Andrew Pham Duckweed FD

7/31/2019 Andrew Pham Duckweed FD

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Andrew Pham

Chenchen Shen

BI213-072

3/1/12

The Effect of Fertilizers on Duckweed

Duckweed also known asLemnoideae, they are tiny water plants that grow in

mainly pond water. They are high protein plant that grows very rapidly and is used in

many types of research. My group is interested in what are the effects of All-Purpose

Fertilizer and Complete Organic Fertilizer on duckweed. From research, I found out that

increasing levels of N fertilizer in the pond increased biomass yield and crude protein

content of the duckweed. (Lampheuy, Preston, Thy 2004) With this resource, I can

hypothesize that with the help of fertilizers, duckweed will be able to flourish. With that,

knowing only so little about duckweed and its potential, will duckweed actually take

advantage of the fertilizer in our experiment?

Our method was to obtain an organic fertilizer, and all-purpose fertilizers. With it

we diluted 5ml of each fertilizer into 200ml of DI water. We obtained 180 pieces of

duckweed and placed 20 into 9 petri dishes. 3 was labeled control and 40 ml of water

was placed in. 3 more petri dished was labeled organic fertilizers and placed 40ml of the

diluted solution into the dish. The last 3 was done accordingly so. We have a trial of 3

weeks and the results were recorded each week by counting the duckweed each week.


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Based on the data we

recorded, we had some

interesting results. The best

treatment on our experiments

was the control group. Based on

Figure 1 the population of the

control group flourished over

time. The worst treatment was

the complete organic because

due to the increase of pH its

population was decreased to

zero. Figure 2 shows the standard deviations for all the treatment and how the numbers

were distributed. The significance of the results is that the duckweed was able to grow

without the presence of fertilizers, and therefore my hypothesis was incorrect because in

this case the duckweed did not benefit from the fertilizers.

My results did not support my hypothesis. I believe the reason why our duckweed

in the organic fertilizer died is because the concentration in the petri dish is high and that

we over fertilized our duckweed. Our organic fertilizer had a 6-7-7 ratio of nitrogen-

phosphorous-potassium. Due to the fact that its being over fertilize of phosphorous, more

phosphorous increase pH levels in the soil and could kill plants (Mitchell and Adams

2000). Plants wants to be around the 6-7 pH and so conclude that the fertilizers increased

the pH level in the water, which resulted in reductions of duckweed. These result are

important because it could help future consumers who would used fertilizers could use

Figure 1. This chart shows the relationship between the populations

of the Lemnoideae,duckweed of all three experiments (control,

complete organic and all purpose fertilizers). The control group

flourishes where as the complete organic fertilizers killed theduckweed after the first week. As for the all purpose fertilizers, it

grew after the first week but then died.


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my results and not make the same mistake when they are using fertilizer and not over

fertilizing their plants.

In conclusion, this experiment would have worked if we didnt have to work with

such small petri dishes therefore my hypothesis was not supported. The presence of

fertilizers inhibits growth of duckweed based on my experiment. In future experiments, I

would have used a larger container and used fewer fertilizers to prevent the pH level from

increasing and killing the duckweed.


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Figure 2. This graph shows the standard deviation of all the treatments and how the numbers were distributed.


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Works Citation

Lampheuy Kaensombath, Thy San and Preston T R 2004: Manure or biodigester

effluent as fertilizer for duckweed.Livestock Research for Rural Development, Vol. 16,

Art. #17. Retrieved February 8, 112, from http://www.lrrd.org/lrrd16/3/lam16017.htm

Mitchell, Charles, and James Adams. "Lowering Soil PH." Clemson University,

17 Jan. 2000. Web. 27 Feb. 2012. .

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Andrew Pham Duckweed FD