Spring rains can come hard and fast. Fields at this time are most vulnerable to soil erosion, as they often lack enough crop residue after planting and the crop canopy isn’t yet present to protect soil from the impact of driving raindrops.
“Now is the time to evaluate your soil conservation practices,” says Paul Goldsmith, district conservationist with USDA’s Natural Resources Conservation Service at Creston. Storms this spring have dumped heavy rain on parts of southwest Iowa and other areas of the state. Even fields that are fairly flat to moderate in slope have suffered some significant erosion.
“Look for places in your fields where soil has washed away. It’s obvious where grass waterways are needed,” he says. Properly designed and maintained grass waterways and buffer strips can be valuable in reducing soil erosion. Also, check to see how your existing grass waterways are working. Do they need repair or reshaping?
Keep things clean
Terraces and standpipes should be checked and cleaned. Excessive rain can cause damage to these structures, and it’s important to make repairs, even if the repairs are only temporary. Terrace channels and inlets for drainage need to be in good working condition. Remove crop residue and silt that’s accumulated around inlets and outlets.
If soil moves into terrace channels, terraces begin losing capacity to hold water and can eventually start overtopping. When terraces overtop, the water cuts the terrace, causing drastic damage. “It’s critical to remove silt from around the intake and keep the terrace channel maintained so water can run all the way to the intake and drain away,” says Goldsmith.
Roger Ide and wife Jean have a number of terraces and grass waterways on their farm near Creston. This is Ide’s 50th crop year of farming. He’s been no-tilling corn and soybeans for 25 years. The family also has a sheep flock, making good conservation use of hilly pasture ground.
“Permanent structures such as terraces and grass waterways are very much needed,” says Ide. “But using them in combination with no-till, you can do so much more to keep soil on the field and out of creeks and rivers, especially with the heavy rains we’ve had the last four years. We’re getting pounded by big storms this spring, too.”
Contouring also helps. “By planting no-till on the contour, the erosion is a lot less compared to fields where tillage was used,” he says. “When you get a 2-inch rain in 30 minutes on ground that’s already filled with moisture, you’ll have some soil movement, even in no-till. But the erosion is much worse on tilled fields.”
Still too much tillage
Besides saving soil, no-till saves time and fuel. “Everyone should be using no-till,” says Ide. “It’s not complicated. It’s not difficult to overcome the challenges.”
Too much tillage is still being done on some of Iowa’s most fragile ground. “That costs time and money, too; it’s not just a loss of soil,” says Ide. “No-till planters, sprayers and weed control systems have really improved. Planters built for no-till can plant through crop residue. It just takes some effort and patience to learn how to put your system together and make it work.”
He adds, “I’m not saying I do everything right. I learn something every day. But Mother Nature is presenting some big problems. Using no-till in combination with permanent conservation practices is helping us cope with these intense rains.”
Goldsmith has seen some no-till fields being farmed up and down the hills instead of on the contour. With heavy rains, water runs down the rows and takes the corn out, washing it to the bottom of the hill. “Using a combination of conservation practices to help slow the runoff is very, very important,” he emphasizes.
HEAVY RAIN: Terraces need periodic care and maintenance, notes Roger Ide, a Union County farmer. With relentless storms, silt and crop residue can move into a terrace channel and need to be cleaned out from around the intake so water can drain away.
This article published in the June, 2011 edition of WALLACES FARMER.
All rights reserved. Copyright Farm Progress Cos. 2011.