20 Jan 2012
December 10, 2013 – Considering Growing Soybeans? Check Your Soil pH
Soybean is a crop that can display iron (Fe) deficiency on high pH (> 8.2) soils more than many other crops. Extensive research on this topic has been done in the Red River Valley of eastern North Dakota. Fe deficiencies are usually indicated by chlorosis (yellowing) of younger growth. Research by Dr. R. Jay Goos at North Dakota State University has shown that growing varieties more tolerant of the high pH soil conditions is the most effective way to manage Fe deficiency of soybean on these high pH soils. His research also showed some benefits from using applications of Fe containing foliar fertilizers, and or Fe containing seed treatments, but these methods were less effective compared to planting soybean varieties more tolerant of Fe deficiency (Goos and Johnson, 2000). You may not farm in the Red River valley of eastern North Dakota or southern Manitoba, but on many farms in the Northern Great Plains you might have portions of your fields with high soil pH, for examples on eroded hilltops. If these eroded, high pH areas are a significant part of your overall fields you might consider finding out which soybean varieties are more Fe deficiency tolerant, or consider adding in some foliar Fe fertilizer into the spray tank, at the time of in-crop herbicide applications.
December 1, 2013 – It is Important to Know the Previous Crop when Deciding on Nitrogen Fertilizer Rates.
If you grew a pulse crop (e.g., soybean, lentils or field pea) the previous year, chances are you should have slightly more available N for the following crop, compared to if you had grown a cereal crop. This is because the C:N ratio of pulse crop residues (e.g., 20:1) is lower compared to a cereal crop (e.g., wheat straw 80:1, and corn stover 60:1). In many states and provinces in the Northern Great Plains, an N credit is considered after growing a pulse crop. For example about 1 lb N/A for each bu of pulse crop yield. So if a 40 bu pulse crop was grown, there could be 40 lb of available N to be mineralized out of the pulse residues, for the following cereal crop. This can result in slightly lower N rates compared to planting a cereal crop into cereal crop residue (e.g., corn into corn residue).
November 20, 2013 – Relying on Nutrient Deficiency Symptoms before Taking Corrective Action May lead to Yield Loss
It is better to have an indication of a potential nutrient deficiency from fall or early spring sampling soil test results, than to wait until a deficiency is observed in a growing crop. This is especially so for less mobile macronutrients such as P and K, where in-crop applications rarely result in yield increases. There is a better chance to correct N and S deficiencies with an early in-crop application. But even for N and S the additional fertilizer should be applied before stem elongation stage of crop growth.
November 10, 2013 – How does the Multiple Freeze Thaw Cycles Experienced During the Winter and Spring Period in the Northern Great Plains Affect Nitrogen Release from Crop Residues?
Generally, plant-available soil N will be higher in the spring than in the previous fall. This is because the freeze thaw action in fields tends to help break apart crop residue particles, and soil organic matter, plus kill off some of the soil microbe population. All of this results in a flurry of renewed microbial growth and decomposition of organic materials resulting in a release of available N. It is important to understand this when comparing soil test N level results from a fall soil sampling to a spring soil sampling. Often the spring sampling may have 10 to 20 more lb of available N/A. Keep this in mind when deciding on your N fertilizer rates for a field next year. The field sampled in the fall will probably have slightly more available N come springtime.
November 1, 2013 – Your Neighbor Asks if You Want Manure from His or Her Cattle Feedlot, Applied to Your Fields.
Before accepting manure onto your fields it is important to know the properties of the manure. This can be best determined by analyzing a representative sample from the manure. One of the properties vitally important is the average carbon to nitrogen ratio (C:N) of the manure. This can be greatly affected by what type and how much bedding has been used. For example, I was asked in the summer of 2002 to visit a few poor growth fields of barley in central British Columbia, while I was visiting with a fertilizer dealer agronomist there. The farmer said he was disappointed in the growth of the barley crop on the fields. The fields displayed N deficiency. We asked what rate of N was applied. The farmer said around 80 lb N/A, reasonable for the area, but then also mentioned he had applied 20 tons/A of feedlot manure. He thought that with the applied N as urea fertilizer, plus the feedlot manure the crop should have had plenty of N. We asked what type of bedding was used in the feedlot. Because of the local lumber mills, they used sawdust for bedding. This was great for cattle health as sawdust is an excellent a bedding material to absorb moisture, but the C:N ratio of spruce wood sawdust is about 1000:1, compared to a wheat straw having a C:N ratio of 80:1. The sawdust bedding would tie up about 12.5 times as much N compared to wheat straw if it composed the same proportion of the manure applied to fields. We recommended he top-dress additional N onto the barley fields to correct the N deficiency.
October 20, 2013 – A Soil Property that Indicates How Much Nutrient a Soil Can Store is Called Cation Exchange Capacity (CEC).
