Updated December 21, 2023:
RESEARCH APPROACH:
Understanding soybean yield responses to foliar protection and increased fertility may help producers better position soybean varieties. The objective of this study is to identify ‘offensive’ soybean varieties, or varieties with adaptability to high yield environments (i.e., responsive to crop management), and ‘defensive’ soybean varieties, or varieties with acceptable yields in low yield environments (i.e., resilience to pests and diseases, and tolerance to nutrient deficiency).
In our approach, ‘Offensive’ varieties are the genotypes that combine above-average yield increases from: (i) foliar protection [PROT, foliar protection (insecticide and fungicide) versus no-foliar protection], (ii) fertility [FERT, yield change between 0 and 187 lbs/acre of MicroEssentials S10 (N, P, & S)], and (iii) yield performance under the combination of both treatments (BOTH, yield with additional fertility and foliar protection).
Conversely, varieties with high yield performance under no additional fertilizer or foliar protection (Control) and low yield response to foliar protection (low PROT) were considered ‘Defensive’ varieties. The 2018 trial evaluated 61 soybean varieties from six different brands, and maturity groups ranging from 2.1 to 4.. Thirty-six varieties were evaluated at Yorkville, Champaign, and Harrisburg. The trial was planted using a precision plot planter (SeedPro 360, ALMACO, Nevada, IA) at Harrisburg, IL (2 May 2018), Champaign, IL (16 May 2018), and Yorkville, IL (19 May 2018). Plots were 16 feet in length with 30-inch row spacing and two rows in width to achieve a final population of approximately 160,000 plants acre-1. The foliar protection treatment was applied using a tractor mounted sprayer and consisted of an insecticide (Endigo® ZC; Lambda-cyhalothrin + Thiamethoxam) and fungicide (Trivapro™; Benzovindiflupyr + Azoxystrobin + Propiconazole) application at the R3 stage at a rate of 3.8 and 13.7 oz per acre, respectively. Application dates for foliar protection were 2 July 2018 (Harrisburg), 17 July 2018 (Champaign), and 25 July 2018 (Yorkville). The fertility treatment consisted of a premium MAP-based phosphorus fertilizer that also contained S, MicroEssentials S10 (MES10, 12-40-0-10S; The Mosaic Company, Plymouth, MN), applied at 187 lbs acre-1 in a subsurface band 4 to 6 inches deep immediately prior to planting using a research-scale fertilizer toolbar to provide 22 lbs N, 75 lbs P2O5, and 18 lbs S per acre. Plots were arranged in a split-plot RCB design with four replications. The main plot was fertility (n=2) and the split-plot was foliar protection (n= 2) and variety (n=36) randomly assigned within each treatment block. Data were analyzed using analysis of variance with the PROC MIXED procedure of SAS (Version 8, SAS Institute, Cary, NC) and means were separated using Fisher’s protected LSD test at the 0.10 level of significance. Variety, fertility, and foliar protection were considered fixed effects, while block and interactions with blocks were considered random effects. At maturity, yield (bu acre-1) was measured with a plot combine and adjusted to constant moisture (i.e., 13% grain moisture concentration).
YIELD RESULTS:
Soil pH, organic matter, and fertility levels were relatively adequate, allowing for growing conditions generally conducive to favorable grain yields (Table 2). The 2018 crop growing season experienced excessive rainfall in June across the state (Table 3). During the remainder of the growing season rainfall was similar to the 30-year average. Throughout the growing season temperatures were fairly consistent with the 30-year average, with the exception of May being relatively hot across locations and September in Champaign.
