Márcio Sampaio Pimentel

Seasonal response of edaphic bioindicators using green manure in Brazilian semi-arid conditions

The goal of this work was to evaluate the response of edaphic macrofauna, soil microbial biomass carbon, soil basal respiration, metabolic quotient and labile carbon of fumigated soil in a Fluvic Neosol. The experimental design was in randomized blocks, with five treatments (four green manure mix and one control) and four replications, and subsequent planting of melon (Cucumis melo L.) under semi-arid conditions in Juazeiro, Bahia State, Brazil, from August 2006 to August 2007. Soil samples were collected at a depth of 0-10 cm at 6 days before, and 117; 215 and 354 days after green manure mix planting. The results indicate that none of the attributes presented a significant difference for the treatments, but changed significantly in relation to the time of sample collection. The higher levels of soil microbial biomass carbon and labile carbon of fumigated soil were measured 117 days after planting. Soil microbial biomass carbon was inversely correlated with soil basal respiration and metabolic quotient, which increased as of 215 days after planting. At 354 days after planting, the edaphic macrofauna presented the highest density, richness, diversity and uniformity. Ants and beetles were most abundant in the areas studied.

Nutrient input on rocket growth and soil microbial activity in alley cropping of pigeon pea

The effects of organic fertilization combining cattle manure and pigeon pea shoots on the culture of rocket, planted with one or two plants per hole, including soil microbial biomass carbon, soil respiration, the metabolic quotient, soil fumigation labile carbon, and the dry matter content and total N, K, P, Ca and Mg contents in the leaves and roots of rocket were investigated. The experimental design was randomized blocks in a 2 × 2 × 2 factorial experiment: 0 and 160 kg ha-1 N from cattle manure, 0 and 160 kg ha-1 N from pigeon pea shoots, and one or two plants per hole, with three replicates. The most significant and positive correlations were obtained between leaf K × soil respiration, microbial biomass × leaf N and root Ca × metabolic quotient. The use of 160 kg ha-1 N from cattle manure along with 160 kg ha-1 N from pigeon pea shoots with two plants per hole resulted in a lower relative loss of C-CO2; the same result was found for the treatment of two plants per hole fertilized with 160 kg ha-1 N from cattle manure. Increased leaf and root N contents were observed in the treatment that combined two plants in each plot, fertilized with 160 kg ha-1 N from pigeon pea shoots, whereas the highest dry matter content was obtained by using one plant per hole, specifically: combining one plant per hole without fertilization; one plant per hole fertilized with 160 kg ha-1 N from pigeon pea shoots; and one plant per hole fertilized with 160 kg ha-1 N from cattle manure and pigeon pea shoots.