‡2006 – 2017 quality estimates are weighted by yearly production estimates by state We Can Agronomic Management Simultaneously Increase Protein Concentration and Yield in Soybean? Vitor Rampazzo Favoretto and Frederick E. Below Crop Physiology Laboratory, Department of Crop Sciences, University of Illinois at Urbana-Champaign • Soybean [Glycine max (L.) Merr.] grain is important for the agricultural industry because of its sub-product meal, providing protein for animal production. • Soybean grain protein concentration (quality) has been decreasing, due to the modern crop management focus on yield (Figure 1). 1. Can individual agronomic management simultaneously increase seed protein concentration and yield in soybean? ☓ No, Soybean had greater yield, but similar or lower concentrations of grain protein when the management factors of narrow row spacing, full RM, foliar protection, P & K, or seed treatment were added individually. 2. Do multiple agronomic management inputs synergistically and simultaneously increase seed protein concentration and yield in soybean? ☓ No, The High Input approach, where management factor treatments are applied together was beneficial to yield, but seed protein concentration was usually lower. Identify independent and/or synergistic contributions of agronomic management factors to soybean seed protein level and yield. • Using Full-season RM varieties increased yield on average by 0.27 Mg ha -1 (Table 2). Because grain protein concentration was not consistently affected by maturity, the protein production increases by Full RM varieties were mainly driven by yield differences (Table 2). Sites Five trials were conducted in two years (2015, 2016) and at one of four locations (DeKalb (42 o N), Yorkville (41 o N) Champaign (40 o N), and Harrisburg (37 o N) in Illinois. Plots were 4-rows x 11m in length, in which the center 2 rows were harvested for yield with a plot combine. A grain sample was collected from each plot and grain protein concentration was determined by NIT. Protein production was estimated from yield and grain protein concentration, and all values are expressed at 13% moisture. An omission-addition plot design was used to evaluate the contribution of different management factors (Table 1), described below. All treatments were replicated 6 times. Fertilizer • No external addition to natural soil fertility, or • Addition of phosphorus (P) and potassium (K) using a MAP- based P fertilizer (MicroEssentials-SZ 12-40-0-10S-1Zn), banded 15 cm deep directly prior to planting at a rate of 84 kg P 2 O 5 ha -1 , and a MOP-based K fertilizer (Aspire, 0-0-58-0.5B), broadcast directly prior to planting at a rate of 84 kg K 2 O ha -1 . Foliar Protection • Fungicide and insecticide mixes, QuadrisTop + Endigo (Syngenta) or Priaxor + Fastac (BASF), were used and compared to no foliar applications. The treatment was applied at the R3 growth stage using a CO 2 -propelled backpack applicator. Seed Treatment • No seed treatment (naked seed) or fungicide-only seed treatment was compared to a full seed treatment (fungicide, insecticide and nematicide), with the specific seed-treatment products dependent upon the seed brand that was used. Row Spacing • Two row spacings of 51 or 76 cm, in both cases at a final stand of 395,000 plants ha -1 . Relative Maturity (RM) • A normal and a full-season variety (differing by 0.3 RM units) for the geographic region were included in each trial. MANAGEMENT FACTORS Treatment P & K Foliar Protection Seed treatment HIGH INPUT Yes Yes Full Omit Management -P and K None Yes Full -Foliar Protection Yes None Full -Seed Treatment Yes Yes Basic STANDARD None None Basic Add Management +P and K Yes None Basic +Foliar Protection None Yes Basic +Seed Treatment None None Full Table 1. The omission-addition design used to evaluate individual management factor treatments from Standard or High Input management systems. All treatments were evaluated using two relative maturity cultivars in 51 and 76 cm rows. Table 2. Soybean yield, grain protein concentration, and protein production as a function of variety maturity group (Normal or Full) for each site year. Values are averaged over two management input levels and two row spacing. Table 3. Soybean yield, grain protein concentration, and protein production as a function of different row spacing (51cm and 76 cm) for each site year. Values are averaged over two management input levels and two cultivars. 