WSP09831 - Laserfiche WebLink

Home Browse Search

~ ~ ~ CJ 22 level 6 where sufficient water was applied to leach some salts below the 30 cm layer. The values of EC are lower for water levels land 2 because the amount of irrigation water, and accompanying salt, was very low. The data for the fresh water plot, Table 8, shows a decreasing value of EC as the irrigation level (and the irrigation amount) increased from levels 1 and 2 to 6. This is an indication that the salinity of the fresh water is so low, compared to the amounts in the soil at the begin- ning of the experiment as measured in levell, that leaching out of this top layer has occurred. Tables A-3 through A-10 in the Appendix show results of chloride and four-probe soil resistance measurements made from the same location as the EC measurements of.Table 8. The chloride concentrations show the same trend as the EC but the average chloride values in the salty plot are 13 times higher in the salty plots than in the fresh water plots compared to a 4 times higher EC. The 4-probe readings are sensitive to both water content and salinity. The data of Tables A-5 through A-8 show more of an effect due to water content (Tables A-9 and A-lO) than salinity. The higher the water content and salinity, the lower the resistance. The resistance of both the salty and fresh plots is lower at high irrigation levels (high water contents) than lower water contents. The resistance was 2.08, 1.44, and l.12 times higher at irrigation levels 3, 4, and 5, respectively, than for level 6. At the same irrigation level (about the same water content) the four-probe resistance was greater for the fresh water plot than for the salty plot. The ratio for resistance, for the fresh/salty plots, averaged about 1.3 for irrigation levels 3-6.