Analysis of growth and yield of maize, sunflower and soybean grown at Balcarce, Argentina

Planting date and seeding rate are agronomic decisions that producers can use to maximize soybean [Glycine max (L) Merr.] seed yield and economic return. Current information on the response to planting date and seeding rate may underestimate the yield penalty for delayed planting in northern climates and overestimate the seeding rate required to optimize yield. The objective was to determine the effect of planting date and seeding rate on soybean seed yield at environments with different yield potentials in Iowa. Field experiments were conducted in six locations between 2003 and 2006 for a total of 13 environments. Four seeding rates were planted at four dates between late April and the middle of June. No yield difference existed between the late April and early May planting dates and the yield decline rate between each date was consistent among the six locations. Harvest plant populations were not influenced by planting date indicating that plant establishment does not pose a limitation to late April planting. Harvest plant populations required to reach 95% of the maximum yield were as great as 290,800 or as low as 194,000 plants ha -1 , for locations seeded in 38-cm row spacing and 157,300 to 211,800 plants ha -1 for locations seeded in 76-cm row spacing. Planting in late April or early May increased economic return ha -1 but there was no difference between seeding rates of 185,300 and 556,000 seeds ha -1 , accounting for additional seed costs. In the cool spring climate of the upper Midwest soybean producers can increase yield by planting soybean 1 to 2 wk earlier than current planting dates. These data also suggest that the optimal seeding rate for most locations is less than current seeding rates.

Soybean Seed Yield Response to Planting Date and Seeding Rate in the Upper Midwest

The sensitivity of soybean [Glycine max (L) Merr] main stem node accrual to ambient temperature has been documented in greenhousegrown plants but not with fi eld-grown plants in the north-central United States Biweekly V-node and R-stage, stem node number, internode length, and other traits were quantifi ed in an irrigated split-plot, four-replicate, randomized complete block experiment conducted in Lincoln, NE, in 2003–2004 Main plots were early-, mid-, late

/pdf/soybean-sowing-date-the-vegetative-reproductive-and-1ucd5c245e.pdf

Soybean Sowing Date: The Vegetative, Reproductive, and Agronomic Impacts

Soybean [Glycine max (L.) Merr.] area has increased tremendously in the upper Midwest over the last decade, but little information exists regarding the impact of management systems on soybean yield components. Our objective was to assess the effect of management system and planting date on soybean seed yield components and their development for environments typical of the upper Midwest. A field study was conducted from 1997 to 2000 using five management systems. Two newer released cultivars (CX232 and Spansoy 250) and one older cultivar (Hardin) were planted at two planting dates. Few interactions were observed in this study. Management system influenced development of the different yield components and produced seed mass ranging from 10.5 to 16.5 g 100 seed -1 , seed number from 2878 to 3824 seeds m -2 , pod number from 1182 to 1571 pods m -2 , and seeds per pod from 2.36 to 2.49 seeds pod -1 . Harvest index ranged from 56.2 to 58.0% across management systems. Hardin produced the highest harvest index (60.1%) and Spansoy 250 the lowest harvest index (54.5%). Tillage system affected yield components, with no-tillage systems having 15, 9, and 9% greater seed mass, seed number per square meter, and pod number per square meter than the conventional tillage system, respectively. Early planting date produced higher seed number, pod number, and harvest index but lower seed number per pod than the late planting date. In conclusion, differences in yield components and their development emphasize the complexity of plant compensation in response to management system and tillage system.

Response of Soybean Yield Components to Management System and Planting Date

planting date is a commonly manipulated man - agement practice in soybean ( Glycine max (L.) Merr.) production; however, the impacts of past and ongoing agronomic improvements, such as earlier planting, on genetic yield improvement and associated changes in seed protein and oil have not been evaluated. The objectives of this study were to determine if a 30-d difference in planting date affected measured rates of genetic improvement in (i) yield, (ii) seed mass, and (iii) seed protein and oil in the midwestern United States. research was conducted at Arlington, WI, Urbana, IL, and Lafayette, IN, during 2010 and 2011, using 59 Maturity Group (MG) II cul - tivars (released 1928-2008) at Wisconsin, and 57 MG III cultivars (released 1923-2007) at Illi - nois and Indiana, with targeted planting dates of 1 May and 1 June. Earlier planting provided higher yields (+3.1 kg ha −1 yr −1 ) than late planting in MG III soybean. Seed protein concentration decreased linearly over cultivar year of release at a rate of 0.191 (± 0.069) g kg −1 yr −1 for MG II, and 0.242 (± 0.063) g kg −1 yr −1 for MG III. Seed oil concentration increased over year of release at a rate of 0.142 (± 0.037) g kg −1 yr −1 for MG II, and 0.127 (± 0.039) g kg −1 yr −1 for MG III. The interaction between planting date and cultivar year of release for MG III yield suggested that the trend toward earlier planting is one agro - nomic improvement that, when coupled with genetic improvement, has provided a syner - gistic increase in on-farm soybean yields in the midwestern United States.

https://acsess.onlinelibrary.wiley.com/doi/pdf/10.2135/cropsci2012.03.0157

B. L. Vasilas

Papers

Effects of Planting Date on Two Soybean Cultivars: Seasonal Dry Matter Accumulation and Seed Yield1