Agricultural production accounts for about 15% of global greenhouse gas emissions, rising to almost 30% if you include land-use change due to agriculture. So any technology that allows us to increase agricultural production while reducing emissions is extremely welcome. Here are a few I have come across recently:
1. Biological nitrogen fixation: getting legumes like soybeans to absorb more nitrogen from the atmosphere. This is standard practice in soy-growing regions like the US Midwest and Argentina, but a lack of rhizobial bacteria in the soil held it back in areas like Western Kenya, until the advent of a program to introduce the bacteria to the soil directly. Result: higher yields and less need for nitrogen fertiliser, which is expensive and a major source of greenhouse gases.
2. ‘Alley cropping’ at Wakelyns Agroforestry in Suffolk, UK. The idea here is to integrate trees and crops – less convenient for large machinery, but better at sequestering soil organic matter and less resource-intensive than monocultures. (Thanks to Louisa Winkler, who works there, for telling me about this project).
3. The use of ‘zaï’, planting pits, in dry areas of Mali and Burkina Faso. The simple expedient of digging a shallow pit, filling it with organic matter and allowing it to capture rain and prevent seeds from being washed away seems to have led, over a number of years, to increased agricultural yields, greater food security and the gradual reforestation of previously degraded areas.
4. Finally, one more from Western Kenya: a soil carbon fixation project. It relies on tried and tested techniques like agroforestry, intercropping, mulching and manure – none revolutionary in themselves, but powerful when applied in combination. This project has been certified under the Voluntary Carbon Standard, which should provide a useful cross-subsidy as long as voluntary carbon markets remain in business.
The more I learn about initiatives such as these, the more I wonder why we struggle to scale them up? Is there some sort of conspiracy by the fertiliser industry to suppress alternative techniques? That seems unlikely to me. Most crop scientists I know (including those who work for fertiliser companies) seem to me to be people of great learning and scientific integrity; indeed, I have spoken to fertiliser makers who acknowledge that while many farmers (especially in Africa) don’t use enough fertiliser, others (including in China and India) use too much of it, usually because it is subsidised, or other soil nutrients have become depleted so that adding more nitrogen is ineffective.
Alternatively, is it just a problem of limited education and access to information? Certainly I would imagine the average farmer struggles to assimilate such as the International Assessment of Agricultural Science and Technology for Development – I certainly did. However, the spread of mobile phones, new roads and widespread migration makes it easier to spread information than it was even ten years ago. In a region as densely populated and well connected as Western Kenya, one would expect very rapid adoption of agricultural technologies that have been shown to work, especially if they are low-cost.
This problem may not be unique to agriculture, however. In this fascinating TED Talk, Sendhil Mullainathan lists some critical social problems that have extremely simple solutions but have not yet been solved. For example, fewer than 50% of Indian women know that diarrhoea can be solved by cheap, simple oral rehydration therapy that has been around for decades; many of them believe they should give sick children less to drink, not more. Only 75% of diabetics in the USA inject insulin every day – even though the other 25% know that failing to do so could make them sick, even blind. Intercropping has been used to raise crop yields all over the world for centuries, yet few farmers use it and some who used to do it no longer do because they found something more ‘modern’. Why?
Sendhil calls it the ‘last mile’ problem: you can gather all the data and evidence you want, but until people are persuaded of something emotionally, by experiencing it or living it, they won’t change their behaviour if the change is counter-intuitive. This isn’t a problem limited to poor farmers or Indian women or American diabetics. It affects us all at sometimes. Unfortunately, while psychologists and behavioural economists are working on how to ‘nudge’ us in the right direction, there are no easy answers. It takes a lot of time, experimentation and patience.
A few weeks ago, I went for a long run in the hills above Addis Ababa. As you would expect, it was slow going, especially the stretches over 3,000m. The last mile was the longest: a series of hills with false summits, followed by a blissful downhill stretch. For us to make a meaningful impact on agriculture and climate change here is going to be like doing that run a thousand times.