CEC is a measure of what volume of positively charged cations such as calcium (Ca2+), magnesium (Mg2+), potassium (K+), sodium (Na+), and hydrogen (H+) a soil can retain. It is described in units of milliequivalents per 100 g of soil (meq/100g). It is greatly affected by the content of clay particles in a soil, the type of clay, and also the level of organic matter in the soil. The following table gives general CEC ranges for various soil textural classes.
Table 1. Typical CEC (meq/100 g) of Some Soil Textural Classes
Typical CEC Range
|Sand and Loamy Sand|
|Clay and Clay Loam|
A generally accepted formula for calculating CEC if you know the percent clay content and soil organic matter content is as follows:
CEC = 0.5 x % clay + 2 x % O.M.
For example if a soil had a clay content of 10%, and a soil organic matter content of 5%, the CEC could be estimated as = (0.5 x 10) + 2 x 5. The calculated value for CEC is 15. Generally speaking a soil with a higher CEC has greater inherent fertility and will require less additional fertilizer than a soil with a lower CEC. Usually CEC can’t be altered significantly but it is useful to know the CEC of a soil to help you know the natural soil fertility of a soil.
October 10, 2013 – When was the Last Time You Checked the pH of Your Soils?
Most crops grow best at a so-called neutral pH, generally between pH 6.5 to pH 7.2. If your soil pH has gradually acidified to below pH 5.5 or lower you can apply agricultural lime, mix it into the topsoil, and raise the soil topsoil pH into the neutral pH range. This generally improves nutrient availability and crop growth. The best way to check soil pH is to have soil samples taken from your selected fields and analyzed at a soil test laboratory. Most laboratories can also do a test to determine how much lime to apply to raise the soil pH up to a more neutral level. This is called a lime requirement test.
If your soil has an inherently high pH, for example 8.2 or even up to 9.0, it is possible to apply fine particle size elemental S and mix it into the topsoil to lower the pH. As soil microbes oxidize the elemental S, sulfuric acid is produced and the release of hydrogen ions (H+) lowers soil pH. This process can be done in much the same way as using agricultural lime to raise the pH, however this acidification of soil using elemental S tends to be excessively costly on a field basis and is used more in horticultural applications on smaller fields for high value crops, or for container grown plants that require low pH or acidic soil conditions. For most field crops it is more economic to grow crops more tolerant of high pH, and or apply required nutrients to a crop that are more available under high pH soil conditions.
October 1, 2013 – Taking Care of Soil Microbes Helps Crops Grow Better.
Many soil microbes help crops obtain necessary nutrients, so management practices that encourage microbial growth usually improve crop growth. For example, Rhizobium species bacteria form nodules on legume crops and fix N for the legumes from N gas in the air. Mycorrhizal fungi grow into many crop species roots, while extending their branches (hyphae) out into portions of the soil where roots don’t reach. This effectively increases the rooting exposure to more of the soil mass, and helps supply P and other plant nutrients to crops. Most soil microbes do better in soils where crop rotations, along with residue conserving management, return higher quantities of crop residues to the soil. In the longer term this helps to gradually increase soil organic matter content to an improved level. Higher soil organic matter content is beneficial to soil microbes and subsequently to the crops grown in the soil.
September 20, 2013 – How long has it been since you had soil sampling done on some of your fields?
Having soil samples taken and analyzed from your fields is one of the best methods to monitor plant nutrient availability for next years crop, and help determine the optimum rates of fertilizer you will apply. It is advised to have samples done at least once every three years, especially to monitor P and K availability. It can be useful to sample more often if you are concerned about N levels. If it has been more than five years since soil samples have been taken, or you are growing different crops in rotation, or recently you are growing higher yielding crop varieties, it may be time to have soil sampling done.
September 10, 2013 – When is the best time to take soil samples?
Usually in the Northern Great Plains region it is advised that soil sampling be done after harvest from mid fall to early winter, or when freeze-up occurs. By this time soil temperatures have cooled sufficiently so there will be little change in mineralized N levels. For most of the other nutrients, P, K, and S, etc. you could soil sample almost any time of the year, but for convenience the fall after crops are all harvested field access is best. Also most falls tend to be a time of the year when we receive lower amounts of precipitation and travelling over field with trucks equipped with hydraulic soils samplers is possible. Early spring is also an excellent time to take soil samples, but spring time tends to be more hectic, fields can be to wet to drive on. Also if you have soil sampling results available in late fall you have all winter to look over the analysis results and decide about next years fertilizer rates. Having made fertilizer rate decisions in the late fall or early winter you can arrange your fertilizer purchases and deliveries from your local fertilizer dealer.
September 1, 2013 – Does weed growth in the fall remove nutrients from next years crop?
It all depends on how much weed growth there is. For example if you harvested a winter wheat crop in late July, and you had warm and moist weather from after harvest until well into the fall, there could be lots of weed growth. This weed growth could take up and immobilize considerable amounts of nutrients. These nutrients are not lost, but could be tied up and less available for next years crop, until the weed residues are decomposed. To reduce weed use of nutrients you may choose to either cultivate a field, or spray weeds with a non-selective herbicide in the early fall, e.g. the first week of September.
