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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Soil and Water Management Research » Research » Publications at this Location » Publication #342044
Research Project: Precipitation and Irrigation Management to Optimize Profits from Crop Production

Location: Soil and Water Management Research

Title: Deficit irrigation effects on yield and yield components of grain sorghum

Author
item BELL, JOURDAN - Texas A&M Agrilife
item Schwartz, Robert
item MCINNES, KEVIN - Texas A&M University
item HOWELL, TERRY - Retired ARS Employee
item MORGAN, CHRISTINE - Texas A&M Agrilife

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2018
Publication Date: 3/22/2018
Citation: Bell, J.M., Schwartz, R.C., McInnes, K.J., Howell, T.A., Morgan, C.L. 2018. Deficit irrigation effects on yield and yield components of grain sorghum. Agricultural Water Management. 203:289-296.

Interpretive Summary: Development of sustainable and efficient irrigation strategies is a priority for agricultural producers faced with water shortages. A promising management strategy for improving water use efficiency is managed deficit irrigation (MDI). Under MDI the crop is not fully irrigated (FI), but proportionately greater irrigation is applied during the reproductive stages. In contrast, deficit irrigation (DI) consists of irrigating at a fraction of the full irrigation requirement throughout the growing season. Soil water use and yield of grain sorghum were evaluated in the High Plains of Texas, USA under FI, DI, and MDI. Grain yields of FI sorghum averaged 59 bushels/acre greater than sorghum receiving limited irrigation (DI + MDI). However, greater yield under FI came at a cost of 7.6 inches of additional irrigation per year. In contrast, MDI averaged 25 bushels/acre more than DI yields using only 1.5 inches of additional irrigation. Yield was stabilized under MDI by maintaining a high number of seeds per panicle. The results demonstrated that the water use efficiency of grain sorghum is not reduced under MDI compared with FI in most cropping seasons. While FI provides the greatest opportunity to reduce production risks, if irrigation water is limiting, MDI involves less risk compared with DI.

Technical Abstract: Development of sustainable and efficient irrigation strategies is a priority for producers faced with water shortages. A promising management strategy for improving water use efficiency (WUE) is managed deficit irrigation (MDI), which attempts to optimize yield and WUE by synchronizing crop water use with the crop’s reproductive stages. In comparison, deficit irrigation (DI) is applied at a fraction of the full (FI) irrigation requirement. Soil water use and grain yield of grain sorghum [Sorghum bicolor (L.) Moench] were evaluated in the High Plains of Texas, USA under three irrigation strategies: FI, DI, and MDI. Grain yields of FI sorghum averaged 3.7 Mg ha-1 greater (p < 0.001) than DI sorghum in all years. However, MDI yields averaged 1.6 Mg ha-1 more than DI yields, which was significant in 2010 and 2012 (p = 0.006). The WUE of FI sorghum was significantly greater than MDI in 2012 (p =0.003) and DI in 2010 and 2012 (p = 0.001) demonstrating that limiting water did not reduce WUE in two of the three years. Results suggest that WUE’s of grain sorghum are not compromised under MDI compared with FI in most cropping seasons. While FI provides the greatest opportunity to reduce production risks through increased yield, if irrigation water is limiting, MDI provides less risk than DI due to its ability to maintain yield and WUE. Yield was stabilized in all years by increasing seed panicle-1 under MDI, which was supportive of concentrating irrigation water between growing point differentiation and half bloom to maintain ovules.