The influence of transgenic ( Bt) and non-transgenic (non- Bt) cotton mulches on weed dynamics, soil properties and productivity of different winter crops

Abstract

The introduction of transgenic cotton ( Bt-cotton) for controlling bollworms has resulted in increased production; however, the residual effects of mulches from Bt-cotton are poorly understood. Therefore, the current study evaluated the impact of Bt and non- Bt cotton mulches on soil properties, weed dynamics and yield of winter crops sown after cotton. Three different winter crops, i.e., wheat ( Triticum aestivum L.), canola ( Brassica napus L.) and Egyptian clover ( Trifolium alexandrinum L.) and two mulch types, i.e., Bt mulch (obtained from Bt-cotton cultivars, i.e., ‘CIM-616’ and ‘GH-Mubarik’) and non- Bt mulch (obtained from non- Bt cultivars, i.e., ‘CIM-620’ and ‘N-414’) were included in the study. The mulches were applied at a rate of 2 t ha ^-1 before planting the winter crops. The Bt and non- Bt mulches differentially affected soil properties, weed dynamics and productivity of winter crops. The non- Bt mulches decreased the soil bulk density and penetration resistance, while increased the soil porosity. Wheat crop increased the soil porosity, pH, available N and soil organic matter content. Overall, non- Bt mulches improved the productivity of winter crops compared with Bt mulches. The toxins released by Bt mulches lowered the weed density; however, it negatively influenced soil properties (bulk density and available nitrogen) and productivity of winter crops. Therefore, appropriate crop rotation measures may be opted for the soils cultivated with Bt-cotton to conserve soil and achieve yield sustainability for the crops sown after cotton. Nonetheless, non- Bt mulches can be used for improving soil properties and productivity of winter crops.