Deep Banding Phosphorus and Potassium Fertilizers for Corn Managed with Ridge Tillage
Broadcast fertilization leads to stratification of soil P and K in the ridge-till system, which may reduce fertilizer use efficiency. This study evaluated the response of corn (Zea mays L.) to broadcast or deep-band (15- to 20-cm depth) placements in 15 site–years. Fertilization rates were 0 to 56 kg P ha−1 and 0 to 132 kg K ha−1 Soil-test P (STP) and K (STK) were higher in the top 15-cm layer of the ridges. Phosphorus increased early plant growth (V5 stage) in five sites, early P uptake in nine sites, and grain yield in seven sites. Yield was increased by P when STP was <22 mg P kg−1 (Bray-1) in the top 15-cm layer of ridges or <18 mg P kg−1 in the top 15 cm of ridges and valleys. The P placements seldom differed (the deep-band P was better in one site). Potassium increased growth in 6 sites, K uptake in 14 sites, and grain yield in nine sites. The deep-band K increased yield over the broadcast K in four sites. The yield response to broadcast K across sites was not correlated with STK, but the response to deep-band K was negatively and linearly correlated with STK from various sampling positions. Corn responded to deep-band K in soils with above-optimum STK according to current soil-test interpretations. The results showed that both placements usually were similarly effective for P, and that deep banding often was superior for K.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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