105 lNfLUENCE Of LANDSCAPE ON THE PHYSlCAL ANO ...digital.csic.es/bitstream/10261/144009/1/Influence_landscape...lnfluence of landscape on the physlcal ano morphological propertles

lNfLUENCE Of LANDSCAPE ON THE PHYSlCAL ANO MORPHOLOGICAL PROPERTlES OY SOlLS fROM ALJARAfE (SW. SPAlN}

F. MORENO, J.L . MUDARRA and A. VIRAS

Centro de Edafología y oiología Aplicada del Cuarto (C.S.l.C.}. P.O. oox 1052; 41080 Sevilla (Spain}

lNTRODUCTION

105

ihe pr~sent work la a part ef a ¡anoral study on the Aljarafe zono. area within tho provinco of Sevilla (SW. Spain) aituated on 8 Tortiary ~te8U. be! woon tho rivera Guadalquivir and Guadiamar, 100 to 150 m high (Fig. 1) .

This zono, togothor with thoso of Condado de Huelva and Algarvo in Portu­gal (Conferenco on Moditerranean Soi18, 1966) show the formation of red soila developed on Tortiary sandstonos from SW. of Iberian penir.sula.

Modolling of landscapo by araaion and phonomena medo interven~ oIdor mate­ríaIs, as Tortonian marIa and nowor .ateríaIs as aandy Plioceno and Quaternary eIomonts into the actual land configuration.

Envirc.nmontal condi tions can be considerod 8S typical lar Medi terranean el! mate. Aecarding to Thornthwaite is .esotheraal subhuaid or dry-s~d and to the Soil Taxonomy the moisture regime ia xeric and that of temperature thermic.

Referring to original vegetation it fa difficult to find some remain from it due to deforestation, very sovero aince very old timos. However, the origi nal forest ahould be for.ed by Querqu5 illex, Querqus suber, Olea europea, Ce­ratania ailliqua. Actual dedication i8 mainly olive trees and o vmryards exis­tine: in this area tor many years now. Cereala can abo be found in certE.in pI,! ce8.

Resulta whieh follow intend to ,ive an idea of the general 80il charBcteria tícs as wo11 al ot the physical charactrristie8 of a 60il srquenee within a ro proscntative pilot zone (88 in Fig. 1).

RESULTS AND DlSCUSSlON

The aoat reprosentativo loil in thi. area, on caleBreous sandstones, i5 red feraialitic, with A, BIt B2t t Sk' SCkt Ck profile (Caleie rhodoxeralfs or Cal­cie haploxer.lfa) affeeted by degradation procesaes (erosion, buring, hydromo~ phic}.

Erosion intensity varíes from poi~t to point and it may originate disposi­tion of the clayey B2t horizon and evory appoaranee of the urxJerlying ealcareous material. In any caao t depth at which this layer 8pp~ars ia ~le, as shown ir. transects of Fig. 2. Thia phenoll.enon is ob::erved alBo in plain zones.

In certain oce •• ions, in areas near sandy areas. the red soil is covered by a SIDld layer up to l 11. thiek. On the other hand , in dep~ion8 and also in lo wor part of horizona C, a hydromorphie proces8 ia develcped, changing the 80il colour frol!. red to yellow and finalIy endíng A8 a variagated hydromorphic har! zon mottled with red and grey apota (Aquic haploxerals). These hydromorphie

l'

1I

,1

106

Baila a180 appear in deepon long are aa li.itina the main broocka which, from North to south. drain imperfectly the zono.

When horizon B2t i. not longor prolent the Boil can. bti considerad al an i!!, ceptiaol, with a cambie horizon corresponding to tho tranaition Be (Calcixe~ líe xorochropts), or aa en entisol whon the Banda tORa is visible (Calcie xe­rorthents) •

To the North of the zono and in the alopoa ¡oinR dONn fra. the Aljarafe plateau to the Guadalquivir or tho Guadiamar valleya Tortonian marIa appear. Deep clayoy Baila ahow a groy-yollowish colour in wavy arOBS and grey to dark grey in de~ssions or plains. Thoy ahoN, in goneral, a atrona vortic charac­ter, less pronouncod in slopy aroas or at hill topa in which other caleareoua material from Pliocene appear. The darkar vertisol. can be Typic chrolllOlarerts or Entic palloxarerts and lightar onas Entic chromoxererte.

In the South of the considerad zone tho land ia hiaher giving w~ gradual ly to Quaternary or Plioquaternary (Villafranchian) formations with sand or gr! val and 80ila from those with no horizons (xarorthenta) to thosa strongly co~ traatad. Tha latter onea show a aandy pakt and &oma deep ~ horizons with old hydroaorphic proceS8 (Fragixeralfs). SOlllotim08, in plain zonos I tiese soila appear under a sane l ayer.

Finally thesa are tha soils of rocent fluvial apport forming the valleya of rivera Guadalquivir and Guadiamar (Xerofluvents) and t.l'.080 corresponding lo the first torrace of the Guadiamar which are grey-raddish, moderataly lixivi! tod (Haploxoralfs).

