|HIVELY, DEAN - Us Geological Survey (USGS)|
|DUIKER, SJOERD - State College Of Pennsylvania|
Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2015
Publication Date: 11/1/2015
Citation: Hively, D., Duiker, S., Mccarty, G.W. 2015. Remote sensing to monitor cover crop adoption in southeastern Pennsylvania. Journal of Soil and Water Conservation. 70:340-352.
Interpretive Summary: Winter cover crops are planted at the end of the summer row-crop growing season, and provide living ground cover throughout the winter season. This vegetation helps to reduce soil erosion and phosphorus loss, and also accumulates residual soil nitrogen into its biomass, reducing the risk of wintertime leaching of agricultural nitrogen to groundwater. In the Chesapeake Bay watershed, particular focus is placed on the use of winter cover crops as conservation practices for nutrient and sediment control. The agricultural region in southeastern Pennsylvania contributes a large portion of nutrient and sediment loads to the Chesapeake Bay, via the Susquehanna River, and is an important area for agricultural conservation implementation. This project used satellite imagery in conjunction with windshield surveys to evaluate the extent and amount of wintertime vegetation on corn fields in four Pennsylvania counties (Berks, Lebanon, Lancaster, and York), from 2009 to 2012. Between 2009 and 2012 the occurrence of wintertime vegetation following corn increased by 94% in Berks county, 48% in Lancaster, 58% in Lebanon, and 109% in York. Apparently, efforts to promote cover crop use in the Chesapeake Bay watershed have coincided with a rapid increase in the occurrence of wintertime vegetation on corn fields in southeastern Pennsylvania.
Technical Abstract: In the Chesapeake Bay watershed, winter cereal cover crops are often planted in rotation with summer crops to reduce the loss of nutrients and sediment from agricultural systems. Cover crops can also improve soil health, control weeds and pests, supplement forage needs, and support resilient cropping systems. In southeastern Pennsylvania, cover crops can be successfully established following corn silage harvest, and are strongly promoted for use in this niche. They are also planted following corn grain, soybean, and vegetable harvest. The use of winter cover crops for agricultural conservation has been supported through a combination of outreach, regulation, and incentives, and on-farm implementation is thought to be increasing, but the actual extent of cover crops is not well quantified. Satellite imagery can be used to map winter cover crop biomass and vegetated ground cover on agricultural fields and, when integrated with additional remote sensing data products, can be used to evaluate winter ground cover following specific summer crops. This project used Landsat and SPOT satellite imagery, in combination with the National Cropland Data Layer, to evaluate the extent and amount of wintertime vegetation on corn fields in four Pennsylvania counties (Berks, Lebanon, Lancaster, and York), from 2009 to 2012. In December 2010, a windshield survey was conducted to collect baseline data on implementation of winter cover crops, with particular focus on identifying corn harvested for silage (expected earlier harvest date and lower levels of crop residue), versus for grain (expected later harvest date and higher levels of crop residue). Results of annual satellite analysis showed consistent increases in wintertime ground cover over the four-year study period, indicating that farmers are increasing adoption of this important conservation practice. Between 2009 and 2012 the occurrence of wintertime vegetation following corn increased by 94% in Berks county (from 34% to 66% of corn fields exhibiting vegetation), 48% in Lancaster (from 50% to 74%), 58% in Lebanon (from 40% to 63%), and 109% in York (from 23% to 48%). Apparently, efforts to promote cover crop use in the Chesapeake Bay watershed have coincided with a rapid increase in the occurrence of wintertime vegetation on corn fields in southeastern Pennsylvania. However, despite these increases, between 26% and 52% of corn fields remained without living vegetation over the wintertime, indicating further opportunity for cover crop adoption.