PRACTICAL IRRIGATION

Otago Daily Times, Issue 15350, 13 January 1912, Page 5

PRACTICAL IRRIGATION

rLVNT i.iri;. iiy John M'Kkaoii:. I. ((.'op.VlTjht ) In order to iin-lcisiaml iho cltects oi iirii,'.ition in the roil ami on the life and growth of plants it i;-. nices.-ary lir.-t l<i understand lioiv plaiil.-. uerininate. live, grow, and ie|iioiii!cc thomsidves; and. iiirUii.t. what fresh conditions and cfiirl. ar--pri'diKvd in tin: soil by tlu prcif.-nc.- of irrigating water. «iiiii: plums. a» the iiiistleloi, live and grow in air only; oiher.s in water only, lint th.. soil is the 1/irtli place and ihc Ikmiio of nearly all plains and from the mil and the air all plant life demi'h its daily food, ttiiiie plant, aie reorcdiieit! from .'iittinr-, i-iit n<*'• '"'■'•' plant life i.s deriv.d from >.'-'d-. I'i-inU and ii.'iihi arn M.i'.ariited into varii-.u.' clan's but for our parj.-ise, v.nicli i» m in.-.lei'-coiiilitions neecs-iK f»r the growth, the tlevelupinent, .-U..-I ihe reprodiiciiou of plant, it i- n.:e.'s,iiy only lo uniler.-land the fuci." in relation to two (ommon seeds --the o-a. ull.i Ihe seed of wheal. Take a l>oa ai.tl carefully examine it. Around tlio outside is a skin of dead matter. Ueinovc the -.kin. and the remaining part will bfound to coiis!.-.| of two thick inti.-.<es piano face I'i fuio; and, further. I In so two thick ma-.es are united by ;i loug-;'hajK-d Isxly, which is jfiinifl |i> each mass. This long tlinped !/xly is Ihe embryo, and the ihicl; )ii,'ese:s furnish food [tir the germinated and growing young plant. Kxatnino now th.i H»."d of wheal. The otuhryo here '.insists of one thick mass, which is placed at one side; the other side oin-i'ls of a while lloury -ulislame. Take either of those reeds and place li in dry mould. Ho long us ihe mould remains dry the se:'d will not germinate Moi-ten the mould, hut keep 1 hi; «eed and the mould at or Mow the freo7.iuK'poiiil. and iho seed will-not gM'rniili'.dc. Xow place ihe seed in moist mould ami in a temperature above the freezing|minl, but exclude the air, and still tit' seed will not germinate- Hut if the air !m allowed lo come in contact with lie" <i'i'd and to circulate ihrough tlm moist. warm mould, the wed will germinate. Large ipianlitioH of oxygen, which is one of the gave that form the air. arc consumed by germinating .-e.-ds, and will not germinal:! in the absence of oxygen, and hence Ihe air must liud its way freely lo tlie eoruiinaling need." The «iinbination of oxygen with other elements is termed oxidation It, thus appears, that three conditions arn neep.»iary for the germination of r-M'il—(a) moisture, (M warmth, h) air. When the Med commences to grow one end of the !ong-sh.-i.|>od Imdy grows upwards and fornv.i the wlem, and afterwards Ihe branches, loaves, buds, and Honors of the new plant. The other end grows downwards and forms tlio root. In many c'lfvs the root descends to a (,'iciit depth in iho soil, aiul is known as the taoroot, as in the case of the pea an.! other plant, of the name family. Kootlets usually glow and spread in all lircciious from tlie taproot. 11l tiu> cuso of wheal, ami oilier sin-face-growing; plants there in not a taproot. Jtoollets instead grow and spread through Ihe foil which surrounds this seed. Tie: M>il puinlo of growing root,-, do not lore through solid clods or firmly-packed earth. Thoy push through iho open spiu.e.-, lieIweon the particles of the foil, grow rapidly, and the hairs on the rootlet.