Radiation interception, extinction coefficient of radiation and leaf area index of wheat under open and poplar plantation

Abstract

The study was conducted during the rabi season of 2023-24 at the Research Farms of the Department of Climate Change and Agricultural Meteorology and the Department of Forestry and Natural Resources, Punjab Agricultural University, Ludhiana. The experiment was laid out with split plot design incorporating three sowing dates (20^th October, 5^th November and 20^th November) in main plots and three wheat varieties (PBW 826, HD 3086 and PBW 677) were included in the sub plots and was replicated thrice. The photosynthetically active radiation (PAR) and leaf area index were monitored at regular intervals in both growing environments at different phenological stages. PAR interception remained higher under open conditions by 20-29%, than under poplar plantation. The leaf area index was consistently recorded highest in first sowing, under both open (4.45) and poplar plantations (4.19). Among the varieties, PBW 826 exhibited the highest LAI, with 4.65 in open conditions and 4.38 under poplar plantations, outperforming HD 3086 and PBW 677 across all conditions. The extinction coeffecicient (k) was maximum (0.60, 0.45) at anthesis and hard dough stage in first date of sowing followed by second and third date of sowing. Among varieties k value was maximum (0.58,0.41) in variety PBW 826 followed by HD 3086 and PBW 677 at both growth stages. The k value was comparatively lower under poplar plantation at both phenological stages in different treatments. The relationship developed between PAR interception and LAI under both environments exhibited significant R2 value (0.77 & 0.92).