Breaking Soybean Yield Barriers: Integrating Crop Production Practices & Comprehensive Fertilization Strategies – a Cropping System Approach

This project is studying the effects of different farming systems on soybean yield in major production regions of the Americas. The specific research objectives are to: 1) quantify soybean yields across various production and fertilization practices, and evaluate the interaction among these practices, 2) quantify the yield gap between common farmer practice and more intensive management systems, 3) measure nutrient uptake and removal across regions and cropping strategies, and 4) examine nutrient partitioning and movement between soybean plant organs.

Field experiments were established in 2014 near Scandia (Kansas, USA), Ponta Grossa (Parana, Brazil), and Oliveros (Santa Fe, Argentina). The Scandia experiments were established under both dryland and irrigated conditions. At this time only the Scandia site has yield data to report. Sites in Brazil and Argentina have been planted and are under development.

Treatments at Scandia included common farmer practice (FP); comprehensive fertilization (CF) which was essentially FP plus fertilizer input (N, P, K, S, and micronutrients) according to university recommendations; production intensity (PI) which included narrower rows, higher population, but no fertilizer; ecological intensification (EI) which was essentially PI plus fertilizer input; and an advanced (AD) treatment which was EI plus further enhanced fertilization.

The Scandia dryland FP and CF treatments each yielded 34 bu/A (2,280 kg/ha). The PI, EI and AD treatments yielded 61 bu/A (4,090 kg/ha) on average. Fertilization increased yield in the EI and AD treatments by an average of 7 bu/A (470 kg/ha) over PI, but this increase was not statistically significant. The Scandia irrigated FP and CF yields averaged 48 bu/A (3,220 kg/ha) and were not statistically different, but it should nevertheless be noted that the CF treatment yielded 6 bu/A (400 kg/ha) more than FP. The more intensive treatments (PI, EI and AD) produced an average yield of 83 bu/A (5,560 kg/ha), significantly more than FP and CF. There was no statistically significant difference in yield among these three treatments, but the EI treatment (with fertilizer) yielded 8 bu/A (540 kg/ha) more than PI (no fertilizer).

There were yield gaps documented between the FP and intensified treatments. For dryland production, the difference between FP and intensification (average PI, EI, AD) was 27 bu/A (1,810 kg/ha) or 44%, while under irrigated conditions it was 38 bu/A (2,550 kg/ha) or 46%. This study is planned to continue for a total of 3 years across locations in Argentina, Brazil and the USA.