OCR Text |
Show WATER NEEDED FOR ORCHARD i ! Moisture to Depth of Four Feet at Least Required for Proper Development De-velopment of Roots. In nearly all orchard irrigation work too little water is given. When only a small quantity is applied it draws the roots near the surface. Much oi the water is held in the mulch and ia again lost when the mulch dries out. In the first foot of soil practically seven sev-en inches is open space and into this the air and water enters. Four feet at least is required for root development, develop-ment, writes R. L. Adams in the Denver Den-ver Field and Farm. In order to completely com-pletely fill this a corresponding amount of water is needed. This, however, would result In saturating the soil. In actual practice ten inches of water applied to sandy soils and eighteen inches to clay lands will give the best results. Not all the moisture is available avail-able for the crop's needs. Part of the moisture is held closely to the soil grains and will not be given up to the trees even under very dry conditions. This hydroscopic water amounts to an immense sheet in the aggregate. It is this water in which most of the plant food3 are being dissolved. This unavailable moisture is greater in clay than in sandy soils, as' the amount of surface of the smaller grains is vastly larger than for coarse ones, just as marble has a much smaller surface while whole than when broken into a thousand fragments. For this reason the percentage must be maintained at , a higher point for moisture in clay soils than for that in sandy lands. On the other hand, sand soils will dry out much quicker than clays. On the other hand excessive irrigation irriga-tion is to be condemned as it carries off the soluble plant foods. If these go into layers of sand or gravel, or into the water table, they will be carried off into the natural drainage of the country. If the irrigation water goes deep, although still -remaining in the soil, it will carry these salts below the reach of the roots and the chance3 of being returned within range will depend de-pend on the character of the soil in its relation to Its capillary power and tha depth to which they rest. The layers of gravel and coarse sand effectually cut off capillarity and the water carried below such layers with its attendant supply of plant food is lost. Therefore sufficient moisture to just reach the desired depth is all that need be given. The need can be determined by both the appearance of the trees and the soil. A slackening in growth and a darkening in color of the foliage are indications. But as the water Ehould not fall below a point to create appearances in the tree careful care-ful watch must be kept on the soil itself. it-self. Care should be exercised to see that the proper degree of moisture exists ex-ists to the full depth of the soil. |