Summer agrestal vegetation of dryland crops in Spain

JOSE WIS CARRETERO (-1"1'1»

ABSTRACT

CARRETERO, J. L. (1995). Summer agrestaJ vegetation of dryland crops in Spain. Candollea 50:195-216. In English, English and Spanish ahstracts.

A synlaxonomic study of summer-autumn agrcstal communities, bdonging to the Diplolaxionerucoidis alliance, of dryland crops in the Peninsular Spanish Mediterranean Region. is presented.Phytosociological tables ofall the syntaxa arc given. as well as floristie, ehorological, biogeographicaland e<:oJogical data. Onc association: Chenopodiolllbi-Amaranthetum blltoidis and two subassocia­lioos: Eragrostio mojoris-Chenopodietum botryosamaranthelosum bliloidisand Amarantho de/ilei­Dip/ataxie/urn erucoidisarnaranthefosum bliloidisare described as Pev.'. On the basis ofthe 300 fieldssurveyed. the frequency. abundance (partial cover percentage) and gmde of infestation (global coverpercentage) of each important weed are analy"lcd. The most aggressive agrestals are Amaranthusbliioides, Amaranlhus a/bus, Dipla/axis erueoides, Chenopodium album, Convolvulus arvensis,HeJiolropium europaeum, Sa/sola kafi. Chrozophora linetaria, Cirsium arvense, Cynodon daelylon,Amaranthus retroj1exus, Chondril1a juncea and Chenopodium vulvaria. among many others.

RESUMEN

CARRETERO, J. L. (1995). La vegclaci6n arvense de vemno en los cultivos de sccano de Espaiia.Cando//ea 50; 195-216. En Ingles, resumenes en IngU:s y EspanoI.

Se presenta un estudio sintaxon6mico de Ins comunidades arvenses de verano-otoi!o, pertenecientesa la alianza Diplotaxion erucoidis, en los eullivos de secano de la regi6n mediterranea de la Peninsula1bcrica. Se publican !as tablas fitosociol6gicas de todos los sintixones, nsi como datos flor!sticos,oorol6gicos. biogcogcificos y ecol6gicos, Son dcscrilns como nuevas: una asociaci6n. Chenopodioalbi·Amaranlhetum bliloidis, y dos subasociaciones, Eragroslio majoris-Chenopodielum bolryosamaranlhelosum bli/oidis y Amarantho de!ilei-Diplotaxielum erucoidis amaranlhelosum bliloidis.Sobre la base dc 300 levantamienlos de campo. se analizan la l'recuencia, la abundancia (porcentajede cobcrtura parcial) y grado de infestaci6n (porcentaje decobertura global) de cada una de las espe·cies mas importantes. Las arvenses mas agresivas son: Amaronthus bliloides. Amaranlhus albus,Dip/ofaxis erucoides, Chenopodium album, Convolvulus arvensis, Heliolropium europaeum, Sa/­soJa kali, Chrozophora tineloria. Cir·sium arvense. Cynodon daclylon, Amaranlhus rerroj1exus,Chondri/la juncea y Chenopodium vu/varia, entre otras.

KEY-WORDS: PhYlosociology - Weed communities - Diplotaxion erucoidis - Syntaxonomy­Iberian Peninsula.

Introduction

The area surveyed (Fig. 1) compris~ all the Spanish Mediterranean chorological region, exceptBalearic Islands; that is to say the major part of the Spanish Iberian Peninsula.

The soils may be described as generally siliceous in the western half and calcareous. with somesiliceous enclaves, in the eastern half.

CODEN:CNDLAR50(l) 195 (1995)

ISSN: 0373·2967

CONSERVATOIRE ET JARDIN

© 80TANIQUES DE GEN£VE 1995

196 CANDOLLEA 50, J995J. L. CARRETERO - SUMMER AGRESTAL VEGETATION OF DRYLAND CROPS IN SPAIN

Three types of bioclimate may be distinguished (Fig. 1):

197

Fig. 1. - Study area with the biodimatic stages according to RiVAS·MARTfNEZ (l987a).

~ Therrnomediterroneon

i~t#*j Mesomediterranean

~ Supramediterranean

.......~..... ... ,.... .~ ...........

1. Northern Meseta2. Central Mountains3. Iberian Mountains4. Ebro Depression5. Southern Meseta6. Guadiana Plain7. Guadalquivir Valley

1) the Thermomediterranean bioclimate of the coastlands and the GuadalquivirDepression;

2) the Mesomediterranean bioclimate of the Southern Plateau (Southern Meseta). with itsneighbouring zones•.and the Ebro Depression; and

3) the Supramediterranean bioclimate of the Northern Plateau (Northern Meseta) and theCentral and Iberian mountain Systems.

The average temperatures of the year of these bioclimates are, respectively. higher than 17Q C,from 13°C to 17 Q C and lower than 13°C. In the Guadiana (Extremadura), Guadalquivir (WesternAndalucia) and Ebro (Arag6n) Depressions, and in some points of the Southern Plateau, the aver­age of the maxima of the hottest months (July and August) varies from 32Q C to 36 Q C.

The annual rainfall is variable and scarse throughout our territory. It does not reach 300 mmin the southeastern regions and only exceeds 700 mm in some mountainous zones. In summer, theSouth has minimum prccipitations. not reaching 50 mm in most localities.

Summer-autumn agrestal vegetation ofdryland crops (vines. almonds. olives, sunflowers, ete.)and ofsome irrigated crops (sugar beets, melons, watermelons. fruit trees. ete.) with low soil humid­ity is widely spread throughout the agricultural areas of the Spanish Mediterranean region. It cor­responds to the Diplotaxion erucoidis alliance.

When Braun-Blanquet (BRAUN-BLANQUET & al.. 1936) describes the Diplotaxion alliance,in spite of the fact that its characteristic species are for the most part ofsummer-autumn phenology.he includes the vegetation developing in the course of over the year (specially in his associationDiplotaxiserucoides-Amaranthus delilei = Diplotaxietum erucoidis). The criterion of consideringthe winter-spring vegetation as pertaining also to the Diplotaxion has been followed by the majorityof latter authors (QUANTIN. 1947; BRAUN-BLANQUET & al.• 1952; BRAUN-BLANQUET &BOLOS. 1957; SCHUURMANS STEKHOVEN. 1961; MOUITE, 1964; BOLOS. 1967; RIGUAL.1972; BRULLO & MARCENO, 1980; FOLCH, 1981; BOLOS& VlGO. 1984 and NEZADAL. 1989;among others). Although some authors (RIVAS GODAY, 1956. 1964; RIVAS GODAY & RIVAS­MARTiNEZ. 1963; IZCO, 1975) already considered the Dip/otaxion alliance exclusively ofsummer-autumn phenology, BRULLO & MARCENO (1985) are the first that created the Fumarionwirtgenio-agrariae alliance for including the winter-spring communities. In our opinion. this lastcriterion seems to be appropriate, since in our Mediterranean climate there is a clear differentiationbetween the winter-spring and summer-autumn species (with some rare exceptions. as Diplotaxiserucoides that grows during all the year).

BRULW & MARCENO (1980) segregate in the Chenopodion botryos alliance all the calci­phobe communities. maintaining only the calcicolous ones in the Dip/otaxion. As the soil charac­teristics (Table 6) do not play a determinant role in the typification of the most Diplotaxioncommunities. we do not consider adequate (at least in Spain) the separation of the two above men­tioned alliance.

Many times. the Dip/otaxion and Eragrostion alliances (originally described in Western andEastern Europe, respectively) have been confused. TUXEN (1950) considered theDip/otaxion sensuMorariu 1943 non Br.-B!. 1936 and the Eragrostion as synonyms. the Eragrostion being subordi­nated as a thermophile suballiance to the Panieo-Setarion alliance Sissingh in Westhoff, Dijk. Pass­chier 1946. Tuxen, however. considered the mediterranean Dip/otaxion Br.-Bl. 1931 to be separatedfrom the thermophile part of the Panico-Setarion. RIVAS GODAY (1956, 1964) induded also theEragrostion as a suballiance into the Panieo-Setarion. but here with the Diplotaxion Br.-Bl. 1936as a synonym of the Eragrostion.