-, cling to the particles of tlio soil in which the* plant, as a whole, is firmly fixed. TiirMi luii i perform an imJKirtatit function in the nourishment of Ihc plant. When the embryo has germinated and commence* lo grow Ilia young plant at lirst receives its nourishment from ihe thick masses to which the embryo was, and slill is. attached. When the root is firmly lixod in the soil the plant food i.s no longer supplied by ihe feed, hut is laken directly from the soil through the rootn and from the air through Iho haves. As soon as this occurs two fresh conditions, in addition In lho:e novssary for the germination of the soul, are needed for the growth and development (if Iho plimt—nniuely, cerium pot lions of Iho toil and light. The principal p'irls < f tiK,sl plants are-(a) the root, (li) Ihe sl.-m or Irtiiil;, (c) tin! leaves, (d) the llr.wcr, and (o) ihe fruit, wiiich usual!v contains the s.,d. Kueli of these parti" is call.tl an organ. ICacli organ has st.cc.ial work to do, and that vxirk is called lie) function of Iho organ. 'Hie function of ihe root is In hold Ihe plants lirmly in the *oil, lo lake up iiotirishuiciit for the plant from lliu soil, and Motniliinis lo More up foodsliiir.s for tin; Use of the plant, as in the cum-; of the iK'a, wheat, turnip, mangold, and Iho frtiils. 'Hie function of th.> Mi tn or trunk i.s to support the liranohe.-., haves, buds, mid llowors, and lo act as 2 c.luinni'! ihrinigh whivh lo ennvey Ihe iiuirishiucnt from Ihe r«Kits to the brandies, the leaves, the flowers, and tlie frail. The (unction of the leave.; is lo piovide a lai'ito Mirfaoo for exposing fit" idanl f oixl to the action of Iho sunlight and heat, and lo absorb oaiboine acid g:is from Iho iiir, Tlw functions oi Ihe flower and Ihn soil nif to bring alxral. the reproduclion of (he plant. The sulistanco of which plants, and the vegetable world in gfiierai are ioniied is calm tissue. Thin tissue consists of minute colls. Kaoh cill is a. very fundi loiiud Jnuly, and consists of a transparent oiitKiiln'skin, which enchscs. in the living iihint, Uie plant foul. When Ihe coll is dead the inside or interior contains air only. The plan!•food, in the livini; coll, coiusists of an active, living stilistanee called protoplasm. As the plant grows the cells enlarge, (ho protoplasm galhers into a small i«uu«l ludy in the centre of tiie cell. I'ibros spnvul out front thin small round Ixidy, and tittach tlh'iiiselvi':; lo the aide of the cell. In time the cell divides. :■».! each iniliioii forms a now cell, lly this piiHi'ss "I enlargement and division of the colls the. plant grows and incroan'.s until it arrives at ti-alurity. The loaves are continuous with the skin or bark of the plant or tree, and their format ion is simple. I.ay a (jreen loaf on a flat surface, and cut it in two with a sharp lodic. Now, examine the cut edge through a tnieivsc«i|ie. It will he sivn that a thill and ilelicuto, ••kill divers the leaf on caoh side, and imuuiliilely Ik'loa - Ihe skin is .1 lavor of closelv-iwckod cells. 'I'oivanls the interior of tlw leaf several layers of loos'ly-)tucked cells are seen. Tito fkin of the leaf hits many minute uponings, which ojieii imvo widtdy in sunlight lhau in darkness. 'I'iic tissaio of lb.- plant piopcr is ihtb in ctitnplele union with the lisaio of Iho loaf, and the circulation in complete and imitiiiiious from the roots to tlio leaves, The t-teut and th.' brandies o: a plant or tree are Usually iliiidul ar fairly regular tlistantit. inlo bilious. Where those join, a raised line; runs around the Mem td Ilk' branch Those rais'.d tings aie called iit»ks, and it i» from these' rings that the leaves arise. During attltitiiti buds aie formed, either at the ends of the Mollis and branches or at ih'v nodes. Tile bud itself, and its circulation, are a'xi txmtimioiis with tlio ii.