Nitrous oxide emission during a soybean [Glycine max (l.) Merrill] culture: inoculation and nitrogen fertilization effects

El óxido nitroso absorbe radiación infrarroja contribuyendo al efecto invernadero; este gas es producido principalmente en el suelo, mediante los procesos de nitrificación y denitrificación. En un estudio a campo, sobre un suelo Argiudol típico, se evaluó el efecto de la fertilización y la inoculación con Bradyrhizobium japonicum en un cultivo de soja [Glycine max (L.) Merrill], sobre las emisiones de óxido nitroso. Los gases se extrajeron de cilindros de PVC y la lectura se realizó con cromatografía gaseosa. Las emisiones presentaron valores crecientes desde la siembra hacia madurez fisiológica del cultivo, para todos los tratamientos; este comportamiento fue concomitante con la evolución presentada por la humedad edáfica. La fertilización nitrogenada aumentó significativamente (P<0,05) las emisiones y la variable inoculación solo presentó efectos con el mayor nivel de fertilización (P=0,09). Los valores más elevados se observaron en los tratamientos fertilizados con mayor dosis e inoculados. La variable que mejor explica las emisiones es el nivel de nitratos del suelo (r2 = 0,1899; P=0,0231).Nitrous oxide gas absorbs infrared radiation contributing to the greenhouse effect. This gas is produced mainly in soil, by means of the processes of nitrification and denitrification. In a field study in Buenos Aires, on a Typic Argiudol, we evaluated the effect of fertilization and inoculation with Bradyrhizobium japonicum during a soybean culture [Glycine max (L.) Merrill], on nitrous oxide emisions. Gases were sampled with PVC cylinders and measured by gaseous chromatography. Emissions presented increasing values from seeding towards physiological maturity for all treatments. This evolution correlated well with soil nitrates and moisture. Nitrogen fertilization significantly increased (P<0.05) nitrous oxide emissions and inoculation only had a significant effect with the highest level of fertilization (P=0.09). Plots fertilized at the highest dose and inoculated gave the greatest nitrous oxide emissions. The variable that better explains the emissions was the nitrate level (r2 = 0.1899; P=0.0231).Fil: Ciampitti, Ignacio Antonio. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Edafología; ArgentinaFil: Ciarlo, Esteban Ariel. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Edafología; ArgentinaFil: Conti, Marta Elvira. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Edafología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Sulfur fertilization technology in the Argentine Pampas region : a review

Sulfur (S) deficiencies in grain crops have become increasingly frequent worldwide, including the Argentine Pampas region, located in South America. The objective of this work is to review recent research literature regarding S fertilization in the Argentine Pampas region, with emphasis on technological issues. The S fertilization in this region has grown sharply over recent years and, simultaneously, more scientific literature has been generated. A knowledge gap is recognized on field research studies related to elemental sulfur (ES) fertilization and its relative agronomic effectiveness in comparison to soluble S sources. By far, solid sulfate fertilizers are the most widespread S sources applied by farmers in the Pampas region. Nonetheless, application of liquid sources has increased over recent times. Overall, similar agronomic performance among sulfate sources has been reported. Additionally, similar effectiveness was documented between micronized ES and sulfate sources for different crops, with the exception of some site-specific conditions where effectiveness of sulfate sources may outperform ES. This review manuscript contributes to synthesize current knowledge regarding S fertilization technology and identify research needs in this matter.La frecuencia de ocurrencia de deficiencias de azufre (S) en cultivos de grano se incrementó a nivel mundial, incluyendo la Región Pampeana argentina, localizada en Sudamérica. El objetivo del trabajo es realizar una revisión de la literatura científica sobre fertilización azufrada en la Región Pampeana, con énfasis en aspectos tecnológicos. La adopción de la fertilización azufrada creció marcadamente en ésta región y simultáneamente aumentó la cantidad de publicaciones científicas en el tema. Sin embargo, existe una brecha de conocimiento sobre la fertilización con azufre elemental (AE) y su efectividad agronómica relativa a fuentes azufradas solubles. Los fertilizantes sulfatados sólidos son, con creces, las fuentes de S más utilizadas en la Región Pampeana aunque la aplicación de fuentes líquidas se incrementó en los últimos tiempos. En términos generales, se ha reportado similar efectividad agronómica entre fuentes sulfatadas. Asimismo, se ha observado similar efectividad agronómica entre el AE micronizado y fuentes sulfatadas en diferentes cultivos, con la excepción de condiciones sitio-específicas donde las fuentes sulfatadas pueden presentar una mejor performance. Esta revisión contribuye a sintetizar el conocimiento vigente sobre tecnología de fertilización azufrada y puede resultar de interés para establecer necesidades de investigación en este tema.EEA PergaminoFil: Torres Duggan, Martín. Tecnoagro; ArgentinaFil: Melgar, Ricardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino. Departamento Suelo y Fertilidad; ArgentinaFil: Rodríguez, Monica Beatriz. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Fertilidad y Fertilizantes; ArgentinaFil: Lavado, Raúl Silvio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; ArgentinaFil: Ciampitti, Ignacio Antonio. Purdue University. Agronomy Department; Estados Unido

