• Korean Journal of Soil Science and Fertilizer
• /
• v.21 no.2
• /
• pp.195-201
• /
• 1988

A laboratory experiment was coducted to investigate the relation of various soil phosphorus and some soil chemical properties which affect the composition of inoganic phosphorus and soil phosphorus with 149 phosphorus accumulated soil samples. Soil pH and exchangeable Ca were showed positively high significant correlation with 1.25 $N-NH_4$ OAc-P, Saloid-P, Ca-P and Total-P, however the soil pH was not showed significant relationship with $0.01M-CaCl_2-P$, Al-P, and Fe-P, respectively. Active Al and available phosphorus, water soluble P, and inoganic phosphorus were showed negatively high significant correlation, but Al-P and Fe-P were not. Also active Fe were showed positively significant correlation at 1% level for Fe-P and total-P. In the relationahips between soil pH and active Al, and exchangeable Ca, active Al were showed negatively high significant correlation with log regression equation, and exchangeable Ca were showed positively high significant correlation with liner regression equation. P sorbed by soil from p 20ppm solution was showed negatively high significant correlation with available phosphorus, water soluble P and $0.01M-CaCl_2-P$ in soil and positively with active Al, but was not significant with Ca-P.

• Korean Journal of Soil Science and Fertilizer
• /
• v.16 no.1
• /
• pp.42-49
• /
• 1983

In order to find out the possibility of predicting fertilizer K requirement from the K supplying capacity of soil, the relative K activity ratio, Kas/kai, the potential buffering capacity of $K^+$ ($PBC^k$ ; the liner regression coefficient) and its activity ratio ($AR^k_o$ ; $^{k+}$/${\sqrt{Ca^{+2}+Mg^{+2}}}$ in mol/l) at ${\delta}K$ = O, in the Q/I relationships of Beckett(1964), were determined for the soils before flooding and the samples taken at heading stage of transplanted rice in pot experiment. These parameters assumed as the K supplying capacity of soils were subjected for the investigation through correlation stady between themselves and other factors such as grain yield or the amounts of $K_2O$ uptake by rice plant at harvest. The results may be summarized as follows; 1. The potassium supplying power of the flooded soil was considered to be ruled by the amounts of exchangeable K before flooding, since there was little change in exchangeable K concentration from no-exchangeable K during the incubation periods of 67 days. 2. The $PBC^k$ values, in soils before flooding were 0.027, 0.014 and 0.009, where as the $AR^k_o{\times}10^{-3}$ values were 9.1, 7.6, and 15.4, respectively, in clay, loamy and sandy loam soils. 3. The $PBC^k$ values, determined in the soil samples taken at heading stage, varied little compared with the values of orignal soil, regardless of those different fertilizer treatments and textures, showing the possibility of using them as a factor for the improvement of soil to increase the efficiency of fertilizer K. 4. The significant yield responses to potassium fertilizer application were observed wherever the $AR^k_o$ values in soil at heading stage drop down to the original $AR^k_o$ values, regardless of any levels of fertilizer application. 5. The higher correlations between the gain yield or the amounts of $K_2O$ uptake and by the use of both soil factors of $PBC^k$ and $AR^k_o$ at heading stage were observed compared with the use of any single factor. 6. The Kas/Kai value in the soil, estimated prior to the experiment, had high possitive correlation with the $AR^k_o$ determined in the soil at heading stage and could be used as a soil factor for predicting potassium fertilizer requirement.