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Fluid Journal : Fluid Journal 1993-1995
2 Fluid Journal Summer 1995 Table 2. List of foliar fertilizer treatments in grower/cooperator field triels, Hiller, Washington State University. Treatment No. Foliar Compound Amount/A Timing 1 Leaf Life B 1qt TI,TI+2weeks Leaf Life Mg 1qt TI,TI+2weeks Leaf Life Super Zn 10 1qt TI,TI+2weeks 2 NutraPhos 5 lbs TI Sorba Spray CaB 1 qt TI Sorba Spray Mg 1qt TI NutraPhos 5 lbs TI+2weeks Sorba Spray CaB 1 qt TI+2weeks Sorba Spray Mg 1qt TI+2weeks 3 S&AHighYield 10lbs TI,TI+2weeks S&AHighPhos 10lbs TI+4weeks 4 Leaf Life Mg 2qt TI,TI+2weeks 5 Leaf Life B 2qt TI,TI+2weeks 6 Thio-Sul 1qt TI,TI+2weeks 7 FMCZn 3qt TI,TI+2weeks 8 Sorba Spray Ca 2qt TI,TI+2weeks 9 Sorba Spray CaB 2 qt TI,TI+2weeks 10 Control (water) TI,Ti+2wks,TI+4wks TI = Tuber Initiation Table 2. Average yield increase from foliar applications on potatoes in four- year study (1986 through 1989) in grower/cooperator fields, Hiller, Washington State University. Year Yield Increase Over Check Total No. 1s cwt./A cwt./A 1986 48.0 42.0 1987 9.0 24.6 1988 13.7 16.2 1989 54.0 48.0 4 year aveage 31.2 32.7 categories, specific gravity, and external/internal quality. As shown in Table 3, foliar applica-tions produced "total" yield increases over check that averaged 31.2 cwt./A over four years, and yield increases in "No. 1s" that averaged 32.7 cwt./A over four years. As can be seen, the years 1986 and 1989 produced the best increases during the four years of trials. Results from our trials are encourag-ing and indicate the potential foliar fertilization has in the role of potato pro-duction. Lending further impetus to the new methodology are concerns for ground water quality, cost of fertilizer materials, new formulations available, and new surfactants that promise increased efficiency of foliar absorption. Use care There are a number of factors to con-sider in the application and use of foliar nutrients: Application rate. Too much of certain nutrient elements can cause leaf burn, be wasted, or be toxic. Time of day. For optimum absorption by plants, it is generally recommended that application take place early in the morning or late in the evening. It is further recommended that application not be made during midday, except during cool and cloudy weather. Growth stage. It is generally agreed that these compounds should be applied early in the growing season. However, there is now information to show possible benefits of later applications during the tuber-bulking or tuber-maturing stages. Droplet size. Droplet should be as fine as possible and achieve uniform wetting of leaf surfaces during application. Weather. Apply foliar sprays only when there is adequate soil moisture. Do not apply to plants in a moisture- stressed condition. Balance. Apply only what the plant needs. If there is not a low level on any one nutrient, a balanced formulation would be preferred.
Fluid Journal 1996-1998