Crop residue can help reduce erosion, maintain soil moisture, improve soil tilth and quality, reduce nutrient runoff, and provide wildlife cover. These benefits can be related to potential yield benefits and should be considered when managing residue (Table 1). Conservation tillage practices resulting in greater sustainability of cropping systems are being adopted on a wider scale compared to the traditional moldboard plowing.
Residue can be managed through harvesting steps and tillage; however, tillage may not be desirable in all fields. Depending on crop rotation, additional steps may help decompose residue or allow for residue handling during planting of the next crop.
It may be helpful or required for conservation programs to estimate the percentage of crop residue cover. In some areas, about 12 to 20 percent residue is needed to protect relatively flat fields from water erosion. Fields with long or steep slopes may require at least 50 to 60 percent residue cover.6 The USDA recommends using the line-transect method for estimating and reporting percent residue cover. This method involves simple field observations and measurements using a 50- to 100-foot long measuring tape, line, or rope that can be marked at 100 equal intervals. Percent cover is determined by counting the number of marks that lie directly over a piece of residue. For complete details on the line-transect method and worksheets for reporting percent residue cover please refer to the USDA National Agronomy Manual (pages: 503-126 to 503-127) found at http://www.nrcs.usda.gov.
For a more general estimate of crop residue cover, when reporting is not necessary, the photo-comparison method can be used. This involves comparing sections of the field that are representative of typical residue cover throughout the field and comparing them to photographs of known percentage cover. Example photographs and a more detailed explanation on this method can be found in Purdue University’s Agronomy Guide AY-269-W at https://www.extension.purdue.edu.
Harvest and planting are times to focus on residue management. The benefits of residue have led farmers to use less aggressive tillage to conserve some crop residue. Additional residue management options can be used in continuous corn systems.
1Eck, K.J., Brown, D.E., and Brown, A.B. 2001. Managing crop residue with farm machinery. Agronomy Guide. AY-280. Purdue University Extension.
2United States Department of Agriculture. Natural Resources Conservation Service. 2011. Residue and tillage management no till/strip till/direct seed. Code 329.
3Rasby, R. J., Drewnoski, M.E., and Stalker, A. 2014. Grazing crop residues with beef cattle. Publication EC278, University of Nebraska-Lincoln.
4Al-Kaisi, M. 2007. Tillage challenges in managing continuous corn. Iowa State University Extension. Integrated Crop Management.
5Al-Kaisi, M. and Hanna, M. 2009. Tips for managing corn residue in continuous corn. Iowa State University. Integrated Crop Management News. 6 Al-Kaisi, M.M., Hanna, M., and Petersen, T.S. 2009. Residue management and cultural practices. Iowa State University Extension, PM 1901a.