Assessing Nitrogen Limitation in Inoculated Soybean in Southern Brazil

Core Ideas Soybean yield did not respond to low starter fertilizer N rates in soils with high organic matter content. Nitrogen limitation tended to be greater in low compared with medium-high yield levels. Nitrogen limitation is potentially related to lower contribution of N coming from biological nitrogen fixation (BNF) and mineralization. Overcoming potential N limitation in soybean [Glycine max (L.) Merr.] is a critical factor for sustaining plant nutrient demand and improving productivity. Following this rationale, a set of studies were executed in southern Brazil with the goals of quantifying yield response to early season fertilizer N rates (up to 40 kg ha−1), “starter N fertilization,” and to understand if soybean seed yields are limited by N (testing a non-limiting N scenario) when grown in soils with medium to high organic matter content. The main key outcomes of this research were: (i) starter N fertilization did not increase yields compared with non-fertilized soybean, potentially highlighting the absence of an early season N limitation; and (ii) N limitation was observed when soybean yields were compared with non-limiting N scenario and it tended to be greater in low compared with medium-high yield levels, potentially connected with co-limitations on both N sources (N2 fixation and mineralization) to satisfy soybean N demand. Producing soybean in a sustainable manner implies focus on production practices to conserve and, potentially, to increase soil organic matter on a long-term basis. Furthermore, it requires enhancing the biological N2 fixation process for satisfying the large plant N demand for achieving high soybean yields. Future research should be focused on understanding factors governing biological N2 fixation and N mineralization processes in soybean grown in soils with medium-high organic matter content.Fil: Ambrosini, Vítor Gabriel. Universidade Federal do Rio Grande do Sul; BrasilFil: Vieira Fontoura, Sandra Mara. Fundação Agrária de Pesquisa Agropecuária; BrasilFil: Paulo de Moraes, Renato. Fundação Agrária de Pesquisa Agropecuária; BrasilFil: Carciochi, Walter Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Ciampitti, Ignacio Antonio. Kansas State University; Estados UnidosFil: Bayer, Cimélio. Universidade Federal do Rio Grande do Sul; Brasi

Soybean seed yield response to plant density by yield environment in north america