Location significantly affected grain yields, with average yields of 90.6, 86.8, and 79.0 bu acre-1 for Yorkville, Champaign, and Harrisburg, respectively (Tables 5 to 19). Foliar protection increased soybean yield at Champaign and Harrisburg, but did not increase yield at Yorkville due to dry conditions during July and August, and low disease and insect pressure. Unlike foliar protection, additional fertility increased grain yield in Yorkville. On average, foliar protection increased yield by +0.7, +6.9 and +3.5 bu acre-1 at Yorkville, Champaign, and Harrisburg, respectively, while fertility additions altered yield by +1.6, -0.8, and +0.2 bu acre-1 at these same sites (Figures 1 to 3). Additional fertility in combination with foliar protection generated the largest yield responses at Yorkville (+2.3 bu acre-1) and Harrisburg (+3.7 bu acre-1) compared to fertility or foliar protection alone. At Champaign, foliar protection alone resulted in the largest response at +6.9 bu acre-1.
Across all three locations, varieties had significantly different grain yields. With standard management (no fertility additions or foliar protection) there was a yield range of 25, 28, and 20 bu acre-1 from highest to lowest yielding varieties at Yorkville, Champaign, and Harrisburg, respectively. The greatest range in yield response among from varieties was from foliar protection at Harrisburg (36 bu acre-1).
The highest yields recorded were 107.8, 103.4, and 91.7 bu acre-1 at Yorkville, Champaign, and Harrisburg, respectively (varieties AG36X6, S41XS98, and AG42X6 and P46A93X, respectively). In Yorkville, the top five yields were from the following varieties (without repeating a variety): AG36X6 (107.8 bu acre-1), RX3896 (104.9 bu acre-1), AG32X8 (101.9 bu acre-1), S34XT69 (101.9 bu acre-1), AG37X9 (101.3 bu acre-1), RX3337 (101.3 bu acre-1), and S37XT28 (100.2 bu acre-1). Moving down the state of Illinois, the top five yields at Champaign were achieved by the following varieties: S41XS98 (103.4 bu acre-1), S39XT68 (100.5 bu acre-1), AG37X9 (100.4 bu acre-1), AG36X6 (100.4 bu acre-1), GH3546X (99.7 bu acre-1), AG32X8 (98.6 bu acre-1), AG36X6 (98.6 bu acre-1), and S36XT09 (97.7 bu acre-1). Harrisburg had the highest overall yields achieved by: AG42X6 (91.7 bu acre-1), P46A93X (91.7 bu acre-1), AG42X6 (91.4 bu acre-1), AG41X8 (90.7 bu acre-1), S39XT68 (88.4 bu acre-1), S44XS68 (88.4 bu acre-1), and S37XS89 (88.0 bu acre-1).
Yield responses to additional fertility among individual varieties compared to the untreated control at all locations ranged from -11.8 to +11.7 bu acre-1 indicating different genetic sensitivity to soil nutrient availability. Foliar protection application yield-responses ranged from -12.5 to +19.7 bu acre-1 and when applied in combination with additional fertility the yield changes ranged from -13.9 to +14.3 bu acre-1. The differences observed in yield performance among varieties and their interaction with agronomic management across environments highlights the importance of soybean genetic characterization in response to different agronomic management factors. These characterizations are summarized in the second half of this report.
CHARACTERIZATION OF VARIETIES IN RESPONSE TO MANAGEMENT:
The differences observed in yield performance among varieties and their interaction with agronomic management across environments highlights the opportunity of soybean genetic characterization in response to different agronomic management factors.
The objective of the Soybean MYP trial is to characterize elite soybean cultivars for their yield response to different agronomic management conditions. Variety decile ranks for yield performance under low agronomic management input (Yield Control), yield response to increased fertility (FERT), yield response to foliar protection (PROT), yield response to foliar protection combined with increased fertility compared to the control (PROT + FERT), and yield performance ranking compared to other varieties resulting from the combination of both treatments (Yield BOTH) across locations are presented in Table 20. Agronomists and farmers may use the score from each parameter to better position their soybean variety based on the agronomic performance and response to agronomic management at different locations. ‘Defensive’ varieties can be considered as ones having a high ranking for Yield Control and a low ranking for yield response to foliar protection (low PROT), while ‘Offensive’ varieties can be considered ones having a high ranking for Yield Both and high rankings for yield response to foliar protection (high PROT) and increased fertility (high FERT).
