Ecology, Environment and Conservation Paper

EFFECT OF STRAW MULCH, IRRIGATION AND LAND CONFIGURATION ON SOIL HYDROTHERMAL REGIME UNDER BT COTTON (GOSSYPIUM HIRSUTUM L.)

Tonoy Kumar Das, Chandra Bhushan Singha and Raj Mukhopadhyay

Abstract

Crop diversification and water-saving techniques is necessary to control the ground water extraction in Punjab. Bt cotton offers a diversification option in this region. High soil evaporation and soil temperature during early part of the growing season are the bottle necks for Bt cotton cultivation. In this paper, we are addressing that straw mulching, bed configuration and irrigation can be the best management options to control such burning problems in Punjab soil. Keeping the above in mind, a field experiment was conducted at research farm of the Department of Soil Science, Punjab Agricultural University, Ludhiana, during kharif season in 2013 on sandy loam soil to study the effects of rice straw mulching, irrigation and land configuration on soil hydrothermal regime and total water use efficiency of Bt cotton. The treatments included three irrigation regimes viz., I1, I2 and I3 (on the basis of net cumulative PAN-E 212, 350 and 467 mm where the irrigation water input was 70 mm and 40 mm for flat and bed, respectively) in main plots, combination of two land configuration viz., bed-furrow and flat; two mulch rates viz., 0 (M0) and 6 t ha-1 (M6) in sub plots. Rice straw mulch lowered down the maximum and minimum soil temperatures at 5 cm depth by 1.9 to 6.9 °C and by 0.4 to 1.6 °C, respectively. The soil temperature amplitude narrowed down by 0.9 to 7.1 °C. Seasonal fluctuation in soil temperature was 9.2 °C under no mulched and 7.3 °C under mulched crop. Total water use efficiency found 0.69 kg ha-1 mm-1 higher under mulched plots. Bed-furrow configuration recorded 0.16 kg ha-1 mm-1 higher total water use efficiency than the flat configuration.