TUXEN & OBERDORFER (1958) place the Spanish association Setaria glauea-Echinoeh/oae%na in the Eragrostidion suballiance of the Panieo-Setarion. with no reference to Diplotaxion.POLl (1966). MAUGERI & LEONARDi (1974). MAUGERI (1980) and MAUGERI & al. (1980)include both the Diplotaxion and Panieo-Setarion Sicilian communities into the Eragrostion.LACOURT (1977) indicated that the Eragrostion and PanieD-Setarion must not be maintained asindependent alliances and he places them, without any syntaxonomic rank. in Diplotaxion. IZCO(1975) and RIVAS-MARTiNEZ (1987b) consider the Eragrostion partially contained in Diplo-

198 CANDOLLEA 50, 1995J. L. CARRETERO - SUMMER AGRESTAL VEGETATION OF DRYLAND CROPS IN SPAIN 199

1 2 3 4 5 6 7 8 9 ro nUB U B M 17 M~~nm~~~~Em~n~~nMn~

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Characteristics of association and alliance

Nr. order.Cover %

Amorunfhus olbusHeliotropium europaeum ..Chenopodium botrys ..Tribu/us terresJris •.•...••....••..Salsolo kali .Eragrostis barrelieri .Diplotaxis erucoidesSetaria viridis " . , .Diff. suba~ociationAmaranthus bUtoides .. ,.Chrozophoro tinetorio.Cyperus rotundus ..Panico-Selarion

Solanum nigrum ...•.• , ..•.•.•••.••..Amaranthus rctrojlexus . •..•••.••Porfu!oco o!eraeea .Ruderali-Secalietea

Chenopodium album. , ..Convolvulus arvensis.Cynodon dacty!on ..Chondrilfa juneea .Xanlhium spinosumChenopodium vulvaria •• , ..••..•• , , .••.LoUum rigidum .. , .••.. ,. •.• ,.Cirsium arvense .Sonehus oleraceus ••.•.....!.actuca serriolo ..... ,.. . ..... ,..... 1.1Anacyclus clavatus . +Pal/opia convolvulus .Euphorbia chamaesyce •..Conr..a canadensis . ......•.....

taxian. RIVAS-MARTiNEZ (1977) and BRULLO & MARCENO (1980) subordinates the Eragras­lion to the Panteo-Se/orlon; these authors and also OBERDORFER (1954), KOJIC (1975) andNEZADAL (1989) maintain the independence between the Eragrostion and Diplotaxion alliances.NEZADAL (1989), in his study about the Iberian spring weed vegetation, includes the autumn~

winter-spring communities on loamy soil in Dip/otaxion and the summer-autumn-winter ones onsandy soil in Eragrostion.

As a result of the reading of all this bibliographical information, and also ofsome of the mostsignificantp~rs referring to Central and Eastern Europe (TUXEN, 1950; OBERDORFER, 1954,1983; KOVACEVIC, 1970; BRULLO & MARCENO, 1980; ELL~S. 1983; KR1PPELOVA, 1984;KRIPPELOVA& MUCINA, 1988, KOROTKOV &a1., 1991), in addition to our own field observa­tions, we consider the inclusion of the greatest part of the Eragrostion vegetation (in spite of thepresence ofmore thermophile taxa) in the Panico-Setarion alliance as the most convenient, withoutstablishing any lower syntaxonomic status, as generally the position of the summer agrestalcommu~nities of the irrigated crops. at least in Spain, in one or another alliance would be very difficult.On the other hand, according to the rather xerophile characteristic taxa (Heliotropium europaeum,Amaranthus albus, Salso/a kali. Amaranthus blitoides. 'Uagus raeemosus, Tribu/us terrestris, etc.)of those indicated in the Eastern European Eragrostion, the inclusion of part of this alliance inthe Dip/otaxion would not be incorrect.

As conclusion of all above observations, we believe that the Spanish Mediterranean summer­autumn agrestal weed communities. on any soil type (sandy, loamy. clayey, limy or siliceous). mustbe distributed between the Dip/otaxion in dryland crops and the Panieo-Setario in irrigated crops.

The Diplotaxion communities are agrestal pioneers of summer-autumn phenology, formedmainly by therophytes. and some other geophytes and hemicryptophytes. that grow in dry or sub­humid, ploughed, sunny, and generally slightly nitrogenous soils. In our territory, their characteris­tic species are: Amaranthus a/bus, Amaranthus blitoides, Chrozophora tinetoria, Dip/otaxiserueoides. Heliotropium europaeum, Sa/so/a kali. Tribu/us terrestris, Setaria viridis, Eragrostisbar­relieri, Sorghum ha/epense. Chenopodium botrys, Erueastrum nasturtiifolium. Xanthium orien­tale, ete. This type of vegetation has been object of many scientific publications in Spain(ALCOBER, 1983; BEDIN & ZARAGOZA, 1981; BOLOS, 1962, 1967; BOLOS & BOLOS, 1950;BURGAZ & SAIZ, 1989; CARRETERO, 1989; DfAZ & PENAS, 1984; HIDALGO & aI., 1990;IZCO, 1975; LADERO & aI., 1983; MASALLES, 1983; MENDIOLA & OLMEDO, 1987;NAVARRO & VALLE, 1984; PEINADO & aI., 1985; PUJADAS & HERNANDEZ-BERMEJO,1988; RIVAS GODAY. 1956, 1964; SAAVEDRA & al.. 1989; among others), but the studies havealmost always been incomplete or refer to limited areas_ The aim of the present survey is to analyzethe agrestal syntaxa found by personal investigation of the author in the Spanish Iberian Peninsula.

Material and methods

Over the last twelve years 300 phytosociological releves of 100 m 2 have been carried out inthe Spanish agrestal Diplotaxion vegetation. according to the Braun-Blanquet method (BRAUN­BLANQUET, 1965; GEHU & RIVAS-MARTfNEZ, 1981). Sixtytwoofthem were chosen for tables1 to 4. defining the respective communities.

In order to evaluate the importance of the different weeds in the established syntaxa (Thble5) and in the whole of the 300 releves (Table 7). the following has been determined for each species:the frequency (percentage of releves where the species is present). the partial cover percentage (rela­tionship between the sum of the aveI'2.ge cover percentages and the number of releves where thespecies is found). and the global ortotal cover percentage (relationship between the aforementionedsum and the total number of releves. always of the corresponding syntaxa). The abundance­dominance signs have been transformed into average cover percentage in the following way: +0.5"10, I ~ 2.5%,2 = 15"70, 3 ~ 37.5%, 4 ~ 62.5%,5 = 87.5%.

Other species - Panico-Setarion: In 2: Amaranthus graC'Cizanssubsp. silvC$tris 1.1; 5: Dalu"!~lramonium+: l~: Am"!ran­thus hybridus +; 13: Digitaria sanguinalis 1.1; 16: Eragrostis ciUanens~s 1.1; 17: Setaria vertu:lllata +. Rudemh-Se~letea- 1: Chamaeme!um mixtum +; MaIvo sylv(!$1ris +; Senecio vulgariS +; 4: Mafva neglecta +; Polygonum rurlvagum1.1; 5: Vicia benghalensis 1.1; 7: Linaria spartea +; 9: Rumex bucephalophofUS subsp. gallicus +; 10: Avena sterilis 1.1;Diplolaxis virgat(J 1.1; Papaver rhoeas 1.1; 11: Euphorbia serrata +; 15: Chenopodium murale +; 17: Kickxia lanigera+; Sonchus asper I.l; 18: Vaccaria hispanica 1.1.Localities. crops and dates: I. Jacn: La Carolina, olives, 4.7.82; 2. Zamom: Villamayor de Campos, sugtU" beets, 19.8.82;3. Valladolid: Vega Sicilia. vines. 19.8.82; 4. Soria: Novierca5, 5unOowers. 19.8.82; 5, GuadaIa;ara: El Pobo de Duenu.sunOowers,21.8.82; 6. Scgovia: Zarzuela del Monte, potato5. 8.10.82; 7. Pal:mcia: Ledigos. vines, 15.8.83; 8. C:iceres: Almo­harin, w:ltermelons. 10.8.83; 9. Avila: El Tiemblo, vines., 31.7.86; 10. &villa: Dos Hermanas, safnower, 5.6.82; 11. Tcruel:Bagucna. vines, 17.8.82; 12. Navarra: Mila8ro. sugar beets. 18.8.82; 13: Albaeete: Almansa, corn, 21.9.82; 14. Ciudad Real:Manzanares. vines. 3.10.82; 15. Hue1va: Cartaya, corn, 20.6.83; 16. Valencia: Saldovar, vines, 28.9.85; 17. Malaga: Ante·quem, onions, 19.8.89; 18. Cuenca: Sisante-Rubie1os Bajos, sunOowcrs, 20.8.89.

