Qualified Consultants who have studied and utilized the Kinsey-Albrecht method of soil testing and recommendations, and who can advise on its application for soil fertility needs.

Filter by Country/State

Considering the Effects of Potassium on Manganese and Soil Fertility

Effects of Potassium

Potassium is considered as a primary nutrient needed in all types of agricultural production. It helps provide cold tolerance to plants. It also aids in water utilization, or as an old saying goes, “Potassium is the poor man’s irrigation” and all crops benefit in that way when it is properly supplied. Also, when sufficiently available, potassium is a major key for strengthening and encouraging strong cell wall development and thus enables stronger wood or stronger stalks depending on the crop being grown.

But when overused, potassium has some serious drawbacks. A severe excess of potassium in the soil will cause the clay particles to disperse and clog needed pore space so that water will tend to stand on top instead of infiltrating the soil as it would under normal circumstances. Excessive potassium can also adversely affect nutrient availability, including the tie-up of boron and blocking of adequate manganese uptake from the soil. This holds true for all types of crops, but due to generally common practices, an example from potato production should serve as a prime example to show how excessive potassium can cause problems regardless of the crop to be grown.

Most potato growers feel that to produce good yields the practice of applying large amounts of fertilizer, and especially plenty of potassium right under the seed row is an absolute must. The perception is that potato roots do not spread outward very well, and that they tend to grow straight down below where the seed is placed. Such downward root growth does show to be the case in many fields where potatoes are grown. However, based on growth exhibited in fields that have been supplied with the correct amount of each needed nutrients, such limited root growth is actually abnormal as compared to what should and does happen on potato fields with sufficiently adequate levels of fertility.

In fact, when soil fertility reaches the desired level for growing potatoes, the plants will send out roots that will spread across the middles, growing right on past roots coming from the next adjacent row of potatoes on each side. When possible, roots grow to where the needed nutrients can best be obtained. Because of the false perception that potato roots do not or will not spread out, large amounts of fertilizer ordinarily tends to be placed directly under each row and the roots grow straight down to pick it up.

This common practice can contribute to certain problems for reaching optimum levels of potato production. One such negative set of consequences has to do with soil nutrient supplementation and plant nutrient uptake. The soil is the plant’s stomach. Feed the soil and the soil will then properly supply nutrients to the crop. Therefore, when misconceptions begin to influence growers to forego the needs of the soil and instead apply only what is perceived as needed to grow the crop, soil health and plant health can be adversely affected.

Furthermore, depending on various nutrient levels unique to each individual soil, a number of possible problems can develop or become even more seriously aggravated by applying excessive amounts of potassium fertilizer right under the row.

One such example involved a large potato grower/processor in Africa that hired us for a farm visit to consider a problem they were concerned about in the potato crop. The potatoes would begin to grow off well, but then suddenly the plants would develop weak stalks and the vines would fall over, resulting in scorching or sun scald permanently left on the stalks. Then after a time, the potatoes would stand back up and begin to grow as they should have all along. But consequently they had been injured by the sun and the concern was how much this damage was affecting potato yields and how to prevent it from happening time after time.

The first rule to consider in such cases is what Dr. Andre Voisin called, “The Law of the Maximum.” Too many, if not most farmers and growers, fail to consider or seriously place sufficient emphasis on understanding and utilizing this concept. Consequently it has cost far too many farmers, and especially potato growers in this particular type of case, large sums of money due to reduced growth and yields.

Soil samples were already in hand for these soils that had been taken and sent for a detailed analysis and recommendations. With a copy of the tests for the fields in hand it was possible to evaluate the current conditions standing right there in the field looking at the growing plants. Potassium levels were quite good in the fields, but still some additional potassium was needed to achieve the potato yields these fields had the ability to produce. And even though the recommendations plainly stated all fertilizers were to be broadcast, the grower still had applied potassium under the row just as most potato growers always do.

When everybody does it, it must be the correct thing to do – right? Well, not in this case! Placing the needed potassium directly under the row caused the available potassium level in the soil to increase by too much. In such cases, the first effect is to tie up boron in the soil. Because once potassium exceeds 7.5% of the soil nutrient holding capacity or Total Exchange Capacity (commonly confused with the “CEC” measurement which often causes this number to be overstated), it will begin to tie up the boron. Then if enough boron is not replaced via foliar applications it can result in smaller potatoes, because boron is needed to transport the starch out of the leaf and move it into the tubers. But even though the lack of boron was affecting the size and weight of the crop, it was not what was causing the temporarily weakened stalk problem and reduced stalk growth for this African grower.

Where too much potassium is applied right under the row, if either by itself, or in combination with sodium, the total saturation exceeds 10% of the soils nutrient holding capacity (TEC), it will begin to cause plant uptake of manganese to be blocked. In such cases, soil tests show the soil has plenty of manganese, but there is so much potassium and/or sodium there that the manganese has trouble competing in terms of availability and uptake by the potato. This was the problem the potatoes were having in this grower’s fields. The higher the percentage goes above 10% K, the harder it will be to get manganese taken up by the plants even though the soil test may show excellent manganese levels. Even though the excessive level of potassium does not tie up the availability of manganese in the soil, it does, along with sodium, block adequate manganese uptake via the soil into the plant.

When the potassium and other nutrients were placed below the seed, the potatoes sent their roots right on down to take up needed nutrients. But the extra potassium applied in that confined area was too much for that soil and once the potato roots entered that area, the blocked uptake of manganese caused weakened stalks and the problem that resulted in sun scald on those stalks.

