Living fertilizers: bacteria that boost sustainable agriculture 

More than 10,000 years ago, our ancestors left nomadic life behind to settle in one place and become farmers. Let’s say that at some point in our evolution we chose to obtain food from the land itself rather than travel long distances. You already know this story: thanks to agriculture, the population grew, and more and more settlements were created until the first cities emerged. And the most striking thing is that it never stopped growing. 

Today we have many more mouths to feed. In fact, the world population is expected to reach 8.5 billion in 2030, 9.7 billion in 2050 and 11.2 billion in 2100, according to data collected by the United Nations. And today, once again, the key to our history is marked by agriculture. 

Aren’t we asking too much of the soil? 

To meet current and future food demand, FAO estimates in one of its latest reports that by 2050 agriculture will need to produce at least 50% more food, livestock feed and biofuels than in 2012. But how will we feed billions of people when there is less and less arable land and more extreme weather conditions? 

At the beginning of the 20th century, the problem of producing more food found a solution in artificial inorganic fertilizers, accompanied by the intensive use of natural resources and large inputs of chemical pesticides. The results were as expected: an extraordinary increase in food production around the world was achieved and the goal of saving lives was fulfilled, a leap in food production that went down in history as the so-called Green Revolution. However, the jump in agricultural yields did not come for free and today we are experiencing some collateral damage up close. 

Beyond the green revolution: a sustainable future 

The problem with inorganic fertilizers is, firstly, their excessive use. Another drawback is that the plant does not always manage to absorb the chemical in time and water and wind remove the fertilizers from the surface. This is precisely the starting point for a series of unfortunate events, because excess nitrogen and phosphates infiltrate groundwater or are washed into surface waters. 

The consequences are manifold: intoxicated people, excessive algal blooms in the water that choke other forms of life, soil deterioration, increased greenhouse gas emissions and even greater dependence of crops on chemical inputs. 

We need a change. And, according to FAO, we will achieve this by making agriculture and food systems more sustainable so that they help us reduce rural poverty, ensure nutrition for all people, care for the environment and address climate change. We are talking about a change that can begin by reversing soil degradation and, in this sense, there are already innovative proposals that offer alternatives to conventional fertilizers. 

Bacteria to enrich degraded soils 

Some years ago, microorganisms capable of mimicking the benefits of chemical fertilizers began to be studied and could function as the perfect complement for a more sustainable agriculture. 

Bacteria have a bad reputation, but many of them are beneficial to humans and ecosystems. Studies indicate that the genus Rhizobium and other bacteria would be able to restore soil resilience, increasing crop productivity in a sustainable way. How do they do it? Thanks to the symbiotic relationship they establish with the plant, these bacteria form nodules on its roots and supply the plant with nutrients from the soil and nitrogen from the atmosphere. 

As if that were not enough, they are also living pesticides, producing plant hormones that act as chemical messengers (phytohormones) that regulate plant growth and reinforce its defences against external aggressions, such as attacks by insects, fungi and pathogenic bacteria. 

Will bacteria be able to lay the foundation for new practices? Can they help agriculture meet the challenges of the coming decades? It is still too early to tell. First, it is necessary to define aspects related to large-scale application and to study in depth their long-term effects on the environment. We will follow this type of proposal very closely.