CALIBRATING CHLOROPHYLL METER (SPAD-502) READING BY SPECIFIC LEAF AREA FOR ESTIMATING LEAF NITROGEN CONCENTRATION IN SWEET SORGHUM

Estimating Corn Leaf Chlorophyll Concentration from Leaf and Canopy Reflectance

Farmers must balance the competing goals of supplying contributions of background reflectance, while spectral vegetation indices that combined reflectances of near-infrared adequate N for their crops while minimizing N losses to the environment. To characterize the spatial variability of N and other visible bands (MCARI and NIR/Green) were responsive to both leaf chlorophyll concentrations and ...

Optimal Leaf Positions for SPAD Meter Measurement in Rice

The Soil Plant Analysis Development (SPAD) chlorophyll meter is one of the most commonly used diagnostic tools to measure crop nitrogen status. However, the measurement method of the meter could significantly affect the accuracy of the final estimation. Thus, this research was undertaken to develop a new methodology to optimize SPAD meter measurements in rice (Oryza sativa L.). A flatbed color ...

Association of root, specific leaf area and SPAD chlorophyll meter reading to water use efficiency of peanut under different available soil water

Drought is the major abiotic constraint affecting peanut productivity and quality worldwide. There is a pressing need to improve the water use efficiency (WUE) of rain-fed peanut production. Breeding varieties with higher water use efficiency is seen as providing part of the solution. The objectives of this work were to (i) evaluate genetic variation in WUE, harvest index, root dry weight, spec...

Rice Leaf Lateral Asymmetry in the Relationship between SPAD and Area-Based Nitrogen Concentration

Rice leaves display lateral asymmetry around the midrib, and the narrow side exhibits higher leaf area-based nitrogen concentration (Na) and soil plant analysis development (SPAD) values than the wider side. However, the difference in the relationship between the SPAD of each side and Na of the corresponding lateral half, and the optimal position along the leaf blade for SPAD measurements are n...

Leaf Photosynthetic Capacity, Chlorophyll Content, and Specific Leaf Nitrogen Relationships in Sunflower Crops Prior to Anthesis