Table I. -Eragroslio mojoris·Chenopodictum botryos Br.·B!. 1936amoronlhetasum blitoidissubass. novo (Holotypus: reI. 11).

200 CANDQLLEA SO, 1995 J. L. CARRETERO - SUMMER AGRESTAL VEGETATION OF DRYLAND CROPS IN SPAIN 201

Nr. order ....Cover % . 1 I 2 I 3 t 4 t 5 t 6 17 I 8 t 9 I10 I JJ 112 113 114 115 1/6 1" t 18

M~~~M~~~~~n~~~~~~~

Thble 2. - Kickxio lanigerae-ehrot-ophoretum tinctoriae Rivas Goday l,")( Izeo 1975.

Other species - Panico-Setarion: 6. Digilariasanguinalis +; Echinochloaealonum +; Setaria verticillata 1.1; 9: Portuiacaoleracea 1.1; Ruderali-Sccalietea -1: Anacyc/usradiatus 1.1; Anehusaaz;urea 1.1; Chenopodium murale 1.1; Polygonummurivagum +; Pulicaria paludosa +; 2: Papaverrhoeas +; Vacearia hispaniea +; 3: Euphorbia serrata +; 6: Polygonumaviculare 1,1; 9: Anaga/iis faemina I.l; Capse/ia rube/ia 1J; Phalaris minor 1.1.Localities, crops and dat~ I. Badajoz: Olivenza, chickpeas, 6.6.82; 2. Scvilla: El Arahal, sunflowcrs, 5.7.82; 3. Albacete:Albaccte-Baylazote, sunflowers, 14.8.82; 4. C6rdoba: Posadas-La Clrlota, sunflowcrs, 18.8.82; 5. Zamgoza: La Almolda,sunflowers, 20.8.83; 6. Ja61: Solana de Tormlba, sugarbccts, 2.10.82; 7. Ciudad Real: Santa Cruz dc Mudela·Yaldepeilas,sugar beets, 30.10.82; 8. Guadalajara: Armuila de Thjuila, sunflowers, 9.10.82; 9. C:'tdiz: Yentadcl Cuervo-Jerez de la Fron­tern, cotton, 21.6.83; 10. Thledo: ViIlasequilla de Yepcs. vines, 30.7.86.

Characteristics of association andalliance

Chroz,ophora tinctorio ..•..••.. 'I 2.1Amaranthus a/bus _ .. _. . .••. I.IHeliofropium europaeum. ••. . I.lAmaranthus bUta/des •••• __ _. 1.1Kickxia lan/gera ..•. ..•..•.Physalis philadclphica •••.Salsolo kali .•. .. , •••....So[unum vifJosum .•••••••Tribulu$ tcrrcstris ..• . . " ... I 1.1

PanicO"-SctarionDaturastramonium•••..•....... I +Amaranthus hybridus • .••••••..Amaronthus relroj1= .Solanum nigrum . _.•..•..••.

Ruderali-Seca1ieteaChenopodium album ..•••••... _ I I.IConvolvulus arvensis ..Chenopodium vulvaria ••. _.....•Cirsium arvense . .•...Diplo/axis virguto ••..•...•....•Sonchus oleroceus •. .••.•......•Cynodon dactylon . ...••..... -' '11.2Euphorbia chamaesyce.......... 1.1Hirschfcldia incana............. +Lactuca serriola................ 1.1Chondri//a juncea ••••••••...•••Xanthium spinosum ••••.•....•.

Other species - !'anico-Setarion, 4: Digitaria sanguinaUs 1.2; 5: Setaria adhaerens 1.2; 6: Amaranthu$ graecizans subsp.si/vestris 1.1; 10: Setaria vertiei//ata 1.1; 18: Daturastramonium 1.1. Ruderali-Secalictea,l:Foeniculum vulgaresubsp.pipe­rUum +; 2: Cichorium intybus +; Erucasativa +; Glauciumeomiculatum +; Polygonum rurivagum Ll; Rapistrum ruga­sum 1.1; Rcseda lutea +; 3: Polygonum bel/ardii 1,1;4: Bidenssubalternans 1.1; 5: Diplotaxismuralis Ll; Mercurialisannua+; 6: Conr..a bonariensis +; 7: Sonehus tenerrimus 1.1; 10: &ssiascoparia +; 12: Anacyclusclavatus 1.1; Senecio vulgaris1.1; Sisymbrium irio 1.1; 13: Amaranthus viridis 1.1; Moricandia arvensis 1.1; Zygophyl/umjabago 1.1; 14: Cardaria draba1.2; Chenopodium murale +; IS: Aster aquamatus +; Conr..a sumatrensis 1.1; 16: Diplotaxis virgata !.I; Hirschfeldiaincana LI; Papaver rhocas +; Vacearia hispaniea +.Localities, crops and datcs - I, Navarra: Castcj6n, vines, 18.8.82; 2, Hucsca: Almudevar, sunnowers, 12.8.84; 3, Urida:Tarrc:ga, sunflowers, 17.8.82; 4. Barcelona: Yillafranca del Penedes, vines. 17.8.82; 5, 'Thrragona: Altafulla, hazelnuts,8.11.82; 6, Castc1l6n: La PeIcchana, almonds, 4.10.83; 7, Valencia: Higucruclas, almonds, 27.8.89; 8, Cuenca: Et Provencio,sugar beets, 1.8.82; 9, Madrid: Fuentiduena del Thjo, corn, 29.7.85; 10, Alicante: ViJlena, vines, 28.7.89; n. Albacete:Cancarix, vines. 3.8.85; 12, Alicante: La Mata, vines. 23.6.90; 13. Murcia: La Union, oranges, 3.7.84; 14, Almcna: Vera,lemons. 23.6.83; 15, Jaen: Andujar, plums, 4.7.88; 16, SevilIa: AlcaMde Guadaira, olives, 5.7.82; 17.Ciudad Real: Daimiel.vines, 5.10.82: 18, Zaragoza: Alfajann, sunOowers, 27.8-83.

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Characteristics of association and allianceAmaranthus blitoides ....Hdiotropium europaeum .Diplotaxis erucoides .Tribufus terreSlris ..Salsola kafi .Sorghum hafepense ..Setaria viridis . . ...Chrozophora tinetoria.Amaranthus albus .Eragrostis barrefieri .Erucastrum nasturtiifoHumSolanum villosum .Tagetes minuta .

!'anico·SetarionPortulaca oleracea .Cyperus rotundus .Amaranthus retrojlexus.Amaranthus hybridus

Rudcra!i·S=!icteaChenopodium album.Convolvulus arvensis ..Cynodon dac/ylon .Chondri/la juncea •..•...•••....••.••..Cirsium arvense ...•...wlium rigidum .... . ...Sonehus leraceus .Xanthium spinosumLactuca scrriola ..Chenopodium vulvaria .Euphorbia serrataBeta maritima . ...Atriplcx patula •.

+

+

+

+

1025

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945

+

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740

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235

2.1

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140

Nr. order ..• _•.•••...Cover %.

Thble 3. - Chenopodio afbi·Amaranthetum bUtoidis assoc. novo (Holotypus: rei. 12).

202CANOOLLEA 50, 1995

1. L. CARRETERO ~ SUMMER AGRESfAL VEGETATION OF DRYLAND CROPS IN SPAIN 203

Thblc 5. - Frequencies (F), and partial (PC) and global (GC) cover percentages of the most important species of the SpanishDipfolaxion communities (see explanations in the text). Aa: Eragrostio-Chenopodietum botryos chenopodletosum botryos;Ab: E.-Ch. b. amaront!tetosum bfitoldis; B: Kickxio-Chro;:ophoretum tinetoriae;C: Chenopodio-Amaranthctum blitoidis; D:

Amarantho-Dip/otaxietum erucoidis; n: number of releves.

