Effect of pH on Zn sorption in untreated and farmyard manure treated alluvial sandy loam soil from a semi-arid region

Deka, A.K.; Poonia, S.R. . Dept. of Soil Science

Effect of pH on Zn sorption in untreated and farmyard manure treated alluvial sandy loam soil from a semi-arid region

2000

Deka, A.K. | Poonia, S.R. (CCS Haryana Agricultural University, Hisar (India). Dept. of Soil Science)

The effect of pH on sorption of Zn in an untreated and corresponding farmyard manure treated fine loamy, Typic Camborthid from a semi-arid region was investigated. The untreated and FYM treated soils were adjusted to three pH levels (i.e high 8; medium 7; low 5) and made homoionic with Ca. The Ca-saturated soil samples were equilibrated with solution having a wide range of Ca:Zn at 10 mmol L -1 total chloride concentration. The pHeq of soil suspensions decreased with the increasing proportion of Zn in equilibrating solutions, the decrease being more pronounced in the high and medium pH samples. At comparable FYM AGo steeply increased with the decrease in soil pH. In the high and medium pH range, AGo for the untreated and FYM treated soil samples were negative (-7.66 & -3.79 kJ mol-l; -0.03 & -0.93 kJ mo1"l). In the medium pH range, the effect ofFYM on AGo was only negligible (i.e. equivalent to 0.9 kJ mol-l). In the low pH range, the values of AGo for the untreated and FYM treated soil samples were positive (6.44 & 4.24 kJ mol-1). The results suggested that thermodynamic preference for Zn over Ca was higher in the high, nearly equal in the medium and low in the low pH range both in FYM treated and untreated soils.

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