Healthier Soil Means Healthier People

To secure the world’s food supply and feed the hungry, feed the land first


October 2016 winner
Food security in a changing climate
Kendall Morgan
Ecohydrology & Hydrobiology
, Volume 13, April 2013, Pages 8-21

Read the story about the award-winning research

More than 10 million children under five living in developing countries around the world die each year due to hunger-related causes. Millions more suffer from chronic hunger or malnutrition. Looking to the future, the demand for food will only grow as the world’s population is expected to reach 9.7 billion by the year 2050. The challenges to food security can seem almost insurmountable. But according to a paper awarded the Elsevier Atlas Award in November 2016, solutions and reasons for hope can be found by remembering to keep the land fed first.

In the research article published in the journal Ecohydrology & Hydrobiology in April 2013, Rattan Lal of The Ohio State University’s Carbon Management and Sequestration Center says that food security in a changing climate can be achieved in part by adopting basic principles of ecohydrology, an interdisciplinary field focused on the interaction between water and ecosystems. As a first step, Lal calls on policymakers, farmers, and the general public to recognize that the health of people depends on the health of the land and soil.

“The health of soil, plants, animals, people, and ecosystems is one and indivisible,” Lal said. “Healthier soil creates healthier people. That’s especially true for micronutrient deficiency. If the soil is deficient, then the plants grown in it are deficient and the food consumed by people is deficient. Therefore landscape management for conserving and sustaining soil resources is essential.”

Improving the health of soil means ending practices that strip from the land and give nothing back. When the organic content of soil falls below 2 percent, as it does in parts of South Asia and Sub-Saharan Africa, the land acts like a sieve. Water and nutrients percolate right through to become unavailable to plants, including agricultural crops.

“My philosophy is that grains are for people and crop residue is for the land,” Lal says. Organic soil amendments are also key, including composted manure and other biological waste.

Soil that’s properly cared for comes with other advantages. For example, organic matter in the soil acts like a sponge, holding more “green water,” which is available to plants. When soil is able to retain moisture, agricultural lands become more resistant to periods of drought.

Of course, it’s not easy for poor farmers to leave crop residues or manure for the land. That’s because farmers in many countries often depend on crop residues to feed their animals. Manure is also burned as a source for heat and cooking fuel.

There are also new and emerging threats to soil health, including rapid urbanization, risks of land degradation because of climate change and extreme events, and growing interest and demand for non-agricultural uses of crop residues (e.g., cellulosic ethanol), which presents new incentives to take organic carbon from the land. Ultimately, it’s clear that the success of efforts to improve soil health will depend on policies that recognize the value of land and water resources and create incentives for farmers to change their practices.

“If we do not compensate farmers, then we are undervaluing this precious resource,” Lal said. “Undervaluing resources leads to the tragedy of the commons and it is this tragedy we see, especially in places like Sub-Saharan Africa, South Asia, and Haiti where organic carbon has been mined by extractive farming.”

So what can members of the general public do to make a difference in their own lives? Lal recommends reducing food waste in their homes and communities, composting, and considering a plant-based diet. After all, it takes eight to ten kilograms of grain to produce one kilogram of red meat.

A Conversation with Rattan Lal

There are many millions of hungry people in the world today and tremendous challenges to global food security as the world’s population continues to grow and the climate shifts. In this podcast, Rattan Lal of The Ohio State University speaks about these challenges and how concepts of ecohydrology can help.

Atlas: People, all over the world, are going hungry, sometimes even in developed countries. Can you help us put these challenges into perspective as we look ahead to the future?

Rattan Lal: About 800 million people, distributed mostly in developing countries, are going hungry, according to the latest estimates. Twenty-five percent of them are in South Asia. Another one in four are in Sub-Saharan Africa. But you are right, there are hunger prone people including in the U.S. I think statistics show one in seven in the U.S. are prone to chronic hunger, which means they are getting less than 2300 calories per day. In addition to that, two billion people around the world are prone to malnutrition. They have a deficiency of protein, micronutrients, and other substances essential to health.

Atlas: How can soil health be improved?

Rattan Lal: Soil is a living entity. A spoonful of soil contains millions and millions of microorganisms. Healthy soil has a lot of micro- and macro-organisms. These cannot survive without food and their food is soil organic matter. Generally speaking, soil health is good if the amount of organic matter is about 3.5 percent (2% carbon equivalent) in temperate regions. If organic matter decreases below that strongly, soil health is adversely impacted. For example, in Sub-Saharan Africa, the organic carbon content in some cropland soil is less than 0.1 percent. In South Asia—including Pakistan, India, and Bangladesh—soil organic carbon content in cropland can be less than 0.05 percent. When organic matter is depleted so much and farmers apply fertilizer and irrigation, the soil performs like a sand culture. It has no ability to hold nutrients and chemicals are easily washed into the ground and stream water, causing problems for water quality and the health of the people concerned. For these reasons and others, it’s important to take steps to improve soil organic carbon content in depleted soils to a level above 1.5 or 2.0 percent.

Atlas: In practical terms, how would you go about increasing organic content in soils?

