No-Till Farmer Blog

I thought I would follow up on my nutrient management session at the National No-Tillage Conference in Cincinnati a few weeks ago.

This session had a lot of interest and questions, and the time got short, even though discussion followed for over an hour in the hallway afterwards.

With commodity prices and input costs, much more emphasis will be on doing the right thing with nutrients and application. This includes applying them in a way where they are not subject to loss and available for crop uptake. These nutrients are part of the “equity” of whoever owns and manages the land, and the grower that manages them properly will not only be more profitable in the short term, but will be building value in the soil they farm.

All soil is not created equal just because it is the same soil type. The condition of the soil can mean a vast difference in profitability — including not only the chemical, but also the physical and biological components of the soil.

Many times the chemical properties are managed the most because they’re the easiest to control.

But as crop values and inputs increase, the actual impact from the chemical (nutrient) side is reduced in proportion to the physical and biological properties of the soil.

The soil condition is the OPERATING SYSTEM for the crop, and determines the efficiency and recovery of nutrients from the soil. You can have a fantastic inventory of P and K on a soil test, and a poor operating system, and recovery by the crop will be inefficient and expensive.

On the other hand, if the soil condition is such that roots grow easily, soil microbial life thrives, water and air move freely through the soil, and beneficial chemical reactions occur with ease and frequently. A soil test that shows marginal P and K levels can easily out-yield a similar field with high levels of nutrients, and the profit difference is tremendous.

We’ve been led to believe that as long as your pH, P and K are within given ranges, and you apply calculated amounts of nitrogen when needed, everything will be fine.
Agronomy for today’s farmer is much more complicated than that. RECOVERY of those nutrients is much more important than the actual levels shown on a soil test, and our research plots prove that.

A soil that has good structure, ample microbial life, and a decent water infiltration rate (remember that air follows water into the soil as the water moves through it) needs less nutrients on paper than a soil with lesser structure and biological activity. Stress on the crop is much less in the good soil structure; stress from too wet, too dry, heat and cold, herbicides, insects, and disease. These stresses compound upon each other, and methodically reduce the yield potential of the crop.

You can help create this optimum soil structure condition by paying attention to the calcium/magnesium relationship in the soil, if you have marginal internal drainage and significant clay content in your soil.

Although both elements have the ability to purge hydrogen from the soil colloid and create an acceptable pH, their reactions with clay are quite different. Calcium has a flocculating property that supports good soil structure.  Magnesium, much smaller than Ca, can “peptize” with clay particles and cause a sealing effect that makes water movement tough in the soil.

A word of caution: lower-exchange soils that don’t contain a significant amount of clay should not be managed in this way, as Magnesium is not a soil structure component in those soils, and is necessary in levels that support crop uptake without deficiencies.

Other management techniques that enhance the physical and biological properties in the soil are tillage that improves soil structure, and lack of tillage that reduces soil structure. Tillage usually breeds tillage, so be careful to ensure you are, in fact, improving the soil structure.  Avoidance of compaction, proper planting without sidewall compaction, residue management, efficient nitrogen management, and use of cover crops should all be considered.

Over the last several years, our nitrogen plots have strongly supported this recovery enhancement in optimum soil-structure conditions. High-yielding zones are requiring much less nitrogen than low-yielding zones, and the difference is soil structure and recoverability.

Nitrogen is an easy nutrient to evaluate on this basis, because it isn’t stored in the soil to the extent of P and K.

We can evaluate applied rates to economic return in the year of application. We’ve shown that soils with an optimum calcium/magnesium relationship can produce corn at a rate of near .5 pounds N per bushel, while those soils with adverse Ca/Mg conditions may take as much as 2 pounds of N  per bushel.

This makes a big difference to the bottom line. We were tipped off on this years ago by our consultant friends in the sports turf industry.

You also need to pay close attention to the timing of your nutrient application. We ask these crop inputs to be soluble in the soil so the crop has a good chance of recovering them. You can’t ask them to wait until planting time to become soluble, it doesn’t work like that.

I believe the timing and method of application have much more to do with off-site movement of nutrients than the actual rate applied. When I make a recommendation for nutrients, the only consideration is what the crop will need.  We need to make sure those nutrients are properly applied.

If there’s a likelihood of off-target movement, don’t do it.  Applying to snow-covered, frozen ground is a recipe for economic loss. You may find yourself replacing those lost nutrients at a price twice their cost. If a soil is well balanced and managed, a grower can skip a year of P and K and apply them at a time when we know they will become part of the soil. This also allows for purchasing nutrients on “down cycles” with the great commodity swings we are seeing.

