Remote sensing to monitor cover crop adoption in southeastern Pennsylvania

Abstract

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 (Zea mays L.) silage harvest and are strongly promoted for use in this niche. They are also planted following corn grain, soybean (Glycine max L.), and vegetable harvest. In Pennsylvania, the use of winter cover crops for agricultural conservation has been supported through a combination of outreach, regulation, and incentives. 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 green winter cover crop vegetation on agricultural fields and, when integrated with additional remote sensing data products, can be used to evaluate wintertime vegetative groundcover following specific summer crops. This study used Landsat and SPOT (System Probatoire d' Observation de la Terre) satellite imagery, in combination with the USDA National Agricultural Statistics Service Cropland Data Layer, to evaluate the extent and amount of green wintertime vegetation on agricultural fields in four Pennsylvania counties (Berks, Lebanon, Lancaster, and York) from 2010 to 2013. In December of 2010, a windshield survey was conducted to collect baseline data on winter cover crop implementation, 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). Satellite spectral indices were successfully used to detect both the amount of green vegetative groundcover and the amount of crop residue on the surveyed fields. Analysis of wintertime satellite imagery showed consistent increases in vegetative groundcover over the four-year study period and determined that trends did not result from annual weather variability, indicating that farmers are increasing adoption of practices such as cover cropping that promote wintertime vegetation. Between 2010 and 2013, the occurrence of wintertime vegetation on agricultural fields increased from 36% to 67% of corn fields in Berks County, from 53% to 75% in Lancaster County, from 42% to 65% in Lebanon County, and from 26% to 52% in York County. Apparently, efforts to promote cover crop use in the Chesapeake Bay Watershed have coincided with a rapid increase in the occurrence of wintertime vegetation following corn harvest in southeastern Pennsylvania. However, despite these increases, between 25% and 48% of corn fields remained without substantial green vegetation over the wintertime, indicating further opportunity for cover crop adoption.

Green Manure Comparison between Winter Wheat and Corn: Weeds, Yields, and Economics

“…Revenue from red clover silage was based on experimental yield and a 5-yr (2010-2014) average price received for alfalfa hay and haylage in six states (Iowa, Illinois, Michigan, New York, Ohio, Pennsylvania; USDA-NASS, 2016), adjusted for moisture. Corn silage was calculated with experimental yield and the Pennsylvania annual average market price (Ishler, 2013). Wheat revenue was calculated by multiplying experimental yield with a 5-yr average price of soft red winter wheat in Pennsylvania from 2008 to 2012 (USDA NASS, 2016).…”

“…Cover crops protect soil when a cash crop is not present, reduce potential runoff of soil and nutrients (Clark, 2007), scavenge nutrients not used by the cash crop (Shipley et al, 1992), and green manures can add N to the soil (Dou and Fox, 1994;Liebman et al, 2012). Cover crop adoption is increasing in Pennsylvania (Hively et al, 2015); in some areas cover cropping is subsidized and farmers can receive payments for no-till planting cover crops for the fi rst time, or for planting multi-species cover crop mixtures instead of single-species cover crops (NRCS, 2014;Columbia County Conservation District, 2015).…”

The 4Rs for cover crops and other advances in cover crop management for environmental quality

“…They concluded that intercropping selected legumes with switchgrass might enhance forage yield and quality and provide additional environmental benefits such as reducing fertilizer input and losses of fertilizer to air and groundwater. Hively et al (2015) studied the potential to use remote sensing to monitor cover crop adoption in southeastern Pennsylvania. Over the four-year study, their remote sensing analysis found that farmers are increasing adoption of cover crops following corn harvest.…”

A Model–Data Fusion Approach for Predicting Cover Crop Nitrogen Supply to Corn

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C over crop use in the mid-Atlantic and other regions of the United States has expanded in recent decades because they are an eff ective tool for reducing erosion and nutrient leaching and because they are a source of recycled N and fi xed N 2 for ecological nutrient management (Drinkwater and Snapp, 2007;Hively et al, 2015). However, it remains a signifi cant challenge to explain the variability and predict the outcome of N cycling processes across a range of cover crop management practices (Ketterings et al, 2015), leaving farmers with few tools to support adaptive N fertility management when using cover crops.

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