What happens when plastic mulch breaks down in tropical farms?
Hello friends,
I am writing today to share something important that can affect farmers in the tropics. We all have seen farmers laying out long stretches of plastic film in their fields to plant their crops. We have probably noticed that after a few months these films are often broken or torn and are left to decay in the fields. What happens to these plastic films as they decay is very important to the health of the soils used by these farmers and to the crops that they grow in these soils.
While the plastic mulch film is still intact, it prevents loss of water and helps to suppress weeds, but over time the plastic film begins to break down into very small pieces known as microplastics. These pieces of plastic are able to penetrate into the soil and be absorbed into the microbes that reside within it. The microbes in the soil are crucial for the soil’s productivity because they are able to break down nutrients that have been left in the field from previous crops, improving the structure of the soil and helping to produce strong healthy crops.
When microplastics enter the soil, they interfere with the soil’s biological system. Some soil organisms will die off and others will change in form and begin to behave in abnormal ways. The soil will become less diverse, which in the long run will make the soil weaker and farmers will harvest less while having to use more fertilizers to get crops to grow.
The problem becomes more critical in the context of tropical smallholder farms. In such environments, the farmers are already challenged to a great extent fighting an uphill battle to sustain their agriculture in the face of too much rain and scorching heat. The presence of microplastics in soil of such farms affects the way water moves in the soil, it affects the way roots of plants penetrate and interact with microbes and it affects the way nutrients are shared. And as time passes, the soil begins to lose its natural strength and the moment that happens, farmers in such farms are likely to harvest less and require more fertilizers to get crops to grow to desired heights.
The use of plastic mulch has both positive and negative impacts in the short term and long term. Although plastic mulch can give some temporary advantages for plant growth in the short term, the long term impacts of plastic mulch can be extremely negative. So that just means, the protection of soil microbes is equal to the protection of agriculture in the tropics.