Monday, November 2, 2009
Convention Center, Exhibit Hall BC, Second Floor
Abstract:
Minnesota corn (Zea mays L.) farmers utilize starter fertilizers to increase early growth and nutrient uptake with the hope of ultimately increasing yield. Commercial blends of 10-15-0 (N-P-K) formulations have been used for many years because of widespread availability. Many other liquid fertilizer formulations with K are sold, but the benefits from K in starter are not clearly understood. This study assessed the impacts of N, P, K applied alone or in combination as a starter fertilizer on early corn growth, plant N, P, and K concentration, and nutrient uptake. Trials were arranged in a split plot design where main plots consisted of a control and five liquid starter treatments (N only, N+P, N+P+K, N+K, and K only) and two near isoline corn hybrids (DK 50-44 VT3 and DK 50-48 RR YGCB) comprised the sub plots. The same hybrids were used at four locations which tested medium or higher in soil P (>10 mg kg-1) and K (> 80 mg kg-1). Starter rates applied 10 kg N, 10 kg P, or 18 kg K ha-1. Starter P increased early plant growth and adding K increased growth more than P alone across locations. On average, hybrids did not differ in plant growth. Corn N, P, and K concentration was seldom influenced by starter treatments. Across locations, N+P+K starter treatments increased uptake more than other nutrient combinations. Starter N+P increased uptake of all nutrients greater than most other treatments (except N+P+K), even K uptake although none was applied. Increased K uptake was due to a significant relationship between growth and uptake. Data from the first year of this study confirms that P is important for early plant growth and nutrient uptake, but in certain circumstances the addition of K with P may be beneficial to further increase early plant growth.