Outlook

How to Solve Soil Erosion and Improve Fertility with Contour Farming Methods

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Thomas Jefferson was a farmer who famously had a few good ideas, but part of the secret to his success was that he wasn’t afraid to occasionally borrow one as well. When he wasn’t helping to start up a new country, he lived on his 5,000-acre plantation, and one day after a devastating rain, he noticed something: a nearby farmer had avoided damage to his crops. Following practices that predated the 19th century, this neighbor had planted his rows of crops along the contour lines of the slopes in the land—perpendicular to the flow of water—rather than over them, and “his horizontal furrows arrested the water at every step till it was absorbed,” Jefferson noted.

In a letter he wrote in 1813, he described how he had subsequently adopted this style of planting, known as contour farming. “We now plough horizontally following the curvatures of the hills and hollows, on the dead level, however crooked the lines may be,” he wrote. “Every furrow thus acts as a reservoir to receive and retain the waters, all of which go to the benefit of the growing plant, instead of running off into streams.”

 

As this anecdote suggests, contour plowing is an old idea that makes all kinds of modern-day sense. The National Resources Conservation Service (NRCS) defines the practice as planting horizontal rows along slopes, forming hundreds of small dams. These obstacles slow water flow and increase infiltration, reducing soil erosion by as much as 50 percent compared to up- and downhill farming. This technique can also minimize fertilizer loss, reduce wear on equipment, and increase crop yields. And by reducing sediment and runoff, contour farming not only captures at least twice the rainwater, it improves water quality in and around the farm.

During the past two centuries, the nation and much of the rest of the planet largely drifted away from this technique in the interest of planting the most of a single crop with the least effort. But now contour farming is getting a fresh look, especially in parts of the world prone to more-extreme weather due to climate change.

 

More drops in the bucket

 

As a method for maximizing water resources, contour farming will be an increasingly important tool for growers to use while contending with a changing planet, scientists say. According to a study published in the journal Earth’s Future in April 2022, water will become scarce in 80 percent of the world’s agricultural fields by 2050 as a result of climate change.

A close-up of contour lines
A close-up of contour lines

In a letter he wrote in 1813, he described how he had subsequently adopted this style of planting, known as contour farming. “We now plough horizontally following the curvatures of the hills and hollows, on the dead level, however crooked the lines may be,” he wrote. “Every furrow thus acts as a reservoir to receive and retain the waters, all of which go to the benefit of the growing plant, instead of running off into streams.”

 

As this anecdote suggests, contour plowing is an old idea that makes all kinds of modern-day sense. The National Resources Conservation Service (NRCS) defines the practice as planting horizontal rows along slopes, forming hundreds of small dams. These obstacles slow water flow and increase infiltration, reducing soil erosion by as much as 50 percent compared to up- and downhill farming. This technique can also minimize fertilizer loss, reduce wear on equipment, and increase crop yields. And by reducing sediment and runoff, contour farming not only captures at least twice the rainwater, it improves water quality in and around the farm.

During the past two centuries, the nation and much of the rest of the planet largely drifted away from this technique in the interest of planting the most of a single crop with the least effort. But now contour farming is getting a fresh look, especially in parts of the world prone to more-extreme weather due to climate change.

 

More drops in the bucket

 

As a method for maximizing water resources, contour farming will be an increasingly important tool for growers to use while contending with a changing planet, scientists say. According to a study published in the journal Earth’s Future in April 2022, water will become scarce in 80 percent of the world’s agricultural fields by 2050 as a result of climate change.

The study’s researchers developed a new index to measure and predict water scarcity in the two major sources for farmers—rivers and rain—and noted that in the last century, demand for water worldwide has grown twice as fast as the human population. Xingcai Liu, an associate professor at the Institute of Geographic Sciences and Natural Resources Research of the Chinese Academy of Sciences and lead author of the study, says the research shows that due to growing demand and drier conditions in many parts of the world, “agricultural production is faced with unprecedented challenges.” The study says that preventing runoff and evaporation by using cover crops and practicing contour farming, among other methods, will become increasingly important.

As an agronomist and certified resource management planner, Bobby Whitescarver has seen firsthand the difference contour farming can make. During his time working in the NRCS (then the Soil Conservation Service) in the 1980s and ’90s, he helped lay out contour strips on thousands of acres in Virginia’s Shenandoah Valley, an area that’s highly prone to soil erosion. He helped a farmer build a contoured system that eliminated most of the erosion, only to see the land sold to another grower who just wanted to plant one crop and do away with the more time-consuming, soil-saving effort, Whitescarver says. The farmer now has twice the soil erosion than the amount agronomists know to be sustainable.

 

Whitescarver has seen this happen on a broader scale—the forsaking of long-term gains for short-term profits—to the environment’s detriment. “If you have annual crops, like corn, wheat, soybeans,” he says, “and you don’t have enough conservation practices on that field, and you get a rain event? All your soil and all the stuff you bought—all the fertilizer or pesticides—are all washed out. You know, how much insurance do you want to buy?”

 

A few things to know

 

Contour farming isn’t for everyone. Experts say it works best on slopes with gradients between 2 and 10 percent and in areas that receive substantial rainfall. Mountainous regions tend to be ideal.

Field in drought
Field in drought

The study’s researchers developed a new index to measure and predict water scarcity in the two major sources for farmers—rivers and rain—and noted that in the last century, demand for water worldwide has grown twice as fast as the human population. Xingcai Liu, an associate professor at the Institute of Geographic Sciences and Natural Resources Research of the Chinese Academy of Sciences and lead author of the study, says the research shows that due to growing demand and drier conditions in many parts of the world, “agricultural production is faced with unprecedented challenges.” The study says that preventing runoff and evaporation by using cover crops and practicing contour farming, among other methods, will become increasingly important.

