Posts Tagged ‘soil fertility’

Apr07

William Albrecht: Unhealthy Soil, Unhealthy People

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By Jenny Beth Dyess

William Albrecht (1888–1974) cared about the link between soil health and people’s health. As he witnessed the rise of industrial agriculture, he became deeply concerned about the negative impacts of profit driven farming on the soil. Chairman of the Department of Soils at the University of Missouri in the 1950s, Albrecht desired, as a scientist, to understand the complexities of soil health and how that might impact humans.

William Albrecht was fascinated by the link between soil fertility and public health. (Photo credit: Bernard Pollack)

Fascinated by the link between the health of people and the soil, he reviewed the dental records of 70,000 U.S. sailors from the World War II era. Using cavities as indicators, he found that nutritional deficiencies, particularly in calcium and potassium, in the sailors’ dental health records correlated with insufficient fertility of the soil in the region of the U.S. they were from. For example, someone from the more weathered and nutrient deficient lands east of the Mississippi River had more cavities than someone from Hereford, Texas where soil nutrition was significantly higher.

While dental hygiene has drastically improved American teeth there are other health problems which may still be linked to the soil. In 2003, Surgeon General Richard H. Carmona stated that nearly two out of every three children are overweight or obese. Currently, 33.8 percent of American adults are obese, according to the Centers for Disease Control and Prevention, and numbers are on the rise. In 2000 no state had an obesity rate of 30 percent or more but by 2009, 9 states had obesity rates of 30 percent or more and in 2010 that number had risen to 12 states.

Compared with the early 1900s, not only has food per capita available to Americans increased, Americans are eating more nutrient dense foods. Meat consumption has quadrupled and cheese consumption is seven and a half times what it was in the early 1900s, but fresh fruit and home grown vegetable consumption have decreased. In 1919, about 25 percent of vegetables consumed were from a home garden, by 1998 that had dropped to less than 3 percent.

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Posted by Nourishing the Planet in Agriculture, Farmers, Fertilizer, Health, organic, Soil

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Nov22

Five Innovations that are Boosting Soil Fertility

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By Joseph Zaleski

Crops need air, sun, water, and soil to thrive. When it comes to soil, however, quality usually trumps quantity. Rich and fertile land boasts a healthy mixture of phosphorous, potassium, and nitrogen, along with water, air, and soil micro-organisms that break down organic matter.

But what happens when these elemental building blocks are disrupted? The Green Revolution of the mid-20th century implemented a variety of practices, including the widespread use of pesticides and fertilizers. Yet, improperly applying the Green Revolution’s principles can sometimes do more harm than good. Overfertilizing and destructive land use practices, including deforestation, can deplete vital nutrients in soil, and no amount of inorganic fertilizer can replace fundamental topsoil. In addition, higher annual temperatures, more extreme weather events and persistent droughts, and increasing population are also exhausting the land. These conditions are creating a cycle of soil degeneration which is stunting agricultural yields and presenting farmers with a new crop of concerns.

Today, Nourishing the Planet provides five methods that farmers and scientists are using to combat rising soil infertility.

Soil is an ecosystem unto itself. It’s what we don’t see underground that makes or breaks a harvest. (Photo credit: Bernard Pollack)

1. Cover Cropping / Green Manure: In our State of the World 2011 report, agroecologist and author Roland Bunch defines cover crops / green manure as “any plant, whether a tree, bush, or vine, that is used by a farmer to…improve soil fertility or control weeds.” In practice, cover crops are planted alongside or interspersed with other crops to cut soil-eroding wind, prevent overexposure to the sun, and stimulate a healthy soil system. Just as farmers will turn to manure to bolster the soil, they can also clip and spread cover crops’ leaves as organic green manure.

Cover Cropping / Green Manure in Action: According to Roland Bunch, there are more than a million farmers now actively using cover crops / green manure worldwide. In Africa alone, there are over 120 plant species that are being used or could be used for this purpose. One promising example is the cowpea (also known as the black-eyed pea). This legume is both a nitrogen-fixer, which means that it takes nitrogen from the air and replenishes it in the soil, and deeply rooted, which makes it resistant to drought. Furthermore, the cowpea itself is a nutritious staple food for both people and animals.

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Posted by Nourishing the Planet in Agriculture, Fertilizer, Livestock, Permaculture, Soil, Waste, Water

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Nov15

What Works: Producing Food from Waste

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By Kim Kido

In sub-Saharan Africa where nearly a third of the population is hungry, over a quarter of food produced is lost to spoilage. And the hundreds of millions of livestock on the continent are responsible for degrading almost half of crop land on the continent, which makes up over one-third of overgrazed lands worldwide. But the uneaten food, manure, and other forms of waste are being used by farmers to produce fertilizer, fuel, and food.

