On our farm, the orchard floor is the gateway to harnessing the tremendous power of living soil. We look at increasing the capacity of our farm’s ability to hold carbon through healthy plants and soil humification as having significance that reaches beyond our little corner of the world.
In conventional orchard settings, the orchard floor is a place where weeds grow and compete with trees for water and nutrients. Below this floor is the soil, viewed largely as a place where nutrients and moisture reside in sufficient or insufficient quantity. This view dictates an approach to orchard floor management which revolves around weed control in the form of an herbicide strip under the trees to keep them weed free, and soil amendments in the form of soluble synthetic fertilizers combined with irrigation to keep the soil moist. The alley ways are planted with grass and kept mowed tight, like a lawn for ease of equipment operation.
Our approach is more complex and integrated.
At the core of this work is increasing soil health through increasing soil organic matter, soil life and soil energy. One of the primary ways we do this is through the direct addition of fungal compost: medium-high carbon materials like ramial wood chips, bark mulch and straw breaking down slowly with out heat in an unattended heap until it is filled with mats of white mycelium. We try as much as we can to use materials that are either a direct or indirect diversion from the waste stream.
It also informs our choice to use mulch for weed suppression under the trees. Mulch suppresses competition with the tree’s feeder roots. It also help keep the soil moist.
We are experimenting with using a combination of hardwood bark chips from a local sawmill and high carbon hay cut from valley fields where we will spread compost from our project composting our local school’s food waste.
Throughout the growing season some of the material breaks down into the soil. But much of it remains. In the late fall, after the leaves have fallen, we rake the mulch away from a narrow 24″ strip between the trees.
We have two objectives here. The first is mice and voles! The orchard floor MUST be trim and bare going into the winter so there is no place for the critters to live. They will girdle and kill baby trees and 50 year old trees alike. (We’ve learned this the hard way)
The second objective is to mix the fallen leaves with the already decomposing mulch and move them to the drip edge of the tree where we can mow them up. Ironically, we call this orchard ‘sanitation’. The process causes the the leaves, which have dormant spores for pathogenic diseases, to be rapidly broken down by soil organisms. This drastically reduces disease pressure in the orchard for the next growing season and is a key component of our disease management program.
We are still looking for ways to improve this system. Though it accounts for only a small percentage of the orchard floor, we don’t like leaving bare strips over the winter. Could we rake the mulch away in late August and seed a fast growing cover crop which would winter kill and leave a light residue? These are problems that need tweaking.
Another element we strive for in our orchard floor is a diverse forest edge/meadow ecosystem, a mix of grass and plants (weeds) which flower throughout the growing season and provide a continuous source of food for native bees and habitat for predictor insects. We practice a minimal amount of selective mowing: letting the alley ways grow up, flower and seed. This maximizes the carbon content of the mow-ings being returned to the soil and allows native plants to thrive amidst the grass.
Even at harvest time, there are some lovely fall flowers blooming beneath the fruit laden boughs!
Organic orchard ground cover management in the temperate North East is a new and challenging frontier. There is no template to follow and a lot of what we are doing is experimental and evolving. We are so excited and lucky to be part of a brilliant and creative group of colleagues called the Finger Lakes Fruit Geeks, who meet and share ideas and collaborate on on-farm research projects, inspiring and motivating each other to innovate and take risks. Some of these other farmers are: Good Life Farm, Red Byrd Orchard and Mike Biltonen at Apple Leaf.