As an agronomist and certified resource management planner, Bobby Whitescarver has seen firsthand the difference contour farming can make. During his time working in the NRCS (then the Soil Conservation Service) in the 1980s and ’90s, he helped lay out contour strips on thousands of acres in Virginia’s Shenandoah Valley, an area that’s highly prone to soil erosion. He helped a farmer build a contoured system that eliminated most of the erosion, only to see the land sold to another grower who just wanted to plant one crop and do away with the more time-consuming, soil-saving effort, Whitescarver says. The farmer now has twice the soil erosion than the amount agronomists know to be sustainable.

 

Whitescarver has seen this happen on a broader scale—the forsaking of long-term gains for short-term profits—to the environment’s detriment. “If you have annual crops, like corn, wheat, soybeans,” he says, “and you don’t have enough conservation practices on that field, and you get a rain event? All your soil and all the stuff you bought—all the fertilizer or pesticides—are all washed out. You know, how much insurance do you want to buy?”

 

A few things to know

 

Contour farming isn’t for everyone. Experts say it works best on slopes with gradients between 2 and 10 percent and in areas that receive substantial rainfall. Mountainous regions tend to be ideal.

For those who work such land, the first step toward adopting this practice is drawing contour lines, which the NRCS or a local cooperative can help accomplish. Farmers will then need to plant some cover crops or vegetative barriers in strips or rows around their slopes and protect the soil with mulching. They can then place tree trimmings or plant residue in strips around the slope to help catch and contain water. Planners also recommend installing hillside ditches along the incline with some simple hill forming, which will shorten the slope and redirect water in a way that makes it more easily absorbed.

 

The practice is regaining momentum worldwide. Farmer field schools in some of the most impoverished areas of Jamaica are offering lessons in contour farming for farmers who work on steep hillside plots that see both drought and flooding. In parts of East Africa, the International Crops Research Institute for the Semi-Arid Tropics ran a pilot contour-farming program that included more than 2,500 farmers across two study sites; the practice reduced soil loss by 163 percent and increased income for 78 percent of the farmers.

 

For farmers, the changing climate and evolving supplies of land and water are making an already challenging vocation still more complex—even as their contributions to a hungry world have become increasingly important. Growers working in certain regions with particular types of land might find contour farming to be not only a valuable tool for growing more profitably and efficiently but also one that could help save the world.

 

SOURCES

 

https://news.agu.org/press-release/water-scarcity-predicted-to-worsen-in-more-than-80-of-croplands-globally-this-century/

https://earthsky.org/earth/water-scarcity-80-percent-croplands-farming-method/

https://farmingfirst.org/2019/09/the-first-step-towards-climate-smart-agriculture-get-information/

https://www.nrcs.usda.gov/wps/portal/nrcs/detail/null/?cid=nrcseprd414214

https://www.eurekalert.org/news-releases/951856

https://rocketskills.in/blog/contour-farming-everything-you-should-know-about-this-unique-farming-technique/

https://www.gettingmoreontheground.com/2016/07/26/contour-farming-increases-soil-moisture/

https://africa-rising.net/how-contour-bunding-and-other-technologies-can-reduce-soil-erosion-and-raise-productivity-in-african-watersheds/

Contour line map
Contour line map

For those who work such land, the first step toward adopting this practice is drawing contour lines, which the NRCS or a local cooperative can help accomplish. Farmers will then need to plant some cover crops or vegetative barriers in strips or rows around their slopes and protect the soil with mulching. They can then place tree trimmings or plant residue in strips around the slope to help catch and contain water. Planners also recommend installing hillside ditches along the incline with some simple hill forming, which will shorten the slope and redirect water in a way that makes it more easily absorbed.

 

The practice is regaining momentum worldwide. Farmer field schools in some of the most impoverished areas of Jamaica are offering lessons in contour farming for farmers who work on steep hillside plots that see both drought and flooding. In parts of East Africa, the International Crops Research Institute for the Semi-Arid Tropics ran a pilot contour-farming program that included more than 2,500 farmers across two study sites; the practice reduced soil loss by 163 percent and increased income for 78 percent of the farmers.

 

For farmers, the changing climate and evolving supplies of land and water are making an already challenging vocation still more complex—even as their contributions to a hungry world have become increasingly important. Growers working in certain regions with particular types of land might find contour farming to be not only a valuable tool for growing more profitably and efficiently but also one that could help save the world.

 

SOURCES

 

https://news.agu.org/press-release/water-scarcity-predicted-to-worsen-in-more-than-80-of-croplands-globally-this-century/

https://earthsky.org/earth/water-scarcity-80-percent-croplands-farming-method/

https://farmingfirst.org/2019/09/the-first-step-towards-climate-smart-agriculture-get-information/

https://www.nrcs.usda.gov/wps/portal/nrcs/detail/null/?cid=nrcseprd414214

https://www.eurekalert.org/news-releases/951856

https://rocketskills.in/blog/contour-farming-everything-you-should-know-about-this-unique-farming-technique/

https://www.gettingmoreontheground.com/2016/07/26/contour-farming-increases-soil-moisture/

https://africa-rising.net/how-contour-bunding-and-other-technologies-can-reduce-soil-erosion-and-raise-productivity-in-african-watersheds/