________
The commonality in these three no-till methods is that they never leave the soil bare and eliminate turning over of the soil. As our ancestors taught us, we learn about the Earth by observing and imitating her. The soil in the forest is never exposed; rather it is covered with humus, leaves, and growing plants. The forest does not stir up its earth; rather it enriches from above. In restoring degraded soils, it is essential that we heed these lessons.
CHAPTER FIVE
Feeding the Soil
Something slow moves through him, watched by hills.
Something low within each rock receives
His noonday wish, then crumbles rich; so fills
Each furrow that the prairie year upheaves.
His arm has lain with boulders. His copper hand
Has mused on roots, uncaring of barbed wire.
His fist has closed on thistle, and dug the land
For corn October snows have whelmed entire.
Something flows within him in stubborn streams,
And in the parted foliage something lives
In upright green, stirred by the rhythmic gleams
Of his hoe and spade. From worn-out arms he gives;
The earth receives, turns all his pain to soil,
Where he believes, and testifies through toil.
—JAMES A. EMANUEL, “For a Farmer”
Three distinct mounds of earth rested on empty feedbags in the middle of our circle of benches. We were gathered for a soils class during the Black Latinx Farmers Immersion, and the participants held notebooks in ready hands. “Put your notebooks down and go interact with the soil, find out its secrets. Use all of your senses. Get close,” the facilitator encouraged.
We looked, touched, and the braver among us smelled and tasted. After only five minutes we produced a detailed description of each soil. The first was gray, compacted, dense, waterlogged, sour tasting, and brittle. The second soil was friable, dark brown, slightly sweet in taste and smell, moderate in density, and sticky. The third soil was undecomposed, structureless, black, and smelled richly of humates. The participants, none of whom had studied soil, were able to accurately predict which would be best for growing annual crops and which needed amending.
We revealed that the first sample was the soil we found on this land when we arrived in 2006—heavy clay, rocky, impenetrable to tools. The third soil was what we found in the top layers of the forest—high in humus, rich, and young. The second soil was the one we created in partnership with nature over the years—a high-nutrient clay loam exploding with organic matter. We explained that the restoration of organic matter to the soil was part of healing from colonialism.
As European settlers displaced Indigenous people across North America in the 1800s, they exposed vast expanses of land to the plow for the first time. It took only a few decades of intense tillage to drive over 50 percent of the original organic matter* from the soil into the sky as carbon dioxide. Rich prairie loam soils that once held 8 percent organic matter or more were reduced to less than 4 percent on average. The productivity of the US Great Plains decreased 71 percent during the 28 years following that first European tillage.1 The initial anthropogenic rise in atmospheric carbon dioxide levels was due to that breakdown of soil organic matter. Cultivation and land clearing emitted more greenhouse gases than the burning of fossil fuels until the late 1950s.2
Restoring organic matter is a slow process, taking at least a decade to heal and only a year or two to undo. An acre (0.4 ha) of soil 6 inches (15 cm) deep weighs around 1,000 tons (900 MT), so increasing organic matter by 1 percent is a 10-ton (9 MT) change. It would be relatively easy if you could just add 10 tons of organic matter (straw, compost, leaves) and achieve that change, but the truth is that only 10 to 20 percent of what you add stays in the soil; the rest is broken down and released as carbon dioxide. So that amount of organic matter must be added year after year for it to return to precolonial levels.3
In this chapter we discuss how to care for the soil over the long term. We begin by exploring methods for testing the soil health, discuss how to make and use compost, share ideas for creating teas and inoculants that feed soil biota, and explore cover-cropping strategies that restore organic matter and nutrients to the soil.
There is a visible difference between the soils we have not amended with compost and organic matter (left) and those that we have stewarded for years (right).
Soil Tests
We can tell a lot about soil using only our senses and direct experience. Soil that is ready to receive our seeds is dark, moist, sweet swelling, crumbly, and teaming with biota. Soil that needs more love before we ask it to produce might be heavy with clay or depleted with sand, sour tasting, and devoid of life. One of the simplest low-tech soil tests is “texture by feel.”
Soil texture refers to the size and type of mineral particles in the soil. Soil’s inorganic portion is made up of sand, silt, and clay. Sand particles are the largest, at greater than 0.02 millimeter (mm) in diameter, and have the least capacity to hold on to water and nutrients. Clay particles are the smallest, at less than 0.002 mm in diameter, and have the highest capacity to hold on to water and nutrients. Silt particles are in between sand and clay in terms of both their size and their water- and nutrient-holding capacity. The ideal soil is loam, a balanced combination of all three textures.
Adding organic matter to the soil is part of decolonizing our relationship to land. Photo by Jonah Vitale-Wolff.
In order to determine soil texture by feel, you follow three basic steps that are reminiscent of making mud pies during childhood. First, see if a handful of the moistened soil can form a ball. Then determine if you can flatten the soil into a ribbon that can support its own weight, and measure the length of that ribbon. Finally, rub a bit of soil between your fingers and listen for its grittiness. The precise steps for texture by feel can be found on the Natural Resources Conservation Service website.4 The end result is a determination as to which of the 12 soil textures you have. If your soil is not loam, you will need to improve the texture by adding organic matter, such as compost and mulch.
