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The Correlation of Soil Phosphorus with the Yields of Ladino Clover
Author(s) -
Welch L. F.,
Ensminger L. E.,
Wilson C. M.
Publication year - 1957
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/sssaj1957.03615995002100060012x
Subject(s) - loam , phosphorus , yield (engineering) , soil type , soil series , soil test , mathematics , agronomy , soil water , soil fertility , soil classification , chemistry , environmental science , soil science , biology , materials science , organic chemistry , metallurgy
Ladino clover ( Trifolium repens ) was grown in 11‐ by 6‐foot concrete‐walled field bins that contained three soil types representing large acreages in Alabama, namely Norfolk sandy loam, Eutaw clay, and Cecil clay. Soil samples were taken from the bins prior to seeding the clover and were extracted for soluble phosphorus by three extracting solutions. The solutions used were 0.05 N HCl + 0.025 N H 2 SO 4 , 0.5 M NaHCO 3 , and 0.03 N NH 4 F + 0.1 N HCl. The procedure used with each solution can readily be adapted for rapid, relatively inexpensive tests as is required of a method to be used in a soil testing laboratory. The study consisted of 40 bins of each soil type, and because of past phosphorus treatments within a soil type, the bins differed greatly with respect to the amounts of soluble phosphorus present. Six harvests were taken from the bins, three each in 1954 and 1955. The following correlations were made: relative yields for 1954 with soil test P 2 O 5 values as determined by each solution on each soil type, relative yields for 1955 with soil test P 2 O 5 values, and P 2 O 5 values for one solution with values for another solution on a given soil type. All correlation coefficients were highly significant. Regressions equations were calculated for the regression of soil test P 2 O 5 values on 1954 relative yield, 1955 relative yield, and total relative yield. Classes of soil test P 2 O 5 values were calculated from the regression equations on the basis of the amount of P 2 O 5 , as indicated by soil tests, required to give a specified relative yield. Data presented show that either of the three soil testing methods can be used satisfactorily as a basis for making phosphorus recommendations for the soils and crop studied. No one solution proved to be statistically better than the other two. All solutions tended to give higher correlation coefficients for the Eutaw and Cecil soils rather than for the Norfolk.