Chapter 6: Results of using Greywaters on Kikuyu Turf
6.2 Average Daily Growth Rates of Kikuyu (Spring)
The results presented in the following Figure 6.1 to Figure 6.6 cover the 327 days of growth from 16/1/08 to 8/12/08. The results are presented in graphical form as Figures to make it easier to quickly see the growth differences. If required by the reader, the corresponding numerical data in Table form can be obtained by contacting the author. The experiment was ended on 8/12/08 because the samples treated with Water or the greywaters without added urine had been showing poor growth for a long time, probably due to a lack of plant nutrients. The samples with poor growth rates were later used in another short experiment.
6.2.1 Summer: Growth period 16/1/08 to 8/2/08
The results for this growth period are shown in Figure 6.1. From the results it was deduced that the overall pattern of responses reported in the previous Chapter for Tall Fescue also held true for Kikuyu, for this sampling period and across the whole experimental period. That is, relative to water control treatment, shower water and deep rinse water from the washing machine produced equivalent growth or small increases in growth. In comparison total wash treatments sometimes showed somewhat higher levels of growth. Greywater and water to which urine was added showed large increases in growth, sometime higher than the Miracle Gro nutrient addition control. In particular, for this growth period:
Shower produced 80.6% more growth than Water.
SHU produced the largest average daily growth which was respectively 52.8%
and 212% larger than due to the next two highest M/Gro and SHU/5.
The effect of plant food was shown by M/Gro producing 551% more growth than Water which also produced the lowest growth.
The effect of urine was demonstrated by SHU and SHU/5 respectively producing 451% and 76.8% more growth than Shower.
Total wash CPTW produced 32.9% more growth than the deep rinse CPDR.
Result not statistically significant (p = 0.253).
Deep rinse ECDR produced 27.9% more growth than total wash ECTW.
Result not statistically significant (p = 0.401).
The highest average daily growth from greywaters without added urine was due to CPTW.
The phosphate based CPTW averaged 56.6% more growth than the non- phosphate based ECTW. Result not statistically significant (p = 0.116).
Differences between the average daily growth results produced by the six treatments without added urine or plant food i.e. Water, Shower, ECTW, ECDR, CPTW, and CPDR, were not statistically significant (p = 0.090). Statistically significant
differences in growth however resulted between the three treatments which contained added urine or plant food i.e. SHU, SHU/5, and M/Gro (p < 0.001).
Kikuyu (Spring) - 16/1/08 to 8/2/08
0 2 4 6 8 10 12
M/Gro Shower Water ECTW ECDR CPTW SHU CPDR SHU/5
Treatment Average Daily Growth (g/m2 dry weight)
Figure 6.1 – Average Daily Growth (g/m² dry weight) of Kikuyu (Spring) over period 16/1/08 to 8/2/08 (Error bars indicate one standard deviation)
6.2.2 End of Summer: Growth period 6/2/08 to 3/3/08
The results for this 3.5 week growth period are shown in Figure 6.2, and compared to the previous period the average daily growths resulting from SHU and M/Gro
treatments had decreased, whereas growth due to SHU/5 had increased. These results also show that:
Shower produced 62% more growth than Water.
SHU still had the largest growth producing 51% more than SHU/5 and 51.7%
more than M/Gro.
SHU and SHU/5 respectively produced 214% and 108% more growth than Shower.
M/Gro had 236% more growth than Water – which again produced the lowest result.
Total wash CPTW produced 40% more growth than deep rinse CPDR. Result not statistically significant (p = 0.135).
Deep rinse ECDR produced 23.3% more growth than total wash ECTW.
Result not statistically significant (p = 0.347).
Phosphate containing CPTW produced 46.0% more growth than phosphate free ECTW. Result not statistically significant (p = 0.150).
The six treatments Water, Shower, ECTW, ECDR, CPTW, and CPDR again produced average daily growths with differences between them that were not statistically significant (p = 0.104). The three treatments SHU, SHU/5, and M/Gro again produced growth results with statistically significant differences between them (p = 0.001).
