Crops

Crop needs for secondary and micro nutrients are increasing

Written by Dr. Paul Tracy on .

Over the past few years, we have seen an increase in crop deficiencies for the big three (macro) nutrients-nitrogen, phosphorus and potassium. Reasons for those deficiencies have been a combination of high replacement costs and excellent crop yields that have increased nutrient removal. We have been pulling nutrients from the soil fertility bank account that took decades to build. That account is now depleted to the point that crop yields are suffering. Now that prices have stabilized, we are poised to reinvest in the temporarily stressed soil bank account.

As we shore-up traditional fertilizer programs, it is time to pay attention to the full spectrum of crop nutritional needs.

We generally refer to magnesium, calcium and sulfur as the secondary nutrients. They are described as secondary because they are needed in similar amounts as the macro nutrients, but their supplementation has been required less often because of adequate amounts supplied via the soil, atmosphere, other fertilizers, manures and agriculture limestone.

Ten steps to top forage production

Written by Dr. Paul Tracy on .

You can plan your way to better pasture and hay

Step 1: Natural resource inventory

Anyone who reads this column on a regular basis knows the importance that I place on building forage systems around the natural resources present on your farm/ranch. This should be the starting point for all forage production decisions.

A good place to start is soil type information that can be obtained from the Natural Resources Conservation Service. In fact, they have a “Pasture and Hayland Suitability Group” rating and an estimated yield production potential designation for each soil type.

Other natural resources to consider are hydrologic information, topography, non-forage vegetation and wildlife. There are numerous print and electronic resources available to obtain most of this information including the Natural Resources Conservation Service, Missouri CARES, and MFA’s Precision Agronomy Services.

Step 2: Current livestock inventory

Obviously, you should always know your current livestock inventory. Is it enough to meet your financial needs? Are you tracking, sourcing and verifying animals in a way helpful for planning future forage production needs? What are your current animal and forage levels? Do you need increased forage production to maintain the current animal numbers present? Generally speaking, improving forage production efficiency will decrease other inputs, stabilize winter feeding requirements and provide options for increasing animal numbers.

Step 3: Current forage species inventory

Each and every field needs a complete inventory of the forage species, weeds, brush, sprouts and trees present. This should be used as the starting point for maintenance, renovation or re-establishment of any species. Species inventory should be used in developing yield goals, total forage supplying capacity, grazing and harvest strategies and field modification prioritization.

Step 4: Future livestock goals

Before renovation or pasture improvement activities are initiated, future livestock goals need to be determined. In many cases, perennial forage establishment can take a few years to reach optimum production. A flexible five-year plan is usually about as far out as can be maintained. Not only do future livestock needs affect today’s renovation decisions, but they can also affect crop rotation sequences, especially if a kill-smother-kill renovation program using annual smother crops is required. I always emphasize targeting slightly higher goals compared to estimated on-farm forage needs. Extra forage can always be stored for future needs or sold. The 2009/10 year offers a prime example of the need to overestimate winter forage requirements. We went into last winter thinking we had more than adequate hay/silage supplies only to come up short long before spring greenup.

Step 5: Develop an accurate set of equipment needs

It is important to monitor the forage production capital needs of your operation. Careful planning of the vehicle, haying equipment, tractors, planters, storage, fencing, and watering requirements of your operation is very valuable. With the exception of a few rotational grazing purest programs, I am a firm believer in hay/silage production being a key component of any operation that utilizes on-farm forages.

One helpful hint is to try to estimate all farm supply, equipment and maintenance costs on a per acre basis. This is a real eye-opening exercise that will help prioritize forage production decisions.

Step 6: Forage species selection

This can be one of the toughest, yet most important components of a quality forage program. You have choices of perennials vs. annuals, grasses vs. legumes, warm season vs. cool season species, mixed stands vs. monocultures. My advice to growers is to use any and all of the above combinations based upon your needs, experiences and personal preferences. I firmly believe that planned diversity (either within field or between fields) is what separates the great forage producers from the good forage producers. To make the most out of your land resource base, try to diversify forage type or forage uses to stretch the grazing season to as many months as possible. An example of this is to pull animals off of tall fescue in the summer and put them on a warm season grass until as late in the fall as possible. The “rested” fescue fields can then be conditioned and fertilized properly in August to provide an excellent stockpiled forage resource base.

Step 7: Forage crop nutrition management

Crop nutrition is a critical component of any forage system. Hay removes much more nutrients than does pasture. Cool season crops require a different fertilizer application timing than do warm season crops. Soil pH adjustments vary appreciably among forage crops.

All forage nutrition programs should start with soil testing. Soil test recommendations are uniquely designed to address specific forage species needs. For multiple use fields, it is a very good idea to annually rotate hay fields and pasture fields. This will allow the animals to naturally redistribute nutrients across your farm/ranch.

