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Effect of Ammonium‐Nitrate on the Defoliation of Immature Cotton Leaves
Author(s) -
Gausman H. W.,
Cowley W. R.
Publication year - 1954
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1954.00021962004600030011x
Subject(s) - ammonium nitrate , citation , horticulture , mathematics , biology , computer science , library science , chemistry , organic chemistry
HIS note is concerned with leaf defoliation of immaT ture cotton resulting from side-dressing treatments with ammonium nitrate. The results mentioned herein may be indicative of the need for more basic research regarding aspects of nitrogen metabolism on the chemical defoliztion of mature cotton leaves. The defoliation of the immature leaves occurred in an experiment designed to study the effects of differential \fertilizer ,treatments on the chemical defoliation of mature cotton. This investigation consisted 'of a 3 2 factorial fertilizer t9est in quintuplicate. The cotton variety, Deltapine TPSA, was used and plantings were made in five gallon crocks. Initial applications of fertilizers at equivalent rates in pounds per acre were: elemental nitrogen (N), 0, 50 and 100 fr0.m 33.5% ammonium nitrate and phosphoric acid (P,05), 0, 100 and 200 from 45% superphosphate. The fertilizers were spot-placed two inches below and two inches to the side of the cotton seed. The cotton originally treated with N received an additional supply of 50 or 100 pounds of spot-placed N as a side-dressing treatment at the time of squaring. The cotton was given approximately equal amounts of water directly after the side-dressing treatment. Eight hours after the side-dressing treatment with N, wilting and interveinal yellowing occurred on plants in three replications which had received a total application of 100 and 200 pounds of N without the addition of P,O, (figure 1). Microscopic examinations of lfresh tissue from injured portions of the leaves indicated that the palisade layer of cells had collaps'ed 'but the mesophyll tissue appeared to be intact. Two days subsequent to the sidedressing treatment, defoliation of the older leaves occurred after the formation of an abscission layer. The affected plants later recovered and p roduced rapid vege ta t ive regrowth.