Optical properties of plastic mulches affects weed populations

Abstract

The effect of plastic mulch on soil temperature, mulch surface temperature and the radiation balance is determined primarily by the optical properties of the material. Mulches may transmit, absorb, or reflect a portion of the incident radiation at each wavelength. The mulches decrease light transmission and prevent development of most weed species. Laboratory and field experiments were conducted to measure optical properties of different plastic mulches and evaluated owing to its light transmission in terms of weed infestation during the year 2017 and 2018. The unused plastic mulches were silver-on-black, black and transparent. On average, 83.01%, 57.28% and 43.61% light in the 400 to 1100 nm range was transmitted through the transparent, black and silver-on-black plastic mulches, respectively. After 120 days of field exposure (used) different plastic mulches on average 85.36%, 42.65% and 34.93% light in the 400 to 1100 nm range was transmitted through the transparent, black and silver-on-black plastic mulches, respectively. Different plastic mulches were evaluated owing to its light transmission in terms of weed infestation and results revealed that weed infestation was observed highest in transparent plastic mulch and negligible in silver-black plastic mulch. Highest weed density and total weed biomass 152.33 No./m2 and 129.19 g/m2, respectively were observed in transparent plastic mulch, whereas total absence of weeds were observed in black plastic mulch.