Assessment of Soil Physico-chemical Properties in Direct Seeded Rice and Succeeding Lentil Crop under Integrated Nitrogen and Weed Management Practices in Eastern Uttar Pradesh, India

An experimentation was conducted during 2019-20 and 2020-21 at Banaras Hindu University, Varanasi, to evaluate the direct and residual effect of organic sources of nitrogen and weed management practices on various soil physico-chemical properties. The experiment was laid out in split plot arrangement having four nitrogen management treatments in main plot viz., Control (only P and K), RDF (150-60-60 kg ha-1 N-P2O5-K2O), 75% RDN (Inorganic) + 25% through FYM, 75% RDN (Inorganic) + 25% through Vermicompost and five weed management practices in subplots which consisted of Wheat residue as mulch (4 t ha-1) fb bispyribac Na 25 g a.i. ha-1 (2-4 leaf stage of weed), Pendimethalin 1 kg a.i. ha-1fb bispyribac Na 25 g a.i. ha-1 (2-4 leaf stage of weed), Sesbenia up to 30 days (Brown manuring), Two hand weeding (20 and 40 DAS) and Weedy check and replicated thrice. Results indicated that application of 25% nitrogen through farmyard manure in combination with 75% nitrogen through urea being at par with 75% RDN (Inorganic) + 25% through Vermicompost, brought significant improvement in soil chemical properties (electrical conductivity and pH) but physical property i.e., Bulk density did not turn significant after harvest of direct seeded rice. The treatment also recorded significantly maximum available soil nitrogen, phosphorus and potassium compared to 100% nitrogen through urea and control treatment though remained comparable with 25% nitrogen through vermicompost along with 75% nitrogen through urea during both years. Whereas, in respect to the residual effect of organic sources, improvement in soil properties after harvest of succeeding residual lentil crop was observed, but failed to touch the level of significance in either year of study. Among weed management practices, maximum improvement in soil physicochemical properties was noticed with the use of Sesbania brown manuring for both years after harvest of rice as well as after harvest of succeeding lentil crop but the differences could not reach up to the level of significance.