Soil Core Analysis Network for In-Field Measurements of Nitrogen and Other Soil Properties

Fertilizer application rates that do not match crop usage pose an economic loss for farmers, and excess applications can result in environmental degradation of water and atmosphere. A significant portion of the nitrogen applied to U.S. fields is not needed, due to the availability of nitrogen from the soil. Soil nutrients, especially nitrogen, vary spatially and temporally, within the field and soil profile. In order to deal with the significant variability challenges, a large number of soil measurements must be taken on each field. Using conventional lab analysis, this is not cost-effective. In-field measurements represent an appealing alternative, yet these must be accurate and affordable. This project will develop the field-deployable test equipment required to evaluate several sensor technologies in a side-by-side comparison. Soil sensing technology used for this application will be electrical, optical, and electro-chemical. The sensors to be used in this project represent the most viable candidates from those categories, and have shown initial feasibility to meet the criteria. However, most have not been widely tested under in-field conditions, nor has a thorough side-by-side comparison been conducted. In order to perform this feasibility comparison test, equipment will be devised to collect and process the soil cores, and bring them into contact with the sensors. Results from in-field sensors will be compared with laboratory-analyzed soil tests.