Swine waste effluent and other agro-industrial wastes as organic fertilizer for vegetables

Using the right kind and amount of agro-industrial wastes as amendments to lahar deposit areas can solve the problems of waste disposal and low productivity of lahar-affected areas. To address the concerns on waste disposal and productivity in these areas, Gonzales et al. (PAC) conducted the project "Enhancing the fertility and productivity of lahar deposit areas with the use of agro-industrial wastes." The effects of swine waste and other agro-industrial wastes (distillery sludge and beer sludge) on vegetables were tested in the lahar deposit areas of Barangay San Martin, Concepcion, Tarlac and Barangay San Roque, Magalang, Pampanga. Tomato (cv Apollo), okra (cv Smooth Green), and onion (Tagalog) were used as test crops.

In the Tarlac site, pig waste was applied 27 days after transplanting. Inorganic N was applied in two doses, at 14 days and 30 days after planting. Experimental crops were grown without irrigation. The soil at the site had pH of 6.6, 0.5% organic matter, 14 ppm Olsen’s P, and 152 ppm K. The site in Pampanga had at least 2 m deep lahar sediment. All agro-industrial wastes were applied to tomato, okra, and onion after furrowing or prior to planting.

Findings:

• Among the waste materials used in the study, pig waste slurry contained the highest concentration of phosphorus (P) and microelements. In terms of nitrogen, distillery and beer sludge contained higher concentrations than pig waste sludge (slurry and effluent) (Table 1).
• Under Tarlac conditions, fertilizer application affects yield of lahar-grown tomato. Applying 60-kg N from inorganic fertilizer (IF) or 60-kg N from pig waste effluent (PWE) increased yield of tomato by 235% and 197%, respectively.
• Applying 60-kg N from IF and 60-kg N from PWE produced 29.98% higher yield than applying 120-kg N from IF. Increasing the amount of N from PWE did not produce significant difference in yield. Similarly when using IF alone, increasing the amount of N applied from 60 to 120 kg did not produce significant difference in yield. Yields obtained from applying 60-kg N from PWE alone was lower than the yield obtained from applying 60-kg N from IF alone.
• Growing okra and onion in lahar areas during postmonsoon months or under water limiting environment resulted to low yields despite supplemental irrigation.

Table 1. Nutrient composition of sludge tested as organic fertilizer

Source: PCARRD, 2003. Highlights 2002, Los Banos, Laguna.

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