Tuesday, November 14, 2006 - 2:00 PM
157-3
Crop Management Zones Agronomic and Economic Successes.
Rajiv Khosla and Dwayne Westfall. C013 Plant Sciences Bldg., Dept. of Soil & Crop Sci-CSU, Dept. of Soil & Crop Sci-CSU, Fort Collins, CO 80523-1170, United States of America
Management zones were formally introduced as a means to manage in-field spatial variability nearly a decade ago. Several methods of management zone delineation have been proposed and researched throughout the United States United States Colorado State University initiated a large-scale multidiscipline precision agriculture project in 1997. Research sites were located on several large-scale production irrigated maize fields in Eastern Colorado. Fields were divided into management zones based on bare-soil color. Fields were managed using both traditional uniform N application and a management zones approach. Several parameters were measured and compared between management including: grain yield, biomass, N uptake, N-use efficiency, soil texture, soil organic matter, soil bulk density, and economic returns. Management zones based on bare-soil were found to be significantly different with regard to soil physical properties (soil texture, bulk density, and organic matter). Grain yields and N uptake from irrigated maize fields were also found to be consistently different between management zones. When comparisons were made between traditional uniform N applications and variable N applications based on soil-color based management zones, the variable N application based on site-specific management zones were found to be more economically efficient than the uniform N application strategies. Overall, research conducted over the last seven years indicates that bare-soil management zones are agronomically effective and economically viable means of increase nitrogen-use efficiency.