Exactrix Western Guidelines for Alfalfa Fertilization in Rotation...
Exactrix Times, Issue 146, Nov. 30, 2013
Western Guidelines For Alfalfa Fertilization.
Nitrogen is a major component of alfalfa. Alfalfa requires large amounts to produce high-protein hay. Yet for most producers nitrogen is not a major concern. This is because alfalfa is a legume and has the ability to live in a symbiotic relationship with nodule forming bacteria. These bacteria, which live on the roots, provide the alfalfa plant with an abundance of nitrogen.
Root development of alfalfa can be as deep as 12 feet in the second year. Root depths of 15 feet have been reported in California where Alfalfa grows year around with up to 12 cuttings.
Alfalfa is very sensitive to compaction. Heavy machinery should be avoided when the soil is plastic or compactable with axle loads over 2.5 ton. Avoid animal grazing.
The main concerns about nitrogen for alfalfa are centered on these nodules. First, the bacteria must be present. They usually are in older fields but may be lacking in newly-developed soils. To prevent problems, add the bacteria to the seed, either by directly inoculating the seed with an in-planter box treatment or using seed that has been coated with a coating that includes the proper inoculant.
The cost of seed inoculation is a very minor cost to prevent problems. Secondly, create or maintain a favorable environment for the nodule bacteria.
This begins with seed storage, store the seed in a cool place, out of direct sunlight and high temperatures. Remember that the bacteria has an expiration date, after which it will be less effective. In the field, the bacteria are sensitive to soil pH.
Acid soils, below pH 6.5, can limit survival of the bacteria.
In the Western states, the soil pH is usually not a problem, but is a serious problem in the Midwest and East.
Acid soils can occur where rainfall is significant or low salt irrigation water is used. It can also develop where ammonium fertilizers are used, especially on sandy soils.
There are soil acidity problems in some parts of California. Liming soil is the correction for a pH that is too low or too acid.
If the root zone of the alfalfa plants is restricted to the upper part of the soil profile, the nodules may be limited enough so that they cannot meet the nitrogen demands of the plants.
Supplemental nitrogen might be helpful under those conditions, but it would be better to correct the problem causing the restricted root growth.
Some growers apply small amounts of nitrogen at planting time, in the belief that this helps the plants get started. Normally, this does not help and, in fact, can slow down the establishment of effective nodulation.
The alfalfa plants will use available nitrogen in the soil first, then turn to the nodules to make up any shortfall.
Alfalfa Rhizobia (R. meliloti)
Seven Rules of Inoculation of Alfalfa Seed and Soil.
1. Purchase fresh inoculants from the proper cross-inoculation group. Before completing purchase, note the expiration date printed on the container and make sure that the bacteria culture is of a strain that will inoculate the legume to be planted. See Table 1 for legumes included in each cross-inoculation group. Store culture in a cool, dry place until it is to be used.
2. Inoculate if there is any doubt as to whether bacteria of the proper strain are present in the soil. If peanuts or soybeans have a long history of being planted in the field, less response to inoculants may occur.
3. For powder inoculants, follow directions for each crop. Put a sticking compound on the seed, then add inoculants and mix well with seed. If seed becomes too wet, allow to dry before putting into a seed hopper for planting. Do not allow direct sunlight to hit the inoculated seed. During planting apply granular inoculants in the seed furrow at the manufacturers recommended rates.
4. Do not allow seed to contact caustic lime or soluble fertilizers. Some seed-protecting chemicals are incompatible with legume bacteria. Molybdenum may aid in nodule formation on soybeans planted on mineral soils that have not been limed to the optimum pH. Do not purchase inoculants pre-mixed with molybdenum because the bacteria may die in such pre-mixes. If needed, these materials should not be mixed with the inoculants until just prior to planting.
5. Plant inoculated seeds at once (within four hours) and cover them immediately. Pack the soil with suitable equipment, such as a corrugated roller for broadcast plantings, or a planter press-wheel for row plantings.
