Reflectance of litter accumulation levels at five wavelengths within the 0.5- to 2.5 micron waveband

Reflectance was measured for 1-m2 range grass plots with two canopy treatments (standing and clipped) and four levels of litter accumulation and for grain sorghum with two canopy treatments. Reflectance was significantly higher at the 0.65- to 1.65-, and 2.20-micrometer. Wavelengths for both grass and grain sorghum canopies when the canopies were clipped and the resulting litter was removed. The natural accumulation of litter under the grass canopy did not significantly affect reflectance. The 1.65- and 2.20-micrometer wavelength reflectances of the live grass and the intact litter were 21.8% and 16.2%, respectively, and those of grain sorghum were 21.8% and 16.5%, respectively

Relationship of film optical density to yield indicators

Relationship between preharvest yield indicators and film densities of aerial infrared film in microexperiment

Vegetation density as deduced from ERTS-1 MSS response

Reflectance from vegetation increases with increasing vegetation density in the 0.75- to 1.35 micron wavelength interval. Therefore, ERTS-1 bands 6 (0.7 to 0.8 micron) and 7 (0.8 to 1.1 micron) contain information that should relate to the probable yield of crops and the animal carrying capacity of rangeland. The results of an experiment designed specifically to test the relations among leaf area index (LAI), plant population, plant cover and plant height, and the ERTS-1 MSS responses for 3 corn, 10 sorghum, and 10 cotton fields are given. Plant population was as useful as LAI for characterizing the sorghum and corn fields, and plant height was as good as LAI for characterizing cotton fields. These findings generally support the utility of ERTS-1 data for explaining variability in green biomass, harvestable forage and other indicators of productivity

Reflectance of vegetation, soil, and water

The author has identified the following significant results. Iron deficient and normal grain sorghum plants were sufficiently different spectrally in ERTS-1 band 5 CCT data to detect chlorotic sorghum areas 2.8 acres (1.1 hectares) or larger in size in computer printouts of the MSS data. The ratio of band 5 to band 7 or band 7 minus band 5 relates to vegetation ground cover conditions and helps to select training samples representative of differing vegetation maturity or vigor classes and to estimate ground cover or green vegetation density in the absence of ground information. The four plant parameters; leaf area index, plant population, plant cover, and plant height explained 87 to 93% of the variability in band 6 digital counts and from 59 to 90% of the variation in bands 4 and 5. A ground area 2244 acres in size was classified on a pixel by pixel basis using simultaneously acquired aircraft support and ERTS-1 data. Overall recognition for vegetables, immature crops and mixed shrubs, and bare soil categories was 64.5% for aircraft and 59.6% for spacecraft data, respectively. Overall recognition results on a per field basis were 61.8% for aircraft and 62.8% for ERTS-1 data

Soil, water, and vegetation conditions in south Texas

The author has identified the following significant results. Software development for a computer-aided crop and soil survey system is nearing completion. Computer-aided variety classification accuracies using LANDSAT-1 MSS data for a 600 hectare citrus farm were 83% for Redblush grapefruit and 91% for oranges. These accuracies indicate that there is good potential for computer-aided inventories of grapefruit and orange citrus orchards with LANDSAT-type MSS data. Mean digital values of clouds differed statistically from those for crop, soil, and water entities, and those for cloud shadows were enough lower than sunlit crop and soil to be distinguishable. The standard errors of estimate for the calibration of computer compatible tape coordinate system (pixel and record) to earth coordinate system (longitude and latitude) for 6 LANDSAT scenes ranged from 0.72 to 1.50 pixels and from 0.58 to 1.75 records

Reflectance of vegetation, soil, and water

The author has identified the following significant results. Bands 4, 5, and 7 and 5, 6, and 7 were best for distinguishing among crop and soil categories in ERTS-1 SCENES 1182-16322 (1-21-73) and 1308-16323 (5-21-73) respectively. Chlorotic sorghum areas 2.8 acres or larger in size were identified on a computer printout of band 5 data. Reflectance of crop residues was more often different from bare soil in band 4 than in bands 5, 6, and 7. Simultaneously acquired aircraft and spacecraft MSS data indicated that spacecraft surveys are as reliable as aircraft surveys. ERTS-1 data were successfully used to estimate acreage of citrus, cotton, and sorghum as well as idle crop land

Chemical Composition of Native Range Grasses Growing on Saline Soils of the South Texas Plains

During the growing seasons of 1976 and 1977, six native range grass species and a composite of miscellaneous grasses growing on Saline Clay and Rolling Hardland range sites (both sites have saline soils) in south Texas were analyzed for percentage content of crude protein (CP), P, Ca, Mg, K, and Na. Levels of CP, P, K, and Na were generally highest after periods of adequate rainfall in late spring, summer, and early fall and lowest in late fall as the grasses went into dormancy. Levels of Ca and Mg remained relatively stable through the growing season and showed little relationship to rainfall. Grasses from the Saline Clay site had slightly higher levels of the chemical constituents than those grasses from the Rolling Hardland site.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

LANDSAT-2 Data for Inventorying Rangelands in South Texas

A 81,000-ha rangeland area in Kenedy and Willacy Counties, Texas, was used to test LANDSAT-2 MSS data from October 17 and December 10, 1975 for inventorying rangeland and various other land-use categories. Computer land-use classification percentages of land cover for each overpass were compared with photo-estimated percentages from a ground correlated 1:100,000 scale LANDSAT color composite print. We found a highly significant correlation (r = 0.977**) between the photo- and computer-estimated hectarages for the October LANDSAT-2 overpass. The correlation was not significant for the December overpass largely because about half of the most extensive rangeland category (mixed brush) was misclassified as grassland, probably because the woody species were dormant and freeze damage had weakened the herbaceous vegetation reflectance. Computer estimates of level I land-use (rangeland, wetland, agricultural land, water, and barren land) hectarage from both overpasses resembled photo-estimated hectarages, indicating the feasibility of estimating level I land-use categories in either October or December. Computer estimates of level II land-use (grasslands, mixed brush, and live oak rangelands) hectarages agreed with photo-estimated hectarages only in October, indicating that living vegetation is needed to spectrally discriminate between level II rangeland categories

Canopy Reflectance and Film Image Relations among Three South Texas Rangeland Plants

Field spectroradiometric measurements for canopy reflectances of three dominant south Texas woody plants (cenizo, honey mesquite, live oak) were used successfully to predict their color infrared film images and distinguishability: cenizo, whitish; honey mesquite, relatively light magenta; and live oak, darker magenta.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202