A series in which we answer questions about specific aspects of our program
Once the soil is properly corrected in terms of the needed fertility levels, is there any good reason to keep testing the soil every year?
Due to the nature of our business it would be to our benefit when someone decides to have us do another set of soil samples and recommendations for them! So for some it may be easy to assume that any further answer given to such a question would simply be geared toward that end! But keeping in mind that our job is to be that of an advisor, and the client is the manager, perhaps some of the information presented here will help in that regard.
The Soil Nutrient Needs to be Maintained
It seems that far too many people get the idea that when a soil is correctly balanced with all the needed nutrients, it will then be many years before it needs more than a routine maintenance in terms of fertility levels. This is not the case for any productive soil, especially when you want to achieve top quality and excellent yields.
As nutrient uptake and yields improve, more of all the elements required for growth of that crop will be taken up. If these losses are not measured and replaced, production capabilities will decrease even more quickly than would previously have been the case because more is needed and removed as yields and quality increase.
Many involved with soil fertility suggest taking a soil sample every three or four years. If all that is being sought is a very generalized direction then this time frame is at least better than none at all. But in order to achieve the utmost from a soil, it should be analyzed and amended where required prior to every major crop to be grown there. This is true even if your last soil test on the field showed fertility levels to be excellent.
A Result of Neglecting to Soil Test
One client who grew cotton was amazed that we could tell him, from the soil samples, a particular out-of-the-way field was one of the best he had. The next year he decided to retire and wanted to wait until the farmer signed a lease before taking soil samples again. Though intentions were good, four years of crops were grown on this land before it was re-tested. This same field that tested as one of the best five years earlier now tested to be one of the worst.
Again the owner was amazed that we could correctly tell him this based purely on the soil samples taken. The field went from one of his best to one of his worst in five years! This is not an isolated case. The soil which produces the most loses the most, especially if what is harvested is taken elsewhere.
A cattleman who grew his own pasture and hay expressed it well when he pointed out that just making the equivalent of one extra bale of hay per acre would more than pay for the cost of soil testing. And another farmer once confided that if he applied just one nutrient that he did not need in order to make a crop, the cost to him is far greater than that of a soil test. Perhaps even more important is the loss in yield by failing to identify a nutrient deficiency that has hurt the crop, that would have shown up if the soil had been tested.
Leaching of Nutrients
All of agriculture recognizes the need for moisture in some form, generally rain or irrigation water, in order to make a good crop. But it is also recognized that these same sources of moisture can deplete the soil of both needed and unneeded elements.
For example, when used correctly, gypsum (calcium sulfate) or other forms of sulfur materials, can help leach out excess salts, particularly sodium. However, after the problem is corrected if you continue to use sulfur or sulfates to excess it will result in removing additional nutrients that should be conserved for growing the next crop.
Also, too few consider that an excess of nitrogen, once it has converted to nitrate nitrogen and can be leached downward through the soil, can also result in forming nitric acid, which will deplete calcium from the soil as it moves with the groundwater. In addition, high bicarbonates in well water may cause calcium to be stripped from the soil thus lowering the pH and reducing the uptake of nutrients required for optimum fertilizer utilization, whether supplied from commercial fertilizers or composts and manures.
An Annual Soil Test Aids Good Nutrient Balance
A good soil test every year helps identify these conditions and avoids their possibly damaging effects. It is a mistake not to take soil samples properly and use them for the benefit of the soils and the crops to be grown there.
What would you recommend, based on the type of soil testing you do, for making the highest yield of corn possible on my field?
First of all, take the needed soil tests far enough ahead of time to be sure there is sufficient time to receive and consider fertilizer and soil amendment recommendations, locate the required materials, and apply them in a timely manner.
Timing the Soil Sampling, Fertilizer Application
For liming materials and trace elements such as iron, manganese or copper: if you intend planting corn in the spring, plan to apply these materials the previous autumn for best response from the crop.
