Response of Crop Growth Rate and Absolute Growth Rate of Late-Sown Chickpea (Cicer arietinum L.) to Nutrient and Weed Management

Abstract

A field experiment was conducted during the rabi seasons of 2022-23 and 2023-24 at the Agricultural Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, to evaluate the effect of integrated nutrient and weed management on crop growth rate (CGR) and absolute growth rate (AGR) of chickpea. The experiment was laid out in a split-plot design with three replications, comprising four nutrient management practices viz., F0-control, F1-100% recommended dose of fertilizers (RDF), F2-75% RDF + Rhizobium + phosphate-solubilising bacteria (PSB) and F3-50% RDF + Rhizobium + PSB + molybdenum seed treatment + foliar boron and urea spray and eight weed management practices viz., W1-pendimethalin (PE), W2-quizalofop-p-ethyl (PoE), W3-topramezone (EPoE), W4-pendimethalin followed by one hand weeding (25 days after sowing), W5-pendimethalin followed by quizalofop-p-ethyl, W6-pendimethalin followed by topramezone, W7-weedy check and W8-weed-free. The results revealed that nutrient and weed management significantly influenced crop growth throughout the crop growth period. The application of 100% recommended dose of fertilizers (RDF) recorded the highest CGR (4.36, 5.79, 7.96 and 7.99 g m-2 day-1) and AGR (0.154, 0.205, 0.282 and 0.291 g plant-1 day-1) during 30-60 and 60-90 days after sowing (DAS) in 2022-23 and 2023-24, respectively, followed by 75% RDF combined with Rhizobium and phosphate-solubilising bacteria (PSB), whereas the unfertilised control recorded significantly lower values. Among weed management practices, pendimethalin (1.0 kg a.i. ha-1) applied as pre-emergence followed by one hand weeding at 25 DAS (W4) recorded significantly higher CGR and AGR than the remaining herbicidal treatments and was closely comparable with pendimethalin followed by topramezone (W6), indicating that sequential weed management effectively minimised crop-weed competition and promoted biomass accumulation. Absolute growth rate declined progressively with crop age irrespective of treatments, reflecting the normal ontogenic reduction in growth efficiency. The study demonstrated that balanced nutrient management combined with effective weed management substantially improved crop growth by enhancing dry matter accumulation and resource-use efficiency. Under late-sown conditions, the application of 100% RDF in combination with pendimethalin followed by one hand weeding or pendimethalin followed by topramezone proved to be the most effective management strategy for maximising chickpea growth.