Growers can expect bonuses with no-till cotton yields by using starter fertilizer at planting, says Donald Howard, University of Tennessee soil scientist.
Howard has been evaluating in-furrow application of starter fertilizers since 1983. He's found that they're particularly effective in the cool, wet soil conditions typical of no-till production.
Conventional wisdom says starter should be applied 2 x 2 (2" to the side and 2" below the seed). But for highly erosive soils, Howard recommends in-furrow placement for several reasons. More equipment is needed for 2 x 2 - generally an extra set of coulters and knives, an extra toolbar and more tractor horsepower.
Howard says in-furrow applications are simple.
"Attach an orifice or spray nozzle to a bracket located at the back of the planter shoe to apply liquids. You can use the same bracket used for insecticides or fungicides," he says.
"In-furrow applications reduce the number of soil slits and the potential for erosion. Both liquid and dry starter materials are effective, but I prefer liquids because they're more convenient."
The fertilizer program in his no-till research uses N, P2O5, K2O, and K2O plus Ca (NO3)2 as the starter. Starter rates ranged from 2 to 8 lbs N/acre.
Howard says these rates are safe, but growers need to "calibrate, calibrate, calibrate. The strategy is to apply a small but sufficient nutrient rate that will not require extra stops to fill the fertilizer hoppers or tanks and slow down planting."
In-furrow applications of medium to high NH4+ may reduce cotton germination. The effect is a temporary calcium deficiency. The calcium nitrate eliminates this problem. Howard advises growers to clean the application system before using calcium nitrate, particularly if liquid phosphate fertilizers have been used in the equipment.
"The economic advantages to the grower are obvious. But we anticipate that, in the future, restrictions and regulations may limit fertilizer applications for crop production," Howard ex- plains. "Our objective with an in-furrow starter program is to maintain yields with fewer in- puts. That not only helps profitability, but conserves resources and protects the environment."