By Alice LeBlanc for NWNL
(Edited by Alison Jones, NWNL Director)
This is the second blog in a NWNL series on how soil impacts water quality and availability. Alice LeBlanc is an economist and independent consultant who lives in NYC. For more than 25 years, she has worked in both corporate and NGO settings to promote market-based and land-use sector solutions to the problem of climate change.
PAYING ATTENTION TO SOIL
Soil has an indisputably important role in producing much of the food we eat and supporting trees and vegetation that provide wood, fiber, habitat, natural beauty and other ecological services. However, the direct relationship between healthy soil and clean, plentiful water is perhaps less known. Often overlooked is the role healthy soils play in ameliorating environmental problems that include water pollution, water scarcity and climate change.
Conventional agriculture uses inorganic fertilizers and pesticides, aggressive tillage, heavy machinery and wasteful irrigation. These practices often degrade soils by their reduction of soil carbon and compaction. Resulting erosion and chemical run-off pollutes waterways and groundwater. Further, their greenhouse gas emissions become significant contributors to climate change. Although increasing and stabilizing food production, modern agricultural practices hurt our soil and water – two of the most basic elements essential to life on earth,
“Climate Smart Agriculture” (CSA) is a current buzzword of hope among environmentally-conscious agricultural experts, especially in developing countries. CSA combines cost-effective practices to increase soil health and crop productivity, use water more efficiently, decrease the use of inorganic fertilizers, and reduce or even sequester CO2 and other greenhouse gases. CSA practices include low-tillage or no-tillage of soils; contour tillage; drip irrigation; terracing of sloping fields; and organic or custom-made (precision) fertilizer. Last in this list is biochar – a substance used successfully centuries ago by Amazon farmers.
Kilns used for making biochar
Biochar is created by applying high heat to biomass (e.g. crop residues, otherwise burned or left to decay in the atmosphere) in enclosed, oxygen-free spaces. This process, called pryolysis, differs from burning as it doesn’t use oxygen; produce combustion; or emit CO2. Biochar can be produced anywhere inexpensively on a small scale by subsistence farmers with cook stoves or kilns, using on-hand materials. It can also be produced on medium and larger commercial scales.
When used as a soil amendment, biochar alters the soil’s property, allowing it to retain more water and nutrients and enable some plants to more efficiently “fix” atmospheric nitrogen, thus attracting more microbes. This improves plant growth and resilience. Biochar’s effect is described as creating “microbe hotels” which draw microorganisms and bring additional carbon into the soil. To be most effective in increasing plant productivity, biochar can be mixed with organic fertilizer such as manure and ground animal bones.
Biochar production area
For the past year or so, I have been helping lay the foundation for the African Holistic Ecosystem Regeneration Initiative–HERI (a Swahili word for happiness). HERI aims to scale up regenerative and climate smart agriculture, as well as better grazing practices across Africa. Our emphasis is specifically on smart use of biomass and nutrients, including using biochar as a soil amendment and planting of soil-enhancing trees with high-value crops, such as palm oil, coffee, cacao, shea butter, cashews and moringa. This undertaking is being led by the International Biochar Initiative (IBI), the leading non-profit dedicated to the promotion of biochar research and commercialization.
The agricultural benefits of biochar as a soil amendment include increased food security and crop productivity, greenhouse gas reductions, increased resilience to climate change impacts, and poverty alleviation.
Many African soils are losing soil’s organic matter at dramatic rates, which has degraded soil fertility to an extent that threatens livelihoods of subsistence farmers in entire regions. Biochar combined with organic fertilizer has been demonstrated in many small pilot projects in Africa and around the world to significantly increase soil productivity; retain more water; and sequester carbon, especially in highly weathered tropical soil.
Milkiyas Ahmed, Lecturer, Jimma University, College of Agriculture, holding crop residue to be turned into biochar
While results vary depending on materials used to make the biochar, soil and crop type, fertilizer materials and climatic conditions, biochar increases productivity on average by 25% in tropical regions – and up to 80% if nutrient-rich feedstocks are used to make the biochar. If the soil is of extremely poor quality to begin with, productivity increase due to biochar can be significantly greater, yielding 100% to 500% increases.
Another benefit is improved soil fertility when biochar use, combined with planting perennial tree crops, pulls more CO2 out of the air. That carbon is then stored in increased amounts in above-ground biomass and root systems. Those trees’ root systems then further contribute to soil health. Additionally, the ability to sell perennial crops with higher yields, gained when using biochar and natural fertilizer, will generate higher revenues.
Bins used to compost biochar with different fertilizer materials
Biochar systems, when properly designed, aregreenhouse-gas neutral. They even become greenhouse-gas negative when they sequester carbon in woody biomass, roots and soils, and more microbes increase soil carbon. As well, heat or combustible gases can be recovered from the biochar production process to generate usable renewable energy or electricity. In Africa, biochar produced with individual “cook stoves” has been used to generate heat as a clean, renewable energy for cooking. When biochar is produced on a larger scale in big machines, a combustible, renewable gas can be fed into an electric generator to serve a micro-grid. Energy production from biochar production in some cases in Africa could generate revenues.
As well as direct benefits to agricultural production, biochar combined with agroforestry can improve water use efficiency; protect watersheds, water quality and water quantity; and decrease deforestation pressures.Without these measures, the outlook for subsistence farmers and food security in Africa is grim, especially in the face of increasing duration and frequency of droughts due to climate change and explosive African population growth.
Plots for testing the impact of different biochar plus fertilizer combinations
IN THE FIELD
On a recent trip to Ethiopia, I visited a biochar pilot project conducted at the University of Jimma in collaboration with Cornell University. The project is evaluating the effectiveness of different formulas for co-composting biochar with natural fertilizers. This work is being done in tandem with several dozen farmers incorporating biochar in their fields.
Jimma is on the Awetu River about 150 miles southwest of Addis Ababa, not far from the lakes of the Great Rift Valley. It was my first visit to sub-Saharan Africa and my first visit to fields of small farmers there. Milkiyas Ahmed, a faculty member at the Agricultural College, gave me a tour of the biochar production machines. I saw vats where the biochar co-composting is done, and plots where different crops are grown, with and without the biochar amendment. In the trees around the experimental plots, black-and-white monkeys eyed the tender young plants. A guard stood ready to scare them off if necessary.
A farmer in the village who has seen gains from biochar
We walked through the village of farmers with whom Milkiyas worked. We visited fields of the farmer who set the highest bar for producing and using the biochar. His method for making biochar in a hole in the ground was a very low-cost method indeed. The multi-cropped fields, containing a variety of perennial trees, enhanced a beautiful landscape. There were two young boys swimming in a stream that ran through the fields on that warm Sunday afternoon. One could only hope and expect that the water quality was safe and swimmable — which it could be with the right set of agricultural practices.
All photos © Alice LeBlanc.