33 33.5 34 34.5 35 35.5 36 36.5 0 500 1000 1500 2000 2500 3000 3500 4000 Protein (%) Yield (kg.ha -1 ) Year YIELD (Kg\ha) PROTEIN (%) Source: USSEC ‡2006 – 2017 quality estimates are weighted by yearly production estimates by state Site-Year Yield Protein Protein production 51 cm 76 cm 51 cm 76 cm 51 cm 76 cm Mg ha -1 % Mg ha -1 DeKalb 2015 4.6† 3.9 34.5 34.7† 1.6† 1.4 Champaign 2015 6.3† 5.6 33.6 33.7 2.1† 1.9 Yorkville 2016 6.3† 5.3 35.6 35.6 2.2† 1.8 Champaign 2016 5.1† 4.6 34.7 34.9 1.8† 1.6 Harrisburg 2016 4.2† 3.8 35.1 35.4† 1.5† 1.3 † Significant difference between row spacing within a site-year at α = 0.1 Site-Year Yield Protein Protein production Normal Full Normal Full Normal Full Mg ha -1 % Mg ha -1 DeKalb 2015 4.2 4.4† 34.7 34.4 1.5 1.5† Champaign 2015 5.9 6.1† 33.6 33.7 2.0 2.1† Yorkville 2016 5.8 5.8 35.7 35.6 2.1 2.1 Champaign 2016 4.7 5.0† 34.5 35.2† 1.6 1.8† Harrisburg 2016 4.1 3.9† 35.7 34.8† 1.5 1.4† † Significant difference between maturity groups within a site-year at α = 0.1 Figure 3. Soybean yield (a), grain protein concentration (b), and protein production (a), as a function of different management factor additions or diminishments. Values are the average of all five site years, each with two RM varieties and two row spacings. • Foliar protection or P&K increased yield and protein production when added to the Standard system (Figure 3a), but decreased protein concentration (Figure 3b). Conversely, omitting P&K from the High Input system decreased yield and protein production, but increased protein concentration. Figure 2. Soybean yield (a), grain protein concentration (b), and protein production (a) as a function of Standard or High Input management. Values are the average of all five site years, each with two RM varieties and two row spacings. Figure 1. Average soybean yield (kg ha -1 ) and grain protein (%) for the United States over crop years from 1986 to 2016. D C C C A AB B AB d c c cd a ab b ab 1.5 1.6 1.7 1.8 1.9 2.0 2.1 4.5 5.0 5.5 6.0 Standard +Foliar +P & K +Seed treatment High Input -Foliar -P & K -Seed treatment Protein production ( Mg ha -1 ) Yield Mg ha -1 ) Yield Protein production (a) • Decreasing row spacing from 76 to 51 cm was beneficial for yield (with an average gain of 0.65 Mg ha -1 ), but decreased grain protein concentration by an average of 0.2 percentage points (Table 3). Thus, the increase in protein production (average gain of 0.22 Mg ha -1 ) from narrow rows was driven by the increase in grain yield (Table 3). • The addition of all management factor treatments (High Input) increased yield by an average of 0.4 Mg ha -1 (Figure 2a), but decreased grain protein concentration by 0.25 percentage points (Figure 2b). However, overall protein production was still higher with the High Input management (Figure 2a). B A b a 1.7 1.8 1.9 2 2.1 4.5 5 5.5 6 Standard High Input Protein Production ( Mg ha -1 ) Yield ( Mg ha -1 ) Yield Protein Production (a) Uppercase letter shows differences in Yield at α= 0.1 Lowercase letter shows differences in Protein production at α= 0.1 A B 33.5 33.8 34.1 34.4 Standard High Input Protein (%) (b) Uppercase letter shows differences in Protein at α= 0.1 33.5 33.8 34.1 34.4 Standard +Foliar Protection +P & K +Seed treatment High Input -Foliar Protection -P & K -Seed treatment Grain Protein (%) (b) A A A B BC BC C A Uppercase letter shows differences in Protein at α= 0.1 Lowercase letter shows differences in Protein production at α= 0.1 Uppercase letter shows differences in Yield at α= 0.1 Thanks to Mosaic, Syngenta, BASF, Bayer CropScience, Winfield United, The Illinois Soybean Association, and The United Soybean Board for supporting this research.