Table 6: Effect of sewage sludge and stabilized sewage sludge on the DTPA-extractable zinc in relation to soil type, sewage source, mixing rate, and incubation period.

TreatmentsFluvial soilCalcareous soil
SS1SS2SS1SS2
30 day60 day30 day60 day30 day60 day30 day60 day

Mixing rate, 10%

C1.21f1.20e1.21d1.20e2.18e2.16e2.18f2.16e
SS8.46ab8.11a9.57a7.80b10.50a8.84a10.10a9.15a
SS + CFA7.77bcd6.40c7.46bc6.39cd9.02b6.51cd9.46bc7.79b
SS + B7.49cde7.36ab7.56bc7.46b6.24a7.13bc8.63d7.60bc
SS + SBFL8.15abc6.49c7.59bc6.68cd7.57c8.10a8.78d7.81b
SS + CaCO37.19de6.63bc7.57bc6.85c7.76c7.32b8.89cd6.72cd
SS + WH7.15de6.18c7.37c6.07d7.22c6.69bcd6.87e6.49d
SS + RS6.78e5.35d8.14b7.72b7.54c6.01d9.04bcd7.96b
SS + CS8.89a7.33ab7.85bc8.60a8.62b8.19a9.66ab9.70a

Mixing rate, 25%

C1.21c1.20e1.21e1.20f2.18e2.16f2.18d2.16 g
SS8.46a8.11a9.57a7.80a10.5a8.84b10.10a9.15a
SS + CFA7.24ab5.77cd7.50bc7.14bc8.36bc7.24d7.92bc7.39de
SS + B6.86ab5.64cd7.28c7.31b7.72bcd7.99c8.75b7.87bcd
SS + SBFL7.33ab6.70b8.00b7.34b7.12cd8.22c7.98bc7.54cde
SS + CaCO36.12b8.00a7.37bc6.28d8.17bc7.34d8.64b6.00f
SS + WH6.66b6.29bc5.99d5.80e6.52d5.73e7.20c6.90e
SS + RS6.66b4.83d9.17a7.49ab7.17cd6.25e9.74a8.33abc
SS + CS7.56ab7.88a8.92a6.88c8.71b9.64a9.95a8.73ab

Values accompanied by different letters are significantly different within column ( ).