August 20, 2013 – Mycorrhizal fungi an important friend to most crops
Many of our crop plants rely on a symbiotic relationship with soil fungi called mycorrhiza to grow well. Mycorrhiza are soil-inhabiting fungi that colonize crop roots by growing into or on the outside of plant root cells. They have been shown to more effectively dissolve some insoluble plant nutrients in soils compared to plant roots themselves. The mycorrhiza use these nutrients for their own growth and also share the nutrients with the crop plants. The crop in turn shares photosynthetic sugars with the fungi and this helps the fungi grow better. An example is mycorrhiza that help crops such as wheat, soybean, corn, flax, and peas obtain additional phosphorus from soils. The fungal hyphae or strands go out from the crop roots into the soil where roots aren’t growing and this effectively increases access to more parts of the soil or increases rooting area. Some crops are not hosts for the mycorrhiza and are called non-mycorrhizal crops. Canola is a non-mycorrhizal crop, and sometimes after canola is grown the following mycorrhizal host crop may show early growing season P deficiencies until a healthy mycorrhizal hyphae network is re-established in the soil. There have been attempts to grow the mycorrhiza commercially and apply it as inoculants to crops. This has had limited success, but research continues.
August 10, 2013 – Plant growth promoting bacteria
Bacteria living near or on crop roots can benefit crop growth. Normally the first soil bacteria thought of as beneficial to crops are the Rhizobia species of bacteria that live in the root nodules of legume crops and supply nitrogen to those crops. However, there are other bacteria that can help crops. These are bacteria that live in the soil near roots (rhizosphere) and have been shown to help plants by enhancing root absorption of nutrients, produce plant growth enhancing hormones, or by controlling antagonistic root fungal organisms. There have been attempts to develop commercial inoculants of some rhizosphere bacteria that you could treat crop seed with and the bacteria will multiply and grow in the rhizosphere and improve crop growth. However, many attempts have worked well in greenhouse trials but not well in field trials. If you are approached to purchase and use one of these products ask for field research results, hopefully close to your cropping region, done by third party researchers at a university or government research station, that show significant benefits to the crops you grow.
August 1, 2013 – Crop roots help feed soil microbes
We usually think of crop roots as absorbing water and nutrients for plant use, but roots are also an important food source for soil microbes that live in the soil near the roots (rhizosphere). As a plant grows some of the photosynthetic products (e.g. sugars) are moved from leaves down into the roots to nourish the roots, but a portion of these sugars are leaked out of the roots and nourish soil microbes including bacteria, fungi and actinomycetes. In most cases these soil microbes live in a friendly co-existence with the plant. The sugars also act as an energy source to help the soil microbes decompose previous crop residues and soil humus. After crops reach maturity and are harvested the dead crop roots become an additional food source for the soil microbes.
July 20, 2013 – Have you considered planting winter wheat on a field where you planned to plant a spring crop, but couldn’t because of excess spring rains?
If a field was left unplanted to your regular spring planted crop because of excess spring rains, consider planting winter wheat on that field in the early fall as an option. You can prepare for planting the wheat by controlling weed growth on the field during the summer after the field dries up sufficiently. Check with your local agriculture retail dealer or seed grower for winter wheat varieties well suited and available for your area. There has been good progress made developing high yielding and winter hardy winter wheat varieties for much of the southern portions of the Northern Great Plains.
July 10, 2013 – What happens to the nutrients on land fertilized but not planted because of excess moisture?
It is unfortunate to have applied fertilizer to part of a field and then be prevented from planting a crop because of excess spring rains. There is often concern that the nutrients applied may be lost. It depends on whether or not wet conditions persist and the nutrient in question. For the less mobile nutrients P and K there is little chance of losing these nutrients. Although if P and K was surface broadcast and not incorporated some losses may occur from granules being dissolved and some soluble P and K being lost in surface runoff water. If incorporated or subsurface banded both P and K will react with soil and losses are very minimal. P reacts with soil cations such as calcium and magnesium forming low solubility compounds, or with soil organic humus again becoming less mobile. Potassium is strongly attracted to clay particles and is retained on or between clay and clay particle layers in the soil.
Both N and S do have more potential to remain dissolved in soil water and be lost due to leaching down through the soil, or become lost as gaseous forms if wet conditions persist. Under wet conditions soil microbes become oxygen starved due to the soil pores being filled with water and having little air. Under these low oxygen conditions they will source oxygen first off nitrate ions and then sulfate ions. The nitrate can be lost as N2 or N2O gases, while sulfate can be lost as H2S gas. Normally N losses are much more prevalent than S losses. It is difficult to know exactly how much of the N and S is lost from a soil. You can take soil samples in the fall or following spring, after the wet affected areas dry up, and have a soil test laboratory analyze for nitrate and sulfate levels in the soil. This will give you an indication how much of the applied N and S fertilizer remains.
