Fundamental studies on salt water irrigation under arid conditions, 1: The movements of water, Na+, and Cl- in dune sand column
1990
Yamamoto, S. (Tottori Univ. (Japan). Faculty of Agriculture) | Honna, T. | Watanabe, H. | Yamamoto, T.
The movements of water, Na+ and Cl- in a dune sand column with plants under arid conditions (temperature 30 degrees C, humidity 35%) was investigated by adopting drip irrigation and ordinary irrigation with 2000 ppm of NaCl. The experimental term was 7 days and the top of the column was covered to prevent evaporation from the sand. The following differences resulted from the two irrigation methods. 1) Drip irrigation kept the upper part of the column in a moist condition during the experiment, but the lower part gradually became dry. With ordinary irrigation, though the water content was kept constant throughout the whole of the column, that at the upper part was lower compared with drip irrigation. 2) The distribution of water soluble Na+ and Cl- corresponded to water distribution. As compared with ordinary irrigation, drip irrigation accumulated a greater amount of salt at the upper part of the column. This part, however, contained much more water, so that the salt concentration in the soil solution was kept lower (about 50%) during the experiment. 3) When the total evapotranspiration was less than the amount of irrigated water, the above differences between the two irrigation methods were not clearly observable
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