Different Rates Of Fertilizer Research Articles

Equipment for Application of Fertilizer at a Linear Increase Rate1

AbstractConventional procedure for evaluating effects of different rates of fertilizer on crop response requires a series of plots, each receiving a different rate. This technique uses a lot of land and requires much time and labor. Thus an experimental planter that delivers fertilizer in continuously increasing rates ranging from zero to the maximum rate desired was designed and constructed. A previously weighed sample of fertilizer is distributed, at uniform depth, in a V‐shaped mold which is placed on top of the rubber belt of a conventional belt fertilizer applicator. The mold is removed and the plot is planted. Gears adjust the rate of travel of the belt so that there is a continuously increasing rate of application from the beginning of the plot, at the front of the belt, to the maximum rate, at the end of the belt where the fertilizer band on the belt is the widest. The equipment performed very satisfactorily for snap beans (Phaseolus vulgaris L.) and sweet corn (Zea mays L.) in 1975.

The Relationship of Granny Smith Apple Tree Growth and Early Cropping to Planting Density and Rectangularity

SummaryAn apple tree planting density experiment with an expanding grid design indicated that production per tree, during the first three years of bearing, was greatest at moderate spacings (450-500 trees per hectare); trees planted very close together (up to 1,637 per hectare) produced less fruit per tree, and per unit of tree volume, but more per hectare. Trees at maximum spacings (250-300 per hectare) were less efficient and showed the adverse effects of exposure. Rectangular as opposed to square planting of these vase-shaped trees improved accessibility, but reduced the weight of fruit harvested per hectare and per tree. Leaf nutrient levels appeared to be similar at all spacings and did not reflect the different rates of fertilizer applied per tree.

Fertilizer Evaluation: II. Estimation of Availability Coefficients

AbstractResponse curves produced when plants are grown on soils treated with different rates of fertilizers are used as the basis for estimating the ratio of the availability coefficient of a nutrient in one fertilizer to that in another. A least squares method is described and illustrated for fitting each of three types of response curves. Concurrent linear response curves are illustrated by data on yield of phosphorus. Parallel linear response curves for log response against log rate of application are illustrated by data on content of radioactive phosphorus. Concurrent Mitscherlich curves with the same initial and limiting responses but different rates of increase are illustrated by data on yield of corn grain.

Eight Years of Experimental Work in Boll Weevil Control on Plots Receiving Different Rates of Fertilizer

Calcium arsenate controlled the boll weevil ( Anthonomus grandis Boh.) on one-twentieth-acre plots over an eight-year period. Infestation counts were made bi-weekly and calcium arsenate was applied when the infestation reached or exceeded ten per cent. All applications were made during the day time when the air was relatively calm.