Effect of Integrated Nutrient Supply on Yield, Nutrient Uptake and Soil properties in Rice-Rice Crop Sequence on a Vertic Haplustepts of South Gujarat

摘要

A field experiment was conducted with rice-rice cropping sequence for seven consecutive years (from 1999 to 2006) on a Vertic Haplustepts. Twelve treatments comprised of 50 to 100% of recommended dose of fertilizer (RDF) to both kharifand summer cropsapplied alone and in combination with P solubilizing bacteria (PSB), crop residues, FYM, or pressmud or with biocompost. In one treatment N, P and K were applied as per soil test value to both the crops. The treatment receiving N, P and K, as per soil test yielded at par with treatments of RDF, RON and 50 % P with PSB to both the crops, RDF + crop residues @ 5 t ha~(-1) to both the crops and RDF + 50 kg K ha~(-1) to both the crops. The treatments receiving organics alongwith inorganic sources showed lower values. The effect of different treatments was significant on the uptake of N, P, K, Zn and Fe and was maximum in either RDF + 50 kg K ha~(-1) to both the crops (kharifand summer) or N, P, K as per soil test to both the crops, remaining at par with RDF to both the crops and RDN + 50 % RDP +PSB to both crops. Application of PSB was effective when applied with inorganic P, while application of organic manures did not show significance on uptake. The only S uptake varied significantly during summer. Atthe end of 7th crop sequence, soil quality status improved upon initial status with indication of significantly lower bulk density, higher organic carbon, available N, P and K, heat soluble S and DTPA-extractable Fe and Zn and water stable aggregates (>1.0 mm) in the treatments receiving either of the organics in combination with inorganic fertilizers. Though inorganic fertilizer showed its superiority with respect to sequential (kharif + summer) higher rice yield, from soil health sustainability pointof view integrated nutrient system performed better than inorganic fertilizers.