Influ?ncia da cobertura morta com palha de leguminosas e gram?neas no desempenho de alface (Lactuca sativa L.) sob manejo org?nico

• Ano de defesa: 2005
• Autor(a) principal: Oliveira, Fabio Freire de
• Orientador(a): Guerra, Jos? Guilherme Marinho
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal Rural do Rio de Janeiro
• Programa de Pós-Graduação: Programa de P?s-Gradua??o em Agronomia - Ci?ncia do Solo
• Departamento: Instituto de Agronomia
• País: Brasil
• Palavras-chave em Português: cobertura morta; plantas de cobertura; agricultura org?nica
• Palavras-chave em Inglês: mulch; cover plants; organic agriculture
• Área do conhecimento CNPq: Agronomia
• Link de acesso: https://tede.ufrrj.br/jspui/handle/tede/263

The present work had as objective to study the effect of usage of mulching of leguminous and grass plants on yeld of lettuce (Lactuta sativa), cultivated under organic management. Two series of experiments were conducted. In the first one, the ideal amounts of dried straw for mulch formation were determined and further effect of application of different sources of leguminous and grass plants. In both series, infestation of spontaneous grass, the mineral nutrition and yield of lettuce, in two consecutive cycles, were evaluated. The treatments in the first series consisted of two sources (cameroon grass and pigeon pea) and the amount (0, 1.25, 2.50 and 5.00 kg/m2 of dry straw) of mulching in a randomized block design with factorial arrangement. The mulching had been applied before the beginning of the first cycle of lettuce crop, evaluating in the following cycle the residual effect. The suppression of invading grass occurred in similar way for both covering sources revealing particularly effective in amount of 2.5 kg/m2 of straw, which eliminated the necessity of weedings in the two cycles of culture, without reduction on lettuce yield. The average weight of the head of lettuce was bigger in the presence of the pigeon pea straw in both cycles. Increasing the amount of pigeon pea straw increased the amount of nitrogen in above ground part while in the presence of cameroon straw reduced this nutrient in the same part of the plant. So, the antagonism among sources, concerning the supply of N for lettuce reflected in the distinct behavior of the lettuce crop in the presence of the two coverings, in what it benefited from the presence of the covering formed from the leguminous. In the second series of experiments, the treatments consisted of different sources of straw using as experimental design in a randomized block design. The treatments consisted of: no straw; pigeon pea straw, mucuna (Mucuna pruriens) straw, crotalaria (Crotalaria juncea) straw, gliricidia (Gliricidia sepium) straw and eritrina (Eritrhina poepigiana) straw, cameroon (Penissetum purpureum), bamboo (Bambuza sp) leaves, and the bagasse of sugar cane (Sacharum sp.). The amount of straw applied was of 2.5 kg/m2 and the evaluations were carried out through two consecutive cycles of lettuce crop. The presence of leguminous straw provided a greater development of the lettuce, when compared with the absence of straw and the presence of cameroon straw, increasing the diameter as well as the fresh weight. As observed in the previous experiments, the straw of leguminous plant increased the nitrogen accumulation at above ground part when compared with cameroon straw, and the absence of the others mulching. However, differences between the leguminous straw had not been detected. On the other hand, all others straw sources reduced the population of the invading grass, with an average reduction of 76%. In the following cycle of the crop, in the presence of leguminous straw, the lettuce performance maintained higher when compared with mulching formed with cameroon straw.