ECHOcommunity Conversations

Mitigating climate change

Carbon management in dryland agricultural systems.

Dryland areas cover about 41 % of the Earth’s surface and sustain over 2 billion inhabitants.
Soil carbon © in dryland areas is of crucial importance to maintain soil quality and productivity and a range of ecosystem services.
Soil mismanagement has led to a significant loss of carbon in these areas, which in many of them entailed several land degradation processes such as soil erosion, reduction in crop productivity, lower soil water holding capacity, a decline in soil biodiversity, and, ultimately, desertification, hunger and poverty in developing countries.
As a consequence, in dryland areas proper management practices and land use policies need to be implemented to increase the amount of C sequestered in the soil.
When properly managed, dryland soils have a great potential to sequester carbon if financial incentives for implementation are provided.
Dryland soils contain the largest pool of inorganic C.
However, contrasting results are found in the literature on the magnitude of inorganic C sequestration under different management regimes.
The rise of atmospheric carbon dioxide (CO2) levels will greatly affect dryland soils, since the positive effect of CO2 on crop productivity will be offset by a decrease of precipitation, thus increasing the susceptibility to soil erosion and crop failure.
In dryland agriculture, any removal of crop residues implies a loss of soil organic carbon (SOC).

Therefore, the adoption of **no-tillage practices in field crops and growing cover crops in tree crops have a great potential in dryland areas due to the associated benefits of maintaining the soil surface covered by crop residues.
Up to 80 % reduction in soil erosion has been reported when using no-tillage compared with conventional tillage.
However, no-tillage must be maintained over the long term to enhance soil macroporosity and offset the emission of nitrous oxide (N2O) associated to the greater amount of water stored in the soil when no-tillage is used.

Thanks, Graham. A good piece to add to the EC collection on Climate Change and Mitigation. Are there Network observations and experiences that can contribute to the Conversation?

I am in contact with many poor farmers in SSA countries who suffer
from depleted/poisoned soil.
Many emails confirm the need for cover crops and the wonderful
results with JB (Jack beans).
But our efforts are very limited by lack of finance!

As stated below today by a helper in Zambia "our governments here in

sub-saharan Africa support commercial farmers only."
This is true and a real scandal!

      Hello Graham,  am not

sure if my first mail reached you. I had run out of space in my

  Am good and hope you Are too. It's been two weeks or so now since

you heard from me. Like i said, i had gone to do the work with
farmers, educating them on Jb and Vb.

  Though,  to my suprise,  it's almost as if our governments here in

sub-saharan Africa support commercial farmers only.

  I had to start afresh with the same group going from village to

village training farmers.

  You talk about Jb and Vb, they completely don't know about it.

Through on a positive note, they are ready to try them since they
now know the benefits of growing them. Thank God for the resource
materials, they’re of a great support to my work here.

  Some ngo's like KATC deal with many crops including Jb and Vb but

to my suprise, farmers around Lusaka are still very ignorant
about these crops, talk less of those in the remort areas like
where i had gone.

  This week am making to another visit.


This is crucial stuff, and I would add that there’s no point talking about carbon without talking about water: the clue is in the equation - CO2+H2O+Sun’s energy --> sugars + O2, so unless we deal with the water cycle all the carbon strategies in the world won’t help us. We have to get more water in the soil as well as C

We really need to train people to focus on income per hour for people and then by focusing on maximizing the income per hour by growing the highest value crops you can begin to set aside emergency money for when the weather brings in challenges to completing a successful crop production year. Irrigation is often a good investment but sometimes does not bring an adequate return on investment nor not accessible. I think low-value crops and focusing on subsistence or sustainability is one of our problems because we set the goal too low and this is the not “excellence” in management of our time and money that will bring us success or prosperity from which we can bless others beyond our families. In my opinion, climate change has been a major distraction from the proper focus of agriculture on increasing long-term income and investigating value-added opportunities, finding more contracts or subcontracting for additional land use or a better site or a favorable agreement to secure access to additional land for production. We can compare at least two best management practices for each crop and hopefully even more so we can identity which practice results in higher income. We can experiment on a small scale and try new crops on a small scale and also find new markets. We really do not want to sequester carbon because carbon dioxide is fertilizer and based on what I have studied there are huge gains from increased CO2 in the atmosphere and the effect of CO2 on temperature is a diminishing curve. If the satellite studies from the last 30 years show a net greening effect (they do) then we are wasting huge amounts of time and money trying to mitigate something that nearly all the evidence points to benefit not harm. Yes there are winners and losers in climate change but only 5 % of the earth’s surface has had declining greening and 40% has increased in greening. The more we plant trees where there is little forest, irrigate, increasing cropped area with adequate fertilizer use and the more CO2 the higher the amount of greening. I really can’t understand why everyone is talking about climate change when the earth is actually greening and there are so many other more productive things to talk about which benefit the farmer such as what conservation practices improve yields in dry years and what can be done to invest in preventing flooding.