Does Strip Tillage or Fertilizer Placement Influence the Soybean Row Spacing Yield Response?.

Strip tillage adoption has increased as a means to alleviate cold, compacted soils in continuous and rotated corn production systems. Potential agronomic benefits include earlier planting dates, warmer soil temperatures, and greater fertilizer efficiencies, while less soil disturbance and fertilizer incorporation are environmentally appealing. Strip tillage can be loosely defined as any tillage that only loosens the soil and removes or incorporates residue in a narrow (10-20-cm) band and 5-20-cm deep ahead of planting.  Planting follows the strip tilling and the seed furrow is formed in the middle of these strips while the area between the crop rows remains undisturbed.  The most popular strip tillage implements incorporate four individual procedures into a single pass: 1) residue removal 2) residue sizing 3) narrow tillage with a knife or coulter, and 4) twin opposing coulters to form an elevated berm. This can be combined with dry or liquid fertilizer application and can be performed in the fall or spring or both. Soybean also has the ability to benefit from strip tillage; however, soybean yield response to strip till has tended to be less consistent. We plan to evaluate various soybean strip tillage treatments in small plot and large field scale trials to determine if this tillage approach can increase yields over conventional or no-tillage. Our specific objectives are: 1) evaluate the effect of strip tillage on soybean stand establishment, growth, and yield, 2) compare a 76-cm strip till system versus no-till for soybean growth and yield in 38-cm and 76-cm rowed soybean, 3) compare strip tillage with and without the use of in-furrow or banded fertilizers, and 4) develop Extension recommendations for the use of strip tillage for soybean production in WI. Data will be presented on two small plot trials and two on-farm large plot trials.