Step 8: Forage integrated pest management

Many folks don’t feel forages require the pest control intensity compared to their row crop counterparts. In reality, weeds, insects and diseases cause millions of dollars in lost forage production across our region annually. Eliminating weed, brush and sprout competition in pastures alone can increase forage and beef production by over 50 percent. Insect control in high value hay crops like alfalfa saves millions of dollars in lost revenue annually. Disease control in forages is more preventative (variety selection) than reactionary (fungicide treatments). For example, WL Alfalfas offer a tremendous disease resistance package compared most other alfalfa varieties. In our environment, a good disease package often provides at least two years extended stand life.

Step 9: Forage harvest management

Harvest management plays a critical role in forage production, quality and persistence. With almost all forages, quality declines as the crop matures. For instance, tall fescue harvested in April/May will contain several percent higher protein content and 25 to 50 percent higher relative feed value compared to fescue harvested in June, July or August. Weather plays an important role in when crops can be harvested, but planned options like bagging the first cutting and species/harvest diversity limiting the total number of acres needed to be harvested at any one time goes a long way toward efficient harvest management.

Step 10: Farm record keeping

Keeping accurate records of all livestock activities is extremely important. Forage production is no exception. All inputs should be carefully recorded and tracked. I am not an economist, but estimating the cost per unit yield produced (hay, silage, beef, milt, etc.) should be recorded as accurate as possible. Keeping a record and budget can help tremendously when evaluating inputs to be made concerning all phases of future forage production management decisions.

I have provided a brief overview of a ten-step forage systems program. Each step contains hundreds of options, and only you can decide which are best for your location. The steps are not necessarily chronological and are certainly not mutually exclusive. In reality, they are completely intertwined and inseparable from each other. As always, best wishes in developing the best forage system possible, and don’t hesitate to contact us with questions, concerns or comment

Dr. Paul Tracy is director of agronomy for MFA Incorporated.

The 4 Rs of crop nutrition—the Right place

Written by Dr. Paul Tracy on .

The final installment in the 4 Rs series

Fertilizer placement can be discussed at two levels. The macro level involves placement based on in-field geographical locations. The micro level is based upon placement within the soil profile and in proximity to the growing crop.

There is no doubt that placing plant nutrients in the Right place on the landscape is one of the most cost effective management strategies. We have been variably applying nutrients across fields for over 15 years. The success of these programs has been tremendous, and I highly recommend the technology across most farming operations.

In terms of micro placement, there is no universal most efficient location. Agronomically, there are multiple factors when considering where to place crop nutrients.

The crop grown has a tremendous effect on plant food placement. With perennial crops like alfalfa and tall fescue, it is impractical to incorporate plant foods, so surface broadcast is appropriate. The one exception is immediately before crop establishment. Whenever possible, lime and fertilizer applications designed to raise soils to optimum levels should be followed by an incorporating tillage immediately prior to planting.

In row crops, there is tremendous diversity in terms of the most effective nutrient placement. We generally recommend completely different fertilizer nutrient placement strategies between corn and soybeans.

Corn has a fibrous root system that extracts nutrients differently than soybeans, which have a taproot system. Corn also tends to be planted earlier than soybeans, a time when cool/wet conditions slow soil nutrient release via mineralization or dissolution, and also slow root growth and subsequent interception of soil derived nutrients. For these reasons, corn responds more consistently to banded fertilizer than do soybeans.

Fertilizer bands tend to be more efficient than broadcast applications in no-till situations. Surface bands concentrate nutrients, thus leading to less potential tie-up on crop residues. Subsurface bands place nutrients deeper in the soil profile where it may be more accessible to plant roots, especially when dry conditions lead to restricted root activity near the surface.

Another practical reason for banding in corn compared to soybeans is the row widths involved. A general rule is that the bands can be spaced no more than two row widths apart. Corn is generally planted in wider rows than soybeans, thus making the equipment set-up, cost and application efficiencies for banding more economical.

Banded fertilizer is generally more efficient in low-testing compared to high-testing soils. This is because the higher concentration of fertilizer in the banded area slows the rate of fixation (tie-up) the soil has for the applied nutrients. Whereas, when soils already contain optimum nutrient levels, our fertilizer recommendations are based upon current crop removal replacement rates and the current season nutrient use efficiencies are not as crucial. It should be noted that banding fertilizer to improve efficiencies in low testing soils is almost always less effective and less economical than maintaining optimum soil nutrient test levels throughout the root zone.

Starter fertilizers are usually placed near the planted seed. This is because under cool-wet early growing season conditions, root growth to intercept banded nutrients and availability of soil nutrients is inhibited.