->ue of Ihe stem. Thoy aiv illicit ptxuiTliil fiMiu (old by a covering of scales, oi resin, of or of hair... Uuriiig winter thoy icnuiin as ihey weto formed in aiitiiti'i!. lirowih l>egii\s in the spring, and the buds d.'velop into leafy branches, which may form either leaves or lionets, or both. Inftoe.d of only groivine longer, they may grow in width. When the bud grows into a flower, the object is lo bring altiu! the reproduction of iho plant bv rcprvdiiciuj; mmiL Klow.-r, are 'of man'v a,„i focus. A icvftvt tlower coitsisls oi ;a) Uie c.ilyx. |ln the viiroll.l, (v| the siameiv, (d) the pistil. l'ro m the jsoint where the tlower join. th,. >ialk, s,.puratt> pitves. peiiorally of a green colour, form a row Aixiuuil Iho out.<it!t> t>! the tlower. This oiit.sitlo row i,s the calyx, Within the calv.x is a second ring of separate pi.cos. Tli.-se are luvirly always white, or coloured. hardly over groon. This row i.s oiled th,'. corolla. It sii'i'otes a niiiary jui.s.. ealletl iKi'lar. which ullrjcU itMits. >~ t|,,t |\, nvor Within the or second row is a third row. usually formed of sh-uder stalks, ealletl M.iniens. and on the top of each slalk i> a uninll Wiiich holds the iM.vder known its polloti tJi.it is iKWSiry for fertilising the mwl. Tho fourth riiiß assunit'S more forms than nttv ot.iiei; part of the flower, li. simplest form w tJie flower of the ism. The pistil of the common pea it. simplv a loaf folded down tlio middle, with it-> odtji's uiiittd to (orm a hollow ves.sol ciil.il tlie ovary, or vessel which contains the se.il. If a tlower has all these runs, it is a |n»rf.vl tlower. If any row In- ab-oni. the flower is imperfect. Tlio use of the ovary is two-fulil. It sccrotos little gruips within it* caviiv. It als" prorititts the moans for conducting lJu> pollen fiom the siatnoiis t<> it.< interior. The pVhti nny In' contWtctl to the ovary cither bv direct contact of stamen with pi-til bv insects, or by the action of the wind. When the |ndlen Jias roschtil the tvivity of tiie ovary, the little /rains in thrt cavity are forliliK'd. and Ihmius? mxil. titttil, in title ivtirse, to reprtilutv the plant. Tito food of the plant is derived from two source*—from the soil, tliroui'li itr rotit.s; and from the air. through its leaves. Tlio hairs of the rootlets, as i«> have won. cling to particles of ih.> vi\. The .oil is j. I.iltoriiiory In ivhioh solmions of plant Wd are conipoundod. T'o plant, atit! osis.xi.illv tlio roots, oxude cci.l salts, which Jiave the aided bv «at.y and t-ar-bonio arid, to d ; s«olvi> nnd \v<:'<; into the nlatit various useful mat' l "" ,lv " w.iro p r o.

viously Wins outside the roots insoluble in water. Tho hairs nf the rootlot.s arn formed of cell.-, it exceptionally minute hag.s. Thi> outer skin of the cell or bag it called th>. wall,: of He col'.. T'hi.so parti of till' liquid .solution llt'.is formed in Iho soil, which are suitable for ihc foi:<| of the plant pas* through the walls of the cell. iii:il bv tin' fi'isiii' precox ■•much tin' same as ;liat l.v which oil smnis a wick. Tii«j leaves al-soih air through the small otK-ti-iugs or pores, fr.fiiiir' tin' leaf, the air is ,i.-')lvec| into nitro-.'oii and oxygen. The oxygen i- liberated and the nitrogen incwporaled with t!;<' plant food, which has aii.ved fiom tlio ro..ts. Tho whole is ex-j.ii-i-i! So the action of sunlight, and convcrl'd into plant food, much alter tin: manner a housewife makes bread from Hour, mi!!:, "all, and v. a-1. 'J'iie house-wife i-. Nature a-line "'• 'If -hnji- of Minlighl; tin' Hour, iin- -all, a::d ycai-; ar.' provideil l.v the conjoint in,ion of the plant as i:.e carrier from mill or lalmra'.ory in ill.' t:il; and the inani-faelured plain hod i. '<■»; to >ve-v living part of tlio plant in he n:-'.i fur ihe growth, the sustenance, and the reproduction of the plant, ill much the same wav a.s a Imntrrv .