Cover Crop Benefits for Bees and Soil

Productive and profitable farming is both a short-term and long-term effort. Incorporating cover crops into your orchard management plan is a useful tool for growers to achieve their goals. This article will revisit the benefits of cover crops. Next month I will present some tips for increasing its success.  
 
Cover crops not only contribute to healthy honey bee colonies and ensure robust pollination services for this years’ nut set but also help build healthy soil that contributes to orchard and crop vitality for the years to come.  

The decision to manage a cover crop on your orchard floor can be a daunting task. Adding this tool to your toolbox does come with its own challenges. There is a required learning curve when changing your management style to accommodate any new technique. 

Building Soil Health
Choosing the right plants can have a significant impact on soil issues like compaction, erosion, weed control. Cover crops penetrate hard ground with their roots and hold the soil together by creating stronger aggregates, which also increases water infiltration and prevents erosion. Nitrogen-fixing legumes like clover and vetch can add about 80 lbs. of nitrogen per acre to the soil. 
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Recently growers have been facing issues with compaction. As orchards with a high clay content lose their organic matter, the pore size in between small bits of aggregated soil decrease. This decreases the soil's porosity which slows the orchards ability to soak up water. Factors like vehicle weight, tire surface area, and frequency of passes will affect the depth of compaction.  Water, whether rain or sprinkler irrigation, adds to compaction by lubricating soil particles and forcing them closer together.   

Cover crops will restore your orchard. The deep roots of living cover crops create spaces and channels in the soil which increase water infiltration. After mowing or disking, the decomposing plant matter will increase the organic matter content which will prevent soil compaction and its adverse effects. As organic matter decays, nutrients are released and are available to succeeding crops. Sandy soils benefit greatly from cover crops because organic matter holds more than 18-20 times its weight in water. Just 1% organic matter in the top six inches holds up to 27,000 gallons of water per acre. [1] 

Cover crop mixes like this brassica help jumpstart bee colony population and vigor early so they will be ready to attack those blossoms and set nuts when almonds bloom!

Benefits to Bees
While cover crops influence soil health, they provide blooming forage at the right time to significantly increase the pollination potential of the honey bees hired to set nuts. Timing and preparation matter. Planting brassicas like mustard, radish, and canola early in October will allow them to provide critical nutrition to the hungry bees awaiting the almond bloom.   
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Growers with early blooming insect-pollinated crops like almonds can also use cover crops to feed bee colonies. The majority of the 2.7 million colonies in the US are shipped to almond pollination in January, a time when colonies have not had forage for months and are naturally at their weakest. Although there may be warm days in January and February, California’s central valley doesn’t provide any blooming plants. Colonies must patiently wait for the nectar and pollen resources of almond bloom to appear.  

When foraging bees bring back the first pollen of the new year the bees inside the colony begin to rear larvae. These larvae emit a pheromone which stimulates more foraging bees to seek out flowers and pollinate them. This positive feedback loop will continue if resources are available.  
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A brassica cover crop mix seeded in the fall, like our Seeds for Bees Mustard mix, will bloom 2-6 weeks before almonds, providing critical nutrition at a time when it benefits growers the most.

Research shows colonies reared in pollen limited conditions produce workers that forage less often and are less efficient at communicating [2], which could have a significant impact on yield.  

The many benefits of cover crops are smart farming for soil, water, and enhanced pollination. Seeds for Bees grower Blake Davis has seen his orchards improve significantly since enrolling in the program. He explains, “Our soils are heavy and can become compacted. Cover cropping with the PAm Mustard Mix has helped the water infiltrate by breaking up the soil and adding organic matter”.

For more information on how you can promote sustainable farming and enhanced honey bee health, contact me at billy@projectapism.org or by calling 916-287-3035.

References:  

1. USDA NRCS (2013) Soil Health Key Points
   
2. Scofield HN, Mattila HR (2015) Honey Bee Workers That Are Pollen Stressed as Larvae Become Poor Foragers and Waggle Dancers as Adults. PLoS ONE 10(4): e0121731.