July 1, 2013 – Management options for land too wet, too long to be planted
In springs with excess rainfall there are low lying portions of fields that are too wet, for too long to allow planting of regular crops. But after the areas dry up later in the spring and summer, there are a couple of options for what can be done so they don’t turn into weedy patches. Weed control is advised to prevent build up of weed seeds in the soil. One is to fallow the area using either tillage, or a non-selective herbicide, or a combination of tillage and non-selective herbicide. Another is to plant a later seeded cover crop once the areas are dry enough to allow access with equipment. This cover crop, e.g. oats, can be used as a green feed crop for hay, or terminated in the early fall using tillage or a non-selective herbicide.
June 20, 2013 – Which major plant nutrients should be considered for a top-dressing application?
If significant portions of a field are diagnosed with a nutrient deficiency at an early stage of crop growth, for example before stem elongation, a decision will be made whether or not to consider an in-crop application to try to correct the deficiency. Of the major plant nutrients, namely N, P, K and S, it is possible to correct N and S deficiencies but much less possible to correct P and K deficiencies. Both N and S are mobile in the soil, and as long as sufficient moisture is received after applying the fertilizer, it should move to plant roots and the crop’s N or S status should improve. Both P and K are so slowly mobile in the soil that an in-crop rescue application for a P or K deficiency is usually not effective. Usually the better strategy is to make plans to supply sufficient P and K for future crops.
June 10, 2013 – Don’t forget rate when applying a micronutrient.
There are many ways to apply a needed micronutrient for a crop. You can apply a granular or liquid product as part of a pre-plant broadcast and incorporate or banded blend, or a powder seed-dressing, or a granular product included in a dry seed-row or side-banded blend at planting, or a liquid product in a liquid seed-row or side-banded blend at planting, or lastly a post-emergent foliar liquid application. Some people claim one method is more effective than another. However it is important to make sure the rate of micronutrient applied is sufficient to supply the amount of micronutrient needed by the crop. One of the methods described above may be a bit more effective than another, but if the actual rate applied is too low it doesn’t matter how effective the method of application is, the crop needs to absorb sufficient amount of the nutrient to improve crop growth.
June 1, 2013 – Many field tours occur in late June or July, so check dates and locations
I like taking the opportunity to attend summer field days at research centers, or field tours organized by grower commodity organizations. There is useful information presented about new crop varieties and new cropping technologies. It is worth the time to check the websites or newsletters of local ag-extension centers, or grower organizations, to find out the scheduled dates of field days or tours in your area. You usually cannot attend all of the events you would like, but it is disappointing to hear about a tour you would of liked to attend but didn’t know about it until after it happened.
May 20, 2013 – Plant analysis and soil testing
When scouting fields after crop emergence a farmer or crop adviser will notice patches of poorer growth compared to the rest of the field. One of the purposes of crop scouting is look at these poorer growth areas and determine what might be the cause of reduced growth. The cause may be an infestation of weeds, insects, a fungal disease, or a nutrient deficiency. If after initial investigation the adverse effects of weeds, insects or fungal disease are ruled out and a nutrient deficiency is suspected, it is important to further investigate effectively. It is suggested that notes and photographic images be taken of visual differences between poor growth and good growth areas. Also it is useful to take plant and soil samples from both the poor growth and good growth areas. These samples can be sent to a soil and plant test laboratory for analysis. Usually by having both soil and plant analyses it is easier to determine if a nutrient is lacking, compared to just having plant analysis results.
May 10, 2013 – The acres planted to canola in the Northern Great Plains region (NGP) increased to all time highs in 2012.
The acres planted to canola continue to increase in all provinces and states in the NGP. This has resulted in total acres in the NGP going from 13,205,000 acres in year 2000 up to the all time high of 22,491,000 acres in 2012. Canola consumes more S per bushel of harvested grain compared to cereal crops. Wheat for example uses 1 lb of S for every 10 lb of N. In contrast canola uses 1 lb of S for every 6 lb N applied. If an average N rate of 80 lb N/A is applied to both wheat or canola, a canola crop would require 13.3 lb S compared to 8 lb S for the wheat crop. If you are growing more canola on your farm you will need to apply more S fertilizer to satisfy the S needs of this crop.
May 1, 2013 – Potassium for soybean and pulse crops
If you haven’t ever grown soybeans or pulse crops (dry peas, dry beans, lentils or chickpeas) and you want to include them in your crop rotation, you may need to consider applying higher rates of K in your fertilizer blends. For example if you compare wheat to dry peas or soybean at the equivalent 50 bu/A yields, the amount of K removed with the harvested grain is respectively 17, 30 and 65 lb of K2O/A for wheat, dry peas and soybeans. More soybeans or pulse crops in your rotations means more removal of K. Applying potash (KCl, 0-0-60) is an excellent way to supply needed K.
April 20, 2013 – If you grow a new higher yielding variety or hybrid, you may need to increase your fertilizer rate.
