Padi Huma Taragang (Week 4)

For the final week of this mini project, we decided to revert the watering amount to 500 ml with the same watering frequency. Below is the result for the fourth week. 

Soil Sample	Number of Seeds Sowed	Germination Rate (%)				Mortality Rate (%)
		W1	W2	W3	W4	W1	W2	W3	W4
A (sandy loam)	50	53	82	82	82	0	0	0	0
B (silt loam)	70	60	84	88	88	0	0	0	0
C (sand)	50	80	90	90	90	0	0	0	0
D (clay loam)	70	57	70	70	70	0	0	8.2	22.9
E (loam)	50	62	92	93	93	0	0	0	0

The data above also showed that Plot C has the highest germination rate on the first week. This is very likely influenced by the type of soil Pot C has, which is sand. Sand is known to be composed of very large and coarse particles which results in good aeration and porosity. Thus, this enables the seeds to sprout efficiently because the roots are able to penetrate freely and deeply into the soil making the root growth not limited. Pot E which has loam soil shows the second highest of germination rate on the first week. Loam is made up of medium-size soil particles and it is also a type of soil which has the best porosity and decent aeration.

On the contrary, Pot D showed the lowest germination rate on the first week. This may be because the type of soil in Pot D is clay loam which meant the soil is dominant in clay. Clay-ey soils tend to stick together, especially when wet. Also, Clay loam has very fine particles that are heavy result in poor porosity and poor aeration. In short, the roots in Pot D have very limited growth and cannot penetrate in to soil easily, as well as lacking in oxygen.

Plants data at about 2 weeks old:

Soil Sample	Average Length (cm)			Fresh Weight (g)	Dried Weight (cm)
	Whole	Shoot part	Root Part
A (sandy loam)	40.83	32.97	7.86	2.60	0.69
B (silt loam)	37.08	31.07	6.01	2.12	0.49
C (sand)	23.87	18.52	5.35	1.45	0.33
D (clay loam)	23.90	19.43	4.47	1.37	0.36
E (loam)	35.84	28.48	7.36	2.55	0.62

Plants data at about 4 weeks old:

Soil Sample	Average Length (cm)			Fresh Weight (g)	Dried Weight (cm)
	Whole	Shoot part	Root Part
A (sandy loam)	41.62	36.65	4.97	3.68	1.67
B (silt loam)	37.15	32.04	5.11	3.60	1.55
C (sand)	24.07	19.15	4.92	1.87	0.76
D (clay loam)	30.80	27.38	3.42	2.40	0.61
E (loam)	38.30	33.95	4.35	3.50	1.49

Figure 1: Average height of plants and their growth rate

From the data above, plants in Pot B have the highest growth week, while the lowest is plants growing in Pot D. There are several environmental factors that affect plants growth rate. The most important ones are temperature, moisture supply, soil aeration and structure, biotic factors, supply of mineral nutrients, absence of growth – limiting substances, as well as radiant energy. Each factor is correlated to each other, and can be a limiting factor. 

Temperature is the measure of heat intensity either on the plant’s surroundings or in the soil. It can directly affect absorption of water and nutrients. Nitrifying bacteria are inhibited by low temperature which could decrease soil pH during hot weather due to activities of microorganisms.Also, plant growth is restricted by low and high levels of soil moisture. However, it can be regulated by improving drainage and irrigation. Like temperature, good moisture content in soil improves nutrient uptake by plants. Radiant energy is the quality, intensity, and duration of light exposure to the light or sunlight.

On the other hand, Compact soils of high bulk density and poor structure are aerated poorly. Pore space is occupied by air and water so the amount of air and water are inversely proportional to the amount of oxygen in the soil. On well drained soils, oxygen content is not likely to be limiting to plant growth. Biotic factors include diseases, the influence of root knot nematodes, presence and growth of weeds which would compete for moisture, nutrients and light. Supply of mineral nutrients include the availability of macronutrients and micronutrients in the soil for plants to use. Those elements that are needed for higher plants to complete all life functions, and that the deficiency can be corrected only by the application of the specific element causing the deficiency.

Comparison of plants progress from Week 1 to Week 4:

Pictures are arranged according to week.
Top Left to Right - Week 1, Week 2
Bottom Left to Right - Week 3, week 4

Notes: the decrease of seedlings number in the pictures is because we dug 20 plants from each soil - 10 for 2-week-old, and another 10 for 4-week-old.

Pot A

Pot B

Pot C

Pot D

Pot E

Deficiency Symptoms

There were several deficiency symptoms observed in Pot C and Pot D.

