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• .Jilt' Grouping
<br />Capability gt'ouping sho+vs, in n ~cral o~;+}~, the
<br />suitability' of soils ter most kind.; nl field crops. The
<br />g+'oups are merle accarrling to the IimiLitiuus of Lhe
<br />soils when used for field crops, the rich ni d:uuage
<br />+ahen the)' are used, and Lhe ++ay they respun~l to
<br />~reatment. 1'he groupings rlu nut L+kr. into account
<br />+a.jor and general!}- expensive lanrlfurming that +euuld
<br />change slope, depth. or other charrcterislics of the
<br />soils; rlo nut take into consirlcratinu possible, but un-
<br />likely, major reclamation prniects; ;uul do ant apply
<br />to rice, cranberries, horticultural crops. ur other crops
<br />requiring special management.
<br />Those familiar t~ith the capability classilic:+lion can
<br />infer from it much about the beha~iur of soils +rhen
<br />used for other purposes, but this classilicntiun is not
<br />a substitute for interpretations designed to shmc ~uit-
<br />al)IIIt1' and llmltatlan5 of groups of soik for rank,
<br />woodland, or engineering.
<br />In the capability system, all hinds nl soil arc ;,•rnuped
<br />at three levels, the capability class, the suluhus. and
<br />i the unit. These levels are delinerl in the follo+cing para-
<br />graphs.
<br />C)APA E+LITY CLASSES, the brnndesl groups. me rlasig-
<br />nated 6c Roman numerals 1 throu;[h \ II I. 1'ho uu-
<br />me+:als inrlicnte progressiveh' greater limitntiuus and
<br />narrmrer choices fur practical use. delined as I'olln++s~
<br />Class I soils haee fe+a limitations that restrict
<br />their use. (None in Rin Cranrle Gninty .area.)
<br />Class 11 soils hate ntodernle IimiG•diuns that re-
<br />duce the choice of plants nr that require m~d-
<br />erate consereatinn practices. (None iu P.io
<br />Gr;uule County Area.)
<br />Class III soils have severe limitations that reduce
<br />the choice of plants, require special amsercation
<br />practices, or both.
<br />Class IV soils ha+~c yer}~ se~~cre limilnlians that
<br />reduce the choice of pl:utts, require very careful
<br />management, ur both.
<br />Class \' soils are no[ likely to crurle Intl hnyc other
<br />limitations, impractical to renurcc, ih;tt limit
<br />their use I:u'gely Gr p;tsture, range, ++uorlland,
<br />ul
<br />Class \'1 soils have scture limitations 1h,it make
<br />them genernllc uusuilerl to culUyaGon :uul limit
<br />their use hugely to pasture ur ran;,~e, +cundhmd,
<br />or wildlife.
<br />Class V11 mils have eery severe limitations that
<br />male them unsuited to culliyation ;nxl that re-
<br />strict their use hugely to pasture or range,
<br />woodland, or +cilrllife.
<br />Class \%III soils nnrl laudl'orms hate limitations
<br />that preclude their use for cnnnuercial crop
<br />prrxluctinn and resGicL their use to recreation,
<br />+cildlil'e, or +rater supph, or to esthetic pur-
<br />poses.
<br />CAPACILITY SUL'CI„\SSEF :u'e soil groups +yilhin one
<br />class. 't'hey :ue designated by adding a small letter, e,
<br />a•, .~, or r, to the class numeral. for ex:unple, I l le. The
<br />letter r shmys that the main IimiLtliou is risk uC erosion;
<br />that water in ar on the soil interferes with {?lint
<br />growth ar culticaliou (in some soils the wetness eau
<br />be partly cmrecterl by' artilicial drainage); s shores
<br />that the soil is limited mainly because it is shallow',
<br />hroughty, or stony; and r, used in only soave louts of
<br />hp United States, shows that the chief limitation is
<br />climate that is [uo cnlrl ar too dry.
<br />In class I there are no subclasses. because the soils
<br />of this class haee few limitations, Class V can contain,
<br />at [he mist, only the subclasses wdicaterl by rc. s, and ~.
<br />because the soils in class V are subject b+ little ur no
<br />erosion. although they !rave other limitations that re-
<br />strict their use largely to pasture, range, woodland,
<br />u i)rllife, nr recreation.
