Monday, August 2, 2010

S is for Soil

Melissa has made reference several times in her blog to my cash cropping background. I also have a long history of raising cattle, and I've been known at other times to raise hogs (and board horses), but at all times I am at least as interested in what came out their rear ends as I am about eating, selling or keeping the animals. While it has always been important to me to raise and care for livestock properly, at heart what I am really interested in doing is growing things that will help me build soil in productive ways.

In Ontario, I farmed excellent, dark brown class 1 stone free, deep loamy agricultural soil. It was naturally fertile and naturally very friable, with lots of organic matter and an unamended soil pH of 7 to 7.3. About the only further amendment I made to it in order to make it as productive as possible was systematic tile drainage and that was more to warm the soil up evenly in the spring than anything else. From a soils perspective, I really didn't know how good I had it until I moved to Tennessee.

I moved down here because I fell in love with my wife, who was from here and who made it very clear that she wasn't built to handle much cold weather. It took a little time, but I fell in love with the place, too. It's pretty, and excepting for a few hot weeks in the summer, it has a pretty salubrious four season climate, in my opinion. But the soil mostly sucks. We bought pretty good soil on our new place, but you have your pick of adjectives (preceeded by cuss words) to describe conditions on my in-laws place where we live right now. Think cherty, stony, infertile, highly acidic. high Sulfur, unproductive, shallow, steep heavy clay. It'd be excellent stuff to make bricks out of; it's hellish bad to work, and it should NEVER be put to the plow. It's best agricultural usage is permanent improved pasture, except in places too steep or stony to be grazed. There, the best use is trees.

Improving this soil to increase it's productivity in a sustainable manner is an ongoing challenge, but the good part is that it has lots and lots of room to improve, and it's easy to see when I manage to get something right. Unlike my gardening friends, on a farm this large I can't afford to buy my way to fertility quickly, so I have to focus on building it slowly but the same principles apply.

Soil organic matter burns up down here at a furious rate, so we spread as much OM as possible in an effort to battle this. Spreading copious quantities of ag lime improved the soil pH in the root zone from a little over 5 to a little over 6. We've still got a good ways to go here and we'll continue spreading lime as money permits. I've pretty much ignored NPK recommendations on our soil tests so far because until the soil pH improves it isn't going to get uptaken very efficiently by plants anyway.

We probably saw our biggest response from spreading small amounts of Mg and Cu. These aren't necessarily deficient here, but they act like it because they are bound by high levels of Sulfur in the soil and adding them has made every plant (including the weeds) perform more vigourously than they did before. It's also exciting to watch the weed profiles change, and it's another good indicator that we're starting to improve fertility. I'm probably the only farmer in Middle Tennessee who gets excited when he sees broom sedge give way to pigweed !

Livestock manure, incorporated in appropriate amounts, is the key to building soil fertility quickly and sustainably. This is most evident on the shallow soils which is where I choose to feed round bales to both cows and horses in the winter. In the spring I harrow in the wasted hay and copious amounts of manure and I sure feel like I accomplished something pretty great in those spots, especially when I can rotate cattle through it.

I would *love* to figure out a way to rotate horses across a pasture in a manner similar to cattle but also in a way that gave them adequate room to move around without the lower animals getting beat up. I've done a lot of reading about it, but I'm not there yet. Anyone doing this at home ?

1 comment:

Kate said...

We've done some rotational grazing with subdivided pastures. We don't do it much anymore as we have too few horses now for it to really work. We would keep 6 or so horses on about 1 acre for about a week, and then move them. Now we just mow. The pasture shape is important, and where the water tank and gates are, to avoid crowding and injuries. Long, skinnier pastures work better for the horses - they like to run to the back and graze things more evenly. Your existing pasture configuration may limit what you can do.

We have very deep, heavy clay soils here too - they should also never have been plowed. Very nasty, gluey stuff when wet and hard as rocks when dry - but incredibly fertile and great for growing grass - in fact our problem is usually too much rather than too little grass.