Eric,+Alex,+Brian+R.

HEY GUYS, SORRY IT TOOK ME SO LONG TO GET TO READING AND COMMENTING ON YOUR RESULTS AND DISCUSSION. I REALIZE YOUR PAPER IS DUE TODAY, IF YOU WANT TO MAKE CHANGES BASED ON MY COMMENTS AND PASS IN THE PAPER ON TUESDAY WITH YOUR POSTER YOU MAY WITH NO GRADE PENALTY. The Effect of Earth Worm Population on Compost Decay Rate
 * Names of group members: Eric Pinsker-Smith, Brain Rolincik, Alex Schecter.**
 * Title **


 * Introduction **

Compost is a partially decomposed organic material that can be used as fertilizer[4]. In order to make compost, one must have microorganisms to chemically break down material, and macro organisms, larger organisms such as worms, for physical decomposition. This physical decomposition includes the grinding, biting, and tearing of the material into smaller pieces, to put it into a form more easily digestible for microorganisms[5]. In turn, microorganisms take nutrients from the soil in the form of carbon and nitrogen[5]. If there is a larger amount of microorganisms in a compost pile, they will use up more of the nitrogen and carbon in the materials and break them down faster[5]. Although different organic materials have different carbon to nitrogen ratios, a ratio between 25:1 and 30:1 is optimum for fast decay[5]. For example, fruit waste has a ratio of 35:1, grass clippings have a ratio of 12-25:1, pine leaves have a 60-100:1 ratio,and wood chips have a 500-700:1 ratio[5]. Therefore, the different materials that go into the compost will affect its decay rate. In addition, the movement of air through compost, water present in compost, and temperature affect compost decay rates[5]. Microbial activity occurs most rapidly in thin water films on the surface of organic material. Occasional precipitation and adding constant water amounts daily should provide this optimal water amount. The microorganisms are the most important decomposers, using the nitrogen and carbon, while the macro-organisms physically break down compost through eating microorganisms and organic material, digesting and depositing[5].The main difference between compost and the soil is that soil is made from the compost material. Other differences are the the composition and the competence[1]. Competence is the amount of water that the soil can hold[4]. The soil has small "granules" that make it up, while the original compost material does not have this composition. Therefore, the soil can be separated from the raw compost material by using a grate that only allows the soil to fall through it, and therefore weighing it separately will show the amount of decay that the compost material is undergoing[6]. While microorganisms do the important chemical decomposition, if there is a larger amount of macro-organisms, namely worms, in a compost pile, they will promote the microorganisms to use up more of the nitrogen and carbon in the materials and break them down faster. This investigation is meant to prove this relationship between macro-organisms and compost decay rate, by quantifying the benefit that the physical decomposition by the macro-organisms have on the breakdown of the material. **Therefore, it is hypothesized that with a constant amount of microorganisms, a larger population of earthworms will increase the rate of compost decay.**


 * Materials and Methods **

1) Fill up three 18 gallon bins with 10lbs of rough soil (soil with minor obscurities in it), 1 ounce of grass clippings, 2 ounces of leaves, 1 apple, 1 banana, and 2 pieces of paper, one cup of water and a packet of microorganisms 2) In one bin don't add any worms, one of the bins add 4 worms, and in another add 8 worms. 3) Leave bins next to each other in Eric's yard. 4) Every 3 days add, another cup of water to each bin. 5) Every 3 days, use a "metal-mesh" or metal hardwire with half-inch openings to separate the compost (the unbroken down materials listed in step one) from soil. 6) Once the soil is separated from raw compost material, weigh it using eric's bathroom scale (measures in pounds) 7) Calculate how much compost has turned into soil by adding the amount of soil produced to the previous total amount.


 * Results **

Data Table 1: Total Soil Production (in lbs)
 * DATE || BIN A (8 worms) || BIN B (3 worms) || BIN C (0 worms) || Other observations ||
 * Start (5/1) || 0 || 0 || 0 ||  ||
 * 5/3 || .5 || 0 || 0 ||  ||
 * 5/6 || .5 || .5 || .5 ||  ||
 * 5/9 || 1 || .5 || 1 ||  ||
 * 5/12 || 1.5 || 1 || 1 || Bin A steaming dramatically ||
 * 5/15 || 3 || 1.5 || 1 || Bin B is beginning to steam ||
 * 5/18 || 3.5 || 2 || 1 || Bin B steaming more ||
 * 5/21 || 4 || 3 || 1 || All bins no longer steaming ||
 * 5/24 || 4.5 || 4 || 1 ||  ||