Inconsistent soybean [Glycine max (L.) Merr.] seed yield response to plant density has been previously reported. Moreover, recent economic and productive circumstances have caused interest in within-field variation of the agronomic optimal plant density (AOPD) for soybean. Thus, the objectives of this study were to: (i) determine the AOPD by yield environments (YE) and (ii) study variations in yield components (seed number and weight) related to the changes in seed yield response to plant density for soybean in North America. During 2013 and 2014, a total of 78 yield-to-plant density responses were evaluated in different regions of the United States and Canada. A soybean database evaluating multiple seeding rates ranging from 170,000 to 670,000 seeds ha–1 was collected, including final number of plants, seed yield, and its components (seed number and weight). The data was classified in YEs: Low (LYE, 4.3 Mg ha–1). The main outcomes were: (i) AOPD increased by 24% from HYE to LYE, (ii) per-plant yield increased due to a decrease in plant density: HYE > MYE > LYE, and (iii) per-plant yield was mainly driven by seed number across plant densities within a YE, but both yield components influenced per-plant yield across YEs. This study presents the first attempt to investigate the seed yieldto- plant density relationship via the understanding of plant establishment and yield components and by exploring the influence of weather variables defining soybean YEs.Fil: Carciochi, Walter Daniel. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Agencia de Extensión Rural Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Schwalbert, Rai. Kansas State University; Estados UnidosFil: Andrade, Fernando Héctor. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Agencia de Extensión Rural Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Corassa, Geomar M.. Kansas State University; Estados UnidosFil: Carter, Paul. Kansas State University; Estados UnidosFil: Gaspar, Adam P.. Kansas State University; Estados UnidosFil: Schmidt, John. Kansas State University; Estados UnidosFil: Ciampitti, Ignacio Antonio. Kansas State University; Estados Unido

Tecnología de fertilización azufrada en la Región Pampeana Argentina : una revisión

61-73La frecuencia de ocurrencia de deficiencias de azufre (S) en cultivos de grano se incrementó a nivel mundial, incluyendo la Región Pampeana argentina, localizada en Sudamérica. El objetivo del trabajo es realizar una revisión de la literatura científica sobre fertilización azufrada en la Región Pampeana, con énfasis en aspectos tecnológicos. La adopción de la fertilización azufrada creció marcadamente en ésta región y simultáneamente aumentó la cantidad de publicaciones científicas en el tema. Sin embargo, existe una brecha de conocimiento sobre la fertilización con azufre elemental (AE) y su efectividad agronómica relativa a fuentes azufradas solubles. Los fertilizantes sulfatados sólidos son, con creces, las fuentes de S más utilizadas en la Región Pampeana aunque la aplicación de fuentes líquidas se incrementó en los últimos tiempos. En términos generales, se ha reportado similar efectividad agronómica entre fuentes sulfatadas. Asimismo, se ha observado similar efectividad agronómica entre el AE micronizado y fuentes sulfatadas en diferentes cultivos, con la excepción de condiciones sitio-específicas donde las fuentes sulfatadas pueden presentar una mejor performance. Esta revisión contribuye a sintetizar el conocimiento vigente sobre tecnología de fertilización azufrada y puede resultar de interés para establecer necesidades de investigación en este tema

Temperature-Driven Developmental Modulation of Yield Response to Nitrogen in Wheat and Maize

Nitrogen management is central to the economic and environmental dimensions of agricultural sustainability. Yield response to nitrogen fertilisation results from multiple interacting factors. Theoretical frameworks are lagging for the interaction between nitrogen and air temperature, the focus of this study. We analyse the relation between yield response to nitrogen fertiliser and air temperature in the critical period of yield formation for spring wheat in Australia, winter wheat in the US, and maize in both the US and Argentina. Our framework assumes (i) yield response to nitrogen fertiliser is primarily related to grain number per m2, (ii) grain number is a function of three traits: the duration of the critical period, growth rate during the critical period, and reproductive allocation, and (iii) all three traits vary non-linearly with temperature. We show that “high” nitrogen supply may be positive, neutral, or negative for yield under “high” temperature, depending on the part of the response curve captured experimentally. The relationship between yield response to nitrogen and mean temperature in the critical period was strong in wheat and weak in maize. Negative associations for both spring wheat in Australia and winter wheat with low initial soil nitrogen ( 120 kg N ha-1) that favoured grain number and compromised grain fill, the relation between yield response to nitrogen and temperature was positive for winter wheat. The framework is particularly insightful where data did not match predictions; a non-linear function integrating development, carbon assimilation and reproductive partitioning bounded the pooled data for maize in the US and Argentina, where water regime, previous crop, and soil nitrogen overrode the effect of temperature on yield response to nitrogen fertilisation.Fil: Sadras, Victor O.. University of Adelaide; Australia. South Australian Research And Development Institute; AustraliaFil: Giordano, Nicolas. Kansas State University; Estados UnidosFil: Correndo, Adrian. Kansas State University; Estados UnidosFil: Cossani, C. Mariano. University of Adelaide; Australia. South Australian Research And Development Institute; AustraliaFil: Ferreyra, Juan M.. No especifíca;Fil: Caviglia, Octavio Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Entre Ríos; ArgentinaFil: Coulter, Jeffrey A.. University of Minnesota; Estados UnidosFil: Ciampitti, Ignacio Antonio. Kansas State University; Estados UnidosFil: Lollato, Romulo P.. Kansas State University; Estados Unido