Blanket application of nutrients and guessing without a representative soil test are fast becoming a thing of the past.

The profit potential of VRT applications of lime and fertilizer is greater today than ever, and enhancing your soils’ recovery rates will put much more profit in your operation.

And fortunately, enhanced recovery of nutrients is the solution to water impairment and environmental stewardship for agriculture.

Ohio and Indiana have been hit hard and often with rain this growing season. Many fields have just been planted in the last week or two, some remain unplanted and prevented planting is being taken on many fields.

At my office we have received more than 17 inches of rain since April 22, and had 27 days with measurable rain in that 67-day period. That’s leading to tough conditions to get a crop planted properly, and then a rough road for those crops that are in the ground.

An observation from this spring is that no-till corn fields that were planted and have good soil balance are in much better condition than the conventionally tilled fields. The exceptions are those fields that contain a high level of magnesium in relationship to calcium. Those fields don’t have the soil structure and internal drainage of fields where the farmer has paid attention to the calcium and magnesium levels and has applied lime.

The tilled fields also have been hit harder by excess water. Precious soil aggregates were destroyed in the tillage process, and many times a layer was put in the soil that inhibits the movement of water and air.

We have been so wet for so long that many of these fields have gone anaerobic, such as the one in the photo. With poor soil structure, there are no air pockets and channels for the soil life to hide and survive.

We have noticed the hair roots disappearing in these fields. Without those tiny roots, the plant can’t take up nutrients. Farmers are looking at foliar feeding these stressed fields — if they can get dry enough to apply — but I have little faith that will change anything. The real problem is with the roots and the poor soil condition.

The calcium-magnesium relationship that has been well-managed shines in a year like this. Soil microbial populations are much higher under no-till with good soil balance, and can handle longer periods of water stress and recover quickly. The soils where magnesium hinders water infiltration (soils with clay content) lose microbial populations fast and recover extremely slow.

All these organisms are important for nutrient uptake in the plant and development of new plant tissue. They are the key to successfully handling weather stress. No-till fields that are well-balanced with nutrients, as well as calcium and magnesium, provide a great environment for soil microbes and that optimum “live” soil. They are definitely more profitable to farm and can relieve a lot of “farmer stress” in weather patterns like we are experiencing this year.

Baseline fertility recommendations have been around for years and have stayed the same over time. Keep a certain pH; 1.2 pounds nitrogen per bushel for corn; ranges of phosphorus and potassium that are considered low, medium or high by looking at the number on a soil test; and “removal rates” based on element levels per bushel.

Many of these needs were based on “efficiency factors” that may have estimated your crop could find 70% of available nitrogen, 30% of available phosphorus and 40% of available potassium.

These were decent recommendations for their time, but very general in nature, and led to blanket applications of nutrients that could mean overapplication based on unrealistic yield goals and non-representative soil tests. Over the years, farmers got the impression that more fertilizer equaled more yield potential.

Fast forward to 2010. Things have changed in a hurry in agriculture. Many of the input costs have increased by two to 10 times. Equipment has gotten much better, especially planters. Hybrids and varieties have many advances, and seed treatments, along with the planter improvements, have made near-perfect stands possible.

Weed-control options are many, so competition for nutrients should not be a problem. GPS has brought evaluation tools to field level for every farmer that wants to learn. You can now know more about your own performance than ever before and make better decisions for nutrient management.

Let’s talk a little bit about soil testing. This is an excellent tool with many uses, but widely misunderstood. When grid sampling came out in the 1980’s, it was thought to be state of the art. (This was before invention of the yield monitor.) The good part of grid sampling was it got farmers to soil test. Many were doing very little testing at the time, and what was done was not representative, perhaps one sample for 40 acres.

One bad point of grid sampling was that it preceded digitized soil surveys, so it ignored soil types. It cost a lot of money to sample on 2.5-acre grids, so most farmers were asked to live off that one test for 5 years, a risky move with fertilizer dollars.

This system ignores two of the most important elements of a representative soil test: The farmer and the local agronomist or CCA. No one gets asked where to sample except the computer. Give it a boundary and it will tell you where to drive the ATV to for sample No. 1.

And once the ATV is parked, the sampler takes five or six samples, puts it in a bag and sends it to the lab. The lab runs the analysis and magically, when returned to the software, those results now represent a 2.5-acre grid.

But, was that grid adequately represented? No! A 10-by-10-foot area was sampled, and there are 1,090 of those in 2.5 acres. And then, besides being non-representative, variable-rate nutrients and lime are applied, creating more variability than was present to begin with — depending on the mathematical equations chosen in the software.

