Page 88 - rise 2017

Methodology
Composting procedure
Three ratios of tea waste and rice straw mixture were prepared. The ratio indicated the carbon to
nitrogen, C:N, ratio. The composts were prepared inside 10L barrel. The barrels were closed tightly to
prevent air to disrupt the composting at the early phase of degradation process.

Kjeldahl Method in Testing Nitrogen
Samples from each compost ratio were obtained and digested. The sample were later distilled and
titrated to determine the nitrogen content using the formula.

Spectrophotometer Method in Testing Phosphorus
5 ml of the sample was measured together with 5 ml distilled water were poured in a conical flask.
Next, 8.0 mL of combined reagent that was prepared previously was added into the conical flask
contain the sample mixture and were mix thoroughly. Then the sample was allowed at least 10
minutes (but not more than 30 minutes) for color development. Then, after 10 minutes the sample was
measured for absorbance at 880 nm using a reagent blank to zero the spectrophotometer.

Spectrophotometer Method in Testing Potassium
A potassium standard solution was prepared to cover the range 0 to 100 ppm potassium. Photometer
was set at 100 using the 100ppm potassium solution. Next, the 20, 40, 60 and 80 ppm potassium
standard solution was successively aspirated and a calibration graph was prepared. The potassium
content of the soil extract was determined by aspirating the solution, diluting as necessary in
ammonium acetate/acetic acid solution. The concentration was calculated by reference to the
calibration graph, taking into account any dilution.

Hydroponic Planting Procedure
Firstly, ¾ of containers such as polystyrene box or hydroponic sets was filled with tap water. Then,
the medium such as cotton, thread or sponge which has holes in the middle was immersed into the
water. Then 3 spinach seedlings were put into each holes of the medium. After 4-5 days, the seed
were germinated. A bin with lid was filled with 5 L of tap water and the organic liquid fertilizer was
added together with the fertilizer A and B with the ratio for 60: 40. The contents were mixed well.
The containers were covered with a lid. A cup of the mixed fertilizer solution (organic liquid fertilizer
+ tap water) was inserted into the container. The water in the container was added regularly. Other
than that, the fertilizer content was measured regularly by using EC meter. The steps above were also
repeated for chemical fertilizer. The growth of the plants was measured in 3 different parameters such
as the height of plants, the diameter of leaves produced, and the number of leaves produced.

Results and Discussion
Compost Maturity
Two parameters which are temperature and pH were measured weekly in order to observe the
maturity of the compost. The temperature of the compost are fluctuated which are not increase or
decrease linearly. The trend of the temperature indicate the respiration and degradation process occur
in the bins. If the temperature of compost increase, it means that the high respiration and degradation
process occurs on the compost. The pH of the composts was in a range of 7.00 to 9.00. The compost
matured when the temperature is in the range of 27.0 to 29.0 while the pH is in the range of 6.00 to
8.00. The compost degradation process has occurred for 11 weeks. This is because the environmental
factors and the size of the rice straw that has influenced the degradation process.

Nitrogen Content
The highest nitrogen content is in 70:30 ratios of rice straw and tea waste (6.75 g/L) while the lowest
is 30:70 ratios of rice straw and tea waste (3.24 g/L). However, 50:50 ratios of rice straw and tea
waste contain 3.73 g/L. Since the initial concentration of rice straw (4.27 g/L) is higher compared to
tea waste (2.17 g/L), meaning that the amount of rice straw may affect the concentration of nitrogen.
It shows the nitrogen content in rice straw affect the nitrogen concentration in fertilizer, the higher the
amount of rice straw used in fertilizer, the higher the nitrogen content.