This publication provides guidance on fertilizer rates at seeding time and fertilizing established stands for legumes, grasses, and grass-legume mixtures. Fertilizing irrigated forage is also discussed

Adams, Earl P.

Williamson, Edward J.

English

Public Research Access Institutional Repository and Information Exchange

South Dakota State University Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange SDSU Extension Fact Sheets SDSU Extension 1967 Fertilizing Pasture and Hayland Earl P. Adams Edward J. Williamson Follow this and additional works at: https://openprairie.sdstate.edu/extension_fact Recommended Citation Adams, Earl P. and Williamson, Edward J., "Fertilizing Pasture and Hayland" (1967). SDSU Extension Fact Sheets. 1411. https://openprairie.sdstate.edu/extension_fact/1411 This Fact Sheet is brought to you for free and open access by the SDSU Extension at Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in SDSU Extension Fact Sheets by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact michael.biondo@sdstate.edu. Historic, archived doculllent Do not assume content reflects current scientific knowledge, policies, or practices. SDSU ® Extension For current policies and practices, contact SDSU Extension Website: extension.sdstate.edu Phone: Email: 605-688-4 792 sdsu.extension@sdstate.edu SDSU Extension is an equal opportunity provider and employer in accordance with the nondiscrimination policies of South Dakota State University, the South Dakota Board of Regents and the United States Department of Agriculture. J FS 316 Fertilizing Pasture and Hayland Pho~phate fertilizer increa~ed net crop return by almost 40% on thi:-. lield of alfalfa t WITH FERTILIZER -- NO FERTILIZER Cooperative Extension Service South Dakota State University, Brookings United States Department of Agriculture Fertilizing Pasture and Hayland By Earl P. Adam5 and Edward J. Williamson, '-.__,. ExtensionA~ronomists-Soils Forages are essential to South Dakota agriculture because they provide much of the feed for livestock enterprizes. Nearly three~fourths of South Dakota's land is used for pasture and hay production. It is esti~ mated that less than 1%of this forage area is fertilized compared to krtilizer~use on 15% of the corn acreage. Frequently overlooked is the fact that 5 tons of quality alfalfa is equivalent in feed value to about 113 bushels of corn, 104 bushels of wheat, or 223 bushels of oats. Equivalent amounts of good grass forage com~ pare favorably to alfalfa in total digestible nutrients (T.D.N.). Proper fertilization is a key factor in producing high quality livestock feed. It also extends the pro-ductive life of fields seeded to some forages. Not all grasses can be fertilized profitably, how-ever. Here are some advantages you can expect from properly fertilized forage crops: • Increased forage yield. • Increased seed production of forage plants. • Earlier spring grazing. • Later fall grazing. • Increased nutritive feed value. • Increased efficiency of water-use by plants. Important increases in forage yields and protein content from fertilizer use have been demonstrated by research in South Dakota and neighboring states. For example, here's what 60 pounds of actual ni-trogen per acre did for crested wheatgrass in Lyman County: • Nearly doubled the hay yield (from 1,480 to 2,760 pounds per acre). • Protein content of harvested hay was boosted (8.4% protein for unfertilized, 10.7% for ferti-lized). Likewise research shows significant alfalfa yield increases from fertilizer use, particularly those con \._.; raining phosphate. Alfalfa in Grant County fertilized with 60 pounds per acre of actual phosphate (P:.:0;,) yielded about 1,800 pounds more forage per acre than that not fertilized. Such yield increases are more like-ly on soils testing low in available phosphate. Grasses differ from legumes in their nutrient needs. As a result, recommended fertilization prac-tices also differ. Both grasses and legumes require all of the essential plant food elements for most favor-able growth. Basically, however, grasses - particular-ly the cool season varieties - respond to nitrogen fertilization whereas legumes respond primarily to phosphorus and in some cases to potash fertilization. Soil testing is a reliable guide in determining the best rates of fertilizer to use. Fertilizing is not a substitute for adequate moisture and proper management, but plants use available water more effectively when high soil fertility exists. Research has not clearly proven any particular ad. vantage to spring or fall fertilizer application as far as its effect on yield or protein content. One advantage of f~ll fertilizer application is that of earlier spririg grazing. Fertilizing at Seeding Time Stand, seedling vigor and eventual yield can be im-proved by using fertilizer at seeding time. This prac-tice can mean the difference between a stand and es-sentially no stand where soil fertility levels are very low. The preferable application method is to apply starter fertilizer at seeding time with a fertilizer at• tachment on the grass seeding implement. Fertilizer may also be broadcast on or near the soil surface at seeding