|Sudduth, Kenneth - Ken|
Submitted to: Dahlia Greidinger International Symposium
Publication Type: Proceedings
Publication Acceptance Date: 6/13/2013
Publication Date: 7/23/2013
Citation: Sudduth, K.A., Kim, H. 2014. Sensor-based precision fertilization for field crops. In: Proc. 2013 Dahlia Greidinger Memorial Symposium: Advanced Methods for Investigating Nutrient Dynamics in Soil and Ecosystems, p.255-282. March 4-7, 2013, Haifa, Israel. Interpretive Summary:
Technical Abstract: From the development of the first viable variable-rate fertilizer systems in the upper Midwest USA, precision agriculture is now approaching three decades old. Early precision fertilization practice relied on laboratory analysis of soil samples collected on a spatial pattern to define the nutrient-supplying capacity of the soil, which was then used in map-based control of variable-rate applicators. This practice is still common today, but issues of cost and practicality limit the intensity of sample collection and therefore the accuracy of the resulting precision application. A mobile soil sensing system that could be linked to a variable-rate applicator and guide fertilizer application in real time could overcome these issues. Research to develop proximal sensors for soil variables important in precision fertilization decisions began almost three decades ago and efforts to develop sensors for soil variables such as pH, plant-available phosphorus and potassium, and soil nitrate have continued to the current day. Most soil nutrient sensors developed to date have been based on either diffuse reflectance spectroscopy or electrochemical methods. While both of these approaches have advantages, they also have drawbacks which have precluded the development of a commercially viable system. An understanding of the different sensing approaches and their associated issues is an important step toward an improved system. To that end, this paper reviews the history of proximal soil nutrient sensing and describes the current state of the technology, with a focus on describing different sensor designs and applications. Future directions and considerations for soil nutrient sensing are also discussed.