Other species Panico-Setarion, 8: Amaronthushybridus 1 l'A h " ..si/vestris 1.1; 16: Cyperus fOtundus1.l. RUderali-Secalieteu i:p'nu:r~'!t us.p.owe 1I1.I; lI:Am?,ranthusgroeci::.allSsubsp.presso +; 5: Po/ygonum avicu/are 1 I' Sinapis arvellSis .;.. 6':~ le~cI011e;s +; 2: Anagc:/lIsarvellSis 1.1; 3: Poacom-·amplexicau/e 1.1; Rumexcrispus +. So~chuso/eroceus+. 8: :/ a va sy ~es rlS +; 7; Erodlum cicutarium 1.1; Lamiumvu/gare subsp. piperitum +; 12; Eruca veslcaria +. 23' 'T;i:~:~~m m:f1anu';l1.~; 9: ~o,!y-..pC(l,!ad~n:is +; Foenicu/umLocalities, crops ~d dates _ I GerontC Fi ' . • a poycerolla +. 14. DlplotOXlS Vlm/nea +.Murillo de GaIlego. olives, 12.8.87; 4. Thrrng~~~ri:;.I~ifv·86;829~lona; RU~i. almonds, 30.8.85; 3. zarngoza:19.8.88; 6. Zar:lgoza: Cariil.ena, vines 14 8 88' 7 . . es, •• 2. 5., Teruel; Vlliafrnncn del Campo, sugar beets.17.10.83; 9, Navarra; Castej6n vin~ 12 SsS. 'l~ns~!~n; ~lI~ra.ncade1 Cid. potatO$, 4.10.83; 8. Valencia; Utiel, alfalfa~onds. 4.10.83; 12, Madrid: CastilJeJo: vines: 9.~.~ l~rJ~lan?iavines, 27.8.89; U, Cll.steIl6n: Pobla Torn=:Hlguerue!as, almonds,. 30.9.89; 15 Valencia: Paterna vines 2' 82;e?C<C16 Al' PObl~tav: almonds,. 12.10.91; 14. Valencia:

• " •. • lcante. 111ena. garlics, 28.7.89.

Amarontho deMel-Dlplot(1JCletum erucOldlS Br.-BI. ex Bo.·BI. 1936• . amaronthetosum blitoidis subnssoc. novo

(Holotypus: rel. 14).

12 34567891011121350 55 55 70 35 70 45 50 45 60 65 60 70 ~~ ;; ;g

A, n: 50 Ab n; SO B n: 50 C n: 100 D n: 50

Diplotaxion erucoidis F PC GC F PC GC F PC GC F PC GC F PC GCAmaranlhus a/bus. 86 14.66 12.61 96 11.72 11.25 56 9,34 5.23 20 1.20 0.24 18 4.83 0.87Amarantus bliloides •. - - - 84 9.43 7.92 44 8.16 3.59 " 19.69 18.70 28 8.46 2.37Helio/ropium

europaeum •••. . .... 50 5.74 2.87 42 6.69 2.81 76 7.20 5.47 23 1.98 0045 12 1.83 0.22Diplotaxis erueoides .. - - - 14 1.93 0.27 6 1.83 0.11 31 2.52 0.78 96 22.56 21.66Chrozophora tinetoria . - - - 10 1.70 0.17 % 10.39 9.98 7 2.21 0.15 2 2.50 0.05Sa/so/a kali. .. ........ 14 4.29 0.60 24 6.33 1.52 16 1.50 0.24 41 11.06 4.53 , l.83 0.11Tribulus lerreSlris . 34 3.12 1.06 18 3.67 0.66 8 5.12 0041 15 3.07 0.46 6 6.00 0.36Setaria viridis•... 12 1.33 0.16 8 2.00 0.16 - - - 12 5.46 0.65 22 4.59 1.01Eragrostis barrelieri ... 6 1.83 0.11 10 1.70 0.17 2 2.50 0.05 16 3.03 0.48 16 3.31 0.53Sorghum ba/epense .•.• - - - 2 2.50 0.05 4 8.75 0.35 14 5.04 0.70 18 4.83 0.87Chenopodium botrys .. 28 4.00 Ll2 6 1.83 0.11 - - - - - - - - -Erucastrum naslurtii-

folium .•..•••.••... - - - 2 0.50 0.01 2 2.50 0.05 6 1.83 0.1I 24 11.50 2.76Xanthium arien/ale.. 4 8.75 0.35 4 2.50 0.10 6 1.83 O.ll 6 2.50 0.15 4 2.50 0.10Kickxia lanigera ..•.•• - - - 2 2.50 0.05 18 3.22 0.58 2 1.50 0.03 - - -Solanum villosum . ... 6 2.50 0.15 4 1.50 0.06 4 1.50 0.06 4 2.00 0.08 2 0.50 0.01Tragus racemosus. ... - - - - - - - - - 4 5.12 0.20 2 0.50 0.01Chro:.:ophora obliqua .. - - - - - - 6 1.83 0.11 - - - - - -Tageles minula ..•.. - - - - - - - - - 3 6.00 0.18 2 0.50 0.01

Panico-Setarion

Amaranthus retroJkxus 2' 4.27 1.11 2' 3.46 0.90 8 5.12 0.41 29 4.79 1.39 36 3.78 1.36Portu/aca oleracea "" 18 2.28 0.41 24 3.37 0.81 , 1.83 0.11 24 2.69 0.64 28 2.82 0.79Solanum nigrum .••.•. 32 2.37 0.76 16 2.00 0.32 10 4.60 0.46 7 2.21 0.15 4 2.50 0.10Cyperus ro/undus . - - - 20 2.30 0,46 4 2.50 0.10 14 4.00 0.56 6 2.50 0.15Amaranthus hybridus.• , 6.00 0.36 6 1.17 0.07 12 1.83 0.02 9 228 0.20 10 210 0.21Datura stramonium ... 12 1.33 0.16 4 1.50 0.06 4 LSO 0.06 5 4.60 0.23 4 2.50 0.10Amaranthus graeei::.ans

si/ves/ris ... ..... 6 1.83 0.11 6 1.17 0.07 - - - 8 2.25 0.18 6 1.83 0.11Digitaria sanguina/is ... 6 1.17 om 4 0.50 0.02 6 1.83 0.1l , 1.83 0.11 4 1.50 0.06Setaria verticillata .•. •• 2 2,50 0.05 8 2.00 0.16 4 1.50 0.06 8 5.37 0,43 2 2.50 0.05Setaria adhaerens ..... - - - , 1.83 O.ll 4 LSO 0.06 7 2.21 0.15 6 6.67 Q.40Amaranthus powellii •. 10 1.70 0.17 6 6.00 0.36 - - - 3 2.50 0.07 2 0.50 0.01Echinochloa c%num - - - 2 0.50 0.01 2 0,50 0.01 3 1.83 0.05 2 0,50 0.01£ragrostis cilianensis .. 4 LSO 0.06 2 2,50 0.05 - - - - - - - - -Ruderali-Secalietea

