TITLE:
A Brief Study on Using pHH2O to Predict pHKCl for Acid Soils
AUTHORS:
Anqi Wang, Decheng Li, Biao Huang, Yin Lu
KEYWORDS:
Predicting Model, pHKCl, pHH2O, Correlation, Influential Factors, Acid Soil
JOURNAL NAME:
Agricultural Sciences,
Vol.10 No.2,
February
21,
2019
ABSTRACT: pHKCl and pHH2O are two basic necessary indexes to reflect the acidity of asoil. Predicting pHKCldirectly from pHH2Ocould save the cost of laboratory work. In this study, the values of pHKCl and of 442 and 310 horizon samples from 126 and 98 soil profiles (0 - 120 cm in depth) surveyed from 2014 to 2015 in Guangxi and Yunnan were used to establish the optimal correlation model between pHKCl and pHH2O. The results showed that: 1) pHKCl is lower than pHH2O, pHKClwas 0.07 - 1.99 units with a mean of 0.99 units lower than for Guangxi, while 0.03 - 1.90 units with a mean of 0.89 lower than pHH2Ofor Yunan. 2) There is significant positive correlation between pHKCland pHH2O, the optimal correlation models between pHKCl(y) and pHH2O(x) for Guangxi and Yunnan are y = 0.1963x2 − 1.0512x + 4.338, R2 = 0.836, p 0.1859x, R2 = 0.769, p pHKClwith exchangeable H+ and Al3+ (R2 = 0.487, 0.716, p pHKClis dominated by exchangeable Al3+, followed by exchangeable H+, and their contribution to pHKClwere 71.1% and 28.7%, respectively.