Crop Physiology
Cropping Systems
From planting to harvest, our team works on every step of the process
Current research projects in this area:
Locations: Wamego, KS
Ph.D. Students - Francisco Palmero
Cropping Systems
Dissecting the early-season dry matter and N uptake ability of AG099 hybrids in the field
We are exploring the mechanisms explaining the early-season dry matter and N uptake ability of new transgenic corn hybrids. It was already reported that these transgenic plants increased N-uptake ability during vegetative stages in field experiments.
Currently, we are focusing on whether this elevated N acquisition capacity is determined by the leaf growth or by the root system size, and if so, how early in the season the differences are being expressed in the field.
The specific goals of my project are to:
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Quantify early-season shoot: root ratio to understand C economy and changes in dry matter allocation.
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Investigate the temporal changes on SLN (canopy profile) to explore the initial timing for changes in N allocation.
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Determine ear N content from late vegetative to initiation of kernel set.
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Quantify N recovery efficiency before flowering (V2-R1) and total season (V2-R6) using labeled isotopic N (15N).
Project funded by Corteva
Identification of the critical period for seed yield determination in mungbean (Vigna radiata)
Post Doctoral Researcher - Victor Gimenez
Cropping Systems
Locations: Manhattan, KS
Project funded by Department of Kansas
Diversified cropping systems come with fewer management risks, bring economic benefits, and contribute to the sustainability of crop systems. Therefore, it is crucial to assess new crop options for rotation. Mungbean (Vigna radiata) emerges as a summer crop alternative. This warm-season legume, like soybean, fixes atmospheric nitrogen and supports soil health. With high grain protein content, heat, drought tolerance, and a short growth cycle, mungbean is a promising alternative for double cropping after winter wheat or canola harvest.
When considering the integration of a crop into rotation, understanding the key stages for yield determination is critical. All management practices, such as planting date, density, genotype selection, and nutrient/water management, should aim to maximize crop growth during these stages to ensure optimal yield.
Hence, this study aims to: (i) Identify the critical period for mungbean yield determination. (ii) Define the most significant numerical and physiological components in determining mungbean yield.
Soybeans can adjust the variation in changes in stand density in order to compensate for maximizing seed yield. However, the extent of the impact of the spatial (spacing between consecutive plants within a row) and the temporal variability (time to emergence) on the plant-to-plant uniformity and final seed yield are still unclear.
The importance of early-season stand uniformity and the use of precision planting system technologies become even more relevant under low plant densities in order to maximize yield, improving seed savings, and increasing farming profits.
Therefore, the objectives of this project study were to:
1) Assess the effect of plant density in yield at canopy-scale
2) Evaluate the effect of spatio-temporal variability for both uniformity and yield at plant-level affected by planter technologies and plant densities in two different growing environments.
For more information and the current state of the project, please visit Valentina's website at:
Project funded by John Deere
Locations: Manhattan, KS
Spatio-temporal plant-level uniformity in soybean across different planters and densities
M.S. Student - Valentina Pereyra
Cropping Systems
Previous studies conducted in the US over the last century explored the effects of equidistant plant arrangement on soybean yield, demonstrating a positive effect of equidistant arrangement. Concurrently, breeding endeavors have progressively enhanced soybean compensation over the years. Hence, nowadays exists a significant gap in recent research investigating the benefits of equidistant arrangements.
The study aims to:
i) assess the effects of equidistant versus non-equidistant plant arrangements on soybean yield and seed quality across different regions in the United States (US);
ii) explore potential correlations between alterations in canopy development resulting from different plant arrangements and their influence on yield and seed quality.
Locations: Kansas: Kansas: Topeka & Manhattan.
Mississippi: Starkville & Stoneville.
South Dakota: Aurora & Belleville
M.S. Student -Emmanuela van Versendaal
Cropping Systems
Soybean yield and seed quality in equidistant versus non-equidistant plant arrangements
Project funded by John Deere
The US central Great Plains is the largest growing region of monoculture winter wheat in the world. However, low productivity, yield stagnation, and reduction of water use, altogether with increased susceptibility to climate variability represent a challenge for agricultural producers. A more holistic assessment of the cropping systems should be considered as a critical aspect for developing more sustainable rainfed agricultural systems in this region.
