Abstract

The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) recommends that farmers maintain at least 30% soil cover throughout the year to reduce farmland topsoil and nutrient losses that impact water quality.   Available crop residue level measurement methods are labourious and time consuming.   Farmers, agricultural specialists and researchers need a reliable, convenient and rapid residue measurement tool.   Today’s handheld mobile devices (tablets and smart phones) are equipped with digital cameras and global positioning systems (GPS).   This mobile technology provides an opportunity for crop residue cover assessment application (“app”) development.   This pilot project tested and calibrated this new method against existing techniques and demonstrate it to farmers with the aid of OMAFRA staff.   Eventually, all Ontario farmers interested in measuring their field crop residue levels will be able to download this mobile application.   They will also have the option to contribute their results to a common data warehouse.

Project Descriptioin

Soil erosion results in non-point source pollution of receiving waters.   Eroded sediments carry productive topsoil, nutrients and pesticides off farmland to impair streams, lakes and shoreline waters.   This remains an environmental concern, not just in the Great Lakes region, but globally.   Tillage and planting systems that leave a protective cover of plant residue on the soil surface have been shown to reduce soil losses from cropland.   They are among the least costly erosion control practices available to farmers (Dodd et al, 1989).   Crop residue cover acts as a protective shield for the soil surface.   It helps to protect the soil particles from the erosive forces of raindrop impact, rainfall and snowmelt runoff, and wind.   Through time, as these crop residues decompose, organic matter levels in the topsoil increase.   This improves soil structure and health. These surface residues slow surface water flow.   Fewer tillage passes on fields may result in less compaction.   The resulting improved soil structure leads enhanced infiltration into the soil.   Residue cover can also reduce soil evaporation losses.   This conserves soil moisture.   For these reasons, many regard soil residue management as a key climate change adaptation strategy.   It provides resiliency to cope with the anticipated more intense, yet infrequent, rains in the Summer growing season, prolonged plant moisture stress conditions and the need for increased water efficiency.

The ability of a tillage or planting system to maintain soil residue cover is currently measured by using one or more of the following methods:

• Line transect method (e.g. knotted rope)
• Meter stick method
• Photo comparison method
• Calculation method
• Photographic grid method

Each of these techniques, described more completely by Dodd et al. (1989), has various advantages and disadvantages.   A common feature of each, however, is that they tend to be labourious and time-consuming to complete properly.   For this reason, few landowners actually measure their field residue levels.   As a consequence, there is not good documentation with which to assess whether or not cropland residue levels are improving or declining through time.   As a result, the progress of agricultural land managers and the successes of policies and programs aimed at tackling soil erosion mitigation, reducing rural non-point source pollution loadings, and adapting to climate change, are not easily quantified.   This project aims to develop and test a tool that takes advantage of today’s widespread availability and adoption by the farm community of handheld devices, equipped with cameras and GPS.   It will provide for convenient and rapid crop residue cover estimation.

Reference List:   Dodd, V. A., Grace, P.M., Dickey, E.C., Shelton, D.P., Meyer, G.E. and Fairbanks, K.T. 1989. Determining crop residue cover with electronic image analysis. Biological Systems Engineering; Papers and Publications. Paper 238.

This project was supported by the following partners: