Show Conservation Expert Explains b. b Need for Chemical Nutrients By Dy Dr Paul Christensen Utah State University Extension ki Sell Boll Conservationist Why do we apply fertilizers What chemical elements are needed by plants to grow and reproduce reproduce reproduce re re- produce Where do plants obtain these elements clements What fertilizer elements are aro needed In Utah soils If you can answer th these se questions questions ques ques- you have basic Information to help you make mako wise use of f fertilizers Why Fertilize We apply fertilizers to the soil to maintain a good supply of plant nutrients for the crop On Ona a time longtime best bis' i we mus must must- return re reo turn to the soli soil those elements removed removed removed re re- moved by the crop Some soils In their native state are deficient in certain plant nutrients These nutrients nutrients nu nu- must be supplied before satisfactory crop production can cane J be e achieved Essential Elements Of the 92 natural chemical elements 16 have been proved essential for plant growth and reproduction Three or four of these elements make up 95 per percent percent percent cent of the dry matter of the plants and fortunately these same elements come from air nir and wa ter The remaining 12 to 13 elements elements elements ele ele- ments come from the soil and make up only five per cent of the plants' plants dry matter All plants obtain carbon hydrogen hydro hydro- hydrogen gen and oxygen from air and water In addition some of the l legumes like Jike alfalfa clovers pens jeas I and beans obtain all or part of their nitrogen from the air 1 r Common fertilizer practice con con I In maintaining an adequate I supply of the el elements ments' ments taken from the soil The essential soil elements fire are nitrogen for most plants phosphorous potassium calcium magnesium magnesium mag mag- sulfur iron zinc manga nese copper boron chlorine e and molybdenum Lets Let's consider the situation on these elements in Utah soils I Major l Elements For field crops nitrogen and phosphorus are the major concern con cern in the state Our fertilizer practice then Is centered on these two and these alone Before con con con- the details on these two lets let's review the status of the theother theother theother other soil elements Potassium is needed in rela lively large amounts by crops I but numerous soil tests and field fertilizer tests throughout Utah how no need to apply apply- any ny for forthe forthe or orthe the present at least Potassium Is ceded In adequate amounts In our soils In addition some of our I irrigation waters contain i Blum lum I Calcium and magnesium make makeup makeup makeup up a major part of the lime Ume in ur soils Most of the agricultural mad Ind in Utah contains hund hundreds ds if it tons cf lime Ume per acre Our Irrigation irrigation tion waters carry calcium and magnesium These are the ele I ments merits that make our culinary water hard water For these I J reasons we will probably ney never never r re e iced d to add calcium or magnes turn lum to our soils in fertilizers The essential el element ment sulfur I has ha not been found diffident in Utah soils Sulfur is part of all sulfates It is in our salty soils soUs It Is carried In gypsum Fertilizers ers like Uke am sulfate and the super phosphates contain sulfur We also als get sulfur from smelter smoke It will probably bE bo a long longtime longtime longtime I time before sulfur Is deficient in Utah soils I I I I J Trace Elements The remaining seven soil elements ele ele- ments are known as minor or trace elements because they are needed in only very small amounts of crops Our principal concern with trace elements is to supply them I to plants that have difficulty in using the native supplies in the soil Iron Tons of iron are contained in inI each acre of land b but t some of our fruit trees and ornamental plants are not able to satisfy their needs for a few ounces Iron or yellowing of the leaves is a ammon ammon problem in peaches I r some ornamentals and other I i plants Several types of trent treatments can be used to correct this condl condi tion These Include spraying the leaves with iron compounds placing placIng placing I ing iron capsules in holes in tree trunks and applying iron to the soil coil Zinc deficiency occurs in a small percentage of at fruit trees In the state This can be corrected by applying zinc sulfate as a dor mant spray Zinc deficiency sometimes some times follows extensive application of phosphate in orchards A A. few Instances of manganese deficiency have been f found und in Utah however this is a rare oc Oc- currence Of he the e remaining trace elements elements elements ele ele- ments copper boron chlorine and molybdenum none have been found deficient in Utah soils Bolls Boron occurs at toxic levels in late summer in one or two streams in Utah Chlorine occurs in all nU our waters It is a major constituent nt in salty and alkali akaU soils In some of the western states molybdenum um Is excessive in some soe soils and causes cauSt's toxicity problems in cattle Returning to to nitrogen and use these statements to gude guide your fertilizer practices 1 1 Nitrogen is needed for grass the he grass crops small grains and corn and cash crops 2 Phosphorus is needed for alfalfa clovers and cash crops 3 For most mast effective use of fertilizers tie the fertilizer I rices tices to your crop rotation Apply phosphate to the crops with highest highest high high- est phosphate needs This will generally satisfy the phosphate re re- of all the crops In Inthe Inthe the he rotation Apply nitrogen ac 1 according ac- ac cording wording to the needs of f each crop The need for nitrogen Is greatly Influenced by your water supply For Par crops like Ute corn If you have plenty of water you should apply large lArie amounts of nitrogen |