Location: Soil and Water Management ResearchTitle: Modeling cotton growth and yield response to irrigation practices for thermally limited growing seasons in Kansas
|Baumhardt, Roland - Louis|
|HAAG, LUCAS - Kansas State University|
|LAMM, FREDDIE - Kansas State University|
Submitted to: Irrigation Association Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/10/2020
Publication Date: 11/30/2021
Citation: Baumhardt, R.L., Haag, L.A., Gowda, P.H., Schwartz, R.C., Marek, G.W., Lamm, F.R. 2021. Modeling cotton growth and yield response to irrigation practices for thermally limited growing seasons in Kansas. In: Proceedings of the 6th Decennial National Irrigation Symposium. ASABE/IA National Irrigation Symposium and Show, December 6-10, 2021, San Diego, California. Paper No. 20-087.
Interpretive Summary: Western Kansas irrigation draws most of its water from the non-recharging Ogallala Aquifer and both water tables and pump yields are declining. Depleting the Ogallala Aquifer will significantly reduce irrigated farming there, but scientists from Kansas and the ARS in Bushland, Texas, researched deficit irrigation of drought tolerant cotton to increase aquifer longevity. Cotton yield response to planting dates, and irrigation rates and times was simulated at Colby, Tribune, and Garden City, Kansas. Yield and water use efficiency decreased with late planting, high site elevation and northern latitude due to lower growing season energy. Simulated cotton yield improved with higher irrigation amounts and rates where seasonal energy was adequate. Net lint yield by split pivot irrigation increased at the lower and more southern Garden City site, but elsewhere, cotton was not well suited as a crop for western Kansas.
Technical Abstract: The western Great Plains precipitation of approximately 450 mm is supplemented with irrigation to meet crop evapotranspiration (ETc) demand. Irrigation from the non-recharging Ogallala Aquifer may be prolonged with drought tolerant crops like cotton [Gossypium hirsutum (L.)] or split center pivot management. Our objective was to compare cotton yield response to emergence date and irrigation capacity and application period for south, central, and northwestern Kansas and evaluate fixed water resource applied to split center pivot portions at different rates. We used actual 1961-2000 location weather with the GOSSYM crop growth model to calculate yields of cotton emerging on day 145, 152, and 159 for all irrigation duration (0, 4, 6, 8, and 10-weeks) and capacity (2.5, 3.75, and 5.0-mm d-1) combinations. Simulated cotton lint yield and water use efficiency (WUE) decreased with emergence delays and higher location elevation or latitude that limits growing season energy. Yield and WUE increased (P=0.05) with increasing irrigation capacity but not for application durations >6 -weeks because progressively fewer fruiting forms matured. No water concentrating split center pivot irrigation strategies increased net yields or advanced maturation to adapt cotton production as an alternative crop in central or northwestern Kansas. The numerically larger overall net lint yield for concentrated irrigation strategies at the southwest Kansas location (Garden City) was not significant. Based on simulated uniform or split pivot deficit irrigated lint yields, we conclude that cotton is poorly suited as an alternative crop for central and north western Kansas because of limited growing season energy.