The Effects of Manure on Agricultural Soils

What is manure and why is it so important?

Manure is an abundant organic fertilizer in Langley, as well as a source of macro and micronutrients for agricultural soils. According to Fertilizer Canada “Fertilizers are food for plants. Just as we need an adequate and consistent diet to grow and stay healthy, plants and crops have to get proper nutrition from the soil to thrive”. Manure fertilizers greatly increase the amount of soil organic matter, improving the physical, chemical and biological properties of agricultural soils when applied, therefor, improving water filtration, enhancing nutrient retention, decreasing wind and water erosion, as well as promoting the growth of beneficial soil organisms.

Some issues with manure fertilizers

Ruminants like cattle and sheep are sources of methane and account for approximately 18% of global anthropogenic emissions via their digestive processes. Manure also releases significant amounts of methane and nitrogen dioxide during storage. In order to decrease the amount of emissions released during storage, manure can be covered with tarps in solid form rather than liquid, and livestock feeding practices can be altered and pasture quality improved.

Manure run-off and soil erosion can carry soluble and particulate nutrients into waterways. In particular, fecal coliforms in Langley waterways have the potential to be point and nonpoint source pollutants. Fecal coliforms enter the Sto:lo (colonially known as the Fraser River, the Nicomekl (Nicomekl River) and the Nuxwsá7aq (Nooksack River) in Washington, eventually draining into the ocean at the Strait of Georgia, Boundary Bay, and Bellingham Bay, greatly affecting traditional shellfish harvests.

The benefits of manure application

  • Source of plant nutrients (in particular N, P and K)
  • Improves soil quality
  • Maintains soil pH
  • Improves soil physical properties
  • Increases crop yield

Cattle manure which has been traditionally used in arid and semi-arid regions in China to combat salinization have been found to increase water retention and infiltration, decrease soil bulk density, and improve pore space necessary for root growth and microbial activity.

Inorganic fertilizers

The use of manure fertilizers has decreased due to the use of inorganic or synthetic fertilizers derived from nonliving sources. The synthetic fertilizers most used by farmers in agricultural soils are N, P and K fertilizers. Inorganic fertilizers are manufactured to dissolve readily in water and are immediately available to plants for uptake. Inorganic fertilizers have been somewhat successful in meeting global food requirements however they have presented economic, environmental, and social problems. In particular, soil and watershed health have been severely impacted by present-day agricultural practices.

Organic amendments like manure present a more favorable fertilizer option to maintain soil health as it is cost-effective, abundant, and more sustainable. However, if applied and stored incorrectly it can have severe downstream effects. LEPS will be hosting a series of webinars on these topics if you would like to learn more. Keep an eye out on the monthly newsletter and calendar!


Some helpful links!

Land Management Guide

Manure Link

Improving current manure management practices

Storing Manure on Small Horse and Livestock Farms

Managing Manure as a Fertilizer

What Does Organic Matter Do In Soil?

When to Spread Manure

Previous Webinars

By Sophia Nguyen