Resulta corresponding to physical propertios ol threa soils from a pilot zono within the area, are summarizod in table 1. Acolrding te tranR'Cts of Fig. 2, in the threo soils intermedi&te situationa aro found which com~to gradual ly tho tranaition from a soi1 to anothar. Resulta ahown (table 1) indieeto that textura of Caloie rhodoxeralfs iB tho m08t homoaonaous with dapth while on the eontrary Aquic haploxeralfs is tho 1II08t hoterogeneous, with maxillWl di! ferenees within extreme valuos of clay and sand ahowing two different layera, ono sandy. to a depth of 50 to 80 CI: and another moro clayoy from that dopth downwards . The soil Mollie haploxeralfa reprosent an intercediato situation.

Particle density ia in general high and this ia also the case with bulk donsity, probably duo to conditions undor which tholo 80ill aro found (tradi­tional olivo rielda). In prosont time many of thd80 zones aro tr~orm~d ,nd that originatos a dynamical ovolution of phyaical propartiea, aa has boen ahowr:. in a rocont wurk earried out in tho same zone (Moreno ot al. , 1985).

Hydraulie eonductivity shows valuas vory difforent according to soil and horizon cor,sidorod. For the most sandy on06 it ranaes from 1I0derate to high and in the c18yey ones tendE to be very alow. Water content at 1/3 and 15 bars show that in genoral soils considered havo an aceptable to good retention ca­paeity for available water. From a point of view atrictly agronomic, Calcie rhodoxeralf show the m08t equilibrated phyaical proporties.

So!l variety in this zono, and eonsequently diffarences in their physical proportioa are due to a great axtent to landacape. w~ havo found, aCtor a ay! telletic study, that water retention may be vory difforent in 80ih distant from

107

8 K : ¡",le 1.,1 ..... 1,: 13', Cale le Rl>crl .. .,.,11 - Calele llap1c.",lI: 19 r. ,Calele Hapl""nh -Calele iIIod ..... lI -Calele X ..... llu" ..

F19. 1 .- 111, of !lit dodlod .....

• " • " " '1 • ft • .. Calcic .

¡:Rhodoxe-ralt¡ N 1111",."11 s

Aquie H8plox~ralf

Molhc lIaploxeralf

~._" __ ~.~ __ ~"~ __ ~~. __ ~.~. __ ~~~ __ :.~ __ H:.~~.:. __ :'~~!' __ -=~~~I~~~~I~n~~I~~ __ ~I.~E~~~

• ~ .. ..

OJO

••

II!II RId .. 1I ~ Cclarecus _ terl:21

FlII. 2.- Sdlt:uUt r.;nsenhUan of lIJO tr:nlech In \h. pllat zen.

108

lobl. 1

Phy.lcal II"/I'U" of _ ,"proanuUy. IOn. In U. , ... (!:Inlrun .nd "",1"", y,"' .. fQllll\ In U. ¡n/n •• O -lOO .. dopth /

Partlcl ... ,ZI <21"(%/

2 - 311" (~I )31 po (1.1

ParU,1e don.II,{\J' ... .,)/ Mk ""',11y (\J' ... .,)/ SO ..... lod h,.n.\I, ,,,,<1.(00./1-1/ ~.I .. ,,,,ltnt .1 1/3 bar (,..11

• • 15 bar (;'v.n

22.5 - 32.8 2.5 - 5.5

61.5 - 7\.5 2.78 - 2.11: 1.56 - 1.71 3.0 - 16.3

22.3 - 32.3 U - 11 ••

7.0 - 35.0 \.5 - 7.0

sa.S - 81.5 2.16 - 2.82 1.52 - 1.61 1.0 - 65.0

11.1 - 31.0 3.1 - 1\.5

110111, IIIpl." ... II,

17.0 - 38.0 3.5 - 8.0

52.5 - 16.5 2.15- 2.18 1.\1 - 1.69 3.6 - 15.2

16.7 - 31.1 7.5 - ZI.l

eaeh othor only a few hundreda metora. Thoreforo, in pointa 25 (Calcie rhod2 xeralf.) and 12 (Aquic haploxeralfa) in t~t no. 1 (Fia. 2) and to • cepth af 50 C_, vol. water content are 14.4 ~ and 1.0 ~ reapoctivoly. durina the dr,( est poriad (July 1985). Undor 50 cm, paiot 12 ahow tho hiihoat vol. water con tent duo to the prosonco oi • paeudoaley horizon.

COHCLUSIONS

Tha area studied show up • ¡reat variety o( .oil& forming welI defined sa­quenees. These sequenco •• 1.0 appoar in yor.y roducod aro •• (10 Ha). which is tho cauaG af an important variability in the phyaical propartiea rf aoils, being Yory difficult the election of homoeeneoua zonoa for agricultural use.

ACKNOWLEDGEMENT

Thank. aro duo to Prof. Dr. J. 'Iartin Aranda for roviewing thc manuscript.

REFERENCES

CONFERENCE OH MEDITERRANt.AII SOILS (1966): Gula de la excul'sión •• pailola. !. 111-132. Spaniah Soil Sci. Soco

CONFERENCE ON MEDlTERRAHEAN SOILS (1966): Study Tour Through South.,·n Portu-gal, !' 94-99. Portugueses Soil Sei. Soco

KOREHO. F.. MARTlN-ARANDA. J.. KO~ST.\NK1EWICZ. K. and GOHEZ-ROJAS. F. (1986): Changos in Boíl physical and mechanical prtlpertioa duo to transfonaation frcDa dry farmine (olivos) tu irrigatioo (aonual cropa). Soil Tillage Res., 7: (in pr ••• ).