No-till farming, also called zero tillage or direct drilling, is a farming method used to grow crops or grass without turning over the soil. This technique helps reduce soil erosion caused by traditional farming methods, especially in sandy or dry soil on hillsides. Other benefits may include more water soaking into the soil, better storage of organic material in the soil, and improved movement of nutrients. These methods can also support more types of life in and on the soil. In traditional no-till farming, farmers use herbicides to control weeds. In organic farming, they use other methods, such as planting cover crops to cover the soil and stop weeds from growing.
There are three main ways to practice no-till farming. "Sod seeding" involves planting crops using machines into a sod, which is created by using herbicides to kill a cover crop. "Direct seeding" means planting crops through the leftover material from a previous crop. "Surface seeding" or "direct seeding" involves placing seeds on the soil's surface. On flat land, this method requires little or no machinery and minimal work.
No-till farming can improve crop growth and increase harvests. However, farmers who want to use this method may face challenges. Existing farms might need to learn new skills, buy new tools, and adapt to changes in their fields. One major challenge, especially for grain crops, is that farmers can no longer rely on burying crop residue deeply to control pests and weeds. Instead, no-till farmers must use chemicals, biological pest control, cover crops, and more careful field management.
Tillage is still widely used in farming today, but no-till methods may work well in certain situations. Some farmers use a mix of tillage and no-till methods, such as minimum tillage or "low-till." For example, some approaches use shallow digging with tools like a disc harrow but avoid plowing, or they use strip tillage.
Background
Tillage is a farming method that prepares soil by using machines to mix it, often removing weeds that grew in the previous season. Tilling can create a flat area for planting seeds or shape the soil into rows or raised beds to help plants grow better. This technique has been used for a very long time, with clear evidence of its use dating back to at least 3000 B.C.
No-till farming is different from conservation tillage and strip tillage. Conservation tillage includes practices that reduce how much soil is tilled. No-till and strip tillage are both types of conservation tillage. No-till means not tilling the soil at all. Tilling the soil every other year is called rotational tillage.
Tillage can cause problems such as soil compaction, loss of organic matter, breaking down of soil clumps, damage to soil microbes and other living things like mycorrhizae, arthropods, and earthworms, and soil erosion, which happens when topsoil is washed or blown away.
Origin
No-till farming is a mix of methods that evolved over time, with many techniques linked to traditional market gardening practices in places like France. An organized effort to stop plowing began in the 1940s, led by Edward H. Faulkner, who wrote the book Plowman's Folly. In this book, Faulkner criticized the use of a specific type of plow called the moldboard plow but did not oppose shallow surface tilling. After World War II, the invention of strong herbicides like paraquat allowed scientists and farmers to experiment with no-till methods. Early users of no-till farming included Klingman (North Carolina), Edward Faulkner, L. A. Porter (New Zealand), Harry and Lawrence Young (Herndon, Kentucky), and the Instituto de Pesquisas Agropecuarias Meridional (Brazil, 1971) with Herbert Bartz.
Adoption across the world
Land used for no-till farming has grown worldwide. In 1999, about 45 million hectares (170,000 square miles) of land used no-till farming globally. This increased to 72 million hectares (280,000 square miles) in 2003 and to 111 million hectares (430,000 square miles) in 2009.
According to the Australian Bureau of Statistics (ABS) Agricultural Resource Management Survey, in Australia, 26% of agricultural land used no-till farming methods between 2000–01. This increased to 57% between 2007–08. By June 30, 2017, 79% (or 16 million hectares) of 20 million hectares of crop land was not tilled. Similarly, 70% (or 2 million hectares) of 3 million hectares of pasture land was not tilled, except for sowing.
South America had the highest use of no-till farming globally in 2014, accounting for 47% of the world’s no-till farmland. The countries with the highest use were Argentina (80%), Brazil (50%), Paraguay (90%), and Uruguay (82%).
In Argentina, no-till farming reduced soil erosion by 80%, cut costs by more than 50%, and increased farm incomes. In Brazil, no-till farming reduced soil erosion by 97%, improved farm productivity, and increased farm incomes by 57% five years after adoption. In Paraguay, net farm incomes rose by 77% after using no-till farming.
No-till farming is a soil conservation method used in the United States. Its use has grown because it can lower costs and improve soil health. By reducing soil disturbance, no-till farming decreases the number of times machinery must pass over fields, lowering fuel and labor costs. Keeping crop residue on the soil also reduces water evaporation, increases water absorption, and improves soil moisture.
According to the 2017 Census of Agriculture, about 21% of U.S. cropland used no-till farming. By 2023, this increased to roughly 30%, showing a growing shift toward conservation tillage.
A legislative bill, H.R.2508 of the 117th Congress (also called the NO EMITS Act), was introduced in 2021 by Representative Rodney Davis of Illinois. The bill aims to update the Food Security Act of 1985 and proposes strategies like minimal or no tillage to reduce agricultural emissions. H.R.2508 is currently being reviewed by the House Committee on Agriculture and is supported by Representatives Eric A. Crawford of Arkansas and Don Bacon of Nebraska. The bill suggests offering financial and mechanical help to farmers transitioning to conservation practices and funding for Conservation Innovation Trials.
U.S. farmers receive government support, such as subsidies, to meet conservation tillage goals. Programs like the Environmental Quality Incentives Program (EQIP) and Conservation Stewardship Program (CSP) help farmers use conservation methods without financial loss. EQIP assists farmers in reducing agricultural pollution and improving soil health. CSP helps farmers plan and implement conservation efforts based on their needs.
