What is Soil Loss?
Soil loss can ruin a civilization. As we lose healthy soil, the nutrients in food decrease, the amounts of food that can be grown decrease, and the land risks becoming desertified, over salted, or otherwise barren.
Though globally we are experiencing soil loss at a high rate, with proper land management we can help reverse soil loss. It takes work and education, but there are many people working to not only stop soil loss, but to reverse it.
Buying local food from a small sustainable farmer, as well as growing your own compost and gardens at home, can help you to make a small difference in improving our soils.
The Facts about Soil Loss
The World Wildlife Federation estimates that we have lost half our fertile topsoil in the last 150 years. Soils are eroded, losing organic matter, and have less nutrients than before.
As soils lose organic matter, they are more prone to erosion via wind and rain. Fifty percent of the world’s land surface is devoted to agriculture, with a third to crops and two thirds to grazing. Cropland is most susceptible to erosion because it is cultivated so frequently.
Cropland can lose up to 10 metric tons of soil per hectare each year. Grazing lands lose 6, while forests lose as little as 0.004 to 0.05 metric tons. Bare soil means more erosion, and cropland that is not covered with living or dead plants is more susceptible.
As soil erodes, it carries nutrients and organic matter with it. Farmers apply fertilizers and manure to replace what is lost, but this costs a lot of money. Poorer farmers can’t apply enough to make up the difference.
An inch of topsoil can take several hundred years to develop naturally. In the US, we are losing topsoil 10 times faster than we can replenish it.
Soil erosion drives climate change. Less life in the soil means less carbon storage. In fact, better soil management could reduce global greenhouse gas emissions by humans from 5 to 20%!
Soil loss leads to less nutritious food for us, and more sediment in our waterways. Fortunately, new farming techniques are being used to try to slow down or reverse soil losses.
Combating Soil Loss
Better farming practices can help slow soil loss. There are many methods out there that farmers are trying to use. After all, better soil means better yields for the farmers too!
Healthier soil means healthier plants and animals. The plants grow better, are bothered by less pests, and the soil can hold more water, meaning they need less irrigation.
Leaving crop residues in the fields after harvest can slow erosion and allow the residues to break down, adding organic matter to the soil.
Growing cover crops works even better, as live plants can build soil, slow rainfall, and even fix nitrogen into the soil.
Crop rotations can improve fertility and reduce erosion of soils. Different crops have different needs and can return nutrients to the soil for different crops later.
Farming on contour means planting along the slopes in a way that stops rainfall from flowing downhill quickly. Adding hedgerows of perennial or annual plants can also slow rainfall.
Some researchers are looking into perennial versions of our annual plants. Perennial means they live from year to year, thus there is no bare soil to erode, and stronger root systems to maintain soil.
Polycultures are mixes of plants that can grow together. Though a large farm might have a hard time harvesting a mix of plants, the more species you have, the more beneficial insects and microbes you can have on your farm.
Mixing animals and crops is a great way to spread manure and have animals do a lot of work for you. They eat weeds, add manure sustainably (rather than in manure pits to be managed), and can help till the soil.
Fortunately, here in the Chesapeake Bay area, we have been losing less soil recently due to voluntary changes to how we farm. This helps the farmers and improves nutrient and sediment problems in the Bay.
What You Can Do to Reverse Soil Loss
It’s easy to ignore soil issues when you aren’t a farmer. Though it’s great news that our local farms are improving, there are many poor farmers worldwide where the news isn’t so good.
In the tropics, where the majority of humans live, they contend with warmer temperatures and higher rainfall, leading to soils that deplete much faster than in temperate zones.
Buying your food locally means you can buy from farms that raise their crops and animals more sustainably. They may mix animals and vegetable crops. They are often smaller, so they can intercrop more successfully than farmers that depend on mechanized harvesting.
Our small local farmers know that quality, rather than quantity, is important to their customers. Therefore they will farm organically, whether certified or not, and take care with their soil to maximize harvests. Growing a variety of foods help maintain diversity on their farms.
At home, in your yard, you too can help with soil loss. Whether you garden or not, if you have a yard, you can work to help eliminate erosion. Older neighborhoods have not been built to minimize erosion, but newer ones often have.
Maryland Stormwater Regulations don’t allow new houses to be built without stormwater management in place. Unfortunately, those new neighborhoods are often devoid of vegetation and trees. Though your stormwater may be managed, the soil isn’t fertile.
If you live in an older neighborhood, look to see where the rainfall goes when it rains. Are your downspouts sending water to the road or your yard? Is there flooding nearby? For both new and old houses, taking control of your own stormwater can help soil loss and nutrient issues in the Bay.
Building rain gardens, finding ways to capture rainfall from your roof or driveway, and planting more trees and shrubs can all help increase fertility, improve the water holding capacity of your soil, and to decrease soil losses from your land.
If you garden, using rainwater rather than irrigating will save you money over time. Better soil will hold that rainwater for longer, meaning less need to irrigate. Your plants will be healthier with less fertilizers, irrigation, and pesticides.
The Bay-Wise Yardstick program through the University of Maryland Extension can help you learn how to improve the Bay at home, along with improving your yard and soil quality!
Soil loss is a real threat to food security and livelihoods of people all over the globe. It may be easy to ignore if you aren’t a farmer or gardener, but soil loss affects us all.
Less nutritious food and higher food prices comes with soil loss, whether we realize it or not. Sediment loads in our waterways cause problems with fishing.
Buying our food from farms that practice proper soil management is important. So is minimizing our own effects in our own yards!