Before corn is hip-high in the spring, is generally considered the time to sample in order to see soil fertility levels at their best. (Provided that the soil is not drought stressed, that large amounts of sulfur have not been applied in the last two to six months, and that sampling avoids areas where nitrogen has been knifed in, or recently broadcast in large amounts. Because any of these situations could significantly lower the soil pH and make it appear that lime is needed when such is not the case.) Otherwise, to see soils at the lowest fertility levels sample as soon after harvest as possible where drought is not a factor.
We count on each sample received as having been taken to correctly represent the area being tested. (To assure soil testing is correctly achieved please see the instructions on taking a good soil sample). That being the case, the more completely you inform us about conditions for the corn (or any other crop) you will be raising, the previous crop including yield, and the fertilizers previously applied, the better we can advise concerning needed soil amendments and fertilizers.
To grow corn, nitrogen is usually the biggest question in regard to fertilization, and the most difficult recommendation to correctly determine. So in order to properly consider nitrogen needs, several questions need to be answered. For example, what should be a reasonably expected yield goal? Fertilizing for each field's average yield plus 10% is usually a prudent goal to set. Instead, too many corn growers just apply an excess of nitrogen to assure there is an ample supply, because "it requires such a small increase in yield to pay for it."
Keep in mind that an excellent soil only requires one lb. of nitrogen (including N from humus) for each bushel of corn produced. But poorer soils will require up to one and a half pounds of nitrogen per bushel of corn. Any farmer who consistently applies more than one and a half pounds of N per bushel of corn, including N from humus, legumes, manure and carryover from the previous crop, is likely to be hurting soil fertility and nutrient uptake in relation to calcium, copper, and perhaps even sulfur.
Such overuses will most likely not result in a reduction of yield that same year, so producers that overuse nitrogen are slowly blind-sided as a result. When average corn yields begin dropping don't just blame "the weather", check fertility levels too! Failing to build correct soil fertility can easily cost corn growers 20-40 bushels of potential yield.
Other Information That Helps Us Provide the Best Recommendations
Yield can vary widely due to climate, especially moisture availability, so we have to rely on those sending the soil samples to give the proper potential yield information..
Irrigation In some areas all corn is irrigated, in other areas none. We need to know if the land is irrigated because it can influence the amount of nitrogen, sulfur and boron recommended
Type of corn Be sure to state as clearly as possible the type of corn you intend to grow. When a sample lists the crop as "corn", unless stated otherwise it is taken to be corn for grain, not silage corn, sweet corn, seed corn, or popcorn, which could require quite different recommendations.
It also matters whether you will be raising 90-day up to 110-120 day corn. 90-day corn needs the bulk of its nitrogen early in the season. But 110-120 day corn needs adequte nitrogen and sulfur over a longer period of time. When not specified, 110-120 day corn for grain will be the default used for making fertilizer recommendations, since it is more widely grown in the areas from which we receive the most samples.
Fertilizers available to you Be sure to list the fertilizers that are available for use in your area. Most certainly nitrogen materials will be available, but which types are easiest to obtain? The grower needs to tell us. The same goes for phosphate and potassium. Also list any liming that has been done in the past three years as that can affect nutrient availability - and possibly change both the amount and type of lime presently shown to be still needed for the soil.
Finally, the type of fertility program the grower wants to pursue should be stated. Most growers choose the 'excellent' program. But unless your corn is already producing top yields, when the costs to provide excellent yields and quality are calculated, for most growers it is too expensive. Better to begin with a 'building' program or 'maintenance' program and stick with it for at least three years. When fertilizer prices are high, commodity prices are low, of financing is limited, then consider the minimum program for crop production in terms of fertility for a year or two under such circumstances.
Perhaps this will help explain why it is important for you to inform us about more than the fact that corn will be planted on the areas where soil tests have been taken and for which recommendations have been requested. Just keep in mind, the information you provide along with the soil sample is a key factor in determining the best fertilizer program to achieve the best yield of corn.