Chenopodium aibum .. 74 5,43 4.02 72 7.87 5.67 62 7.50 4.65 66 4.18 2.76 60 4.8<) 2.88Convolvulus arvensis .• 50 4.50 2.25 38 7.92 3.01 52 4.19 2.18 " 5.72 3.26 56 5.39 3.02Chondrt1/a juncea .•... 60 2.80 1.68 20 3.35 0.67 18 2.05 0.37 35 1.93 0.67 36 4,47 1.61Cynodon daety/on ... 28 5.89 1.65 38 3.82 1.45 30 4.03 1.21 27 4.67 1.26 24 4,42 1.06Cirsium arvense. ....•• 38 2.84 1.08 14 9.00 1.27 22 5.36 Ll8 28 4.52 1.26 40 8.52 3.41Chenopodium vu/varia 26 3.31 0.86 24 4.42 1.06 28 4.29 1.20 12 5.46 0.65 12 6.67 0.80Xanthium spinosum ... n 2.31 0.76 8 LSO 0.12 26 2.04 0.53 21 2.90 0.61 14 3,43 0.48Sonchus o/eraeeus. 14 2.21 0.31 18 2.28 0,41 12 3.67 0.44 20 2.00 0.40 16 3,56 0.57Euphorbia serra/a. 6 1.17 om 6 t.17 0.07 18 0.94 0.17 12 L50 0.18 10 1.70 0.17Lactuca serriola . ...... 12 4.25 0.51 10 2.10 0.21 18 2.67 0,48 8 2.25 0.18 4 1.50 0.06Lotium rigidum .•. .... 16 3.81 0.61 10 2.50 0.25 10 2.10 0.21 9 2.06 0.18 4 1.50 0.06Polygonum rurivagum • 16 2.00 0.32 6 Ll7 0.Q7 6 1.83 0.11 5 2.10 0.10 8 2.00 0.16Anacyclus c1avalus .. 14 2.21 0.31 6 0.50 0.03 8 1.50 0.12 8 1.75 0.14 4 2.50 0.10Dip/otaxis virgala ..••• 4 2.50 0.10 14 1.')3 0.27 16 3.81 0.61 4 5.12 0.20 2 2.50 0.05Medicago saliva ...... 8 2.00 0.16 12 l.83 0.22 , 0.50 0.03 8 2.00 0.16 6 2.50 0.15PapOVer rhoeas . ... 12 1.83 0.22 14 1.64 0.23 6 t.17 0.07 1 2050 0.02 4 1.50 0.06Sonchus tenerrimus .. 4 LSO 0.06 4 1.50 0.06 4 1.50 0.06 15 1.70 0.2$ 10 1,70 0.17Euphorbia chamaesyee. 10 2.10 0.21 4 1.50 0.06 16 3.56 0.57 3 1.17 0.03 2 2.50 0.05Chenopodium muro/e. 4 1.50 0.06 12 3.92

1

0.47 6 1.83 0.11 S 0.90 0.04 4 2.50 0.10Po/ygonum avlcu{are . 10 J.70 0.17 4 1.50 0.06 6 1.83 0.11 2 1.50 0.03 8 2.00 0.16Hirschfeldia incana. ... 2 0.50 om 6 1.83 0.11 10 2.10 0.21 6 L50 0.09 2 2.50 0.05Daucus carota .. 2 0.50 O.Ol 4 1.50 0.06 4 1.50 0.06 6 1.83 0.11 6 1.17 0.07

1.2

2.1

1.1+

+

UI.l+ LJ

1.1

+

+

+

+

+

+ l.l2.2 1.22.2 Ll +2.2

2.2

1.1

+

+

++

2.2

3.1 3.1 3.1 2.1 3.3 2.1 4.4+

1.2

l.l +1.1

I.1 l.l U 2.1 I.1 2.1 U \,l

LI +

1.11.1

1.11.1

2.1 2.1 2.1 3.1 +2.11.1

I.ll.ll.I

1.2 1.2

1.1

I.l 2.1 1.1 I.1 I.1 l.l2.2 2.2 1.2 I.1l.l 1.1 1.1l.l 1.1 l.l

1.2

1.1++

1.1

1.2

2.1 3.1 2.1 2.11.I 3.1

1.1 1.11.2+

1.1

1.1+

+1.11.1

+

2.l LI

2.1 1.1Ll 1.2 1.21.1 1.1

1.11.2

Nr. order .. ' •..•• _.•• ,.Cover % .•

Characteristics of tlSsociation and allianceD/plo/axis erucoldes. . .Erucasfrum nasturltifolsumSetaria vindis •_•.•..Sorghum ha!epense.••Tribulus terrestris .Amaranthu$ a/bus .•. ... " ..Heliotropium europaeum •.•.Eragrostis barrelieri .....•.Salsola kali .Xanthium orientale

Dife subassociation

Amaranthus blftoides ..

Panico-Setarion

Amaranlhus retroflexusPortulaca oleracca ....

Ruderali-Seealictea

Chenopodium album •..Convolvulus orvensis ..••.•...•Chondri/kt juncea •. .••..•.••••efrs/urn arvense ...••••...•.•.Cynodon doctyJon •.•••..•..••• .Lobu/aria mortllma. ..•. . . •. ....• • ~.

Daucu$ carota. . •. •.••• """ .•.•Sonchus tenerrimus .Chenopodium vu/varia ••..•...•..•..••..

fff#!§§:j··:.:.:·::: ..•::.:.::::::

Thble 4.

204 CANDOLLEA 50. 1995J. L. CARRETERO _ SUMMER AGRESTAL VEGETATION OF DRYLAND CROPS IN SPAIN 205

Thble 5 (continuation)

A, n:5Q Ab n: 50 B n: 50 C n: 100 D n:50

Polygonum belJerdii • .. 2 2.50 0.05 6 1.17 0.07 4 0.50 0.02 6 1.50 0.09 2 0.50 0.01Amaranthus viridis . ... - - - 6 1.83 D.lI 2 2.50 0.05 9 3.67 0.33 2 2.50 0.05Conyza canadensis . _•. 10 1.70 0.17 4 1.50 0.06 - - - 3 •.00 0.18 2 0.50 O.QlEquisetum ramG-

sissimum .•.. .••.. _. - - - 4 2.50 0.10 - - - 5 4.10 0.20 8 2.00 0.16Chrysanthemum coro-

narium ..•....•.•.. - - - 10 2.10 0.21 6 2.50 0.15 - - - - - -Cichorium intybus •.•. 2 2.50 0.05 - - - 6 Ll7 0.Q7 6 1.17 0,07 2 2.50 0.05Rumex buccphalophorus 6 1.83 0.11 6 6.00 0.36 4 LSD 0.06 - - - - - -Anacyclus radia/us •.•. - - - 10 1.70 0.17 4 1.50 0.06 - - - - - -Beta maritima • .••.••. - - - - - - 4 1.50 0.06 7 2.21 0.15 2 2.50 0.05Chrysanthemum

segctum 6 I.l7 0.07 4 150 0.06 2 2.50 0.05 - - - - - -

The bioc1imatic terminology used follows the criteria of RIVAS-MARTINEZ (1987a). Forsoil analysis (Table 6), the official methods, approved by the Spanish Ministry ofAgriculture, Fish­ing and Food (VALLEJO, 1986), were followed for pH, texture, total and active calcium car­bonate, organic matter (O.M.), total nitrogen (N) and salinity expressed in conductivity of thesaturation extract (Sat. ext. conduct.) and in sodium adsorption relation (SAR) of the saturationextract. Inorganic nitrogen (Inorg. N: nitrates, nitrites and ammonium) as well as sulphates(S04=) were extracted and later analysed by colorimetry (WALTERS, 1989).

The taxa names are given according to CASTROVIEJO & a1. (1986-1993), GREUTER& al.(1984-1989) or TUTIN & al. (1964-1980), except Conyza sumatrensis (Retz.) E. Walker (C. albidaWilld. ex Spreng.). For the syntaxa we have followed the rules of the Code of PhytosociologicaJNomenclature (BARKMAN & aI., 1986).

Description oj the communities

Eragrostio majoris-Chenopodietum botryos Br.-Bl. in Br.-Bl. & aI. 1936.

Our releves could be assigned to three syntaxa: Eragrostio majoris-Chenopodietum botryos(BRAUN-BLANQUET & al., 1936, 1952), Tribulo terrestris-Heliotropietum europaei (RIVASGODAY, 1956) and Heliotropio europaei-Amaranthetum albi (RIVAS GODAY, 1964). After theanalysis of the phytosociological tables presented by the aforementioned authors, it seems imposi­ble to consider these associations as different, as is indicated by POLl (1966) and BRULLO &MARCENO (1980) in some measure. Although the first name is somewhat unfortunate, it is theone that should prevail according to the Phytosociological Nomenclature Code (BARKMAN &al., 1986). Given that BRAUN-BLANQUET (BRAUN-BLANQUET & aI., 1936) bases hi.description on a presence synthetic table without indicating type releve, reI. 7 (Table 1) is proposedas neotype, considering that it is a perfect representation of the Eragrostio majoris­Chenopodietum botryos meaning.

It is characterized (Tables 1and 5) by a great presence ofAmaranthusalbusand Heliotropiumeuropaeum, frequently accompanied by other Diplotaxion (Tribulus terrestris, Salsola ka/i,Chenopodium botrys, etc.) and Panko-Setarion (Amaranthus retrof/exus, Salanum nigrum, Por­tulaca oleracea, etc.) taxa. There is also a high incidence of a more general ecology species suchas Chenopodium album, Convolvufus arvensis, Chondril/a juncea, Cynodon daetylon, CirsiumarvenseJ Chenopodium vulvaria and Xanthium spinosum, among many others.

