Paper Title
EFFECT OF DIFFERENT NUTRIENT MANAGEMENT APPROACHES ON SOIL INORGANIC NITROGEN FRACTIONS IN GROUNDNUT AND THERE CORRELATION WITH YIELD

Abstract
A field experiment was conducted during kharif (2021) season to study soil nitrogen fractions in groundnut under different nutrient management approaches in the central dry zone of Karnataka, using groundnut variety TMV-2 as test crop at Zonal Agriculture and Horticulture Research Station (ZAHRS), Hiriyur. The experiment was laid out in RCBD design with four treatments, five replications in an area of 20mx10m size of experimental plot. This experiment comprises the treatments viz., Organic farming - Seed treatment with Rhizobium and PSB + Recommended dose of FYM (10 t ha-1) + P equivalent basis of FYM; Natural farming - Seed treatment with beejamrutha + ghanajeevamrutha @ 1000 kg ha-1 before sowing + jeevamrutha @ 500 L ha-1 @ 30 days interval + mulching; POP (package of practice) - Seed treatment with Rhizobium and PSB + Recommended dose of FYM (10 t ha-1) + 25:75:37.5 kg ha-1 NPK + ZnSO4 @ 10 kg ha-1 + Borax @ 10 kg ha-1 + Gypsum @ 500 kg ha-1; Farmer's practice - 40:20:30 kg ha-1 NPK. The data after harvest of the groundnut revealed that soil properties like bulk density, pH, EC did not vary significantly. Organic carbon was recorded highest in organic farming, natural farming. Available macronutrients and secondary nutrients like nitrogen, phosphorus, potassium, exchangeable calcium and magnesium and sulphur were observed highest in POP. Dehydrogenase, phosphatase and urease activity was recorded significantly higher in organic farming. Nitrogen fractions like total nitrogen was recorded highest in organic farming. Available nitrogen, NH4+-N and NO3- -N were initially higher for farmer's practice but at later growth stages, it was higher for POP. Total nitrogen, available nitrogen, NH4+-N and NO3- -N were positively correlated with yield.