Agri-Brief: CONSIDER THE POTENTIAL OF STARTER THIS SPRING

AGRI-BRIEFS
AGRONOMIC NEWS ITEMS

From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335

Spring 2002, No. 7

CONSIDER THE POTENTIAL OF STARTER THIS SPRING

The benefits of starter fertilizer have long been recognized. Placement of phosphorus, potassium, and other nutrients in a concentrated band near the seed at planting often results in early season response that translates to yield increases and greater profit in the production of corn, grain sorghum, and other crops. A few of the potential benefits of starter are:

• Accelerated early plant development resulting in increased competition with weeds, decreased erosion due to quicker soil cover, and earlier harvest;

• Reduced grain moisture at harvest;

• Improved nutrient and water use efficiency;

• Increased yield and crop quality.

Several factors affect response to starter fertilizer. Soil conditions that increase the likelihood of starter response include cool temperature at planting and root growth restrictions such as compaction, acidity, salinity, and herbicide carryover. The response to starter phosphorus and potassium is expected to decrease as soil test levels increase. However, other factors like soil temperature or compaction may overshadow the effect of soil test level. In other words, the use of starter may be profitable where early cool, moist soil conditions prevail, even though soil test phosphorus and potassium levels are high.

Another important factor in considering the potential of starter fertilizer is residue level and degree of tillage. High levels of residue increase the potential of a profitable response to starter due to prolonged cool, wet spring soil conditions. Also, with reduced tillage, stratification of immobile nutrients such as phosphorus and potassium is increased, resulting in a greater potential for response to subsurface banding.

Recent research in Kansas has revealed that application of starter nitrogen, phosphorus, and potassium in a conservation tillage production system increased corn yields compared to a nitrogen only broadcast application in soils that were high in both phosphorus and potassium. At the irrigated location, 2x2 placement (2 inches to the side and 2 inches below the seed) of starter containing various combinations of nitrogen, phosphorus, and potassium resulted in an average corn yield increase of 44 bushels per acre in 2000. At the dryland site, the average increase due to 2x2 starter was 19 bushels per acre in 2000 and 2001. Increasing nitrogen rates above 20 pounds per acre in the starter did not result in further yield increases.

When starter is applied in a 2x2 placement the chance of injury and stand reduction from salt damage is negligible. However, where fertilizer is applied in-furrow with the seed, care should be taken to avoid seedling injury, stand reduction, and yield loss. The amount of fertilizer that can be used depends on fertilizer source, crop, row width, and soil moisture. For example, South Dakota State University recommends for corn in 30-inch rows no more than 10 pounds of nitrogen plus K₂O, up to 100 pounds per acre of material as 0-46-0 (triple superphosphate) and no urea or urea/ammonium nitrate combination.

The use of starter fertilizer is an effective management practice that is based on sound agronomic principles. So, as you make plans for the spring season, don’t overlook the potential benefits of a balanced starter fertilizer.

—WMS—

For more information, contact Dr. W.M. (Mike) Stewart, Great Plains Director, PPI, P.O. Box 6827, Lubbock, TX 79493. Phone: (806) 795-3252. E-mail: mstewart@ppi-far.org
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