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ARS Home » Plains Area » El Reno, Oklahoma » Oklahoma and Central Plains Agricultural Research Center » Livestock, Forage and Pasture Management Research Unit » Research » Publications at this Location » Publication #375024
Research Project: Integrated Agroecosystem Research to Enhance Forage and Food Production in the Southern Great Plains

Location: Livestock, Forage and Pasture Management Research Unit

Title: Canopy temperature depression and normalized difference vegetation index as indicators of drought resistance and nitrogen recommendation in hybrid maize genotypes

Author
item NEUPANE, BIPIN - Ministry Of Agriculture And Rural Equipment (MAER)
item POUDEL, ANKUR - Ministry Of Agriculture And Rural Equipment (MAER)
item Wagle, Pradeep

Submitted to: Azarian Journal of Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2020
Publication Date: 10/9/2020
Citation: Neupane, B., Poudel, A., Wagle, P. 2020. Canopy temperature depression and normalized difference vegetation index as indicators of drought resistance and nitrogen recommendation in hybrid maize genotypes. Azarian Journal of Agriculture. 7(3):69-75. https://dx.doi.org/10.29252/azarinj.031.
DOI: https://doi.org/10.29252/azarinj.031

Interpretive Summary: Normalized difference vegetation index (NDVI, an indication of vegetation coverage and canopy greenness) and canopy temperature depression (CTD, difference between air temperature and canopy temperature) were measured periodically (15, 30, 45, and 60 days after seeding, DAS) in 14 maize genotypes during a growing season. The NDVI and CTD were used as indicators of drought resistance and N recommendation in hybrid maize genotypes. Both NDVI and CTD at all measured DAS showed significant positive relationships with grain yield. However, correlations coefficients were the highest at 45 DAS. The NDVI-based nitrogen (N) calculator showed N requirement for the yield potential under the farmers’ nutrient management levels, regardless of genotypes, was nearly half of the recommended N dosages. To obtain the expected grain yields and gross returns, results indicate that top dressing of ~54 kg N/ha is required at 45 DAS. Nitrogen requirements decreased as crop growth progressed towards the reproductive stage. Results indicated that 45 DAS was an appropriate time for top dressing of N, and application of N at a later stage of crop growth had a smaller advantage.

Technical Abstract: Improving maize production is one of the most effective strategies for food security. Differences in normalized difference vegetation index (NDVI), canopy temperature depression (CTD), and grain yield were evaluated for 14 hybrid maize genotypes in randomized complete block design with three replications at Sundarbazar, Lamjung, Nepal. During a growing season (May to September 2019), NDVI was measured using a GreenseekerTM handheld sensor to predict in-season yield and nitrogen (N) recommendations. The CTD was measured using a Fluke infrared thermometer to estimate yield and rank heat resistant genotypes. Both NDVI and CTD showed significant positive relationships with grain yield. For NDVI, correlation coefficients were 0.81, 0.72, 0.87, and 0.70 at 15, 30, 45, and 60 days after seeding (DAS), respectively. For CTD, correlation coefficients were 0.64, 0.67, 0.76, and 0.76 at 15, 30, 45, and 60 DAS, respectively. Nitrogen requirement from NDVI-based N calculator for the yield potential under farmers’ nutrient management levels, regardless of genotypes, was nearly half of the recommended N dosages. The genotypes with negative CTD values (RML-11-2/ RML-18, RL-35-1/RL-105, and RL-24-0/RL-111) were particularly prone to heat stress, while all other genotypes were heat stress resistant. To obtain the expected grain yields, results indicate that top dressing of ~54 kg N/ha is required at 45 DAS. Nitrogen requirements decreased as crop growth progressed towards the reproductive stage. Results indicated that 45 DAS was an appropriate time for top dressing of N, and application of N at a later stage of crop growth had a smaller advantage.