This type of nutrient management was widely used as a marketing program by fertilizer dealers to differentiate them from their competition, justify variable-rate technology equipment and develop another business enterprise. Could variability be shown? You bet! Could the products be varied? You bet! Could results be analyzed and best management practices that were more economically and environmentally sound be established? No. Another case of “more is considered better.”

Now, let’s look at the actual soil test. Guidelines assumed all soil tests are created equal, and they are not. Ten different labs can give 10 different results, depending on the methodology used at the laboratory. Not wrong, but different. The challenge for the agronomist and CCA is to correlate consistent lab data, from well-represented samples, to crop growth.  But, it’s extremely difficult to compare one lab’s results to another.

The most variability probably comes at the field level and the person pulling the sample. Close-core inspection, so the area sampled is representative, is a must. You can mix two soil types together in the same bag and the lab will return an analysis to you, but it may well represent something that is not even present in your field. You make an application based on it, get no results and create variability.

I’ve also seen samples taken by people that didn’t realize the depth needed to be strictly controlled at 6.67 inches, unless otherwise directed to the laboratory. Analysis equipment only can measure parts per million, and the industry assumes one acre of soil 6.67 inches deep weighs 2 million pounds, thus the “pounds-per-acre” figure on the test.

Does it really mean pounds per acre? No, it’s just a number to correlate to crop growth. If the sample depth is anything different than 6.67 inches, and not noted to the lab, poor representation results.

Good representative soil samples on a regular basis — at least every other year — can help you build a good database. This will allow you to verify the accuracy of your tests, and enable good fertility and lime recommendations.

I’d suggest you use a laboratory that participates in the North American Proficiency Testing Program. These laboratories are checked for accuracy regularly and scored accordingly. If the lab you use doesn’t participate in the independent rating program, ask them why not.

Huge dollars in the farmer’s budget are riding on sound fertility recommendations every year. Those recommendations are also the key to environmental stewardship.

There are many available tools to aid production agriculture, with most utilizing some sort of technology. But I think one of the most valuable tools for me, as an agronomist, is a well-calibrated yield map.

Using a yield map to develop high-, medium- and low-yielding management zones will pay great dividends, and disburse those dividends quickly.

Management zones are the blueprints for managing nutrients for profit, as well as for environmental stewardship. Once these zones are established, they will repeat through various weather cycles, sometimes alternating between high and low yield, but usually still represented.

Yield zones are a better depiction of the soil types in your fields rather than a digitized soils map. The soil survey says one soil type is present on one side of the line, and another soil type on the other side.

This is not how it happens at field level. There are actually transition zones as one soil type blends into another, and good yield maps will show these areas. These areas will need to be managed differently.

More than likely, with today’s progressive farmers, fertility will not be the limiting factor or the reason yields vary within a field. Water infiltration and drainage is probably the No. 1 factor, and it’s good to know if that’s a problem in your fields.

If it’s a problem, you can decide if it can be improved or if you can manage it more economically than with a “blanket” fertility approach.

The next most limiting factor I see is lime. Management by yield zones has helped me fine tune lime applications better than any other evaluation of the soils.

Lime is the “operating system” of nutrient management, similar to the operating system in your computer. You may be able to squeak by with an out-dated system, but operation will be sluggish and efficiency poor. Lime is like good oil in the crankcase, essential for top performance.

With today’s costs of nitrogen, phosphorus and potassium, you really need the soil to operate efficiently.

Are you getting 60% effectiveness from your applied phosphorus, or just 30%? Does your crop find 25% of the potassium in your soil, or are you in the fast lane to profitability with a 70% capture rate? Can you produce a root system that recovers 90% of the nitrogen available to it, or does it struggle by only utilizing 40%?

Not only does lime create the environment for optimum chemical reactions that are beneficial to nutrient uptake, it also affects soil structure and microbial life by creating a desirable “live soil.”

Depending on your soil composition, calcium and magnesium can have a profound effect on water infiltration rates. Does water run in, or run off? Does soil life thrive after rain, or does it take a step backward due to poor infiltration of water and, in turn, poor air movement into and out of the soil?

Do nutrients tie up after a rain, or in the case of nitrogen become lost forever? Or is your crop able to keep on pace and capture the nutrients it needs, even under stressful weather conditions?

Soil science is complicated and is not a one-size-fits-all program. Yield monitors and in-field plots are helping us prove new practices for agriculture on a farm-by-farm basis.

Farmers need to think outside the box today and not accept Agronomy 101 rules just because that’s the way it was done 30 years ago. Things have changed. There’s a lot at risk and a “prove-it” approach is well warranted.

My next post will dig deeper into this subject and focus more on precision ag tools, so stay tuned.