Utilization of Effluent from Biogas Production as Nitrogen Source for Guinea Grass (Panicum maximum Jacq.) Grown on Kamphaeng Saen Soil

Abstract

Effluent from biogas production (EFB) of liquid swine wastes was tested as nitrogen source and as irrigational water for guinea grass planted in Kamphaeng Saen soil. The EFB was applied weekly at 40,000 l/rai (6.25 rai = 1 ha) for the whole growing period. With the mentioned rate, the EFB supplied nitrogen for the grass which was equivalent to 25 kg N/rai (156 kg N/ha). Inorganic fertilizer (IF) in the form of ammonium sulfate at the same rate as above was used as the standard treatment. Combination of the two treatments (1/2EFB + 1/2IF) and no nitrogen fertilizer (Ch) were set as an alternative and the check treatments, respectively. The experiment was conducted as field trial using RCBD with 4 replications. One crop of the grass was harvested 4 times monthly. The grass was planted for the total of 3 consecutive dry seasons. The results indicated that by using EFB, grass yield could be produced as much as using 25 kg N/rai chemical fertilizer. The grasses which received EFB or IF were more or less the same in nutrient amount and nutritional quality. The EFB could replace irrigational water for the whole planting period. It could substitute irrigational water as much as 160,000 l/rai/month (1,000,000 l/ha/month). With long-term application of the EFB, there were no change of Zn, Cu, pH and electrical conductivity of the soil. Some soil physical properties, such as state of aggregation, were likely improved. In addition, no increase of nitrate content in ground water was observed.