Early-season plant-to-plant spatial uniformity can affect soybean yields

Increased soybean (Glycine max L. Merril) seed costs have motivated interest in reduced seeding rates to improve profitability while maintaining or increasing yield. However, little is known about the effect of early-season plant-to-plant spatial uniformity on the yield of modern soybean varieties planted at reduced seeding rates. The objectives of this study were to (i) investigate traditional and devise new metrics for characterizing early-season plant-to-plant spatial uniformity, (ii) identify the best metrics correlating plant-to-plant spatial uniformity and soybean yield, and (iii) evaluate those metrics at different seeding rate (and achieved plant density) levels and yield environments. Soybean trials planted in 2019 and 2020 compared seeding rates of 160, 215, 270, and 321 thousand seeds ha−1 planted with two different planters, Max Emerge and Exact Emerge, in rainfed and irrigated conditions in the United States (US). In addition, trials comparing seeding rates of 100, 230, 360, and 550 thousand seeds ha−1 were conducted in Argentina (Arg) in 2019 and 2020. Achieved plant density, grain yield, and early-season plant-to-plant spacing (and calculated metrics) were measured in all trials. All site-years were separated into low- (2.7 Mg ha−1), medium- (3 Mg ha−1), and high- (4.3 Mg ha−1) yielding environments, and the tested seeding rates were separated into low ( 300 seeds m−2) levels. Out of the 13 metrics of spatial uniformity, standard deviation (sd) of spacing and of achieved versus targeted evenness index (herein termed as ATEI, observed to theoretical ratio of plant spacing) showed the greatest correlation with soybean yield in US trials (R2 = 0.26 and 0.32, respectively). However, only the ATEI sd, with increases denoting less uniform spacing, exhibited a consistent relationship with yield in both US and Arg trials. The effect of spatial uniformity (ATEI sd) on soybean yield differed by yield environment. Increases in ATEI sd (values > 1) negatively impacted soybean yields in both low- and medium-yield environments, and in achieved plant densities below 200 thousand plants ha−1. High-yielding environments were unaffected by variations in spatial uniformity and plant density levels. Our study provides new insights into the effect of early-season plant-to-plant spatial uniformity on soybean yields, as influenced by yield environments and reduced plant densities.Fil: Pereyra, Valentina M.. Kansas State University; Estados UnidosFil: Bastos, Leonardo M.. University of Georgia; Estados UnidosFil: Froes de Borja Reis, André. State University of Louisiana; Estados UnidosFil: Melchiori, Ricardo J. M.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Paraná; ArgentinaFil: Maltese, Nicolás Elías. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Entre Ríos. Facultad de Ciencias Agropecuarias; ArgentinaFil: Appelhans, Stefania Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Entre Ríos. Facultad de Ciencias Agropecuarias; ArgentinaFil: Vara Prasad, P. V.. Kansas State University; Estados UnidosFil: Wright, Yancy. No especifíca;Fil: Brokesh, Edwin. Kansas State University; Estados UnidosFil: Sharda, Ajay. Kansas State University; Estados UnidosFil: Ciampitti, Ignacio Antonio. Kansas State University; Estados Unido

Winter Wheat Yield Response to Plant Density as a Function of Yield Environment and Tillering Potential: A Review and Field Studies

