Effect of Green Manuring, Mulching, Compost and Microorganism Inoculation on Size and Yield of Lettuce

摘要

Organic vegetable and flower farms represented only 4.4% of more than two hundred thousand vegetable and flower farms in Brazil (2006). Lettuce is one of the most important vegetables, but few organic studies have been conducted with this vegetable. Therefore, research is needed to improve organic production systems for farmers and increase their market share. To study the effect of several organic treatments, an experiment was conducted at the experimental station of APTA-UPD, in Sao Roque, S?o Paulo, Brazil, during 2008-2009. This experiment consisted of testing various combinations of green manuring (Crotalaria juncea), mulching (grass - Brachiaria spp.), compost (horse manure compost and vermicompost) and Azospirillum brasilienses. The effects of these treatments for the organic production system were evaluated, based on the diameter, fresh weight and dry mass of lettuce. The experimental design used consisted of randomized blocks, with ten treatments each and five replications. The treatment with green manuring, mulching and Azospirillum brasilieses (GM_1M_1Az_3) recorded the highest lettuce diameter (36.3 cm) and fresh weight (643.0 g); while the corresponding lowest values were recorded in the control (without green manuring, without mulching and with horse manure compost) with 32.3 cm and 461.6 g, respectively. The highest dry mass (22.46 g) was obtained with the treatment consisting of green manuring and horse manure compost without mulching (GM_1M_0C_2). Analysis was also made to study the effect of Azospirillum treatments along with other organic treatments on lettuce variables. It was observed that treatment with green manuring, mulching and Azospirillum (GM_1M_1Az_3) recorded maximum lettuce head diameter (36.3 cm), fresh weight (643.0 g) and dry mass (21.3 g).