Impacts of Mist Spray on Rice Field Micrometeorology and Rice Yield under Heat Stress Condition

Abstract

Heat stress is one of the common agrometeorological hazards in rice production in the middle and lower reaches of the Yangtze River in China. To study the mechanism of mist spray in ameliorating heat stress injury, a field experiment was conducted at Nanjing (China) with an early and a late hybrid rice varieties (Oryza sativa L.). The mist spray treatments were conducted at the flowering period, which were at August 6-10 for early rice variety and September 1-5 for late one. Four treatments at different irrigation times (T1: 08:00; T2: 12:00; T3: 14:00; CK: no mist spray; mist spray amount of 1 L·m−2) were included. The temperature and humidity at the different heights of the rice canopy and the net solar radiation above the canopy were measured. The leaf senescence, chlorophyll content, photosynthetic rate and the yields of the rice were determined. The results showed that mist spray rapidly reduced the temperature and increased the relative humidity in the canopy. The cooling effect was most significant at the top of the canopy and decreased downward from the top of canopy. The duration of the temperature decrease caused by the mist spray was 2 h. Mist spray could lead to an increase in latent heat flux (LE) and a decrease in sensible heat flux (H) in the rice field. The mist spray treatments delayed the senescence of the rice leaves, increased the activity levels of the superoxide dismutase, peroxidase, catalase, and soluble protein, reduced the malondialdehyde content, increased leaf chlorophyll content, photosynthetic rate and yield. The T2 treatment showed the most significant effect against heat stress, with the yield of the two varieties increased 13.7 and 13.6% respectively. Compared with mist spray at 08:00 or 14:00, spraying at 12:00 had the strongest resistance to heat stress in rice field.

Review on Plant Physiology and Crop Modeling for the Response of Rice Crop to Climate Change

“…The moderate increase of nitrogen application and combined application of biochar and phosphorus have also been the major management options to alleviate rice yield losses caused by heat stress at the reproductive stage. Mist spray treatment during the flowering period rapidly reduces temperatures in the rice field, delays leaf senescence, and increases the activities of antioxidant enzymes, thus alleviating HS-caused yield loss (Jiang X et al, 2020). Application of plant hormones and inorganic elicitor molecules to induce short term acclimation response shown as useful for mitigating high temperature stress effects specifically applied at critical growth stage.…”

Energy Balance, Microclimate, and Crop Evapotranspiration of Winter Wheat (Triticum aestivum L.) under Sprinkler Irrigation

“…Irrigation can cool the land surface and increase air humidity in irrigation areas, as found in America [6], China [7,8], and India [9]. Because field microclimate directly influence crop growth, understanding the impact of irrigation on field microclimate could help improve crop growth and irrigation management [10][11][12].…”

“…Sprinkler irrigation is one of the main irrigation methods in the world because of its water saving and enhanced food productivity potential [11,13,14]. Based on the data of the International Commission on Irrigation and Drainage, sprinkler-irrigated areas account for 43% and 10% of the total irrigated area in developed and developing countries, respectively [15].…”

“…orchard at the flowering to fruit set stage, the mean daily canopy temperature during sprinkler irrigation events decreases between 1 and 3 • C, the mean daily relative humidity (RH) increases between 11 and 17%, and the mean daily vapor pressure deficit (VPD) decreases from 3 to 2 kPa [12]. The temperature at the top of the canopy is reduced by 1.1-1.6 • C after mist spraying 1 mm water at the flowering stage of rice (Oryza sativa L.), and this cooling effect lasts for approximately 2 h [11]. Compared with surface irrigation in the winter wheat field, daytime sprinkler irrigation with 50 mm water results in 1.1-2.9 • C lower air temperature and 2.8-4.0 kPa lower VPD at a 1 m height above the ground surface during the daytime and correspondingly 0.5-0.6 • C and 1.1-2.2 kPa during the nighttime [16].…”

Effects of shading and micro‐spray of canopy on photosynthetic characteristics, quality and yield of drip‐irrigated grapes*

“…Despite the positive impact of shading on crop production, excessive shading will decrease the photosynthesis of crops when the light intensity is lower than the light saturation point (Girona et al, 2012). Micro-spray can effectively reduce the temperature of the crop canopy, reduce the leaf-to-air water vapour pressure difference, improve the local climate of the farmland and enhance photosynthesis (Mahan et al, 1995;Jiang et al, 2020;Zheng et al, 2020). However, micro-spray can only change the surrounding air temperature and humidity of crops and fails to protect against the effect of light stress on crop photosynthesis.…”