HUMUS IN THE SOIL.

Auckland Star, Volume XLVI, Issue 61, 12 March 1915, Page 8

HUMUS IN THE SOIL.

We quote 'the following from a lecture given by Professor G. W. Shci w, on the above isubj-ect:—

'"The -nircnus quality of our eoHe lies not so nrueii on the chtmicaJ side of tlie soil as upon the wretchedly poor physical oorti&jfcion induced lUirougli the lack of any atltempt to return 'to the sol ti'iat viia-l uitibnibirte whiii'h rciakns for productiveness iiiiunue; wihoL'h together wijiih iraitibnal itiXn.ie 'And of manures, consti tubes the best kept for unlocking the storage of Iliteurt 'pL'aiot-food cbntained in the soil..

"Failure to TcaKse ilihe iropontance. of U>i3 oiloft vu-ta'l queinfcion. the rcsitontecm of ihunvus, is res-ponsibJe for la-eening the .robe.ntdvceieee of out soil 5 for moieture, mpeoiaMy in .the upper iiyens, a very sea-ous muitter in our c'.rsmute of fickle rainifall; a levs9erf.'Dg of our available ffijiraWO'Dd; Mc raakim;; 0/ the earl coMer, amd "tire increase of the cementing action in 'the eaee of 'hcnvy soils, and increasvng tftro tendency of. light soils >to drift.

"The .manret'cm'jiijee of fcintjlity or productiveness of S'oolii is very 'largely a matter of the upkeep of ite ibumup content. Tih-e first aod' < to the injured soil, abuepd a.ud depleted, shoiiTd be,,tp supply it with a poiod quaKty of ■Imnius.

"Hipmus is a variaiKe, inxleftnijtc sort of matter, diffieuAt to ,<.i\Ai-sify, chemically complex,. eonKitlnioi' liigMy nitrogenous and somatomes neariy free, composed 'of mixed awi'muJ and vegetable multteif —anoetily' the latter liin its intermedikiite forms of "deeanrpesitvon, but not complete.

"It 'is .the result of tfae , pjirfciall decompontioii of tlbe organic , maibfcer of eo'd, feav-cs, sticks, straw, stubble, irtrofcs, apd, greon 'bops .titrated under oral the like. During tihe process of dts fiirail destruction α-iid v'h'ile being <mude into mouW, tihis mait*(rji'l -is useful 'to 'tihe "soil. It was tihat which gave the liglhtnc&s and tilfch to it in >iihe earlier days -tifcanougili .ite acaumu'laitionfor- cou.r.*lc«3 y«a.ris, and ■wlhitih, ■whennwm bfgan to cuitiivate U>e eo.il, was ma.pjJ!jr destroyed. During ite foniiiatfon dt actabotlh in a tihemicai end •phvsicaJ capacity. '•'lt beneiiti itlie isoi'l •clwanicailly by supplying nitrogen directly; by supplying phosphonic aicid. potagih. a.nd (HTire ddreefcly. "It 'benefits the sm\ phyeicaiHy by augmenting dts va.t«p4wjM&ng capaicity; -by dts warm'tih; .by b<<titenii<g its testure, and bia/Ogku'Hy, by affording food imait-CTials for imacw> j oTgttJi.wj growth.

"Buimiia mtiy be mainitained end augmented by .thiree procedures—i.e., crop rotation, the use of iejm manures, and the practice «f giwe nmnwnag."