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Fluid Journal : Fluid Journal 1993-1995
2 Fluid Journal Spring 1994 Table 1. Land use at Open Grounds Farm, 1993. Acres Corn 11,762 Soybeans* 14,119 Converting to crop 300 ASCS deducts 775 Pasture** 8,727 Total cropland 35,683 Forest 4,730 Building sites 74 Roads 921 Canals 588 Field ditches 1,220 March, etc. 971 Total-all land 44,187 * Soybeans are often double- cropped following winter wheat. ** Farm manages 3,500-head cow/ calf operation. increasing the probability that denitrification in ditches will prevent nitrate movement into surface waters. Systems approach Open Grounds approaches fertilization of its corn/winter wheat/ double-cropped soybean rotation in a systematic fashion. Soil testing. Fertilizer management begins with soil testing in the fall. Each 40-acre "cut" is divided into three 110- foot by one mile sections that are sampled annually. Soil sample data are then computerized and recommendations generated for spring fertilizer applications. Prescription blending. Open Grounds manages its own suspension plant where numerous fertilizer ratios are precisely formulated to satisfy field requirements. Mapping. Following formulation, applicators are given field maps that ensure prescription NPK blends are precisely applied in 13.33-acre blocks across all crop acres. "Systems" thinking is extended to all farm management activities at Open Grounds. For example, preplant N for wheat is applied at three rates within each field. Applications can vary from 40 lbs/A of Nattheedgesofafieldto20lbs/AofN at its center. Soybeans are fertilized with P and K prior to fall wheat planting so that both crops may benefit from nutrient applications. Lime rates are chosen with the idea that no-till corn will follow wheat and double-cropped soybeans. Starters At corn planting time, starter fertilizers are applied from 12-row planters via knives that deliver 10 gal/ A of a 1:1 mixture of 11-37-0 and 30 percent UAN, approximately one inch from the seed. Mixed with the starter is one qt/A of fertilizer grade Furadan 4F. This application of liquid Furadan from a closed sys-tem is less hazardous to equipment opera-tors and wildlife than granular soil insecticides used in past years. Moreover, the liquid insecticide, in tandem with the starter, provides effective control of wire-worms and Southern corn billbug, the area's most serious insect pest. Total N applied to corn at Open Grounds has ranged from 190 to 230 lbs/A. No-till corn and soils with lower organic matter receive the highest rates. N in the suspension plus the starter (20 lbs/A) ranges from 90 to 110 lbs/A. The remaining 120 lbs/A of N is sidedressed as UAN approximately six weeks after planting. Open Grounds has worked for a number of years to ensure that N application rates are optimal. Denitrification rate studies are under way on the farm. Other studies are examining the feasibility of using nitrate electrodes or chlorophyll meters to predict N sidedressing and top-dressing rates for corn and wheat, respectively. Plant tissue testing is also extensively used, particularly for wheat. IPM Open Grounds Farm operates a sophisticated pest management program whose activities are coordinated by the farm's crop manager, Sam Brake, Jr. The Integrated Pest Management (IPM) department fields two crews that focus upon pest management. Its product and scouting supervisors report to Gabriele Onorato, the farm's pest management coordinator. Product supervision. Crew I is responsible for the mixing of pesticides and other chemicals, supervision of ground and aerial application, control of pesticide inventories, and maintenance of spray records that includes documentation of the storage and disposal of rinsate water. Pesticide mixing for ground and aerial applications is accomplished on a completely enclosed concrete pad equipped with a spill collection system. The mixing area is 200 feet from the water source. These precautions are accompanied by annual pesticide safety training for each crew member. Special efforts are taken to assure all pesticide and fertilizer equipment operators are aware of the importance and sensitivity of the environment surrounding the farm. Scouting. Crew II is responsible for monitoring crop weeds, insects, diseases, and weather conditions. Weeds are normally scouted at least twice per season. For example, first scouting for weeds in winter wheat occurs in January, prior to the crop's first nitrogen application. The second scouting occurs ten days after final nitrogen application on wheat. Later trips assess wheat insect and disease pressures. Scouting has become the cornerstone of Open Grounds' efforts to farm profitably in one of the nation's most environmentally sensitive areas, Scouting facilitates early detection of nutritional and insect problems. It denotes type, size, density, and location of infestations. Rigorous scouting, combined with economic thresholds (predicted by herbicide decision model developed by North Carolina State University), enabled Open Grounds to reduce its pesticide expenditures by more than $120,000 in 1993. For example, the traditional gallon per acre of pre-emergence Lasso for corn and soybeans on organic soils has been replaced by applying postemergence products only when economic thresholds justify their use. Figure 1 shows how the farm's remedial
Fluid Journal 1996-1998