Field chlorophyll measurements for evaluation of corn nitrogen status¹

Abstract

An experiment was conducted on Norfolk sandy loam soil (Fineloamy, siliceous, thermic Typic Kandiudults) during two years to determine the feasibility of using field chlorophyll measurements for evaluation of corn (Zea mays L.) N status. Nitrogen was applied at rates of 56, 112, 168, 224, 280 and 336 kg ha -1 to establish a range of corn chlorophyll levels, tissue N concentrations, and grain yields. At the V10 and midsilk stages of growth, field chlorophyll measurements were taken with a hand-held chlorophyll meter (SPAD-502 Chlorophyll Meter, Minolta Camera Co., Ltd., Japan) 3 and tissue N was determined. A typical curvilinear grain yield response to N fertilizer was observed both years; maximum agronomic yields were obtained with 227 and 242 kg N ha 1 , respectively, in 1990 and 1991. Tissue N concentrations at V10 and midsiik were a good predictor of grain yield. Field chlorophyll measurements were highly correlated with tissue N concentrations at both growth stages during both years of the study. Field chlorophyll measurements had excellent grain yield prediction capabilities, even at V10, which shows promise for utilization of this tool for in-season N recommendations. However, further calibration of field chlorophyll measurements will be required prior to routine use for corn N recommendation purposes.

Effects of Crop Leaf Angle on LAI-Sensitive Narrow-Band Vegetation Indices Derived from Imaging Spectroscopy

“…For example, the leaf chlorophyll content (Cab) and green LAI are often closely related [41], which was also the case for the field data used in the study (Figure 4). As the application of nitrogen increases the chlorophyll content [42], the level of fertilization has an impact on the performance of LAI-sensitive VIs if these also depend on Cab. Furthermore, a similar indirect influence of Cab on the studied VIs is possible if the Cab values are dominated by between-species differences.…”

Differentiation of Life-History Traits among Palmer Amaranth Populations (Amaranthus palmeri) and Its Relation to Cropping Systems and Glyphosate Sensitivity

“…At this point, multiple traits were measured: days to flowering, plant height, and greenness measured using a SPAD 502 Plus Chlorophyll Meter (Spectrum Technologies, Lincoln, NE) on the second, third, and fourth leaves (Wood et al 1992) and averaging the results per plant. In order to assess allometric variability for leaf and canopy components, the second and third fully developed leaves were measured for petiole and leaf-blade length and for width at three equidistant sections along the leaf blade (tip, middle, and basal section).…”

Comparison of Nitrogen Fertilization Methods and Rates for Subsurface Drip Irrigated Corn in the Semi-Arid Great Plains

“…N content of plant leaves is related to chlorophyll content in plant leaves. Research showed correlations (R) between measured SPAD readings and N content in plant leaves between 0.89 and 0.91 (Wood et al, 1992;Anderson et al, 1993). Within each plot, 20 readings were taken on 20 leaves midway between the collar of the latest fully expanded leaf that had formed at the leaf/stalk junction and the tip of the leaf, and midway between the midrib and edge of the leaf.…”