Comparison of three systems of decomposition of agricultural residues for the production of organic fertilizers

Abstract

Organic wastes (OW) of diverse nature must be subjected to controlled decomposition processes to avoid risks of contamination and obtain products useful for agriculture. The objective of the present study was to compare over time physical, chemical and enzymatic parameters of OW transformed as vermicomposting (VC), semicomposting (SC) and composting (CP) for elaboration of organic fertilizers. A mixture of bovine manure and sawdust was subjected to each of three systems for 183 d. Temperature, total N (Nt), organic C (OC), C/N ratio, pH, enzymatic urease activity (EUA), germination index (GI) and electrical conductivity (EC) were measured throughout the time of study. The variables evaluated showed significant differences between time and treatment. The temperature ranged between 20 and 34 °C in VC and SC, while in CP between 20 and 61 °C. All three systems reduced the C/N ratio to less than 15/1. The CP product had higher pH, EC, and EUA values than both VC and SC. The VC product had the highest GI values. All the products obtained at 183 d were within the parameters to be considered as organic fertilizers, but the SC product transformed into an organic fertilizer fastest and had least water usage.

Modelos de predicción del índice de madurez de abonos orgánicos producidos con tres procesos de transformación

“…Los riegos se aplicaron diariamente en VC para mantener la humedad entre 75 a 85% (Castillo et al, 2010) y a criterio para mantener la humedad de 50 a 60% en SC y CP, lo que se determinó mediante la prueba al tacto (NRAES 1999;Soto y Muñoz, 2002). Las mezclas sometidas a SC y CP se removieron mecánicamente cada 28 días para homogenizar el contenido y reducir la formación de zonas anaerobias (Sánchez-Rosales et al, 2017).…”

Soil organisms and microorganisms; their function as controllers of plant pathogens

“…Moreover, vermicompost has an essential role to promote life in the soil by improving the texture and promoting satisfactory levels of macro and micronutrients. 12 In addition, during vermicomposting, the Californian Red worm (Eisenia foetida) ingests organic matter which progressively decomposes and fragments. This matter is made up of microorganisms including a large number of fungi.…”