Origins of Soil Spatial Variability Natural: Soil = f (c, o, r, p, t) H. Jenny (1941) c: climate o: organisms (plants, microbes, insects, animals) r: relief (topography) p: parent material t: time Management induced (humans): Land use (cropping systems, field boundaries) Old roads, farmsteads, etc. Earth movement (land leveling, terraces) Tillage & traffic Planting patterns (e.g., in row crops) Fertilizer application, other amendments (lime, manure) Irrigation & salinity Crop nutrient removal (yield and crop residue management)
Goal: To manage spatial and temporal availability of inputs, including fertilizer, for optimal crop production and efficiency of resources. This requires an understanding of the variability of soil resources, and the ability to apply fertilizer at the right time and rate.
Measurement of Spatial Variability in Fields Experience County soil survey maps Photographs & multispectral imagery Aerial Satellite Yield maps Topography/digital elevation models (DEM) Apparent soil electrical conductivity (EC a ) Grid or directed soil samples Soil sensors Electrochemical Electrical & electromagnetic Mechanical Optical Crop canopy sensors Optical Acoustic Thermal
Swath Control Investments for planter clutches and boom section plumbing for sprayers will vary widely, with costs increasing for more precise control. Investments for planter clutches and boom section plumbing for sprayers will vary widely, with costs increasing for more precise control. Savings and gains in efficiency will increase as field shapes becomes more irregular. Savings and gains in efficiency will increase as field shapes becomes more irregular.
Swath Control Standard planter or sprayer approachPlanter or sprayer with swath control on every row or nozzle
Swath Control – Economic Impact A University of Kentucky study found substantial input cost savings from swath control adoption on irregularly shaped fields. At medium fertilizer rates, moving from lightbar direction to lightbar direction with swath control resulted in savings of $25 to $33.48/acre. Presented at the 9 th International Conference on Precision Agriculture, Denver, CO, July 2008. Field shapes used in University of Kentucky study.
Derrel Martin, Biological Systems Engineering Remote Control of Irrigation Systems Pictures Courtesy of Valmont Industries
Three-axis attitude sensor GPS antenna Radio modem and antenna Air tanks and pistons for retractable landing gear Gyroscope Video transmitter and antenna Remote-Sensing Unmanned Aerial Vehicles (UAVs) To monitor crop stress and onset of insect or disease infestation