Potassium is the first key to stalk strength, but manganese is also needed for strong stalks. When the potatoes could not take up enough manganese, all that potassium was no substitute for the needed manganese. The potato stalks became weak and fell over. Once the roots were sufficiently able to grow out of that excess potassium zone, the plants could again take up enough manganese and the vines straightened up and began to grow as they should.

That was several years ago and since that time, no potassium is recommended under the row on potato land for that company except in the case of new land with extreme K deficiency. In potassium deficient soils, there will be no problem with weak stalks in potatoes grown there as long as the fertilizer is added in the proper way.

Effects of Manganese

Even though very important to stalk strength in all crops, manganese provides several other benefits for land being used for crop production and when too much potassium is applied, it will contribute to these problems as well. Without manganese plants grow off more slowly. A lack of it also affects seed set. And for potatoes, in terms of common scab, the worse the manganese deficiency in the soil, the more problem there will be with this disease.

One big problem for growers is knowing what really is enough manganese in the soil for each crop? The answer tends to be confusing because of the various ways to measure and report manganese on soil tests. In fact, the numbers we recommend just to be at adequate levels in the soil will be reported as high to excessive levels on some other soil test reports.

There is yet another problem that growers may have in trying to determine when there is sufficient manganese for the crop. This has to do with using a leaf analysis to determine if plants have sufficient or insufficient manganese. When the specific soil test we utilize shows manganese as even slightly deficient, common scab can be a problem for potatoes. Yet in too many cases, the leaf analysis shows the level of manganese to be adequate, even when our testing still shows manganese as deficient in the soil. Which should be believed? The one that solves the problem!

Keep in mind that many potato growers use a metallic manganese based foliar to treat for disease. This can greatly skew the levels shown from the leaf test. But this is not the entire story. Potatoes have been used as an example here due to their extreme sensitivity to manganese deficiency. And at times, even those who have not used a foliar manganese can have leaf tests that show manganese as too high when in actuality the soils are still too deficient to correctly supply plant needs. We find this consistently tends to be the case with leaf testing for most micronutrients, not just manganese, as compared to the levels shown to be required on the soil test to properly solve each deficiency. Such deviations can also be a serious problem when considering needs for other manganese sensitive crops such as wheat, grapes and all types of trees, but especially English walnuts and black walnuts.

There is still another precaution that should be considered when evaluating available levels of manganese for crop production. Even leaving dust on the leaves can cause manganese levels to appear to be too high in the plant. A good way to detect this is when iron and aluminum are also shown to be extremely high on the same analysis. When that happens, test again with clean plant tissue to be sure.

Perhaps an additional word of caution should be given here, for even soils that may initially have an adequate amount of manganese can develop a deficiency problem if enough lime is applied to cause manganese to go from sufficient to deficient. This can happen when any material containing a sufficient amount of calcium is applied on soils that barely have enough manganese (with even worse results when the soil is already deficient in manganese), because when calcium is applied, as it becomes available over the next one to three years, it will tie up a certain amount of soil-available manganese.

If the soil has enough to stand the amount of calcium applied, manganese will not become the problem there as a result of applying needed lime. That is one reason why in some areas potato growers can apply calcium limestone and have no problem with common scab, but in other areas no one will dare apply it. And due to soils needing calcium for adequate uptake of all the other nutrients (including N-P-K) if the problem is not solved, crop production will not only suffer but may even decline in terms of yield.

Yet the issue of adequate manganese in the soil can be overcome by applying a sufficient amount of the correct type manganese sulfate. The needed amount should be based on a detailed soil analysis which can accurately determine the desired level in the soil. The test should be such that it can accurately determine how much manganese is required to overcome any tie-up from added calcium as well. Whether already deficient, or for a potential decrease in manganese due to liming or other sources of calcium (such as poultry manure), only the use of true manganese sulfate should be considered for adding to the soil to sufficiently build up the manganese level to solve that need. From the testing we use, that need will be reflected and solved based on the use of one pound of actual manganese for every pound shown to be lacking. If that does not happen in the next twelve months after an initial application, someone is likely providing the wrong advice.

Though comparatively few in number, there are some soils where manganese does not build well. Waterlogged soils are generally the best examples. Heavy coarse yellow clays can also be quite deficient and hard to build up and maintain. When using manganese oxide or manganese oxy-sulfate the soil analysis has never shown to increase soil manganese levels, let alone help build up to adequate levels. Although oxy-sulfate may help feed the plant if enough is applied for each given set of needs, it will only help for the current crop year at best.

Some soils do not even build well using manganese sulfate. In a very few cases it has been necessary to apply the needed amount for two or three years in a row to reach the desired minimum level. In such cases, the use of ammonium sulfate as a nitrogen source may help, but generally the amounts used do not show much progress in building up soils deficient in manganese. A crop which can also help to increase manganese availability in the soil is rice.

Just keep in mind that the primary elements, N-P-K, truly are primary in terms of getting enough nutrients there to grow the crop. But when any one of these three are over-applied, providing more than the soil can tolerate, those same elements can cause a whole new set of problems, not just for potatoes, but for all types of crops and growing plants.

– Neal Kinsey

Deep Nutrient Sampling/Necessary Fertilizer Application

The Aerobic Zone

When considering how to build up soil fertility, the most important zone to consider is the aerobic zone – the top 6 to 7 inches (as deep as a fence post rots). This is the part of the soil that contains the micro-organisms that can only operate properly when adequate oxygen is present.

There are some exceptions to sampling the aerobic zone [roughly considered 6.75 inches because an acre of soil down to this depth will generally weigh about 2 million pounds]. One is when all materials must be placed on top of the soil and will not be worked into the top 2 inches (5 centimeters) or more. Tree crops such as citrus, almonds, apples, pecans, and even timber or trees and landscape plantings are a part of this category. No-till crops, pastures, hay meadows, lawns and turf grass are other important examples.