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RESEARCH APPROACH:
Understanding soybean yield responses to foliar protection and increased fertility may help producers better position soybean varieties. The objective of this study is to identify ‘Offensive’ soybean varieties, or varieties with adaptability to high yield environments (i.e., responsive to crop management), and ‘Defensive’ soybean varieties, or varieties with acceptable yields in low yield environments (i.e., resilience to pests and diseases, and tolerance to nutrient deficiency). In our approach, ‘Offensive’ varieties are the genotypes that combine above-average yield increases from: (i) foliar protection [PROT, foliar protection (insecticide and fungicide) versus no-foliar protection], (ii) fertility [FERT, yield change
between 0 and 187 lbs/acre of MicroEssentials S10 (N, P, & S)], and (iii) yield performance under the combination of both treatments (BOTH, yield with additional fertility and foliar protection). Conversely, varieties with high yield performance under no additional fertilizer or foliar protection (Control) and low yield response to foliar protection (low PROT) were considered ‘Defensive’ varieties.
The 2018 trial evaluated 61 soybean varieties from six different brands, and maturity groups ranging from 2.1 to 4.8. Thirty-six varieties were evaluated at Yorkville, Champaign, and Harrisburg.
The trial was planted using a precision plot planter (SeedPro 360, ALMACO, Nevada, IA) at Harrisburg, IL (2 May 2018), Champaign, IL (16 May 2018), and Yorkville, IL (19 May 2018). Plots were 16 feet in length with 30-inch row spacing and two rows in width to achieve a final population of approximately 160,000 plants acre-1. The foliar protection treatment was applied using a tractor mounted sprayer and consisted of an insecticide (Endigo® ZC; Lambda-cyhalothrin + Thiamethoxam) and fungicide (Trivapro™; Benzovindiflupyr + Azoxystrobin + Propiconazole) application at the R3 stage at a rate of 3.8 and 13.7 oz per acre, respectively. Application dates for foliar protection were 2 July 2018 (Harrisburg), 17 July 2018 (Champaign), and 25 July 2018 (Yorkville). The fertility treatment consisted of a premium MAP-based phosphorus fertilizer that also contained S, MicroEssentials S10 (MES10, 12-40-0-10S; The Mosaic Company, Plymouth, MN), applied at 187 lbs acre-1 in a subsurface band 4 to 6 inches deep immediately prior to planting using a research-scale fertilizer toolbar to provide 22 lbs N, 75 lbs P2O5, and 18 lbs S per acre.
Plots were arranged in a split-plot RCB design with four replications. The main plot was fertility (n=2) and the split-plot was foliar protection (n= 2) and variety (n=36) randomly assigned within each treatment block. Data were analyzed using analysis of variance with the PROC MIXED procedure of SAS (Version 8, SAS Institute, Cary, NC) and means were separated using Fisher’s protected LSD test at the 0.10 level of significance. Variety, fertility, and foliar protection were considered fixed effects, while block and interactions with blocks were considered random effects. At maturity, yield (bu acre-1) was measured with a plot combine and adjusted to constant moisture (i.e., 13% grain moisture concentration).
YIELD RESULTS:
Soil pH, organic matter, and fertility levels were relatively adequate, allowing for growing conditions generally conducive to favorable grain yields (Table 2). The 2018 crop growing season experienced excessive rainfall in June across the state.
During the remainder of the growing season rainfall was similar to the 30-year average. Throughout the growing season temperatures were fairly consistent with the 30-year average, with the exception of May being relatively hot across locations and September in Champaign.
