Conducted by: Greg Roth, Doug Beegle, Mark Antle, and Shaun Heinbaugh
Location: Centre County, Pennsylvania
Sponsor: Pennsylvania Department of Agriculture
To evaluate differences in early growth, yield, and nutrient uptake using various liquid and dry starter fertilizers on high P testing soil.
Many forms of liquid and dry starter fertilizer are available and suitable for banding either in the row or at 2x2. Fertilizer material used for starter typically contains an increased amount of phosphorus to promote early season growth. As soil phosphorus levels increase, the need for additional phosphorus is debatable. Choosing between a liquid, dry, or no starter at all should depend on soil testing, equipment capabilities, price, handling ease and availability. Research shows that yields will be equal if a fertilizer with the same analysis is applied in either a liquid or dry form (Re hm, 1999).
In 2002, we repeated the starter formulation trial that was conducted in conjunction with the Farm Operations staff at Penn State in 2001. A field was selected that had Mehlich 3 soil test levels of 121 ppm P (high) and 232 ppm K (high), with a pH of 6.2 that had been previously in corn for grain. The treatments were designed to compare dry blends including standard 10-30- 10, and 16-8-8 starter fertilizers and AS and several AS based blends (16-8-8-16, 16-8-0-16) placed at 2x2 as well as three liquid pop-up fertilizers (9-18-9, 7-21-7, 7-17-3 Riser) applied in the row with the seed.
Soil samples and 20 plant samples were collected at the V6 stage of growth to determine early season growth as influenced by starter fertilizers. Standard nutrient analysis were run on the soil samples and the plant samples were analyzed for N, P, K, Zn, Ca, Mg, Cu, and B concentration. Included is a summary of early season growth as well as an evaluation of yield. Early season plant nutrient uptake was calculated using the plant analysis data and the V6 dry matter yields.
Differences in early growth were subtle and not statistically different, but there was a tendency for several treatments to have greater early season dry matter accumulation than the check (Table 1). These included the pop-up treatments, the 10-30-10 and the 16-8-8. Early growth results were very similar in 2001. Conditions for emergence and early season growth were good at this site.
The grain yield response to the starter fertilizers was mixed at this site (Table 1). Most of the 2x2 dry fertilizers tended to have higher yields than the check. Overall, the 2x2 treatments averaged about 2 bushels per acre higher than the check. There was a slight yield depression where ammonium sulfate or 16-8-8 was the starter. The pop-up treatments yielded slightly higher than the check by about 2 bushels per acre or 2% higher yields than the check. There were no significant differences among the pop-up fertilizer treatments. Overall the liquids and dry starter fertilizers yielded about 2% higher than the check; however no single treatment was statistically superior. During the growing season conditions were dry, especially during July and August.
Table 1. Dry matter (DM) yield at V6 growth stage and yield of corn as affected by nine different starter fertilizer programs on a high phosphorous testing soil in Centre County, Pennsylvania, in 2002.
|Treatment||Rate of Material/A|
|Rate of Material/A|
% of check
% of check
In general, differences in nutrient uptake at the V6 growth stage were small in this study. There were no treatments that significantly increased uptake when compared to the check (Table 2). Nitrogen uptake using pop- ups was increased about 14% over the check, while the dry starters averaged 3% lower than the check. Ironically, only 3 gal/A of each liquid was applied while 180 lbs/A of each dry fertilizer was used.
Table 2. Nutrient uptake of corn at V6 growth stage using nine different starter fertilizer programs on a high phosphorous testing soil in Centre County, Pennsylvania, in 2002.
These results are typical of what we have seen at high P testing sites. We have observed occasional early growth responses but generally no yield response to starters at P levels above about 75-100ppm. If producers want to use a starter, pop-up fertilizers seem to be a good alternative on sites like this. We saw a tendency for an increase in early season nitrogen uptake and they have seemed to yield as well as the dry starters provided early season N, P and K availability is good. Low application rates, low P rates and less handling of material also makes them attractive on high P testing soil.