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A field experiment was conducted for two years in “Deep Black Soils” to study the residual and direct effect on growth, yield, monetary efficiency, nutrient uptake and soil properties after harvest...

Background: Intensive rice cultivation for longer periods continuously resulted in poor soil fertility. Inorganic fertilizers along with integrated and judicious use of different organic sources like FYM, vermicompost, green manure etc. could be an effective choice for enhancing crop yield. A synergistic effect on crop yield is reported through common use of fertilizer and organics which also improve soil fertility. The residual effects of organic manures applied to the preceding crops can be available to succeeding crop. Therefore, this experiments was planned to throw light on the use integrated nutrients through organic and inorganic sources on rice and its residual effect on succeeding greengram. Methods: A field experiment was conducted to study the effect of integrated nutrient management on rice-greengram cropping sequence at Navsari Agricultural University, Gujarat during 2012-15. Five nutrient combinations were evaluated in randomized block design for rice and its residual effect on productivity on succeeding greengram was studied with three fertilizer levels in split plot design. Result: Application of general recommended dose of fertilizers (RDF) to rice has increased growth, yield, quality, economics and improved soil properties and the residual effect to succeeding greengram have also gave significantly higher greengram seed yield and other important parameters and this was succeeded by application of 75% RDF through chemical fertilizer + 25% RDF through vermicompost. Among different levels of fertilizers to greengram, application of 100% RDF gave highest greengram seed yield, economics and soil parameters over other two levels.

A field experiment was conducted during Kharif seasons of 2014, 2015 and 2016 with an objective to assess the feasibility of weed and nutrient management in direct-seeded rice. The experiment was laid out in a factorial RBD with eighteen treatment combinations including six weed management treatments, viz. pretilachlor, pendimethalin, pretilachlor followed by (fb) bispyribac-sodium, pendimethalin fb bispyribac-sodium, weed free and weedy check and three nitrogen (N) levels, viz. 80, 100 and 120 kg N/ha with three replications. Significantly lower weed biomass was recorded with weed free which [2 hand weedings (HW) at 20 and 40 days after seeding (DAS)] was at par with pendimethalin 1.0 kg/ha pre-emergence treatment (PE) fb bispyribac-sodium 0.04 kg/ha, post-emergence treatment (PoE). Similarly, the highest weed control efficiency (WCE, 73.0%) and the lowest weed index (WI) were also recorded with weed free treatment, followed by pendimethalin 1.0 kg/ha fb bispyribac sodium 0.04 kg/ha (WCE, 71.2%). Rice growth and yield attributes, viz. plant height, effective tillers, panicles length, grains/panicle were improved significantly under combine application of PE and PoE herbicides either pendimethalin 1.0 kg/ha or pretilachlor 0.75 kg/ha (PE) fb bispyribac 0.04 kg/ha (PoE) and weed free [2 HW at 20 and 40 DAS]. Further, weed free treatment as well as pendimethalin 1.0 kg/ha fb bispyribac 0.04 kg/ha were found equally effective and recorded significantly higher rice grain and straw yield and nutrient use efficiency (NUE) with higher net returns compared to rest of treatments. Application of 120 kg N/ha significantly increased the plant height, effective tillers/plant, panicle length, grain/panicle, grain and straw yield, N content and NUE % over rest of the treatments in all aspects of yield and yield attributes. It was concluded that 2 HW at 20 and 40 DAS or application of pendimethalin 1.0 kg/ha fb bispyribac-Na 0.04 kg/ha for weed control appeared to be a viable strategy along with 120 kg N/ha for achieving higher and profitable yield of direct-seeded rice.

An experiment was conducted at the Instructional Farm, Navsari Agricultural University, Navsari (Gujarat) during kharif seasons of 2012 and 2013 on transplanted rice under rice-greengram cropping sequence in randomized block design with five treatments replicated four times. The treatment imparted to rice crop was integrated nutrient management viz., T1-General RDF (RDF: 100-30-00 kg N-P-K/ha+FYM @ 10 t/ha), T2-75% RDN through chemical fertilizer+25% RDN through biocompost, T3-75% RDN through chemical fertilizer+25% RDN through vermicompost, T4-75% RDN through chemical fertilizer+25% RDN through FYM and T5-Control. On the basis of pooled mean, the results indicated that application of general RDF (RDF+FYM @ 10 t/ha) recorded significantly highest grain and straw yields of rice as well as total NPK uptake by rice (grain and straw) than other treatments followed by 75% RDN through chemical fertilizer+25% RDN through vermicompost. However, maximum net returns and benefit ratio were noted with the application of 75% RDN through chemical fertilizer+25% RDN through biocompost followed by general RDF (RDF+FYM @ 10 t/ha).