Take the topsoil sample from only the top 4 inches (10 centimeters) for such cases in order to avoid over-saturation by adding too much of any nutrient to those top few inches. This is necessary and extremely important to consider because too much of one nutrient added to the soil can cause a deficiency of one or more of the other nutrients needed there. For example, too much phosphate will tie up zinc, too much potassium ties up copper, and too much of any one of the various liming materials will tie up at least a portion of just about all the elements we can measure with a soil test, with phosphate usually being the exception. Thus, borderline levels would now become deficiencies for the plants intended to be grown there.

Another exception to the rule of sampling the aerobic zone is when the fertility of the land for establishing new trees or vine crops is being considered. We have some clients who test for certain nutrients to a depth of 48 inches (125 centimeters) to consider what can possibly be done to positively influence fertility levels. In such cases deeper sampling and analysis may be utilized by taking samples in 6 inch (15 centimeter) increments to the depth soil nutrients can be safely applied and mixed.

Think of the aerobic zone as the most important consideration for soil testing. Even more, track this area separately because, given the choice, every plant will feed in the aerobic zone. The soil is the plant’s stomach! The aerobic zone is the area where nutrients are most available because the microbial activity is greatest there. Plants when allowed to grow normally will send the major feeding roots into that zone because it is the area that will provide optimum nutrient uptake.

Fertilizer Application

Depth of Fertilizer Application The depth to which soil sampling should be done after considering the aerobic zone depends on the circumstances and the way you intend to use the information gained. If a ripper or subsoiler will be pulled through at 5 feet deep or more, it may be of interest to see what is down there. But once you know what is lacking, how can you affect fertility levels at that depth?

Essentially at that depth, you have what you have to work with and not much chance of affecting it except to break up any hardpan and allow roots and moisture to penetrate more easily so as to better utilize what is already there. As this happens over the years the levels in the lower depths of the soil will begin to show a change, and the more roots the more the changes become evident.

A major key to effective soil fertilization is the use of sampling to measure what you have, as deeply as the roots may penetrate. But then, continue to utilize testing at the deeper levels to prove or disprove what changes are thought to be possible there.

Fertilizer Mixing, Nutrient Concentration Next, determine how deep you have the ability to work the soil and the efficiency of the equipment used to mix the applied materials with the soil. The key is to achieve a homogeneous mix. The rule of thumb is “adequate mixing of the nutrients applied is only satisfactory to half the depth the equipment is able to break up and work the soil”.

Keep in mind that thorough mixing is of utmost importance. Where the material is applied in clumps, if it is something the plant requires, roots will concentrate there and we again have to consider the “law of the maximum”, P ties up zinc, etc. But also, would the contents of the clump cause toxicity problems for roots that would normally penetrate that area? Better to be safe than sorry!

When the depth to which fertilizer can be thoroughly mixed is determined, figure the needs in 6 – 7 inch increments once you drop below the aerobic zone. For example, if it is determined that implements that can work the soil to a depth of 30 inches will assure adequate mixing to 15 inches, back off to 12 inches and apply the materials calculated for that depth. If 18 – 20 inches, figure to the 18-inch depth, etc.

The question that matters most to this point is how well will the fertilizer, lime, compost, etc. be mixed with the soil. When it comes to soil fertilization, it is a good rule to follow that in the long run too little is always better than too much.

Considerations for Specific Nutrients

For soils needing an increase in fertility, the following comments are of particular importance, keeping in mind the points made above:

Phosphate If a soil can be thoroughly mixed and it would not provide an excess of nitrogen, applying 250 lbs./acre of 11-52-0 for each six inches of depth would not be too much phosphate. Furthermore, the nitrogen will be gone in no more than 8 months, likely far sooner. However, better to thoroughly mix 250 lbs./acre in the top 6 – 7 inches just before planting than do a poor job to a greater depth. For organic growers using 500 lbs./acre of soft rock phosphate, the concept would be the same, just so long as nutrient availability would also not be harmed from the extra calcium that will be added there.

In addition, the deeper you place the phosphate, the less efficient it will tend to be at remaining in an available form over time. But from what we have seen, if it is correctly applied and mixed, it will increase P levels in the form the plant needs, to the depth it is applied, even though availability is not as great the deeper it is placed.

Sulfur will tend to move downward through the soil. Placing it extremely deep is not an efficient use of sulfur unless there is some other nutrient excess that could be affected properly by its use. Many sampled areas would not benefit from sulfur placed in the 12 – 24 inch levels, but others could benefit, due to very high or excessive sodium levels.

Concerning the application of lime and/or gypsum to the soil, if the topsoil and subsoil need the same amounts, consider the complete depth for receiving all that is required. But if the subsoil needs more than the topsoil, the question is, how well would the amount needed deeper down ever be kept from the top portion? For this reason, only apply to that soil what the subsoil can stand when it is equivalent to or less than the topsoil and when it can be completely mixed as required. So long as it can be mixed correctly, needed potassium from 0-0-50 would benefit when recommended and applied to the complete depth required.

Boron should only be applied to the aerobic zone. If there is ever a hardpan, the boron moving from the top could accumulate to toxic levels somewhere in the root zone. The more that is applied at once, the greater the chance that damage can happen. Since boron will leach out anyway, or move downward from the top, it is best to apply it on top and only where shown to be required.

