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Die Bodenkultur - Journal for Land Management, Food and Environment
A. GENEAD, H. G. FREDE, D. LÜTKEMÖLLER, H. NEURURER and W. STEINMAYR:
Potentiality for soil erosion control and improving plant production in arid zones
5th Communication: Field trials for increasing water efficiency by soil improving agents
Investigations in the field have been carried out in order to examine the water retention effect of different soil conditioners. Preceding extensive laboratory experiments were necessary by which the evaporation-inhibitory effect of several bituminous emulsions and synthetic polymeres has been proved. The trial site was an irrigation-perimeter (Center-Pivot) on light sandy soil west of Ismaelia in North-Egypt. Potatoes were cultivated as test crop. The trials were carried out with normal and reduced irrigation. The results can be summarized as follows: 1. The reduction of irrigation leads throughout to lowerwater contents in the root-zone, where the water contents of the variants with improving agents were higher than without them. 2. Yield is reduced by lower water-supply, but it was higher when the improving agents were applied, even at a reduced water amount. 3. The economy of the applied water, determined as "water use efficiency", is basically higher at reduced irrigation than at normal irrigation. By application of the soil improving agents it will be increased additionally. 4. The optimal amount of the irrigation depends on the fact whether water is a limited production factor or not. Key words: Field trials, soil improving, erosion control, water increasing.