Avoiding Soil Compaction

While I hesitate to say we're in for a late planting year I think it's safe to say that it won't be starting early. Soils are wet and with the temperatures we're seeing, they're cold and drying conditions are not good. At least the early part of the ideal April 20 to May 10 ideal corn planting window is in jeopardy. While the silt loam soils which make up most of Boone County aren't particularly susceptible to compaction, getting in the fields when it's too wet, can still cause significant problems.

The best way to check if fields are dry enough to work is to take a handful of soil and ball it up in your hand. If it sticks together, it’s too wet. If it falls apart, things are probably OK. Make sure to also take some soil from below the surface, down to a foot deep and try this.

Soil compaction can result in a variety of problems. Uneven emergence and early growth rate variability can result in corn and soybeans displaying what I call a “roller-coaster” condition with uneven plant height in a field, particularly in end rows. Compacted soils have reduced water-holding capacity. Poor root system development may lead to nutrient uptake problems or, if the weather turns dry, drought stress. Particularly with corn, the stability of the plant may become a problem. Even if vertical compaction isn’t an issue, planting when it’s too wet can lead to “smearing” of soil in the furrow and sidewall compaction.

The corn roots on the left show compaction while those on the right are normal
If growing conditions are good, moderate compaction often won’t cause many problems. This was the case last year where, as corn planting continued to be delayed, some farmers chose to plant where a field was 80-90% ready and take their chances in wet areas. I saw quite a few fields where sections exhibited sidewall compaction but the weather stayed wet enough that the root system was able to break through the compacted areas. The only real impact I saw was that these areas were a little more susceptible to stalk rots late in the season but not enough to be a major problem. It’s difficult to get a handle on the precise impact of compaction in a given year.

The failure of the root slot to close is often an indicator of sidewall compaction

Farmers can use several strategies to reduce compaction. Some of these, such as no-till, increasing soil organic matter, using cover crops, and improving drainage are longer term in nature. I’ll focus on what farmers can do, other than waiting for soils to dry, to reduce spring compaction.

 

Corn seedling showing evidence of
sidewall compaction

One way to reduce compaction in field work is to decrease the weight over each individual axle as much as possible. Lowering tire pressure will increase the tire “footprint” and spread vehicle weight out over a larger surface area. Using radial instead of bias-ply tires has the same effect. Dual-axle rather than single-axle equipment can also help.

The use of tracked vehicles also helps spread weight out. The key is to have many rollers as weight is greatest under the rollers supporting the tracks.

It's obvious that reducing the number of tillage passes reduces compaction by having equipment run over a field less. However repeated tillage to the same depth can create a tilled surface layer and a layer of underlying dense till which can result in subsurface compaction. Quite often we see armers using a vertical tillage tool or other "light" tillage to loosen up the upper layer of soil so it dries out and warms more quickly. It accomplishes this but it can also result in a compaction layer a few inches beneath the surface.

The most important item to keep in mind is that while there is an ideal planting date for corn, this is only one piece of the yield puzzle, and far from the most important one. Weather conditions such as temperatures and rainfall are more important. Last year’s corn crop was one of the latest planted in history but Boone County Farmers had very good yields. Doing field work when soil conditions aren’t right or “mudding in” the crop can result in problems which may prevent you from being able to take advantage of favorable conditions during the growing season.

2013 Purdue Corn and Soybean Field Trials

I was in a meeting today where someone asked me if Purdue's Hybrid Corn and Soybean Trial results had been published. In the process of switching offices I never posted this information. This may be a bit late as many of you have likely already completed your seed orders however the following link is to the trial results:

2013 Purdue Corn and Soybean Performance Trial Results

Farm Drainage Program Report

The Clinton County Extension Service with support from the Clinton County Farm Bureau and Clinton County Soil and Water Conservation District hosted a program on August 8, 2013, "Farm Drainage for the Environment and for Profit."

This was a good program and we had about 50 people in attendance in the morning and a few more popped in for the afternoon (when PARP credit was offered). As usual, I had to perform my duties as host so I only caught about half of the programs but I'll report on what I have notes on.

Jane Frankenberger from the Purdue Ag Engineering Department opened with, "Making Farm Drainage Decisions." I don't have a lot of notes from this one as I was still scrambling around but the two items I did jot down were that in a long-term study they've been doing at the Southeast Purdue Ag Center (SEPAC) in Jennings County tile drainage at 66' spacings had shown basically the same yield response as tile spaced at either 33' or 16'. Another practice she's been working on is called Drainage Water Management. This document explains this far better than I can but basically a structure is installed within the tile system where you can close off the flow of water out of the tile and conserve water for use in the field. The item I noted for this is that each structure can control water for about 2' of field slope from where it's installed. Within that area the long-term yield impact ranges from 5.8% to 9.8% depending on which study you look at.

