Takaya et al. - 1974 - Rice cultivation and its environmental conditions
Takaya et al. - 1974 - Rice cultivation and its environmental conditions
Takaya et al. - 1974 - Rice cultivation and its environmental conditions
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220 Y. TAKAYA, K. KYUMA, <strong>and</strong> K. KAWAGUCHI<br />
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2) Inl<strong>and</strong> V<strong>al</strong>ley near Badajoz<br />
This is the only example of rice l<strong>and</strong> situated inl<strong>and</strong> in the Iberian peninsula. The<br />
Guadiana river reve<strong>al</strong>s a braided feature at <strong>its</strong> middle reach when it comes out from<br />
high l<strong>and</strong> of Cambrian rocks to a saucershaped inl<strong>and</strong> basin of Tertiary rocks near<br />
Badajoz. Sever<strong>al</strong> terraces appear <strong>al</strong>ong <strong>its</strong> braided streams. Near stream portions form<br />
narrow strips of <strong>al</strong>luvi<strong>al</strong> plain with the relative height 1 to 3m from the stream bed.<br />
The sediments are composed of fresh gravel with a gray silty to clayey tops<strong>et</strong> bed<br />
sever<strong>al</strong> centim<strong>et</strong>ers thick. Outside this are situated other surfaces having a relative<br />
height 3 to 8 m from the stream bed. These have a yellowish-gray s<strong>and</strong>y top soil <strong>and</strong><br />
somewhat indurated red colored clayey underlay at a depth of sever<strong>al</strong> ten centim<strong>et</strong>ers.<br />
3) Albufera Lagoon<br />
The Albufera lagoon<strong>al</strong> portion is an ov<strong>al</strong> shaped sw<strong>al</strong>e s<strong>and</strong>wiched b<strong>et</strong>ween beach<br />
<strong>and</strong> dunes on the east <strong>and</strong> Quaternary terraces <strong>and</strong> older hills on the west. The silted-up<br />
portion of this lagoon forms a main rice l<strong>and</strong>. Sh<strong>al</strong>low v<strong>al</strong>leys pen<strong>et</strong>rating into<br />
Quaternary terraces, which appear like the arms of the lagoon<strong>al</strong> portion, are another<br />
rice growing area.<br />
The silted-up portion of the lagoon is flat <strong>and</strong> lowlying. This is in most places<br />
lower than 2m above sea level <strong>and</strong> some places are as low as to be protected by polder<br />
banks. Soils are dominantly clay. The pen<strong>et</strong>rating v<strong>al</strong>leys, on the other h<strong>and</strong>, are<br />
gently sloped, rich in coarser materi<strong>al</strong>s including gravels <strong>and</strong> encountered by c<strong>al</strong>careous<br />
bed rocks at relatively sh<strong>al</strong>low depth, though the main portion is still clayey. The<br />
silted-up portion of the lagoon is exclusively utilized for rice growing because of <strong>its</strong><br />
poor drainability. The v<strong>al</strong>ley portion, on the other h<strong>and</strong>, has a mosaic pattern of rice,<br />
veg<strong>et</strong>ables, <strong>and</strong> citrus trees .<br />
.J) Ebro Della<br />
The Ebro delta has three physiographic un<strong>its</strong>; levee, backswamp <strong>and</strong> coast<strong>al</strong><br />
marsh-beach complex (Fig. 7). The levee is an elevated zone <strong>al</strong>ong the present <strong>and</strong><br />
Q Levee<br />
U Backswamp<br />
~ Marsh <strong>and</strong> beach<br />
(SJ Tt•l'l'nce <strong>and</strong> hill<br />
14·17 Sampling sites<br />
Fig. 7. Simplified physiographic map of the Ebro delta, Spain; simplified from BAHR ( 8, 9 ),
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