Monitoring crop growth before and under center-pivot irrigation system using multi-temporal Landsat images

The small town of Eden is located in the Eden Valley in southwest Wyoming. This small community, located in a semi-arid high desert region, consists mainly of agriculture. Growers in the area produce primarily Alfalfa for livestock fodder. Due to the semi-arid climate and sandy soil conditions, salt runoff into the Colorado River through irrigation caused problems prior to the 1980's. The government established a program at this time to encourage Eden Valley farmers to change from flood to center pivot irrigation. Several growers did make the switch to center-pivot irrigation from flood irrigation system in order to minimize salt leaching from runoff waters as well as to conserve water. The research objective was to analyze the effect of the switch from flood to center pivot irrigation on crop growth through the use of Remote Sensing. Remote sensing has been used as a successful tool to analyze management practices in agricultural operations. Crop growth in a 140 acre of alfalfa grass mixture field in the Eden Valley was analyzed before (1984, 1985 and 1987) and after (1991-1993) the center-pivot irrigation system was installed. Landsat images acquired prior to the first harvest in these years were used to identify crop growth based on very high to very low vigor. This information was then used to compare the effect of center-pivot irrigation system on crop growth.