Agronomic Evaluation of Fertilizer Placement Methods for No‐Tillage Sorghum in Vertisol Clays

One goal in conservation farming systems is to optimize fertilizer use while reducing the loss of soil by water erosion. This requires evaluation of fertilizer application methods that minimize physical disturbance of protective crop residues and the soil surface and allow efficient uptake of added nutrients by the crop. We conducted this study to determine which of several surface and subsurface fertilizer application techniques would be the most beneficial to plant responses. A 3‐yr randomized block study was conducted on a Houston Black clay (fine, montmorillonitic, thermic Udic Pellusterts) at Temple, TX. Nitrogen (N) and phosphorus (P) uptake and grain yield were measured for the sorghum [ Sorghum bicolor (L.) Moench] test crop. All methods performed equally as indicated by crop yield responses and plant N and P contents. Based on these results and in conjunction with prior machine field performance testing, we have selected the coulter‐nozzle applicator for fertilizer application in our conservation tillage research program.