Irrigation systems and techniques for saline water

Transcription

1 Irrigtion systems nd techniques for sline wter Cvzz L. in Bouchet R. (ed.). Reuse low qulity wter for irrigtion Bri : CIHEAM Options Méditerrnéennes : Série A. Séminires Méditerrnéens; n pges Article vilble on line / Article dponible en ligne à l dresse : To cite th rticle / Pour citer cet rticle Cvzz L. Irrigtion systems nd techniques for sline wter. In : Bouchet R. (ed.). Reuse low qulity wter for irrigtion. Bri : CIHEAM, p (Options Méditerrnéennes : Série A. Séminires Méditerrnéens; n. 1)

2 CIHEAM - Options Mediterrneennes Irrigtion systems nd techniques for slinewter CAVAZZA University Bologn - Itly ll regions tht suffer, if only sesonlly, from illustrtes evolving contrsts in rush insufficient rinfll, griculturlts hve lwys extend use sline wter in irrigtion. sought find dditionl wter for irrigtion. Tody se efforts re incresing due problems incresed popultion, tendency wrd more efficient lbour nd higher stndrds living. They re fvoured vilbility cpitl, - requirements progress in griculturl techniques, s well s well known tht min in using mrket expnsion nd orgniztion. Under se conditions wter t higher cost nd lower excessive slt levels in soil must qulity thn ws ccepted in pst now being used in dry res, while in rinfed res irrigtion given lso being extended crops tht trditionlly hve been coidered in need irrigtion. developed As whole, in semi-rid conditions, shift from dry frming irrigtion with brckh wter hs led increses in yield nd prit. These nd mny decdes scientts hve still being dvntges, however, re lower more sline wter. Th implies tht mximum level concept well known both in its second wter slinity ctully lerted in prcticl irrigtion increses with ridity, mngement Lb.; see et l., skill frmers nd with mrket vlue : product; it decreses with ring living stndrds. For exmple, yers go cnning mes irrigted with brckh wter nd hnd hrvested were n importnt crop in some res sourn low yield. sme wter now used for more vluble crops (minly utumn--spring vegetble crops, or cpsicum, eggplnt, rtichoke, grpes, etc.). possible tht if mrket becomes unfvourble for se vluble crops, re irrigted with brckh wter will contrct nd highest cceptble slinity for prcticl irrigtion will drop. Th = E = &/ E c~ = E = = sme zone; nd = soluble slt contents. Serie A: Seminires mediterrneens

3 CIHEAM - Options Mediterrneennes The second : but = E E,, - E,W), it : complicted when s well s some ccount. - methods = Ecw / 2- E,, = soil pste nd Ece~ = Ece 100% yield loss. The suitbility use flooding cm well known. Continuous fields s well s might be FAO, stedy stte zone soil slinity No. not so s in slts leched out following seson (mostly in conditions hs not been sufficiently developed. The old slinity could tke in simple wy: = (Ecr. V, + Ecw.VW) (Vr + et l., 1967) not cse with new E,,. now mostly When bsin method slinized soils (th method low conditions hs especilly (Figure 1). One plced in such wy bove level mny decdes, so tht zone letting slt ccumulte on one edge et l., 1976); closed t botm, such s slt ccumultion t soil liquid flow in still o in common o soil-plnt system. As do not effect Tble 1 Lunin et l., lech out soil slts become conditions plnt could voids ppliction nd plnts, i.e., depth Serie A: Seminires mediterrneens

4 CIHEAM - Options Mediterrneennes smll depth single ppliction. wy (Figure 2; 1975). ppliction tht slt tends ccumulte t soilwell known zone et l.,' 1973). (e.g. th t not likely zone. mix up soil nd, nywy, it not esy soil. should be - Wter sources nd irrigtion methods choice ) t slightly fluctuting slinity; b) c) usully communictes with se nd its sttics Ghyben- (Childs, 1969; Cvzz, 1981). A (i.e. two shllow soil (1 m deep) tht mesozoic limesne nd slt on On bses its exceed se level thickness equl Ah = (ps - pf) /pf pf nd ps 1/40; in 1964). flow climtes) 1955; Cotechi, 1955; on level cost. On (e.g. 3). well, tble, floting blnce Ah = 1/30 flow (see Figure on slt will tend obvious well below se level tfie well will below cone slt will become. se cses, most Of min choice system which slt leching, good (if nnul) nd well 1968). A typicl beginning end ll, its slinity 1.5 2%0) t cycle). double t well low only when level Serie A: Seminires mediterrneens

