Evaluation of the effects of incorporation rate and depth of water-retentive amendment materials in sports turf constructions

Figures & data

Table I. Particle size distribution of the sand used in the experiment.

Category	Particle diameter (mm)	%
Coarse gravel	3.4–8.0	0.0
Fine gravel	2.0–3.4	0.2
Very coarse sand	1.0–2.0	2.1
Coarse sand	0.5–1.0	52.2
Medium sand	0.25–0.5	41.4
Fine sand	0.15–0.25	2.9
Very fine sand	0.053–0.15	0.4
Silt+clay	Less than 0.053	0.9

Table II. Saturated hydraulic conductivity and water retention characteristics (according to ASTM, F 1815-06) of individual mixes used for the experiment (standard deviation values are presented for the saturated hydraulic conductivity values due to more variable nature of this test method).

			Water retention (cm^3 cm^−3) at tensions from − 1.0 to − 6.0 kPa
Treatment	Rate	Saturated hydraulic conductivity (mm hour^−1)	1.0	2.0	3.0	4.0	5.0	6.0
Pure sand	100%	889	0.239	0.179	0.122	0.063	0.044	0.040
Peat	10%	520	0.276	0.271	0.188	0.107	0.084	0.079
	20%	449	0.336	0.329	0.246	0.163	0.139	0.130
	30%	291	0.419	0.407	0.343	0.253	0.224	0.211
Compost	10%	677	0.258	0.248	0.160	0.084	0.065	0.064
	20%	664	0.287	0.275	0.202	0.111	0.088	0.087
	30%	503	0.333	0.316	0.237	0.146	0.121	0.120
Stockosorb	0.5 RR	638	0.264	0.256	0.165	0.089	0.069	0.068
	1.0 RR	615	0.311	0.294	0.207	0.117	0.094	0.092
	1.5 RR	515	0.345	0.328	0.243	0.148	0.113	0.124
TerraCottem	0.5 RR	698	0.239	0.186	0.141	0.073	0.052	0.048
	1.0 RR	646	0.248	0.200	0.148	0.081	0.061	0.056
	1.5 RR	695	0.264	0.204	0.157	0.091	0.069	0.065
Zeolite	10%	800	0.249	0.194	0.131	0.069	0.050	0.046
	20%	808	0.264	0.199	0.130	0.076	0.060	0.058
	30%	855	0.267	0.213	0.154	0.082	0.062	0.058
LSD0.05		63.9	0.0014	0.0032	0.0012	0.0012	0.0015	0.0012

Table III. Water retention (cm³ cm⁻³) at −4 kPa, −1500 kPa (PWP) and available water (AW) of a variety of amendment materials at recommended incorporation rates (standard deviations values are included when only two repetitions were used).

		Water retention
Amendment*	Bulk density (g cm^−3)	−4 kPa	−1500 kPa	AW^†
Pure sand	1.544	0.076	0.014	0.062
Peat	1.278	0.163	0.095	0.068
Compost	1.332	0.111	x^††	x^††
TerraCottem	1.543	0.081	0.013	0.068
Stockosorb	1.394	0.117	0.038	0.079
Zeolite	1.397	0.076	0.048	0.028
LSD0.05	0.055	0.0017	0.006
^†Available water was calculated as the difference between PWP and capillary water content at tension −4 kPa. Different samples were used for both estimations and LSD was not evaluated for AW.
^††Data for the compost have not been presented as there were anomalies with the permanent wilting point value.

Table IV. Volumetric water content (cm³ cm⁻³) in top 60 mm of the profile, measured using a Theta probe as the rootzones mixes drain under gravity with amendments incorporated at recommended rates and in pure sand.

	Time of drainage after saturation (hours)
Amendment	0	1	2	4	8	24	48
Pure sand	21.5	8.1	6.9	6.6	5.9	5.9	5.5
Peat	36.6	15.1	13.7	12.8	12.3	11.6	11.8
Compost	34.7	14.4	12.6	11.5	10.9	10.4	10.1
Terracottem	26.9	10.2	9.0	7.7	7.2	7.5	7.0
Stockosorb	31.4	15.4	13.5	12.6	13.1	12.2	115
Zeolite	23.5	10.4	9.3	8.6	8.1	8.0	7.5
LSD0.05	4.4	3.1	2.7	2.5	3.0	3.2	1.8

Table V. Effect of amendment rate in the lower rootzone layer (150–300 mm) on selected surface properties (values averaged for all amendments and incorporation rates).

