Crop Response to Excessive Zinc Fertilization of Alkaline Soil1
- Louis C. Boawn and
- P. E. Rasmussen2
The objective of this research was to evaluate the tolerance of economic plant species to excessive levels of available Zn in the soil.
Fifteen field crop and three vegetable crop species were grown under uniform conditions in a growth chamber in alkaline soil treated with 10, 100, 200, 300, 400, and 500 ppm Zn. Response was evaluated in terms of dry matter yield decrease (YD) and Zn concentration in tops. Grass species were most sensitive and had maximum YD's greater than 40%. Alfalfa (Medicago saliva L.), Alaska pea (Pisuni sativum L.), tomato (Lycopersicon esculentum Mill.), lettuce (Latuca saliva L.), spinach (Spinacia oleracea), and sugarbeet (Beta vulgaris L.) had YD's between 20 and 40%. Field bean (Phaseolus vulgaris L.), snap bean, russet potato (Solanum tuberosum L.), white potato, clover (Trifolium repens L.), and Perfection pea (Pisum sativum L.) did not undergo a significant YD.
Zinc concentrations in tops associated with a 20% YD ranged from 240 ppm for field bean to 740 ppm for sugarbeet, with most crops falling in a 400 to 600-ppm range. The most sensitive species tolerated Zn additions of 200 to 300 ppm before undergoing a significant YD.
Crops that underwent a significant YD because of excess Zn were stunted but showed no discoloration, malformation, or necrosis indicative of a direct metal toxicity.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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