If you treat a high yielding crop like a lower yielding crop you may just get a low yield. I’ve seen situations where a farmer has switched from a lower potential yielding hybrid to a higher yielding hybrid but didn’t increase the fertilizer rates applied and ended up with disappointing yields. If a new variety or hybrid has been recently introduced to your area, check with farmers or seed company representatives who have experience with the new variety or hybrid to know what fertilizer and management practices are used to exploit the greater yield potential.
April 10, 2013 – If droughty conditions were experienced last year and spring soil moisture is low at planting, what is a reasonable strategy for fertilizer rates?
Many farmers will have a tendency to reduce all fertilizer nutrient rates after dry conditions the previous year. However a contingency plan should be considered if moisture conditions improve significantly early in the growing season. For example it is advised that P and K rates remain close to regular rates just in case moisture conditions improve, as it is difficult to supply additional amounts of these two nutrients as an in-crop application. However, N and S can be successfully top-dressed if ample post-planting rainfall is received. Discussion should be done with your local retail fertilizer dealer to determine if you will be able to access N and S fertilizers for top-dressing if needed.
April 1, 2013 – Excess seed-row fertilizer can reduce plant stands, delay maturity, and sometimes reduce yields.
Seed-row fertilizer can be an effective way to apply required nutrients to a crop, however there should be caution that the rate of the fertilizer applied isn’t excessive. If too high a rate is applied there can be fertilizer salt injury. Also, if the N rate is too high using urea as an N source, or an ammonium containing N source under higher soil pH conditions (e.g. pH 7.5 or higher), the generation of free ammonia (NH3) can cause ammonia toxicity to germinating seeds and seedlings. Either way excess salt injury or excess ammonia concentrations can kill or delay germinating seeds and seedlings. Check with your local agronomist or crop adviser for advice so that adequate but safe rates of seed-row fertilizer can be applied considering your planter design, row spacing and local soil conditions.
March 20, 2013 – Are crop-sensing technologies, an improved way to decide how much N to top-dress or not?
The development of crop sensing technologies, using Normalized Difference Vegetation Index (NDVI), are now commercially available and are being used by more farmers each year. The technology gives a reading, that when used with crop specific calibration curves developed through field research, gives a reliable estimate of crop biomass, N status, and yield potential. What many farmers do is put down a base N application, e.g. 60% of normal rates, and then early enough in the crop life cycle (e.g. V8 growth stage in corn, stem elongation in wheat, and bolting in canola), will run over a field with a top-dress UAN applicator equipped with NDVI sensors. The sensors are connected to a variable rate UAN control system. If the crop in an area of the field is low in N, indicated by a light green as opposed to dark green color, additional N is applied on the go using real time variable rate equipment. If an area of the field has abundant residual N, the crop color and growth is excellent, then no additional N is applied. Research using this technology has shown that overall crop yields can be just as good, and sometimes better compared to regular blanket N applications rates. Often overall field amounts of N are reduced somewhat, and overall field yields are increased, this covers the extra cost of using the NDVI technology and variable rate N equipment. I suggest you do an internet search for GreenSeeker or Crop Circle and learn more about this type of technology.
March 10, 2013 – Spring soil testing, a good way to see how the dry conditions last year affected your soil residual nutrients.
I have had many questions about the effect of the 2012 drought on soil residual plant nutrients in 2013. In summary, you may have more residual N in your soil than normal, but there will not be much observable effect on residual P and K. This is because the N use and loss mechanisms of crop uptake, leaching and denitrification are reduced greatly when there is drought causing dry soil conditions. Soil test levels of P and K are much less affected and the usual soil reaction effects on P and K proceed forward even under drier conditions, plus P and K availability is much more a multi-year effect, and one year of drought will not show large differences in soil test P and K availability. The best way to know how much residual N is in your fields is to have some soil sampling done and have the soils tested for plant available N early in spring of 2013, before you decide on N rates for the 2013 crop. You may find that higher residual N levels justify a moderate reduction in N application rates for your 2013 crop.
March 1, 2013 – Are there fertilizer additives that might be useful for your crops?
The N fertilizers we have available for farm use have been around for decades, for example, anhydrous ammonia (AA), urea, and urea ammonium nitrate (UAN). Are there any new N fertilizers, or fertilizer additives that can be used to increase fertilizer use efficiency, especially when weather conditions are such that losses of N can happen? Yes there are.
One example is a group of N fertilizers called controlled release ureas. The urea granules are coated with a polymer coating that allows moisture into the granule to dissolve the urea, and the urea solution is released into soil gradually based on moisture and temperature effects. That is a warmer temperature with adequate moisture, results in faster release. These types of modified urea fertilizers are useful to reduce leaching and denitrification losses of the N fertilizer if heavy rains are received early in a growing season before crops have had a chance to take up the N.
Another example is N fertilizers that are treated with so-called stabilizing additives. For example a urease inhibitor additive used for urea and UAN can slow down the breakdown or hydrolysis of the urea molecule by the natural soil occurring urease enzyme. This is a useful additive to reduce ammonia volatilization losses for surface applied urea or UAN, if sufficient precipitation after broadcast surface application is not received. Lastly, a second group of additives are called nitrification inhibitors. These slow down the conversion of ammonium forms of N (anhydrous ammonia, urea and UAN) to nitrite and subsequently nitrate N. This can reduce dentrification losses of nitrate under saturated soil conditions.
