Chapter 4: Greywater experiments on two types of turf – Experimental Methods… …
4.3 Watering of the turf samples …
Initially sub-surface watering was attempted by using four plastic watering spikes to which plastic funnels, which were cut from the tops of soft drink bottles, were
attached. Experiments with just sandy loam soil in a pot, showed that one spike in the centre was not sufficient to adequately water the soil out towards the edges. However the use of four watering spikes placed about 70 mm in from each corner watered the soil satisfactorily, although the setup with attached funnels tended to selectively block the sunlight. Replacement and removal of the spike setup for each watering session enlarged the holes in the soil, and so the greywater tended to break on to the surface.
The procedure also took far too long to water all the plants. Seeing that the greywater tended to break on to the surface, it was decided to just sprinkle the greywater directly on to the plants. A sprinkling cup was constructed by drilling holes into the base of a 600 ml plastic cup. Usually 300 ml of greywater was tossed into the sprinkling cup, which was then moved quickly over the entire turf surface in the pot. This watering procedure proved to be a considerably faster method than by using the spike setup.
4.3.1 Rain included in experiment
The waters used for the experimental growing of the turf samples in this thesis are often referred to as ‘treatments’, and these waters include several greywaters, Miracle- Gro® solution, and tap water. Refer to Chapter 3 (Section 3.5), or to Appendix C for a list describing the origins, compositions, and the identifying codes of the waters used on the turf or on the native flower specimens. Rain was part of the turf watering process because rain would generally not be excluded from domestic or community centre situations, where greywaters were used to grow turf. A rain gauge was used to determine whether there was sufficient rain to forego further watering with greywaters for a day or more. Quite often the appearance of water on the turf in the morning was sufficient to judge whether rain had fallen overnight, but the rain gauge often revealed that the total fall was 0.5 mm or less, which was insufficient (during the extended drought). See Appendix A for the measured monthly rainfall over the experimental area during the period 1/11/07 to 15/3/09, when seven months had from zero to 15 mm of rain. The total rainfall for 2008 over the experimental area was 346.2 mm, which was 62.2% of the Mean annual rainfall of 556.9 mm during the period 1971- 2000, as measured 8 km away at Melbourne Airport (Bureau of Meteorology 2015).
4.3.2 Watering quantity
The greywaters and water in control treatments were generally added as needed, often on a daily basis in hot weather. The standard watering volume of 300 ml was
approximately the same volume of water which would be deposited to each pot by a little less than 5 mm rainfall. The samples which were given Miracle-Gro® treatment had this applied at a minimum of 14 day intervals, which could be increased by a day or two if sufficient rain fell when Miracle-Gro® application was due. The procedure was to add 200 ml of the Miracle-Gro® solution, followed by 100 ml of tap water a few minutes later, with 300 ml of only tap water being added on watering days in between the 14 day intervals. It did not take long to realise that 5 mm of water added by rain and 5 mm coming from watering on a hot day, did not equate. Samples watered by rain tended to remain moist for longer periods because of factors such as air temperature and humidity, evaporation rate, and rate of addition of water. On a few very hot days the watering quantity, mainly for the Tall Fescue, was sometimes increased to 600 ml. This was done if it was noticed that some samples were showing
stress, or if watering would not be possible on the following hot day. The overall aim of watering was to keep the plants as free from water stress as possible. See Appendix B for the monthly volumes of greywaters applied per pot over the experimental period 9/11/07 to 15/3/09.
4.3.3 Watering treatments used on Spring and Summer planted turf
For an explanation of why some different treatments were applied to the Spring and Summer planted turf specimens refer to Section 4.2.5. The treatments that were applied to the turf specimens are indicated by the √ mark in Table 4.1.
Table 4.1 – Water treatments used on Spring and Summer planted turf Water Code Spring Summer Water Code Spring Summer
Water √ CPTW Shower √
CPTW √ √ M/Gro √ √
CPTWU √ CPDR √
ECTW √ ECDR √
Shower √ √ SHU √ √
SHU/5 √ CPTW SHU √
4.3.4 Reference fertiliser
Miracle-Gro® All Purpose Plant Food was selected as the reference fertiliser because:
1. It was considered to be easier to evenly apply a water soluble fertiliser to turf in a pot than to apply a solid fertiliser.
2. Suitability for its use on lawns and gardens was judged from listed details and instructions printed on an older packet of the fertiliser.
The newer packets bought for the project however did not have as specific application details and just stated “For All Flowers, Vegetables, Trees, Shrubs, Houseplants.”
The plant food had an NPK ratio of 15:13.1:12.4 and the major ingredients listed on the packets were:
1. Mono-Ammonium and Di-Ammonium Phosphates.
2. Urea.
3. Potassium Chloride.
The Miracle-Gro® All Purpose plant food was applied to the turf by first dissolving one level 15 ml scoop of the fertiliser in 4 litres of tap water, and then sprinkling 200 ml of this solution to each pot undergoing Miracle-Gro® treatment. The 200 ml of solution was added from a sprinkling cup while the cup was being moved around over the pot (Refer to Section 4.3 for details). After at least 30 minutes, 100 ml of tap water was added to each Miracle-Gro® pot to bring the added watering volume up to 300 ml. The standard watering volume in normal conditions was 300 ml, and so this procedure ensured that the total volume of water added to the Miracle-Gro® pots was the same as that added to the greywater pots.
The suggested interval for adding Miracle-Gro® is every 7 to 14 days however it was decided to be cautious, especially in hot weather, and to aim for a minimum of 14 days between treatments. Normal tap water was applied on all watering days in between Miracle-Gro® treatments. On a few occasions the addition of Miracle-Gro®
and the greywaters was also delayed by a few days because of rain.