ABSTRACT
Variable-rate application technologies in precision agriculture Kenneth A. Sudduth, USDA-ARS, USA; Aaron J. Franzen, South Dakota State University, USA; and Heping Zhu and Scott T. Drummond, USDA-ARS, USA
1 Introduction
2 Characteristics of VRA control systems
3 Liquid VRA systems
4 Dry VRA systems
5 Case studies
6 Current status
7 Future trends and conclusion
8 Where to look for further information
9 References
Precision agriculture (PA) can be thought of as being composed of a ‘menu’ of available management operations, with the overall PA system being different depending on what operations are selected for a particular farm or field. For example, one farmer may only practice variable-rate application (VRA) of nitrogen (N) fertilizer, while another farmer’s PA system may include VRA of all fertilizer applied, plus precision herbicide and pesticide application. Regardless, the PA approach can be viewed as cyclic in nature, involving data collection, development of management plans, implementation of those plans in the field and evaluation of the effort (Fig. 1).
