Gardeners in the West don’t like it when ants build their homes between rows of flowers and produce. Smallholder farmers in Africa also find ant and termite nests in their fields a nuisance. Thus, research published last year explored how farmers can control ant and termite infestations with integrated pest management strategies. The authors see termites as a particularly dangerous pest for Ethiopia’s farms, noting that farmers try to control them through smoking or “mound opening,” which implies ripping them apart.
At some point in the distant past somewhere, a farmer must have knocked down a termite mound or anthill intruding on his field only to discover later that the crops grew better at that spot. We’re guessing this because while ants and termites can damage crops, for centuries farmers in sub-Saharan Africa have been deliberately seeking out abandoned termite mounds and anthills to use as fertilizer.
Earth Day is coming up, and April has been unofficially designated as Earth Month. To honor the occasion, we’re exploring how earth—meaning soil—can be transformed to help smallholder farmers grow more food. In the case of anthills and termite mounds, the insects have done the soil transforming for us.
Grow Further explored the topic of using abandoned ant and termite nests as soil amendments a few years ago. Farmers have known about this trick for centuries, but it’s a concept that agricultural scientists are still digging into (pun intended) and an example of the sort of scientific application to indigenous techniques that Grow Further finds interesting to fund.
Beneficial insects, sometimes
Termites and ants damage plants in the wild, so, unsurprisingly, they can pose threats to crops. They also fill valuable ecosystem functions thanks to the type of nests they build for their colonies.
By churning soil inside out, ants and termites aerate it. Their nests can also create pore spaces that make it easier for soils to capture, distribute, and store water.
Ants and termites drag food underground into their nests and deposit wastes there, too. Many ant and termite species are careful to quarantine waste to avoid infections and disease outbreaks, but these waste chambers are usually below ground in separate chambers.
These insects can also introduce beneficial bacteria deeper into soils. For all these reasons and more, many agricultural scientists are arguing that smallholder farmers struggling with high fertilizer prices could cope by spreading their fields from anthills and termite mounds, both of which are often massive in parts of sub-Saharan Africa.
“Anthill soils posses higher total bacterial counts and superior physiochemical properties compared to adjacent soils, except for silt, sand, and pH levels,” two scholars from the University of Benin in Nigeria said in research published back in December.
In their study, the research pair mined and analyzed soils captured from anthills found not too far from their university. They tested these samples in the lab while also testing the conditions of adjacent soils as a sort of control group. They discovered that the insect-tilled soils hosted an abundance of beneficial bacteria, microbes that can help crops grow better. “These bacteria exhibit important plant growth-promoting functions, such as phosphate solubilization and ammonia production.” The study was published in the Nigerian Journal of Biotechnology.
The anthill soils were also found to be rich in calcium, magnesium, potassium, and phosphorus. That last one, phosphorus, is critical for plant growth. The researchers said their findings confirm that anthill soil can be “an asset for sustainable agricultural practices.”
The whole mound
Another recently published study, also out of Nigeria, has unearthed evidence that termite mound soils might be perfect for farming sorghum.
Publishing in the Nigerian Journal of Entomology, the researchers dug deep into the properties of termite mounds as they analyzed the different soil nutrient profiles of different layers of the mounds. They ultimately determined that there wasn’t a huge difference between the outer and inner layers of termite mounds in terms of how crop growth responded. However, they’re left with no doubt that crops do grow better when termite mound soils are employed as a type of fertilizer, one better suited to smallholder farmers due to its “availability and affordability.”
“The results revealed an increase in crop growth on a plot treated with whole termite mounds soil rather than a particular layer of the termite mound,” they said. They tested these soils with sorghum because that crop is a major staple in African agriculture. They ultimately conclude that this is probably good news given “how tedious and time-consuming it could be to sort the different layers of the termite mound for soil amendment.”
Insects beneficial in a different way
Many food security advocates have long argued that we should grow and consume more insects as a food source. Few have suggested that we should employ insects to help us grow more food—the conversation is usually centering on ways to keep bugs out of our fields and off our crops.
Unless they’re deemed beneficial insects, like ladybugs or nematodes, it’s generally a good idea to keep insects at bay. With anthills and termite mounds, we’re presented with an interesting concept of using insects to help grow our food indirectly. Perhaps instead of massive insect farms with the bugs considered the food source directly, some innovative thinker will find a way to wrangle ants and termites in the service of manufacturing soils rich in beneficial bacteria, nutrients, and minerals that will help us boost yields without reliance on expensive, synthetic fertilizers.
— Grow Further
Photo credit: A termite mound in Pilanesberg National Park, South Africa. Bernard DuPont, Flickr Adam/Creative Commons (CC-BY-SA 2.0).