6. Plant when soil temperature and moisture are favorable for quick germination of the legume and favorable for the survival of the bacteria.
7. Inoculants can also be applied to the soil. Inoculants can be applied as a liquid with high uniformity in the soil. Liquid application reduces Rhizobia cost and is more crop effective.
Alfalfa In Rotation With Corn, Timothy, and Seed Potatoes. Western Irrigated Production along the Spokane River.
Chloride based fertilizers must be avoided when potatoes are grown in this western rotation. Therefore potassium is supplied with sulfate and sulfur.
Liming is required to improve pH so bacteria can thrive resulting in raise good crops like Alfalfa Sandy soils drop in pH rapidly as compared to heavy clay loam soils.
This also means that if alfalfa is grown in a soil high in nitrogen, it will use it first. This feature of scavenging mobile nutrients is a promoted and understood role for alfalfa .
Alfalfa is a plant tailored to clean up nitrogen-polluted soils.
Alfalfa may be one of the best plants to remove nitrates from effluent water. The soil nitrogen status in an alfalfa field may test very low.
Thus Alfalfa is used to clean up soils and bring the soil life back following potatoes. Potatoes are a very difficult crop to raise when the environment must be considered. Timothy is also a very good perennial for improving soil life.
This can be an advantage, in that weed growth is discouraged by the low nitrogen levels. Also note that use of nitrogen only occurs during the growing season, if water is applied during the dormant season, little if any of the nitrogen will be used by the plants.
And finally, when alfalfa is plowed under it releases the nitrogen in the plant back to the soil.
Plowing alfalfa is an old practice that is not good for the environment and the producers pocket book.
Banding Nutrients into desiccated alfalfa at 12 mph will allow the following crop to thrive.
Leaving the roots in place as water conducting channels and sources of organic N,P,K and S in decaying root channels is good economics with high water cost.
Rotating out of alfalfa is much easier with No-tillage banding of nutrients for the following crop such as winter wheat or spring wheat.
Plowing of alfalfa sod is not required with high speed, single disc, Mustang banding of P and K. No nitrogen is required following a good uniform crop of Alfalfa
Plowing of alfalfa sod is not a good way to improve water infiltration under a center pivot. Leaving the soil root pattern in place allows absolute highest levels of yield potential for corn or wheat.
A crop that can use this nitrogen should follow alfalfa in a rotation.
Phosphorus is the most important nutrient for growers to be concerned about because it is the one which is most likely to be deficient.
Soils vary in their ability to supply phosphorus.
Deficiency of phosphorus is hard to detect visually, unless it is very severe.
Soil testing for phosphorus is reasonably accurate.
The Olsen method is the preferred method in most western states.
This Olsen method uses sodium bicarbonate as the extractant.
This method is good for neutral to high pH and high calcium soils, poor for organic soils.
High free lime content in the soil can interfere with accurate interpretation of results
Water extraction is an alternate method for unusual soils. Other states and countries, may use different extractants.
The phosphorus content of the extract is measured and expressed in parts per million.
Guidelines have been developed for interpretation:
Phosphorus soil test guidelines: NaHCOJ methodCalifornia
0 to 6 PPM = low
6 to 10 PPM = marginal
10 PPM + = adequate
Other states ( Colorado,Utah,Idaho)
0 to 3 PPM = very deficient
4 to 7 PPM = deficient
8 to 10 PPM = marginal
11 to 15 PPM = adequate
15 PPM+ = high
Phosphorus Application Guidelines
Test Value Pounds of P205 per ton of Hay*
Very Deficient 20 -25 Ibs.
Deficient 15 -20 Ibs.
Marginal 10 -15Ibs.
Adequate 5 -10 Ibs.
High 0- 5 Ibs.
* Tons of dry alralfa hay ( projected yield
These guides are intended for general interpretation.