-■hoollK.y cats- up his dinner. As the n'iionllxiy wants water or tea with his fuid f.i t!:e plan! ro.i|Uir.r- water. The water :.-<•.■«!., 'l.rolludi til" loots branch.-. and arrive;, at the leaves, not 10. i,:i-c:ng from tell to ceil, as the plant tVd doc/, hut ihielly through ihe fibrous- parts of the plant; and it tor, Ihrctigli thee parts HKir' rapidly than it could ;:o from cell to •-1I; ind the transmission ~f Ixith plant f<i«l and water is much more rapid in snnIL'ht than in darbies... There are thus two movements constantly going on in th ■ living, healthy plant-(a) the movement of tie- plant foul from coil to cell, and (li) t!"; n:'ivt'ii::':it of water from the roots to the leaves. The normal Movements of the plant food are Ikiili upwards and downwards from ihe factory or hdioratory in the leaves. All growing iilaiib uml trees rcc]iiirc a vcrv largo amount of water. Turnip, contain over C-3 per cent., or 'jO parts out of every 100 parts, of water, and watercress £(> cor cent. The water, having P'is-ed through Ihe plant or tree, is e.\haled liv the leave:'. If a window in.'lt or other frauiifl glass In laid on grass the tda.s-t speedily Incomes clouded from the w:iHt iw.ipinjj from llie grass Kven in the driest seasons, if a cold l>ellgl.-iss. l.e placed over gras\ water cuoiiu'h to trickle down th» .sides of ihc \vj|| he <lop:-sitod in a few minules. An acre of Brass evhiile.s n largo ntiiiiher of hothead, of water in a day. Ilre.it. mavises of any foliage give olf great quantities of water daily and prevent itagnution. .Most plants that farmers cultivate life up over 201 limes their dry weight of water. A singl" plant of kirloy, in full growth uml vigour, rupiirw the passage- t luvnijrJi it while in Iho mul of more ihan a gallon of water. An ucre of cabbages, in full growth, will use. more than 10 lons of 1 water in 12 hours. It is very evident, then, that if miier in lanje quantities lv not available for growing plants their jrniwih and dovelonmenl are stunted, and imperfifl crops, iiMiltitiif in serious less, are lit? cotifoqneuce. Tin- evaporation of tlio water from the leaves keeps the plant cool, even in lln> .liiitirfi wrallior, If a plant llm-i constructed and nnnrished h» placed where it cani'.ot receive the sunlight and heat it hreomes of a sickly white colour. During Iho process of manufacturing and oxidizing the, plant food in the plant laboratory n certain amount of liont is evolved by the oxidation within the plant, hut tii.it heat will not prevent the plant, in the ahpi'iiee of puiilitfiit. from losing iu tnlour. Hut if placed where it can receive sunlighl, it ipiiehiy a licaltliy and vigorous appearance, and hettinuis, while ?rowin[r, mostly of a green colour. Tlio sunlight nets on the carbonic acid in the leaves, and prraliwca Kirlwn, without wliitlt no green plum cm grow. The foliage of young plants cannot even exist for any leiiKlh of time, when oxjumwl to wmlighl in air thai i.s totally free from cnrlxmic arid. L'arbonio ;vei<l enters the hvives very .muc-li as tlio liqiiitLs- flnlur the roots. The ainouiil. of carlwiiic acid diconmosed (lo]v.miiKs on the intent-ty of the light; and the prosperity of llin plimt (kuiemls htrgelv ii|xui the amount nf light it receives. VVhon a rav of Minlight pn«-«s ihrough a threesiih'd piwe of ghuii it is found hi consist of' t ntimlh-r of dilTerentlv-culourotl rays. When t!»> sunlight onler,- ihe leaves fir the (lowers of plants, the pat'lioJe.s of which the leaf or the llowur is fcrmeil, act on (he light exactly a.s the threosiilcil pieee of gj.-i.