As of 2020, about 7% of English arable land used no-till farming. The Department for Environment, Food and Rural Affairs (DEFRA) offers financial incentives, such as £73 per hectare, to encourage farmers to switch to no-till farming.
Benefits and issues
Some studies show that no-till farming can be more profitable in certain situations. It may lower costs for labor, fuel, irrigation, and machinery. No-till farming can also increase crop yields because it helps water enter and stay in the soil better, and it reduces soil erosion. In some cases, having more water in the soil means farmers can plant another crop instead of leaving the field empty.
A challenge of no-till farming is that the soil warms and dries more slowly in spring, which might delay planting. This can lead to a later harvest compared to fields that are tilled traditionally. The slower warming happens because crop residue left on the soil is lighter in color than the soil exposed during tilling, which absorbs less sunlight. However, this issue can be managed by using tools called row cleaners on planting equipment.
Another challenge is that if no-till farming does not work well for a farm, rising fuel and labor costs could make it less profitable. However, as fuel and labor prices increase, some farms might find no-till farming more practical. In spring, poor drainage in clay soil can lead to lower production if the weather is cold and wet.
The economic and environmental benefits of no-till farming may take 16 to 19 years to fully appear. In the first 10 years, farms might see lower profits. After 10 years, profits often improve.
No-till farming requires different skills than traditional farming. Farmers must use a mix of techniques, equipment, pesticides, crop rotation, fertilizers, and irrigation that work for their local area.
For some crops, like corn grown continuously without tilling, thick crop residue on the soil surface can cause problems unless the right tools and preparation are used. Specialized seed drills are needed to plant seeds through the residue. Plowing requires large tractors, but no-till farming can use smaller tractors. Farmers may save money by selling old plowing equipment, but they often keep it while trying no-till methods. This can increase equipment costs.
One purpose of tilling is to remove weeds. In no-till farming, leftover plant material from the previous season covers the soil, which can lead to more weeds or diseases compared to tilled fields. Weeds can be reduced by planting crops that grow quickly and compete with weeds, such as shrubs or trees. Herbicides like glyphosate are often used instead of tilling to prepare the soil, which means more herbicides are used than in traditional farming. Other methods to control weeds include planting cover crops in the winter, using solar heat to kill weeds, or burning them.
Herbicides are not always needed, as seen in natural farming, permaculture, and other sustainable practices.
Using cover crops to control weeds also adds organic material to the soil, which improves soil health. When using legumes as cover crops, they also add nutrients to the soil. Cover crops must be killed before planting new crops so that the new plants can get enough sunlight, water, and nutrients. This can be done with tools like rollers, crimpers, or choppers. The dead cover crops are left on the soil as mulch. Cover crops are usually killed when they start to flower.
A common problem is that nitrogen in crop residue can be tied up, making it unavailable for new plants. This can take months or years to fix, depending on the crop and the local environment. Farmers may need to use more fertilizer. One solution is to raise animals on the farm to help break down the residue. After a few years, the soil may have more organic matter, which eventually releases nutrients.
No-till farming is said to increase soil organic matter, which helps trap carbon in the soil. Many studies show that no-till farming increases soil carbon, but some studies say this depends on factors like climate and soil type. A 2020 study found that combining no-till farming with cover crops can help reduce climate change by trapping more carbon than either practice alone.
Some researchers argue that increases in carbon trapping may not always be accurate and could be due to testing errors. A 2014 study suggested that certain no-till systems might trap less carbon than traditional tilling. It also said that scientists need clearer definitions for measuring carbon in soil. The study recommended more research to understand which farming methods best trap carbon.
No-till farming can reduce emissions of nitrous oxide, a strong greenhouse gas, by 40–70%, depending on the crops grown. Nitrous oxide is 300 times more powerful than carbon dioxide and stays in the air for 120 years.
No-till farming helps soil particles stick together, which reduces erosion. Soil erosion can be reduced to levels similar to how soil naturally forms.
A study by the U.S. Department of Agriculture found that no-till farming makes soil less likely to erode than plowed soil in the Great Plains. The top layer of no-till soil has more soil particles that stick together and is two to seven times less likely to erode than plowed soil. More organic matter in this layer helps hold soil together.
According to the United Nations Food and Agriculture Organization, no-till farming can prevent desertification by keeping soil healthy and reducing erosion from wind and water.
No-till farming also reduces dust in the air because there is no plowing.
No-till farming helps soil hold more water. Crop residue allows water from rain or irrigation to soak into the soil. This residue also reduces water loss through evaporation, saving water. Tilling increases water loss by about 1/3 to 3/4 inch (0.85 to 1.9 cm) each time it is done.
In some crops, like soybeans, no-till farming can lead to gullies forming in the soil, which causes erosion. However, other crops under no-till farming show less erosion than traditional tilling. Grass waterways can help control gullies. Without tilling, gullies may get deeper each year instead of being smoothed out.
Some fields may have waterlogged soil, but switching to no-till farming can improve drainage because no-till soil allows water to enter more easily.
No-till fields often have more worms, insects, and wildlife, such as deer mice.
Tilling lowers the amount of sunlight reflected by farmland. No-till farming can increase this reflection, which might help cool the planet in a way similar to other methods of trapping