Individual soils may differ from these values.
These guides are for soil that is very deficient, it is probably better to make a substantial application of fertilizer to correct the deficiency.
Once an adequate level is achieved it can usually be maintained by replacing crop usage. Yield is an important factor in this calculation.
An average number for phosphate use is about 12 pounds P2O5 per ton of hay, the reported range is 10 to 14 Ibs. P205 per ton.
Unfortunately, not all of the applied fertilizer phosphorus is available to the crop. Some is "fixed" by the soil, changed chemically to a non-useable form. The amount that is fixed varies with soils.
Several fertilizer products can be used to supply phosphorus to alfalfa:
0-45-0 ( treble superphosphate) -a dry , granular product that is 45% P2O5. This material is non-burning, easy to spread, applied by broadcast or band application
and contains no nitrogen. It is becoming harder to get and may be phased out in the future because it is more difficult to make, and less profitable, than other phosphorus fertilizer.
11-52-0 (ammonium phosphate) -a dry, granular product that contains 52% P205. This material is the most popular source of dry phosphorus. It contains 11% nitrogen along with the phosphorus. It is applied broadcast or banded.
10-34-0 (ammonium polyphosphate) -a liquid source, containing 10% nitrogen and 34% P205. This product is widely used and available. It is broadcast, dribbled, water-run, banded and applied with weed control materials. This product is sold by weight, a gallon weighs approximately 11.4 pounds. It is also used to make mixed liquid fertilizers of other concentrations.
0-52-0 (phosphoric acid) -a liquid source, containing 52% P205. This material is used to make mixed liquids and directly applied by broadcast, dribble, banding and water-run. It is also used as a carrier for weed control materials, although compatibility needs to be carefully checked. It is an acid, so precautions must be taken in its use, storage and handling.
Available Phosphate (P2O5)...52.00%
When liquid materials are water-run, several factors must be considered to make it most successful. When applied through sprinkler systems, precipitation may occur in the system. This can result in plugging small sprinkler nozzles and coating the inside of the pipe. This can change the hydraulic properties and harm efficiency of the system. These problems do not occur with flood or border systems.
The application uniformity will only be as good as the water distribution is.
Water-run applications can permit frequent light applications of phosphorus, which is helpful in dealing with soils which have strong fixation tendencies and where extra applications are needed to make it through the hay season.
Manures are also good sources of phosphorus. They provide phosphorus in organic forms. They tend to provide phosphorus for a longer period.
Waste water from animal facilities and water treatment plants can also be a good source of phosphorus. These sources should be considered in planning a phosphorus fertilization program.
Manures are best used in alfalfa as a pre-plant, plowed-in application in a preceding crop. It is best to grow a cereal or grass crop which can use the nitrogen in the manure, and is not as sensitive to free ammonia as alfalfa.
Surface-applied manures are used in alfalfa production, but can make weed control very difficult to accomplish. Phosphorus in the soil is virtually immobile. It stays where it is put. It can be a pollutant if it is washed away by erosion.
Mustang tool bars band to 7.5 inch depths with 26 inch diameter
openers in all soil types under moist soil, growing root patterns.
Exactrix application is at 1% CV or Coefficient of Variation . This means only 1% of the liquid PKS fertilizer is not crop effective in the applied root zone.
http://www.youtube.com/watch?v=QuCAeCfBUnQ&fmt=37 Banding with mustang openers, a good video.
It is better to plow, disc or inject phosphorus into the soil when making pre-plant applications.
Banding, placing the material in concentrated strips, is the most efficient method of all.
Banding is preferred where soil is very deficient. If it is only a minor deficiency, the cost of banding may not be justified.
Banding without soil disturbance is critical to raising high quality alfalfa.
Banding phosphorus into established alfalfa is not needed, top-dressing works but it takes a lot more fertilizer and the response is slower.
Large dry fertilizer applicators have application CVs of 25% to 50% which result in fertilizer that is not crop effective and preventing the promise of high yields.