5 CIHEAM - Options Mediterrneennes smll. The well, hence condition ws once obtined wheels s slowly depths, zone. it methods used now use well s cost slinity th type ten not o high; it might be comes wns, due possible Technicins chepest if one, helth be t lso used in whole mount volumes, inside which most Th usully multiplies effects se on soil t clogging (exmples shown in Figure 4). th type effluent (Sposi et l., 1978; et l., 1981; et l., 1983). Usully th implies effective djusted s computed one. Let us go bck ccumultion in - Or technicl spects soil. vlues) t not o keep shllow, luminium sesquioxides (minly lfols), good pplied chiefly sme soil so s slts soil, ws between those Only with 2%0 it possible ppliction (bout 250 t pek soil, its so tht continuous slow zone. in s usully smll 3,000-4,500 m3h. usully kept need be common not beneficil stfy whole s it its = ETC - ETo X becuse n excessive low (low content, delyed shipping cpcity). Usully only bout 2/3 whole spect. Th tht two while only choose between Serie A: Seminires mediterrneens

6 CIHEAM - Options Mediterrneennes one cused soil comes help. No now questionble. its nonlimiting mount constnt, limited flow lso in choosing between use s whole The hs single cses tking in ccount s sensitive use economicl spects should lso be tken in ccount. some situtions low nd it n suitble stges, when mount such type mostly in could condition mixed in ) yield s function b) flow; c) cost both volume; ppliction, e) ech hs be put in wy. not flow th seson. The solutions dely in use it in pek pplied shifting t sline mixed) cnopy with The functions () wy s be (y = const.) in given n techniques suitble. th.e line slope mximum yield one, two cost sline one, volume effects, both positive nd negtive, on conditions plnt, while (Cvzz, 1968). constency, held beliefs on tested, i.e. blossom 1937). becomes Serie A: Seminires mediterrneens

7 CIHEAM - Options Mediterrneennes A., Y The use gel bound C nd in sewge ffluent-soil systems. Shuvl in zone ecology Ficco, N., Un Genio 24,pp con Lunin, J., Glltin, C.A. nd L.V. Wilcox, Use Exp.: USA., No nd Wescot, FAO, No. 29. L. nd L.E Leching studies: Sensitivity lflf slinity Sci. Soc. 37, pp V Soil conductivity s ffected physicl No. 3, pp E., con Stzione 26,72 p. E., Two-dimensionl pp Soil Sci. Soc. Am. nd Slt T.W.. USA: pp Cvzz, L., The Ed. W. Junk N.V. pp Cvzz, L., UTET. Cotecchi, in zone con d'cqu Geotechnic, 2,105 p. Childs, E.C., An th physicl bs soil London: John Wiley.S Some on use FA0,Stenciled Sposi, nd C.S. Lvesque Soil Sci. Soc. Am. J., No. 42, pp. nd Co. E. Y. Vdi, London: Ecologic. Studies, No. L. nd C dell slinit delle cque del Scienz e Technic No. 4, pp options méditerrnéennes Serie A: Seminires mediterrneens

8 CIHEAM - Options Mediterrneennes 55 Tble Permsible number irrigtions with brckh wter between leching rins for crops different slt lernce Irrigtion wter Irrigtions for crops hving slts Totl Electricl conductivity Good slt Moderte slt Poorslt lernce lernce lernce Prts per million MiIliSiemens, Number Number Number centimeter l '. 11 Source: Lunin et l., options Serie A: Seminires mediterrneens

9 CIHEAM - Options Mediterrneennes et l., et l., = slt For 2: in (meq/dm3 bulk soil volume). From (%? 20 cm I options Serie A: Seminires mediterrneens

10 I CIHEAM - Options Mediterrneennes 3: well sliniztion cused 4: Accumultion in time N nd (?: unpublhed dt lso evident m P l i... ; options Serie A: Seminires mediterrneens