Precision Agriculture

, Volume 15, Issue 3, pp 304–320 | Cite as

A model to analyze as-applied reports from variable rate applications

  • André Freitas Colaço
  • Hugo José de Andrade Rosa
  • José Paulo MolinEmail author


During variable rate operations, controller systems report information (as-applied files) about desired rates and real applied rates on georeferenced points along the machine tracks. These reports are useful for operation quality control but they have not been widely used to their potential. The goal of this study was to create a model to help analyzing as-applied files based on quantifying and locating off-rate errors and their probable related sources. The model calculates off-rate error at every point and classifies them as less than target rate, acceptable or over the target rate. Possible error sources are classified regarding three aspects: vehicle path position (inward, middle or outward), high rate change (step up or down) and vehicle acceleration or deceleration. A pulled type applicator (application 1) and a self-propelled applicator (application 2) were analyzed. An average of 30.6 % of the recorded points was considered application errors (10 % off the target rate). 70.5 % of them occurred on high rate change points on application 1 and 69.7 % on acceleration/deceleration points on application 2. The self-propelled applicator performed better during high transition rate than the pulled type which performed poorly when transition rate exceeded 10 %. The model determined the major and minor factors related to application error. It provided means to assess equipment limitations and its impact over the quality of application. The trials demonstrated its flexibility and how it can improve the use of as-applied files.


Variable rate As-applied files Off-rate error Application error sources Model 


  1. Chan, C. W., Schueller, J. K., Miller, W. M., Whitney, J. D., & Cornell, J. A. (2004). Error sources affecting variable rate application of nitrogen fertilizer. Precision Agriculture, 5, 601–616.CrossRefGoogle Scholar
  2. Cugati, S. A., Miller, W. M., Schueller, J. K., Schumann, A. W., Buchanon, S. M., & Hostler, H. K. (2007). Benchmarking the dynamic performance of two commercial variable-rate controllers and components. Transactions of the ASABE, 50(3), 795–802.CrossRefGoogle Scholar
  3. Fulton, J. P., Shearer, S. A., Higgins, S. F., Darr, M. J., & Stombaugh, T. S. (2005). Rate response assessment from various granular vrt applicators. Transactions of the ASABE, 48(6), 2095–2103.CrossRefGoogle Scholar
  4. Fulton, J. P., Shearer, S. A., Higgins, S. F., & McDonald, T. P. (2013). A method to generate and use as-applied surfaces to evaluate variable-rate fertilizer applications. Precision Agriculture, 14, 184–200.CrossRefGoogle Scholar
  5. Fulton, J. P., Shearer, S. A., Stombaugh, T. S., Anderson, M. E., Burks, T. F., & Higgins, S. F. (2003). Simulation of fixed- and variable-rate application of granular materials. Transactions of the ASABE, 46(5), 1311–1321.Google Scholar
  6. Goense, D. (1997). The accuracy of farm machinery for precision agriculture: a case for fertilizer application. Netherlands Journal of Agricultural Science, 45, 201–217.Google Scholar
  7. Lawrence, H. G., & Yule, I. J. (2007). Modeling of fertilizer distribution using measured machine parameters. Transactions of the ASABE, 50(4), 1141–1147.CrossRefGoogle Scholar
  8. Schumann, A. W., Miller, W. M., Zaman, Q. U., Hostler, K. H., Buchanon, S., & Cugati, S. (2006). Variable rate granular fertilization of citrus groves: spreader performance with single-tree prescription zones. Applied Engineering in Agriculture, 22(1), 19–24.CrossRefGoogle Scholar
  9. Tumbo, S., Salyani, M., Miller, W., Sweeb, R., & Buchanon, S. (2007). Evaluation of a variable rate controller for aldicarb application around buffer zones in citrus groves. Computers and Electronics in Agriculture, 56(2), 147–160.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  • André Freitas Colaço
    • 1
  • Hugo José de Andrade Rosa
    • 1
  • José Paulo Molin
    • 1
    Email author
  1. 1.Biosystems Engineering Department, “Luiz de Queiroz” College of AgricultureUniversity of São PauloPiracicabaBrazil

Personalised recommendations