ABSTRACT Amodel for predicting layer performance as a function of inside temperature was used to determine the effects of evaporative cooling and local climatic effects on economic return. A stochastic weather model analysis was used to determine the effects of geographic location upon production with and without evaporative cooling and the effect of flock placement date. The stochastic analysis demonstrated the need to use a minimum of 50 years of replication to reasonably determine expected performance due to significant yearly variations in production response. Yearly variations were particularly large for the number of eggs produced and their distribution by size. The stochastic analysis yielded very different results than an analysis using a deterministic weather model, which has been the normal method of analysis to date. The simulation results strongly indicated that evaporative cooling can provide significant production benefits even in moderate northern climates and that flock placement date strongly affected expected returns.
Baby spinach (Spinacia oleracea) was grown in a bench-scale deep-water culture (DWC) system in expanded polystyrene (EPS) plug trays. Two experiments were performed. In the first, different seeding patterns, [1-2-1-2…] or [3-0-3-0…] seeds per sequential cell, at the same overall density per tray, were compared to evaluate the potential of an EPS tray designed with fewer cells, but sown with more seeds per cell (to preserve canopy density). Using such a flat would lower growing substrate requirements. Seeding in the [3-0-3-0…] pattern reduced seed germination, but only by 5%. Harvested fresh weight was also less numerically in the [3-0-3-0…] pattern but not statistically. The second experiment observed cultivars Carmel, Seaside and Space grown concurrently. Carmel had the highest germination, nearly 100%, which was significantly greater than Seaside but not Space. Germination for Space was not significantly different from that of Seaside. Carmel also had the highest harvested fresh weight but was not significantly different from Space; both Carmel and Space produced significantly more harvested fresh weight than Seaside.
A field investigation was conducted during cold and moderate weather to determine the within house temperature variations in high density caged layer houses and if there was a relationship to the inlet flow characteristics. Data collected at fixed cross sections from five different houses showed an average maximum temperature variation of 5.5C. During periods of moderate or low ventilation rates, temperature variations had a low correlation with all the inlet flow characteristics as described by Reynolds, Archimedes and jet momentum numbers. This suggests that inlet jets are not capable of consistently maintaining uniform temperatures in currently designed caged layer poultry houses.
Genius is 1% inspiration and 99% perspiration. Accordingly a genius is often merely a talented person who has done all of his or her homework.Thomas Edison
The depth that bubbles will penetrate a receiving pool before rising due to buoyancy forces is an important phenomena in designing Low Head Oxygenator (LHO) devices, particularly in an indoor application where the available elevation between the top of the fish tank water column and the inside ceiling height is limited. The relationship between bubble loss and LHO geometry is unclear. If the submergence of the LHO is less than the bubble penetration depth, excessive escape of bubbles can increase operating costs substantially. A series of physical experiments were conducted using an elevated bucket with a single orifice to create a falling stream into a receiving pool. The primary variables of hydraulic head, hole diameter and fall height were varied over a practical range for such applications. Videotaping was used to analyze bubble penetration. Regression equations were developed to predict both bubble penetration and standard deviation associated with a specific set of operating conditions. The standard deviation regression equation can be used to predict the statistical variation in bubble penetration depth. Bubble penetration depth decreased as fall height was increased and became stable at a fall height of 50 cm. Bubble penetration increased as hole diameter was increased at all fall heights and hydraulic heads. An example is provided of how to predict bubble penetration depth to meet some user defined statistical confidence for maximum bubble penetration.
Interest among consumers in the availability of organically produced fruits and vegetables is increasing. Seafood demand is increasingly being met by fish raised using aquaculture methods that provide fish excretory products that can meet organic standards for nutrient sources for organic vegetables. We conducted an experiment in a glass greenhouse to evaluate fish biosolids as a substrate amendment for organic tomato transplant production. We compared the fish biosolids treatment to several different organic fertilizers, along with a commonly used inorganic slow-release fertilizer (Osmocote). All treatments used a target N concentration of 400 mg/L incorporated into the substrate and we also included fish biosolids treatments of 200 and 800 mg N/L. Plant performance was monitored for 4 weeks starting with commercially available 2-week-old seedlings. The results showed that the 800 mg N/L fish biosolids treatment compared very favorably with the conventional Osmocote treatment at the conclusion of the trial. The 800 mg N/L fish biosolids treatment exceeded the Osmocote treatment for chlorophyll content and for leaf number for the first 3 weeks of the 4-week trial. Grower management protocols could further improve seedling performance by providing additional top dressings of fish biosolids or fish effluent waters as plants age.
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