Thermal imaging for assessment of maize water stress and yield prediction under drought conditions

Abstract

Maize production in Thailand is increasingly suffering from drought periods along the cropping season. This creates the need for rapid and accurate methods to detect crop water stress to prevent yield loss. The study was, therefore, conducted to improve the efficacy of thermal imaging for assessing maize water stress and yield prediction. The experiment was carried out under controlled and field conditions in Phitsanulok, Thailand. Five treatments were applied, including (T1) fully irrigated treatment with 100% of crop water requirement (CWR) as control; (T2) early stress with 50% of CWR from 20 days after sowing (DAS) until anthesis and subsequent rewatering; (T3) sustained deficit at 50% of CWR from 20 DAS until harvest; (T4) late stress with 100% of CWR until anthesis and 50% of CWR after anthesis until harvest; (T5) late stress with 100% of CWR until anthesis and no irrigation after anthesis. Canopy temperature (FLIR), crop growth and soil moisture were measured at 5‐day‐intervals. Under controlled conditions, early water stress significantly reduced maize growth and yield. Water deficit after anthesis had no significant effect. A new combination of wet/dry sponge type reference surfaces was used for the determination of the Crop Water Stress Index (CWSI). There was a strong relationship between CWSI and stomatal conductance (R² = 0.90), with a CWSI of 0.35 being correlated to a 64%‐yield loss. Assessing CWSI at 55 DAS, that is, at tasseling, under greenhouse conditions corresponded best to the final maize yield. This linear regression model validated well in both maize lowland (R² = 0.94) and maize upland fields (R² = 0.97) under the prevailing variety, soil and climate conditions. The results demonstrate that, using improved standardized references and data acquisition protocols, thermal imaging CWSI monitoring according to critical phenological stages enables yield prediction under drought stress.

Deficit irrigation maintains maize yield through improved soil water extraction and stable canopy radiation interception

“…Canopy temperature provides an insight into the water status of the canopy and is related to plant growth and health. The differences in the canopy temperature in the same environment have been widely used as a useful indicator of water stress during the crop growing season (Pradawet et al, 2022; Sharma & Ritchie, 2015). In the current study, canopy temperature differences between the two water regimes from August 16 (92 days after planting) to September 23 (123 days after planting) in 2016 are shown in Figure 4.…”

Phenotyping wild potatoes (Solanum Sect. Petota) for photosynthesis associated traits under heat stress.

“…BGB003 of S. commersonii, BGB093 of S. tuberosum 2x, and ve accessions of S. chacoense (BGB086, BGB101, BGB109, BGB467, BGB472) fall within the above-mentioned ratios under heat stress. A decrease in this ratio is thought to be a good indicator of photoinhibition (Pradawet et al, 2023). As shown by 60% of assessed germplasm, whereas BGB107 and BGB113 were the most susceptible to heat stress genotypes due to photoinhibition.…”

Response of “Lollo Bionda” lettuce to drip and porous pipe irrigation

“…Physiologically, the faster crop development can be explained by the stage of the rapid crop development which precedes the period before anthesis (Pradawet et al 2022). For lettuce, this stage determines the yield as the crop must be harvested before physiological maturity.…”