Variations in yield and composition of the wheat plant as affected by the time of applying phosphatic fertilizers
1940
Lee, C.K.
Yellow earth, a soil of serious phosphate deficiency, was used in this trial. Pot-culture experiments on the effect of appling a phosphatic fertilizer to wheat gave the following results: 1. Applications of phosphate 30 days after sowing gave the same yield as when the application was made at seeding time. 2. Later applications of phosphate successively caused lower efficiency. The times of ear emergence and ripening were delayed. 3. The concentration of P(2)O(5) in wheat tissue was suddenly increased to about 0.95% after each addition of phosphate. A large excess of phosphate present in the soil did not increase the concentration of phosphoric acid in plants above this figure. 4. Where the phosphate was applied at later stages of growth, more phosphoric acid was retained in the straw. 5. A deficiency of available phosphorus in the soil, not only reduced the yield of wheat, but also diminished the concentration of phosphoric acid in the plant cells. 6. The presence of a small amount of available phosphorus in the soil made later applications of phosphatic fertilizer much more efficient.
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