Potencial fertilizante de adubos orgânicos à base de esterco bovino e sua utilização na produção de mudas de alface

Abstract

Agricultural production generates a diversity of organic waste, including manure, which is often deposited on the soil without adequate treatment, that could damage the environment. Treatment processes such as composting and vermicomposting, enable reuse of these materials as organic fertilizers, for example in the production vegetables. This study aimed to quantify the nitrogen mineralization added to the soil by organic fertilizers produced based on cattle manure and evaluate the potential of these organic fertilizers in the lettuce seedlings production. First it was evaluated the nitrogen mineralization and the index of efficiency of three organic fertilizers. The treatments were: soil (control), soil + vermicompost manure produced from a compound of straw and manure, and soil + manure in nature . 360.5 mg of total nitrogen kg-1 of soil were by organic fertilizers. The results show that the efficiency index of the nitrogen treatments were: soil + vermicompost manure: 0.22; soil + vermicompost produced from a compound of straw and manure: 0.27, and soil + manure "in natura": 0.23, in 112 days. In the second stage of the study the growth of seedlings of lettuce (Lactuca sativa L.) in substrates with these three organic fertilizers was evalued and compared to a commercial substrate. The fertilizers were used in the formulation of the substrates in the proportions of 20, 40, 60, 80 and 100% (v / v). The use of cattle manure in concentration of 20% to 60% and the evaluated vermicomposting, in dosages increasing from 20%, results in the production of lettuce seedlings with similar quality to the seedlings with the commercial substrate.