	No amendment	50% amendment	100% amendment	LSD0.05
Volumetric water content 0–60 mm (%)*	9.1	9.5	9.7	1.2
Hardness (gravities)	53.1	51.8	52.7	5.8
Shear strength (kPa)	6.03	6.08	5.79	0.85
*VWC was measured by Theta probe after 48 hours drainage.

Figure 1.  The differences in shear strength among used materials (pure sand = 5.0 kPa = 100); vertical bars show the confidence limits at p=0.05.

Figure 2.  The differences in hardness among the used materials (pure sand = 59 gravities = 100%); Vertical bars show the confidence limits at p=0.05.

Figure 3.  Effect of amendment materials and incorporation rate on water retention (mm) in the upper layer of rootzone (0–150 mm), vertical lines show the confidence limits at p=0.05; water retention of pure sand layer was 14.6±s.d. 0.46. For Stockosorb and TerraCottem rate 10 means 0.5 recommended rate (RR), rate 20 = 1.0 RR and rate 30 = 1.5 RR.

Table VI. Effect of amendment materials and incorporation rate on water retention (mm) in the lower layer of rootzone (150–300 mm); water retention of pure sand layer was 41.3±0.6 mm. For Stockosorb and TerraCottem rate 5 means 0.25 recommended rate (RR), 10 = 0.5 RR, 15 = 0.75 RR, 20 = 1.0 RR and rate 30 = 1.5 RR.

	Amendment rate (v/v%)
Amendment	0	5	10	15	20	30	Overall mean	LSD0.05
Peat	41	42	44	46	49	57	47	0.95
Compost	41	41	41	42	46	48	43
Stockosorb	41	43	44	47	48	55	46
TerraCottem	41	40	41	42	44	44	42
Zeolite	41	41	44	46	46	49	44
Overall mean	41	42	43	45	47	50	44
LSD0.05	0.96

Table VII. Analysis of variance results for water retention influenced by amendment materials and different rate in lower layer (data are related to Figure 3 and Table VI).

	Upper layer (0–150 mm)			Lower layer (150–300 mm)
Source of variation	df	MS	p	df	MS	p
Amendment	4	209.04	0.000	4	73.9	0.000
Rate in lower layer	2	222.05	0.000	5	187.5	0.000
Amendment*rate in lower layer	8	20.15	0.044	20	11.2	0.000
Error	30	8.63		60	2.0

Table VIII. Effect of amendment rate in lower rootzone on water retention in (a) the upper profile and (b) through the whole profile. The figures represent mean values for different amendment rates in the upper 150 mm.

Rate of amendment in lower rootzone	Pure sand	Peat	Compost	Stocko-sorb	Terra-Cottem	Zeolite	Overall mean	LSD0.05
Total water held (mm) in upper 150 mm
No amendment		27	23	26	17	18	22	5.9
Half rate of upper profile		28	24	28	16	19	23
Full rate of upper profile		30	24	27	16	19	23
Overall mean	14	28	24	27	16	19	23
LSD0.05
Total water (mm) held in full profile (0–300 mm)
No amendment		68	64	67	57	60	63	8.4
Half rate of upper profile		72	66	73	57	63	66
Full rate of upper profile		80	69	76	59	65	70
Overall mean	56	73	66	72	58	63	66
LSD0.05		8.5

Table IX. Analysis of variance results for amendment materials and different rate in lower layer (data are related to Table VIII).

	Upper layer (0–150 mm)			Whole rootzone (0–300 mm)
Source of variation	df	MS	p	df	MS	p
Amendment	4	701.5	0.000	4	1097.2	0.000
Rate in lower layer	2	16.6	0.463	2	530.5	0.000
Amendment*rate in lower layer	8	4.9	0.985	8	36.3	0.574
Error	120	21.5		120	43.5