The first point to remember when considering this question is that every soil has different characteristics; every soil has a specific capacity to hold each of the elements supplied by any liming material.
Soil Nutrient-Holding Capacity
This capacity is determined by the amount of clay and humus contained in each soil, these being the only portions of any soil that will attract and hold plant nutrients. Once this nutrient- holding capacity is reached, using more of any material containing the element that is already at optimum level will only result in driving off or tying up some other nutrient that should be there and available for use by plants growing in that soil.
Therefore, the capacity of every soil is limited when it comes to attracting and holding calcium and magnesium, the principal elements from limestone. They can help when needed, or hurt when prudent levels are exceeded! Calcium from gypsum can also be very helpful in adequate amounts, but detrimental if the sulfur or the calcium it contains is enough to cause excess thus reducing the availability of other needed nutrients
Misunderstandings concerning whether it is possible to use too much lime continue to exist because of the assumption that if you can apply large amounts of lime on one or more soils somewhere in the world, then all the rest of the soils in the world can stand that much lime too! This is not correct! It can be very costly to the farmer or grower who fails to accurately measure what is there already, whether more is needed, and whether or not any other needed nutrients will be adversely affected if liming is done.
Potential Damage Caught In Time
As an example, a cabbage consultant had us test some soils. He was using high calcium limestone on high pH soils to avoid club root problems. He had extremely heavy clay soils with large nutrient-holding capacities. In the previous 7-10 years, before using our services, he had applied a total of 14 tons per acre of high calcium limestone. His crops had continued to improve.
From our soil analysis we found that all that lime had added just enough calcium to reach the ideal required for his soil. The soils here were so rich that all the other elements were also still there in adequate amounts, so there was no damage due to nutrient tie-up from the large amount of lime applied up to that point.
But now, as the tests showed, his land was to the point that using additional lime, even at one ton per acre, would begin to cause nutrient deficiencies and result in yield reductions. If he just kept on doing what he had been, even though it had "always" provided better crops, his results would now begin going the other way. Simply assuming that lime should be added for the next crop because it worked on the previous one can be a serious and costly mistake.
So yes, this grower's soil survived and prospered by receiving 14 tons of lime over a period of less than 10 years, but this is usually not the case; most land would suffer losses long before that.
For example, another client - a neighbor to the client we have just mentioned - needed no high-calcium lime at all on his soils, had never applied any, and had no problem with club root in his cabbage fields, with a pH below 7.0. To do what his neighbor did would have been costly to apply and detrimental to his crops because his soils were entirely different in terms of fertility needs. Adding lime just because it worked for a neighbor, or even for another area on the same farm, can be a serious and costly mistake.
A Result of Excess Lime
Another company hired us to sample and analyze just over 2,000 acres. They had begun having problems with low yields in the past few years. Once the soil test results were examined the problem was obvious. The soils had received so much lime it had severly reduced the capacity to attract and hold enough potassium and caused manganese and zinc deficiences in the fields that barely had enough even before the lime was applied.
Someone had convinced the owners that you could never apply too much lime. They had applied 6 tons per acre four years previously. Yields went up the first year, but then dropped thereafter. Only one field had not received the lime. Fertitlity there was the best on the farm. All other fields had dropped from 45-50 bushels to 25-30 bushels per acre soybeans - a crop that tends to benefit greatly from adequate liming. Even with soybeans, too much lime is a detriment.
Too Much Lime May Inhibit Other Nutrients
Normally, applying lime will at least somewhat limit other essential nutrients needed by the plants to be grown there, and the grower had better know whether this is the case before using significant amounts of lime. When such is the case, the grower should be told that and also what will have to be done in order to avert the problem. Just knowing the pH will not tell the grower or his consultant this essential information.
To correctly make this type of determination concerning whether liming will help or hurt the soil, a soil test must provide extremely accurate information.