Clinton County Surveyor Dan Sheets was up next with "Clinton County Drainage Permitting." Dan talked about how any time a farmer ties into a county drainage structure, either field tile or an open ditch, you need to contact the Surveyor's office BEFORE you start work on the project. There is a permitting process and fee which is not too much and far less than the fine (and costs of possibly having to redo the system) if you do work without getting one. The Surveyor's Office would like to be notified when you're doing the work so they can inspect where it outlets into the county system and also so they can GPS it. The key points I took away is that they want you to use sub-mains and not make too many outlets into the county system. The big message is that county drainage is a public utility owned by the taxpayers and needs to be treated like any other public system.

The next speaker was Justin Schneider, formerly Staff Attorney and now Director of Public Policy for Indiana Farm Bureau speaking on, "Legal Aspects of Farm Drainage." I'm going to leave this alone as I simply don't have the space here to fully discuss it but if you're interested in one perspective, you can take a look at this paper by Gerald Harrison of the Purdue Ag Economics Department.

After lunch Eileen Kladivko of the Purdue Agronomy Department spoke on, "Tile Drainage and Nitrogen Management." In contrast to every other presentation, I have a full page of notes for this one so I'll hit a few highlights. Much of this presentation focused on studies Eileen has been involved with at SEPAC for an extended period of time. First, Nitrate is not lost from the system in July-September. The vast majority of it is lost from November through May. It's important to note that this is different from studies done farther North. For example, in Minnesota 100% of Nitrogen is lost in April-June as before this the ground is frozen and no water flows through field tile. This is not the case most years in Indiana.

The key variable here is the amount of water which flows through the tile. The concentration of Nitrogen in the water is the same whether it's a wet or dry year, just that in wet years the quantity of water is much greater so more N is lost. Also, in recent years they've been experimenting with cover crops and fields with cover crops show a reduction of 5-20 lbs per acre per year over fields without. Studies in Iowa show that cover crops reduced Nitrogen loss from about 45 lb/ac/yr to about 18. So cover crops do seem to help conserve Nitrogen.

Ben Reinhart from the Clinton County SWCD and Kerry Smith from Howard County NRCS gave the final presentation, "Tillage and Conservation Cropping Systems for Drainage, Fertility and Weed Control." This was another presentation where I took very few notes however Kerry did some demonstrations showing how effective cover crops and no-till are at reducing erosion. Ben's discussion was on some of the practices such as no-till and cover crops which increase water holding capacity of soil and may reduce the need for drainage.

I may not have taken many notes for this session but I did get a nice picture of Kerry Smith and two assistants (one is Tom McKinney, I didn't catch the name of the other gentleman) demonstrating soil erosion differences between no-till and conventionally tilled fields.

The final presenter for the day was myself talking about Pesticide Drift (this was different from what was on the agenda). My main point was that I've been receiving a fair amount of drift complaints in the office this year and farmers need to be willing to talk to their non-farmer neighbors. If you aren't and something happens, instead of calling you about it, their call might be to the State Chemist's.

I have a page up on our Extension Office website which includes PDF's of some of the presentations. I encourage you to take a look at them when you get the chance. Thanks again to Farm Bureau and the SWCD for their sponsorship of the program.

Farm Drainage Program Page

Soil Health Workshop

The Greater Wabash River RC&D will be sponsoring a Soil Health Workshop on Thursday, March 1. The workshop will be held at the Beck Center at the Purdue Agronomy Center for Research and Education on US 52 in West Lafayette. The two main areas of focus for the day will be on cover crops and drainage, including field tile.

This Workshop is being held immediately following a meeting of the Midwest Cover Crops Council on February 28 and 29. For a detailed agenda and registration information, go to the MWCC web page. A brochure and registration form is on that page. There is also a detailed agenda. You can register for the entire three days or plan on just attending for one. The registration deadline is February 14.

Fall Tillage Advice

Now that harvest is nearing completion folks will start thinking about preparing for next year. Every year I see a fair amount of what I would call "recreational tillage" going on. Sometimes fall tillage is desirable and even necessary, however I encourage you to consider the costs and benefits before firing up the tractor.

Tony Vyn from Purdue Agronomy has a very good article in Ag Answers on areas to consider in making tillage decisions. I encourage you to take a look at it.

Tony Vyn article from Ag Answers.

Cover Crops

Fair is coming up and I haven't had time to post much on this blog over the last couple of weeks, and likely won't have much time until after the fair ends.

I haven't heard of a lot of prevented planting acres in Clinton County but I'm sure there are some. An option which has some benefits for helping your productivity is to plant a cover crop. Eileen Kladivko of Purdue's Agronomy Department and Barry Fisher from NRCS have an article on this in the latest issue of Purdue's Pest and Crop Newsletter.

Keep in mind you can't hay, graze, etc., cover crops on prevented planting acres.