppression of weeds. To compare the ability to control weeds in both experiments herbicide treatments were used. The experimental design was a randomized block with four replications and plots of 48 m². On the green ground cover layer was found that after 50 days of cultivation Crotalaria juncea was the Best alternative control option weed with over 80% efficiency compared to the control; following came Crotalaria spectabilis and Crotalaria ochroleuca with 60% efficiency; at 80 days of C. juncea cultivation remained with the best ability to suppress weeds, however, Crotalaria breviflora did not show the character of suppression. In soil mulch phase, from mulch formation of tipping the five legumes studied did not control the weeds in the same efficiency as herbicides applied in post + pre-emergence. The tipping, however, proved to be so effective in weed control on the use of herbicides in pre-emergence, which was observed at 60 days of cultivation of cane sugar. Failure to control weeds up to 60 days of cultivation of cane sugar brought losses around 35% losses, both in agricultural productivity (TCH) and on industrial performance (TPH). In all forms of ground cover management, the Poaceae family was the most prevalent weed species. Eragrostis ciliaris stood out as the kind of greater relative importance in most areas despite being a species that reproduces only by seed, dense tillering is a characteristic which explains its high relative density in these areas,