In addition to showing what levels are there, to be useful a soil test must also show what level should be present and if there will be too much or too little of any other element once the liming is completed. This includes the levels of magnesium, potassium, boron, iron, copper, manganese, and zinc. If any of these are present in borderline amounts, failing to measure and determine that this is the case and what to do to remedy the situation if lime is used, can reduce yields even when lime is required and correctly applied, but especially when it is used to excess.
You can use too much lime. And although we have mentioned some successful large applications that are the exception and not the rule, keep in mind that some sandy soils would receive too much lime at a rate of one ton per acre. The key to liming is to measure what the soil requires, supply that need as soon as it can be feasibly done, and apply only what is needed to do the job properly.
See also our article The Dangers of Too Much Lime".
Yes, we are. We gladly work with soil samples from gardens of any type. And in fact, we have made recommendations for hundreds of organic gardens within the past twelve months. But there are some considerations that should be made before you send a sample to us for analysis and recommendations.
Take Time to Sample the Soil Correctly
First, if you do not regularly take soil samples, be sure to review the guidelines in Hands-On Agronomy (see also our Soil Analysis page). The recommendations we make can only be as good as the sample that has been taken for analysis. Too many people make mistakes in the way they take soil samples, that wind up costing them in terms of what could have been accomplished from the soil test they took and sent for an analysis.
Some common examples include taking the sample too deep, combining different types of soil - like sandy areas with clay areas, or red clay combined with yellow clay - into one composite sample, or applying materials such as lime to the soil without keeping a record of how much and when it was applied. It generally takes three years for lime to completely break down and there is no way of telling what will be the actual effects without that information.
When to Take Samples
If you take samples in the spring we recommend taking them before you fertilize your soil. If you have fertilized already then wait for at least 30 days, or 2 good rains or irrigations - whichever is longer - and consider the next two points before taking more samples. That is because any recent applications of nitrogen (generally within the last 30 days), or moderate to large amounts of sulfur (generally 60 - 180 days) can skew the test results making it appear there is less calcium and magnesium in the soil than is actually the case. That may then show a false need for lime that is not really needed and likely should not be added.
Once taken and prepared as shown below, send the sample on to us for analysis and recommendations to supply timely treatments each fall or just after the harvest is completed.
This will give time to locate any materials that may be needed and get them applied in the autumn to prepare for the next spring crop. Keep in mind that any depleted nutrients did not happen in just one year, and correcting them in the proper manner will not likely happen in one year either.
Be sure to fill out a soil submission form. If you need results quickly, once you have checked with us as to how long a recommendation from us will take, and determined that the wait is worth it, be sure to also request a copy of our soil submission form (available at no charge by fax, US Mail, or click here for a printable copy) and fill it out as completely as possible. This will enable us to get your results completed much faster and back into your hands with the best possible recommendations.
Let us know you are organic. Be sure, if you are an organic gardener, that you point this out to us so we can take that into account when making recommendations. Our soil submission form has a box that should be checked if you want organic recommendations. We also work with many conventional gardeners who expect to use the normal commercial products available locally, and we have no way of knowing you grow organically unless you tell us.
Allow Sufficient Time for Analysis
Just be sure to plan ahead and send samples well beforehand. If you need the information back quickly, it is not a good idea to send samples to us without checking to see how long it is likely to take. Even then, it is only our best estimate because of late the volume of samples has at times far exceeded our best estimations.
Some misunderstand what our soil test and evaluation is all about. Every test is carefully considered on an individual basis and recommendations are based on the specific needs of the soil, what is to be grown and the fertility program you select. This requires much more time per sample than for one where just sending out the number of pounds of N-P-K to feed the plants and a lime recommendation based solely on the soil pH is provided!
We want to help our clients achieve excellent production and the top nutrient levels for the soil and everything they grow on it. Those who know us best understand that this is not just what we say, but it is our commitment. It will take longer to get the recommendations to you, but it is the only way we know to do it properly. However, if you are looking for a quick answer, or feel you need samples back in a hurry and we cannot meet your deadline, then by checking with us before sending the samples you would still be able to consider sending them to another lab who could better meet your needs.