In the warmer regions, more thermophilous elements occur, especially Amaranthus b/itoides,which make it possible to differentiate a subassociation: amaranthetosum b/itoi'dis (Table I, relevesIQ-18, holotype: rel. 11), which is proposed as new. The presence of Chrozophora tincloria in the

warmest summer areas permits the identification of a variant ofan even more thermic nature. Theyrepresent a transit towards the Chenopodio albi-Amaranthetum blitoidis and Kickxio lanigerae­Chrozophorelum tinetoriae, respectively.

Overall cover tends to be low, rarely exceeding 500/0. The most important species (Table 5),with highest frequency and cover percentages, is Amaranthus albus. Then follow Chenopodiumalbum, Reliotropium eurOpaeum, Convolvulus arvensis, Chondri//ajuncea and Cynodon daety~Ion, among many others, but with much lower values. Amaranthus b/itoides is of great relevancewithin the Amaranthetosum b/itoidis subassociation.

This association is distributed through Mediterranean Spain (Fig. 2), being scarcer in theeastern regions. The greatest representation of the typical subassociation is found on the NorthernMeseta and the Central and Iberian mountain systems, which have a Supramediterranean ther­moc1imate. Amaranthetosum b/itoidis subassociation occurs in the Thermo and Mesomediterra­nean biodimatic stages.

Both subassociations grow in dryland fields (vines, sunflowers, fallow lands, etc.) as well asin irrigated crops (melons, watermelons, sugar beets, etc.) with low soil moisture. In the soil sam~pIes analyzed (Table 6), coarse particles are predominant, pH is acid or slightlY basic and the cal­cium carbonate percentage nil or low. Organic matter. nitrogen, sulphates and salinity tend to beof low proportions.

Kickxio lanigerae-Chrozophoretum tinctoriae Rivas Goday ex Izco 1975.

This association was perfectly studied by IZCO (1975) in Central Spain. It is characterized(Tables 2 and 5) by the almost constant presence of Chrozophora tinetoria, accompanied or sub­stituted on rare occasions by Kiekxia lanigera andlor Chrozophora obliqua, together with otherDiplolaxion therophytes (fundamentally Beliotropium europaeum, Amaranthus albus andAmaranthus blitoides). Some Ruderali~Secalietea therophytes (Chenopodium album, Chenopo­dium vulvaria, Xanthium spinosum, etc.) and geophytes (Convolvulus arvensfs, Cynodon dacty­Ion and Cirsium arvense) are also frequent.

In the 50 releves carried out, all within the crops, no appreciable variability was found, noneof them corresponded to the sonehetosum crassijo/iae and kickxielosum spuriae subassociationsindicated by IZCO (1975).

Overall cover in cultivated fields tends to be rather low, similar to that corresponding to theEragrostio-Chenopodietum botryos. The species with highest frequency and cover percentages(Table 5) is Chrozophora tinctoria. Heliotropium europaeum, Chenopodium album, Amaranthusalbus, Convolvulus arvensis and Amaranthus bliloides follow with a certain importance. Othertaxa are Cynodon daclylon, Chenopodium vulvaria, Cirsium arvense, Xanlhium spinosum, Kick­xia lanigera, Lactuca serriola, etC.

The association is distributed (Fig. 3) in the areas with the highest summer temperatures(Southern Meseta, Guadiana extremaduran Basin, Western Andalucia and the Ebro Depression,radiating towards the SE of the Iberian Peninsula), where a Thermo to Mesomediterranean ther­moclimate is found.

It grows in dryland fields (vines, sunflowers, legumes, almonds, fallow lands, etc.) and inirrigated crops (sugar beets, melons, watermelons, etc.) with low soil humidity. In the soil samplesanalised (Table 6), the texture varies from sandy loamy to clayey and the pH ranges from practicallyneutral to relatively high. Calcium carbonate content oscillates from low to high. Organic matterand nitrogen tend to be in low proportions. Sulphate concentration and salinity show values frombetween nil or very low to moderately high. IZCO (1975) indicates very gypseous and very salinesoils in some of his releves.

Tex/UfI! Sand % pH To/al Aetive 0.'\'1.% Thtal lnorg. SO~~ Sat. ext. SARCO;Ca% CO;Ca% N.% N. pp!1l. ppm eondue/.

A, sand to sandy loam 60.50-88.15 5.80-7.95 0.00-25.68 0.00-2.30 0.17-1.93 O.OI..{l.lO 3.25-15.00 0-1500 0.30--2.05 0.15-0.80n: 10 76.18 6.85 SAl 0045 058 0.D3 8.92 205 0.75 0.34

Ab sand to sandy clay loam 50.50-96.00 6.70-8,25 0.00-28.10 0.00-4.20 0.15·2,]2 0.0I..{l.l4 5.25·21.25 0-1600 0.58-1.63 0.26-L70n: 10 70.33 7.83 6.85 1.05 0.88 0.05 13.20 210 Ll2 0.88

B sandy loam to clay 30.80--78.40 7.25-8.30 OJXl-42.68 0.00-5.55 0.20-2.44 0.01-0.15 7.40·17.50 0-5500 0.54-3.66 0.25-2.65n:1O 58.61 7.78 8.92 1.26 1.02 0.07 11.32 650 1.37 1.04

C sand to clay 10.55-93.65 7.27-8.90 0.00-75.45 0.00-18.50 0,]5-6.56 0.01..{l.21 6.35-45.50 0-7000 0.38·12.35 0.25-15.26n: 25 56.64 8.27 29.75 7.55 1.27 0.07 17.20 1200 1.85 1.65

D sandy loam to clay 9.05-74.34 8.00-8.75 9.20·59,52 1.10·10.65 0.15-3.04 0.01·0.19 6.25-32.50 0-4000 0.49-2,83 0.32-6.96n: 11 43.30 8.38 27,80 4.97 1.45 0.10 15.96 550 1.16 1.37

Table 6. - Extreme and mean values of major physlcal.chemical factors of soils (see e.xplanations in the te.xt). Aa: Erogrostio-Chenopodietum bo/ryos ehenopodie/osltl1lbo/ryos; Ab: Erogroslia-Chenopodie/um bo/ryosa!1loronthelosum b!i/ofdis;B: Kickxlo-Chrot,Ophofl!tum rinctoriae; C: Chenopod/o-Amaronthetum Mitoidis; D: Amarantho·

Diplotux/efum entcoidis; n: numbl:r of samples.

t.;

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'-~.....-.~ .. * .: """; :::~ ......' •.,.. ",' ., .., :**' . ~ ''''-t.'. "~ ..

/'>\~ '<\ :/' ~?~.",:~»:;·2,:--.,,",:;,,}* ~. *..' ~; .. ,."; "':-"~' .....' -"L" ":,:....:r,,'''''r "\,,; (,:., ....\/o'-<.~

"'~";""~", * :*it .< :_..... • *(*:..... -;... :..~ * * 1c.\~ ..: :·•.}.:~it -' .. ;\.-.. I \. r~ *' =:.~ .. '• ..,

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208CANDOLLEA SO, 1995

-,, .

, ," I I •

,l"\~":"':'~r:,.><J·'1 "~"". _.1. .. • ,, ',....."".. . ':. .. . ..~.. . ,/.. :,''. , e} "" :' .- ..... ..-...'... ~)• , \ ,I" .... ~("... /'.~, ) : /~ :, '_,".' • ,'_ \ I

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Fig, 3. - Distribution of the studied localities of Kickxio lanigerae-ChrozOPhoretum tincforioe.

J. L. CARRETERO - SUMMER AGRESTAL VEGETATION OF DRYLAND CROPS IN SPAIN 209

Chenopodio albi-Amaranthetum blitoidis assoc. noy.

It is characterized (Tables 3 and 5) by the almost constancy of Amaranthus bIitoides and thenotable presence of other annual taxa belonging to Diplotaxion (Salsola kali, Diplotaxiserucoidesand Heliotropium europaeum, among others) and to Panico-Setarion (Amaranthus retroflexusand Portulaca oleracea). Species of Ruderali~Secalietea (Chenopodium album, Convolvulusarvensis, Chondrillajuncea, Cirsium arvense, Cynodon dactylon, Xa'nthium spinosum, etc.) arealso frequent. Holotype: reL 12, Table 3.

