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Fluid Journal : Fluid Journal 1993-1995
1 Fluid Journal Summer 1995 Table 1. Macro and micro nutrient elements required for plant growth and metabolic processes in plants, Hiller, Washington State University. MACRO MICRO Nitrogen Boron Phosphorus Copper Potassium Iron Calcium Manganese Magnesium Molybdenum Sulfur Zinc Summary: Results from these research trials would indicate that foliar fertilization has potential for an important role in potato production. Several new consider-ations, such as cost of fertilizer materials, concern for ground water quality, availability of new formulations of com-pounds, newer surfactants that increase efficiency of foliar absorption, etc., arc factors that give reason to consider this fertilization method. Foliar fertilizer materials can be one more tool, along with soil-applied fertilizers, soil tests, and petiole analyses, to fine-tune fertility programs to maximize both quantity and quality of potatoes produced. One of the first questions pertain ing to the use of foliar fertiliza tion is: can fertilizer nutrients be absorbed through leaves and stems? It has been established in various research studies that plant leaves and other above-ground parts are capable of absorbing chemicals and nutrients. Absorption of nutrients by plants is not a function limited to the root system. In recent years, there has been renewed interest in the use of foliar fertilizers on potatoes and other crops. The renewed interest is largely due to the availability of new fertilizer formulations, which appear to be more suitable when used in this manner. Applying macro and micro nutrients to the foliage of plants is not a new practice. It has been used on commercial fruit and vegetable crops for more than fifty years. However, there is limited research information on the commercial application and use of foliar nutrients on potatoes. Dr. Larry K. Hiller Foliar Fertilization Bumps Potato Yields in Northwest Rate and timing of application, plus host of other considerations, are critical in applying foliars to potatoes. All of the macro and micro plant nutrient elements that contribute to plant growth and development, as well as the functional and metabolic processes that go on in plants, are listed in Table I. A deficiency of any one element will adversely affect and limit the entire metabolic system. On the other hand, toxicity levels and antagonistic relation-ships of nutrient elements can also occur in plants and cause detrimental results. This article will present results of some of our research, the general aspects of foliar fertilization, and factors affecting uptake as well as use of foliar nutrients. Setup Objectives of our field trials have been to: • evaluate the effect of foliar macro and micro nutrient applications on tuber yield (external and internal quality) • determine effect on growth and various physiological parameters in potato • evaluate interactions of plant/soil/ water levels and foliar treatments. Foliar nutrient applications were evaluated for four years on commercial potato fields in the Pasco, Warden, and Quincy areas of the Columbia Basin. These general evaluation trials were located on grower fields for actual com-mercial conditions under center pivot irrigation systems. Cultural, fertilization, and manage-ment practices were those normally used by each grower, except for foliar spray applications in our plots. Thus, these treatments were in addition to the grower's planned fertilization program. Sprays were applied at the rate of 20 gal/A, or at label rate if specifically stat-ed otherwise. Plots consisted of paired rows 40 feet long, with a guard row on each side. Treatments were arranged in a ran-domized complete block design with six replications for statistical analyses. Russet Burbank was the cultivar used in all trials. Foliars prove worth Table 2 shows the commercially available foliar compounds that were tested and compared with an untreated control each year. The table also indicates the rate and time of application of the foliar sprays. Materials were selected to provide either a fairly complete application of most of the nutrient elements, or single elements. The usual harvest data were obtained in all trials including total yield, and yield of No. 1s and 2s in various size
Fluid Journal 1996-1998