Iron sulfate (in the proper form – white or blue green in color) can benefit the crop if truly needed. However if the aerobic zone is deficient and the immediate subsoil exceeds 40 ppm and the ppm of manganese is adequate, but below iron, deep rooting crops can compensate and will likely receive an adequate amount to supply the need. However, if liming materials are placed in the subsoil and iron is barely adequate or deficient, this will only make the problem worse for future root and top growth. Even more, the extent of the problem will not be determined until the end of the third year after the lime has been mixed in. On specific samples that have the need, applying the recommended lime should not be a problem.

However where calcium is too high, iron availability may be just as much a problem at greater depths. Iron applied here will only benefit to the extent it can be worked in at all depths. Even if the iron were thoroughly mixed and it was twice the amount needed in the top 12 inches it would only serve to benefit in the long run, so long as it can be kept in an available form, or converted to an available form by sulfur acidulation.

Manganese tends to tie up in the soil the deeper it is placed or even naturally as you continue to check it at lower depths in the soil. An application to the aerobic zone is likely the only time manganese will have a lasting benefit for the amount of material required and the subsequent cost.

Copper tends to release slowly and remain available, but good microbial activity in the aerobic zone seems to help provide a more even distribution. Without further information, the expense of building copper in the subsoil may not be cost-effective because of the lack of microorganisms to help. Another consideration is whether it can be thoroughly mixed so as not to cause a problem. In general, no problems have been experienced with topsoil applications of copper sulfate up to 35 lbs./acre when broadcast and well mixed.

Although zinc tends to decrease in availability with depth, the greatest problem would be if clumps or high concentrations would accumulate in specific areas and cause phosphate tie up. It is likely that an even distribution, even at deeper levels, would pay dividends in years to come.

Compost can only be properly evaluated with a representative analysis in order to determine what it can do for individual soils. Depending on the nutrient levels present, and the amounts available for application per acre, some or all of the phosphate and potassium may be supplied. The big question is, can it be mixed, and will sufficient amounts be available, for the lower soil depths.


If there is any doubt, it is recommended that fertilizer materials be applied and worked in to the minimum depth of homogenous mixing as a certainty. We can always continue to treat from the top and make better progress than where excesses occur that we cannot then easily and economically correct.

– Neal Kinsey

The Dangers of Using Too Much Lime

Can you use too much lime?

Perhaps the most frequently asked question by those using our soil fertility program is, “Can I put on a higher rate of lime than you are recommending for this sample?” Generally, this has to do with getting the limestone spread, because the owner of the lime-spreading equipment says he either cannot or will not apply such a small amount.

Many times a farmer has been told, “You can’t use too much lime.” That is not true. From our experience in working with thousands of acres that have previously been over-limed, we know you can easily apply too much lime, not only for crops such as berries and potatoes, but for whatever crop you are intending to grow. And if this happens, it can be far more expensive to correct than the cost of the extra limestone that was not needed, and getting it spread.

It takes 3 years to show

What makes identifying the problem somewhat complex is the fact that it may take three full years to see the whole picture of total effects from any lime applied on a field. If too much is used, it is not normally noticeable in the first year. In fact, if some lime was really needed, but substantially less than was spread, improvements will be most evident in the first year. But by the third year, when problems from any excess will then be most evident, many growers have already forgotten the possible long-term effects of the limestone application, and tend to place the blame elsewhere (on weather, fertilizer, seed, and so on).

The adverse effects from over-liming can show up in a number of ways. Principally we must deal with the damage caused from too much calcium and / or magnesium as well as the effects of increasing the soil pH.

Effect on pH

For example, adequate phosphate is a big concern for most farmers in terms of fertilizer. Just by increasing soil pH, phosphate may be released and increased in the soil. But if the pH goes unduly high, phosphates can also be tied up. Using more than enough lime can cause the pH to increase by so much that this happens. In addition, pH can tie up other elements as it increases, such as boron, iron, manganese, copper and zinc.

Effect on Trace Elements

The higher the calcium level climbs from the use of calcium carbonate limestone, or gypsum, or from the calcium make-up of dolomite lime, or any other significant calcium source, the more chance the trace elements, plus potassium and magnesium, have of being tied up in the soil – to the point that the crops can no longer take them up. Then plants suffer in terms of quality and yield. This is also a critical point to understand, if the levels of any of these elements, which can be tied up by too much calcium or too high a pH, are already borderline in the soil (in terms of availability for plant use), deficiencies can occur unless they are able to be determined beforehand by testing, and treated accordingly.

Effect on water use

Use of calcium also increases the pore space in the soil. This is a desirable result until pore space reaches 50% of the total soil volume. But when too much calcium is applied by over-liming, so much pore space can result that the soil dries out much easier than before. So you can lose efficiency of water use, whether it’s from rainfall or irrigation, if you over-lime your soils.

Consider all sources

Some growers might think that just as long as there is not too much limestone applied, there is no problem. High calcium limestone (calcium carbonate) and gypsum ( calcium sulfate) are generally considered the most common sources of calcium. But the problem can be caused by other materials too. The list includes oyster shell, rock phosphate, kiln dust, marl rock (ground sea shells), sugar beet processing lime, and stack dust from the scrubbers of utilities or industrial facilities burning high sulfur coal. All of these, as well as poultry manure, especially from laying hen operations (where calcium is supplemented to strengthen the egg shells) can be a significant source of additional calcium. Compost should also be suspect until the actual calcium content is accurately determined. Also certain types of wood ashes that are applied at high tonnage rates, and some sources of irrigation water, can contribute substantially to the levels of calcium in the soil.

Don’t be fooled, too much calcium can cost you money in terms of lower crop yields. On the other hand, even in crops such as berry or potato, so called “low pH crops”, too little calcium, or too low of a pH, can cost you just as much or more, if not corrected.

