A positive valorization way of sludge compost: recycling it to turfgrass instead of partial conventional substrate

Figures & data

Table 1. Main physico-chemical property of the sludge compost and conventional turfgrass substrate.

Indicator	Sludge compost	Conventional turfgrass substrate
Organic matter (%)	28.0	5.6
Total nitrogen content (%)	4.6	1.8
Total phosphorus content (%)	2.7	1.1
Total potassium content (%)	1.9	0.6
Moisture (%)	48.5	36.6
Maturity (%)	88	–
Total porosity (%)	0.61	0.55
Water-holding porosity (%)	0.46	0.42
Electrical conductibility (mS/cm)	0.45	0.26
Bulk density (g/cm^3)	0.95	1.01

Table 2. Effect of amendment of sludge compost to turfgrass on physical properties of substrate at different doses.

Dose of composted sludge added to substrate (Mg/ha)	Bulk density (g/cm^3)	EC (mS/cm)	Total porosity (%)	Water-holding porosity (%)
120	0.94 ± 0.07 a	0.29 ± 0.23 a	0.63 ± 0.03 a	0.49 ± 0.02 a
90	0.96 ± 0.04 a	0.27 ± 0.13 ab	0.63 ± 0.02 a	0.48 ± 0.06 a
60	0.95 ± 0.03 a	0.22 ± 0.08 b	0.65 ± 0.03 a	0.46 ± 0.02 a
30	0.98 ± 0.05 ab	0.23 ± 0.06 b	0.64 ± 0.04 a	0.43 ± 0.03 ab
Conventional substrate	1.01 ± 0.02 b	0.23 ± 0.03 b	0.64 ± 0.02 a	0.39 ± 0.03 b

Table 3. Effect of addition of sludge compost instead of partial substrate on biomass indicators of turfgrass at different doses.

Dose of composted sludge added to substrate (Mg/ha)	Fresh weight per seedling (g)	Plant height (cm)	Root length (cm)	Tiller number (piece)
120	5.51 ± 0.42 a	7.98 ± 0.35 a	7.86 ± 0.49 a	6.3 ± 0.9 a
90	5.22 ± 0.36 b	7.67 ± 0.28 b	7.42 ± 0.59 b	5.8 ± 1.1 ab
60	5.08 ± 0.28 c	7.58 ± 0.52 b	7.55 ± 0.35 ab	4.7 ± 1.2 b
30	5.03 ± 0.38 c	7.52 ± 0.31 b	7.18 ± 0.27 c	4.5 ± 1.2 b
Conventional substrate	5.42 ± 0.31 ab	7.87 ± 0.24 a	7.84 ± 0.36 a	5.1 ± 1.8 ab

Table 4. Effect of amendment with different doses of sludge compost in place of substrate on turfgrass establishment.

Dose of composted sludge added to substrate (Mg/ha)	Leaf width (cm)	Chlorophyll content (mg/g)	Concomitant weed density (seedling/m^2)	Establishment time (day)
120	0.38 ± 0.05 a	1.13 ± 0.06 a	283.5 ± 15.8 a	67.7 ± 2.4 a
90	0.35 ± 0.02 ab	1.15 ± 0.06 a	262.4 ± 10.5 ab	63.5 ± 3.6 ab
60	0.32 ± 0.03 abc	1.11 ± 0.07 ab	234.8 ± 12.4 bc	61.6 ± 3.2 bc
30	0.30 ± 0.05 bc	1.08 ± 0.05 ab	228.2 ± 18.9 c	60.8 ± 4.1 bc
Conventional substrate	0.29 ± 0.04 c	1.04 ± 0.04 b	163.9 ± 21.4 d	58.2 ± 2.1 c

Table 5. Effect of amendment with different doses of sludge compost on sod product related profiles.

Dose of composted sludge added to substrate (Mg/ha)	Sod weight (kg)	Sod tensile strength (N)	Sod intactness (%)
120	10.7 ± 0.4 a	15.7 ± 3.4 a	86.8 ± 0.5 a
90	11.2 ± 0.6 ab	19.6 ± 2.6 ab	88.5 ± 0.6 b
60	11.7 ± 0.5 b	22.7 ± 3.5 bc	88.8 ± 0.7 b
30	12.4 ± 0.4 bc	24.6 ± 1.7 c	89.2 ± 0.5 b
Conventional substrate	13.2 ± 0.6 c	26.5 ± 2.2 c	91.2 ± 0.4 c

Table 6. Effect of amendment with different doses of sludge compost on turfgrass transplanting related indicators.

Dose of composted sludge amendment to substrate (Mg/ha)	Greening maintaining period (day)	Root regeneration ability (cm)	Proportion of greening recovery in coming year (%)
120	163.8 ± 1.8 a	9.05 ± 0.84 a	56.4 ± 5.6 a
90	161.3 ± 2.2 a	8.29 ± 0.63 ab	52.2 ± 9.6 ab
60	153.7 ± 2.8 b	7.93 ± 0.42 b	49.4 ± 5.7 ab
30	156.4 ± 3.2 b	7.62 ± 0.56 b	41.8 ± 6.5 c
Conventional substrate	154.5 ± 1.8 b	7.87 ± 0.89 b	50.9 ± 7.4 b