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February 2013 Archive for Ask an Agronomist

RSS By: Farm Journal Agronomists, Farm Journal

Have your agronomic questions answered by a Farm Journal agronomist. E-mail us directly at, and we’ll respond on this blog to provide an interactive dialogue.

Will My Disk Chisel Shatter a Hard Pan Better than an Inline Ripper?

Feb 28, 2013

Question: I have a piece of ground that has a hard pan at 10" to 12" deep. I am looking to move to vertical tillage. Will our old disk chisel shatter the hard pan better than an inline ripper?

Answer: You have to get below that hard pan. That puts you in the 13" minimum that you have to get down to. That can be hard for a disk chisel to do. You have to take out the hard pan, and bear in mind, you’ll probably only get a third of it out the first year. It could take you several passes over the next few years to get that hard pan out of there completely.

With vertical tillage you have to achieve complete shatter across the top. Whether you can get your chisel in that deep and get complete shatter is questionable. It requires a lot of horsepower to get the tool to the minimum depth you have to reach. For example, if you’re on 28" centers, then you need to get 14" deep at a minimum, and so forth. There are a number of different versions of disk chisels, and my guess is yours won’t reach that layer. If it does, then you’re probably OK.

For instance, if I had a Case IH 870 disk chisel and ran it 13" deep, and I could pull it, I could take that hard pan out over time. However, when you reach for a hard pan that’s at the furthest reach of your depth window, it will usually keep that chisel plow out. What happens is that tool will get down to the layer and then bounce on top of it. If you can’t get below the hard pan or pull the disk chisel, then you need to go to an inline ripper.

The deeper the hard pan, the more difficult it is to take it out. If it’s in the top 4" of your ground you can blow it out with a chisel plow, but down in that 13" range it can be tough. You may have to go with an inline ripper one year and then use a chisel plow to finish the ground.


Can My Soils Benefit from Pelleted Lime Applied through My Strip-till Unit?

Feb 22, 2013

Question: I am on a strip-till/no-till corn-soybean rotation in north-central Iowa. I've been putting down fertilizer for both crops in the strip-till pass. My most recent soil test shows the pH is getting to the 6.1-6.5 area and I'm concerned with fertilizer availability. With no tillage, lime wouldn't be worked into the soil and even if we decided to do shallow tillage on soybean stubble going to corn, it would not get at the lower soil levels where the fertilizer is placed by the strip-till coulters. My fertilizer dealer tells me that there is pelleted lime available that could be mixed with the dry fertilizer and placed through the air delivery system of the strip-till unit. Any comments or further ideas?

Answer: I would not advise this. When we think about liming a field because of its acidity we’re trying to flush out hydrogen. When we take a pH reading of the soil we are measuring hydrogen. When hydrogen gets high we have to flush it out with limestone. You want to think about hydrogen almost like you would a weed seed. Think about how thick some weeds like Palmer amaranth and waterhemp can get in a field. When you put an herbicide on you need to get it in contact with all those weeds so you get a uniform kill. If you knifed your herbicide on, just because you have the right amount of herbicide on per acre you wouldn’t kill many of those weeds. Where you knifed it on you’d have such a high concentration of herbicide you would have problems. Limestone is the same way. To neutralize acidity you have to put it on like paint. Uniform coverage is key.

Limestone moves through the soil about a half inch a year. It’s not like phosphorus that moves an inch in 20 years. Limestone, the carbonate, which is what you’re applying, will move about a half inch per year in most soils. So, you want to surface apply small amounts, say a 1 ton to 1.5 ton rate, for example, and you want to apply it fairly often, like three times over a six-year period. Bear in mind, this is an estimate—you need to use a soil test to make an accurate prediction.

That limestone will keep moving down through the soil profile as you’re applying it over time. We have guys who have no-tilled for 15 to 20 years and they don’t need to tear it up; they can manage the pH from the top. The problem is if you knife that lime down with a strip-till bar, when it starts to neutralize it will be present in a very high rate in that small area and will tie up your phosphorus and give you some efficiency problems with your fertility. In a high pH soil when we have too much calcium it ties up the phosphorus and gives us fits. If you put pelleted lime down with a strip-till bar you’ll have the same problem. Now, you are correct that where you’re putting fertilizer it is more acidic, especially if you’re putting nitrogen down, but that acidity will flush out or leech out to some extent.

When we worry about pH we worry more about pH from a microbial standpoint, not from a crop standpoint. Corn can handle acidity down into the lower fives without much trouble, but soil microbes can’t. You’re not liming to feed the corn crop, you’re liming to keep the soil pH in the neutral range so the microbes can do their thing. If we were just liming for the corn plant so you could pick up calcium, then you could knife it in the strip. But you’re putting on calcium carbonate to neutralize the soil. You’ve got to think about putting lime on like paint. So, in that essence I wouldn’t put pelleted lime in my strip-till machine and I also wouldn’t spread my lime with a manure spreader.


Read More

Give Your Soil a Physical Exam

New tools and tests provide benchmarks to measure progress as you improve the health of your soil.

In the 'Lime' Light

Correct acidity to create diverse microbial populations, which decompose residue and release soil nutrients.


Is Vertical Tillage My Best Tillage Option This Spring?

Feb 14, 2013

Question:  I’m thinking about going to vertical tillage this spring; is there anything I need to be thinking about before I do that?

Answer: Before you take that step, I’d encourage you and other farmers to evaluate any tillage you might have done last fall.  Because it was really dry, guys got into their fields with chisel plows and inline rippers and got a lot of tillage work done. Now, everyone is thinking about leveling things up this spring once they can get back into the field.  One thing we want to make sure everyone is comfortable with is did they do their fall tillage properly? A lot of interest and attention have been drawn to vertical tillage, and a lot of new tools are being sold out there to level up fields.  But you need to know that if you didn’t do your primary tillage properly last fall, you’re probably not going to get the results you want with vertical tillage this spring. As soon as you can get into your fields, dig where you ran your chisel plow or inline ripper to see whether you achieved good shatter from shank to shank.  If you didn’t get good shatter in between those shanks and you have some firm columns out there, maybe a vertical tillage leveling tool isn’t your best answer. Running a vertical tillage tool where you don’t have good shatter is not going to set you up for a good seedbed or uniform root growth, and you may have problems with the planter bouncing across the field as well. Instead, maybe you need to go out there with a field cultivator or a disk to get things leveled up.  Now, if you get out to your fields and find that you did get good shatter, then going to one of the new vertical tillage tools this spring is fine.


Straight Talk on Tillage

As the term vertical tillage becomes more mainstream, clarifying what makes a practice fit this system is key.


Key Steps in a Transition to Vertical Tillage

Ken Ferrie reminds farmers that vertical tillage is a system—not just one tool. Switching your tillage system can be a challenge, but using better management for your soil can lead to higher yields.


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