Use a soil test.

The best way to determine what is actually needed or not needed in terms of liming is to use a detailed soil analysis. The soil analysis should include measurement of calcium and magnesium and the percentage saturation of each in the soil. (As we explain in Hands On Agromony, growers cannot determine whether lime is required simply by measuring the pH of the soil.) The soil testing methods used by Kinsey Agricultural Services always include checking for both calcium and magnesium levels to determine if there is too little, too much or if the proper amount is already there. Chapters 2 through 4 of Hands On Agronomy help explain this in greater detail. An overall picture of what over-liming actually does to a soil can be seen by taking a soil sample prior to the use of the lime and following up each year for the next three years.

So when someone asks, “Why can’t we just go ahead and apply 2000 lbs anywhere that you call for less than that?” the answer is: if you can never apply too much limestone, that would be fine. But too much limestone can be a potential problem for the soil and for the crops to be grown there, because it can tie up other nutrients also needed for the growing crop. So it is far better not to use too much lime.

Yet when needed, applying the correct amount of lime makes a real difference to how your crops are going to respond, whatever crop you may choose to grow there.

– Neal Kinsey

Improving Yields Reduced by Excess Water

Loss of nutrients to water

During each growing season, in certain agricultural cropping areas, rainfall can be heavy to excessive at times. For many areas this can be especially true in the winter and spring months. Combined with high yields, extra water can have a very detrimental effect on soil fertility. Growers with fields that have been heavily irrigated can experience the same type of problems.

In many fields too much water has caused some fertilizer nutrients needed for good crop production to be leached, or washed downward out of the topsoil. This is especially true for nitrogen, sulfur and boron, as is generally expected to be the case. But under the right conditions, calcium is another element that can be lost due to high amounts of water. As shown by soil tests, in order to avoid the loss of crop yields, more liming needs to be done in many areas. Yet in recent years less emphasis seems to have been given to the importance of liming than has been the case in the past.

The need for limestone

Using limestone to increase crop yields has become a significant factor in more and more fields. Some fields being checked for calcium losses on a continual basis have changed drastically within three or four years. Such changes are particularly expected on fields that do not have a history of good liming practices, and on fields that receive inordinate amounts of nitrogen or sulfur from whatever source.

Watch that limestone!

But just applying some type of lime to correct the pH is not generally the best answer. In fact, some of the fields that have received high magnesium (dolomite) lime can still have an adequate pH, and yet be limiting your crop yields. This is because the levels of three other crop nutrients, in addition to magnesium, can greatly influence crop yield, and a need for them may not be properly reflected by the pH. Calcium, potassium and sodium are the other elements in question. If soils have too much magnesium (or too much of any one of the other three), the pH can appear to be okay or even too high, when in fact the soil does not have enough of one or more of the other three nutrients needed to produce at its best.

You have to balance the nutrients

The only way to know what is actually the case is to have a detailed soil analysis run on the soils. Such testing must measure the levels of each nutrient properly. For those who are new to our soil fertility program the test procedure which we use provides these answers. And from this analysis it can be determined what lime, and how much, is needed from the various available sources. Just putting on lime is definitely not the best route to take! Too much high calcium lime (or calcium from other sources such as manure from laying hens, finely ground oyster shell, ground marl rock, and in some cases gypsum, soft rock phosphate, or even compost) can tie up nutrients. This includes potassium, phosphate, boron, iron, zinc, copper, magnesium and/or manganese.

High-magnesium lime

Dolomite, or high-magnesium lime, can cause problems too. When dolomite is applied in too large of a quantity it can cause an excess in magnesium and have a negative effect on yields. The problem is it can be as long as three years after the excess lime has been applied before seeing the greatest amount of potential damage to the crop yields. By this time, unless the grower has kept good records, a connection between the liming and declining yields may be overlooked. (A moral here is to keep good records of when, where, how much and what type of lime each field receives.) Have you applied dolomite lime on any of your fields in the last few years? If so, count three crop years from the time of application and check the yields that year and thereafter as compared to yields prior to liming. Even if the applied magnesium from dolomite lime will have a detrimental effect, do not expect to see that yields have dropped the first year.

For example, when too much dolomite is applied to land for cotton, it can eventually cause the plant to send out two lesser roots instead of one longer taproot. These roots do not go straight down, but curve to one side instead, and have less depth than the one taproot would normally have. (If you rip and hip, this effect will not always be as evident.) It will take three years to see the full negative effects of overusing dolomitic limestone. But when overused, once those effects have come into full effect it can cost a cotton farmer about ¾ of a bale cotton per acre, every year, until the problem is corrected!

Excess magnesium costs money

In corn, on medium to heavy soils, a high level of magnesium (15%+) costs the farmer 10 bushels of corn per acre. Above 20% magnesium on the soil test reduces the yield by another 5+ bushels per acre. In addition, it will require more nitrogen to produce each bushel of corn every year until the problem is corrected. In legumes, taking soybeans as an example, 13-14% magnesium levels can cause 10 bushels per acre loss per year, even when all other nutrients are present in the proper amounts

Be sure what your soil really needs

Even though too much, or the wrong type of lime can cut yields, limestone should always be applied where shown to be needed. Applying the proper amount of lime in the right form can provide far greater increases in yield than the losses that occur from misuse. Have your yields suffered in certain fields in the past few years? If so, avoid the mistake of failing to correctly check for and properly apply any lime that is needed. Just be sure that you use enough to correct the problem, but not so much that it causes problems three years from now and several years thereafter. If there is a need for lime, autumn is the best time to spread it for next Spring’s crops. Do it correctly as needed and see the difference liming can make for crops over the next several years.

