Mapping Crop Residue Cover Over Regional Agricultural Landscapes in Canada

Land management practices affect the long term sustainability of agricultural soils. Growing Forward, Agriculture and Agri-Food Canada’s (AAFC) agricultural policy framework, has identified promoting environmentally responsible agriculture as one of the department’s priorities. Land management information requirements have become increasingly important to a number of programs and policies supporting the Canadian agriculture sector. Earth observing satellites can assist with monitoring tillage activities but to implement an operational monitoring system for a country as large as Canada, large-swath optical satellites are required. AAFC has developed a spectral unmixing method to estimate crop residue cover, an indicator of land management practices, from the SPOT satellite. However, implementation of this method for monitoring over vast regions would be challenging given this sensor’s limited swath (60 km). AWiFS acquires data over a swath of 740 km and at a spectral resolution similar to SPOT. Thus, it is anticipated that monitoring residue cover over large regional landscapes can be accomplished with the AWiFS satellite. AWiFS image data were acquired on October 12 2010 over the Brunkild watershed (near Winnipeg, Manitoba) in the Canadian Prairies. Simultaneous ground data were collected to characterize canola, lentil and small grain residues. Spectral unmixing analysis was applied to the AWiFS data. This approach produced overall crop residue cover estimates with a root mean square error of 20.18%. Errors were lower for lentil fields (17.00%) and comparable for canola (22.19%) and small grains (21.29%).