Tue, 09 Jul 2019
Two drone enthusiasts have devised a new invention that allows drones to plant large numbers of seeds in minutes.
South African Andries Louw and Australian Andrew Walker built a pneumatic firing module that shoots seeds into soil.
It can spit out two seeds per second at velocities of anywhere between 150 and 300 metres per second. This is faster than the cruising speed of a passenger jet.
The module, called it Podder, can attach to the bottom of popular drone models. Louw and Walker estimate that a team of two, flying 2 drones, can plant up to 40,000 seeds into into the ground in a day. In just ten minutes they can plant what the average human can plant.
The first module was built in a garage in Hermanus, but since then Louw, a certified drone pilot, and Walker, a mechanical engineer based in Sydney, have founded a company called AirSeed Technologies, and hope to use their technology to address deforestation.
Deforestation is the second-leading cause of climate change after burning fossil fuels and accounts for nearly 20% of all greenhouse gas emissions — more than the world’s entire transport sector.
A fleet of their drones could plant 100 million trees a year from 2023, the duo believes.
“Reforestation is where everything starts. Worldwide there is a deficit of 14 billion trees a year, which equates to 1.26 million metric tonnes of lost carbon sequestration every year,” said Louw.
It is a costly business – an average tree costs R30 to plant in Africa. Louw says they can reduce this cost by as much as 70% using drones. The cost is so high because most of the work is done in remote areas which are hard to reach and even harder to plant by hand.
An average hand planter manages around 800 trees a day, said Louw. And it can take long. Germinating the seeds can take anywhere between 3 months to 2 years, depending on the tree.
It’s not the first time seed-planting has been done by air, but the success rate of germination is low.
Drones have also been used, but Louw says payloads have been limited to 150 seeds per flight due to the weight of the seeds, which also needed to be pre-germinated.
So, AirSeed designed a carbon seed pod made from a soil additive called biochar to make them lighter. This highly compressed charcoal is made from the thermochemical conversion of biomass.
The balls come out looking like black paintball bullets. They’re light, weighing as little as 5 grams, and strong – which also means there can be up to a thousand seeds in a single payload.
By compressing seeds into the biochar, the pods act like a natural fertiliser. The seeds also don’t need to be pre-germinated as the carbon is nutrient-rich and can be infused with land-specific microbes and fungi.
“Without the seeds the entire project would mean nothing…We had to come up with a solution for the payload that was light; that was viscus, in other words smooth; that was durable and would not break on impact; and that protected the [...]