The Nevada County picayune., 1916-04-13
SOILS AND SOIL FERTILITY
No. 5. Organic Matter.
By De Y. Hungertord, Assistant Az ronOms3t, University of Arkansas


 The organic matter Of the soil Is that par which has been derived from the decay Of plants When the leaves, blades of grass, stems and roots O. plants de they ase at once attached by molds and bacteria The dead yegation gradually decomposes or dis integrate5 until the original appear. ance and structure is lost and the material becomes a dark colored shapeless mass, called humus.
 Effect of Organic Matter on the Soil
 Organic matter is beneficial to both sandy and clay soils, but in different ways A clay soil without organic matter is too sticky and compact The organic matter Ioosens it. permitting the surplus water 10 drain away and allows air to penetrate to the roots of the crop On the other hand, sandy soils are too loose and open Water drains away too rapidly and too much air is permitted 10 enter.
 Effect of Organic Matter on Moisture. Sandy soils that are we'll supplied with organic matters are more reten- tive of moisture than if lacking in that substance. The large spaces between the sand permit the water to draw away 30 rapidly that 1t is soon lost and the soil dries out. If thsse spaces are filled with organic matter the water meets more opposition in its dovnwsrd movement consequently 1t remains for longer time in the zone occupied by the plant roots, The fact that organic matter is exceedingly porous adds to its water holding power. This is shown clearly by CT perimsRts showing that 100 pounds of straw will take up 200 pounds of wa ter whereas the same amount of sand will hold only twenty-five pounds, and 100 pounds of peat soil. which con sists entirely of humus, will take up from 500 to 1 900 pounds of water
 Clay soils do not need to have their water holding capacity increased be cause they are naturally very renten- tive of moisture, such soils are SO compact. however, that the roots have difficulty in penetrating deeply into the subsoil Consequently the crops are likely to be shallow rooted. The surface soil dries out quickly and the crop suffers. This accounts for the fact that crops often suffer from drought on clay lands sooner than on more sandy soils If organic matter i. supplied to clay soils Inc crop will root deeper as a result of the more open structure and therefore UiIl be able 10 utilize the moisture stored in the sut soil and can resist drought
 Organic Matter and Plant Food.
 Organic matter not only improves the physical condition of soils and aids moisture control, but if also con. tains a large amount Of nitrogen and other plan feeds in an available form When the organic matter decays this plant food can be used by the sue ceeding crops.
 Soils That Need Organic Matter
 The soils of the South are. as a rule. deficient in organic matter be- cause the high temperature of the summer seasons causes decomposition 70 take place very rapidly. This ten dency is enumerated to q certain ex tent on the creek and river bottom soils by the fact that the large amount of vegetation produced has caused a large supply of organic mat. ter to be stored up. Continuous crop ping 70 corn and cotton however soon exhausts this original supply go that even the rich bottom soils be, -ome depleted after twenty-five or thirty years. The presence of an abundance of organic matter is shown by a black or dark brown color extending several inches below the surface A lack of organic matter Is shown by a light gray or red color
 Methods Of Increasing Organic Mat,
 ter Content of the Soil.
 The amount of organic matter fin the sol can be increased by applying oaruyard manure by turning under al rbe corn and cotton stubbs. s.ubble from sran sod of meadows and bv turning under green crops The sub ect of mauures WiI be treated H another lesson The practice ct U.n. ing under green crops called aarse. maturing Whore t.N live stock ara kept tI.s ls au excellent we4r- Q adom1 or-aH.c matter to ll. soil Iae crops Hse3 fe" this pua. include coHpla-. soy beans. clover. rye oa,- ari wheat The frat tbga mentioned Q. peas, beans ... clover are ,egumes and are cspaH of taking nitrogen from the air and putting il into the soil They do this with the talp of bacteria living on their roots