Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/10/2002
Publication Date: 11/11/2002
Citation: Reddy, K.J., Zhao, D., Kakani, G., Read, J.J. 2002. Corn growth and leaf hyperspectral reflectance properties as affected by nitrogen deficiency [abstract]. Agronomy Abstracts. CD-ROM. Interpretive Summary: None required.
Technical Abstract: Experiments were conducted in ten sunlit, temperature- and humidity- controlled growth chambers in 2001 growing season to determine the effects of nitrogen (N) nutrition on corn (Zea mays L. cv 33A14) growth and leaf hyperspectral reflectance properties. We decreased N supply in the irrigation water at different days after plant emergence (DAE) to simulate low fertility conditions; otherwise, environmental conditions were favorable for plant growth. The four N treatments were 1) half-strength Hoagland's nutrient solution throughout the experiment (control); 2) 20% of the control N starting 15 days after emergence, DAE (20% N); 3) N withheld starting 15 DAE (0% N); and 4) N withheld from the nutrient solution starting 23 DAE (0% NL). Under these treatments, the concentration of N in fully expanded uppermost leaves ranged between 1.1% and 4.8% across all sampling dates. Nitrogen deficiency significantly decreased plant growth rate and leaf photosynthesis except for the 0% NL treatment. At final harvest, the plant height, leaf area and shoot biomass were only about 64-66% of the control for 20% N treatment, and 46-56% of the control for 0% N treatment. Nitrogen deficiency treatments of 20% N and 0% N could be discriminated by using leaf spectral reflectance in the visible and near infrared ranges (400-800 nm) at 7 days after treatments were commenced. This paper also will discuss relationships obtained between changes in leaf reflectance and the concentration of N, chlorophyll or total phenolics in mature corn leaves.