A Simple Disc Meter for Measurement of Pasture Height and Forage Bulk

Sharrow, Steven H.

doi:10.2307/3898833

Cited by 36 publications

(27 citation statements)

References 13 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These paddocks were an established bermudagrass and fescue mix and clover. Measurements were taken in accordance with the method of Sharrow (1984) for forage height, and the forage samples were a composite from 5 locations within each paddock. Forage samples were collected twice in each season; the average nutrient composition is shown in Table 1.…”

Section: Materialsand Methodsmentioning

confidence: 99%

Comparison of fatty acid, cholesterol, and vitamin A and E composition in eggs from hens housed in conventional cage and range production facilities

Anderson

2011

Poultry Science

View full text Add to dashboard Cite

The public perceives that the nutritional quality of eggs produced as free range is superior to that of eggs produced in cages. Therefore, this study compared the nutrient content of free-range vs. cage-produced shell eggs by examining the effects of the laboratory, production environment, and hen age. A flock of 500 Hy-Line Brown layers were hatched simultaneously and received the same care (i.e., vaccination, lighting, and feeding regimen), with the only difference being access to the range. The nutrient content of the eggs was analyzed for cholesterol, n-3 fatty acids, saturated fat, monounsaturated fat, polyunsaturated fat, β-carotene, vitamin A, and vitamin E. The same egg pool was divided and sent to 4 different laboratories for analysis. The laboratory was found to have a significant effect on the content of all nutrients in the analysis except for cholesterol. Total fat content in the samples varied (P < 0.001) from a high of 8.88% to a low of 6.76% in laboratories D and C, respectively. Eggs from the range production environment had more total fat (P < 0.05), monounsaturated fat (P < 0.05), and polyunsaturated fat (P < 0.001) than eggs produced by caged hens. Levels of n-3 fatty acids were also higher (P < 0.05), at 0.17% in range eggs vs. 0.14% in cage eggs. The range environment had no effect on cholesterol (163.42 and 165.38 mg/50 g in eggs from caged and range hens, respectively). Vitamin A and E levels were not affected by the husbandry to which the hens were exposed but were lowest at 62 wk of age. The age of the hens did not influence the fat levels in the egg, but cholesterol levels were highest (P < 0.001) at 62 wk of age (172.54 mg/50 g). Although range production did not influence the cholesterol level in the egg, there was an increase in fat levels in eggs produced on the range.

show abstract

Section: Materialsand Methodsmentioning

confidence: 99%

Comparison of fatty acid, cholesterol, and vitamin A and E composition in eggs from hens housed in conventional cage and range production facilities

Anderson

2011

Poultry Science

View full text Add to dashboard Cite

show abstract

“…The rising plate meter is constructed of a 40 cm diameter wide aluminium disc, which has a hole in the centre where a meter stick is passing. Plant height is determined by lowering the disc along the meter stick until the canopy surface is in contact with the disc and can be read directly off the meter stick (Sharrow, 1984). Four measurements were taken in each determined plot within the buffer zone by placing the plate gently on the grass sward until the plate was supported.…”

Section: Compressed Sward Height (Csh-ph)mentioning

confidence: 99%

“…Nowadays grassland parameters can easily be explored with modern sensor techniques, whilst field sampling and laboratory analysis can serve for calibration of the sensors and its generated data. Besides physical measurement methods providing ground truth data by using a Rising Plate Meter (RPM) or Pasture Meter, spectral measurement methods were established (Sharrow, 1984). Spectral sensors, which are installed on quads (Lawrence et al, 2007), ground based platforms (Hoffmeister et al, 2013;Tilly et al, 2014) or UAVs Bareth et al, 2015), can deliver e.g.…”

Section: Introductionmentioning

confidence: 99%

Multi-Temporal Crop Surface Models Combined With the RGB Vegetation Index From Uav-Based Images for Forage Monitoring in Grassland

