Evaluation of Infrared Canopy Temperature Data in Relation to Soil Water-Based Irrigation Scheduling in a Humid Subtropical Climate

Abstract

HighlightsCorn response to irrigation was influenced by the precipitation distribution in 2018 and 2019, and that impacted the response of CWSI as an irrigation scheduling signaling method.CWSI was sensitive to changes in soil water storage, increasing due to crop evapotranspiration and decreasing after a precipitation or irrigation event.In 2018, both seasonal CWSI and yield were not different among the irrigation treatments, while in 2019, seasonal CWSI and yield were all statistically different among the treatments evaluated.Post analysis of canopy and air temperature indicated that the temperature-time threshold (TTT) method might not appropriately signal crop water stress in a humid environment.Abstract. Irrigation scheduling based on the crop water stress index (CWSI) and temperature-time threshold (TTT) methods is promising for semi-arid and arid climates. The objective of this study was to investigate if CWSI and TTT methods could be used as irrigation signaling tools for a humid environment in the southeastern U.S. Corn canopy temperature data were collected in Alabama in 2018 and 2019 using infrared leaf temperature sensors on a fully irrigated treatment and on two limited irrigation treatments. A set of three soil water sensors installed at 0.15, 0.3, and 0.6 m soil depth were used to prescribe irrigation time and amount. CWSI was sensitive to precipitation, irrigation, and plant water uptake. No statistical differences in CWSI or yield among the three irrigation levels were found in 2018 when precipitation was well distributed during the season. In contrast, during 2019 both CWSI and yield differed significantly among the three irrigation treatments. Precipitation events in 2019 were sparse compared to 2018; therefore, irrigation promoted greater differences in water availability between treatments. Inconsistencies observed in potential irrigation signaling using the TTT method with or without the inclusion of a limiting relative humidity algorithm indicate that the TTT method may not be a reliable irrigation signaling tool for humid environments. Keywords: Corn yield, Crop water stress index, Irrigation scheduling, Limiting relative humidity, Soil water depletion, Temperature-time threshold.

Beyond 2020, Vision of the Future: Selected Papers from the Sixth Decennial National Irrigation Symposium

“…Advances in irrigation technology [e.g., sensors, irrigation controllers, unmanned aerial systems (UAS)] and its adoption and the availability of innovative research, extension, and education programs in irrigation science were key factors in the progress of irrigation management in the U.S. during the past decade. Seven journal articles from this ASABE Special Collection are discussed in this section, but ten additional articles (Andrade et al, 2020a(Andrade et al, , 2020bCardenas et al, 2020;Conger and Dukes, 2020;Dukes, 2020;Evett et al, 2020b;Lena et al, 2020;O'Shaughnessy et al, 2020;Stone et al, 2020;Sui et al, 2020) discussed in other sections of this article easily overlap with this topic.…”

“…Nearly 30% of the total irrigated land area in the U.S. is located in the eastern humid states, and the area continues to increase (USDA-NASS, 2018). Overall, eight journal articles for this ASABE Special Collection were related to agricultural irrigation in the humid region, with three articles specifically discussed in this section (Leib et al, 2020;Lena et al, 2020;Reinhart et al, 2020). The other five articles were discussed in the Technology and Innovation section (Chiu and Reba, 2020;Henry, et al, 2020;Lo et al, 2020), the Irrigation Systems section (Reba and Massey, 2020), and the Irrigation Management section (Zamora-Re et al, 2020).…”

“…Plant water stress criteria [CWSI and temperature-time threshold (TTT)] were evaluated in a humid subtropical climate for irrigated corn production in Alabama (Lena et al, 2020). In a season with more sparse rainfall events, both CWSI and corn yield were significantly affected by irrigation treatment, but not so in a season with more evenly distributed rainfall.…”

A comparison of precision and conventional irrigation in corn production in Southeast Alabama

“…Irrigation water is key to crop production due to its contribution to attainable yield, role on nutrient uptake (Sigua et al, 2017), and mitigation of heat and water stress to the crop (Lena et al, 2020;Mondaca-Duarte et al, 2020). Even with the importance of irrigation in agriculture, there are still many challenges associated with irrigation adoption, such as competition for freshwater with urban areas and industry, the increased irrigation demand for bioenergy crops, and lack of adoption of efficient irrigation systems and best irrigation management practices (USDA-ERS, 2019;WWAP, 2018).…”

“…Some irrigation specialists consider MAD as 50% but this value should be adjusted based on crop type, climate, soil type, and the irrigator's knowledge (Rogers, 2012). Soil sensor data allows the irrigation operator to track SWS so it can be maintained above the irrigation threshold (MAD level) to prevent crop water stress and subsequently yield losses (Lena et al, 2020;Rogers, 2012). Several authors have reported multiple benefits from the use of this approach.…”