A Retrofit Variable-Rate Control System for Pressurized Slurry Tankers

Abstract

ffluent management has become increasingly important among livestock farming activities because of: i) the need to valorize a sub-product with a high fertilizing potential, ii) the high costs associated with spreading operations, and iii) the environmental impacts that could result from inadequate effluent management at the farm level. Due to this issue, the European Commission issued several Directives aimed at protecting the environment while ensuring that farmers could achieve proper production levels (Ruiz-Ramos et al., 2011). In particular, Directive 91/676/EC is currently the main regulation aimed at protecting water from nitrate accumulation due to farming operations. Due to this directive, nitrate vulnerable zones (NVZs) have been set with strict regulations regarding the timing and rates of nitrogen application in these zones. In the NVZs, a specific threshold limits the application rate to 170 kg ha -1 y -1 for nitrogen. However, this threshold is normally 340 kg ha From a technology perspective, strict compliance with these limits can be achieved using control systems that use "variable rate technology" (VRT) for spreading fertilizer. These systems are generally classified into four groups that correspond to the following increasing automation levels adapted from Funk and Robert, (2003).• Automation level 0: This system uses a constant-flow rate distribution and requires devices to deliver a predefined rate of effluent regardless of the operating conditions. The authors are Aldo Calcante, Assistant Professor, Roberto Oberti, Assistant Professor, Università degli Studi di Milano, Department of Agricultural and Environmental Sciences, Milan, Italy; Massimo Brambilla, Researcher, and Carlo Bisaglia, Senior Researcher, Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria

Achieving the nutrient reduction objective of the Farm to Fork Strategy. An assessment of CAP subsidies for precision fertilization and sustainable agricultural practices in Germany

“…Then, forward speed of a tractor or the valve position is adjusted according to the fertilizer amount specified by the prescription map. This approach works for mineral fertilizers as well as farm manure and slurry (Grisso et al, 2011;Calcante et al, 2015). Fully automated technologies do not require prescription maps but use real-time sensors to collect and process data in situ (Yang et al, 2016, p. 180-186;Balafoutis et al, 2017, p. 7).…”