Saving Soil

Saving Soil
Rattan Lal will guide a new effort to restore soils across Latin America and the Caribbean

Story by Alayna DeMartini

Tourists traveling through Central and South America or the Caribbean might easily miss, amid the beauty of the tropical landscape, the degraded soil.

That soil affects livelihoods. In one of the largest food-producing regions of the world, 36 million people suffer from malnutrition. A third of the soil is moderately to highly degraded, driving down crop yields and income.

An initiative has just been launched across South and Central America and the Caribbean to enrich depleted fields there so they can better produce food, counter the effects of climate change, and reduce poverty, which affects nearly half the total population.

In South and Central America as well as the Caribbean, one-third of the soil is moderately to highly degraded.

“The most degraded soils have not reached the point of no return. They can still be restored,” said Rattan Lal,a renowned soil scientist and Distinguished University Professor at The Ohio State University College of Food, Agricultural, and Environmental Sciences (CFAES). 

Lal has just been named the scientific advisor to the new Living Soils of the Americas initiative involving 34 countries across the western hemisphere to transform agriculture and improve the health of the soil. 

Using techniques Lal has promoted over five decades throughout the world, he will train staff from countries in the region and advise them on measures to enrich the soil and on how to monitor progress toward increasing the amount of carbon in the soil. Organic carbon is a key ingredient determining the soil’s ability to grow crops. 

In many fields in Central and South America and the Caribbean, organic carbon has dwindled to about a quarter of the amount needed to grow healthy crops, Lal said. Not only have crop yields declined by 10% to 30%, the crops harvested contain fewer nutrients essential for human health. And more fertilizers, water, and energy are being used to try to grow as much as possible on those depleted fields.

“The region continues to be one of the world’s largest food exporters. But that’s been achieved by dumping a lot of chemicals on the land, and by using a lot of irrigation and energy. ”Rattan Lal

“The region continues to be one of the world’s largest food exporters. But that’s been achieved by dumping a lot of chemicals on the land, and by using a lot of irrigation and energy,” he said. 

The soil too is suffering from the effects of climate change. Higher temperatures and more droughts have decimated the amount of water in the soil. In coastal areas, as sea levels rise, low-lying areas have flooded with saltwater, and excess salts accumulate in the soil, hindering crop growth. At the same time, agriculture is contributing to climate change as the primary source of carbon dioxide and other greenhouse gases in the region.

But nutrient-rich soil can help counter that, Lal said. Healthy plants can best take up carbon dioxide in the air during photosynthesis, convert that gas into oxygen, and return carbon to the soil when the plant decomposes. As a result, plants can act as a buffer against rising levels of carbon dioxide in the air. However, if fields are left barren, and forests cut down, fewer plants can take up that carbon dioxide.

In 2018, Lal worked in a drought-prone region of Chile to improve the soil’s ability to take up and hold onto water.

“Many of the current farming practices only take away nutrients from the soil,” Lal said. “They don’t return those nutrients, so they have to use a whole lot more artificial fertilizers, pesticides, and irrigation, all of which are symptoms of the problem.” 

In his efforts to help restore the soil, Lal will be advising against cutting down swaths of trees to create farmland and tilling the soil. Whenever soil is disturbed through tilling, some carbon within that soil leaves, entering the air as carbon dioxide. He also will advocate planting cover crops when the land is not being used to raise a cash crop. A cover crop can prevent a field from eroding and keep the microorganisms in the soil active. 

“If we can change the mindset of the 20 million small landholders as well as policymakers and have them adopt these practices, we can eliminate hunger and malnutrition in the region and we can protect the natural resources that are now being degraded,” Lal said. 

Bringing up the amount of carbon in the soil to an optimum level likely will take one to two decades, he said.

“It’s a very slow process, but you have to begin somewhere,” Lal said. “Using these practices, we will see improvement. There is no way we can go further down.” 

“Using these practices, we will see improvement. There is no way we can go further down.”Rattan Lal

Within three to five years, some results will be evident, said Manuel Otero, general director of the Inter-American Institute for Cooperation on Agriculture (IICA), which represents the 34 countries involved in the soil initiative. 

More carbon dioxide will be taken in by healthy plants and returned to the soil, the soil will become more fertile and able to retain water, and fertilizers and seeds will become more effective, Otero said. 

“While soil degradation can occur very rapidly, restoring soil health is not a short-term endeavor, though it is one that needs to start immediately,” he said. “Without healthy soils, it’s impossible to think about anything else.”