Nutrient Management – Now and in the Future Richard Ferguson Tim Shaver University of Nebraska

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

Yield Mapping Combine

Grain Yield Monitor Components Moisture Sensor Grain Flow Sensor GPS Antenna Yield Monitor Display with a GPS Receiver Header Position Sensor Travel Speed Sensor Clean Grain Elevator Speed Sensor

Veris 3100 Soil EC a Measurement

Veris MSP: Soil pH and EC a

Crop Canopy Sensors Crop Circle ACS band Crop Circle ACS band Ultrasonic height sensors Canopy temperature sensor CropScan 2 band (laser)

Holland Scientific, Lincoln, NE. Distribution agreement with Ag Leader (OptRx system) 2 foot sensing footprint Crop Circle

Field Variability Natural color aerial photoSoil series Grain yield Soil apparent electrical conductivity False color infrared image Directed soil sample – Bray-1 P Active sensor canopy reflectance

Apparent soil deep electrical conductivity overlaid on elevation Grain yield overlaid on elevation

Current and Emerging Agricultural Technologies

Autosteer

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 Field shapes used in University of Kentucky study.

Implement Steering Options

High Clearance Sprayers In-season pesticide and fertilizer application

Linear Move and Center Pivot Irrigation Systems GPS Guidance and Variable Rate Irrigation

Variable Rate Irrigation

Optical Mapping of Soil Organic Matter

Soil Organic Matter (%) South Central Agricultural Laboratory November 2010

Soil Sensor Research On-the-go measurement of mechanical resistance, soil moisture, and soil reflectance in visible and near-infrared bands.

Hyperspectral Mapping of Soil Profile Reflectance in 384 wavebands (4 shown)

John Deere Water Management

Automated Monitoring and Telemetry Systems Total Profile Water Allowable Depletion Full Profile Profile Water Content 20” 36” 12” 4” 8” Date Water Content

Wireless Soil Water Monitoring Network

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

Crop CamOktoCopter UAVs for Aerial Imagery

OktoCopter Flight Austria

Robotics in Agriculture

Questions?