The Springdale news., 1915-12-03
lI.-AoW PLANTS FEED


 Cooperative Extension for Arkansas
 Plants require Tor tl.eir growth, me chanieal support, air heat light wa ter and food. All these. with the exception of light, are supplied wholly or in part by the soil Composed as it IS Of rock fragments and deeayine vegetable matter, the soil offers place for root development and af lords physical support for the plant. The air present in the spaces be- tween the soil particles is used by the roots of plants. Heat is supplied in part by=the soil aS a result Of is physical condition Water. while not a component part Of soil is furnished to the plant by il. and the physical condition Of the soil determines the amount of water that may be reserved for use by plants. The water sur rounding the soil particles dissolyes plant food and the solution is absorb ed by the plant roots Thus The soil must not only furnish a physical sup port for plants, but it must supply plant food and afford means for transferring the lood 10 the plant.
 Ten elements of plant food are con sidered 10 be absolutely essential for he growth of plants Three of these carbon. oxygen and hydrogen. are ob tained from the air. while phospho- rus, potassium. calcium Qime1, mag nesium. iron and sulphur are obtained directly from the soil itsell
 Carbon and oxygen are obtained from the air, where carbon is pres ent in the form Of earbon-dioxide gas dition These gases are taken into the plant through the leaves. and there combine with water to form the complex vegetable compounds
 The nitrogen used by plants is secured through the soil Through decay Of the vegetable matter in the soil the ntrogen-bearing compounds in Il are broken down into more sim pie forms. which. through the acton of various soil bacteria. are soon { bS plants Win these processes go- ing on all the time (except when the soil is frozen or waterlogged) a con stant supply of available nitrogen IS provided The content of vegeta ble matter In the soil must be kept up at all times to insure sufficient quantity of nitrogen Tor good crops
 Nitrogen from The air can onlr be secured by growing Ieguminous crops on the roots ot which nodules are formed The bacteria living in the eodales gather nitrogen from the air n the soil. and store il in organic combination in The nodules. Some of this is used by the host plant. but most of Il Is left in soil to become available through decay of nodules.
 The mineral elements essential for plant growth are supplied by the soil They are part. to Il greater CT less degree. of the rock fragments which constitute the body of the soil
 Lime in soils becomes soluble so readily and our rainfall is so heavy. that Il has been washed from even the best limestone soils in Arkansas. Most of our soils, therefore, are lacking in lime sufficient for the sal isfac1ory growth of many lime loving crops. This, with other changes in the soil. has led to soil aCidity
 Phosphorus and potash are present in all soils. usually in quite insouble 1 form. They form a part of certain i minerals found in the rock fragments Of the soil These minerals are brok. l en down and the phosphorus and pot l ash made soluble through exposure to weather the atmosphere the decay of vegetable matter and | sliaht solt cnt effect of planf roots Potash in many of onr soils k present i'll sui ie.,nt quantities fo lasf for hundreds of wears hut because ot improper iii lage and an insufficient amount of de. cay Sins Negetahl. matter II does nol in all cases become soluble tasl enough to support good crops
 Phosphorus is he mineral element most seriously laekine in Arkansas soils For satisfactory crops of any kind | is necessary to reRlentish the 1 phosphorus supply by the application oI a phosphorus bearing fertilizer. raw rock phosphate. acid phosphate, or bone meal
 When the supply of any one of the len clements of plant food is limited. he crop - limited Since all of these arc furnished either by inc air or by the soil we know where 10 book for the cause Of an unSatisfactory crop As pointed out in the above paragraphs. nitrogen. phosphorus and potash are the essential clement tr which nanht atrrnt san ,lnSt h.. .-...--L-