You can ask your local retail agronomist if you might benefit from using some of these new N fertilizers or additives.
February20, 2013 – Do you know what a Brown Soil Moisture Probe is?
Drought in parts of Montana is not a new or uncommon experience, and unfortunately was experienced severely in the south half of Montana in 2012. For that reason, there are dryland areas where farmers use summer fallowing as a method to conserve moisture and increase the chance of growing an adequate yielding crop, even though a crop on a specific field may be grown only once every two years. Summer fallowing is where a crop is not grown for a year, weed and volunteer crop plant growth is controlled by tillage, or unselective herbicide applications to reduce plant transpiration losses of water. Precipitation received during the fallow year builds up in the soil profile and helps to fill the moisture needs of crop grown the year after summer fallowing. One disadvantage of having a set fallow-crop two year rotation is that there are some years when ample moisture is received after harvest through the fall, winter and early spring, prior to the summer fallow period and there is no need to conserve moisture to grow a good crop. Dr. Paul Brown, an agricultural researcher in Montana, developed a soil probe tool, in the 1960s, to assess how much moisture was stored in a soil in early spring (see Brown and Carlson 1990). It is called the Brown Soil Moisture probe, after Dr. Brown. It is a T-handled soil probe consisting of a steel rod (e.g. 3/8” diameter), with a slightly larger ball bearing (e.g. ½“ diameter) welded on the end pushed into the ground. When pushed into a thawed soil in early spring it will go downward through moist soil, until you hit dry soil and then stops. By using an estimate of soil texture (percent of sand, silt and clay respectively, e.g. silt loam soil) the amount of moisture stored in a soil can be estimated. If the depth of moist soil is enough, to represent sufficient soil moisture that when combined with average precipitation for the area could grow a decent yielding crop, a farmer may decide to plant a crop rather than summer fallow that year. There are areas affected by drought in the year 2012 where farmers may consider summer fallowing some fields in the crop year 2013. Use of a Brown Soil Moisture Probe may help them gather information to decide whether or not to plant a crop or summer fallow in 2013.
Reference: Brown, Paul L., and G.R. Carlson, Grain Yields Related to Stored Soil Water and Growing Season Rainfall.. Montana State University, Agricultural Special Report 35, November 1990.
February10, 2013 – Time in your heated shop maintaining your planting equipment in the winter, can be a good investment of your time.
Discovering that your planting equipment needs an overall replacement of major bearings, or soil engaging disks or hoe openers, or installation of a new starter fertilizer kit, just before or during prime planting time in the spring can be frustrating and result in delayed planting and lower crop yields. Taking time in the winter to check over and replace worn planter parts, in the comfort of your heated shop, can have your equipment ready to go early in the spring.
February 1, 2013 – Consider the 4R Nutrient Management Principles when planning your fertilizer applications this coming year.
A set of useful nutrient management principles is being encouraged for farmer use. It is called 4R Nutrient Stewardship, and means that plant nutrients should be applied as the Right Source, at the Right Rate, Time, and Place. For each of your major fertilizer nutrients you should consider whether or not you could benefit by using a more effective source, rate, timing and placement, compared to what you presently use. The Right Source means that you apply a form of fertilizer that effectively supplies nutrients. The Right Rate means that you apply sufficient but not excessive amounts of a nutrient. The Right Time means that fertilizer is applied at a time so it is best available to the crop being grown. Lastly, Right Placement means that the fertilizer is placed in a location relative to the seed-row to maximize root interception and absorption. An example of this is to compare different ways of applying N to a winter wheat crop. Let’s say there are three N fertilizer sources locally available to a farmer, specifically anhydrous ammonia (82-0-0), granular urea (46-0-0) and liquid urea ammonium nitrate (28-0-0). Anhydrous ammonia can only be applied before or at planting of winter wheat, which would mean in the early fall. This is not a good time for an anhydrous ammonia application, as the ammonia will be converted almost totally over to nitrate (NO3-) before freeze-up and nitrate in the soil during spring thaw can be subject to denitrification losses. Urea can be surface broadcast applied effectively in late fall or early spring. UAN can be top-dressed effectively a bit later in the spring than urea because half of the N is in the ammonium or nitrate form, almost immediately available to the crop, and the remaining urea portion of UAN will be converted over to ammonium or other nitrate in time to be used by the crop. So a farmer will need to consider prices of urea compared to UAN, and also when is it most effective to apply N to the winter wheat crop. If a late fall or early spring application of urea, frees up valuable time later in the spring, then urea may be the right choice. But if the farmer is not rushed in the spring and UAN prices are competitive with urea prices, then UAN may be the right choice. This example of choosing the right source illustrates that there needs to be consideration for not only the Right Source, but also what are the Right Time and Placement for that source of fertilizer. Lastly, the Right Source, Time and Placement will have a big effect on how efficient the fertilizer is used, and can affect the Right Rate of N used. Using the 4R principles can help a farmer make better use of his or her fertilizer investment.