One of the steps in the texture-by-feel determination is to form a ribbon with the soil and measure its length.
At Soul Fire Farm we have very heavy clay soils, which is a blessing in times of drought, but also a challenge in terms of water management. A few tips for managing clay soils:
Add 1 to 2 inches (2.5 to 5 cm) of finished compost annually to keep organic matter above 8 percent. Concurrently, monitor the levels of phosphorus, potassium, magnesium, and calcium to avoid overnutrification. Cover crops can be used instead of compost once optimal nutrient levels are attained.
Use permanent or semi-permanent raised beds so water drains into the pathways and infiltrates.
Complete all bed prep in the late fall, since the spring is too wet to work the soil.
Keep soil covered with cover crops or mulch at all times to prevent cementing.
UPLIFT
Indigenous Soil Testing in Africa
For millennia farmers in Africa have developed intricate processes for testing soils and nomenclatures for soil classification. For example, the original name of Egypt was Kemet, meaning “alluvial dark and fertile soils,” and the word deshret in ancient Egyptian was the name of desertic red soils.
Farmers in Africa classify their soils primarily based on productive capacity. Farmers test the soils by looking at environmental factors such as vegetation and fauna; topsoil morphology properties such as color, texture, density, and taste; and secondary factors including slope, workability, and stickiness.
Farmers rely on topsoil color and crop performance to assess nutrient levels. Topsoil’s color reflects its fertility level, as dark soils are generally more fertile than red, white, or beige soils due to their higher organic matter content. Farmers in Niger distinguish three color classes and relate these to land degradation: labu biri (black soil), which is most fertile and contains relativ
ely high levels of organic matter; labu kware (white soil), when through cultivation and erosion valuable nutrients are depleted; and labu kirey (red soil), the result of further degradation.
Texture is important to farmers to predict soil moisture-holding capacity. For instance, the Yoruba people in Nigeria rub soil between two fingers to tell whether it is Yanrin (sandy), Bole (clay), or Alaadun (loamy), or textures in between such as Bole alaadun (loamy clay). In the Mooré language (Burkina Faso), Bissiga means sandy soil, and is usually used for millet and vegetable crops; Bolé denotes clayey soils, suitable for sorghum and other crops that need more moisture. In terms of soil management, soils with coarse texture are easier to work with the hoe. They have a high infiltration rate but a low water-holding capacity.
Farmers use taste and smell to assess soil acidity and salinity. For example, farmers in Malaysia categorize soil on the basis of taste into tanah payau (sweet), tanah tawar (neutral), and tanah masam (sour) soil, relating fairly well to the Western concept of soil pH. Smell is used among a few of the Nigerian Yoruba people to determine “good” or “bad” soil.
Farmers use landforms to locate the topographic position of soils and estimate the risk of erosion. In the Mooré language the upper part of a slope is called zegedga, which denotes where erosion risks are high. In the Yemba language (Dschang, west Cameroon), soils of well-drained plains, called tsa’a pepeuo, are considered very fertile and are used for intensive agriculture. Poorly drained soils of inland valleys, tsa’a ngui, are used only for off-season crop production or grazing.
Farmers in Africa combine these soil characteristics to create complex soil classifications. For example, the Mamprusi people of the northeast of Ghana use the name Kokua sabli for dark soils with iron-manganese nodules and a general low fertility, especially in drought conditions. Dark-colored and sandy-textured soil found in the uplands are called Bihigu sabli. These soil categories correspond well with the soil classification of Western scientists.5
We aspire to be able to determine the chemical composition of our soils by taste as farmers in Nigeria do, but are still practicing that skill. We acknowledge that we have the privilege to live and farm at the top of the watershed and in the relatively pollution-free mountain foothills where tasting soil is feasible; one should not taste urban soils that might be contaminated with harmful chemicals. In the meantime we rely upon laboratory soil testing to give us further insights into soil health.
Table 5.1. Soul Fire Farm Soil Testing Results (using Modified Morgan Extractable method)
Your local agricultural extension agent or agricultural university will offer soil testing, usually at a reasonable cost. The test comes with thorough instructions about how to gather the sample as well as a guide for interpreting the soil test results. We like to test our soil every fall, when it is most depleted from growing food all season, and use that information to decide what amendments are needed. As you can see from our soil test results summary (table 5.1), we have had an overall positive impact on the soil health over time. It is possible for human beings to have a beneficial, mutualistic relationship with the Earth.
Depending on your soil testing laboratory, your results may come with recommendations to add inorganic chemical fertilizers to correct any “deficiencies.” We strongly encourage you to use organic, natural amendments in your soil.
pH
Soil pH is the measure of the acidity or alkalinity of the soil and one of the most important soil properties in that it affects the availability of nutrients. When soils are closer to a neutral pH, around 6.5, microbial populations increase and convert nitrogen, sulfur, and other nutrients into forms that plants can use. When the soil pH is too low, too acidic, limestone can be added to bring the pH up. There are two common types of limestone: dolomitic and calcitic. Dolomitic limestone contains magnesium and calcium carbonates and is slow acting over time. Calcitic limestone contains only calcium carbonate and is fast acting, but short-lived. If your soil is deficient in magnesium and requires a higher pH, consider dolomitic limestone. Occasionally pH needs to be lowered. Elemental sulfur is an effective amendment to acidify soil.
