Starter Fertilizers for Corn on Soils Testing High in Phosphorus in the Northeastern USA

Starter fertilizers with a high P analysis are commonly used in the northeastern USA for corn ( Zea mays L.) production, despite many soils testing above optimum (>50 mg P kg −1 ). The objective of this study was to evaluate responses to high P starter fertilizers in a band 5 cm from the row compared to alternatives such as banded higher N or conventional and low‐salt in‐furrow fertilizers. Two studies were conducted during 2000 through 2003 in Pennsylvania. The first study was a 3‐yr on‐farm study conducted to evaluate an untreated check, (NH 4 ) 2 SO 4 (AS), and 10–13–8.3 (N–P–K) as starters at 41 locations across Pennsylvania on high P testing soils. Early growth increased by 17% using 10–13–8.3 and 15% using AS compared to the check. Grain yields were 3.3% higher than the check for the AS treatment. Yields from the 10–13–8.3 were not different than the check but averaged 2.0% higher. A second 3‐yr study consisted of an untreated check, five banded granular starter fertilizer blends (10–13–8.3, 21–0‐0–24, 16–3.5–6.7–16, 16–3.5–6.7, and 16–0‐6.7–16) applied at 202 kg ha −1 , and three liquid in‐furrow treatments applied at 35 kg ha −1 (7–9.1–5.8, 7–7.4–2.5 and 7–7.8–7.5). Early growth and grain yield were significantly increased in 1 of 3 yr with some higher N starters. Eliminating starters, using higher N or in‐furrow starters on high P soils all appear to be possible management alternatives to high P starters.