However the average daily growth results produced by SHU/5 and M/Gro treatments were similar (p = 0.943).
Kikuyu (Spring) - 6/2/08 to 3/3/08
0 2 4 6 8 10 12
M/Gro Shower Water ECTW ECDR CPTW SHU CPDR SHU/5 Treatment
Average Daily Growth (g/m2 dry weight)
Figure 6.2 – Average Daily Growth (g/m² dry weight) of Kikuyu (Spring) over period 6/2/08 to 3/3/08 (Error bars indicate one standard deviation)
6.2.3 Early Autumn: Growth period 29/2/08 to 16/4/08
During this 6.5 week period all the treatments except SHU/5 produced increased average daily growth, when compared against the previous end of summer period.
The growth results are shown in Figure 6.3 from which it was determined that:
Shower produced 94% more growth than Water.
The largest growth was again due to SHU producing 64.8% more than the next highest M/Gro, and 129% more than the third highest SHU/5.
SHU and SHU/5 respectively produced 147% and a small 8% more growth than Shower.
M/Gro produced 191% more growth than Water which again had the lowest growth.
The largest average daily growth from greywaters without added urine was due to Shower, which was only 1.9% larger than the next highest CPTW.
Total wash CPTW produced 33.1% more growth than deep rinse CPDR.
Result this time was statistically significant (p = 0.001).
Total wash ECTW produced 6.1% more growth than deep rinse ECDR. Result not statistically significant (p = 0.604).
Phosphate containing CPTW produced 8.2% more growth than phosphate free ECTW. Result not statistically significant (p = 0.429).
The five treatments Shower, ECTW, ECDR, CPTW, and the 0.2% v/v urine containing SHU/5 produced average daily growths with differences between them that were not statistically significant (p = 0.138). Inclusion of Water and CPDR growth results with Shower, ECTW, ECDR, and CPTW resulted in statistically significant differences in growth between all six treatments (p = <0.001). The three treatments containing plant food or urine i.e. SHU, SHU/5, and M/Gro, again produced growth results with statistically significant differences between them (p <
0.001).
Kikuyu (Spring) - 29/2/08 to 16/4/08
0 2 4 6 8 10 12
M/Gro Shower Water ECTW ECDR CPTW SHU CPDR SHU/5 Treatment
Average Daily Growth (g/m2 dry weight)
Figure 6.3 – Average Daily Growth (g/m² dry weight) of Kikuyu (Spring) over period 29/2/08 to 16/4/08 (Error bars indicate one standard deviation)
6.2.4 Mid Autumn to Mid Winter: Growth period 11/4/08 to 15/7/08
During this 13.5 week period the average daily growth results produced by all nine treatments reduced significantly compared to the previous early autumn period. The growth results are shown in Figure 6.4, and show that:
Shower produced 145% more growth than Water.
M/Gro now produced the largest growth which was 20.7% more than for SHU, and 169% more than for the third largest SHU/5.
The effect of plant food was still evident with M/Gro producing an average daily growth 695% greater than Water, which continued to produce the smallest growth.
The effect of urine was shown by SHU producing 169% more growth than Shower, and SHU/5 producing 20.4% more growth than Shower. The latter result not statistically significant (p = 0.448).
The largest average daily growth from greywaters without added urine was again due to Shower, which was 21.3% greater than the next largest ECTW.
CPTW produced only 2.5% larger growth than CPDR, and ECTW produced 11.9% more than ECDR. Both results not statistically significant (p = 0.897 and 0.718 respectively).
The phosphate based CPTW produced 14.6% more growth than the non- phosphate based ECTW. Result not statistically significant (p = 0.621).
The six treatments without added urine or plant food i.e. Shower, Water, ECTW, ECDR, CPTW, and CPDR produced average daily growths with differences between them that were not statistically significant (p = 0.179). The three treatments with added urine or plant food i.e. SHU, SHU/5, and M/Gro again produced growth results with statistically significant differences between them (p = 0.014), however the growth difference between SHU and M/Gro was not statistically significant (p = 0.459).
