Effect of Integrated Nutrient Management on Soil Fertility Status and Productivity of Rice-Maize Sequence Under Permanent Plot Experiment

Long term experiment (1988–2008) was carried out at Agricultural Research Station, Kathalagere, Karnataka to study the effect of integrated nutrient management on soil fertility status and productivity of rice-maize cropping sequence. The soil samples were collected after the harvest of summer maize crop in 2007–08 and analysed for pH, EC, organic carbon, available phosphorus and potassium status. The organic sources of nutrients in combination with inorganic fertilizers has showed improvement in organic carbon content from 0.68 per cent to 0.73 per cent, available phosphorus from 12.3 kg/ha to 22.01 kg/ha and maintained available potassium content. In general there was decrease in available potassium content among all the treatments due to crop removal as a result of continuous cropping. Significant increase in rice yield were noticed in treatments with paddy straw as source of nitrogen (25 to 50%). Higher maize yield was observed in treatments with both organic and inorganic fertilizers in kharif followed by 100 per cent NPK in summer season, thus showing the beneficial effect of organic sources of nutrients on the succeeding crop and also improving the soil fertility levels.