The Application of Harvester -Mounted Forage Yield Sensing Devices.

Abstract

The development and application of precision agriculture technology to forage crops offers scope for improved management practices and targeting of inputs. In particular, the ability to measure forage throughput on a harvester would form the basis for improved management decisions and the ability to exploit precision agriculture technology, including accurate application of forage additives. The aim of this project was to develop a forage throughput sensor and to use that sensor to record yield variability and to accurately control additive application. Following preliminary trials, a force sensing plate placed in a forage harvester chute was developed and assessed. A very good relationship between sensed throughput and measured throughput was achieved, with regression coefficients of between 0.88 and 0.96 recorded in a series of trials. The relationship was established on a fresh-weight basis. Calibration could present difficulties in practice. The forage throughput sensor was linked to a GPS positioning system and a modified yield monitor/recording system to facilitate the measurement of yield variability in the field. Considerable difficulties were encountered with compatibility of the various components, including the analysis software. While a forage yield map was created and illustrated the levels of yield variability within a field, the need for simultaneous on-harvester dry matter sensing was apparent. A throughput-based additive application control system was designed, developed and tested. The unit performed satisfactorily, resulting in less variation in the quantity of additive applied to harvested grass compared to conventional application systems. In conclusion, there is scope for the application of precision agriculture technology, based on forage yield sensing, on grassland farms. However, there are many differences between the adoption of this technology on grassland farms compared to arable farms. In particular, yield-sensing accuracy is unlikely to be as good, and the need for simultaneous DM sensing is critical. Forage yield sensors will be commercialised soon. There will then be a need to evaluate these systems and the application of precision agriculture technology to grassland systems.