Sunny Slope Orchard

Sunny Slope Orchard
In the coast range foothills overlooking the Sacramento Valley

Sunday, October 24, 2010

Feeding the Soil

Throughout the spring and summer our trees have flourished, drawing nutrients from the soil to produce vigorous growth and loads of fine fruit. Now, as the long dry summer comes to an end it's time for us to give back to the soil to restore it for next year's crops. Rather than relying upon synthetic chemical fertilizers we follow the organic practice of fostering nature's method of nutrient cycling.

In the natural world plants take up nutrients from the soil and convert them into roots, stems, leaves and seeds. The plants then die or shed their leaves onto the ground where they become food for a wide range of microbial life. Molds, fungus, bacteria, earthworms, and insects small and large break this vegetable matter down into nutrients available for future plant growth. In an undisturbed environment like a forest this cycling of nutrients is perpetual, from soil minerals to plant matter to microbial and animal life and back to the soil. In organic agriculture we do our best to mimic and enhance this natural method of nutrient cycling. In fact the rules of organic certification require not just avoiding synthetic chemicals but taking steps to actively improve soil health.
Spreading compost on the orchard floor

Our main methods are: annual soil tests by an agricultural soil testing laboratory, heavy applications of compost, planting a cool season cover crop in the orchard floor, and mowing the cover crop down to leave a mulch in late spring. So every year about this time, before the first fall rains, we spread 24 tons of high nutrient compost evenly over the orchard floor. This material is produced in Yolo County from recycled yard and farm waste, composted to maximize nutrients and microbial life and certified for use on organic farmland.

My home built planter sowing cover crop seed

Next we plant a cover crop mixture of bell beans, field peas, and vetch. These are all legumes, wonderful plants that take nitrogen from the air and store it in their roots where it will be available to successive crops. Other benefits of cover cropping are prevention of erosion, increasing soil porosity via deep tap roots, and increasing water storage in the soil by reducing rain runoff and raising levels of organic matter in the soil. At the same time the cover crop is a major tool in insect pest control. These legumes all bloom heavily in the spring, attracting many types of beneficial insects to the orchard which then help control pest species.

Since we depend almost entirely on rainfall to sprout and grow the cover crop, timing of planting and generous fall storms are critical to success. I'm happy to report that as I write this, just days after spreading compost and planting, the weather gods are coming through for us with the first big storm of the season. 2 1/2 inches of rain so far with more on the way. Sometimes things just work out right!