Quantify the effects of potassium nutrition on corn (Zea mays L.) physiology and growth for modeling

Authors: THENVEETTIL, NAFLATH - Mississippi State University; Reddy, Krishna; REDDY, RAJA - Mississippi State University

Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/18/2024
Publication Date: 6/21/2024
Citation: Thenveettil, N., Reddy, K.N., Reddy, R.K. 2024. Quantify the effects of potassium nutrition on corn (Zea mays L.) physiology and growth for modeling. Agriculture. 14:968. https://doi.org/10.3390/agriculture14070968.
DOI: https://doi.org/10.3390/agriculture14070968

Interpretive Summary: Potassium (K) deficiency in corn is an emerging concern, especially when the crop is exposed to stress conditions. The insufficient replenishment of K in soil heightens the severity. Scientists from Mississippi State University, Mississippi Sate, Mississippi and USDA-ARS, Crop Production Systems Research Unit, Stoneville, Mississippi have investigated corn physiology and growth responses under five levels of potassium concentrations, 100% (control; 193 ppm), 40%, 20%, 5%, and 0%, using modified Hoagland’s nutrient solution imposed at 1st leaf stage and continued until tasseling. The plant growth and development were monitored at different growth stages. The findings of this study underscore the critical role of leaf K levels, particularly when below 1.6%, in significantly impairing photochemical and carbon assimilation processes during corn vegetative growth and development. Notably, reductions in leaf K content led to substantial declines in critical physiological and growth parameters, specifically shoot dry weight. The decrease in intercellular CO2 level is due to both stomatal and non-stomatal limitations. The variations in K supply did not yield significant changes in plant height, root dry weight, or the root-to-shoot ratio. The regression relationship derived from this investigation offers valuable insights that can be integrated into corn models, where leaf K content serves as a pivotal subroutine, enhancing our understanding of corn growth dynamics and contributing to more accurate predictive modeling of corn models such as CERES-Corn and MaizeSim. The functional relationship generated from this study will help improve corn models for field applications.

Technical Abstract: Potassium (K) deficiency in corn is an emerging concern, especially when the crop is exposed to stress conditions. The insufficient replenishment of K in soil heightens the severity. A good K management requires adequate knowledge of its effect on plant growth and physiology. A sunlit growth chamber study was conducted under five levels of potassium concentrations, 100% (control; 193 ppm), 40%, 20%, 5%, and 0%, using modified Hoagland’s nutrient solution imposed at 1st leaf stage and continued until tasseling. The plant growth and development were monitored at different growth stages. Physiological parameters were measured at the tasseling stage. Significant differences (p<0.05 to 0.001) in plant growth and physiological parameters were recorded in response to potassium rates. The 0% K treatment reduced the leaf K content and addition of leaf area day-1 by 85% and 8%, respectively, compared to the control. The rate of total biomass accumulation reduced to 5.4 g day-1 under 0% K compared to 7.7 g day-1 under the control. The root-to-shoot ratio increased to 0.33 at 5% K compared to 0.16 at the control treatment. The photosynthetic rate was reduced by 30% and 35% under 5% and 0% potassium concentrations, respectively, com-pared to the control. High K deficiency decreased the stomatal conductance by 60% over control, lowering the internal CO2 level and transpiration. Linear and quadratic relationships were observed between leaf K content and electron transport rate (R2 = 0.98) and transpiration rate (R2 = 0.96), respectively. The functional relationship generated from this study will help improve corn models for field applications.