Inadequate soil is one of the main reasons fruits, vegetables, and flowers struggle to grow to their full potential. Land plots of any size, from large farms to backyard gardens, will need fertile soil in order to produce healthy yields. Organic fertilizers and can add a needed boost, but they can be expensive, especially in large quantities. Luckily, growing the right plants with the right techniques can enrich soil by pulling elements and nutrients directly into the dirt.
What Makes Healthy Soil?
Organic materials are the key ingredients for healthy soils, which in turn make healthy plants. Farmers and gardeners will focus on the “N-P-K” (Nitrogen-Phosphorus-Potassium) ratio of plants and fertilizers to help boost certain crop growth. Nitrogen needs to be replenished the most, making it one of the more important elements to consistently add to your soil.
Nitrogen fixing plants are essential for working gardens and farms. Many are used in the form as cover crops. As they decompose, they raise the amount of accessible nitrogen in soil for other plants to use. These “nitrogen-fixers” have a symbiotic relationship with bacteria that other plants do not, making them highly useful for depleted soil.
Types of Cover Crops
Cover crops are specific plants grown in between planting seasons to give depleted soils much needed rest, nutrient boosts, and to help improve their structure. Cover crops are different from food crops in that they are cut back or killed before going to seed so that their useful energy is put back into the land. Some cover crops fix nitrogen, while others are great ways to add bulk organic matter via biomass (leaves and foliage), and some do both. Cover crops can also act as a layer of nutrient-rich mulch to spread over crops (hence their name), which not only control weeds but will continually slow-release nutrients into the soil as they decompose.
Clover in general is a well-known and often used cover crop, since their foliage adds a specifically high amount of nitrogen compared to other plants when they decompose. Clover is usually planted in autumn and chopped up into spring soils a few weeks before planting. Crimson clover and red clover are the most popular varieties depending on region to help with nitrogen-fixing, moisture retention, and weed prevention.
Other legumes like cowpeas, soybeans, and alfalfa are also nitrogen-fixers and can be planted at different times of the season to keep a garden or farm continually active. They often will grow in shade and are hardy plants that can be used in crop rotation, as soil-builders, or as forage crops.
These plants are known to grow well in poor soils and help revive soil quality as they grow year after year. Most will have deep taproots which bring nutrients buried too far down for most plants to access back up to the surface. You can also cut them back frequently and use the biomass to return organic material and nutrients back into the soil as they decompose.
Known as the work-horse of soil-builders, comfrey is one of the most commonly used plants for rejuvenating the soil quickly. Its root systems can extend over six feet underground, collecting deeply buried nutrients and summoning them back to the surface in its foliage. It also provides a high amount of biomass in mere months, as it regrows its leaves quickly after being cut back.
These perennials are also nutrient-hunters, but as their name implies, they can sting your bare skin. If you’re willing to take on the challenge, make sure to dress appropriately when cutting these back. The effort will be worth the nutrient-rich organic material that goes back into your garden.
This edible plant is often considered a weed, but has many virtues savvy gardeners revere. Its deep root system pulls nutrients up to the surface and can be chopped or tilled back into smaller gardens.
This “nitrogen-fixer” acts like clovers and legumes, and it's very hardy. Mature plants will grow to eight feet high which means they also yield a high amount of biomass—you can cut them down numerous times during the growing season.
Crop Rotation and Forage Crops
Farmers use crop rotation by subsequently planting different crops in the same area to help replenish nutrients. A very common example is planting soybeans following a season of growing corn, as the soybeans are a nitrogen-producing plant whereas corn is a heavy nitrogen user. Crop rotation also helps reduce soil erosion and improve soil structure.
Forage crops are plants left for nature to use, mainly through foragers like livestock and other wildlife, instead of being tilled or used as mulch. When used in crop rotation practices, forage crops can improve soil by enriching and adding fertility, breaking up clay, and preventing soil erosion.
Depending on what your garden or farm needs most, the right kind of forage crop can either fix nitrogen or add much needed organic material. Food crop legumes like peas and beans are nitrogen-fixers that will enrich the soil. Grains like rye, wheat, barley, buckwheat, and oats will add bulk organic material. Daikon radishes grow well in clay soils, breaking them up as they decompose—this adds much needed pathways for water and nutrients to enrich soil structure. Many gardeners and farmers try a mix and match approach to find a balance of the benefits between grains and legumes.
Consider how much biomass you can deal with, and how much nitrogen the soil needs, and only plant what you can manage with your tiller and space requirements. Soil tests can be a helpful tool to find out what new plots and overworked farmland may require. Once you figure out what your land needs, you can develop a rhythm of planting the right things every year to make sure your soil is always healthy.