Manure vs. compost — which is the better choice?   Here are a couple of clues:

  1. The best thing about raw manure or poultry litter? It’s free.
  2. The best thing about compost? It works.

Here’s why:

  • Organic material (OM) is added to soils through manure decomposition.  But the amount is about equal to the amount of organic matter lost through natural processes. That’s why you may see no rise in field OM even after years of manure applications.  Compost adds stable organic matter.
  • Compost is a concentrate.  The amount of compost required is much less than the amount of manure required.  This helps to cut total number of trips over the field.
  • Compost keeps water and fertilizers at the root zone, mitigating fertilizer leaching, erosion and topsoil loss.
  • The natural microbial activity of compost does lots of good things for soil which, in turn, does good things for plants. Researchers report improved nutrient uptake and resistance to pests and diseases.
  • Compost is best for pasture and hay fields where raw manure applications can reinfect livestock with internal parasites, bacteria and viruses. Compost may be more palatable to grazing horses than untreated manure.

In the compost vs. manure debate, compost is the clear winner.

Learn how quality compost is manufactured

Section 2(d) of Executive Order 13514 establishes a 20 percent water reduction goal for federal agencies by fiscal year (FY) 2020 relative to baseline use (FY2010).

A reported 87 percent of all water consumed in the U.S. is utilized for irrigation, with “consumed” meaning no longer available for other purposes. An estimated 80 percent of consumptive use is by agriculture, as much as 90 percent in the western states.

Whether at home, in the landscape or on-farm, more efficient irrigation systems, moisture monitoring and other best management practices (BMPs) for water management are certainly important conservation tools. But compost use has been proven to reduce water consumption by 30 to 50 percent, because as organic matter (OM) content of soil goes up, water use goes down.  Optimum recommended OM content is 5 percent.

Compost is 40-50 percent organic matter and a better choice than either raw manure or peat moss to replenish and maintain OM at ideal levels.

For the typical 5,000 sq. ft. lawn, bringing soil OM content up 5 percent saves about 9,400 gallons of water a year. In the U.S., a national policy supporting a 5 percent increase in organic matter content just for single family detached homes (91+ million) would save about 855 billion gallons a year.

That’s the approximate volume the Mississippi River dumps into the Gulf of Mexico every three days and would be enough to water all the golf courses in Florida for the next four or five years or provide water for the City of Raleigh, NC, for the next 50.

There are more than 61.1 million irrigated acres in the U.S. – about six times the surface area of all suburban lawns. Six times 855 billion gallons saved is more than 5 trillon gallons every year.

If everyone (federal government included) with an irrigation system would raise the organic matter content of those irrigated landscapes and cropland to 5 percent and keep it there, the impact on water use would be staggering.

The simultaneous impact on stormwater runoff is also an eye-opener, but we’ll save those mind-boggling numbers for another day.

Resources for this post: consumptive water useU.S. irrigated acreage