Optimizing Soybean Nutrition in the Mid South
Crop Genetics Research Unit
2012 Annual Report
1a.Objectives (from AD-416):
Identify optimal potash and phosphate requirements for soybean grown in rotation with corn. Determine the influence of Bradyrhizobia inoculation on soybean yield and nutritional status in multiple production systems. Define best fertilizer management strategies for wheat/soybean double crop systems.
1b.Approach (from AD-416):
Plant soybean corn on lighter textured soils commonly used for corn or cotton production. Apply multiple rates of potash or phosphate to both corn and soybean with other essential nutrients applied according to soil test results. Maintain plot integrity throughout study. Conduct tests at multiple locations when possible. Inoculate soybean with multiple available inoculants and plant soybean in rotation with cotton, corn and soybean to determine when seed inoculants are needed to optimize yield. Grow Maturity Group IV and V soybean following wheat. Investigate multiple fertilization strategies and timing for optimal input.
Trials to determine the influence of soybean inoculation on soybean yield and nutritional status in multiple production systems for 2011 were conducted in multiple locations with soybean following multiple crops in rotation. Approximately 7 unique soybean inoculants were tested in multiple crop rotations, and 12 fungicide x inoculant combinations were evaluated. Data obtained in 2011 has been summarized and submitted to stakeholders in both written and oral format on the state level. One key result is that at a location following the flood near Redwood, MS, soybean inoculation or seed treatment fungicide did not influence yield as compared to yield from untreated seed lots. Trials for 2012 have been planted and preliminary stand counts have been taken.
Trials to define best fertilizer management strategies for wheat/soybean double crop systems were attempted in 2011, but non-uniform soybean stand after burning of wheat stubble and watering for emergence resulted in erratic data. For 2012, wheat has been harvested as of 5-25-2012, and soybean will be planted when adequate soil moisture is achieved for planting. For 2012, trial locations were moved to a field with a lateral overhead irrigation system as a contingency to hedge against non-uniform stands due to poor soil moisture. In general trials will investigate the utility of starter fertilizers in a double crop system, and attempt to determine optimal input timing for soybean double cropped with wheat.