– Neal Kinsey

For Those Who Utilize Soil Tests

In a survey conducted some years ago, farmers were asked whether they believed that soil testing was something that should be used for raising better crops and improving soil fertility levels. 82% answered “yes”. When these same farmers were asked if they used soil tests, only 28% said” yes”!

In agriculture today, anecdotal evidence suggests the percentage has improved. To remain profitable in agriculture under present conditions, every farmer and grower should consider that fertility levels must be measured. These measurements can then be used to manage soil fertility to more precisely achieve top production and quality, while still keeping costs at the minimum necessary to meet the goal.

The following information is especially meant for those who already believe that using soil tests is important. It is particularly intended for those who count on such tests to guide them in terms of providing better soil and plant nutrition, and is an attempt to provide additional “food for thought” to those who really work at managing fertility, using soil testing to measure what they have, from farm to farm, field to field, and perhaps even from area to area within a field.

Test your soil tester!

There are hundreds of soil testing laboratories, and many different methods used for determining the levels of nutrients in the soil. Which laboratory or which methods are best to use is not debated here. If you have tests that work well for you, use those tests. If you are not sure then test your soil tester! – as we encourage everyone to do, in Hands On Agronomy and in our material Taking A Good Soil Sample.

For those who use soil analysis to manage soil fertility, there are several questions that ought to be addressed:

  • How often should you test to maximize benefits?
  • How many samples are needed to properly represent a field or farm?
  • How deep should a soil sample be taken?

It is surprising to see how many different answers are given to each of these questions. And not all of those answers are correct! Each question will be expanded and discussed below.

How Often Should You Soil Test?

Rather than one general answer to this question, the focus should be on other factors that have to do with the land use, the crops to be grown, and the needs of the operation.

A soil sample every 3 or 4 years will only make possible a somewhat general indication of fertility (the stated purpose for most soil tests that only check for pH, phosphate and potassium) without providing the very detailed analysis required for specific management decisions. This is not an approach we would recommend.

We recommend sampling every year. On the other hand, at times when initial soil test recommendations have not been accomplished sufficiently and further basic work needs to be done as indicated by previous samples, taking another set of tests would not generally be advised. For example, if a test accurately shows a need for lime and it has not yet been applied, spend the time and money on liming, not taking more soil samples. Or, possibly the amount of principal materials required would be more than has been budgeted for fertilizer and it would take 3 or 4 years to accomplish the most needed applications before being feasible to proceed.

Then, too, some people may not believe it is possible to determine the full effects of lime or other materials being applied without waiting several years to be sure it will show up. It does require up to 3 years to measure the full effects from an agricultural limestone application, but if the calcium and magnesium content and the fineness of grind are both correctly determined, it can be pro-rated beneficially over all 3 years, so long as accurate spreading records are kept. (Especially keep records of the source of the lime, the year, the month or season, and the tonnage applied.)

What are the economic benefits? If you are taking soil samples, and have the capabilities to follow through on what is shown to be needed, don’t just take soil samples every 3 or 4 years. Instead, stop and analyze the situation. How valuable is the crop? Those who are growing seed crops, or crops of higher value, should test before every crop. One client who owned a seed farm, for example, from the time sampling first began, would sample twice within a 12 month period, when raising a seed corn and a seed wheat crop. We also have commercial vegetable and berry growers who sample to fertilize for their principal crop, and again prior to whatever will be used in the rotation, even if it will be cover crops. Some of our largest clients grow tree fruits and nuts, and they correctly take soil sample every year. Even cotton, corn, soybeans, and wheat producers who are achieving high yields should do the same thing, and many who are clients of ours do just that. One alfalfa grower put it this way, “If I soil test properly, it costs me less than 1 or 2 small square bales of hay per acre. But if I don’t test, it can cost far more than that buying fertilizer I really don’t need, or through loss of yield for failing to apply something the soil did need”

As long as it is possible to purchase and apply what is required for the crops to be grown, soils should be tested before every major crop. And for plants and crops that are grown over a period of years, soil tests should be taken prior to any major fertilization program that involves materials that are used to build up the soil fertility levels.

Know the soil fertility of your land. Always manage your soil testing work to correctly measure what you are doing, including progress or regression in terms of soil fertility. One of the greatest mistakes in agriculture today is failure to sufficiently use soil tests to properly measure, and correctly mete out, the fertilizers and soil amendments needed for the land.

How Many Samples Are Needed To Properly Represent A Field or Farm?

The next point to consider is the question of just how many soil samples should be taken from an area, field, or farm. Above all, do not let the number of different fields you have determine the number of samples you will take. That is, do not assume you are doing the job correctly if you take one composite sample per field. Sometimes that may be the case, but too often, it is not.

Where to pull the soil samples. To begin, consider pulling a few samples from good, productive land, some from average land, and some from poor production areas. Then after you see what is involved, depending on the fertilizer budget and timing, additional samples could be taken where the need is evident.

At the beginning decide what should be the smallest area worth taking the time to fertilize separately. Then pull samples on those fields selected for testing, taking samples from any areas which are that large or larger, where visible differences are detectable.

When farmers or growers are only willing to treat whole fields, yet there are observable differences in that field, (in soil types, yield differences, weed populations, large problem areas, etc.), that operation is losing top potential for the field in question. This is another big mistake that is continuously made by farmers, growers, and fertilizer dealer field men. Be sure to pull sufficient soil samples for optimizing soil improvement and yield.