Decorated compost piles in Malawi (Photo credit: Scott Gregory)

South Africa has been diverting organic matter from its landfills since 1969. About 2 percent of waste generated in Cape Town, and 15 percent in Johannesburg, is diverted through composting. In Johannesburg, compost sales were projected to completely offset production costs by 2006. Two other municipalities operate smaller scale composting facilities in the country. A project funded by the World Bank in Uganda has nine municipalities establishing composting plants.

Composting food waste relieves pressure on landfills while producing an inexpensive, nutrient-rich soil amendment that farmers use to improve soil fertility. Compost adds organic matter to the soil, increasing the water-holding capacity of its structure, facilitating root penetration, and making nutrients available to crops over time.

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Posted by Nourishing the Planet in Agriculture, Compost, Farmers, Fish, Fuel, Livestock, Soil, Waste

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Jun14

What Works: Farming with trees

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By Kim Kido

This post is part of a series where Nourishing the Planet asks its readers: What works? Every week we’ll ask the question and every week you can join the conversation!

Poor soils, lack of irrigation, and limited access to inputs, including fertilizer, are some of the barriers farmers face to increasing food production, and alleviating food insecurity, in sub-Saharan Africa.  Incorporating trees on farms can help increase yields by building soil fertility, reducing erosion, retaining water, or providing shade. And many species produce high-value fruits, timber, fodder, or medicine that can be sold or used to meet household needs. Ecosystem benefits like habitat creation and carbon sequestration are added benefits.

Trees on a farm in Kenya. (Photo credit: International Center for Tropical Agriculture (CIAT))

Planting nitrogen-fixing leguminous tree species, like Faidherbia or Acacia albida, in maize fields has helped achieve up to four-fold yield increases in Malawi, Zambia, Tanzania, and Ethiopia. During the rainy season, when crops are planted, the Faidherbia acacia loses its nitrogen-rich leaves as it enters dormancy. Crops are provided with a source of nitrogen, and the tree’s bare branches don’t block sunlight. And when the availability of fodder is limited in the dry season, the trees produce seed pods that livestock can eat.

While legumes improve soil fertility, planting fruit trees amongst other crops can provide emergency income and a source of food in times of scarcity. For small farmers like Virginia Wangui Njunge, who farms two acres north of Nairobi in Kenya, planting fruit trees is a way to minimize risk by increasing productivity and crop diversity. Njunge sells avocados, guavas, apples, and mangos from her trees that grow along with vegetable crops, including tomato and cabbage. Intercropping fruit trees with annual and indigenous vegetable crops to provide food and income while trees mature is a common practice in Kenya.

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Posted by Nourishing the Planet in Africa, Agriculture, agroforestry, Climate Change, Erosion, Soil, Trees, Water

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Feb25

Fighting Climate Change by Managing Livestock

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By Mara Schechter

In the United States, grass-fed beef producers could reduce their annual greenhouse gas (GHG) emissions by 87.5 percent, according to a recent report by the Union of Concerned Scientists (UCS). Raising the Steaks: Global Warming and Pasture-Raised Beef Production in the United States finds that farmers raising beef entirely on pasture—where all beef cattle spend the first months of their lives—can help mitigate climate change. And the report’s findings may have even greater implications for other countries.

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In adopting better management practices, farmers across the world could help fight climate change while increasing the health of their soil. (Photo credit: Bernard Pollack)

“Livestock contribute a greater share of global warming emissions in parts of the world with lower industrial emissions,” writes Doug Gurian-Sherman, UCS Senior Scientist and author of the report. And meat production is growing fastest in the developing world, where smallholder farmers and degraded soils could both benefit from the report’s suggested management practices, including avoiding the overuse of fertilizer and preventing overgrazing to increase soil health and carbon sequestration.

The U.S. beef cattle industry produces 160 million metric tons of GHGs each year. But better management practices could reduce emissions by as much as 140 million metric tons—the equivalent of taking 21 million trucks and cars off the road.  One practice the report highlights is planting legumes in pastures.

One legume seems especially promising— birdsfoot trefoil. Birdsfoot trefoil, a yellow plant that looks like some varieties of clover, produces special compounds which beef cattle digest more efficiently than other types of feed. Cattle are flatulent, burping and passing gas as they eat. And because cattle are ruminants, with four stomachs, they produce methane, a GHG that is 23 times more potent than CO2. But when cattle eat birdsfoot trefoil, they digest it differently than other grasses or grain, and produce less methane. (more…)

Posted by Danielle Nierenberg in Africa, Agriculture, Climate Change, Food, Food Security, Hunger, Income, Livestock, Nourishing the Planet

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