Abstract
The Northeast China Plain (NECP) is one of the main maize (Zea mays L.) production regions in China but is now subject to drought because of climate change and a rain-fed cultivation system. A two-year experiment was conducted in a typical maize cultivation region in the NECP to investigate the responses of plant physiological factors and evapotranspiration (ET) to water stresses at different growth stages. Results show that the responses of plant physiological factors to water stress can be divided into three levels based on soil water content (SWC) in the main root zone: when SWC was greater than 0.22 cm3/cm3 (equivalent to 62% field capacity (FC)), stomatal conductivity (gs) and ET reached their highest values, and the canopy temperature (Tc) was close to the air temperature; when SWC was within 0.15-0.22 cm3/cm3 (43%-62% FC), the gs and ET decreased, and Tc increased as SWC decreased; and when SWC was lower than 0.15 cm3/cm3 (<43% FC), gs and ET reached their lowest values and Tc was greater than 1.2 times the air temperature. The ratio of canopy temperature to air temperature (RT), is closely related to stomatal conductivity and soil water content, and especially linearly related to crop water stress index (CWSI), and can be used as an alternative to CWSI for evaluating maize water stress because of easily data achieving and simple calculation processes. In a conclusion, RT of 1.2 can be used as an index to identify a severe water stress status, and maintaining SWC greater than 60% FC at the heading and grain-filling stages is important for supporting maize normal ET and growth in the study region. Keywords: water stress, drought indices, canopy temperature, crop evapotranspiration, stoma conductivity, maize, soil water DOI: 10.25165/j.ijabe.20211402.5289 Citation: Liu H J, Gao Z Z, Zhang LW, Liu Y. Stomatal conductivity, canopy temperature and evapotranspiration of maize (Zea mays L.) to water stress in Northeast China. Int J Agric & Biol Eng, 2021; 14(2): 112–119.
Highlights
The Northeast China Plain (NECP) includes Liaoning Province, Jilin Province and Heilongjiang Province and is one of main grain production regions in China
Results show that the responses of plant physiological factors to water stress can be divided into three levels based on soil water content (SWC) in the main root zone: when SWC was greater than 0.22 cm3/cm3 (equivalent to 62% field capacity (FC)), stomatal conductivity and ET reached their highest values, and the canopy temperature (Tc) was close to the air temperature; when SWC was within 0.15-0.22 cm3/cm3 (43%-62% FC), the gs and ET decreased, and Tc increased as SWC decreased; and when SWC was lower than 0.15 cm3/cm3 (
RT of 1.2 can be used as an index to identify a severe water stress status, and maintaining SWC greater than 60% FC at the heading and grain-filling stages is important for supporting maize normal ET and growth in the study region
Summary
The Northeast China Plain (NECP) includes Liaoning Province, Jilin Province and Heilongjiang Province and is one of main grain production regions in China. The high maize grain production in the NECP is the basis for food security in China. Because of plentiful precipitation and radiation in NECP, most maize fields have no irrigation systems, and the traditional cropping system for maize is rainfed[2,3]. In this case, maize production in the NECP is subject to climate change[3,4,5,6]. In 2000, 2007 and 2009, fields in the NECP that suffered from drought totaled 9.3, 11.6 and 9.4 million hm and correspondingly resulted in grain yield reductions of 38.0%, 32.6%, and 22.2%, respectively[10]. Accurate and timely identification of water stress for maize is important for choosing methods to reduce the impact of drought on crop growth and yield
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