Location significantly affected grain yields, with average yields of 90.6, 86.8, and 79.0 bu acre-1 for Yorkville, Champaign, and Harrisburg, respectively (Tables 5 to 19). Foliar protection increased soybean yield at Champaign and Harrisburg, but did not increase yield at Yorkville due to dry conditions during July and August, and low disease and insect pressure. Unlike foliar protection, additional fertility increased grain yield in Yorkville. On average, foliar protection increased yield by +0.7, +6.9 and +3.5 bu acre-1 at Yorkville, Champaign, and Harrisburg, respectively, while fertility additions altered yield by +1.6, -0.8, and +0.2 bu acre-1 at these same sites (Figures 1 to 3). Additional fertility in combination with foliar protection generated the largest yield responses at Yorkville (+2.3 bu acre-1) and Harrisburg (+3.7 bu acre-1) compared to fertility or foliar protection alone. At Champaign, foliar protection alone resulted in the largest response at +6.9 bu acre-1.
Across all three locations, varieties had significantly different grain yields. With standard management (no fertility additions or foliar protection) there was a yield range of 25, 28, and 20 bu acre-1 from highest to lowest yielding varieties at Yorkville, Champaign, and Harrisburg, respectively. The greatest range in yield response among from varieties was from foliar protection at Harrisburg (36 bu acre-1).
The highest yields recorded were 107.8, 103.4, and 91.7 bu acre-1 at Yorkville, Champaign, and Harrisburg, respectively (varieties AG36X6, S41XS98, and AG42X6 and P46A93X, respectively). In Yorkville, the top five yields were from the following varieties (without repeating a variety): AG36X6 (107.8 bu acre-1), RX3896 (104.9 bu acre-1), AG32X8 (101.9 bu acre-1), S34XT69 (101.9 bu acre-1), AG37X9 (101.3 bu acre-1), RX3337 (101.3 bu acre-1), and S37XT28 (100.2 bu acre-1). Moving down the state of Illinois, the top five yields at Champaign were achieved by the following varieties: S41XS98
(103.4 bu acre-1), S39XT68 (100.5 bu acre-1), AG37X9 (100.4 bu acre-1), AG36X6 (100.4 bu acre-1), GH3546X (99.7 bu acre-1), AG32X8 (98.6 bu acre-1), AG36X6 (98.6 bu acre-1), and S36XT09 (97.7 bu acre-1). Harrisburg had the highest overall yields achieved by: AG42X6 (91.7 bu acre-1), P46A93X (91.7 bu acre-1), AG42X6 (91.4 bu acre-1), AG41X8 (90.7 bu acre-1), S39XT68 (88.4 bu acre-1), S44XS68 (88.4 bu acre-1), and S37XS89 (88.0 bu acre-1).
Yield responses to additional fertility among individual varieties compared to the untreated control at all locations ranged from -11.8 to +11.7 bu acre-1 indicating different genetic sensitivity to soil nutrient availability. Foliar protection application yield-responses ranged from -12.5 to +19.7 bu acre-1 and when applied in combination with additional fertility the yield changes ranged from -13.9 to +14.3 bu acre-1. The differences observed in yield performance among varieties and their interaction with agronomic management across environments highlights the importance of soybean genetic characterization in response to different agronomic management factors. These characterizations are
summarized in the second half of this report.
CHARACTERIZATION OF VARIETIES IN RESPONSE TO MANAGEMENT:
The differences observed in yield performance among varieties and their interaction with agronomic management across environments highlights the opportunity of soybean genetic characterization in response to different agronomic management factors.
The objective of the Soybean MYP trial is to characterize elite soybean cultivars for their yield response to different agronomic management conditions. Variety decile ranks for yield performance under low agronomic management input (Yield Control), yield response to increased fertility (FERT), yield response to foliar protection (PROT), yield response to foliar protection combined with increased fertility compared to the control (PROT + FERT), and yield performance ranking compared to other varieties resulting from the combination of both treatments (Yield BOTH) across locations are presented in Table 20. Agronomists and farmers may use the score from each parameter to better position their soybean variety based on the agronomic performance and response to agronomic management at different locations. ‘Defensive’ varieties can be considered as ones having a high ranking for Yield Control and a low ranking for yield response to foliar protection (low PROT), while ‘Offensive’ varieties can be considered ones having a high ranking for Yield Both and high rankings for yield response to foliar protection (high PROT) and increased fertility (high FERT).