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r IV. CONCLUSIONS AND RECOMMENDATIONS The data presented above provides an approximate estimate of what will be occurring at the new facility with regard to nitrogen production, crop utilization and environmental stewardship. There are numerous factors involved in adequately assessing and correlating crop needs and uptake of available nitrogen. From the results of the nitrogen balance equation, the amount of nitrogen produced by the dairy operation is approximately 60% of the nitrogen needed for optimum crop growth. When large numbers are formulated to assess nitrogen produced vs. nitrogen required, the margin of error can be±10%. Therefore, it is recommended that sampling and analysis be performed on the following after the dairy begins operations: 1.)Nutrients applied, 2.) Cropland soil and 3.) Tissue samples of the crops to check for N excess. By analyzing these different parameters, it can best be determined which form of nutrient (liquid, solid or synthetic fertilizer)to apply to a particular field.. Additionally,the Estimated Nitrogen Release (ENR) must be taken into consideration when determining nutrient application quantities. This quantifies potential nitrogen release from previous crop residues. The procedures for determining crop nutritional needs,particularly nitrogen, without overloading the cropland can be a complex process. In an effort to simplify the information required to make best management decisions for optimum crop growth and nutrient utilization, we recommend the Manure Analysis Reference Guide, published by A& L Agricultural Laboratories. It provides one of the best sources of information to determine utilization of crop nutrients from confined animal facilities. The suitable rate of solid and liquid applications is determined by the ability of the soil and crop combination to immobilize and utilize the nutrients in the applied manure, which is detailed on the Worksheets found in this Guide. As referenced, it is anticipated the Borba's will sell most of the manure solids produced at the facility. It has been demonstrated that there is adequate cropland to accept all wastewater and manure produced on-site. An economic analysis should be done to consider applying manure solids to the cropland. If solid manure transfers for off-site use are made, records should be kept of quantities, destinations and dates. Because of the low nitrate concentrations found in existing domestic wells surrounding the new dairy site, we do not recommend monitoring well installation. Baseline nitrate concentrations of these wells have been established for future reference. Caution must be used when irrigating the cropland. Tailwater must not be allowed to enter any of the canals or ditches near the cropland by careful wastewater applications and the use of berms. The infiltration and permeability of all nutrient application acreage is comparatively slow and runoff can occur readily since the cropland will be flood irrigated. Because of the severe cemented silts hardpan layer, septic effluent management by the leachfield trenches will be nominal. Percolative capacity may be enhanced by excavating to 6+ feet and backfilling with pieces of hardpan to a depth of 42 inches in each of the leachline trenches. The calculated septic effluent acceptance rate for the bottom of the seepage pits indicates percolation of considerable effluent volume on a daily basis. However, biomat formation within the leachline trenches and seepage pits can impede percolation to an eventual equilibrium rate of 0.5 gals/sq ft/day. All septic systems have life spans due to this biomat formation. 9 valley Ag 9?fsearch