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The University of Minnesota suggests planting and Fertilizing a deer food plot.

In Minnesota, soybean is an important crop and provides a significant return for many farms.The fertilization needs of the crop are neglected while the attention is focused on other crops.The yield of the soybean crop will decrease if it lacks essential nutrients.It is important to develop a profitable program to maximize crop yields.Fertilization guidelines are a key component of profitable production.

If properly inoculated, soybean can use the nitrogen gas in the atmosphere for plant growth.The amount of fixation is related to nitrate-nitrogen in the soil.As NO3-N in the soil decreases, the amount of N fixed increases.The amount of N fixed in the nodules is small when soil NO3-N is high.N fixation increases if soil NO3-N is low.

It's an excellent source of all the vitamins and minerals.Producers are concerned about the effect of N on nodule development.

The effect of manure application on soybean production was evaluated during the 1990s.Several conclusions were produced from the research effort.The amount of N removed by the soybean crop was greater than the corn crop, leading to the conclusion that the rate of manure applied should be limited.

The study showed that the final N removal was the same for both manured and non-manured fields, and that nodulation resumed in mid-season if manure-N was applied at rates to supply less N than was removed.

There was a consistent positive effect on grain yield from the application of manure.More lodging of some varieties was led to by this management practice.The favorable environment for white mold growth and development was provided by the increased vegetative growth.Several soybean varieties had the same effect on production.When manure is used, the decisions about variety selection should not be changed.

In recent years, some scientific speculation has questioned the ability of the soybean nodule to supply adequate amounts of N late in the growing season, a situation that could limit soybean yields.There are suggestions for in-season N application for the crop.

The University of Minnesota used to conduct research at many locations throughout the state to evaluate the effect of in-season application of various N sources.The study showed that in-season application offertilizer-N had no effect on yield.

Table 1 summarizes the effect of nitrogen fertilization on yield at a single site.Nitrogen application during the growing season can affect yields.In Minnesota, in-season application offertilizer-N is not recommended.

Special consideration should be given to the use of nitrogen in the Red River Valley.The amount of NO3-N to a depth of 24 inches is less than 75 lbs./acre has been shown to increase yields where producers have experienced problems getting good nodulation.

Some N can be used in a program of 50 to 75 lbs.There are some soybean fields in the Red River Valley.In fields with iron deficiency chlorosis, growers are advised to measure carryover NO3-N before applying N.Extra N is not recommended in these cases.

If the soil test values are in the Low and Very Low ranges, the use ofphosphatefertilizer can increase the yield.The magnitude of the expected increase in grain yield is shown in Table 3.

It has been found that the probability of a response to P is less for soybean than corn.The prevalence of iron deficiency chlorosis in the sites summarized in Table 3 limited the potential for P to increase yield.

Despite the lower probability that a yield response will occur compared to corn, P application is justified because of the reduction in soybean grain yield in the very low and low soil P classes.Table 4 contains guidelines for soybean production.Table 5 contains the guidelines for potash use.

The following equations can be used to calculate the guidelines for specific yield and soil test values.

If the soil test for P is greater than 10 or 7 parts per million, there is no need forphosphate fertilization.

The following equation can be used to calculate potash fertilization guidelines for specific yield goals and soil test values.

The recommended rates are not adjusted for placement.The conclusion of a summary of research in Minnesota and neighboring states is that neither banded nor broadcast placement is superior if adequate rates of phosphate and/or potash are applied.If the recommended rates of potash and/orphosphate are broadcast before planting, the yield will usually be slightly higher.

The use of air seeders is increasing.There are many options for seeding with this method.One option is to mix the two in the same band.The seed is sensitive to salt.Placingfertilizer in contact with soybean seed is a risky practice.

Stand establishment is reduced when both the seed and thefertilizer are in a narrow band.The method of application that places at least one-inch of soil between the two is satisfactory.

No-till planting of soybeans raises questions about fertilization.They are not mobile in soils.Broadcasting applications in no-till systems can be questioned.A substitute would be to plant on top of the band below the soil surface.

