The LTAR common experiment in the upper Chesapeake Bay: cropland

Authors: Dell, Curtis; KARSTEN, HEATHER - Pennsylvania State University; Laboski, Carrie; ADAMS, TOM - Pennsylvania State University; Goslee, Sarah; Adler, Paul

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Dairy production is a key agricultural enterprise in the northern Chesapeake Bay watershed, and phosphorous (P) and nitrogen (N) losses from these farms can reduce water quality. Importing forages, grains, and mineral fertilizers increases quantities of P and N that must be managed. The Upper Chesapeake Bay (UCB) Long-Term Agroecosystem Research (LTAR) Cropland Common Experiment address these concerns by evaluating diverse crop rotations that minimize the need for imported feed, while maximizing year-round living ground cover, and alternative crop production methods that help to reduce nutrient losses or input requirements. A plot-scale experiment with diverse, six year crop rotation that includes manure injection, integrated pest management, and less frequent manure application is compared to a conventional diary forage production system (full replication of experimental treatments). The field-scale experiment has been used to monitor alternative production practices (manure injection and avoidance of neonicotinoid seed treatment tested to date) on a commercial dairy farm. Previous and ongoing findings suggest that crop rotation diversification and use of alternative management practices, such as manure injection and integrated pest management, have potential to increase the economic and environmental sustainability of dairy cropping systems.

Technical Abstract: Dairy production is a key agricultural enterprise in the upper Chesapeake Bay basin, where phosphorous (P) and nitrogen (N) loading contribute to eutrophication. Import of forages and grains and application of mineral fertilizers contribute to nutrient imbalances in the basin. The Upper Chesapeake Bay (UCB) Long-Term Agroecosystem Research (LTAR) Cropland Common Experiment aims to evaluate diverse crop rotations that minimize the need for imported feed, while maximizing year-round living cover, and alternative crop production methods that help to reduce nutrient losses or input requirements. UBC’s plot-scale experiment was established in 2018, incorporated an ongoing cropping system study that was established by Penn State University in 2010. An alternative dairy cropping rotation (including silage and grain corn (Zea mayes L.), alfalfa (Medicago sativa L.)/orchardgrass (Dactylis glomerata L.) mix, winter rye silage (Secale cereale L.), and sorghum-sudangrass (Sorghum × drummondii (Steud.) Millsp. & Chas)) that employed manure injection, integrated pest management, and less frequent manure application was compared to a prevailing, conventionally managed silage corn/alfalfa rotation with more frequent manure application. A field-scale experiment was also established in 2019 to monitor alternative production practices (manure injection and avoidance of neonicotinoid seed treatment) and prevailing practices in three fields on a commercial dairy farm. Previous and ongoing findings suggest that crop rotation diversification and use of alternative management practices, such as manure injection and integrated pest management, have the potential to increase the economic and environmental sustainability of dairy cropping systems, but long-term evaluation is needed for confirmation.