In honour of World Environment Day on June 5, we look at what dairy farmers are doing to improve soil health while reducing carbon dioxide emissions from soil.
How does conventional agriculture impact soil health and the environment?
Growing crops for human or animal consumption can use intensive practices that may result in erosion, nutrient and moisture loss, water pollution, as well as greenhouse gas emissions. In British Columbia, agriculture contributes approximately 3 per cent of the province’s total greenhouse gas emissions (BC Government, 2016).
One main culprit behind carbon dioxide (CO2) emissions from soil is the intensive land tilling conventionally used to prepare seedbeds and ward off intrusive weeds that could interfere with crop growth. By turning up roots and organic matter from previous crops, tilling the land destabilizes soil composition, which causes the release of CO2 into the atmosphere.
What is being done to improve soil health?
Conventional tilling is becoming less conventional, with many farmers adopting the following approaches to address soil conservation.
1- Conservation Tilling
Conservation tilling is an alternative to conventional tilling, where many farmers have started implementing practices that minimize or eliminate tilling altogether. By reducing tillage before planting, crop debris and old roots from the previous season stay in the soil and provide nutrients that help maintain soil health. This leftover organic material helps keep the soil intact, which reduces the risk of runoff and erosion, protects the soil from nutrient and moisture loss, and reduces emissions by locking in carbon.
2- Buffers and Agroforestry
Planting trees and shrubs in and around fields and pastures, called agroforestry, provides additional soil protection. This kind of vegetation enhances the benefits seen with conservation tilling, and further reduces emissions by absorbing CO2 and releasing oxygen. Many farmers plant rows of trees close to ditches and waterways that act as buffers for any potential runoff. With agroforestry, some dairy farmers can also gain the additional benefit of extra shade for their cows when they are out at pasture.
3- Cover Crops
Planting cover crops such as grasses and legumes in between crop seasons is another mitigation technique that farmers are using to address soil health. Cover crops act to protect the soil from wind and rain related erosion and runoff, control weeds, and retain soil nutrients that enhance bioactivity in the soil.
Dairy farmers gain additional benefits from certain cover crops as well. Cover crops enrich the soil with nitrogen, which yields higher forage productivity. For example, if a farmer plants a cover crop of clover before a crop season, the harvest that year will have higher nutrient value and when fed to dairy cattle, will produce higher milk yields.
Combining these measures has many benefits:
It helps protect soil from erosion and runoff.
It helps maintain water health.
It reduces emissions.
It adds nutrients and improves soil health.
It yields three times more than the conventional alternative.
Happy World Environment Day!