Harnessing Cover Crops to Address Unique Farm Needs and Achieve Maximum Benefits
Sustainable Agriculture
Sarah Hirsh
Agent
University of Maryland
Princess Anne
Abstract
Cover crops can provide various benefits, such as building soil organic matter, scavenging nutrients, or controlling pests such as weeds. Since cover crops are not a primary source of farm income, farmers tend to spend less time planning and managing them when compared to cash crops. We hypothesized that designing cover crops with a particular purpose in mind, extending the cover crop growth window, and considering environmental constraints and the capacity of the farm and farmer would result in more productive and functional cover crops. In years one and two, respectively, Extension educators collaborated with 11 and 20 farmers to plan cover crops for 27 and 56 fields. Farmers managed cover crops and Extension educators measured cover crop fall and spring biomass, and spring nitrogen and carbon content. Fall cover crop biomass from 69 fields ranged from 28-2887 lb/acre, with an average of 521 lb/acre. Spring cover crop biomass from 83 fields ranged from 156-8659 lb/acre, with an average of 2213 lb/acre. Cover crop biomass positively correlated with spring growth days. Nitrogen in spring biomass from 56 fields ranged from 2-124 lb/acre, with an average of 37 lb/acre. Based on 56 fields, cover crop carbon to nitrogen ratio differed according to species composition, with grass and/or brassica cover crops > mixes that included a legume > pure legume cover crops. In conclusion, despite all farmers engaging in cover crop planning, cover crop biomass, nitrogen content, and carbon to nitrogen ratio greatly varied across operations. Extending the cover crop season was important for increasing biomass and functionality. In order to achieve the targeted purpose of the cover crop, farmers often had to modify plans and actively manage cover crops, for example through re-seeding, extending the season later than anticipated, or applying selective herbicides. We regularly communicated with collaborating farmers one-on-one and through having collaborating farmer networking meetings. Cover cropping strategies and results were shared at 10 field days to 278 attendees, 11 grower/agriculture service provider meetings to 876 attendees, four webinars to 86 live attendees and 232 subsequent “views,” and through being featured in two news articles.
Authors: Sarah Hirsh, Haley Sater, Dwayne Joseph, Shannon Dill, Jennifer Rhodes
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Sarah Hirsh Agent, University of Maryland Extension, Maryland, 21853
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Haley Sater Agent, University of Maryland Extension, Maryland, 21801
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Dwayne Joseph Agent, University of Maryland Extension, Maryland, 21620
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Shannon Dill Principal Agent, University of Maryland Extension, Maryland, 21601
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Jennifer Rhodes Principal Agent, University of Maryland Extension, Maryland, 21601