There are limits to the amount of fertilizer that can be placed near newly planted seed. Fertilizer salts and ammonia injury can occur in pop-up or in-furrow starter fertilizer systems. Therefore, the rule of thumb is no more than ten pounds of combined nitrogen, sulfur and potassium can be applied in-furrow.

I prefer that starter fertilizers be placed at least 2 inches beside and 2 inches below the planted seed. This safely allows much higher rates of nutrients and a more dependable rate for stimulating early season crop growth.

One placement system that is gaining attention is to apply anhydrous ammonia, phosphorus, potassium and desired micronutrients in a band sometime between the fall and early spring. Using RTK guidance, the planted row can be placed directly over the band, therefore obtaining a “starter effect.” These systems have worked well in reduced tillage, strip-tillage or intensive tillage systems.

This ends the series on the 4Rs of crop nutrient management. For more information on the 4Rs, visit the International Plant Nutrient Institute website at http://www.ipni.net.

Dr. Paul Tracy is director of agronomy for MFA Incorporated.

The 4 Rs of crop nutrition–the Right time

Written by Dr. Paul Tracy on .

Another installment in the 4 Rs of crop nutrition

Fertilizer timing is critical for economic returns on your farming. I’ll never forget a study conducted by Dr. Dale Blevins at the University of Missouri back in the late 1980s. Dale was able to obtain tremendous yield increases by delivering nutrients directly into soybean plants via medical intravenous setups. Obviously, using an IV to deliver nutrients is not practical, but it does demonstrate the value of a constant nutrient flow throughout the growing season.
Nitrogen receives the most application timing attention. This is because of its soil mobility. In almost all cropping situations, it is agronomically efficient to split nitrogen applications. In many situations, that translates into improved economic efficiencies.

Although many producers do quite well with all of their corn nitrogen applied preplant, I am a supporter of splitting corn nitrogen applications as a key management practice for producing consistently high yields.

Unless your environment allows for fall/winter anhydrous application, I usually recommend some nitrogen (a quarter to a third of the total crop needs) at or near planting, followed by the remaining nitrogen applied sidedress at the three- to six-leaf stage. This strategy provides the seedling adequate nitrogen. It also provides the growing crop with a dependable nitrogen supply immediately prior to the rapid growth that occurs between the six-leaf stage and tasseling. It also allows for mid-season rate adjustments based upon within-season environmental factors.

In wheat, I recommend two or three-way nitrogen splits. Some nitrogen (about a third) is needed at or near planting to stimulate fall tiller production.
The remaining nitrogen should be applied just prior to spring green-up. In planned high yielding programs (greater than 100 bushels per acre), the non-fall nitrogen can be split into two spring applications, with half near green-up and the other half near the boot stage.

Nitrogen use and timing for soybeans is often debated. Some preplant (10 to 20 pounds per acre), usually applied through nitrogen-containing phosphorus materials, can aid the seedling’s development prior to nodulation. Recent work has also shown that, under high yielding conditions (greater than 60 bushels per acre), 10 to 20 pounds of nitrogen per acre applied near pod set can help “finish off” a crop.

Tall fescue benefits from split nitrogen applications. In grazing situations, I prefer the majority of tall fescue’s nitrogen applied in late August to stimulate winter stockpile production. In hay situations, I prefer the majority of the nitrogen applied near spring green-up. In combination situations (hay + stockpile) a 60/40, spring/fall split application works well. When moisture conditions are appropriate, an additional nitrogen application in the early summer after haying or aggressive spring grazing pays great dividends.

Proper fertilizer timings do not only apply to mobile nutrients like nitrogen. Relatively non-mobile nutrients like phosphorus and potassium are commonly applied based upon convenience, and often applied once every other year. Although this timing philosophy works well in many situations, sometimes more frequent applications are beneficial.

High or low pH soils have the ability to fix or tie-up phosphorus. Some types of soil clays have the ability to fix potassium. In most cases, moving from a biennial to an annual fertilization system will help eliminate tie-up issues.
Certain crops (especially forages) have the ability to take up and remove via harvest more phosphorus and potassium than they require—a term referred to as luxury consumption. For this reason, in alfalfa, we generally recommend half of the annual fertilizer after the first cutting and the other half after the third cutting.

Environmental inconsistencies with the timing, release and availability of crop nutrients, along with higher commodity values have increased interest in slow-release materials, fertilizer enhancers, fertilizer protection products and bio-stimulants.
Some of these materials, like Super U, ESN, Agrotain, N-Serve and NFusion for nitrogen, and Avail for phosphorus, have been tested and can reduce the need for multiple applications in some situations. Other lesser-known and less researched materials may or may not help. Some have very little merit and should be avoided. Sorting through all the claims concerning untested products is a difficult task. My advice is to always stick with products that have been evaluated by unbiased, trusted parties.

