Description

Quantifying the forage mass harvested per paddock is essential for informing late-season management decisions on grazing livestock farms. This information can be used to calculate winter feed budgets and thus support decisions such as area of land to defer for autumn grazing, and head of stock to sell before winter housing. However, there are practical limitations associated with existing measurement methods, which can influence the accuracy of forage biomass estimates. The purpose of the current study was therefore to compare biomass estimation from two alternative precision farming methods — near infrared spectroscopy (NIRS) integrated within-spout of a self-propelled forage harvester, against a rising plate meter (RPM). Data were collected from the North Wyke Farm Platform (NWFP) in South- West England. RPM readings were taken within seven days preceding harvest, and Harvester measurements taken at the point of harvest. Data from two paddocks were collected during 2021 (figure 2, points a and b) and two from 2020 (points c and d). Three of the sampled paddocks (a, c and d) contained permanent pasture and one (b) contained reseeded white clover and perennial ryegrass. Paddocks c and d in figure 2 suggest a good correspondence between methods, demonstrated by proximity to the 1:1 line which passes through the origin. However, points a and b lie parallel to the 1:1 line, suggesting a systematic underestimation from the RPM. This underestimation could be linked to the tendency of grass to lodge at high yields, or due to an unquantified factor linked to the year of harvest, such as weather conditions which are known to indirectly influence RPM readings. With suitable calibration and consideration of practical limitations, forager mounted NIRS technology can provide valuable farm management data quickly, and at a relatively low cost compared to manual methods of biomass estimation.

DOI

https://doi.org/10.13023/jssa-t579

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Comparing Forage Biomass Estimation Between Forager-Mounted Near Infrared Spectroscopy (NIRS) and Rising Plate-Meter (RPM) Techniques

Quantifying the forage mass harvested per paddock is essential for informing late-season management decisions on grazing livestock farms. This information can be used to calculate winter feed budgets and thus support decisions such as area of land to defer for autumn grazing, and head of stock to sell before winter housing. However, there are practical limitations associated with existing measurement methods, which can influence the accuracy of forage biomass estimates. The purpose of the current study was therefore to compare biomass estimation from two alternative precision farming methods — near infrared spectroscopy (NIRS) integrated within-spout of a self-propelled forage harvester, against a rising plate meter (RPM). Data were collected from the North Wyke Farm Platform (NWFP) in South- West England. RPM readings were taken within seven days preceding harvest, and Harvester measurements taken at the point of harvest. Data from two paddocks were collected during 2021 (figure 2, points a and b) and two from 2020 (points c and d). Three of the sampled paddocks (a, c and d) contained permanent pasture and one (b) contained reseeded white clover and perennial ryegrass. Paddocks c and d in figure 2 suggest a good correspondence between methods, demonstrated by proximity to the 1:1 line which passes through the origin. However, points a and b lie parallel to the 1:1 line, suggesting a systematic underestimation from the RPM. This underestimation could be linked to the tendency of grass to lodge at high yields, or due to an unquantified factor linked to the year of harvest, such as weather conditions which are known to indirectly influence RPM readings. With suitable calibration and consideration of practical limitations, forager mounted NIRS technology can provide valuable farm management data quickly, and at a relatively low cost compared to manual methods of biomass estimation.