Sources For Fertilizer
Please note we do not sell fertilizer and expect that you have, or are willing to find, the necessary products to supply what is needed for use on your property. Our soil submission form has a box in the lower right corner for the grower to list any specific materials they have available for use. If these will do the job we will use them in making the recommendations for your soil. Because of wide variations in make-up, just stating you have manure or compost without an analysis is not sufficient for us to be able to recommend its use. Without such an analysis, we will do our best to recommend any other correct materials to supply what is needed for that soil. It is generally possible to find sources for these materials by checking locally or on the Internet.
A consultant I know and respect says using the Albrecht system of soil testing has actually caused problems for one of his clients, and he recommends staying away from it. If the program really works as well as you say, how could something such as this happen?
There are several possibilities that come to mind when I hear of statements such as this made by a consultant, or perhaps even a farmer or grower who has suffered a loss while trying what he is told is the Albrecht program for soil fertility.
Was the Soil Test Truly Albrecht?
First in my mind is the question of the validity of the soil test itself. Anyone can say they are using the Albrecht system of soil testing. There are many tests that make such claims simply because they use cation exchange capacity and base saturation percentages on the test they have determined to use for making fertility recommendations. But as we have found over the years, the measured calcium, magnesium, potassium and sodium figures can be quite different from one lab to another.
Take calcium as an example. On the test we use, a medium to heavy soil should have around a 68% base saturation of calcium for maximum benefit. But when the figures on the test we use is 68%, some soil labs, testing the same soil, have shown closer to 60%, others 75%, and some even 80%. Which one is right?
In measuring magnesium, when the ideal of 12% shows on our test, in our experience some labs may test as low as 8% on the same soil, while still calling for 10-20% magnesium as the proper range on their test.
On a medium to heavy soil, when magnesium rises above 12% it is already causing the soil's fertility requirements - and depending on the crop, also the yield - to suffer. So if someone is growing corn there, and the magnesium is at 12% on our test, with calcium at 68% as stated above, it requires 1 lb. of nitrogen to produce a bushel of corn. But if the magnesium is raised by just 2%, it now requires 1.25 lbs of nitrogen to grow each bushel of corn. On the other test results mentioned in the preceding paragraph, which was being used by another consultant claiming to follow the Albrecht system, if the farmer raises the magnesium to the recommended minimum of 10% as reflected on that test, he is actually pushing it too high for maximum nitrogen efficiency. This would also reduce the yield of soybeans or alfalfa on that soil. So again, how do you know what answer is right?
Test Your Soil Tester!
Sometimes the soil test has been correctly performed, but the person doing the interpretation does not really understand what the test actually shows as needing to be done. Making incorrect fertilizer recommendations can cause even the best fertility program to look bad.
One good way to find out who can help you is to first determine what the numbers are supposed to be on the soil test for best results. Then sample an area that consistently produces well, and one that consistently does poorly, and - without identifying which is the 'good' soil and which the 'poor' - ask the consultant to choose which is which, and explain why.
Follow Through With the Program
Another possibility is that the farmer just partially followed the program, and as a result it makes the program look bad to those who are observing from a distance. Even when the Albrecht system is correctly employed, it can require as much as three years of correctly following the recommendations to begin to see the greatest benefits. To prove the program for yourself, choose an area large enough to justify buying and spreading the fertilizer and soil amendments needed, but small enough to budget for follow-through on all that the soil test shows to be needed, for three full years.
If someone tries to tell you that the Albrecht system does not work, first find out if they are judging it based on only one year of results. If a soil has not been receiving the needed nutrients in correct amounts for several years, correction will likely take longer than one year. It may happen in less time, but typically it takes three years to get the soil into good shape.