Wheat (Triticum aestivum L.) grain yield response to plant density is inconsistent, and the mechanisms driving this response are unclear. A better understanding of the factors governing this relationship could improve plant density recommendations according to specific environmental and genetics characteristics. Therefore, the aims of this paper were to: i) execute a synthesis-analysis of existing literature related to yield-plant density relationship to provide an indication of the need for different agronomic optimum plant density (AOPD) in different yield environments (YEs), and ii) explore a data set of field research studies conducted in Kansas (USA) on yield response to plant density to determine the AOPD at different YEs, evaluate the effect of tillering potential (TP) on the AOPD, and explain changes in AOPD via variations in wheat yield components. Major findings of this study are: i) the synthesis-analysis portrayed new insights of differences in AOPD at varying YEs, reducing the AOPD as the attainable yield increases (with AOPD moving from 397 pl m-2 for the low YE to 191 pl m-2 for the high YE); ii) the field dataset confirmed the trend observed in the synthesis-analysis but expanded on the physiological mechanisms underpinning the yield response to plant density for wheat, mainly highlighting the following points: a) high TP reduces the AOPD mainly in high and low YEs, b) at canopy-scale, both final number of heads and kernels per square meter were the main factors improving yield response to plant density under high TP, c) under varying YEs, at per-plant-scale, a compensation between heads per plant and kernels per head was the main factor contributing to yield with different TP.Fil: Bastos, Leonardo M.. Kansas State University; Estados UnidosFil: Carciochi, Walter Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Kansas State University; Estados UnidosFil: Lollato, Romulo P.. Kansas State University; Estados UnidosFil: Jaenisch, Brent R.. Kansas State University; Estados UnidosFil: Rezende, Caio R.. Kansas State University; Estados UnidosFil: Schwalbert, Rai. Kansas State University; Estados UnidosFil: Vara Prasad, P.V.. Kansas State University; Estados UnidosFil: Zhang, Guorong. Kansas State University; Estados UnidosFil: Fritz, Allan K.. Kansas State University; Estados UnidosFil: Foster, Chris. John Deer; Estados UnidosFil: Wright, Yancy. John Deer; Estados UnidosFil: Young, Steven. John Deer; Estados UnidosFil: Bradley, Pauley. John Deer; Estados UnidosFil: Ciampitti, Ignacio Antonio. Kansas State University; Estados Unido

Predicting soil test phosphorus decrease in non-P-fertilized conditions

Monitoring the availability of phosphorus (P) in soil under continuous cropping facilitates finding deficiency in crops and contributes to improving crop growth and nutrient management models. Soil P availability for crops is usually estimated by soil test P (STP), such as Bray-1. This is widely used in the Americas. The relationship between the decrease of STP Bray-1 and cumulative removal of P was evaluated in non-P-fertilized areas in long-term studies. This removal was the sum of annual P removal over the study period as P exported in grains/crop outside the soil. The objectives were to: (a) quantify changes in STP as a function of cumulative P removal, (b) assess the relationship between relative decrease rate of STP and soil variables as well as annual removal of P by crops, and (c) develop a model to predict decrease of STP Bray-1. Exponential decay functions were used to describe annual cumulative removal of P and STP from soil over time for 12 long-term studies where no addition of P fertilizer was carried out. Changes in the relative rate of decrease of STP, relative to the initial STP Bray-1 value at the onset of the experiment, were predicted by the ratio of soil organic matter to clay and silt and the average annual P removal by exponential decay (R2adj = 0.64; RMSE = 3.2 mg kg−1). We propose this predictive model as suitable to provide estimates of the relative decrease rate of STP by Bray-1 and thereby improve management of P for optimizing crop yield. Highlights: STP Bray-1 decrease and cumulative P removal were related by exponential decay functions. Relative decrease rate of STP Bray-1 was related to SOM/(clay+silt) ratio and annual P removal. A predictive model of the relative decrease rate of STP Bray-1 was fitted and validate. Our model is a useful tool to help predict soil P availability and nutrient management.Fil: Appelhans, Stefania Carolina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Paraná; Argentina. Universidad Nacional de Entre Ríos; Argentina. Kansas State University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carciochi, Walter Daniel. Kansas State University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Correndo, Adrian. Kansas State University; Estados UnidosFil: Gutiérrez Boem, Flavio Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; ArgentinaFil: Salvagiotti, Fernando. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Oliveros; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garcia, Fernando Oscar. International Plant Nutrition Institute; ArgentinaFil: Melchiori, Ricardo J.M.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Paraná; ArgentinaFil: Barbagelata, Pedro Aníbal. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Paraná; Argentina. Universidad Nacional de Entre Ríos; ArgentinaFil: Ventimiglia, Luis A.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Norte. Estacion Experimental Agropecuaria Pergamino. Agencia de Extension Rural 9 de Julio.; ArgentinaFil: Ferraris, Gustavo Nestor. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Norte. Estación Experimental Agropecuaria Pergamino; ArgentinaFil: Vivas, Hugo S.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Caviglia, Octavio Pedro. Universidad Nacional de Entre Ríos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ciampitti, Ignacio Antonio. Kansas State University; Estados Unido