The primary objective of this research project is to evaluate the effects of crop intensification and diversification on different crop rotations, including annual and perennial forages, cover crops, and grain crops, during a 3-year field experiment.
For more information about the current state of the project, please visit Ignacio’s website at:
Exploring alternative crop rotations to continuous winter wheat for agricultural intensification in the US central Great Plains
Ph.D. Student - Ignacio Massigoge
Cropping Systems
Location: Manhattan, KS.
Project funded by the Rainfed Agriculture Innovation Network.
Detecting N deficiency in corn and developing a decision support model for informing N fertilization
M.S. Student - Leonardo Bosche
Cropping Systems
Location: Topeka, KS.
Project funded by John Deere
Nitrogen (N) stands out among all plant nutrients as the primary element that limits yield in corn (Zea mays L.) production systems. To optimize the use of nitrogen and improve nitrogen use efficiency (NUE), it is crucial to gain a deeper understanding of the timing and consequences of N deficiencies in corn.
The development of rapid tools to access the crop N status under field conditions can aid in diagnosing N deficiency and assist farmers not only in effectively managing nitrogen application but also, to promote sustainable farming practices.
My research focuses on nitrogen deficiency in corn and aims to:
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Develop effective strategies to enhance nitrogen use efficiency (NUE).
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Identify suitable sensors to detect and diagnose nitrogen deficiency in corn.
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Pinpoint how late farmers can recover from mild N deficiencies.
Location: Southeast Asia
Post Doctoral Research - Federico Gomez
Cropping Systems
Soil organic carbon (SOC) is one of the main indicators of soil quality; therefore, this resource's degradation is associated with a reduction in crop productivity. Furthermore, the soil has been proposed as a sink for atmospheric C, making it relevant to estimate the C sequestering capacity of soils.
Southeast Asia has shown high rates of deforestation and changes in land use, with a tendency towards more intensive cropping systems dominated by monocultures of rubber and oil palm plantations.
This project involves i) compiling a SOC database from a systematic search of the available scientific literature. ii) assessing land use change and implementing management practices on different cropping systems on SOC content.
Soil organic carbon in cropping systems in Southeast Asia
Unlocking the linkage between breeding and production research for N fixation, protein, and yields
MS Student - Gabriel Hintz
Crop Physiology
Location: Junction City, KS.
Project is funded by Kansas Soybean
This research project aims to address critical issues impacting soybean production in the US by identifying and mitigating nutrient limitations, particularly nitrogen, on yields, developing strategies to enhance protein content, and improving new soybean varieties with high rates of nitrogen fixation. Recognizing the deceleration of soybean yields relative to corn, the study seeks to elucidate the yield-protein tradeoff while enhancing crop productivity and sustainability. By focusing on Biological Nitrogen Fixation (BNF), the project aims to quantify nitrogen fixation in US soybeans, advocating for improved breeding practices to enhance nitrogen fixation in new varieties.
Ultimately, this initiative strives to offer novel insights for augmenting soybean yields, refining seed quality, reducing environmental impacts, and fostering greater profitability for US farmers, especially as soybean yields increase and environmental stressors intensify.
Location: Rio Grande do Sul State (Brazil) and Kansas State (US)
Project is funded by Cooperativa Central Gaucha (CCGL) & Kansas Soybean
MS Student - Gabriel Hintz
Crop Physiology
Enhancing dry-down predictive models
This research project aims to study the grain filling and dry-down processes of diverse soybean genotypes across different planting dates in Rio Grande do Sul, Brazil, and Kansas State, United States. Through field experiments and lab analyses, the project seeks to understand how environmental factors and planting dates influence the development of different soybean varieties. The study aims to enhance predictive models to accurately predict the ideal harvest date based on weather conditions, soil characteristics, and farmer management. The findings will provide valuable insights for optimizing data-driven decision-making through predictive algorithms.
Benchmarking maize-soybean yields in the US Corn Belt
Ph.D. Student - Ignacio Massigoge
Crop Physiology
Project is funded by Project funded by Corteva Agriscience, Kansas Corn and Kansas Soybean.
