Effect of sowing dates and straw mulch on agroclimatic indices and photosynthetically active radiation interception in chickpea ( Cicer arietinum L. ) under terminal heat stress

Abstract Terminal heat stress poses a significant challenge to chickpea ( Cicer arietinum L.) production, necessitating effective strategies to enhance crop resilience. This study evaluated the impact of three sowing dates (1 November, 20 November and 10 December) and four paddy straw mulch levels (0, 2, 4 and 6 t/ha) on minimising terminal heat stress by improving agroclimatic indices, photosynthetically active radiation (PAR) interception and seed yield. Field experiments were conducted during the winter seasons of 2021–2022 and 2022–2023 at Punjab Agricultural University, Ludhiana, to assess agroclimatic indices such as growing degree days, helio-thermal units, photo-thermal units and pheno-thermal index along with PAR interception and yield attributes under different treatments. Results indicated that sowing on 1st November and application of 4 t/ha straw mulch significantly mitigated terminal heat stress by enhancing agroclimatic indices and PAR interception, leading to significantly higher yield attributes and yield. Although 6 t/ha mulch provided slightly higher benefits, they were marginal compared to 4 t/ha, making 4 t/ha the most practical and cost-effective choice. Lower mulch levels (0 and 2 t/ha) were less effective in alleviating heat stress impacts. Overall, early sowing (1st November) combined with 4 t/ha straw mulch was identified as the most effective strategy, minimising terminal heat stress and enhancing chickpea resilience and productivity. These findings emphasise the importance of timely sowing and optimised mulch application as practical, sustainable strategies for improving chickpea productivity under terminal heat stress.