Defining optimal soybean seeding rates and associated risk across North America

Soybean [Glycine max (L.) Merr.] seeding rate research across North America is typically conducted in small geo-political regions where environmental effects on the seeding rate × yield relationship are minimized. Data from 211 individual field studies (∼21,000 data points, 2007–2017) were combined from across North America ranging in yield from 1,000– 7,500 kg ha−1. Cluster analysis was used to stratify each individual field study into similar environmental (soil × climate) clusters and into high (HYL), medium (MYL), and low (LYL) yield levels. Agronomically optimal seeding rates (AOSR) were calculated and Monte Carlo risk analysis was implemented. Within the two northern most clusters the AOSR was higher in the LYL followed by the MYL and then HYL. Within the farthest south cluster, a relatively small (±15,000 seeds ha−1) change in seeding rate from the MYL was required to reach the AOSR of the LYL and HYL, respectively. The increase in seeding rate to reach the LYL AOSR was relatively greater (5x) than the decrease to reach the HYL AOSR within the northern most cluster. Regardless, seeding rates below the AOSR presented substantial risk and potential yield loss, while seeding rates above provided slight risk reduction and yield increases. Specific to LYLs and MYLs, establishing and maintaining an adequate plant stand until harvest maximized yield regardless of the seeding rate, while maximizing seed number was important with lower seeding rates. These findings will help growers manage their soybean seed investment by adjusting seeding rates based upon the productivity of the environment.Fil: Gaspar, Adam P.. Dow Agrosciences Argentina Sociedad de Responsabilidad Limitada.; ArgentinaFil: Mourtzinis, Spyridon. University of Wisconsin; Estados UnidosFil: Kyle, Don. Dow Agrosciences Argentina Sociedad de Responsabilidad Limitada.; ArgentinaFil: Galdi, Eric. Dow Agrosciences Argentina Sociedad de Responsabilidad Limitada.; ArgentinaFil: Lindsey, Laura E.. Ohio State University; Estados UnidosFil: Hamman, William P.. Ohio State University; Estados UnidosFil: Matcham, Emma G. University of Wisconsin; Estados UnidosFil: Kandel, Hans J.. North Dakota State University; Estados UnidosFil: Schmitz, Peder. North Dakota State University; Estados UnidosFil: Stanley, Jordan D.. North Dakota State University; Estados UnidosFil: Schmidt, John P.. Dow Agrosciences Argentina Sociedad de Responsabilidad Limitada.; ArgentinaFil: Mueller, Daren S.. University of Iowa; Estados UnidosFil: Nafziger, Emerson D.. University of Illinois; Estados UnidosFil: Ross, Jeremy. University of Arkansas for Medical Sciences; Estados UnidosFil: Carter, Paul R.. Dow Agrosciences Argentina Sociedad de Responsabilidad Limitada.; ArgentinaFil: Varenhorst, Adam J.. University of South Dakota; Estados UnidosFil: Wise, Kiersten A.. University of Kentucky; Estados UnidosFil: Ciampitti, Ignacio Antonio. Kansas State University; Estados UnidosFil: Carciochi, Walter Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Kansas State University; Estados UnidosFil: Chilvers, Martin I.. Michigan State University; Estados UnidosFil: Hauswedell, Brady. University of South Dakota; Estados UnidosFil: Tenuta, Albert U.. University of Guelph; CanadáFil: Conley, Shawn P.. University of Wisconsin; Estados Unido