Kikuyu (Spring) - 11/4/08 to 15/7/08
0 2 4 6 8 10 12
M/Gro Shower Water ECTW ECDR CPTW SHU CPDR SHU/5 Treatment
Average Daily Growth (g/m2 dry weight)
Figure 6.4 – Average Daily Growth (g/m² dry weight) of Kikuyu (Spring) over period 11/4/08 to 15/7/08 (Error bars indicate one standard deviation)
6.2.5 Mid Winter to Early Summer: Growth period 14/7/08 to 8/12/08
This growth period of 21 weeks was long because the growth produced by Water was almost non existent, and the growths produced by the greywaters without added urine were very low to enable earlier cutting of these samples. It appeared that the samples receiving treatments that did not contain added urine or plant food were lacking nutrients, and so 1% v/v urine was added to CPTW from 31/7/08 to determine whether growth could be stimulated by the addition of a plant nutrient source. The CPTW with the urine was relabelled as CPTWU (Cold Power Total Wash plus Urine). The samples treated with M/Gro, SHU, SHU/5, and CPTWU grew at a faster rate especially from mid Spring, resulting in the samples receiving these four
treatments having an extra cut from 8/10/08 to 9/10/08. The dry weights of the clippings from the extra cut were included in the collected weights for the whole 21 weeks period.
The average daily growth results over the 21 week period are shown in Figure 6.5, and it was determined that:
Shower produced 288% more growth than Water.
M/Gro and SHU produced almost equal average daily growth, with M/Gro being 0.7% greater (p = 0.967).
The third largest average daily growth was produced by CPTWU which had 162% more growth than the fourth largest SHU/5.
M/Gro produced 3600% more growth than Water which again produced the lowest growth.
The effect of urine was shown by SHU and SHU/5 respectively producing 848% and 148% more growth than Shower.
Total wash ECTW produced 31.8% more growth than deep rinse ECDR.
Result not statistically significant (p = 0.470).
The highest average daily growth from greywaters without added urine was produced by CPDR, which was 19.4% greater than the next highest Shower.
The five treatments Water, Shower, ECTW, ECDR, and CPDR produced average daily growth results with differences between them that were not statistically
significant (p = 0.461). The four treatments with added urine or plant food i.e. SHU, SHU/5, M/Gro, and CPTWU produced growth results with statistically significant differences between them (p < 0.001). However exclusion of SHU/5 (lowest) showed that the growth results due to SHU, M/Gro, and CPTWU did not differ statistically significantly (p = 0.101).
Kikuyu (Spring) - 14/7/08 to 8/12/08
-2 0 2 4 6 8 10 12
M/Gro Shower Water ECTW ECDR CPTWU SHU CPDR SHU/5
Treatment Average Daily Growth (g/m2 dry weight)
Figure 6.5 – Average Daily Growth (g/m² dry weight) of Kikuyu (Spring) over period 14/7/08 to 8/12/08 (Error bars indicate one standard deviation)
Most of the growth occurred towards the end of the 21 week period when the weather got warmer. Figure 6.6 shows the large differences in average daily growth results produced by the four treatments M/Gro, SHU, SHU/5, and CPTWU from before and after the extra cutting session on 8/10/08 to 9/10/08.
Kikuyu (Spring) - 14/7/08 to 9/10/08 and 8/10/08 to 8/12/08
0 2 4 6 8 10 12
M/Gro CPTWU SHU SHU/5 M/Gro CPTWU SHU SHU/5 (14/7/08 to 9/10/08) Treatment (8/10/08 to 8/12/08) Average Daily Growth (g/m2 dry weight)
Figure 6.6 – Average Daily Growth (g/m² dry weight) of Kikuyu (Spring) over the two periods 14/7/08 to 9/10/08 and 8/10/08 to 8/12/08
(Error bars indicate one standard deviation)