Manure & Pastures- That First Flush
/By Michael Hipp
Fall is quickly approaching, and your horses have been grazing all summer on your nice, lush pastures you’ve been nurturing for a long time now. As the fall and winter rains begin and you will move your horses off the pasture for the winter, I always get questions about what to do with the manure the horses have left behind. Many of our streams and creeks, even our “seasonal” waterways, flow to important spawning beds for salmon and other species in freshwater and to shellfish beds in marine water. Manure and pasture management are very good questions to consider as we approach what is called the “first flush” of the season. I’m not talking a flush of sugars into the fall grass like we normally refer to, but that first heavy rain of the fall that “flushes” waste products such as manure from our pastures. Fortunately, there are some options to help us prevent this.
Harrowing
My first go-to for end of the season manure in the pasture is to harrow the manure as it lies in the pasture. Harrowing breaks up the manure and exposes it to sunlight (UV rays) that will kill parasites. Harrowing also exposes more surface area to dry up the manure and allow it to break down to be incorporated into the soil. Plan to harrow on a sunny, warm day when dry weather is expected over a few days or more. Never harrow when it’s raining, as this will only increase the chances for runoff.
Picking
If at all possible, picking the manure out of the pasture is a good option. Collecting manure from pastures decreases the potential for manure-related bacteria and nutrients to contaminate surface water runoff, and doing so allows you to compost and use it again. However, picking becomes unpractical the more horses you have and the fewer times you do so. If you have only one horse and can pick at least once a week, that is ideal. But if you have more than one or two horses it may be more of a chore than you can handle. Picking at least once a week is ideal so that at the end of the season you don’t have too much to do and become overwhelmed by the task. If you have more than one horse, than picking at least twice a week will be more feasible.
Leave it Alone
Yes, this is an option, though not the best. If this is the only practical solution for you, due to personal constraints or physical ability, though it does come with some requirements in order to be safe:
Ensure the pasture is healthy enough – sustainable grass height (minimum grass height of 3 inches and a maximum of 12 inches), healthy soil and soil chemistry – to absorb the nutrients left behind.
Maintain an adequate buffer of either tall grass or native vegetation between your pasture and any waterways nearby, even if those waterways are seasonal.
Ensure that your horses are as free as possible from any parasites that could multiply if left in the pasture and thus become a burden next season.
Preventing manure runoff by whichever option you choose (or a combination) is vitally important to protecting the health of our surface and groundwater all around Puget Sound, especially the waters in shellfish growing areas and those used by our salmon and orca populations. By making sure you are practicing good pasture management, which includes taking care of the manure left behind, you can play a very important role in the recovery and protection of our iconic wildlife populations.
This project has been funded wholly or in part by the United States Environmental Protection Agency under assistance agreement PC-01J18001 to the WA State Dept. of Health. The contents of this document do not necessarily reflect the views and policies of the Environmental Protection Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.
This project has been funded wholly or in part by the United States Environmental Protection Agency under assistance agreements 01-J18101 to the WA State Dept. of Ecology and PC-01J18001 to the WA State Dept. of Health. The contents of this document do not necessarily reflect the views and policies of the Environmental Protection Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.