The surface covered by the association is variable, the higher cover being frequent, greaterthan 600/0. The most important taxa, with highest frequency and global cover percentage, are(Table 5): Amaranthus blitoides, Salsola kali, Chenopodium a/bum, Convolvulus arvensis,Amaranthus retroflexus, Cirsium arvense, Cynodon dactylon, Dip/otaxis erucoisdes and Chon­dril/a juncea, among many others.

In spite of being a relatively homogeneous association (a division into subassociations wouldnot seem to be convenient) as one could consider some variants according to the variation ofenvironmental factors. As, for instance, the presence of Chrozophora tinctoria as a transit to theKickxio lanigerae-Chrozophoretum tinctoriaein the hottest summer regions, Panico-Setarion spe­cies in more humid soils and halophytes such as Beta maritima in saline soils.

It is relatively similar to the association Atriplici rosae-Salsoletum ruthenicae (RIVAS~

MARTfNEZ, 1978)ofthealliance Chenopodion muralis. The existanceoftaxa which are commonto both associations, especially Sa/sola kali and Amaranthus blitoides, have lead to the fact thatreleves carried out until now on the Chenopodio albi-Amaranthetum blitoidis have been includedin the A triplicirosae~Salso/etum ruthenicae (ALCARAZ, 1984; ALCOBER, 1983). In our associa­tion, of agrestal and no ruderal character, as well as the great dominance of Amaranthus blitoides,a lower frequency of Sa/sola kali and an almost complete absence of Atrip/ex rosea, it gatherstogether a rich variety of predominantly agrestal taxa. Moreover, Chenopodio a/bi­Amaranthetum bli10idis does not spread into the Supramediterranean bioclimatic stage, asopposed to Atriplici rosae-Salsoletum ruthenicae, which is quite at home there (LADERO & al.,1983; BURGAZ & SAIZ, 1989).

Our association reaches its optimum development (Fig. 4) in the eastern half of Spain (veryprobably including the Balearic Islands), radiating towards the SW of the Iberian Peninsula, whereEragrostio majoris-Chenopodietum botryos amaranthetosum b/itoidis and Kickxio lanigerae­Chrozophoretum tinctoriae predominate. It grows on the Thermo and Mesomediterranean biocli­matic stages.

It occurs chiefly among dryland crops (almonds, vines, olives, sunflowers, etc.), and can alsobe found on irrigated land with low soil moisture. In the soil samples analysed (Table 6) textureranges from sandy to clayey and pH varies from between almost neutral to highly alkaline. Limecontent tends to be high, although in some cases it is nil. The proportion of organic matter andnitrogen are variable. but soils are predominantly poor in these elements. Sulphates and salinityoscillate between nil or low quantitites to quite high ones, as happened with the samples takenin the SE of the Iberian Peninsula.

Amarantho delilei-Diplotaxietum erucoidis Br.-El. ex Br.-Bl. in Br.~Bl. & al. 1936 nom. inv.

The association described by BRAUN-BLANQUET (BRAUN-BLANQUET & aI., 1936) isa mixture of winter~springand summer-autumn species. Although the original diagnosis cor­responds to a synthetic table with no individual releves, we consider that the vegetation we havestudied corresponds to this association, reserving the Winter-spring taxa for other communities.Releve 1 (Table 4) is put forward as the neotype, being the closest, of those available, to the regionwhere the association was originally described.

It is characterized (Tables 4 and 5) by the abundance and almost constant presence ofDiplotaxis erucoides, sometimes accompanied, or on rare occasions substituted, by Erucastrumnasturtiifolium, together with summer-autumn species of So/ano nigri-Po/ygonetalia convolvuli

210CANDOLLEA 50. 1995 J. L. CARRETERO - SUMMER AGRESTAL VEGETATION OF DRYLAND CROPS IN SPAIN 211

Fig. 4. - Distribution of the studied localities localities of Chenopodio albi-Amaranthetum blitoidis.

(Amaranthus retroflexus, Portulaca oleracea, Amaranthus blitaides, Setaria v/rid/s, Sorghumhalepense, etc.). The Ruderali-Seca/ie/eataxa are also frequent, such as Chenopodium album, Con­volvulus arvensis. efrsiurn arvense and Chondrilla juncea, among many others.

In the biotopes where the association reaches maximum development, generally in spaciouslyplanted woody crops, cover is high, easily passing 60070. Diplotoxis erucoides is the species withby far the highest global cover percentage (Table 5). Followed, with much smaller values, by Cirsiumarvense, Convolvulus arvensis, Chenopodium album, Erucastrum nasturtiifolium, Amaranthusblitoides, Chondri//ajuncea, Amaranthus retrof/exus, Cynodon dactylon, Setaria viridis, Sorghumhalepense, etc.

This association is distributed (Fig. 5) throughout· the eastern half of Spain, including theBalearic Islands, being most abundant in areas with the highest summer rainfall (NE of the IberianPeninsula). Bioclimatically, it presents a wide ccalogical spectrum. establishing itselfin the Therma,Mesa and Supramediterranean stages. In the warmer (Thermo and Mesomediterranean biocli­mates) and less humid biotopes, Amaranthus blitaides appears as a differential species, permitingthe identification of a subassociatian: amaranthelosum blitoidis which is proposed as new (Table4, releves 9-16, holotype: reI. 14), establishing the transit towards the Chenopodio albi­Amaranthetum blitoidis.

The association grows principally among dryland woody crops (almonds, vines, olives, etc.),although it is also frequent among herbaceous ones. In dryland areas, soil humidity correspondsto that found in a subhumid or not particularly dry ombroclimate. In more arid regions a moderateirrigation is necessary for its development.

In the samples analysed (Table 6) the soils that predominated were those with a higher propor­tion of fine particles, although some of them proved to be of a sandy loamy texture. Calcium car­bonate content and pH tend to be quite high. Organic matter and nitrogen, the total as much asthe inorganic, are variable, depending on whether the sample was taken from dry or irrigated land.This association can establish itself, perfectly well, in gypseous and saline soils, as in the case ofthe releve 16 (Thble 4) from Villena (Alicante).

Conclusions

This paper describes the summer-autumn vegetation found in 300 dryland or scantily irrigatedcultivated fields (Diplotaxion erucoidis alliance) of the Spanish Mediterranean region, excludingBalearic Islands. This type of vegetation falls within the following syntaxa:

Ruderali-Secalietea cerealis Br.~Bl. in Br.-Bl., Gajewski, Wraber & Walas 1936 (Syn. Steflarieteamediae R. 'IX., Loh'meyer & Presing in R. Tx. 1950.lncL Secalietea Br.-BL in Br.-Bl., Roussine& Negre 1952; Chenopodietea Br.~BL in Br.~BI., Roussine & Negre 1952).Chenopodietalia albi R. "IX. & Lohmeyer in R. Th. 1950 [Syn. Solano nigri-Polygonetalia con­

volvuli (Sissingh in Westhoff, Dijk & Passchier 1946) O. Bolos 1962; Chenopodietaliamuralis Br.-Bl. ex Br.-Bl. in Br.-Bl., Gajewski, Wraber & Walas 1936 p.p. Incl. Polygonoconvolvuli-Chenopodietalia albi J. Tx. in Lohmeyer & al. 1962; Eragrostietalia J. 'IX. inLohmeyer & al. 1962].Diplotaxion erucoidis Br.-Bl. ex Br.-Bt. in Br.-Bl., Gajewski, Wraber & Walas 1936 (Syn.

Eragrostion R. Th. in SIavnic 1944 p.p.).• Eragrostio majoris-Chenopodietum botryos Br.-Bl. in Br.-Bt. Gajewski,

Wraber & Walas 1936 (Syn. Tribulo terrestris-Heliotropietum europaei RivasGoday 1956; Panico sanguinalis-Eragrostietum barrelieri Rivas Goday 1956corn. prov. p.p.; Heliotropio europaei~Amaranthetumalbi Rivas-Goday 1964prov. p.p.). Preferably silicicoious.

chenopodietosum botryos. Mainly Supramediterranean.amaranthetosum blitoidis subassoc. novo Thermo-Mesomediterranean.

