By Maeve Dunigan
As world climates continue to evolve, many regions are now faced with dwindling rainy seasons, affecting both traditional agricultural practices and overall crop yields. An ancient, but recently rediscovered land management system called agroforestry could be the solution to the problems associated with reduced rainfall, low soil moisture and carbon sequestration.
Agroforestry is the practice of growing trees or shrubs around and among crops combining both agriculture and forestry in a symbiotic relationship. The management system dates back to the time when humans transitioned from their one-dimensional hunter-gatherer subsistence and began to include agricultural practices as a means of survival.
According to Dr. Raghu Murtugudde, a professor at the University of Maryland (UMD) Earth System Science Interdisciplinary Center and department of Atmospheric and Oceanic Sciences, the precursor to modern agriculture was in fact borne amongst the trees.
“Coming out of the last ice age twelve thousand years ago [humans] started to domesticate crops … and [agriculture] was not done initially by clearing forests, it was done among the forests where there’s a clearing,” he said. “So slowly we got used to it [and] humans began to settle down.”
Murtugudde furthered that the key component in agroforestry is in the maintenance of soil moisture, despite respites in rainfall.
“The basic idea [behind agroforestry] is that the trees set the roots, so even if you have a year or two of drought they are able to keep the greenery,” he said. “That means the soil moisture is also maintained. For agriculture, soil moisture is the most important, even though we think rain is important, the farmer cares about how much soil moisture is collected during the rain.”
Increased soil moisture isn’t the only benefit of agroforestry. In countries such as India or Africa, the trees and green areas surrounding crops can also act as a natural barrier to limit animal intrusions.
“You use [trees] as a live fence most of the time,” Murtugudde said. “Because you have cattle walking around and stray animals, elephants sometimes, that can trample crops.”
Carbon sequestration, the process by which carbon dioxide is removed from the atmosphere and held in either a solid or liquid form, is yet another benefit of agroforestry according to Murtugudde.
“Scientifically speaking [agroforestry is] good because it increases carbon sequestration in the soil,” Murtugudde said. “If you have just agriculture then you’re putting the crops [in and] taking them out … if you’re not careful with the tillage you can increase soil erosion. But with agroforestry you are reducing that and you are increasing carbon sequestration.”
Murtugudde said that the switch to agroforestry is “definitely an investment of time and energy,” but “the benefits are more than compensated by the space taken up.”
Murtugudde first approached agroforestry not from the agricultural standpoint but as a water management system. This may seem unique, but agriculture and water use are linked, a relationship Murtugudde described as the “water food nexus.”
“[Agroforestry is] not only sustainable agriculture but it’s the best way to manage watersheds,” he said.