Fresh Water Is The Primary Soil Nutrient You Should Be Managing For
By Steve Kenyon
Reprinted from the Stockman GrassFarmer
BUSBY, Alberta: A problem we have in agriculture is that the water cycle is generally broken. To see what I mean let's look at our fields or pastures when it rains at a microscopic level.
Without a protective layer on the surface of the soil, a raindrop comes hurling to the ground and impacts the soil. It is like a small explosion that destroys the soil structure. Breaking apart the aggregates, this damage causes soil capping. This leaves a smooth surface that the next rain drop can't penetrate.The rain no longer has anywhere to go, so it runs off. As it runs off of the land, it takes with it the best parts of the damaged aggregates and our valuable humus is washed away.
What moisture did get into the soil is now vulnerable to evaporation. The moisture in the soil does not work by gravity. It actually works by diffusion. This is a movement from an area of greater concentration to an area of lesser concentration (wet to dry).
If the top layer of soil's moisture is evaporated by the sun and the wind, the lower moisture will then move up to the dryer area. It will then begin to evaporate and more moisture will move up. Suddenly our water cycle has been reversed. As this moisture moves up through the soil and evaporates, it can also bring with it unwanted salts that can be detrimental to growth.
With a healthy water system, our water bodies will evaporate and the moisture will rise up and form clouds. These clouds will then get dense enough to form precipitation and fall back to the ground as rain. Here we need the rain to soak into the soil and infiltrate through the soil to again replenish the water bodies which will again have the moisture evaporate.
So how do we stop this unhealthy cycle? Leave more residue. We need to make sure that the first rain drop cannot hit the exposed soil. It needs to land on live or dead plant material, as that rain drop will then break apart and soak into the soil without damaging the soil structure.
If the soil is in good health, the organic matter will hold onto the moisture. Excess moisture will infiltrate down into the soil and away to larger bodies of water, thus filling them from the bottom and not from run off.
I believe that in the future, water is going to be a very valuable resource. Ask anyone from California. Holding onto water and protecting riparian areas will be an important part of maintaining our ecosystems and our industry. If this means that water bodies and ponds appear on our land, so be it. This is a good thing.
In a lot of agricultural practices we end up destroying these riparian areas in the name of profit. The most limiting factor we have in many areas is water. To produce a crop, you need upwards of 200 times more water than you need nitrogen. Which do you think is a more important nutrient?
It frustrates me when I see grain farmers ditching their fields to drain away wet areas. Yes we get to farm a few more acres, but at what cost?
How much flooding occurs downstream because of it?
How much topsoil is washed away with It?
How many riparian areas are destroyed?
How much biodiversity is lost?
Do you know who is responsible for most of the biodiversity in North America? Long before we were ever here? Our friendly, hard working beaver, that's who!
To make a home, he backs up water. He causes his environment to flourish in biodiversity because all life needs water. Plants, animals, fungi, insects and birds all rely on water and thanks to the beaver, they can all thrive with abundant riparian areas. Each ecosystem relies on the other and it all starts with water.
I know that some folks will be offended by this article as we have all grown up fighting against the beaver, hunting him, and cussing him. It is a paradigm, but just for a moment, sit back and think about what your area would be like without him.
I am not saying that we never have to manage the beaver. Environments can get out of balance, predators are sometimes scared off and we might need to re-balanced the system again. But if we do, we need to figure out how to work with the beaver and allow him to do his job as well as letting us do ours. All relationships need to be win:win.
Fresh water should be the number one nutrient you are trying to manage. Without it, agriculture will cease. Try to build your soil and rebuild a healthy water cycle. The sustainability of agriculture depends on it.