Soil Restoration is important. I don’t always understand the science behind good garden practices, but an afternoon with Ben Grosscup helped me think about my soil in new ways. Grosscup began working with the Northeastern Organic Farming Association NOFA) right out of college. He was part of the efforts to organize putting bans on Genetically Modified Organisms (GMOs) and efforts to label foods if they did include GMO’s. He organized educational events and seminars for farmers and others interested in the quality of our food supply. Over the years he learned about carbon restoration of our soil.
I went to see Grosscup’s in-town half acre garden to get a better understanding of what carbon restoration means and the role of microbes in the soil. The first thing we did was look at the cover crops, radishes, vetch and winter rye, that Grosscup planted after his vegetable crops were harvested. “I plant a variety of cover crops in one space because each species of plant calls a different microbial community,” he said.
I had understood that cover crops like radishes, winter rye, peas, and oats had enough time in late summer to cover the soil over the winter protecting it from erosion while the roots went deep in the soil to bring up valuable nutrients. I also knew that winter rye would send up shoots that survived the winter and continueto grow in the spring while annual crops like peas and oats would die.
I did not understand how you could plant in a bed that was full of winter rye in the spring or any other cover crops. All was about to be revealed. First, there are two types of cover crops, perennial and annual. Winter rye is a perennial crop in that will survive the winter and continue to grow in the spring. When it is nearly time to plant new vegetable crops in the spring Grosscup pulls up the winter rye, covers the bed with newspapers and lays the harvested winter rye on top. He supplies the newspaper barrier to prevent the rye from re-rooting.
He uses three techniques when planting the newspaper covered rows. First he waters the newspaper well, and the soil beneath. Then he can puncture little holes in the newspaper and insert his vegetable starts. Or he can plant his hills of cucumbers, squash, or beans by making the holes in the paper for the seeds. Or he can create a shallow long trough through the paper to plant seeds. As in any planting he needs to keep it well watered until the seeds or young plants are well established.
Annual ground covers like peas and oats will not survive the winter. Their roots will bring up nutrients and the dead plants will compost in place giving organic matter and nutrients back to the soil.
There are three goals: to cover the soil and protect it from erosion, to enrich the soil, and to avoid disturbing the soil which would release carbon into the atmosphere.
We all have to remember that soil is alive. It is full of fungi, bacteria, nematodes and many other invisible creatures. It has been estimated that a teaspoon of healthy soil contains more microbes than there are people on earth. Grosscup explained that these creatures need sugars created by photosynthesis.
Of course I needed to give myself a little review course about photosynthesis. Chlorophyll in green plants takes the energy from sunlight to break up the water (H2O) molecules in the plant. The plant breathes some of the oxygen back into the atmosphere. The saved molecules are bound to carbon dioxide molecules (CO2) to ultimately create simple carbohydrates like glucose (C6H1206). “These sugars are exudated into the soil through the plant’s roots” Grossup said.
“What the microbes give back to the soil is the ability to metabolize the crystalline formations (stones) that are a part of the soil and turn them into a biologically active substance like trace minerals that are important and usable by the plant.”
The tools of what we now call conventional agriculture include fertilizers which are attempting to give the soil the nutritional elements that plowing and tilling has removed. We gardeners see this when we buy a bag of fertilizer and notice the identifying NPK numbers 5-10-5 or 5-4-1 which refers to the percentage of nitrogen, phosphorus and potassium in that fertilizer. What these fertilizers do not do is provide food for all the microbial life in the soil which is so vital.
Grosscup has a large sunny vegetable garden next to his house. He says he and his partner rarely have to buy vegetables, and they have three chickens to provide eggs, and compost. They also have fruit trees and berries, as well as a section they call a pollinator garden, filled with perennial flowers that attract bees and other pollinators.
The sloping area in back of the house is very much a project in progress. Norway maples were taken down and removed. Some spaces have been covered with cardboard to kill all the weeds growing in the area. Other spaces are farther along in the process and have been planted with annual cover crops with the intent they be ready for planting in the spring. Other areas have been planted with honeyberries, gooseberries and goji berries and a few fruit trees. The ground around them has also been planted with annual cover crops to keep building the soil.
I always say the garden path leads to many fields. This week I explored a path that led into some fascinating science.
Between the Rows October 14, 2017