The higher Bt cotton acreage and output will partially compensate the overall decline in cotton acreage and output in North India in 2008-09 (October-September), O P Agarwal, executive director, Cotton Association of India, said today. Lack of irrigation in Ganganagar cotton belt in Rajasthan led to a 35 per cent fall in cotton acreage from 368,000 hectares in 2007-08.