Bin A had a total of 4.5 lbs of soil produced from compost decay, this was the most of the three bins. Bin B had 4 lbs total of soil production, and Bin C had 1 lb total of soil production. The average decay rate for the Bin A was .188 lbs/day (4.5 lbs/24 days), for Bin B it was .167 lbs/day (4 lbs/24 days), and for Bin C it was .042 lbs/day (1 lb/24 days). There are many patterns in the relationship between earth worm presence and compost decays rate which can be seen in the graph. The first thing that may be noticed about the data is the separation of the data sets on the last day of soil measurement. The final day is the culmination of all of the compost decay, and it shows that Bin A, holding 8 worms, has the highest total soil production of 4.5 pounds. Bin B, holding 3 worms, had the second largest soil production of 4 pounds, while Bin C, holding 0 worms, had only 1 pound of compost decay. Looking more specifically to the data trends, there is a noticeable difference between the compost decay rates of Bin A and Bin B and Bin C. In between the first 3 days of the compost breakdown process, Bin A had already produced .5 lbs of soil while the other two bins, still had 0 lbs produced. On day 6 the soil production totals were equal, but interestingly, Bin A and Bin C had gained .5 lbs of soil from day 6 to 9, while Bin B stayed at a total of .5 lbs. If this interval of time was isolated and looked at by itself it would appear that the worm population doesn't effect the compost decay rate; the bin with 0 worms decayed at the same rate as the bin with 8 worms, which was faster than the decay in the bin with 3 worms. Despite those counterintuitive results, the overall data trend starts showing between days 9 and 18. Between these 9 days, Bin C has no decay, while Bin B has a rate of about .167 lbs per day (1.5 lb/9 days), while Bin A has the highest decay rate of about .278 lbs per day (2.5 lbs/9 days).


 * Discussion **

The hypothesis was that a larger amount of earthworms in a compost pile will increase the rate of compost decay. The overall average decay rate, from day 0 through 24, for Bin A was .188 lbs per day (4.5 lbs/ 24 days), for Bin B was .167 lbs per day (4 lbs/24 days), and for Bin C was .042 lbs per day (1 lb/24 days). The data strongly supports the hypothesis; the bin with the most worms had the highest average decay, the bin with the second largest amount of worms had the second highest decay rate, and then the bin with no worms had a drastically lower decay rate. The reason why the hypothesis is not completely proven is due to the total amounts of compost produced by the end of the experiment. While Bin A had 4.5 lbs of soil production, Bin B had 4 lbs of soil production. Based on Bin A's decay rate of .167 lbs/day from day 18 to 24 (1 lb/6 days), and Bin B's decay rate of .334 lbs/day from day 18 to 24 (2 lbs/6 days), it is difficult to predict whether or not the soil production of Bin B would surpass that of Bin A if more measurements had been taken.

The overall trend of soil production was caused by the earthworms' influence on the decomposition of the compost material. As was shown by the data, the microorganisms can work to break down the compost a little bit even without any help from large physical decomposer's (macro-organisms), like earthworms; This is shown through Bin C having a total of 1 lb of soil produced with 0 worms in it. At the same time, the presence of the earthworms in addition to the microorganisms in the other bins drastically increased the speed of decay. This supports the fact that microorganisms must work together with macro-organisms to decay compost material and produce soil (5). Also, it suggests that the physical decomposition from macro-organisms is just as important as the chemical breakdown from the microorganisms, if not more important, because 3 worms led to quadruple the final soil production of 0 worms, and 8 worms led to more than that. Furthermore, the microorganisms can't decay as much material without macro-organisms to help them. In addition, the relationship between the amount of earthworms and compost decay is useful for ensuring the fastest compost decay possible for large composting sites such as the Wellesley Town Dump (6).

As is the case with most experiments, this experiment was not perfect. One limitation of this particular study of the effect of earthworm population on compost decay rate was the limited amount of time that was able to be devoted to the experimentation. This limitation of time contributed to why the results only strongly supported the hypothesis. If there had been more time to gather data then the results would likely have shown whether or not the decay of Bin B would match or surpass that of Bin A. In addition to this, something that might lead to more concrete and conclusive results would be to have several bins with several different amounts of worms in them instead of simply having three different amounts in three bins. With this change, it would most likely give more complex results, perhaps hinting at an ideal ratio of microorganisms to earthworms for maximum decay. It might suggest that there is a certain amount of earthworms above which the decay rate may stay the same or maybe drop. Therefor, having several bins with several amounts of earthworms could drastically alter the validity of this experiment's hypothesis. One other concern regarding the data collection was the accuracy of the bathroom scale. In this experiment an analog bathroom scale was used so measurements may have been slightly inaccurate. In order to get rid of this possibility for error, a digital scale would have been used. A digital scale would cause measurements to be solely based off of the accuracy of the scale, and they would not be altered by inaccurate reading of a the needle on the scale.

1) Composting." // Earth911 //. Earth 911, 2007. Web. 27 Apr. 2011. 
 * Sources **

2) "Composting With Worms - Earth911.com." // Earth911.com - Find Recycling Centers and Learn How To Recycle //. Earth911, 2 Apr. 2007. Web. 27 Apr. 2011. .

3) Micdowel, Sonji. "Links & Resources." // Home Composting Made Easy //. Web. 27 Apr. 2011. .

4) Tarbuck, Edward J., and Frederick K. Lutgens. // Earth Science //. Upper Saddle River, NJ: Pearson Prentice Hall, 2009. Print.5)"The Science of Composting - Composting for the Homeowner - University of Illinois Extension."// Untitled Document //. University of Illinois, 2008. Web. 27 Apr. 2011. .

<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">6) Wellesley department of Public Works --> Wellesley Town Dump.oo