Influence of long-term organic and inorganic nutrient inputs on soil chemical properties across depths in calcareous soils

The long-term impact of chemical fertilizers on soils and environment is harmful. Use of unbalanced nutrients in the soils may be harmful in the long run causing soils an unproductive one. It is true that sustainable production of crops cannot be maintained by using only chemical fertilizers and similarly it is not possible to obtain higher crop yield by using organic manure alone. Proper identification and management of soil fertility problems are prerequisite for boosting crop production and sustaining higher yields over a long period of time. So, use of organic manure in integration with inorganic fertilizers is very important in improving soil fertility and crop productivity. In order to study the long-term effect of organic and inorganic fertilizers on soil chemical properties of soil under rice-wheat cropping system in Bihar region a field experiment was conducted at in an on-going (since 1988-1989) long term effect of crop residue management on fertilizer economy and soil fertility (STCR) under the programme ‘All India Co-ordinated Research Project on soil test crop response correlation (AICRP-STCR)’ at Dr. Rajendra Prasad Central Agricultural University Pusa, Samastipur (Bihar), India. The application of NPK along with organic residues increased the pH, EC, organic carbon. The content of available N and P₂O₅, K₂O improved significantly over the control. The content of N and P₂O₅, K₂O ranged from 134 to 416 kg ha-1 and 13.9 to 27.8 kg ha-1,115 to 225 kg ha-1 respectively at the surface layer and 149 to 357 kg ha-1 and 10.9 to 22 kg ha-1, 97 to 150 kg ha-1 respectively at the sub-surface layer.