| УДК |
Аннотация: A study was made of the actual rates and distribution patterns of aerially applied urea fetilizer using norminal rates of 50 and 100 lb./ac. nitrogen. It was concluded that: 1. The variation in distribution at the 50 lb./ac. N rate was great enough to render such application unsuitable. 2. The amount of fertilizer monitored falling through the tree canopy (jack pine, Pinus banksiana Lamb.) was similar to that monitored in open strips. 3. At nominal rates of 100 lb./ac. N, monitoring catchers of 1 square foot area were as suitable as those of 2 square feet area. 4. The estimated numbers of monitoring catchers needed to measure urea fertilizer at 100 lb./ac. N rate was determined for various assumed levels of accuracy. 5. It was suggested that narrow rectangular monitoring plots using 10 catchers each be used to determine fertilizer distribution and tree growth plot locations. 6. Growth responses to fertilizer treatments are more realistic when related to both a response curve and the area distribution of fertilizer. A system of monitoring catchers and plots is recommended which will enable this to be accomplished. 7. The use of cacodylic acid to kill trees in lines, so that the dead red brown foliage would provide marker lines for the aircraft feasible. It should be noted that although jack pine (Pinus banksiana Lamb.) and balsam fir (Abies balsamea (L.) Mill.) retain their dead foliage for a year or more, the foliage of spruces Picea falls after the tree's death.
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