Biocides, Fertilizers, and Survival Potential of Tree Planting Stock
During the last decade forest nursery practice has accepted wide use of organic eradicants, such as Trizone, Vapam, Mylone, Vorlex, and Dacthal. Some of these chemicals induce highly undesirable changes in morpho-anatomical and physiological properties of nursery stock. The most important of these are as follows: Abnormal stimulation of top growth; high increase in succulence of plants with subsequent reduction of specific gravity of lignified parts of seedlings; reduction of root systems, their lengths, and absorbing surface. Largely these unfavorable modifications result from a discrepancy in the nitrogen-phosphorus nutrition of plants. Organic biocides unduly increase the supply of available nitrogen by elimination of microbiotic consumers of nitrates and ammonia, and by enrichment of the root zone in proteinaceous tissues of controlled organisms (Iyer 1964). On the other hand, eradication of mycorrhiza-forming fungi greatly retards uptake of phosphorus by seedlings even when this element is abundant in the soil in so-called "available form" (Henderson and Stone 1967; Lipas 1968).
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Author(s): Jaya G. Iyer
Publication: Tree Planters' Notes - Volume 21, Number 3 (1970)
Volume: 21
Number: 3