HUMUS.

Dominion, Volume 2, Issue 493, 28 April 1909, Page 10

HUMUS.

ITS VALUE IN A SOIL

Humus.-. is 'tho decayed and : decaying vegetable:matter in. the' soil. Any system of fanning'should provide for the continual' addmg to the soil of humus'to keep up the workable.condition;of the'soil. - ' ■ . ;, Tho vegetable .matter in the soil greatly increases tho .capacity>of' the-soil to -hold moisture. "In some cases-this, increase has ,to be more than- 25 per cent. TJie humus- prevents tho moisture from 'es-: caping into the air J>y iovaporatiou, but lets, go- of : the moisture on- the' request of' theit(ot that is looking for soil moisture con-' taming plant fcod. 'A 'soil well' supplied! with Jiumus will thus supply, moisture to plants in a drought long after tho .plants on other ground havo -.perished from thirst. Many a soil;that;has.been cultivated for a longtime and has had no humus added to it except what was added to it by the decay of roots lias become so compact; and- little told water. that it dries out very quickly in a droughty year. ■■ The continued adding of chemical 'fertilisers ..-to such , soils' has not giveii the results looked for because they could not increase the power of such soil to hold water, no matter how: much 1 fertility might be added. • .Therefore, humus,'in the form of greenstuff turned under, .should be added to the soil .with the fertilisers whenever possible. 'Ihe process of-decay of vegetable matter in tho soil liberates humic acid, which, plays.a large part in preparing plant food for tho use of plants. Where the.humus has been exhausted, the amount of humio acid let loose in the-soil is, correspondingly small. . ■•■■■••'. ; -l)ecaying _ vegetable matter in the soil' .make's it, lighter to work and more silky in texture.' Tho plough passes through it with,greater ease, for the mineral particlea do not cling together so closely. Where hu-" mus is abundant, the land does not bake quickly under, the rays of the sun. ,The : soil that lacks 'humus bakes, and is continually requiring attention from the cultivator. In a sou rich in humus, the shade given by _ the plants is enough to keep the soil moist and soft at the surface. Less cultivation has'to' be donb to keep the soil in -good condition for the : growth of plants. Where humus is abundant, soil bacteria work and multiply. These bacteria need thecarboa that comes from the decay of the vegetable matter. Soil bacteria multiply ' best in humus-rich soil also, because that kind of soil allows the passage into it of air. The more humus there is in the soil, the deeper wjll the soil ultimately be, for the earthworms will work if down in their upward and downward passage. The deeper the soil, the deeper will go the roots, of the plants, and tho less will those plants be affected duririg long periods of drought.