Yield monitoring One of the most revealing new developments in high-tech agriculture for some growers has been computerized yield monitoring on harvesting equipment. Suddenly, producers can see the vast differences from the best to the worst in the same field. Using a detailed soil analysis, this method can then show why these differences are so great – with fertility as the key. Whether in good or poor yielding areas, fertility is generally always a major key, even when other factors are also involved.

Use of the information provided by yield monitors has helped farmers and growers see the importance of doing a more complete job when it comes to taking soil tests and supplying the fertilizer needed for each area.

The longer each person works with the Albrecht Model of soil testing, the more they will realize the costs in yields as well as those due to using too little or too much fertilizer will usually be far greater than those for testing each soil properly. Again – proper measurement is a necessity to adequately manage fertilizer needs and expense and for top yields and top quality.

How Deep To Sample?

The proper depth needed for an accurate soil sample will depend on several factors. If the soil will not be worked at least 2 inches deep, sample only the top 4 inches. This would be true for pastures, hay meadows, no-till crops, orchards, vineyards, lawns, golf courses, etc. Of course, many will disagree when it comes to hay meadows, and even more so for orchards or vineyards! But the determining factor here should be the depth that materials can be expected to saturate between soil samplings. This is one big reason why we advocate sampling every year. Four inches is best in all these cases, even if sampling is not done every year.

This depth avoids the chance of applying excessive amounts of materials in any given area where the plant will be taking up nutrients, thus ensuring that exceeding the “law of the maximum” (which means robbing plants of certain nutrients due to the inhibiting effect of excessive levels of others) will not happen.

For soils that will be worked or tilled, the proper sampling depth is as deep as a fence post rots. Generally this is around 6 1/2 – 7 inches deep. We use 6 3/4 inches as an average, since an acre of soil to that depth weighs approximately 2 million pounds.

Soil will usually tend to drop in terms of fertility the deeper you go. So samples taken too deep make it appear you need more fertilization than is truly the case. But in cases that matter, consider taking subsoil samples in at least some of the most important areas, to accurately measure the general levels of nutrients deeper down in the soil

When to sample deeper There are times when samples need to reflect what is below a 4 inch or 6 1/2 inch depth. For example, iron may be deficient in the top few inches, but present in sufficient amounts below that level. In such cases, take the top 4 inches as one sample and then a subsoil sample to the depth desired below that level. For example, some areas that will be planted to trees or wine grapes will be sampled as the top 6 3/4 inches, then 6 3/4 – 12 inches, 12 – 18 inches, 18 – 24 inches, 24 – 30 inches, and 30 – 36 inches.

This is especially important when soils will be worked unusually deep, or roots are expected to draw nutrients from depths below the topsoil layer. In addition, be sure to sample down to the depth of complete nutrient incorporation capabilities. This should be figured at half the depth to which the soil will be worked. For example, if an offset disk will be going 36 inches deep, figure the top 18 inches will need to be sampled and properly corrected for an adequate “balance” to that depth to be maintained, and for maximization of biological activity.

Again, keep in mind that based on extensive work over the years, it is true that soils tend to be lower in overall fertility the deeper you go. But there are also soils that have higher nutrient levels below the portion normally tested. The only way to be certain is to take subsoil samples, at least in key areas, to determine the actual levels.

In Conclusion

We recommend that under normal circumstances farmers and growers should sample every year. Pull a separate sample from each area of a farm or field which shows differences of any type, so long as the area is large enough to fertilize separately. And sample to a proper depth, depending on whether the soil will be worked, and to what depth.

For additional information on taking soil samples see Taking Soil Samples also our book Hands On Agronomy.

– Neal Kinsey

Rebuilding Soil Fertility

What kind of soil fertility should the average farmer or grower expect to have?

Most farmers have land that has been in production for many years. A sizeable portion of that land will have received at best N-P-K and lime over those years. But many who make their living in agriculture tell us that in spite of new seed varieties and good management practices, their yields have either stagnated, or begun to drop. When it comes to production and / or quality, this is the case in spite of using as much or even more fertilizer than before. A large number of clients tell us at the start of using our program that they just want to achieve what they used to achieve in terms of the crops they are growing.

Follow the program to get results.

We have clients who sample every different type of soil in every field every year and strive to do all that the soil test indicates needs to be done. And for “high dollar” crops this may be followed by several leaf tests per year. Clients have been amazed at the increased productivity of their “good soils” after 3 years of following the recommendations for improving those soils. For yields to reach this point we find there is more to bringing them up in fertility than just adding nitrogen, phosphate and potassium. The higher the yields have been, the more this proves to be the case; soils do not have an endless supply of the required range of nutrients in a form that is available for plant use, other than what is supplied with typical N-P-K fertilization.

Assessing the cost.

Most growers will not be so blessed as to have soils that can be built up or restored to excellent fertility levels on the same fertilizer budget they have been using year to year. The exceptions would be those who have maintained an excellent liming program and / or have been successfully using higher amounts of phosphate and potassium. If you are working with large acreage, just expect that in the beginning it may cost you more than a “sensible” budget will allow. That is – until you verify on some of your own land that these expenditures will truly pay for themselves.

Where to start.

If a soil fertility building program appeals to you, but you wish to limit your budget, consider sampling perhaps 10% of the acreage to learn what is shown to be needed. Do not just sample the worst 10%;that will generally be the most expensive soil to correct. Send some good soils, some average areas, and some problem soils for testing. This will give an idea of what it will take in all of these various situations, and provide an opportunity to see what nutrients are there in your better soils as compared to the poor ones.

Next, determine to set aside enough of your fertilizer budget for at least a field or two, so as to follow through on the program each year for the next three years. Make the acreage large enough to buy materials in economic quantities and small enough so as not to cause economic hardship for your overall operation. It doesn’t have to be the entire acreage you tested, but it should be substantial enough to validate whether the benefits of fully implementing the program will justify the fertilizer costs.