Rattan Lal: The idea is to create a positive soil carbon budget. Soil is like a bank account: You must put more into the bank account than you withdraw for the balance to increase. Carbon is withdrawn from soil in many ways, through erosion by water and wind, which can be worsened by plowing. As world temperatures increase, microbes eat more to deplete organic matter more rapidly. Another issue is extractive farming. In extractive farming, farmers take away everything from the land. They take the grain, of course, but also crop residues and nothing is left to the land. Especially in poor countries, farmers take away everything. Crop residue is taken to feed cattle and cattle dung is not used as manure or compost. It is burned as cooking fuel, so nothing is returned to the land. Poor farming is really a burden on the land. The poverty, hunger, misery and desperation of people are transferred to the poverty and sickness of the land. This is a vicious cycle as hungry and poor people pass their suffering on to the land. It’s a vicious cycle from which it’s very difficult to get out.

Atlas: What are the costs of encouraging soil health? How can farmers be incentivized to do this?

Rattan Lal: If you want to increase carbon, then you need to leave more crop residues and manure for the land along with additional micronutrients. Somebody has to pay the price of these residues to make sure farmers invest in the land. The societal value of carbon is estimated at $120 per ton of carbon. It comes to about $16 per acre per year in terms of the cost of net carbon sequestration with good management practices. The question is: are we willing to pay the farming community that much? Usually, the answer is no. But this is not a subsidy; it is an ecosystem provision by the farmer for the global community.

Atlas: We’ve been talking a lot about soil and carbon. In your article, you also write about green water. What is green water and how can we improve or increase the amount of green water?

Rattan Lal: Soil is one part. Water and nutrients is another part. Green water is the amount of water in soil that plants actually absorb and transpire. Soil organic matter is like a sponge that holds water in soil so it cannot be leached down into ground water.The amount of water held in the soil and that which plant roots can absorb is essential to reducing the impacts of drought during the crop growth. More organic matter means more water retention and more water available to plants. Organic matter also influences the resistance of soil against heat wave that exacerbates the drought. You need more organic matter to improve the supply of green water. This is what we call climate-smart agricultural soil.

Atlas: What other practical steps can people take?

Rattan Lal: There is no one panacea. There are many steps that can be taken including no plowing, leaving crop residues on the land as in conservation agriculture, growing cover crops in the off-season. Trees can be grown in association with crops. Cattle can be integrated into production by growing forage crops and bringing manure back onto the land. A significant amount of chemical fertilizer can be replaced by manure, recycled biowaste, rhizobium inoculation, and mycorrhizal fungi . Another concept is biochar, in which trees and shrubs are grown on agriculturally marginal land then harvested and burned at high temperatures under low oxygen conditions to produce energy and charcoal that can be applied to the land as an amendment. Drip irrigation and harvesting of rainwater can help. There are many practices like this and they will vary from place to place. The key is adapting these basic principles according to site-specific conditions and promoting their adoption. To do this in poor countries and even in the U.S., some incentives are needed.

Atlas: How optimistic are you that we can start to move in this direction?

Rattan Lal: I’m very optimistic. Policymakers are now talking about making agriculture a solution to the problem. Think about this. We’ve been talking about agriculture as a problem child. We have to make agriculture a solution. It is agriculture that’s going to feed the world. Also, when we say 800 million people need another billion tons of cereal grains, I don’t think so. We have more than enough land right now. We have more than enough food. Now what should we do? We need to minimize food waste. In each country, whether developed or developing, 30 to 50 percent of food is wasted. It’s produced and never consumed. It’s wasted in the field or the store or ordered in a restaurant but not eaten and taken to a landfill. That waste must be stopped. In India, there’s a bumper harvest of wheat and rice and almost three to five million tons of it rot in the field because there’s no place to store them. India is not the only place where that happens. Food is also discarded for reasons of physical appearance rather than quality. So food waste has to be stopped. Each of us must take personal responsibility. We must not take food and soil for granted. They are very precious resources, so we must contribute through our own incremental improvements in lifestyle. We also have to promote a plant-based diet. It won’t happen over night, especially in the U.S., Canada and Europe. We need to understand that it takes eight to ten kilograms of grains to produce one kilogram of red meat. An excessive use of animal-based diet is not healthy.

Right now, the land area for cereal production, including rice, wheat, corn, and sorghum, is 720 million hectares. We don’t need that much land. We can double or  triple production per unit of land in South Asia , Sub-Saharan Africa and the Caribbean with sustainable intensification of agroecosystems. It means producing more food per unit of land area, more food per unit of pesticide, more food per unit of energy, more food per unit of greenhouse gas emission. We know already how to do it; it’s a matter of promoting adoption of improved systems of soil management among farmers and policy makers. I don’t think there’s a shortage of food. The problem is distribution and also political crises. That’s why people are starving. So peace and stability, fairness, democratic principles—these are all very important.


Rattan Lal (The Ohio State University)

Hunger (United National World Food Programme)

Soil Health (USDA)

Ecohydrology & Hydrobiology



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