Irrigation Scheduling on Corn to Increase Profitability and Environmental Stewardship in Alabama.

The water shortage and the cost of irrigation are increasing the vulnerability of farmers for meeting crop water requirement. Thus, there is a need for new irrigation technologies and methods to increase water-use efficiency. The study was conducted at E.V. Smith research station (Shorter, AL) to evaluate the response of corn crops to irrigation and assess the performance of  Watermark sensors in the field. Therewith, we compared yield and water use considering two irrigation methods: Sensor Based Irrigation Method (Watermark) and Checkbook Method. We lead this research over two growing seasons (2014 and 2015). The field was divided into two management  zones delineated based on soil electrical conductivity data, soil texture, and soil survey analysis. Soil moisture sensors (Watermarks) were installed on both zones, four sensors per zone and 3 depths: 6, 12 and 24 inches to attain the corn root zone. The plots of every treatment were only irrigated when the soil moisture sensors installed at each zone reached a specific irrigation threshold of 35% depletion from plant available water, defined using the Soil Water Retention Curve. Then, we compared the amount of water applied using the Checkbook Method and the Sensor Based Method, once the irrigation trigger in each zone was reached in different frequency. The preliminary results of 2014 and 2015 indicated no significant corn yield differences between the irrigation scheduling treatments, however there were differences in the amount of irrigation water applied. In 2014 at zone A, lightest soil texture zone, on average Checkbook out yield Sensor Based Scheduling by 7 bu/ac but the checkbook used 5.4 inches of water more than the Sensor Based Irrigation Method.  At zone B, course textured zone, there were no yield differences but the checkbook used 4 inches of water more than the sensor based irrigation method.