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• <br />• <br />• <br />Burbridge grass hay fields is proposed as the basis for developing the standard for grass <br />hayland. The 1987 baseline vegetation information is considered the first of the three <br />year's of data. In determining historic production, the affects of climatic variation on <br />production will not be a significant factor because of the availability of irrigation, <br />sufficient irrigation water available to the operator during the growing season, and <br />similar management is from year to year (Ward Burbridge, personal communication, May <br />1987). This reduces the need for long term data collection due to climatic and management <br />variability. In addition, it appears that a precedent for a three year data collection <br />period on irrigated cropland is set in Rule 4.25.5. Therefore, it is proposed that the <br />success standard be based on the above suggested three years of historic data collected <br />from Burbridge's grass hayfields. The yield value determined from the reclaimed grass <br />hayland will not be less than 90 percent of the mean with 90 percent statistical <br />confidence. <br />Rule 4.15.9 requires that only production be evaluated for areas included under cropland. <br />Irrigated Pasture Type. The revegetation success standards for this type are based on the <br />establishment of irrigated pasture as the postmining land use. Irrigated pasture should <br />be able to attain a good level of productivity with only one to two grasses and a legume <br />under continuing and adequate management inputs. This includes scheduled irrigation, <br />annual fertilization based on soils tests and plant needs, and grazing management or <br />proper harvest methods. As stated earlier in the discussion on revegetation of the <br />irrigated pasture type, and supported by references therein, annual fertilization of <br />irrigated pastures is part of the normal husbandry applied to maintain vigor and <br />productivity. Thus, it is requested that the restrictions on augmented irrigation and <br />fertilization as spelled out in 4.15.7(5) and 3.02.3 be waived. Furthermore, and <br />supported by the earlier references, the requirements for establishment of woody plant <br />densities, species diversity, and seasonal variety are irrelevant to the irrigated pasture <br />vegetation type and postmining land use. Properly developed and managed irrigated pasture <br />differs from irrigated hayland only in a small differences in species composition, <br />slightly lower productivity (related to the differences in composition), and the <br />substitution of grazing for mechanical harvest. Therefore, the standards of revegetation <br />success for the irrigated pasture type will be based on production and cover. <br />The production standard will be based on the SCS Soil Interpretation Record (Form 5's) for <br />the Progresso soil series, representing a large portion of soils which are irrigated in <br />22-31 Revised 07/25/91 <br />