Maize typically outperforms soybean in terms of yield over a wide range of environmental conditions. This is mainly explained by differences in: i) carbon fixation metabolism (C4 vs. C3); ii) canopy architecture (leaf arrangement and expansion; iii) energy content of both vegetative and reproductive organs; and iv) use of more energy as carbohydrates to sustain nitrogen fixation process for soybeans. However, to the extent of our knowledge, no studies have synthesized existing information to compare maize and soybean yields grown under similar environments over a large spatial scale in recent decades.
The primary objective of this research project is to investigate the relationship between maize and soybean yields grown in similar geography under standard farming practices using data from the Crop Performance Trials for each state in the US Corn Belt.
Previous Projects in this area:
The current state of art of agronomic statistical models focuses on the use of past-season data and static variables, performing mostly ex-post analyses to provide recommendations for future scenarios. However, these models are sometimes difficult to interpret, and lack an integration of probabilistic reasoning to maximize the options for inference and risk assessment.
The main objective of my Ph.D. research is developing data driven forecasts of management effects on maize yields (Zea Mays L.), with a probabilistic approach.
Take the case of targeting the right economic optimum plant density (EOPD) for maize, a critical management decision. Although yield response to density varies depending on the weather conditions during the growing season (just like many other management practices, e.g. Nitrogen feritlization), that decision must be made with minimal information about the seasonal weather conditions. The specific objectives to improve the risk assessment for this agronomic practice are to (i) design a model that describes the yield-to-plant density (herein termed as yield-density) relationship as a function of weather variables, (ii) evaluate the predictive performance and analyze the sources of uncertainty, and (iii) provide probabilistic forecasts for predicting the economic optimum plant density (EOPD).
Developing probabilistic prediction tools to improve maize management
Ph.D. Student - Josefina Lacasa
Crop Physiology
Project funded by Kansas Corn Commission & Corteva Agriscience
A global dataset for nitrogen nutrition index (NNI)
for field crops
A global initiative for expanding the use of critical nitrogen (N) dilution curves for field crops and including N nutrition index (NNI) for diagnosis of plant nutrient status was pursued to provide a foundational database. There is an increasing number of investigations regarding critical N dilution curves under different genotype, environmental and management (GxExM) scenarios. However, those investigations are analyzed independently (e.g. site by site, species by species, variety by variety). Until recently, a quantitative synthesis at global scale is lacking on this topic, which limits the development of more “universal” dilution curves and with a less reliable analysis of the effect of factors determining the characteristics of the N dilution curves. The final dataset contains 4581 observations spanning from 1982 to 2020 and from 13 countries around the globe. This dataset can guide the development of more universal N nutrition recommendations and advance science on understanding the effect of different GxExM scenarios for field crops around the globe.
M.S Student - Emmanuela van Versendaal
Crop Physiology
Project funded by John Deere
Project funded by Corteva Agriscience and the Kansas Corn Commission
Locations: sites in Manhattan, Keats, Buhler, Greensburg, Garden City, Goodland, and Colby.
Ph.D. Rachel Veenstra
Crop Physiology | Extension
Understanding the physiological tillering process in maize in water-limited environments
Tillering is a genetically-influenced environmental plasticity response that has historically been found under great debate among corn producers, agronomists, and researchers. Tillers (commonly “suckers”) are induced by favorable environmental conditions in cereals, but due to relatively late development of tillers in corn, overall productivity contributions are less than in other Poaceae species.
Current research evaluating the overall value of tillers to corn plant productivity is scarce, particularly under water-limited conditions. Because corn planted in water-limited or dryland environments, specifically in western Kansas, is commonly intended for final stands under 20,000 plants ac-1, conditions are prime for tiller development given the use of conducive hybrids. Of particular interest in corn is the effect that tillers have on the productivity of the main stalk (thus their nickname, “suckers”).
Fact-based conclusions regarding tillering implications in modern corn hybrids are elusive. For this reason, the objectives of this study are to
1) quantify relationships between tiller, main plant, and full plant aboveground biomass and yields of corn under various plant density scenarios;
2) identify potential traits, environments, or management strategies responsible for determining these relationships; and
3) create a base framework for predicting tiller development and determining final yield outcomes.
For more information and current state of the project please visit Rachel's website at:
Ph.D. Mario Secchi
Crop Physiology
Locations: South Central and North East, KS
Project funded by John Deere, Corteva Agriscience, and USDA-NIFA.
