Soybean Root Growth and Yield Response to Variable Rate Irrigation

Abstract

A changing climate and an increasing world population result in a greater need of food. Water secures and increases yield. However, water use and irrigation timing need to be optimized to limit negative effects on natural resources. The objectives of this project are to determine how irrigation affects soybean root development through minirhizotron observation and evaluate yield performance of soybean cultivars under different irrigation regimes. In 2016, a first experiment with 5 irrigation treatments (0.0cm, 0.9cm, 1.9cm, 2.9cm, 3.8cm) and 8 cultivars indicated different responses of cultivars to irrigation. In 2017, the experiment was repeated with 6 irrigation treatments (dryland, checkbook, sensor, R3, R5, R3+R5) and 6 cultivars and indicated different responses of cultivars to irrigation. In 2016, yield response showed significance between cultivar and irrigation. 2016 soybean root growth found no significance between treatment, replicate, or depth. In 2017, yield response showed no significant interactions and 2017 root growth found no interactions between treatment, replicate, or depth. Minirhizotron field research is limited in that data can only be collected from the area surrounding the minirhizotron tube. In regard to yield, response showed significance between cultivar and irrigation during 2016 and no significant interactions in the growing season of 2017. These differences in findings can most likely be attributed to disparities in rainfall during the two growing seasons where 2016 was classified as a dry year and 2017 was classified as a normal year of rainfall.