Optimal Irrigation Scheduling for Summer Maize Crop: Based on GIS and CROPWAT Application in Hetao District; Inner Mongolia Autonomous Region, China

摘要

Net Irrigation Water Requirement was estimated using GIS and CROPWAT software. The study aims to develop an optimal irrigation scheduling in summer, to increase crop yield under water scarcity conditions. The proportion of rainwater evaporated over year 2008 “868.6 mm/dec” was used to compare with the water requirements of the maize crop “734.1 mm/dec” The results showed deficits ranging between 30.7 mm/month and 200.8 mm/month, for the period between April and September. In addition, there was uneven distribution of precipitation and an irregular basis during the agricultural year (2000-2008). The ET 0 was between 0.47mm and 3.08mm, and net irrigation water requirement was 833.4 mm for the maize crop. On refilling soil to field capacity with irrigation at critical depletion, 70% field efficiency was achieved which correspond to optimal condition, while adapting fixed interval per stage gave a yield reduction of about 2.5 %.