Efficient soil solarization for weed control in the rain-fed upland rice ecosystem
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1
Land, Water, Environment & Engineering Research Programme, ICAR Research Complex for Eastern Region
2
Water Technology Centre for Eastern Region (ICAR), Bhubaneswar 751 023, India
3
Central Research Institute for Jute & Allied Fibre (ICAR), Barrackpore 743 101, West Bengal, India
4
Vice- Chancellor, Rajendra Agricultural University, Pusa, Samastipur 848 125, Bihar, India
Int. Agrophys. 2003, 17(3): 99-103
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ABSTRACT
Weed competition causes significant damage (up to 90%) to crop yields. Weed control through chemical means in the form of herbicide is commonly used to kill weeds or inhibit their growth throughout the world. However, the use of herbicides has increased toxic residues dangerously, indiscriminately targeting organisms, the environment, and ground water and creating serious upheaval in the ecosystem. Studies were conducted through a series of experiments for five consecutive wet seasons with a variety of alternative biological solutions to control the weeds. These solutions are benign, harmless, pollution free, non - hazardous and eco - friendly and control the pre-emergence of weeds in the rain-fed, upland rice ecosystem whereas in the high rainfall coastal region of eastern India, control was effected through soil solarization. This is a method of heating the soil's surface by using transparent low-density polyethylene (LDPE film) sheets placed on the soil's surface to trap solar radiation. This raises the soil temperature to a level which is lethal for many soil borne pathogens and weed seeds, thus killing weeds before they even begin to grow.
The rise in soil temperature due to solarization by using LDPE film was significantly correlated to the soil temperature under normal conditions (uncovered) and the cumulative solar radiation (Wm-2) of that day but the effect of the air temperature was found to be insignificant. A quadratic relationship was developed between temperature difference (DT) and soil temperature (ST) and the cumulative solar radiation (SR) for that day. The use of transparent and black LDPE sheets reduces weed growth and increases rice yield. Higher yields were found in treatments using transparent LDPE films of 200 gauges and 400 gauges for 30 days followed by black LDPE film. However, lower yields were recorded from the fields which were covered with LDPE films (both 200 and 400 gauge) beyond 30 days.