January 20, 2013 – How well did your nutrient management plans perform last year?
A useful practice is to do a calculation of nutrients applied compared to nutrients removed on your various crop fields. It is much the same as doing an audit of your financial records, e.g. funds deposited compared to funds spent. Generally for your major nutrient inputs, specifically N, P and K, you can determine whether you are lowering, maintaining, or gradually improving your soils fertility status. I recently discussed with one farmer in central Saskatchewan, how his fertilizer inputs compared to crop nutrient removals in harvested grain. In this instance sufficient N was being applied, so that N fertilizer inputs were equal to and slightly above protein N amounts in harvested grain. However, he had switched four years earlier, to a lower rate P and K program (respectively 8 lb P2O5/A and 0.7 lb K2O/A) using a liquid seed-row starter fertilizer, compared to his previous dry granular seed-row blend, normally containing 25 lb P2O5 and 10 lb K2O. His spring wheat crops yields had averaged about 40 bu/A over the past four years. This yield of wheat was removing about 23 lb P2O5/A and 17 lb K2O/A each year. So over the past four years there had been a net removal of 15 lb P2O5/A and 16 lb K2O/A each year. After looking at soil test results this past fall, they were quite low for plant available P on all fields tested, and K levels were moderate for the area. I suggested that P fertilizer rates be increased to greater than crop removals, e.g. 120% or 28 lb P2O5/A over the next four years in order to gradually improve P availability. For K, the input rates should be increased to at least close to crop removals, e.g. 17 lb lb K2O/A because the relatively younger glacial soils tend to be reasonably high in exchangeable K. I’m confident that when soil samples and test results are reviewed again four years from now, soil test levels of P and K will have increased, if closer to above crop removal amounts are applied.
January 10, 2013 – Farm meetings held in the winter, can be a great time to learn about new crop technologies.
Now is a good time to check with your local government agriculture extension office, your ag-retailer, or your crop commodity organizations, and find out when and where winter farm meetings are being held. There are always new technologies and products becoming available. This can include new crop hybrids or varieties, new herbicide, fungicide or insecticide formulations, new fertilizer forms or additives, and recent developments in planting and application equipment. By attending some winter meetings, you may hear about some new products that could help you grow higher yielding and increased quality crops. Some time invested in learning about new technologies useful for your farm, can pay a dividend in increased net returns.
January 1, 2013 – How important is snow as a source of moisture for next years crop?
After a dry summer and fall, snow received this winter will help build up soil moisture reserves for the next crop. There are a number of factors that determine whether or not snow will melt and infiltrate into the ground. One is if the soil is dry or moist when hard freezing comes in early winter. If topsoil is wet it will freeze solid and snow received during the winter will tend to run off rather than soak into the ground. However, since most areas in the Northern Great Plains (NGP) had a dry fall, topsoil was low in moisture, will not freeze as hard, and so any snow received this winter will have a better chance of soaking in. Another factor is how high the stubble was cut and remains from the previous crop. Taller stubble will trap and store more snow evenly over a field, and when spring thaw comes more of the melting snow will have a chance to soak into the ground. A third factor is how fast spring thaw is next spring. If temperatures remain cold until late winter and there is a very quick warming, more water from melting snow will run off. If spring thaw is more gradual, moisture infiltration will be greater.
December 20, 2012 – Why Consider Applying Fertilizer During Your Planting Operation?
Precision placement of side-banded fertilizer, or seed furrow starter fertilizer, during planting has often been shown to increase fertilizer uptake by crops and reduce use of fertilizer by weeds. It can also reduce reaction of applied nutrients with soil components (e.g. organic matter, clay particles, and exchangeable ions), and keep the fertilizer nutrients in a soluble form so crop roots can absorb them.
December 10, 2012 – If You Experience an Early and Open Spring, Consider Pre-Plant Applied Fertilizer.
Time is valuable in the spring. Generally the earlier you can plant within the normal planting window for your area, the greater your yields will be. If you experience an early and open spring season you might consider speeding up planting operations by pre-plant applying fertilizer earlier than normal. This provides extra time to get planting equipment ready, seed in place, and to begin planting as early as possible. Also, don’t forget to consider applying low rates of starter fertilizer in the seed furrow, depending on the specific crop tolerance, or side-banding an appropriate distance to the side and below the seed furrow depending on the root architecture of the specific crop. In most seasons, the earlier you plant, the greater the benefit from using starter fertilizer.
December 1, 2012 – Is One Form of P Better than Another?
The three main forms of P fertilizer available to farmers are granular monoammonium phosphate (11-52-0), granular diammonium phosphate (18-46-0), and liquid ammonium polyphosphate (10-34-0). All three of these P fertilizer forms supply a soluble and plant available P source for crop plants. Your choice of the one you use will depend on local market prices, availability from retail fertilizer dealers, and what fertilizer application equipment you have.
