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'Plte Litvak area did not show any improvement in vegetation cover. It remained extremely week with virtually rio growth of the desired species. That failure led to the investigation of the cause. Those investigations are discussed in the next section. Salty Soil Remedial Program: After determining that the Litvak area was unlikely to show any additional growth, an investigation was launched to determine the cause of the failure. It was reasoned that there were two possible causes -poor seeding or soil problems. Because the failure was generalized over the entire area it was initially thought that the cause was poor seeding. However, because the growth environment is quite uniform over the entire area it was also possible that the cause was a generalized soil problem. To determine which of these was the case, the soil was sampled and tested. The results of the test are included on a separate page in this report. Although some of the nutrient levels are somewhat low (N and P), they are not so low that they should prevent the growth of the species planted. In both tests salts and sodium were high with salt being the most alarming. As a general rule, if the EC is greater than 4 salt will be limiting to growth. LITVN is a composite sample from the north side of the lake and showed an EC of 5.3. LITVS is a sample from the south side of the lake and showed an EC of 8.7 which is very high and intensely limiting. The SAR values are high and of concern, but might not be severely limiting. It was concluded that the failure of the seeding was not due to seeding but due to soil chemistry being too limiting for the species planted and recommended by the SCS. Several techniques can be used to reduce salt content, including leaching with several acre feet of water or total replacement of the soil. Because neither of these are feasible a different approach is being tested. This approach involves changing the species planted to species that are salt tolerant. This approach is further modified by ongoing research and revegetation work occurring at Tijuana Estuary near Imperial Beach, California. Although it seems strange to utilize in Pueblo, Colorado, techniques discovered in southern California, the fact is, from the standpoint of soil chemistry and growth as well as some of the vegetation, the two sites are amazingly similar. It has been learned at Tijuana Estuary that much of the initial succession occurs in a combination of both shrub and grass growth. If revegetation is attempted with just grass (e.g. Inland Saltgrass or California Cordgrass) the success is much lower than it is if shrubs (Four-winged Saltbush) are included in the revegetation. Salt levels in the more upland soils at Tijuana Estuary are similar to the salt levels at Litvak and Divelbliss. Therefore, from a chemical point of view, utilizing the approach taken at Tijuana Estuary might produce far better results at these sites in Pueblo. It was further discovered at Tijuana Estuary that with strong shrub growth it appears that salt levels in the soil can actually dec]ine, if the soil is not influenced by the diurnal fluctuation of mixed marine and fresh groundwater. Of course, in Pueblo there currently is no need to worry about salt renewal caused by water from the Pacific Ocean infiltrating the soils twice a day with each tide. Several species of salt tolerant grasses were planted in late winter 1999 on the Litvak site (see Map 4). Although other salt tolerant shrubs were desired to be tested (rabbitbrush and greasewood), only seed for Four-winged Saltbush was available. As that is a major shrub at Tijuana Estuary it was decided that would be sufficient for a test. Two of the grasses planted included the native alkali grass (Alkali Sacaton) and the introduced alkali grass (Alkali Grass - Puccinellia distanr). As the map shows, these two species are planted in separate zones around the lake. The reason for doing this is that both species are highly similar. Some taxonomists even consider them to be the same species. They are also almost impossible to distinguish in the field. If they were planted together then it could not be determined which was most successful or if they are equally successful. Therefore, they were planted in separate marked zones so a success assessment can be made. Examination of the success of this program will be made over the next couple of years. From that information, final determinations will be made as to what works best on these types of soil. If Divelbliss does not show better success, then the most successful species tested at Litvak will be planted there. Transit Mix of Pueblo 1999 Annual Report M-77-573 Pueblo West Pit Page 2 of 3