Temporal and Spatial Variation Analysis of Water Requirement of Tobacco in Middle of Yunnan Province Based on Irrigation Requirement Index

Abstract:

Spatio-temporal variation of crop water requirement and net irrigation requirement can provide theoretical basis for irrigation scheduling in different areas. The research was based on ground meteorological data from four national meteorological sites and crop coefficient at different growth stages of tobacco in the middle of Yunnan Province. The reference crop evapotranspiration, net irrigation requirement and net irrigation requirement index in the middle of Yunnan Province within 58 years (1956—2013) were calculated using the Penman—Monteith equation recommended by Food and Agriculture Organization in 1998. The water demand variation characteristics of tobacco during the growing season were analyzed. The spatial analysis of water demand, net irrigation requirement and net irrigation requirement index of tobacco was done by using the ordinary Kringing method of GIS. The results showed that as the change of tobacco’s growing season, its net irrigation requirement index was gradually decreased. And the years with net irrigation requirement index which was larger than zero could be accounted for about 54% in the middle of Yunnan Province. It was indicated that tobacco needed artificial irrigation in normal years. The most positive and negative correlation factors for net irrigation requirement of tobacco was precipitation. Besides, the reference crop evapotranspiration, net irrigation requirement and net irrigation requirement index increased with latitude in the middle of Yunnan Province.