As farm tractors and field equipment become larger and heavier, there is a growing concern about soil compaction. That may be why deep ripping tillage, meant to loosen the soil, is making another comeback. Deep ripper tillage demonstration is a daily feature at the Outdoor Farm Show in Woodstock, Ont. from September 13 to 15. Each manufacturer has a 200-foot strip of land to show off their machine’s skill at doing deep tillage to repair soil compaction.
The number one cause of compaction is operating heavy machinery on fields, especially in wet conditions. Farmers have been urged by the crop specialists to get the crop in early for maximum yields. But they are paying a hefty price for being on the land so early with heavy, soil-compacting equipment. Underneath the few inches of topsoil that look dry is wet, clammy soil that packs down quickly.
Deep ripping involves the use of strong, deep-working tines that penetrate the compacted soil, mechanically breaking up and shattering the soil’s hard pan. For deep ripping to be effective the ripping tines must be able to penetrate just below the compacted soil layer.
Too much traffic
Fifteen years ago I went to a deep ripper tillage demonstration held at a neighbouring farm, put on by the local Case IH dealer. A 12-foot-wide ripper on a 185-horsepower tractor ripped up heavy clay ground in a cornfield. Case IH had a crop specialist employed by the company from Goodfield, Illinois, over for the two-hour field demonstration. Farmers watched with interest, but no one bought into the idea of buying such a high horsepower tractor to pull a ripper.
Some soil experts have said deep ripping can do more harm than good. When a ripper moves across a field it digs up rocks. In studies, yields are only slightly up if at all. According to a study by the University of Minnesota, consistently higher yields through deep tillage are hard to find in parts of the Midwest.
Another reason cited for the failure of deep ripping to remove a compacted layer is that subsequent wheel traffic may have reintroduced the compacted layer. A loosened subsoil will have very little bearing capacity, meaning it can’t support much weight. Controlled traffic becomes even more important.
Before setting the depth of the ripper, the Case IH crop specialist had a hole dug in the field 16 inches deep and 20 inches wide. He said it is important to know how deep the compaction is in the field. The probe, he said, is unreliable in finding the compaction layers.
The crop specialist said the most reliable way is to dig a hole with a spade or a backhoe. Clean one side up to be a vertical wall. Then use a knife tip to pull up through the soil. He showed how the blade tip will find the problem areas that hinder root growth and water penetration. Measure the depth of the layer and run the chisel points one to two inches below the layer for best results.
He had many of the farmers pulling the knife tip through the hard ground. There were three hard compaction spots at different levels. Then the ripper machine was set so it would go down 12 inches deep to take out those hard layers.
“We want the raindrops to soak in where they land, so [the water] can be used later by the crop instead of causing erosion,” he said. “Corn roots can go down five feet to find moisture if the hard compaction is taken out.”
Is it worth it to go over the field twice? Probably not, as that would only cause more soil compaction. No matter how you look at it, deep ripping is a costly operation, which farmers must factor in when seeking the benefit of improved crop yields.