Winter Canola
Multiple Projects
Canola oil it’s healthy with low saturated fats and it's a big potential source of renewable energy. Besides, this crop is an ideal habitat for honeybees, a blooming canola field could last for up to a month! But Winter Canola production has some challenges, after implanted in the fields, needs to survive the entire winter to keep growing, and produce flowers to convert those flowers efficiently into a huge number of small, tiny oil packages, which are the seeds.
Our research consists of finding the meteorological variables characterizing winter survival and oil production using data from the last 4 decades, in more than 20 states with almost 200 field experiments to define the best suitable potential areas for its production.
After defining the best potential areas, we want to go more into detail and look at the specific period where flowers convert into seeds, and for this, we planted field experiments to follow up the development and dynamics throughout this seed formation period. The oil yield is not constant, and we want to find out what could lead to the ups and downs of that variability.
Finally, based on those complex processes that we study we will simulate with the help of software platforms several possible scenarios for the future.
We expect that our research results will help farmers to make decisions and people from the industry will have a potential area of development for new markets. We think that a critical aspect of our future is on sources of renewable energy as a feedstock for biofuels, and we still need to keep learning about them.
For more information and the current state of the project, please visit Marios's website at:
The KSU crop team, in partnership with the United Soybean Board and a network of US universities, is committed to increasing competitiveness, sustainability, and marketability for US soybean production. In this context, the KSU crop team hosts several projects aiming to improve seed composition quality throughout crop management and plant nutrition.
One of the primary reasons for soybean importance for the livestock industry is because of the relatively high protein concentration and amino acid profile of its seed. Protein and amino acids are carbon-based molecules with at least one nitrogen (N) functional group. Their accumulation into the seeds results from a complex interplay between environmental conditions and genotype but markedly depends on crop N nutritional status. Soybean is an N fixing crop which commonly receives less N-fertilizer input (mineral and organic) than the crop requirements. Most N is supplied thru endosymbiosis between the plant and α-proteobacteria rhizobia group. The N provided by rhizobia will serve as building blocks for the whole plant protein systems such as photosynthesis apparatus and ultimately to the seed contained protein. Therefore, improving protein concentration and the quality of the amino acid profile is achievable by using comprehensive multi-factor crop management and environmental framework.
Recently our research showed not all amino acids have been decreasing at the same rate of protein in US historical genotypes. The bulk N reserve amino acids such as glutamine followed a similar trend of protein, but some essential amino acids increased when compared to the protein. This evidence unleashed potential opportunities to investigate other than genotype aspects undertaking influence in seed amino acid profile. Our ongoing projects include
1) The effect of N and S mineral fertilizer management in the seed composition and interactions to plant C and N acquisition process;
2) How the activity of biological activity along the growing season affects seed composition;
3) Prediction of protein concentration based on environmental and agronomic variables.
For more information and the current state of the project, please visit André's website at:
Post Doctoral Researcher - André Reis
Ecophysiology | Plant Nutrition | Crop management
Project funded by United Soybeans Board
Improving the quality of soybeans seed composition thru crop management
Ph.D. Student - Javier Fernandez
Crop Physiology
Physiological Determinants of Nitrogen Dynamics
in Response to Genotype and Management Interactions in US Maize Hybrids
From all plant nutrients, nitrogen (N) is recognized as the major yield-limiting element in maize (Zea mays L.) production systems. The efficiency of applied N depends on the complex interaction between genotype, environment, and management. Over time, breeding and direct selection for grain yield have been accompanied by a simultaneous increase in both N uptake and utilization efficiency (i.e. grain yield per unit of N absorbed). The understanding of biological processes involved in N absorption and its conversion into yield can help to determine suitable combinations of hybrids and agronomic practices and therefore, assist in future selection strategies in maize.
From a physiological perspective, yield determination could be realized as the outcome of a dynamic function of (i) the amount of assimilates produced by “source” organs via plant growth, and (ii) the capacity to transform them into harvestable yield in the reproductive sink. Such framework laid the foundations for this research study to interpret hybrid performances across different N fertilization strategies in maize (genotype ✕ management).