The results of research done at the West-Central Research and Outreach Center in Morris show that yield responses tophosphate fertilization in no-till production systems are the same for both banded and broadcast applications.Many no-till planting systems have adequate fertilization that takes place in the planting operation.

The risk of yield loss due to insufficient P or K can be mitigated by maintaining soil test values in the Medium to High range.

There is concern that soil test levels for either P or K will drop substantially if low rates of phosphate or potash are applied year after year and soils are not tested frequently enough to make adjustments for decreasing soils test values.P and K may be applied based on crop removal.Table 6 shows the average removal of P and K for corn.

The higher the rate of P or K applied, the lower the crop value will be.Only applying what is needed year-to-year is the most economical way to use P and K.The build-and-maintain method is not superior to the sufficiency approach for P and K management.

Strict crop removal may not be enough for soils that test very low for either P or K.Extra P can be applied to build soils that are Medium or High.

The rule of thumb is that 16-18 lbs.P2O5 and 7 to 10 lbs.The Bray-P1 or Ammonia K tests need to be increased by 1 ppm.The amount of P or K needed to build the test depends on the soil's chemical properties.

The rates of fertilization suggested in Tables 4 and 5 should slowly build soils to the medium category beyond which P or K can be used to maintain or build soil test values.

Because of the reaction of ortho-phosphate with calcium, soil test P values will not be cost effective in western Minnesota.It is recommended to only apply what the crop needs to maximize yield potential.

The risk for P loss to the environment is increased by excessive building of P.The optimum range for crop removal-based maintenance is within the medium to high STP categories.The strategy suggests drawing STP down using P application in order to maintain it in a more profitable zone.

It is not possible to build and maintain high pH soils with the soil test P ranges.There is an example in Table 7 that could be used for K.It's important to collect samples at the same time to evaluate maintenance-based strategies.

The yield data collected from combines with yield monitors makes it easy to calculate the amount of nitrogen in the crop on a yearly basis.It is not recommended to use the previous years yield map to create a P or K application map because of the high cost of P and K, low probability of a profitable return on investment in medium and high P testing soils, and uncertainty as to the exact removal of nutrients per bushel of corn

A long-term average yield should be used.Recent long-term research shows that P and K will build over time in the top six inches of soil when exact removal of the nutrients is applied.

When nofertilizer is applied, soil tests will decrease.According to research in Minnesota, soil test levels do not decrease quickly if nofertilizer is applied.The Bray-P1 test will decrease over time.

It is possible that soil test decreases can be greater due to some environmental factors.When evaluating trends in soil test values over time, it's important to have multiple sampling in the same area.

It is important to consider the timing of the application ofphosphate.Many farmers apply P or K for the next crop in order to save on application costs.

As long as the rate of P or K applied to the preceding crop is sufficient for both crops, it's okay to apply it directly ahead of the soybean crop.There are situations where P can be quickly tied up.If you apply P directly ahead of the soybean crop, it is more likely that the crop will respond.

Ifphosphate is recommended and applied to soybean for fields with a pH of 7.4 or higher, thefertilizer should be applied in the spring before planting.The time interval for contact between soil andfertilizer will be reduced by this practice.The tie-up of phosphorus will be reduced and the soybean plant will use the applied phosphate more efficiently.

The timing of P application is more important for corn than for soybean.If the correct amount of fertilization is applied, application of P ahead of corn can be effective at maintaining high yield levels for both crops.

50% of Cl- by weight can be found in the form of KCl, which is commonly applied as thefertilizer.In the southern United States, high levels of chloride in the soil can affect yield.

Recent research has shown a tendency to build chloride in some Minnesota soils, which can potentially reduce soybean grain yield.The potential for yield reductions due to Cl- is tied to seasonal rainfall with a reduced impact occurring in years with above-normal rainfall.

There is little known about the tolerance of northern soybean varieties.In areas of western Minnesota, research has shown that soybean grain yield tends to be higher when KCl is applied ahead of corn.