Shallow rooted Bluegrass is very sensitive to a poor application of nitrogen.
Rolling slopes complicate the application with changing ground speeds and sinusoidal delivery with air boom applications.
Phosphate, Potassium and Sulfur with Micro Nutrients perform best when the nutrients are banded into the soil at 1% CV of application.
Uniformly Exactrix deep banded (7.5 inch depth) nutrients provide the best geometric root access for good yields a maximum nutrient uptake.
Banding nutrients uniformly is also much better for the wildlife and humans. Fish will thrive in clean water. Our society and mankind requires clean water.
Clean water is critical for society to grow and prosper. Misapplication of nutrients is directly responsible for the loss of habitat in the Gulf of Mexico.
Poor quality water resulted in 20,000 graves on the Oregon Trail. The Oregon Trail has ten graves for every mile. That means about 5% of the pioneers died on the way west.
Most of the graves are children that drank poor quality water while parents boiled the water and drank coffee and hard cider.
Alcohol was critical to early pioneers since the water source could not be trusted. Nor could some of alcoholic brews which had methanol in the blend and drove the pioneers blind.
Societies blossom with high quality water.
When highly mobile nitrogen is applied to Bluegrass the uniformity of the application is critical. The same can be said for all phosphate and potassium fertilizer.
Micro-nutrients must be applied at absolute highest level of uniformity to get good response to Zinc, Cooper, Moly and Boron In fact non-uniform nutrient application is toxic to the growing crop and the future crops.
Yields and economics reach paramount levels of improved net margin with the Uniformity of Application at 1% CV. Exactrix dual staging manifolds allow low and high ground speeds at 1% CV.
Deep rooted Winter Wheat at 6 to 9 feet is very sensitive to surface applied nutrients applied with a spin spreader.
Variable Rate Application is not economically possiblewhen compared to banding. Windy days really complicate the application. Dry fertilizer applicators are very sensitive to changes in ground speed.
Misapplication often occurs with no knowledge to the producer. Gravity and speed are the enemy of dry application.
Non Uniform application of dry fertilizer is no longer crop effective, economically speaking.
About twice the dry fertilizer material needs to applied with non uniformity of spin spreader application.
Micro nutrients are difficult to apply accurately with dry fertilizer.
Site specific variable rate application with high CV application of dry fertilizer limits the nutrient performance.
The dry fertilizer application is fastwith high flotation dry fertilizer applicators.
The non uniform application of dry fertilizer normally requires an attitude adjustment visit from the agronomist selling the dry fertilizer material.
Variable flow of dry fertilizer creates Sinusoidal Flow from the spreader. The dry spreader creates uniformity problems and poor site specific VRT capability.
Do not over apply Phosphorus as applied P excess can occur, usually the problem is reduced availability of other nutrients, especially zinc or copper.
Variable Rate Application, Site Specific is best practiced with liquids and banding. Top dressing P fertilizer is not economic responsive requiring over application tdue non-uniform application and poor root pattern geometry.
Banding of P, K and S in a common band provides immediate spring response at a depth of 5 to 7 inches.
Metals such as Zinc and Cooper can also be injected into bands.
Yield enhancing Rhizobia can also be injected in the band with approved chemistry.
Depth of PKS bands and band centers vary. The spacing of 10 inch band centers at shallow depths of 3 to 4 inches is required. Quite often 15 inch band centers are just as effective at 5 to 7 inch depths as 10 and 12 inch centers. Initial banding at 10 inch centers is recommended banding a 15 inch centers is recommended after two or more years of early spring banding.
Late fall banding in dormant conditions may not be as deep due to dry conditions. Banding after freezing nights is highly recommended to improve the work load. Fall banding also has less chance of compaction.
Additional alfalfa seed can also be placed when banding to renovate eroded knolls and improve the stand.
