Research Conducted
Soybean variety ND 17009GT was seeded on May 27, 2022. The seeding rate was 195,000 PLS/ac with Row to Row distance of 30”. There were 12 irrigation treatments: I = Full irrigation; Wv = Deficit irrigation during vegetative [(VE – V(n)] stage; Wf = Deficit irrigation during flowering [R1-R2] stage; Wp= Deficit irrigation during pod development [R3-R4] stage; Ws = Deficit irrigation during seed filling [R5-R6] stage; Wm = Deficit irrigation during maturity [R7-R8] stage; Wvf = Deficit Irrigation during vegetative + flowering stages; Wvp = Deficit irrigation during vegetative + pod development stages; Wvs = Deficit irrigation during vegetative + seed filling stages; Wvm = Deficit irrigation during vegetative + maturity stages; Wsm = Deficit irrigation during seed filling + maturity stages; and R = rainfed.
Why the research is important to ND soybean farmers
The insights obtained from this research regarding appropriate irrigation amounts and timing will assist soybean producers in western North Dakota in applying the precise amount of water at the right moment. The ultimate advantages will include improved yield, quality, water productivity, and soil health, as well as reduced leaching, environmental pollution, and disease occurrence, leading to increased profitability for farms.
Final findings of the research
The NDVI and NDRE data from the aerial images showed that the senescence occurred at a higher pace in plots with treatment R, WP, and Wvp compared to others. The grain number per plant was lower for R (45) Wvf (48) compared to others that had 63 to 77 grains per plant. The soybean grains under treatments Wp and Wvp had the highest amount of protein (42.2%) followed by treatment R (40.3%). Other treatments had 37.9-39.8% of grain protein. The treatment Wsm produced the highest grain yield, which was statistically on par with treatments Wm, Wvm, Ws, Wvs, I, and Wv. A marked decline in soybean yield occurred under treatments wf, Wvf, Wp, Wvp, and R (Figure 1).
Benefits/Recommendations to North Dakota soybean farmers and industry
The findings of this study indicate a potential for conserving irrigation water while maintaining soybean grain yield, provided that the escaping of irrigation does not occur at the flowering and pod development stages. The North Dakota soybean farmers and industry can benefit from these findings by reducing irrigation management costs and mitigating environmental pollution, all while sustaining soybean yield and ensuring a prosperous future. To confirm and validate these results, we plan to replicate this study in FY 2023-24.