There was no long-term impact of K application timing in central and eastern Minnesota.In most areas of Minnesota, there are small reductions in yield when more than 100 lbs of KCl is applied directly to the soybean crop.

If K is needed for soybean production on soils that can build, no more than 100 lbs of KCl should be applied per acre in the fall or spring directly ahead of the crop.

Recent research on medium- and fine-textured soils in Minnesota led to the revision of the guidelines.The guideline rates are not adjusted based on a soil's ability to hold potassium on cation exchange sites of clays.

The clay and cation exchange capacity of coarse-textured soils is very low.It is possible to waste Kfertilizer and reduce the economic return on the costs.There is ongoing research in Minnesota to determine if K guidelines need to change.Studies show that sandy soils need less fertilization than medium- and fine-textured soils with the same soil test K level.

Building soil test K greater than 120 parts per million is not recommended due to the low critical level of the soils.If more research data is available, Kfertilizer can be applied on low CEC soils.The use of this equation will reduce K application rates on low CEC soils and should be done on a trial basis to ensure that K is not limiting yield on irrigated soy grown on sandy soils.

The use of sulfur in Minnesota has been evaluated.Increased plant growth may respond to sulfur application, but yields were never increased or decreased.Under the following circumstances, sulfur is only suggested.

There are limited circumstances in which an application of 10 lbs of S as sulfate may be justified.If sulfur sulfate is carried over from a previous application, it will be enough to achieve maximum yield.

The application of sulfur in excess of soybean needs has been shown to increase sulfur containing cysteine and methionine, but not the total amount of protein concentration.

Sometimes soybeans grow on fields with a pH of 7.4 or higher and die.Iron deficiency chlorosis is a condition.There is no shortage of iron in the soil.The amount of iron that is needed for normal growth and development is not being taken up by the soybean plant because of soil and/or environmental conditions.

There is no easy solution to iron chlorosis.Management practices can be used to reduce the severity.

Variety selection is important.The University of Minnesota publication "Varietal Trials for Farm Crops" has chlorosis scores for many varieties.Most of the companies that market soybean seed give chlorosis scores for their varieties.

If the plant is not stressed, damage can be reduced.There are a number of factors that can affect soybean plants.

The factors that place stress on the soybean plant need to be eliminated as much as possible.The presence of chlorosis in less tolerant varieties has been found to be increased by nitrate carried over from previous crops.

Current research shows that an application of 1-2 lbs of EDDHA-Fe is enough to increase yields.The active ingredient is directly on the seed.

An oat companion cropseeded prior to planting at a rate of 1.5 bushels per acre and killed at 10 inches height has been shown to benefit soybean by reducingIDC for severely affected field areas.

It is recommended that growers in affected areas plant a tolerant variety and use either EDDHA-Fe or an oat companion crop.The University of Minnesota has a publication called "Managing Iron Deficiency Chlorosis in Soybean".

There is research that shows a link between glyphosate tolerant soybeans and possible deficiencies.The soybean crop does not respond to the application of magnesium, zinc, or copper according to research trials conducted in Minnesota.Adding these nutrients to a program is not recommended.

Plant tissue analysis can help determine whether to apply in-season foliar nutrients.Boron is often noted as potentially deficient in crops.

With broadcast application rates as low as two lbs B per acre, toxicity symptoms can show up with a low tolerance to boron application.There wasn't a positive benefit to applying boron to soybean.If application rates are too high, boron is more likely to reduce yield.

In some areas of the U.S., soils have traditionally been low in Mn.There is not a widespread need for the application in Minnesota.

Recent data shows that soybean can be grown on soils with a pH greater than 7.4 and a DTPA soil Mn test, from a 0-6” soil depth.There is an application of 10 lbs.It may be necessary to broadcast per acre.Foliar application of Mn should be done on a trial basis.There wasn't a consistent benefit to the application of Mn to soybean from research on more acidic soils.

The University of Minnesota suggests planting and Fertilizing a deer food plot.

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