Modified self-moving irrigation system for water-nitrogen crop production studies

A lateral move irrigation system was modified so that controlled quantities of water and nitrogen could be applied to field plots. The system was designed to be mobile so that it could irrigate crops in several fields that were grown using different cultural management practices. The system design can be extended from studies of irrigation scheduling to varying the depth of water applied. The number of spray lines could be increased or the nozzle arrangement varied to give different treatment effects. A technique was developed to verify the system flow rate and nitrogen injection rate using a nitrate specific ion electrode. A central composite rotatable statistical design was used to reduce the number of plots required without reducing the plot size to obtain meaningful data and minimize experimental resources. Data collected from these plots can be used to predict water-nitrogen response surfaces of the quadratic form.