Top Dressed application of P requires up to 60 to 90 days to get a response from surface broadcast phosphorus, so apply P early in the season.
Alfalfa quality is impaired by a deficiency of phosphorus, but excess phosphorus will not improve it more.
The sources mentioned are not equal in terms of plant response when uniformity and geometry is considered. Economics is an important factor in making fertilizer decisions.
Liquids require more special equipment, but can be combined with other operations to save costs. Most liquids are known to be superior in economic performance.
Liquids are easier to spread uniformly, but dry materials can also be used successfully if applicators are properly maintained and set up correctly and applications are not made on slopes or windy days.
Good international markets exist for Alfalfa. Transportation has been a critical part of the puzzle. High pressure cubers improve the bulk density for shipping overseas to international customers.
High quality alfalfa is an art, how to buy high quality alfalfa lies in a few trusted appraisers and market makers. About 23 million acres are in production making it the 4th largest crop by acres.
Alfalfa is third in value behind corn and soybeans and well ahead of wheat. Most growers in the western US are adjusting to the export market by cubing the Alfalfa.
Potassium Application Guidelines
Potassium is the second most common deficiency in alfalfa in California.
Many parts of California and most of Nevada have soils which can supply the needs of alfalfa without supplemental potassium fertilization.
Potassium deficiency can cause distinct symptoms in the foliage. Even when symptoms appear, economic response may not occur from potassium fertilizers.
Soil testing for potassium is fairly good, but with a catch. The standard extractant, Ammonium Acetate, may not accurately reflect available potassium status of some soils.
A second method, acid extraction, should be used where potassium deficiency is suspected. If the Ammonium acetate method shows adequate levels, no further test is needed.
Plant tissue testing is again the best way to assess potassium status in the plants. Potassium deficiency is a common problem in other parts of the United States.
Lack of potassium is associated with poor disease resistance, loss of stands and poor quality.
Potassium soil test guidelines ( Ammonium Acetate)
Potassium Application Guidelines
If potassium deficiency is detected and confirmed, supplemental fertilization can correct the problem.
Several issues need to be addressed first. If adequate potassium already exists in the soil, the alfalfa will still pick up added potassium. This is termed "Luxury consumption", taking the available potassium without increasing yield. There has been speculation that extra potassium will improve forage quality, however as we
learned last year, extra potassium in the hay may be harmful to dairy cows.
There is a balance that should be maintained between deficiency and excess. Tissue testing should be used to guide decision making on this topic. If fertilization is called for, excessive rates should be avoided.
Sources of potassium include:
Potassium Thio-Sulfate, KTS, Potassium Chloride or KCL, Potassium Sulfate, Potassium Nitrate, Sulfate of Potash Magnesia, and manures. Water can also be a significant source of potassium in some areas.
Potassium Thio-Sulphate, KTS can also be used, this is a good , time proven liquid source in cold weather application. Potassium movement in the soil is slight. It should be plowed down in pre-plant applications or banded. Established alfalfa can be top-dressed successfully. Banding is most often most effective requiring much less tonnage.
KTS is chloride free which allows rotation to other crops known to be sensitive to too much chloride.
The KTS numbers are impressive with 42 pounds of total nutrient per 100 pounds.
KTS is 0-0-25-17S and ideal to fertilize alfalfa and weighs 12.2 pounds per gallon.
KTS works well in cold weather down to 5 degrees F and can act as a carrier for micronutrients and Hydra Hume, Fulvic Acids.
KTS has 3.0 pounds of K and 2.1 pounds of Sulfur per gallon. The sulfur is 50% sulfate form.
Sulfur is an important nutrient for alfalfa.
Deficiencies do occur in parts of California, usually where there is substantial rainfall or very low-salt irrigation water is used. These areas are mostly in the northern portion of California. Most areas irrigated with ground water or Colorado river water will get adequate sulfur from those sources.
Soil testing is a poor method to determine sulfur status.
