Effects of potassium application on growth, yield, and quality of dryland cotton

Authors: KOMMINENI, VARSHITH - South Dakota State University; Bhandari, Ammar

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2024
Publication Date: 8/31/2024
Citation: Kommineni, V., Bhandari, A.B. 2024. Effects of potassium application on growth, yield, and quality of cotton varieties in dryland South Texas. Agronomy Journal. https://doi.org/10.1002/agj2.21664.
DOI: https://doi.org/10.1002/agj2.21664

Interpretive Summary: Potassium (K) is an essential plant macronutrient that plays a crucial role in different physiological processes such as photosynthesis, carbohydrate metabolism, osmotic potential maintenance, enzyme activation, elongation of pollen tubes, and fiber growth and development in cotton (Gossypium hirsutum L.). Lack of potassium during its growing season can lower lint yield and produce inferior lint quality. Some studies in the past have reported inconsistent and mixed results with applied potassium fertilizers in soils to cotton yield and lint quality. Therefore, studies were necessary to quantify the effect of potassium fertilizer application in broad soil test levels and growing conditions. The results indicated that the cotton plant height increased in 2020 and 2021 with potassium fertilizer application rates compared to the control. The potassium application increased cotton canopy by 39% in 2021 compared to 2020. Potassium application increased lint yield by 9-25% in 2020 and 4-17% in 2021 compared to control. This indicates that even if the soil already contains sufficient K levels, adding more K can still help improve seed and lint yield in dryland production systems. In 2020, the cotton fiber staple length and color grade increased with potassium application compared to control. The cotton varieties impacted Col-Rd and Col-b in 2020 and 2021, indicating variety selection should be part of any potassium fertilization program. This study can be helpful for producers in dryland farming systems to adjust their potassium application in cotton production. This study will also help researchers and stakeholders reevaluate the current potassium fertilization recommendations and the selection of cotton varieties in dryland farming systems.

Technical Abstract: Potassium (K) deficiency symptoms have recently been observed in cotton (Gossypium hirsutum L.) growing areas, including South Texas. The study's objective was to determine and compare the effect of K fertilizer applications on cotton growth, yield, and quality. Three cotton varieties studied were NG 5711 B3XF, PHY 480 W3FE, and FM 1953GLTP. Granular K fertilizer was surface broadcast and incorporated one week before planting at 34, 50, and 67 Kg ha-1. Eight plants were randomly selected to measure the plant height (PH) and canopy from 30 to 105 days after planting. The cotton PH increased by 13%, 17%, and 12% in 2020 and by 6%, 4%, and 8% in 2021 with 34, 50, and 67 kg ha-1 K fertilizer application rates compared to control. The K application increased cotton canopy by 39% in 2021 compared to 2020. K application at 50 kg ha-1 yielded significantly more cotton yield than the control in 2020. The cotton lint yield increased by 25%, 34%, 9% in 2020 and by 4%, 17%, and 11% in 2021 with 34, 50, and 67 kg ha-1 K fertilizer application rates than control. The cotton fiber staple length and color grade increased significantly with the 50 kg ha-1 K application rate than the control in 2020. Varieties significantly impacted Col-Rd and Col-b in 2020 and 2021. This study can be used as a reference for future studies on the effects of K fertilization on cotton yield and quality in dryland farming systems.