Influence of Stabilized Biosolids Application on Availability of Phosphorus, Copper, and Zinc

Table 7

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

Treatments	Fluvial soil				Calcareous soil
	SS1		SS2		SS1		SS2
	30 day	60 day	30 day	60 day	30 day	60 day	30 day	60 day
Mixing rate, 10%
C	3.86^d	3.88^d	3.86^d	3.88^b	3.11^d	3.10^d	3.11^b	3.10^a
SS	7.01^a	6.98^a	6.95^a	6.90^a	6.17^a	4.68^a	4.39^a	3.64^a
SS + CFA	6.70^a	6.03^b	6.62^ab	6.62^a	4.11^c	3.19^d	3.39^b	3.29^a
SS + B	6.22^b	6.85^a	6.21^bc	5.98^a	2.88^e	3.57^cd	3.36^b	2.77^a
SS + SBFL	6.40^ab	6.80^a	6.90^ab	6.55^a	3.66^c	3.88^bc	4.25^a	3.62^a
SS + CaCO3	6.99^a	6.94^a	6.80^ab	6.30^a	3.96^c	4.35^ab	4.32^a	3.36^a
SS + WH	6.73^a	5.79^b	5.88^c	4.20^b	3.81^c	3.33^d	3.12^b	3.18^a
SS + RS	5.27^c	4.63^c	6.55^ab	6.89^a	3.89^c	3.36^d	4.34^a	3.55^a
SS + CS	6.69^a	6.95^a	6.71^ab	5.97^a	4.87^b	3.33^d	4.12^a	3.39^a
Mixing rate, 25%
C	3.86^c	3.88^e	3.86^d	3.88^e	3.11^d	3.10^cd	3.11^c	3.10^bc
SS	7.01^ab	6.98^a	6.95^ab	6.90^a	6.17^a	4.68^a	4.39^a	3.64^a
SS + CFA	6.46^ab	5.18^cd	5.92^c	5.53^b	3.26^d	2.88^d	2.63^d	2.97^cd
SS + B	5.80^ab	5.59^bcd	5.72^c	5.25^bc	3.27^d	3.39^bc	3.88^b	2.62^d
SS + SBFL	6.37^ab	6.50^ab	6.89^ab	6.59^a	3.52^cd	3.60^b	3.78^b	3.50^a
SS + CaCO3	7.21^a	7.11^a	7.28^a	6.77^a	4.05^bc	4.59^a	4.47^a	3.44^ab
SS + WH	6.40^ab	5.98^abc	6.00^bc	4.02^de	3.54^cd	2.81^d	2.75^cd	2.99^cd
SS + RS	5.22^bc	4.59^de	6.51^abc	6.64^a	3.67^bcd	2.70^d	3.85^b	2.74^cd
SS + CS	6.31^ab	6.39^ab	6.12^bc	4.73^cd	4.32^b	3.67^b	4.19^ab	2.84^cd

Values accompanied by different letters are significantly different within column (𝑃<0.05).