Schellberg and Lock (2009) conducted a study that designed software and hardware systems to control the application of slurry to grasslands and agricultural crops. They theorized that if the application process of the slurry, utilized as a crop fertilizer, could be controlled to a high degree of accuracy based on a fertilizer application map, specific to the field of cultivation, large N losses to the environment and over-fertilization of the crops would be avoided. This study did not evaluate the effectiveness of their site-specific slurry application techniques in the form of crop yield or spatial distribution of N. Instead, the effectiveness of the software and hardware systems to work together and produce the accurate application levels as determined in the application map were of concern in the study. — <!–[if supportFields]> CONTACT _Con-3EF86BDE1 \c \s \l <![endif]–>Maria Harwood<!–[if supportFields]><![endif]–>
Schellberg, J., Lock, R., 2009. A Site-specific Slurry Application Technique on Grassland and on Arable Crops. Bioresource Technology 100, 280–286.
Schellberg and Lock used cattle slurry in their two field application experiments on a grassland used for forage and a field of corn. The key issues in applying this technique lay in the ability to determine the local nutrient demand of the plants and the need for an advanced on-field monitoring system tracking the release of the slurry. The authors tackled the latter problem by creating a software and hardware system to actively control the flow rate of the slurry during application. The various parameters that they measured include the dry matter yield, the dry matter content in the harvested material, the plant N content, the estimated N extraction by plants, the mineralized N in the fields, and the calculated N fertilizer. These data were used as input parameters to their software system to ultimately determine the correct amount of N fertilizer, or slurry, to be applied to the varying locations within the field.
This article pointed to the accuracy of the application map as the key to the site-specific application of slurry, although they noted that the size of the grid cells within the field for slurry application have to be significantly small to produce accurate results. There also was a time lag noted within the equipment as it attempted to adjust as it entered a geographic region of the field that required a varying amount of slurry.