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Yield Response in Experiments With Phosphorus Fertilizers in Relation to: II. Variability and Differences Among Sources on Soils of Northern and Western States
Author(s) -
Terman G. L.
Publication year - 1961
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/sssaj1961.03615995002500010023x
Subject(s) - yield (engineering) , phosphorus , limiting , soil water , mathematics , grain yield , coefficient of variation , agronomy , statistics , environmental science , zoology , soil science , chemistry , biology , materials science , mechanical engineering , organic chemistry , engineering , metallurgy
Yield results from 124 experiments in Colorado, Iowa, New York, and Washington comparing phosphorus rates and sources, each including a response curve with CSP, were summarized in regard to the nature of the response and experimental error. In less than 10% of the tests with corn, small grain, and vegetables showing response to P was it possible to measure differences among sources from one‐half to twice as effective as CSP. Although experimental error was important, low response to applied P was the chief factor limiting the measurement of differences among sources. Coefficient of variation (CV) decreased with increase in mean yield of corn experiments in Iowa. Numerical increases in yields resulting from applied P were about the same at all yield levels in these experiments.