Dr. Paul Tracy is director of agronomy for MFA Incorporated.

Crops - Use the right source

Written by Dr. Paul Tracy on .

Another installment in the 4 Rs of crop nutrition
 
When asked if urea is superior to ammonium nitrate, I usually respond with one of three words—yes, no or maybe. Last issue, I mentioned the 4 Rs of crop nutrition currently being promoted by the plant food industry. The Right source at the Right rate, Right time and Right place. Although the four are completely interconnected, let’s discuss the right source. I’ll use common nitrogen sources as a brief example. Other nutrients have similar but unique discussions of their own. All major nitrogen materials can be effective, if used in a wise and material-specific manner.

Anhydrous ammonia
Anhydrous ammonia contains the highest nitrogen analysis available (82 percent). It is consistently the lowest cost nitrogen fertilizer in our system. Anhydrous turns gaseous at atmospheric pressure and must be incorporated into the soil to avoid volatile losses. Application on rocky, cloddy, or excessively dry/wet soils may induce volatility. The obvious rule of thumb is that if you can see it or smell it, adjust your equipment or wait until better application conditions exist.

When applied properly, anhydrous is extremely efficient. It converts to plant-available ammonium rapidly upon contact with the soil. Its incorporation requirement advantageously places it in the root zone near crop roots. For a few weeks post application, anhydrous reduces soil bacterial populations responsible for nitrification. It therefore provides some “stabilization” properties which can lower potential nitrate losses.


Depending upon crop and weather conditions, anhydrous ammonia can be applied in the fall, spring or at sidedress during the growing season. The nitrification inhibitor N-Serve (Nitrapyrin) is a wise choice to delay fall and early spring applied anhydrous ammonia from nitrifying.

Urea
At 46 percent nitrogen, urea is the highest analysis dry nitrogen fertilizer available. This generally lowers its cost compared to other dry nitrogen fertilizers. Urea must be converted to ammonium before becoming available to plants. Some urea naysayers feel that a delay in ammonification makes urea an inferior fertilizer product. In reality, urease, the enzyme responsible
for converting urea to ammonium is one of the most common enzymes present throughout nature. Our soils and crop residues easily supply enough urease to rapidly convert urea to ammonium within a few days of application.

Urea’s biggest negative is that during the urease hydrolysis process, gaseous ammonia forms, making volatility losses possible. In cool weather (reduced urease activity) or when rainfall/irrigation moves urea below the soil surface, volatility becomes minimal. Under high urea volatility conditions (70+ degree temperatures, wet-drying soils and heavy surface residue), urea can be protected using the urease inhibitor Agrotain.

Ammonium nitrate
Unlike urea, ammonium nitrate contains nitrogen in the two forms that are immediately plant-available. It is also not subject to volatility losses. Since it is only 34 percent nitrogen, it is generally higher priced than urea. Under high rainfall/soil saturation conditions, the nitrate component of ammonium nitrate can be lost immediately via leaching or denitrification. I generally use this as a counter balance to the negatives associated with urea. Like most cropping decisions, the environment dictates which nitrogen material will perform best.

Urea ammonium nitrate (UAN)
UAN generally contains 28 or 32 percent nitrogen. It is a liquid material made from mixing urea, ammonium nitrate and water. Therefore, it possesses the strengths and weaknesses of both materials. Being a liquid, it fits weed-and-feed programs. Liquids also work well with knife delivery, especially during sidedress application. Some producers believe rate calibration and delivery accuracy are superior with liquid materials.

However, liquid materials do have a few negatives. You are transporting a lot of water, which often increases the cost per unit of nitrogen. In no-till or heavy surface residue situations, broadcast liquid
nitrogen materials can get captured and “tied-up” by residue before reaching the soil.

Ammonium sulfates/ ammonium phosphates
Ammonium sulfate, diammonium phosphate (DAP), mono ammonium phosphate (MAP), and the ammonium polyphosphates all provide plant-available nitrogen. Since they contain relatively low nitrogen contents (11 to 21 percent), their cost per pound of nitrogen can be limiting. Therefore, we recommend using them to meet crop phosphorus or sulfur needs. In most cases we credit the nitrogen in these materials toward the total crop need and supply the majority of the nitrogen through one of the higher analysis fertilizers.

When selecting a fertilizer material, consider their physical and chemical properties, combined with environmental
conditions present and the other 3 Rs. Visit your MFA Certified Crop Adviser to help evaluate which nitrogen material fits each field, each year, within your farming operation.

Paul Tracy is Director of Agronomy for MFA Incorporated.

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