<br />+cilrllife.
<br />Si~c~/
<br />CArncu.rrY Ur+~are soil groups a ilhin the sub-
<br />clas,<es. "fhe soils in one cnpahilitc iniit are enuufih
<br />alike to br. suited to Lhe same crops and pasture Nlnuts.
<br />to require similar management, nnrl Lu h;t~~e simil,n~
<br />prnrlucli~ ity :uul other res{noises G. nnnagemenl. Thus,
<br />the capalrilih' writ is a convenient }trouping for mnl:-
<br />ing mane stttemeuts about m:uuy;cment of sails. Capn-
<br />bilily twits are genernllc rlesignalcrl by nddin;t 'ut
<br />A+:abic numeral to the subclass a~mbnl. lug evunple.
<br />Ille ° or I\-e-l. 'I'Ims, in uuc symbol. lhr. Cuman nu-
<br />mernl designates the ralc+hilitc class. ~n degroe of
<br />limitation; the sm;dl letter indicates ll+e cubclns~. ar
<br />kind of InuiLitiun, as rlclMal in the fnrc;p~ing Irnra-
<br />graph; and the Arabic numeral sl'ecillc;illy identifies
<br />the cnpabililc unit ++ithin r_;tch sul~clas~.
<br />~llnnrr^rnuvrl by rnpn Lilih~ units
<br />9'he capabilit> units in the l;lo Gr;indc ('aunt> Ares
<br />arc rlesrriberl un the Rages that fnlhm, and use and
<br />nuuutgentent is su;.•gested fur the ,ails in each unit.
<br />Almost all the irrigated soils in the surce~ area are
<br />in capability class III m• l\~. liouper lo;uny sand, hu~c-
<br />eyer, is in class \'[. Because the cold climate :uul .ehnrl
<br />gron•ing sensun xre seyerc limit;tlinns to use of the
<br />soils for craps, no soils in the :1re^ are in class I ~n I I.
<br />In graupiug' the soils into irrigated c;ymbilily units. it
<br />is assumed that sullicienl ++-atcr is n+~ail;+blc lei irri-
<br />gation and that the soils are irrigalerl. Nnnirrig;+led
<br />soils are in chess V through \'ll I. 1'he> are nut suitabh•
<br />for culticaterl craps because of the dry climate ur other
<br />soil conditions. '
<br />To feud the names of all the soils in any given c;ipa-
<br />bility unit, refer to Lhe "Guide l0 Slapping Units" at
<br />the back of this surge}.
<br />c.rr.uni.n~' u~~rr ui~~-i
<br />This unit consists of deep, nuxlerntelc pernienble.
<br />.Fell drai ued or moderately ~ecll drai ucd {a;uns. Sln{ies
<br />are 1 to " perceut.'I'he aanilable cater calrncily is high.
<br />'these mils ;ne irrigated. The Il ost free season i; !711
<br />to 115 d;n's.
<br />Thee sails are suited b. irrigated crop.; :uul t.. tn~sl
<br />craps gro+.n in the Area. 'I'liec :u'e ;ds~~ suited to Icss
<br />intensive uses, such ns irrigated pasture. Snnmlh
<br />brume, orcharrlgrass, intermediate ~cf+eutgrasx, Rus-
<br />sian a•ilch'ye, swectclaver, and alfalfa (jig. I'S) arc
<br />some oC the most commonly gro+yn plnufs for irrigated
<br />pasture.
<br />"Che slope and the control of irrigation ~ynter ore
<br />the main conrerns of management. Irrigation ++;tlcr
<br />nuwagcmeuL, fertility maintenance, hunt Ic+~eling. ;cud
<br />crop rotation protect the soil ng;tin.d deterioration and
<br />help b. maintain prorluctiun. Purrm+s. contour furro++s,
<br />contour ditches, and sprinklers :u'e suitable (ur irriga-
<br />tion. The length of runs xhoulrl be shorC to control
<br />erosim+. Managing the irrigatiot water is easier in
<br />areas that can be leveler!. A cropping .<> stem that in-
<br />cludes close-grow ing crops ai«1 leguwe< ;uirl mth a
<br />limited number of ru+e crops helps to maintain filth
<br />and fertility.
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