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- Author or Editor: Richard L. Parish x
Application uniformity of fertilizers and pesticides is critical for crop uniformity, but can be difficult to determine when a fertilizer or chemical (fertigation/chemigation) is applied via drip irrigation or deep irrigation tape. Three injectors (venturi, pump, and proportional) were compared in a greenhouse experiment with a continuous-injecting experimental plot injector for fertilizer distribution uniformity in a drip irrigation system. Injection rate and solution volume were evaluated in a field experiment. Injection rate had a significant effect on fertilizer distribution uniformity. Better fertilizer distribution in the greenhouse experiment was obtained with venturi and proportional injectors. In the field, better distribution was obtained with the 1 gal/min (0.06 L·s-1) positive-displacement pump than with the 3 gal/min (0.19 L·s-1) pump. Injection times were longer with these injectors than with the other treatments, with the exception of the continuous injector. Injectors tested in this experiment will give uniform fertilizer distribution if the injector is properly sized with the water flow rate of the system.
Field studies were conducted in Fall 1991 and 1992 to determine 1) if cauliflower (Brassica oleracea L. Botrytis Group) could be precision-seeded to a stand without subsequent thinning and 2) the optimum seed spacing necessary to directly seed cauliflower to a stand. Seed spacings of 10, 20, and 30 cm at one seed per hill and 30 cm at two seeds per hill were evaluated for effect on yield, head weight, plant population, and early harvest percentage. As evaluated in the laboratory, seeder precision (accuracy) was good in regard to seed counts and spacing measurements at the various seed spacings. In the field, seeder precision varied in distribution patterns among seed spacings and years. Cauliflower directly seeded at one seed per hill and a 20-cm spacing produced yields and head weights similar to cauliflower seeded 10 cm apart and thinned to 30 cm—the seeding method currently used by some commercial operators.
Field studies were conducted in Spring 1989 and 1990 to determine if cabbage (Brassica oleracea L. Capitata Group) could be precision-seeded to a stand without subsequent thinning and to determine the optimum seed spacing necessary to seed cabbage directly to a stand. Seed spacings of 10, 20, and 30 cm at one seed per hill and 30 cm at two seeds per hill were evaluated for effect on yield, head weight, plant population, and harvest percentage. Seeder precision (accuracy) with regard to seed counts and spacing measurements at the various seed spacings, as evaluated in the laboratory, was good. Seeder precision evaluated in the field varied in distribution patterns among seed spacings and years. Cabbage directly seeded at one seed per hill and a 30-cm spacing produced yields and head weights similar to or higher than cabbage seeded 10 cm apart and thinned to 30 cm-the seeding method currently used by some commercial operators.