Macronutrients
Nutrients that the soil supplies in relatively large amounts are called macronutrients, and include nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. While each has its unique contributions to plant metabolism, and specific natural sources, all can be found in rich compost. We recommend that you begin by trying to manage most macronutrients with compost. If deficiencies persist, you can move to using specific amendments:
Nitrogen contributes to plant growth, and to seed and fruit production, because it’s a part of chlorophyll, the pigment responsible for photosynthesis. Nitrogen is also part of all proteins, thus essential for every metabolic process. Nitrogen lives in the soil for a short time, so we assume that it is almost completely depleted by the end of the season and amend accordingly. Nitrogen is supplied through leguminous cover crops (clover, vetch, peas), blood meal, composted manure, fish scraps, kelp meal, alfalfa meal, and bonemeal. In the northeast, where mineralization is slow in the spring, compost nitrogen release may be too slow to meet the needs of crops, making more soluble forms of nitrogen, such as blood meal, desirable.
Phosphorus is essential for photosynthesis and is involved in the formation of fats, sugars, and starches in the plant. It supports plant flowering and root growth. Phosphorus is supplied through rock phosphate, bonemeal, fish scraps, wood ash, and composted manure. Too much phosphorus can contaminate waterways and lead to eutrophication, a process of algae overgrowth that eventually deprives water ecosystems of oxygen.
Potassium supports the building of proteins and the process of photosynthesis in plants. It contributes to fruit quality and the plant’s ability to fight disease. Potassium is supplied by wood ash, granite dust, seaweed, fish scraps, greensand, and composted manure.
Calcium is an essential part of plant cell wall structure and facilitates the transport of elements throughout the plant. Calcium is supplied by limestone, gypsum, and seashell dust. Do not use limestone unless you wish to raise the pH.
Magnesium activates plant enzymes needed for growth and is essential to photosynthesis. Magnesium can be found in dolomitic limestone and Epsom salts.
Sulfur supports root growth, seed production, and cold resistance. It is supplied naturally through rainwater and is also found in gypsum and compost.
Alfalfa meal is sprinkled on the soil as an organic source of nitrogen. Photo by Neshima Vitale-Penniman.
Micronutrients
Nutrients that the soil supplies in relatively small amounts are called micronutrients or trace nutrients. These include boron, copper, chlorine, iron, manganese, molybdenum, zinc, and many others. Micronutrient deficiencies are most likely to occur in sandy, low-organic-matter soils or soils with a high pH. If your soil test reveals deficiencies in micronutrients, we recommend that you first try adding compost and correcting your pH. If deficiencies persist, contact your local gravel quarry and purchase rock dust—the powdery waste product that results when rocks are crushed. Rock dust has trace amounts of dozens of micronutrients and can be added safely to soil. Seaweed, kelp meal, and azomite are other natural sources of micronutrients. We do not recommend purchasing micronutrient amendments like manganese sulfate or chelated iron as these alter soil chemistry too quickly, acting like an energy drink rather than a nutritious meal.
Participants in the Black Latinx Farmers Immersion teach one another about macronutrients in a soil workshop. Photo by Neshima Vitale-Penniman.
Cation Exchange Capacity
Cation exchange capacity (CEC) is the measure of the soil’s ability to retain and supply nutrients. It is essentially the number of negatively charged binding sites on the soil that are ready to stick to the positively charged nutrients, including calcium, magnesium, potassium, ammonium, and others. The more clay and organic matter found in a soil, the higher the CEC. Soils with low CEC are more susceptible to los
ing nutrients through leaching. Forrest Lahens, a 2014 BLFI graduate, taught us to think of CEC in terms of a hip-hop metaphor in which Mos Def is like low-CEC soil that has few binding sites for nutrients because there’s just one vocalist in the project, while Wu-Tang Clan is like high-CEC soil that has more binding sites because there are more vocalists. CEC can be corrected through the addition of organic matter.
Lead
Lead is a dangerous element that can lead to birth defects and brain damage. If your lead test results are high, please refer to the previous chapter for remediation strategies.
Compost
Compost is proof of life after death. It is the original black gold and the primary way that our ancestors fed the soil. Among compost’s myriad talents, it improves soil texture and structure, increases soil’s moisture-holding capacity, adds macro- and micronutrients, controls erosion, protects against drought, buffers pH, stabilizes toxins, and controls weeds.
UPLIFT
African Dark Earth
African dark earth is a very dark and fertile anthropogenic soil invented by women in Ghana and Liberia 700 years ago. The creation of dark earth involves the combination of several types of waste: ash and char residues from cooking, bones from food preparation, by-products from processing palm oil and handmade soap, harvest residues, and organic domestic refuse. African dark earth has a high concentration of available calcium and phosphorus, likely due to the addition of animal bones. The bones in combination with the char also make the soil more alkaline, so it has a liming effect on soil chemistry.
Farming While Black Page 14
