Agronomist studying irrigation relationship to costs and environment

As efficient use of nutrients and water becomes an increasingly hot topic in agriculture, LSU AgCenter agronomist Syam Dodla is examining ways to lower production costs and minimize environmental impact without negatively affecting crop health or yields.
Dodla is part of a new team at the AgCenter's Red River Research Station that helps Louisiana producers manage irrigation systems and maintain good water quality. In addition to Dodla, the group includes an irrigation engineer, an economist and a water quality expert.
Dodla, who received his doctorate in agronomy from LSU in 2009, said many Louisiana farmers use traditional irrigation methods, such as furrow irrigation, that waste a significant amount of water and cause farm chemicals to run off into waterways.
While cutting back on the amount of water used for irrigation can save money and reduce waste, it is critical that farmers know exactly how much water their crops need to grow properly. Dodla said technologies like automated soil moisture sensors that monitor how much water is being used and how often can help.
Irrigation frequency and amount affects other factors like how much fertilizer must be applied and which types work best with more or less water. Dodla hopes to identify how much fertilizer and water is optimal in terms of cost, crop quality and efficiency.
Dodla said it is important for producers to address these issues on their farms now because water tables, especially in northern Louisiana, are being depleted and becoming increasingly saline. When farmers use furrow irrigation, they not only use a lot of water — they also add excess salt to their soil, which increases soil pH, he said.
"In the long-term, the soil becomes less fertile," Dodla said. "Also, when you use furrow irrigation, you are spreading a lot of water that carries away highly fertile topsoil, so you may need to use more fertilizers. That causes more nutrients to get into groundwater or surface water, which can create environmental and health issues."