Assessment of PAR Interception and Radiation Use Efficiency on Tomato Growth and Yield in the Upper Brahmaputra Valley Zone of Assam, India

A field experiment was conducted in Jorhat, Assam during the rabi season of 2019-20 to examine the effects of PAR interception, radiation use efficiency, and modified microclimates on tomato growth and yield. The variety Arka Rakshak was grown in split plot design with 4 dates of planting (P1: 25th October, P2: 14th November, P3: 3rd December, and P4: 8th January) in main plots and three types of mulching (M0: no mulch, M1: rice straw mulch, and M2: black polythene mulch) in sub-plots. Measurements of incident PAR (IPAR), reflected PAR (RPAR), transmitted PAR (TPAR) were taken at 10 days regular intervals. The results showed that IPAR ranged from 531 to 1431 μ mol s-1 m-2, with an average of 1140.4 μ mol s-1 m-2. RPAR varied between 41 and 285 μ mol m-2 s-1 under different microclimates. The tomato yield ranged from 76.6 to 392.6 q ha-1, with an average of 234.9 q ha-1. Planting on November 14th (P2) provided the most favorable microclimate conditions, while black polythene mulch (M2) was found to be the most suitable for crop growth, yield, and radiation use efficiency due to increased soil temperature. The study indicated that selecting the right planting date and implementing black polythene mulch can enhance tomato growth, yield, and radiation use efficiency in Upper Brahmaputra Valley Zone of Assam (Jorhat) agro-climatic condition.