November 20, 2012 – Deciding on Fertilizer Rates in Times of Uncertain Weather
If you knew every year the available soil moisture content at planting, and the timings and amounts of rainfall in the growing season after planting, it would be much easier to decide on fertilizer rates. This is because you could accurately estimate what potential crop yields would be, and supply sufficient but not excessive supplemental nutrients using fertilizers. However, it is very difficult to accurately predict when and how much rain will be received. Normally most farmers plan for a good to slightly above average growing season, as far as rainfall and fertilize accordingly. But, if it is dry and looks like it will be a drier than normal year, lower than normal fertilizer rates may be appropriate. If more than average early season rains come however, there should be a contingency plan to top-dress the crop with additional N fertilizer to help achieve an increased yield potential.
November 10, 2012 – How Do You Determine a Realistic Target Yield for Your Crops?
Crop yield targets are something that can change over time. This is because of the following factors:
- · Higher yielding crop varieties or hybrids that result in greater potential yields.
· Improvements in weed, insect and disease control technologies resulting in higher yield potentials.
· Improved fertilizer technologies result in improved uptake of fertilizer nutrients by crops and less nutrient losses to the environment. This might include improved efficiency forms of fertilizers, use of fertilizer additives, or improved rate, time of application, and placement of fertilizers.
· Use of conservation cropping or reduced tillage methods that conserve valuable soil moisture and increase water available to crops. This applies to the more arid areas.
· Periods of less, or more than normal, precipitation amounts. If the deficit of moisture is severe and considered a drought, lower yield targets are appropriate. Conversely, if above normal, but not excessive, precipitation is received then higher than normal target yields could be used.
November 1, 2012 – What Methods are Available to Decide on the Rate of Fertilizer to Apply?
High yielding crops usually require supplemental nutrients, applied as fertilizer or manure, or a combination of fertilizers and manure. It has been estimated that over 40 to 50% of food produced annually in the world is because fertilization is used to increase crop yields and maintain soil fertility. There are a few methods farmers use to decide what rate of fertilizer to use.
- First, use rates developed by assessing what levels of plant available nutrients are in the soil using soil testing. By knowing what amount of nutrients will be supplied by the soil, it is possible to reach realistic yield targets for your area, by adding the appropriate rate of fertilizer nutrients to go along with nutrients available from the soil. The amount to add is usually determined by referring to fertilizer calibration results from field research done previously by state or provincial, and or university soil fertility researchers in your local area.
- Second, apply rates based on crop removals. This is done by knowing what crops usually yield in your area and the amount of fertilizer nutrients removed in harvested portions of the crops, on a continuing basis.
- Third, apply local area common rates of fertilizer used for various crops, taking normal crop yields into consideration.
October 20, 2012 – Are There Choices for the Type of Potassium You Apply?
The most common K fertilizer is potassium chloride (KCl) or potash, analysis 0-0-60, or 0-0-62; the next most widely used is potassium sulfate (K2SO4), analysis 0-0-50-17S; also potassium magnesium sulfate (KMgSO4) or sulfate of potash magnesia, analysis 0-0-22-22S-11Mg; and there is some potassium nitrate (KNO3) a manufactured source used in liquid fertilizer blends and as a N and K source for top-dressing some crops. KCl is the lowest cost form and works well for most crops except those that are sensitive to excess chloride, e.g some fruit and vine crops, where K2SO4 and KMgSO4 have a good fit.
October 10, 2012 – Which N Fertilizer is Good for Fall Application?
In the NGP there are three main forms of N fertilizer available to farmers, those being anhydrous ammonia (NH3), urea, and urea ammonium nitrate solution (UAN). Anhydrous ammonia is a popular N source for fall application. It needs to be injected into the soil, usually to a 4-inch depth, and the concentrated band of NH3 tends to stay in the ammonium (NH4+) form over the fall and winter and is less subject to denitrification losses if very wet soils occur in the spring. Urea can work quite well in the fall or spring, but equipment for fall banding is less available compared to equipment available for NH3. The majority of urea is banded either as a pre-plant, or side-banded at planting, or broadcast and incorporated by tillage prior to or during the planting operation. UAN is one-quarter nitrate N and is better suited to spring use, or in-crop side-dressing.
October 1, 2012 – What are the Advantages and Disadvantages of Fall Applied Fertilizer?
In the Northern Great Plains (NGP) fertilizing in the fall, especially with N, is quite common. There are a couple of main advantages compared to spring fertilizer applications. One, fall fertilizer prices are usually lower than spring prices, and secondly getting at least part of fertilization done in the fall leaves less product to handle and saves time in the spring. The one disadvantage is that if the fall and part of the early winter is open and warm most of the N gets converted over to the nitrate form and can be subject to denitrification losses, if wet saturated conditions occur in the spring. After droughty conditions in the southern portion of the NGP in 2012, especially in North Dakota and Montana, a wet spring might be considered a good thing.