Where this deficiency is a historical problem, it is wise to apply elemental sulfur when planting new fields. Several years worth can be applied and plowed in.
Deficiencies in existing fields may require a faster acting source of sulfur, to supply sulfate quickly. Elemental sulfur is the most economical source but must be converted to sulfate to be effective. Gypsum, ( calcium sulfate), supplies sulfur in the sulfate form, but has low solubility.
When looking at water samples, remember that 2.7 times the PPM of a nutrient will give you the pounds per acre foot in the water in question.
Sulfur can also change the soil pH, avoid acidifying below 6.5. Excess sulfur can cause problems with Selenium availability also.
A recent problem in cattle production and horses. Selenium Deficiency in Western Cattle Herds. White Muscle Disease.
Selenium deficiency is an animal nutrition problem important in many parts of California and Nevada. Selenium can be applied in liquid forms and banded.
Liquid Streaming Flows at high pressure (350 psi) allow micro nutrients to work much more effectively.
Micronutrients are those nutrients that are essential but needed in only small amounts. They include: Zinc, Manganese, Boron, Copper, Iron, Chlorine, Molybdenum for plants. Animals have micronutrients needs. They include these along with Cobalt, Selenium and others.
Boron is deficient in a few places in California. It is important in seed production, less so in hay production. Excess Boron is a problem in several areas of California and Nevada. Excess boron causes leafburn and reduces yield.
Soil testing is not very accurate for Boron status, as a nutrient. Use plant tissue for this nutrient. Water should also be sampled when looking at Boron status. If using Boron fertilizers, be very cautious. Too much Boron, and you have a herbicide. Thus uniformity of application is critical. Miniscule amounts should be used when banding less...1 pound per acre since the Boron nutrient is so crop available when banded.
Molybdenum is also deficient in a few places. Plant tissue again is the best way to determine if this is a problem. Molybdenum excess is a problem in parts of California and Nevada. This is a serious problem because it makes the hay toxic to animals. If Molybdenum fertilization is needed, use caution and be accurate in application. Moly aids the Rhizobium Meliloti bacteria in fixing nitrogen. The right amount of Moly is critical to help the Rhizobium Melioti. Moly can be applied to the seed just before seeding. Moly can also be considered for liquid injection on to the seed at time seeding along with Rhizobia.
Iron deficiency is sometimes seen in alfalfa. It usually is because of high pH, limey soils, cold soils or saturated soil conditions. Most soils contain adequate iron, but it is not available under those conditions. Alfalfa is more tolerant to this problem than many other plants. Reducing the soil pH level can be helpful, but on soils high in lime, this is not economically feasible. "Strip Acidification" may be helpful in those situations. Strip Acidification is the application of acid materials in bands or surface strips, to lower pH in a localized area. The intent is to make a zone where iron is available to the plant. Water amendments are also used to lower pH.
Zinc deficiency is a big problem in many crops in California and Nevada. Alfalfa isn't one of them. Soils which test extremely low for zinc can produce high yields. There are some reports of deficiencies but this is very rare. The content of other micronutrients may be important to the animals which are eating the alfalfa.
Fulvic and Humic Acid can be considered in Alfalfa production.
High Quality seed potatoes are produced in 5 year rotations with Alfalfa, Timothy, Canola, Seed Canola Hybridization, Barley, Winter Canola, Winter Wheat, Spring Wheat, Garbanzo Bean, Commercial Corn, and Sweet Corn.
A Ponderosa pine forest protects this flood plain of the Columbia River Basin and the Spokane River. A mountain valley isolation of about 60 miles from the main Columbia Basin potato production area helps to keep the seed potatoes disease free.
“Clean Water results when nutrients are banded with Uniformity of the Application and the nutrients are specifically targeted to stimulate the potential of the crop.
Economics always prevail and banding adds up to $150 more net income per acre.”
Guy Swanson, with the help of many others.
For More Information:
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