212 CANDOLLEA 50, 1995 J. L. CARRETERO - SUMMER AGRESTAL VEGETATION OF ORYLAND CROPS IN SPAIN 213

;( - ,(..{ )~ ,,- - v" -~'n·;·-o~:,.:7:~>t-'.... !')~'.'.;,?;l'~ ~:' ':t.,' ....~ . ~',,- ..- ,. ~.. '., "- ."~, ;:. I ... ,.

/_',_';-:Y<{::},~~:::)r<':'..: ;,n ,j._'}j.': 'ic:'''''-

:5'" ,.,,)-',..... \~:<';;~::• ". ! ' •• -¥:

~/'·(\,':':··i>~····· .

J.. • .-,: • I

';." ~.':. ..,

Fig. 5. - Distribution of the studied localities of Amarantho deJilei-Diplotaxietum .erucoidis: • dipfotaxietosum crucoidis;- "f( amaranlhelasum blitoidis.

F PC GC

Amaranthus bili/aides ...... 57.67 14.82 8.55Amaranthus afbus .. 49.33 10.28 5.07Dip/o/axis erucoides ......•. 29.67 13.26 3.93Chenopodium album. 66.67 5.68 3.79Convolvulus urvensis • •...••• 51.67 5.48 2.83HeIiotropium europaeum . 37.67 5.42 2.04Sa/sola kali . .. . ...•. 23.67 8.11 1.92Chrozophora tinctoria . .... 20.33 8.61 1.75Cirsium arvense ...•. 28.33 5.58 1.58Cynodon dacty/on ••...•.... 29.00 4.52 1.31Amaranthus relroflexus.. 25.67 4.25 LOOChondrilla juncea . 34.00 2.78 0.94Chenopodium vulvaria . 19.00 '.84 0.87Tribu/us terreslris .. ...•..•.. 16.00 3.56 0.57Portulaca oIeracxea ...•..••. 20.67 2.76 0.57Xanthium spinosum .•.... 20.33 2.56 0.52Erucaslrum nasturlii/olium •. 6.67 7.65 0.51Setaria viridis ...•••••.•.••• 11.33 3.97 0.45Sorghum halepense ....•..•• 8.67 5.07 0.44Sonchus oleraceus .....••.•. 16.67 2.52 0.42Solanum nigrum ..•....... 12.67 2.53 0.32Cyperus rotundus........ 9.67 3.10 030Eragrostis barre/icri . 11.00 2.73 0.30Lactuco serriola ..•••••••... 10.00 2.70 0.27£olium rigidum ... " ...... 9.67 2.58 0.25

Thble 7. - Frcnquencies (F). and partial (PC) and global (GC) cover percentages (sce cxplanations in the tcxt) of the 25 mostharmful weeds in the whole of the 300 releves.

Kickxio /anigerae-Chrozophoretum tinctoriae Rivas Goday ex Izco 1975 (Syn.Heliotropio europaei-Amaranthetum albi chrozophoretosum tinctoriae RivasGoday 1964 prov.; Chrozophora tinctoriae-Heliotropietum europaei RivasGoday 1964 nom. nud.). Thermo-Mesomediterranean. Hottest summerregions. Indifferent to soil types.

• Chenopodio albi-Amaranthetum bliloidis assoc. novo (Syn. Atriplici rosae­Salsoletum ruthenicae auct., non Rivas-Martinez 1978). Thermo~

Mesomediteraanean. Preferably Iberian-Levantine. Mainly calcicolous.Amarantho delilei-Diplotaxietum erueoidis Br.-Bl. ex Br.-Br. in Br.-Bl.,Gajewski, Wraber & Walas 1936 nom. inv. (Syn. Diplotaxietum erueoidis Br.­BL in Br.-Bl., Gajewski, Wraber & Walas 1936 prosyn.; Erueastro nasturtiifolii­Diplotaxietum erueoidis Brullo & Marceno 1980). Iberian-Levantine. Cal­cicolous.

diplotaxietosum erueoidis. Thermo to Supramediterranean. Lessxerophile.amaranthetosum blitoidis subassoc. nov. Thermo-Mesomediterranean.More xerophile.

The most phytosociologically significant species of the spanish Diplotaxion agrestal communi­ties are (Table 5): Amaranthus albus, Amaranthus blitoides, Chrozophora tinetoria and Diplotaxiserueoides. Other alliance characteristic taxa are: Heliotropium europaeum, Sa/sola kali, Tribulusterrestr~ Setaria virid~ Eragrostis barrelieri, Sorghum halepense, Chenopodium botrys, Erucas­trum nasturtiifolium, Xanthium orientale, etc.

In all the studied communities some species of Panieo~Setarionare frequent (AmaranthusretrojIexus, Portulaea oleracea and Solanum nigrum being the most important) and there is a highincidence of the agrestal taxa of a more general ecological character, belonging to Ruderali­Seealielea, such as Chenopodium album, Convolvulus arvensis, Chondrilla juncea, Cynodon dae­tylon, Cirsiumarvense, Chenopodium vulvaria, Xanthiumspinosum. Sonchus oleraeeusand manyothers.

214 CANDOLLEA 50, 1995 J. L. CARRETERO ~ SUMMER AGRESTAL VEGETATION OF DRYLAND CROPS IN SPAIN 215

FIoristically, a total of 180 taxa was recorded, considering that the floristic diversity of summer~autumn agrestal vegetation is much lower than that of winter-spring one. Considering only the 63most important taxa shown in Table 5, the families with the highest number ofspecies were Compos_flae (220/0), Gramineae (170/0), Amaranthaceae (110/0) and Chenopodiaceae (10070); 840/0 of theweeds were therophytes, 11% geophytes and 50/0 hemicryptophytes; asignificant number (170/0) wereof American origin, e.g. Amaranthus a/bus, A. blitoides, A. retroflexus and Xanthium spinosum.

The 25 most aggressive weeds surveyed in the whole of the 300 releves without grouping incommunities (Table 7) were Amaranthus b/itoides, A. a/bus, Dip/a/axis erucoides. Chenopodiumalbum, Convolvulus arvensis. Heliotropium europaeum, Salsola kali, etc.

Chenopodium album. Convo/vulusarvensis. Cirsium arvense. Cynodon dactylon. Chondri/lajuncea and Chenopodium vulvaria. among others, are species with a broad ecological and sociolog~

ical amplitude, forming a high percentage of the weed floras of all the communities (Table 5) andtherefore they are very widely distributed in all the studied territory. Amaranthus retroflexus, Por­lulaca oleracea and Solanum nigrum are summer weeds characteristic of irrigated fields, but theypenetrate into dryland crops where soil retains a certain humidity.

Amaranthusalbusand Heliotropium europaeum shown a certain preference for siliceous soils,being much more frequent and abundant in the Eragrostio majoris-Chenopodietum botryos andKickxio lanigerae~Chrozophoretumtinctoriae associations, that is to say in the western half of theSpanish mediterranean region and in some localities for the rest of the Mediterranean Spain.Amaranthus blitoides occurs only on the Thermo and Mesomediterranean bioclimatic stages andit is indifferent to soil types; it is one of the most important weeds of all the surveyed territory,except of the Supramediterranean Eragrostio-Chenopodietum botryos chenopodietosum botryossubassociation (Northern Meseta, Central and Iberian mountain systems, as principal areas) andof the Supramediterranean zones of the Amarantho delilei-Diplotaxietum erucoidis association(prepyrenean regions and upper Eastern Iberian mountains).

Diplotaxiserucoidesis a weed commonly occurring on calcareous soils with a moderate humid­ity; it is distributed mainly throughout the eastern halfofSpain, being most abundant in thehighestsummer rainfall areas, e.g. NE of the Iberian Peninsula. Chrozophora tinctoria is distributed inthe highest summer temperature areas (Southern Meseta, Guadiana Extrernaduran Basin, WesternAndalucia and the Ebro Depression), where a Thermo-Mesomediterranean bioclimate is found.Salsola kali prefers xeric habitats; that is why it is much less frequent in the Amarantho delilei­Diplotaxietum erucoidisassociation, where the soil moisture is slightly higher than in othercommu­nities.

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