5 pages, We developed an Excel-based computational template Extension educators can use to assist clientele with scheduling irrigation for efficient use of water. With the template, the user applies the dual crop coefficient method to calculate evaporation and transpiration rates separately, with the result being more accurate soil water tracking as compared to what occurs when a single crop coefficient is used. Crop water needs can be conveniently calculated on the basis of soil characteristics, crop growth stages, and weather information. Application examples demonstrate that the amount and frequency of irrigation should be adjusted according to soil texture. The template and application examples are available to Extension professionals as electronic supplementary material.
7pgs, Aerial images taken during the growing seasons of 2009, 2011, 2013, 2015, and 2017 were visually inspected for evidence of irrigation. Center pivot irrigation was identified by the characteristic shape of the spans and the curved tracks left by the wheels. The author manually delineated a polygon over each agricultural area where signs of irrigation infrastructure were observed. The result is a map of 2,689 polygons covering 146,662 acres in South Carolina. Compared with the United States Department of Agriculture 2017 Census of Agriculture, the sampling results account for over 69% of total irrigated area and over 98% of area irrigated solely by center pivots. Most center pivots covered from 25 to 75 acres, while the largest center pivot extended over 300 acres. These results are an important contribution to the quantification of water use in South Carolina.
