No‐Till Row Crop Response to Starter Fertilizer in Eastern Nebraska: I. Irrigated and Rainfed Corn

Abstract

Early corn (Zea mays L.) growth is often slowed by cool soil temperatures in no‐till production systems. This inhibitory effect may be reduced through use of starter fertilizer and result in increased grain yield, but research findings have been inconsistent. Field research was conducted in four counties of eastern Nebraska to determine the probability and magnitude of corn response to starter fertilizer under varying field conditions for different combinations of nutrients and placement methods. Soils at trial sites included Typic Eutrudepts, Udic Ustorthents, and several Mollisols. Placements of N + P and N + P + S in‐furrow, over‐the‐row, and 50×50 mm were compared for effects on early growth and grain yield. Early growth was increased with starter fertilizer by 30% over all irrigated trials and by 10% for three of five responsive rainfed trials. In the irrigated trials, starter fertilizer increased grain yield by 0.86 Mg ha−1. Starter fertilizer had a minimal effect on grain yield in rainfed trials. Including S in the starter fertilizer did not result in increased yield. In‐furrow and over‐the‐row were as effective as 50 × 50 mm placement in increasing yield. Grain yield response to starter fertilizer was greatest and most profitable with irrigated corn produced under low soil test P (STP ≤ 15 mg kg−1) conditions. Conversion of early growth response into yield response to starter fertilizer appears to depend on soil water availability and on STP.