Effects of compost on lettuce (Lactuca sativa) yield and soil biochemical properties

Resumo

Amended soils with compost produced from livestock effluents can increase soil fertility and crop productivity. The aim of this work was to assess the effect of the fertilization with a compost on the soil enzymatic activity and yield of a lettuce crop.  An experiment was carried out under field conditions with the following treatments: control without fertilization; mineral N fertilization with 85 kg N ha−1 (Ni85); fertilization with compost in pellets (CP170N) at N dose of 170 kg ha−1; fertilization with CP at N dose of 85 kg ha⁻¹ together with mineral N at 42.5 kg ha^-1(CP85N+Ni42.5). The fertilization increased the lettuce biomass compared with the control treatment; the pelletized compost showed similar yields (P >0.05) than those obtained with the mineral N fertilization. The acid phosphatase and the total microbial biomass increased significantly in the soils fertilized with CP170N treatment. However, the alkaline phosphatase and b-glucosidase were similar between the treatments. The acidic pH of the soil may have decreased the alkaline phosphatase activity. The application of the pelletized compost at a dose of 170 kg N ha^-1 showed the best agronomic behavior regarding the lettuce yield, the soil microbial biomass and the acid phosphatase activity.