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Show DRY FARMING SOILS Addition of Humus Does Not Increase In-crease Availability of Water. To Secure Greatest Benefit Barnyard Manure Should Be Applied In Small Amounts and at Rather Rath-er Frequent Intervals. That the addition of butnus to the soil In the dry farming regions does not lucreasa the availability of wuter in the ground and that humus bearing material barnyard manure, straw, leaves, or other vegetable matter should be added to the soil frequently In small amount, are conclusions drawn from experiments recently conducted con-ducted at the experiment station ol the state of Washington, says the Country (ieiitleman. The basis of the experiments, was soli taken from the dry fanning zones, one cubic foot of which, without humus, weighed eighty pounds and was capable of absorbing and retaining, retain-ing, without drainage, "& per cent, ot Its weight of water. Of the water, only 1 6.8 pound could be taken up by plant, wilting occurring when a cubic foot of the soil held but 3.2 pounds ot water. Seventy nlx pounda of thla aoll was mixed with four pounda ot humus, the soil being capable of holding hold-ing ID pound of water, and the humus four that I. I'll) per cent, of Its weight. A ruble loot of the humus-bearing humus-bearing soli retalnid TA pounds of water, wa-ter, while a similar amount of soil without humus held hut 20 pounds. Forty per cent, of the water held by the humus I.G pounds and 3114 pounds held by the soil were unavailable unavail-able to plants. iince In one cubic foot of soil without with-out humus, containing 20 pound of water, but 1H.N pound were available for the growth of plants, In a tier or three cubic feet of soil MA pounds of water were available for plant. To make this amount of water available in three cubic feet of soil without humus hu-mus a volume of water a foot square and 12 Inches deep was required, the amount available ail. 4 pounds- being equal to 9.7 luetic of the depth indicated. indi-cated. With these facts In mind the next problem wa to find how many inches of water would be I. Pliable to plant growth when live per rent, of humus was put into a cubic foot of soil. In the humus bearing soil, as stated, from 23 pounds of moisture retained 18 3B pounds were available for the use of plants, it was found that the soil containing humus absorbed a greater amount of water than did the soil without humus, two and three-fourths cubic feet ot the former holding as much water as had been retained by three cubic feet of the slit. Hlnce 18.36 pounds of water were available for the growth of plants In a cubic foot of the humus-laden soli, two and three-fourths cubic feet held 6M1 'pounds of available water or a volume vol-ume a foot square by 9.71 inches deep. Hence, with no humus in the eoll, 9.1 inches of the given volume bad been available for plants, and with bumut added In the amount Indicated, 9.71 Incbea of the same volume were available. avail-able. Said lJrof. Clark C. Thorn, In discussing dis-cussing these results: "In all cases where humus Is added to the soil water wa-ter Is held nearer the surface and Is therefore more easily evaporated. Five per cent, of humus which Is as much as Is likely to be added does not Increase the availability of moisture mois-ture aud is of no direct benefit in this respect; Indeed, It may even be detrimental detri-mental In that it holds the molstur? nearer the surface, where it ts more quickly evaporated. 'The beneficial results of humus are In creating a new supply of plant tood and It Is always advisable, even Imperative, Im-perative, that humus be present In the soil. Clays are opened up by It. washing Is prevented and nitrogen Is supplied. "It is a common experience among farmers who add great a.tiounts of ma nure to their land to observe on the following; year that the crop burns where the fertiliser was sspplled. The reason for this Is obvious. The manure ma-nure they have added la able to retain re-tain Ita own weight In water, or practically prac-tically so, and this amount It at once absorbs from the soil. Of the amount absorbed, however, onlt about sixty per cent. U available for the growtn of planta, (be rest being locked up Mence the following year the soil Is actually dtled out by the manure, and burning, results. Hut the second year will show benefits from the use of the fertiliser, sitire It has by this time stored tip Its 40 per cent, reserve, re-serve, retaining this amount of moisture mois-ture In excess of what would other wise be present In the ground. "It Is thus made plain why farmers should not dump great amounts ol barnyard manure on their land at Intervale In-tervale of from three to ten years, as some do. To give the greatest benefit the manure should be added In small amount and at more frequent Intervals" |