Next consider whether the person doing the recommendation understands what the soil test actually is showing needs to be done. Can the consultant consistently determine the good from the bad by just looking at the soil test results? If not, how could they really understand how to use the Albrecht system correctly in the field?
And finally consider the soil test numbers themselves. But keep in mind: the numbers do not have to match everyone else's numbers; the big test is whether the consultant knows what the numbers mean in the context of that particular lab's tests well enough to get the best results in the field.
We find the greatest challenge to the use of the Albrecht system is that of helping the farmer or grower verify for himself that all the nutrients that are shown to be missing, when provided correctly, will result in the best yields and quality.
It is not our goal to get people to send us soil tests, but to convince them to begin in a fashion that will allow at least a test of three years duration. It is not necessary to take our word, or the word of anyone else, when you have proven it to yourself right on your own soils.
The first thing to do is to determine for sure that high sodium is actually a problem. This may sound strange, but some growers we have worked with have assumed the sodium in their soil was high when that was actually not the case at all. Most people believe that when the soil has a very high pH it is because there is a sodium problem. But this is not always the case.
Elements Other Than Sodium Can Cause High pH
It is true that most soils with a very high pH have high to excessive sodium levels. But there are soils that have such excessive amounts of magnesium and/or potassium that are actually causing the problem, yet sodium receives the blame.
The only way to know for sure if sodium is a problem is by measuring the actual amounts of it,along with calcium, magnesium and potassium, in order to understand which of them is adversely affecting the pH level in each soil. Every soil has a specific need for each of these elements based on the nutrient-holding capacity of that particular soil. This can always be accurately determined when a soil test is correctly pulled and sent to be analyzed.
No Two Labs Provide the Same Analysis
The prevailing opinion in soil fertility management today is that one soil test is not that different from another and each will provide enough of the correct information to make an informed decision.
Before you accept that as fact, perform your own test. Using two sample bags, take side-by-side cores of soil from at least 5 different places in a given area of uniform soil fertility (see Taking a Good Soil Sample). Send one to us and one to another lab that you decide would be a good one. Ask for an analysis plus recommendations from each one. Take note of how different the analysis and recommendations are by comparison. It is not our intent to be different, but it is our intent to give correct advice.
Test Your Soil-Tester! The only way you may know for sure who is right is by setting aside land on which you do both programs for three years to see which one makes the most difference. For an accurate determination be sure to correctly follow through and do all that is recommended for that particular soil.
If Sodium Is In Excess
After it is determined that too much sodium is actually the problem, it should next be determined what the soil is actually lacking, before the proper corrective action can be taken. The best way to solve an excess of something in the soil is by supplying any necessary amounts of those elements that are deficient, the excess will tend to be automatically reduced.
Check Calcium levels! The next consideration should be whether or not the soil contains enough calcium, because adequate calcium actually increases soil flocculation thus helping to increase soil porosity and allowing sodium to be leached more readily from the soil.
Sulfur or sulfates, including gypsum, should not be used to rid a soil of sodium until the soil's calcium saturation is at least 60% or higher. If below 60%, this would require limestone, finely ground oyster shell, laying-hen manure or some other source of material that principally builds calcium levels. Do not consider gypsum in such cases due to the high sulfur content, until sufficient calcium to reach 60% saturation of the soil has been added. (An exception would be the lighter soils such as sands where adding a ton or less of gypsum by itself would increase the calcium level in that soil to 64% or higher.)
Then Consider Gypsum Once 60% calcium has been achieved, gypsum, at one ton or less per acre per year, would be the material of choice to use on soils with too much sodium until the calcium reaches the maximum saturation for that particluar soil. Again, this should be part of a determination made by the soil test used. Once that point is reached, sulfur and sulfate fertilizers without calcium can still be used in moderate amounts to decrease any remaining excess of sodium. Specific amounts would depend on the actual soil analysis from the land in question.
The above % figures relate to soil tests that we process, the soil analysis from other labs will be different, and the guidelines given above will not be specifically valid if such is the case.
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