Use of Vermicompost and Their Effect On Physical and Chemical Properties In An Acid Soil

In Western Mexico, several organic wastes such as molasses, cattle manure, sugarcane bagasse, crop residues (banana, rice, sorghum and maize), lemon shell and coffee pulp have become a source of environmental contamination. Their use is a viable alternative in vermicompost production by earthworms as a profitable activity for many producers and for soil amendment. However, there are not available research results about the effects on physical and chemical properties in acid soils. This work evaluates the effects of commercial vermicompost, produced from coffee pulp on some physical and chemicals properties in an acid soil. The experiment was carried out under greenhouse conditions, in PVC columns 7.5 cm diameter and 60 cm long containing samples from the upper layer 0 – 0.30 m of a medium-textured, typic oxisol, collected in a cultivated sugarcane area in the Matatipac Valley, Nayarit, Mexico. The preliminary soil chemical analyses showed the following parameters: pH 4.9, OM content 0.80% and EC 0.130 dS/m. While vermicompost of coffee pulp had: OM content 49.38%, pH 5.81, total C 28.64%, total N 2.44% and total P 3729 ppm. Five levels of vermicompost (equivalent to: 0, 20, 40, 60, and 80 ton/ha, dry weight) were evaluated during 120 days and sampled each 30 days under a complete randomized design with four replicates. Physical properties of the soil such as porosity percent, particle density and bulk density were determined by specific gravity bottle method and cation exchange capacity was estimated by ammonium saturation method. Chemical parameters such as pH, organic matter (OM), C, electrical conductivity, available nitrogen, phosphorous, potassium, Al and Fe were determined. Results shown that the porosity, particle density and bulk density values were not affected by vermicompost application. On the contrary, the casting application reduce pH levels in soil with 40 and 80 ton/ha compared with control (0 ton/ha). OM was increased (0.28%) in acid soil columns only the first 30 days after worm casting application. Electrical conductivity was increased in all soil columns enriched with vermicompost at the 30 and 60 days. Finally Al and Fe contents showed difference between treatments. Important changes concerning the nutrimental and chemical characteristics in acid soil due to the coffee pulp worm casting application were observed.