ISSN: 1659-2751

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Study of the Time of Stabilization and Nitrogen Mineralization Potential of Two Organic Fertilizers Produced with Sheep Manure and Horse Manure

Abstract

One of the technologies that can be incorporated into food production systems to supplement the fertilizer from industrial sources is organic fertilizers. In Costa Rica there is not enough information about organic fertilizers made from equine and ovine manure. The objective of this study was to determine the stabilization time, the mineralization of N and the N mineralization potential of manure fertilizers produced from equine and ovine manure. To prepare the organic fertilizers, 75 kg of excrete, 18.75 kg of sawdust for the equine mixture, and 37.5 kg for the equine mixture, 0.03 kg of yeast and 1.3 L of molasses were mixed. The organic fertilizers were sampled for 40 days to determine their stability through the C:N ratio. The mineralization of the N organic fertilizers was determined by incubating soil mixed with the organic fertilizer in bags for 12 weeks; each bag was filled with a mixture of 300 g of soil and an amount equivalent to 20 Mg/ha of organic fertilizer. The equine organic fertilizer stabilized after 25 days with a C:N ratio of 18:1, the ovine organic fertilizer stabilized after 38 days with a C:N ratio of 25:1. The equine organic fertilizer produced N immobilization during the 12 weeks of the incubation period. The ovine organic fertilizer manure produced N immobilization during the first six weeks and produced net N mineralization from week 8 to week 12. Although the ovine manure was lower in N content than the equine manure, it was higher in P, K, Ca and Mg content, and produced a net mineralization of N.

Key words: organic fertilizer, compost stability, equine manure, ovine manure, nitrogen immobilization, nitrogen mineralization.

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