Individual and Combined Effects of Planting Date, Seeding Rate, Relative Maturity, and Row Spacing on Soybean Yield

Abstract

Planting date (PD), seeding rate (SR), relative maturity (RM) of cultivars, and row spacing (RS) are primary management factors affecting soybean (Glycine max (L.) Merr.) yield. The individual and synergistic effects of PD, SR, RM, and RS on seed yield and agronomic characteristics in North Dakota were herein investigated. Early and late PD, early and late RM cultivars, two SR (408,000 and 457,000 seed ha−1), and two RS (30.5 and 61 cm) were evaluated in four total environments in 2019 and 2020. Maximizing green canopy cover prior to the beginning of flowering improved seed yield. Individual factors of early PD and narrow RS resulted in yield increase of 311 and 266 kg ha−1, respectively. The combined factors of early PD, late RM, high SR, and narrow RS improved yield by 26% and provided a $350 ha−1 partial profit over conventional practices. Canopy cover and yield had relatively weak relationships with r2 of 0.36, 0.23, 0.14, and 0.21 at the two trifoliolate, four trifoliolate, beginning of flowering, and beginning of pod formation soybean growth stages, respectively. Producers in the most northern soybean region of the USA should combine early planting, optimum RM cultivars, 457,000 seed ha−1 SR, and 31 cm RS to improve yield and profit compared to current management practices.

Using Canopy Measurements to Predict Soybean Seed Yield

“…For Example, Ma et al [8] suggest measuring NDVI between R4 and R5 stages to screen and rank soybean genotypes. Although the models were validated, we demonstrate the applied usage of the models from Table 5 using sensor data from an experimental unit using the recommended farming practices from the north-central USA region [44]. Using the stepwise model in Table 5 with the same measurement data from the same experimental unit with an actual yield of 3723 kg ha −1 and measurements of 0.72, 57.8, 0.82, 92.8, 0.84, and 85.7 for NDVI at R1, PAR at R1, NDVI at R3, FGCC at R3, NDVI at R5, and PAR at R5, respectively, the estimated yield is 3711 kg ha −1 .…”