Pot C 

- leaves discolouration (turning pale green, almost light yellow)

- this type of deficiency is caused by shortage of sulphur supply.

- shortage of sulphur supply is rare, but are possible to occur when the pH is too high, or excessive amount of calcium in the soil.

- in this case, excessive amount of calcium in soil may be the cause. this is because based on the heavy metal analysis, soil sample C has the highest level of calcium in parts per million. 

- from the macronutrient analysis, soil sample in Pot C possesses the lowest amount of sulphur. 

Pot D

- growth is slow

- browning of leaves tips and margins.

- yellowing and browning of leaves are uniform, spreads from the tip.

- this type of deficiency is diagnosed as nitrogen deficiency.

- based on the macronutrient analysis, soil sample D has medium amount of nitrogen.

- also, soil sample in Pot D has the lowest pH which is 4.76. this could affect nutrient availability since most nutrients are taken up efficiently by the plants within the pH range of 5.5 - 8.5.

HEAVY METAL ANALYSIS

Table 1: ICP-MS result for soil sample A

Table 2: ICP-MS result for soil sample B

 Table 3: ICP-MS result for soil sample C

Sample ID	Element	Mean/Average(ppm)		Sample ID	Element	Mean/Average(ppm)
C1	Pb	0.004		C2	Pb	0.003
C1	As	0.025		C2	As	-0.006
C1	Cd	-0.001		C2	Cd	-0.001
C1	Ni	0.011		C2	Ni	0.002
C1	Cu	-0.052		C2	Cu	-0.040
C1	Mn	0.530		C2	Mn	0.285
C1	Fe	20.454		C2	Fe	9.018
C1	Zn	0.274		C2	Zn	0.078
C1	Mg	48.189		C2	Mg	26.561
C1	Ca	Saturated		C2	Ca	1320.218
Sample ID	Element	Mean/Average(ppm)
C3	Pb	0.011
C3	As	0.000
C3	Cd	-0.001
C3	Ni	-0.002
C3	Cu	-0.026
C3	Mn	0.145
C3	Fe	4.674
C3	Zn	0.054
C3	Mg	13.103
C3	Ca	730.298

  Table 4: ICP-MS result for soil sample D

Sample ID	Element	Mean/Average(ppm)		Sample ID	Element	Mean/Average(ppm)
D1	Pb	0.202		D2	Pb	0.169
D1	As	0.013		D2	As	0.014
D1	Cd	-0.002		D2	Cd	-0.002
D1	Ni	0.123		D2	Ni	0.106
D1	Cu	0.121		D2	Cu	0.101
D1	Mn	1.314		D2	Mn	1.135
D1	Fe	228.080		D2	Fe	208.107
D1	Zn	0.533		D2	Zn	0.432
D1	Mg	14.217		D2	Mg	11.331
D1	Ca	78.058		D2	Ca	9.081
Sample ID	Element	Mean/Average(ppm)
D3	Pb	0.073
D3	As	-0.010
D3	Cd	-0.001
D3	Ni	0.044
D3	Cu	0.038
D3	Mn	0.522
D3	Fe	100.045
D3	Zn	0.193
D3	Mg	4.534
D3	Ca	3.534

  Table 5: ICP-MS result for soil sample E

Sample ID	Element	Mean/Average(ppm)		Sample ID	Element	Mean/Average(ppm)
E1	Pb	0.291		E2	Pb	0.105
E1	As	0.019		E2	As	-0.001
E1	Cd	-0.001		E2	Cd	-0.001
E1	Ni	0.247		E2	Ni	0.098
E1	Cu	0.268		E2	Cu	0.098
E1	Mn	2.881		E2	Mn	1.192
E1	Fe	232.080		E2	Fe	83.698
E1	Zn	1.307		E2	Zn	0.577
E1	Mg	20.604		E2	Mg	7.948
E1	Ca	74.639		E2	Ca	36.578
Sample ID	Element	Mean/Average(ppm)
E3	Pb	0.095
E3	As	-0.005
E3	Cd	-0.001
E3	Ni	0.085
E3	Cu	0.084
E3	Mn	1.074
E3	Fe	73.634
E3	Zn	0.504
E3	Mg	7.082
E3	Ca	34.846

*Sample ID with 1 - diluted to 25 ml

*Sample ID with 2 - diluted to 50 ml

*Sample ID with 3 - diluted to 100 ml

Further discussion will be made in the full report.