The primary objectives of this research project are to:
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identify responses on grain yield and recovery efficiency of N to late-season N fertilization across a broad set of agronomic and environmental conditions,
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describe N uptake and allocation dynamics across different N fertilization strategies and genotypes representing different phases of germplasm development, and
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provide a cognitive framework that formalizes the interplay between plant N status and carbohydrates availability to analyze drivers of genetic yield gain in maize.
More about Javier's research:
Post Doctoral Researcher Javier Fernandez
Crop Physiology
Project funded by Fulbright, Corteva Agriscience and the Kansas Corn Commission
Project funded by Fulbright, Corteva Agriscience and the Kansas Corn Commission
This research focuses on the study of nitrogen (N) economy components in corn-soybean systems.
Variability in soil N supply not only exerts influence on yields and N use efficiency (NUE) in corn but also on potential N limitations in soybeans. Yield and NUE improvements linked to enhanced synchrony between plant N demand and supply are likely to be achieved by refining the understanding of key nutrient processes such as N mineralization and biological N fixation (BNF). However, current literature falls short of simultaneous evaluation of these two main N economy components (soil N supply and fixed N) for these major crops that dominate the US Agriculture.
Thus, the main goals of my project are
1) to evaluate corn and soybean yield limitations related to constraints in the availability of N;
2) to explore the effect of soil and weather factors on both soil N supply and biologically-fixed N pools, and
3) to model the BNF in soybean during the cropping season as espoused to the soil N supply.
This project encompasses two different scales of research:
Local-scale: Two corn and soybean studies are planted each year (2019-2020) in Scandia, Kansas (North Central region). Two independent irrigation phases are included as irrigated and rainfed conditions, respectively. Within each phase, corn treatments include five N levels (0, 60, 120, 180, and 240 lb/a), while soybeans follow the rotation on the residues of corn with different N levels. Thus, N fertilization in corn serves not only to explore effects on corn but also on residual effects of the practice on the following soybean. Measurements are focused on providing a characterization of soil fertility (Soil organic matter, pH, soil texture, P, K, cations), soil N supply metrics (residual-N, mineralizable-N), grain yields, seasonal biomass production, maize plant N uptake dynamics, and soybean N uptake and N fixation using the 15N abundance and ureides methods.
Regional-scale: The project also comprises 22 site-years (2019 and 2020), distributed across the US Corn Belt in partnership with Corteva Agriscience. The main goal at this level is to identify soil and weather factors that might drive soil N supply, N fixation, and potential trade-offs. We follow a simple protocol based on three main treatments: i) N-omission corn (0 lb N/ha), ii) non-N-limited corn (280 lb N/a), and iii) a soybean (only inoculated), all with no other nutrients limitations. A less intensive sampling than local scale (due to logistics and costs) is focused on a complete initial soil characterization (general fertility, residual-N, and mineralizable-N) and final residual-N scenario (0-24”) before harvest.
For more information and the current state of the project, please contact Adrian at correndo@ksu.edu
Post Doctoral Research Adrian Correndo
Crop Physiology
Nitrogen economy components
in corn-soybean systems
Project funded by Fulbright, Corteva Agriscience and the Kansas Corn Commission
Physiological changes across historical sorghum hybrids released during the last six decades
Sorghum (Sorghum bicolor L. Moench) is ranked among the top five cereal crops produced in the world. This cereal is grown as commercial grain and forage crop for livestock feed as well as for energy production (ethanol industry). While the United States is the major producer of sorghum in the globe, within the country, the region with the highest production spans from South Dakota to Southern Texas, so called the Great Plains region.
For the last decades, sorghum improvement in the US has been related to targeted modifications in genotype, environment, and management (G × E × M) combinations. Yield gains and related traits have been studied in detail on other cereal crops such as wheat and maize. Authors suggested that the understanding of the physiological traits associated with yield formation plays a key role in the identification of limiting factors and in the development of new strategies for yield improvement. Comparatively, yield improvement in grain sorghum can be assumed to be around 40% due to hybrid improvement and around 60% due to management.
Highlighting the importance of identifying traits associated with yield improvement, this study proposes to characterize changes over time for yield and related physiological traits for sorghum hybrids with different years of release.
More about Paula's research:
MS. Paula Demarco
Crop Physiology | Analytical methods
Project funded by FFAR -Foundation for Food and Agriculture Research- and Corteva Agriscience