Evaluation of Laboratory Tests on Organic Soils for Prediction of Phosphorus Availability1
- Henryk Okruszko,
- G. E. Wilcox and
- G. F. Warren2
Nineteen muck and peat soils from northern Indiana were subjected to different laboratory analyses in an effort to determine what criterion might allow prediction of percentage yield that would be obtained with respect to P fertilization. Percentage yield of ladino clover was related to log of P in extracts of 0.5N HCl, 0.002N H2SO4, 0.5N acetic acid, and H2O in the order r = 0.867, 0.732, 0.786, and 0.887, respectively.
The use of ratios of cations to P in the HCl extract increased the r values for the relationship between yields and predictive factors to r = -0.919 for the Fe + Al/P ratio and yield relationship.
When P in HCl extract, P in H2SO4 extract, Ca/P ratio, and Fe/P ratio in HCl extract were combined in their relationship to percentage yield, R = 0.948 was obtained. From the data obtained a table was set up with cation/P ratios corresponding to P fertility level of muck soil.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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