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Relation of Exchangeable Potassium in Alabama Soils to Needs of the Cotton Crop 1
Author(s) -
Volk N. J.
Publication year - 1942
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/agronj1942.00021962003400020010x
Subject(s) - citation , agricultural experiment station , relation (database) , soil water , chemist , crop , mathematics , agronomy , agriculture , chemistry , environmental science , library science , computer science , geography , archaeology , biology , soil science , database , organic chemistry
p growing in a soil obtain potassium from the soil solution, exchange material, other secondary as well as primary minerals, and organic matter. A great many workers (1, 2, 3, 4, 5, 6, 7)a have investigated or developed methods of extracting and determining the amount of potassium in a soil that may be available to plants. From the data obtained, attempts have been made to show a relationship between the potassium thus extracted from the soil and the need for potassium fertilization. For a number of crops and soils there appears to be a close relationship between yield and exchangeable potassium. Since the equivalent of about 45,ooo tons of muriate of potash is used annually as.a fertilizer in Alabama and since about 70% of this is used for the growing of cotton, a study was undertaken to determine whether any relation exists between exchangeab]e potassium in Alabama soils and the response of cotton to potash fertilization. During the years 1937 to 194o, inclusive, 1~3 cooperative tests were conducted by the Alabama Agricultural Experiment Station4 for the purpose of studying rates of potash fertilization for cotton in certain cropping systems. These tests covered a wide variety of soils and revealed that 94% of the soils responded significantly to the first increment of 25 pounds of potash per acre. The average increase in the yield of seed cotton for this increment was ~95 pounds per acre. On the other hand, only 55% of the soils responded significantly to a second increment of potash, and the average increase in the yield of seed cotton from this was 62 pounds per acre. In another investigation~ involving 283 cooperative tests, it was found that 41% of the soils responded significantly to a second increment of potash (25 pounds of K20 per acre). No information was obtained regarding the response to the first increment of potash since all plots received at least 25 pounds of potash per acre.