-s itcled. Tl'.e rnv i.; resolved into tlio (litI'oiTntlyiolniiivd irnyis of which ie. w a.< composed, one of the rays lieint; rollorl.-d to ilu; eye of the o!:scrvei', and tlio remaining rays alrorM by the plant. If the T«l ray lv reflected, the loaf or the flower will nppmr of a rod colour; if tlio |, r roPn my U' reflevited, I lie to'our of the 'oaf or the llowor will lv (jroen. In this way. (•unliKlil colour the p.vs, |hp Icavw, itn.l the flowers. Hut the snnliglit does more tluiu prodiKV colour. The -uulieiuu contaiits liml rays, in addition lo Iho iiiy s of eolom-. Tlnte lu-at rays, in conjunction with lliu carbjiiio acid gas. act on iho plant fond, nnd; el icily in the day tinio, nuvert iho phint foixl into stnivli. 'l.itri'oly in the iiightime this .starch is tonverled it.to sugar and other nourishing suhytances, and sent lo all partd of the living, ly.-althy plant, lo tiouiLsh it. If a nlunl, thus prodinvil from a seed, !>:• iilaccd on a ri-d-hnt phito of ii.iii. most, of it will vanish into air. and a small pari, Iho tushes, will remain on the plate. The imrlion of the plant tlwl vanishes is called Ihe organic part, and the nnhcs that remain on the plate ai\» «illnl the inorganic part. If a growing plant of 1001b in weight lie burnt, it will usually ho found that 9511> wil' thus vanish, :u:<l only nlxiut slli of ashes will remain on the plate. The organic |>arl of tin; plant which vanish <'oii>ist> chii'llv of woody lilire, st.ircJi, mijjt, gum, oil, and fat. (.Jhoini.sU can ntluev all tlie;c into jjas's, or into Milt?t;|W'iv<, iniich rimpler than themselves. The chief of llie.'t> uro oxygen, hyilrogv-n, nilitigen, and carlmti. Osygon and nilrouon ..re the gases which form the air wc breathe. Oxygen and hydrogon form water. The inorganic part of a plant consists mostly of lime. lu.isTiiesia. lodr., |<ita.sh, iron, mangaue-e, satid. iodine, and various aciik It thus appears tiut plants ctmsist of the ordinary jlascij t>f nature, aiul Ihc ordinary substances of tht! toil. We shall endeavour to show how all those substances hud their v.-ay into the organism of the plant. 'I he of moii>um> in the utmcfphcic.ilono is of iiltje avail for the successful giimth of vi<><«.' The va|iour must l» con iloiU'd, fall in rain, and pi'iii'irale the soil The liiiit chief o-ndeiusers aio—-(a) tn'cs 'ami foru.l.s. (o) hills and imiunl.iiiis, (c) odd derived froui any .-oiirw. .Many instances could be given, such as ;it Honolulu and Triiiidaii, whei;e forests criminally ixisied. and until lh-.*v wcu cut down the raiiifnll was Hiiflicieut and regular. After Hit' fi.-rvvti wort; cut down the rainfall l.iitcjy dixTßisi'il. and tin- rain foil at irregular intervals. No sooner had ir-es Nh-ii tixtcn>ivelv grown again than the rainfall again inereanxl in quantity and lnvaiiic more regular. In New Zealand mountaiiki aiul luri*ts the vapour in the province of Wtv-tiatid, and a rainfall of (turn 3?. to 115 ini'liiv tir n.ore i* the lesnlt. lti the province of Auckland liiite itiiitlen.-er> are larg-'ly alwnl, and the iv'n.vtpioniv is a low rainfall of from S'") to 53 itni.iv yearly. In AiiHraiia ;i range of mountains runs, roimhly, parallel with the ea-t ctxi"tliuc, and u.ually at nuiio ilislanio inland, llctwoon tin moiiiitains and the ctnist'uie the rainfall is high an,! ivgul.rr. while on the va-l I l.iins of tile interior it is low and irro-

g'dar. Whore cold air eunwi's exist, whether the res-nlt .-i permanent atmos pi't'iie t'oiiililioiis, or indtiood liv iho pro-•.-.tee of iarge sheets of water, then the i.iihioneo of such ooiuioiisvis m conlmitiug the air, and hence eausiii',' it to pretipitato its vajsv.ii' in the form of lain, is jJi-oat and apiviretil.