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Sulfur Fertilization of Legumes in the Upper Ojai Valley, California, and the Resulting Effects on the Following Nonlegumes
Author(s) -
Conrad John P.,
Hall H. L.,
Chaugule B. A.
Publication year - 1948
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1948.036159950012000c0063x
Subject(s) - officer , agriculture , agricultural extension , miller , political science , management , library science , geography , archaeology , law , biology , economics , computer science , ecology
124.0** T EGUMES, because of the nitrogen fixed by the bacJ_/ teria in the nodules on their roots may, as is well-known, benefit the following nonleguminous crops as some of this fixed nitrogen is released by decay from the legume residues. Nonnitrogenous fertilizers, if they increase the growth of the legumes, may by increasing the amount of nitrogen fixed, further benefit the following nonleguminous crops. An area of Altamont loam in the Upper Ojai Valley of California was worked up dry in the fall of 1940 and seeded to barley before the rains started. Five Vio-acre plots received ammonium sulfate at the rate of 300 pounds per acre. In the late spring of 1941 the volunteer bur clover, largely Medicago hispida, had been so greatly benefited by the ammonium sulfate that it had "choked out" the plantedbarley almost completely. The tentative explanation advanced was that the sulfate part of the ammonium sulfate had corrected a sulfur deficiency for the bur clover which undoubtedly had a much higher sulfur requirement than the planted barley and thereby had enabled the legumes to outyield the nonlegumes. Chemical examination of the ammonium sulfate used failed to disclose any macroor micro-nutrients except nitrogen and sulfur which could account for the great growth of bur clover secured. Thereafter, the area was worked up after the early rains of the fall and winter of 1941 and 1942 and seeded to Hero barley in January, 1942. The plots where the bur clover had grown so luxuriantly the year before stood out markedly during the spring growing period with taller and greener barley plants, but with very few bur clover plants developing. Quadrats from these plots were harvested June 12,1942, threshed, and yields computed. The pertinent data are reported in Table I. These increases, a more than doubling of the yields of threshed grain, may have resulted, in part, from the carry-over of nitrogen from that applied the year before. In general, however, a response of mixed legume and nonlegume plants to nitrogen usually results in an immediate increase in the growth of nonlegumes at the expense of the legumes.