AGRONOMIC NEWS ITEMS
From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335
Spring 2001, No. 4
“I’ve got too many acres to plant to mess with starter.” This statement reflects the trend toward larger farms. In the spring, farmers are concerned primarily with the logistics of getting all of their acres covered as quickly as possible. Research has shown that delayed planting can lead to yield losses. Spring carries a high probability of rainy, cool weather. So when the window of opportunity opens, the last thing any farmer wants is an increased risk of not getting the seed in the ground. But there’s another risk that many forget. Cool, wet conditions increase the risk that nutrient supply to the plant will be limited. In such environmental conditions, slowdowns occur in nutrient absorption by the roots, carbohydrate translocation to the roots, and nutrient transport to the roots. All of these slowdowns increase the risk of reductions in yield potential. So cool, wet conditions increase the farmer’s desire to plant quickly, but also increase the chance that starter will provide benefits.
“Starters can make the corn look better early, but they normally don’t translate to yield.” The application of starter fertilizer can hasten the maturity of the corn crop. This is often demonstrated by increased plant height and greater generation of biomass early in the season. But growth and development differences early in the season may not result in economic responses. So what conditions increase the chances that starter fertilization will actually be advantageous? There are two primary benefits that have been identified: increased yield and decreased grain moisture. Lower grain moisture may be especially important this year to save on drying costs during high natural gas prices. The probability of seeing such benefits increases whenever the plant’s demand for nutrients becomes greater than the root system’s ability to supply them, such as 1) cold, wet soils, 2) reduced tillage systems, 3) compacted soils, 4) soils low in nutrients, 5) areas with detrimental herbicide carryover, 6) high soil salinity, and 7) high soil acidity. Under such conditions, observed early growth has greater chances of providing end of season yield and moisture benefits.
“Corn planted later won’t benefit from starters.” Many believe that once soils warm and become drier that starters won’t provide much benefit. However, in northern areas of the Corn Belt, the growing season is short enough that hastened maturity from starters becomes an important issue. Research from Wisconsin has shown that both planting date and the relative maturity of the hybrid are important factors. The probability of getting both yield and moisture benefits from starter fertilization increases steadily for longer season hybrids planted later. Late planting increases the risk that the season will be too short and cut into yield potential. This risk increases for longer season hybrids. Applying starter reduces these risks when longer season hybrids are planted later.
Starter fertilization is an important management option. Understanding your cropping system, soils, environmental conditions, and soil fertility are important for making the right decision. It is important that in the rush to get corn planted we not dismiss too readily the potential benefits of starter fertilization.