Bruce Schultz, Blanchard, Tobie M., Gould, Frances I.
Syam Dodla, LSU AgCenter agronomist, at a corn plot at the Red River Research Station. He is studying split fertilizer applications on no-till corn. Photo by Bruce Schultz
Syam Dodla, LSU AgCenter agronomist, is studying fertilization rates in no-till fields for corn and soybeans.
“Compared to conventionally tilled soils, soils in no-till fields have different structure and properties with varying amounts of nutrients found in layers of the soil profile,” he said.
No-till systems have higher soil organic matter content and microbial population.
Dodla said some studies have shown 20 percent more nitrogen is needed for optimum field corn production for the first few years of no-till production. Current LSU AgCenter fertilizer recommendations are based on many years of fertilizer trials in conventional tillage systems and lack nutrient recommendations for no-till systems.
Dodla is currently studying split applications of nitrogen for corn, comparing the results with a single application, in addition to comparing liquid and solid nitrogen fertilizers at two rates (200 pounds per acre versus 240 pounds per acre) for no-till systems.
Dodla is testing corn nitrogen fertilizer applications at three different timings: 100 percent at 2-leaf stage; 25 percent at 2-leaf stage, 75 percent at the 6-to-7-leaf stage; and 25 percent at 2-leaf stage, 50 percent at 6-to-7-leaf stage and 25 percent at tasseling. The same study is also replicated under conventional tillage system and in two soil types (clay and sandy loam soils) to develop optimum nitrogen management for corn in no-till systems with different soil types.
Another test involves planting soybeans after cotton, comparing no-till and conventional tillage.
Dodla said the no-till plots have been slower to develop, especially in clay soils, probably because of the relatively compacted topsoil compared to tilled soils.
He is looking at the phosphorus and potassium fertilization rates for no-till soybeans. The study evaluates use of granular fertilizer versus liquid fertilizers and application rates. In addition, Dodla wants to see if soybeans in a no-till field would benefit from a booster application of nitrogen at planting.
Dodla said soil compaction associated with no-till is reduced by including winter cover crops.
Weed management is simpler under cover crops compared to fallow ground that minimizes weed issues during main crop. Incorporating legume cover crops also helps add nitrogen to the soil, he said.
The LSU AgCenter and the LSU College of Agriculture