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Show WHEN THE WATER IS WASTED Deep-Furrow Irrigation Does Not Solve Problem of Even Distribution Test at Riverside. Furrow irrigation, wherever it can be practiced, is gradually supplanting other methods. In tank experiments it was shown that furrows, by reducing reduc-ing evaporation, cause a larger quantity quan-tity of water to enter and stay in the soil than does the basin method, and it was further shown that the loss of water was smaller as the depth of the furrow increased. Moreover, small quantities of water frequently applied showed a much larger loss than heavy irrigations applied at longer intervals and followed by thorough cultivation. Though deep-furrow irrigation seems: most efficiently to solve the problem of how to get the largest quantity of water into the soil, it does not solve the problem of even distribution unless un-less the irrigator thinks hard and ini vestigates closely. In order to determine de-termine the course, progress and distribution dis-tribution of irrigation water in the soil, a deep trench eighty feet long was dug across sixteen irrigation fur rows and four tree rows in a Riverside River-side orange orchard with loose, sandy loam soil, wooden troughs conveying the water over the trench during the investigations. The work was carried on by Dr. R. H. Loughridge of the University of California, under the direction di-rection of the bureau of irrigation investigations. in-vestigations. Upon the face of this trench the darkening color of the soil made it possible to determine accurately the downward and outward percolation of the water from the furrows. The sixteen six-teen furrows were made in eight pairs, the pairs being separated from each other by irregular distances, three feet being the minimum and ten feet the maximum." Unexpected results re-sults were obtained by a study of the water distribution. The water from only two pairs of furrows was found to have united. Between Be-tween the moist acres underneath the other seven palFs strips of dry soil were found. Furthermore, it was discovered dis-covered that the downward spread of the water decreased as the depth advanced, ad-vanced, giving the moist area a conical con-ical appearance, with the apex of the cone directly beneath the furrow, its base being widest about a foot beneath be-neath the surface. Upon more compact com-pact soil types similar conditions prevailed, pre-vailed, except that the water traveled laterally at a slightly greater rate and in several cases showed a maximum downward penetration of only three feet in three days. Despite the greater great-er lateral movement the space- in the center of the tree row was usually found to be dry. |
