Due to unforeseen circumstances, the location of my study had to be changed; fortunately, I was able to put together a small semi-manipulative experiment in my own backyard. There are 3 planter boxes located almost side-by-side in the middle of the yard, all had aged dirt and detritus from the last time someone had grown plants, my best guess would be the prior summer given the appearance when I moved in this summer. For this experiment, I have set the planters up as my three different gradients by leaving one untouched, one had various rocks added on top of the dirt and detritus, and the last had two bags of fresh soil spread on top. I then added some wildflower seeds to all three of the planters, I distributed the seeds based on weight (splitting the packet into thirds) and spread as evenly across the planters as possible.
After a week, I began to observe the first of the seeds sprouting in the planter box with fresh soil added, due to the lack of rain we have experienced this season so far, I believe the other two planters have lacked the moisture necessary for the seeds to sprout.
- Based on my observations so far, I am going to try to observe the species richness and diversity that can be found in these three environmental gradients.
- I have recorded the temperature/weather everyday in order to track how the organisms present in each planter respond to the changing weather. As noted before, the planter with the added soil seems to present the most green plant matter, mostly small sprouting seeds, which is again most likely due to the moisture present within the fresh soil which the older dirt does not contain given the warm, dry season that’s been experienced and the older dirt is compacted down, making it harder for the seeds to penetrate and access any nutrients or water that may be present. As we approach the rainier season, I will be able to observe how the plant matter will potentially grow over time. All three planters have evidence of spider activity (webs) leading me to believe there will be insect and other bug activity present in the planters.
- I hypothesize that the moisture and nutrients more readily available in fresh soil provides more optimal environment for plant and insect organisms, therefore I predict that the plant growth will continue to outperform the planters without added soil and the overall productivity will be increased in the planter with fresh soil.
- A potential response variable will be the number and size of plants growing in each planter. A potential explanatory variable would be the nutrient and moisture levels present in each planter.
This should be an interesting experiment!
You mentioned that you hypothesize that the nutrients and moisture in fresh soil will lead to a more optimal growing environment for plants and insects. You also mentioned that the old planters have quite hard packed soil. Have you considered aerating them to be loose like the new top soil is? I think the hard soil could be a confounding variable that would make it harder to draw a conclusion about nutrient and moisture levels contribution to plant environment.
You also mention that your response variable will be the size and number of plants. Have you decided how to weigh these two variables? For example, in one pot you have a single large plant growing and in the other you have a dense carpet of tiny plants. How do you decide which pot is showing more growth? I’m sure in real life it won’t be that cut and dry, but it might be worth thinking about for when you need to interpret your data.
I hope these ideas are somewhat helpful. Overall I think your hypothesis is clearly defined and so are the parameters of your experiment. Best of luck with the data collection and I hope your paper goes well! 🙂
Response as Part 2 of Blog Post 5:
As someone who also had to switch their observation area due to unforeseen circumstances, I admire your ingenuity! My first thought, a your post was from two weeks ago, is curiosity of how our recent rainstorm after the drought affected your planters! You may have to plan for potential future abnormal weather. I also wonder how planting wildflowers outside the growing season will impact your research. Reading through your post, some other variables I encourage you to think about is: potential differences in light from the canopy cover, potential weed growth, and if you’ll replace the top soil or remove fallen leaves in your two experimental planters. Your initial hypothesis seems good for this point. I like how it is flexible, but also specific enough to build from.
Response as Part of Blog Post 5:
What an interesting project! I think you are on your way for have a well-developed idea. One thing you might consider adding into your paper is the concept of resilience. If there is growth within the pots without fresh soil, would you be able to comment on the resilience threshold of the particular system? Additionally, because you state you do not know what was in the pots previously, I believe there would be a chance that your treatment didn’t start off the same from the beginning which could impact your results in the long run. I’m looking forward to reading more about your project!