time; however, increased weed competition may decrease growth rate of newly seeded legumes and grasses. This is particularly true if the fertilizer contains a high percentage of nitrogen. Band place-ment of starter fertilizer about an inch directly be-low the seed gives more effective fertilizer use by new seedlings yet minimizes benefits to weeds. Oc-casional weed clipping may be necessary if serious competition restricts new seedling growth. Fertilizer rates at seeding time should be based mainly on the available plant nutrients in soil. Soil tests are effective ways to determine these existing soil fertility levels. Fertilizers containing nitrogen and phosphate in one-to-four ratios (i.e. 11-48-0, 8-32--0), are well suited for use as a starter. Table 1 shows fertilizer rates to bt' used at seeding time depending on soil test level. For example, a soil testing medium in phosphorus and t1er_Y low in potassium would require a fertilizer app!i -canon rate of 40 pounds of phosphate (P~O.-,) and 80 pounds of potash (K20) per acre for a new legume seeding, with the nitrogen application being one-fourth the rate of phosphate, or 10 pounds of nitrogen (N). Fertilizing Established Stands Phosphate and potash, but no nitrogen should be used when fertilizing established stands of legumes. Table I. Rccommcndcd Dryland Fertilizcr Rates. Very Low Low Medium High Establishing New Legume Seedings 60 26 80 66 60 26 60 50 40 18 ➔5 37 0 0 0 0 •RcJtanllc,,ot thc,ml 1c,1 for1>rJtani~ niancr (nitroj:cn a1a1IJbilit1·),J!l pl) fllW>JtCfl,1I 1.ththcphmphatcJppliGHion rate. The reason for not using nitrogen is that the nitro• gen supplying ability of legume seedlings is nil but mature legume plants can adequately provide nearly all of the plant's nitrogen needs. Seed innoculation at planting time helps provide mature legume plants with active bacteria which can supply the needed nitrogen from the air rather than from the soil.Phos• phate and potash fertilizer rates for established leg• ume stands should be based on soil test results as list• ed in table 2. Fertilization for Seed Production Proper fertilization can increase seed production. Fertilizer rates for established legume seed fields would be the same as those for forage production (table 2). Table 2. Recommended Oryland Fertilizer Rates. Established Legume Stands-Hay and Pasture* Very Low Low Medium High 60 26 80 66 60 26 60 50 40 18 45 37 0 0 0 0 GRASSES Fertilizing established grasses is different from fertili7,ing legumes because grasses do not obtain ni• trogen from the air. For this reason, nitrogen should be supplied from other sources, such as commercial fertilizer, to increase forage production. Phosphate and potassium, although necessary for best yields, are generally required by the plant in somewhat smaller amounts than nitrogen. Here again soil tests can help determine such needs. Fertilizing at Seeding Time Proper fertilizat ion also improves grass seed ling vigor and stands. Use of starter fert il izer is a recom• mended practice for new grass seed ings. It can be appl ied with an attachment on the seed ing equip• mentor by broadcasting. New grass and legume seed. lings init ially have about the same nutrient needs. Recommended fertilizer rates and application meth• ods for new grass seedings are the same as those for new seedings of legumes (see table 1). f ertilizing Established Stands Grasses arc classed as cool season or warm season, depending on what part of the growing season major growth takes plact'. Commonly grown cool season varieties include smooth bromegrass, intermediate whcatgrass, crested wheatgrass, western wheatgrass, Recd canarygrass, Russian wildrye, green needle-grass and bluegrass. Warm season grasses include switchgrass, Indiangrass, the bluestems, the grama grasses, buffalo grass and others. Nearly all cool sea-son grasses respond profitably to fertilizer while most warm season g rasses do not, with the except ion of switchgrass and sudangrass. Major growth by cool season grasses is in the early and late parts of the growing season whe11 moisture is less likely to be limiting and mineralization or release of soil nitro• gen is slower. These factors, plus differences in plants themselves, usually make nitrogen fertilization of cool season grasses profitable. S0<.l.bound conditions can occur in older pure grass stands where few or no legumes, manure or ni. trogen fertilizer have been used. Adequate nitrogen fertilizer use can prevent and correct such conditions. Tearing up old sod apparently gives no permanent correction of the problem. Fertilizer rates for cool season grasses range from J 40 to60 pounds per acre of actual nitrogen, depending on expected rainfall during the growing season. Good stands o( cool season grasses in the eastern quaner or South Dakota need 60 pounds of actual nitrogen per acre, applied in very late fall or early spring for best results. Normally little or no nitrogen will be lost from fall or spring applied fertilizer. Occasionally, however, losses occur on sloping land where fertilizer has been spread on frozen soil or snow and rains or thawing results in heavy surface.water runoff. The 40. to SO.pound rate per acre of