Possoch¹,

Bieker²,

Hoffmeister³

et al. 2016

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

View full text Add to dashboard Cite

Commission I, ICWG I/VbKEY WORDS: Precision Agriculture, Grassland, UAV, Crop Surface Model, Structure from Motion, RGBVI ABSTRACT:Remote sensing of crop biomass is important in regard to precision agriculture, which aims to improve nutrient use efficiency and to develop better stress and disease management. In this study, multi-temporal crop surface models (CSMs) were generated from UAVbased dense imaging in order to derive plant height distribution and to determine forage mass. The low-cost UAV-based RGB imaging was carried out in a grassland experiment at the University of Bonn, Germany, in summer 2015. The test site comprised three consecutive growths including six different nitrogen fertilizer levels and three replicates, in sum 324 plots with a size of 1.5×1.5 m. Each growth consisted of six harvesting dates. RGB-images and biomass samples were taken at twelve dates nearly biweekly within two growths between June and September 2015. Images were taken with a DJI Phantom 2 in combination of a 2D Zenmuse gimbal and a GoPro Hero 3 (black edition). Overlapping images were captured in 13 to 16 m and overview images in approximately 60 m height at 2 frames per second. The RGB vegetation index (RGBVI) was calculated as the normalized difference of the squared green reflectance and the product of blue and red reflectance from the non-calibrated images. The post processing was done with Agisoft PhotoScan Professional (SfM-based) and Esri ArcGIS. 14 ground control points (GCPs) were located in the field, distinguished by 30 cm × 30 cm markers and measured with a RTK-GPS (HiPer Pro Topcon) with 0.01 m horizontal and vertical precision. The errors of the spatial resolution in x-, y-, z-direction were in a scale of 3-4 cm. From each survey, also one distortion corrected image was georeferenced by the same GCPs and used for the RGBVI calculation. The results have been used to analyse and evaluate the relationship between estimated plant height derived with this low-cost UAV-system and forage mass. Results indicate that the plant height seems to be a suitable indicator for forage mass. There is a robust correlation of crop height related with dry matter (R² = 0.6). The RGBVI seems not to be a suitable indicator for forage mass in grassland, although the results provided a medium correlation by combining plant height and RGBVI to dry matter (R² = 0.5).

show abstract

“…Systematic manual plant sampling has been used to analyse spatial distribution of dry matter yield and plant nutrient concentration and to predict its variability on grassland (Bailey et al 2001). This method requires great effort and expense to collect enough samples to accurately represent a pasture (Sharrow 1984;Hanna et al 1999;Ganguli et al 2000). Similar problems occur during the evaluation of large-size pasture yields, which require a high number of destructive samples to obtain sufficient accuracy of the estimate (Franca et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Calibration of a capacitance probe for measurement and mapping of dry matter yield in Mediterranean pastures

et al. 2011

View full text Add to dashboard Cite

The main objective of this study was to calibrate a commercial capacitance probe for measuring pasture dry matter yields under Mediterranean conditions. The standard method of assessing pasture biomass is based on cutting all the forage within a specified area and requires great effort and expense to collect enough samples to accurately represent a pasture. The field tests were carried out in 2007, 2008 and 2009 on different dates (phenological stages), and on five dairy farms, representing typical pastures in the region (grasses; legumes; and bio-diverse flora, mixture of grasses, legumes and others species). The linear regression techniques used in 2007 to relate the weight of the herbage (direct measurements) to the meter reading of capacitance (indirect measurements) led to high regression coefficients in grasses (R 2 = 0.90; P \ 0.01) and heterogeneous botanical composition (R 2 = 0.87; P \ 0.001) and moderate regression coefficient in legumes species (R 2 = 0.48; P \ 0.05). The validation of the calibration equations in 2008 and 2009 in two sites showed RSME values of 130 kg ha -1 in heterogeneous botanical composition and 456 kg ha -1 in legumes. The results indicated that the capacitance probe together with a GPS receiver might support site-specific management of pastures which would be useful in large areas.

show abstract

A Simple Disc Meter for Measurement of Pasture Height and Forage Bulk

Cited by 36 publications

References 13 publications

Comparison of fatty acid, cholesterol, and vitamin A and E composition in eggs from hens housed in conventional cage and range production facilities

Comparison of fatty acid, cholesterol, and vitamin A and E composition in eggs from hens housed in conventional cage and range production facilities

Multi-Temporal Crop Surface Models Combined With the RGB Vegetation Index From Uav-Based Images for Forage Monitoring in Grassland

Calibration of a capacitance probe for measurement and mapping of dry matter yield in Mediterranean pastures

Contact Info

Product

Resources

About