The Soil Test.

The Albrecht Model of Soil Analysis & Recommendations is a soil management program designed for the grower. The soil analysis measures the nutrients available to the plant from the soil by performing specific nutrient tests in the same way every time. Such measurements, related back to the soil chemistry, effectively reflect the soil’s ability to provide the elements (in the form the plant requires) for both top production and top quality. The test results in most instances will show a correlation between yield and the balance between soil nutrient levels.

Yield variation will map to soil nutrient balance.

As a test, some clients have provided a map correctly drawn according to GPS zones or yield monitoring, without any hint of yields, and asked us to tell them from the soil samples where the good and bad yields will be! And it is true: the areas of “good yield” will usually be the areas shown by the soil test to be closest in terms of nutrient balance, and areas of “poor yield” are more likely to be shown as most lacking in essential nutrients which affect that crop. The Albrecht model of testing is that accurate – if the soil sampling is done as prescribed, and the correct way to interpret the levels is understood.

The accuracy of the test is further verified in the fact that for every pound of plant-available fertilizer material that has been applied, the test will correctly show this to be the case, as long as the soil pH is not excessively high. The test for micro-nutrients reflects the addition of those elements, pound for pound in the soil. This is true as long as they are properly applied and adequate time is allowed for the materials to show up as available on the soil test. Even with a very high pH, you can generally build the levels, it just requires more time and material to do so. From our experience, many growers with excellent yields are still losing out in terms of quality and even better production, because trace elements are so limiting in their soil.

Understand the Numbers!

Every soil testing company will have its own set of measurements, generally very different to those as shown when using the Albrecht Model of testing. For example, we express the levels of trace elements such as zinc, copper, and manganese differently when compared to other soil test reporting methods. As a rule, our measurements will be expressed as much higher numbers. This may cause alarm to some consultants and fertilizer dealers if they are not trained to know what these levels actually represent! And these persons may say (incorrectly) that levels are already too high, when in actual fact, the level reflected is still quite deficient.

The important thing though is how well the numbers can be used to interpret what that particular sampled area performs like at the present time, what the potential is when the proper levels are achieved, and what is required in terms of materials to achieve those levels. Is the soil test accurate enough, and the person who uses it to provide advice at least experienced enough to determine the good production areas from the bad, and explain how the levels on the soil test will be affected by the materials and the recommended amount he suggests? Test your soil tester, that includes us too if you wish!

More on Albrecht Model Concepts.

There are several concepts in reference to the Albrecht Model of soil testing which can be verified by the test itself, in addition to the observance of field conditions. Some of those concepts will be briefly mentioned here, and we hope to expand upon them in subsequent articles.

First is the concept of soil balance. Some people say there is no such thing as balancing the soil. But in terms of soil testing, measuring which nutrients are present, and what happens when others are added, will verify that increasing the availability of one element in the soil will reduce the availability of one or more of the others. In other words, when adding a nutrient to the soil to be maintained there until the plant can use it, that particular nutrient can only be held for use when some other element has been displaced to make room for it.

The Albrecht Model is based on this concept. And in fact, what happens in terms of that balance is an extremely beneficial principle to understand concerning how it relates to soil productivity. (Hands On Agronomy is a good book to begin that study.) The soil-balancing program is built upon the understanding that every time we add an element that is deficient, it will have the greatest effect upon reducing any other element that is excessive in that soil. In other words, if we have too little of one nutrient in the soil, we will have too much of something else. Supplying what is lacking is the primary approach to controlling any excess in the soil. This is the meaning of soil balance using the Albrecht Model.

Just keep in mind that it is always best to first correct deficiencies in order to help control any excesses. This may not completely solve the problem, but it is always the best and most efficient beginning. Extreme excesses may require continued use of another element at maximum amounts in order to help completely eliminate the excess and the related problems it causes. An excess is always a problem for growers, because too much of one element in the soil means there is not enough of something else. In that regard, balancing soil nutrients, one against all others measured, is extremely important to fertility, quantities produced, and the quality of what is produced.

Feed the soil to feed the plant.

This is another vital concept of the Albrecht Model of soil building. Too many fertilizer programs are built upon trying to feed the plant and would, if possible, by-pass the soil altogether. But essentially, the soil is the plants stomach. When properly nourished, the soil provides for the biological processes required to completely decompose residues and effectively convert needed nutrients from them for use by the crop to be grown there. That is why we advocate feeding the entirety of the soil by broadcasting materials that can re-build soil nutrients levels. Use a leaf analysis to feed the plant and a soil analysis to feed the soil.

Creating the proper environment.

Ultimately, having the proper environmnet is the true goal of the Albrecht Model for soil biology. This is dependent upon the correct soil chemistry (supplying each nutrient in the proper amounts), which determines the physical structure of the soil. When the chemistry is right, only then can the physics be right. And when the chemistry (the right amount of each nutrient) is correct, and the physics (25% air, 25% water, 45% minerals, 5% humus) is correct, then we have the proper environment in which the biology can thrive.

This is the program advocated and described in Hands On Agronomy and the public training programs listed on our Courses page on this website.

Visit our Contact Us page and let us know if this is the type of soil building program you feel could be helpful. And while you’re at it, we hope you will click on the “Questionnaire Section” shown on the contact page, and let us know which of the training programs that we conduct would be of interest to you.

At Kinsey Agricultural Services, Inc. we specialize in improving problem soils, as well as those generally considered to be about normal.

– Neal Kinsey