The purpose of this experiment was to examine whether or not increasing the number of bean plants (Phaseolus vulgaris) would increase the stem height of a fixed number of corn (Zea mays) and if it would increase the above ground plant mass of the corn due to the beans’ nitrogen fixing abilities (Wagner 2012). Nitrogen is often the limiting nutrient for corn growth so our hypothesis was that increasing the number of bean plants would increase the growth of the corn (Osmond & Riha 1995).
One statistically significant difference was found in the comparison of above ground corn mass of Treatment 1 and Treatment 3 (Figure 2). Treatment 3 was shown to have a significantly larger above ground corn plant mass than Treatment 1 when subject to a two-value, single-tailed t-test (t4 = 2.456, 0.025 < p < 0.05).
This result suggests that increasing the number of bean plants from 1 to 3 had a benefit on above ground corn plant mass growth though no other significant differences were seen in the measurements. This result is likely due to the superior nitrogen competitive abilities of corn preventing legumes such as beans from taking up nitrogen (Chang & Shibles 1985). With a greater ability to take up nitrogen, the corn would be able to grow taller and grow more leaves, increasing the above ground plant mass (Chang & Shibles 1985). Other significant differences were not seen between the treatments which are likely due to the wide range of values collected for each treatment with an example being the Control standard deviation seen in Figure 2.
When comparing the corn stem heights, it was found that the control was significantly taller than Treatment 2 (t12 = 1.838, 0.025 < p < 0.05), and Treatment 4 (t14 = 3.751, 0.001 < p < 0.0025) on March 20, 2014 when subject to a two-value, single-tailed t-test. Treatment 2 was found to be significantly taller than Treatment...