Lodos residuales composteados: una alternativa de sustrato para la producción de planta de "Agave durangensi"

Residual water that is generated in Durango City, is generated from domestic origin containing organic and solid pollutants, due to 490,524 citizens. This daily flow has generated the amount of 2'831,540.47 ft3 as total volume of residual mud in six aeration lagoons. Forest planting programs in Durango have been increased lately with a main purpose to recover the forest cover in the degraded areas in the forest. The National Forest Commission (CoNaFor) in Durango produced 12'910,410 plants during 2002, and 2'500,000 were Agavaceas. This involves the use of great amount of substrate to produce the goals; it increases the production costs. It is recommended the residual composted mud be an alternative as a substrate to reduce the cost for Agaves plants demand, which has increased due to the origin denomination NOM-070-SCF-1994, that has acquired the mezcal drink in Durango, and to solve the residual mud problems in the residual lagoons. In an random design 3 treatment and 3 replications were tested: Treatment 1. Fresh Mud (88.184 pounds); treatment 2 Fresh Mud (88.184 pounds) mixed with of hay, (22.046 pounds) dry oat straw (22.046 pounds) and fresh livestock manure (22.046 pounds); treatment 3 agricultural soil from the Instituto Tecnologico Agropecuario No 1 (ITA No. 1). Measured variables were: total and fecal number of coliform; and before and after composted process; physic and chemical characteristics; and the main heavy metals. Once data were obtained, a statistic program from The Facultad de Agronomia of the University of Nuevo Leon State (FAUNAL) was used. Significant statistical differences were obtained among treatments; 600 NMP (more probable number) of fecal coliforms for treatment 2 after composting; a low value compared to the official standard allowed for public use with indirect contact (NOM, 1987). Treatment 2 result shows the composting effectiveness, due to the fact that residual mud act as an additional inoculums in the degradation of organic matter and fecal coliform decay. According to the physical and chemical analysis results, the pH was 6.5, the fertility in treatment 2 shows the highest nitrogen percentage, 0.58 percent and organic matter 11.62 percent. The heavy metals values in treatment 2, were statistically lower compared to treatment 1 where pure composted residual muds were used. According to the Protecting Environmental Agency of The United States (US-EPA 1993), these values are below the maximum allowed limits.