nitrogen should be ap, plied in western counties where forage yields may be restricted by limited rainfall. Phosphate and potash may be used for established grass where soil tests in. dicatc low nutrient levels of these elements. Sec table 3. Many pastures contain mostly Kentucky blue. grass. It's yielding potential is lower than that of other cool.season g rasses . Thus, fertilizer app lication rates, consisting maifl ly cf nitrogen, should be reduced tn about 6()0/4 of those rates in table 3 recommended for other cool season g rasses grown in the same area. Genera ll y warm season grasses do not respond as much as cool season grasses to fe rtilizer in terms of total increased forage. H owever, there are two possi-ble exceptions - sw itchgrass and sudangrass. These two varieties respond to fertil izer nearly like cool seas-son grasses and, therefore, should be fertilized as such (seetable3). Table 3. Recommended Oryland Fertilizer Rates. Established Grass Stands-Forage Very Low Low Medium High 40to60 40to60 40to60 40to60 Seed Production 20 20 0 0 80 60 45 0 66 50 37 0 Fertilizer - especially nitrogen - helps increase grass seed production. Fertilizer should be applied at the rate of 40 pounds actual nitrogen per acre in lower rainfall areas of South Dakota and up to 60 pounds in higher rainfall areas during late September or early October of the year before seed harvest. Additional phosphorus, and in some cases potash, may also be needed for top seed production on fields suspected of having unusually low fertility. Phosphorus and pot-ash may be applied at the same time with nitrogen as a mixed fertilizer at rates shown in table 4, based on soil tests. Table 4. Recommended Dryland Fertilizer Rates. Very Low Low Medium High Grass Seed Production 40to60 40to60 40to60 40to60 30 30 0 0 13 13 0 0 GRASS-LEGUME MIXTURES 80 60 45 0 66 50 37 0 Fertilizing new grass-legume mixtures pure stands of either. or established stands of important as fertilizing fertilizing at Seeding Time The same fertilizer rates are recommended for new seedings of mixed stands as are used in pure legume or grass stand establishment. For the particu-lar type and amount of fertilizer see table l. fertilizing Established Stands Applying phospate and potash fertilizer to mixed Read these Fact Sheets for establishment, utilization stands frequently increases legume vigor and growth more than that of the grass. More legume growth, how<::ver, permits greater nitrogen fixation by the legume, thus assuring more available nitrogen for in-creased growth and vigor of the grass. This effect is more likely to occur where the forage stand consists of more than 35% legumes. Fertilizer application rates correspond to those in table 2 and vary from 40 to 60 pounds of phosphate (P,O,,) and 45 to 80 pounds of potash (K~O) depending on soil tests. Where mixed legume-grass stands contain pre-dominately grass vegetation, maximum forage yields will be obtained by applying fertilizer containing ni-trogen. Fertilizer rates under these conditions vary from 40 pounds in areas where limited rainfall may restrict yield, to 60 pounds in extreme eastern South Dakota as found in table 3. Eventual loss of the limit-ed number of legume plants in such a stand should be expected where straight nitrogen is used. If the legume plants are to be kept in the stand, some phos-pha~~ and potash should be applied with nitrogen fertilizer. FERTILIZING IRRIGATED FORAGE Irrigation can provide substantially greater forage yields - but a correspondingly greater amount of plant food is also required. The ratios of nutrient de-mands of irrigated plants differ little from those grown und~~ dryland conditions; however higher rates of fertilizer should be used. Phosphate and potash application rates for estab-lished irrigated forage should be increased 300/4 over those recommended for the same dryland concli-tions. For example, a recommendation for established dry land forage, calling for 0+60+ 30, should be in-creased to 0+80+40 if the same field is to be irri-gated. Nitrogen application rates for established irri-gated grass to be harvested for forage should be in-creased two to three times over those for similar dry-land conditions. For example, a recommendat ion for established dry land grass forage, calling for 60 pound,; of actual nitrogen per acre, should be increased to 150 pounds under irrigated conditions. This 150-pound rate should be a split application, half of it in early spring and the other half immediately after the first cuttmg. ~{~t;~g:WfSi~l~ luucd in fwrtberancr of C.oopu11ivc Ex1cn1ion work, Acu of May 8 111d J-.,nc JO, 191i, u:i coo~r•tion with the United Statc1 Dc-partmcu of A1 ricuh1m:. Joh• T. Stone, Dun of l:ll ttnaioa , Sou th D1 lr. 01:1. 511 1c Univcr1i ty, ~roolun11, FS 316 Fertilizing Pasture and Hayland Pho,phatc fcrtilizcr0;~1iei:fi~l~e1t:1rarf:1um b1· almost 40% .1,~~ ~~:i:t:~~: Cooperative Extension Service South Dakota State University, Brookings United States Department of Agriculture 

Fertilizing Pasture and Hayland

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Fertilizing Pasture and Hayland

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