SUMMARY
PENELITIAN HIBAH BERSAING
TAHUN 2010
JENIS PENELITIAN/PENGABDIAN : Hibah Bersaing
JUDUL PENELITIAN : Peningkatan Efisiensi Pemupukan Nitrogen Pada Tanaman Kedelai Dengan Penghambat Nitrifikasi dari Berbagai Tumbuhan Mengandung Tanin
KETUA PENELITI/PENGABDIAN : Djoko Purnomo, Prof. Dr. Ir. MP ANGGOTA : Suryono, Ir. MP
Triono D. Sulistyo, Ir. MP
SUMMARY
Djoko Purnomo, Suryono & Triyono D. Sulistyo, Increasing the Nitrogen Fertilizer Efficiency in Soya Bean Crop Cultification by Nitrification Inhibition from Several
ContainingTannin Plant
Cultivation of crops on marginal land such as forest lands with agroforestry systems requires careful study. The research is a program of biological soil fertility management to test and develop biological nitrification inhibition strategies in soybean cultivation-based trees stand. The object of the research is developing the soya cultivitation technology in agroforestry system (Gmelina dan Eucalyptus base) by the study of: characteristic of tanin nitrification inhibition substance in Gmelina and Eucalyptus litter; characteristic of microenvironment below gmelina and eucalyptus and agroforestry farmer in soya cultivitation; respon of soya bean Grobogan and Kaba variety to the low irradiaton; and respon of soya bean to the N, P, Mn and Mo fertilizer below Gmelina dan Eucalyptus standing crop.
The yield of the preview research indicate (based on polyphenol and lignin contain) that all of the litters on the research location can be used for inhibiting nitrification. Combined with C,N ratio litter requirement (> 25%), the litter which can be for inhibiting the nitrification process are Mahogani, Jackfruit, Mango, Breadfruit, and Teak litters. Gmelina and Petai litter not recommended for inhibiting nitrification process (C,N ratio < 25). The experimental results also prove that there are differences in soil nitrification potential, the population of bacteria oxidizing NH4+ and NO
2- oxidizing bacterial populations were significantly different (p <0.01). This
indicates that the quality of inputs of organic material (litter) to control the rate of nitrification in order to reduce N leaching soil, thereby increasing the efficiency of nitrogen fertilizer.
The first year research results concluded that the content N element in Cawas RPH soil due to low since nitrification process, oxidized by bacteria, and leaching.
Plant litters those can be for using nitrification inhibition are: Mahogany, Teak, Jackfruit, Mango, and Bread fruit. The sequence of litter quality as nitrification inhibitor from the best to the lowest are Mahogany > Teak > Jackfruit > Mango > Breadfruit. The potential soil nitrification inhibitor from high to low are litter polyfenol containt, lignin, (L+P)/N ratio and tannin containt. The need of mineral nutrition for soybean unavailable in the soil, so fertilizer is necessary. Fertilization of N and P respectively 25-50 and 50-100 kg ha-1, as well as Mn and Mo
make soybean plants (variety Kaba and Grobogan) capable of producing 0.86 tons ha-1 (average),
