Fertilizing the vegetable garden

Biology

It was hypothesized that a liquid fertilizer would make the Brassica rapa plant grow the tallest, the powder fertilizer would help create the second tallest plants, and the pellet fertilizer the shortest in all the experimental groups. This hypothesis is based on the different ways each type of fertilizer are applied and then absorbed by the plants and their soil. Liquid fertilizers were believed to be the most effective in causing rapid growth because "liquid fertilizers may also be applied to plant foliage where the nutrients are absorbed directly through the leaf surface. This foliar feeding provides nutrients to the plant very quickly," (Relf, McDaniel & Donohue, 2009).

To enhance the validity of the research, a control group of Brassica rapa receiving no fertilizer treatment was also included. It was hypothesized that the control group would be the shortest plants of all the groups because they did not receive any aid in the form of fertilizer. Fertilizers are made from various plant, animal, or mineral materials that are metabolized by the soil and plants and which promote growth ("Fertilizing Your Organic Garden," n.d.).

The hypothesis that the fertilizers would promote growth at all was proven false. In fact, the hypothesis that liquid fertilizer would promote the fastest growth, followed by powder and then pellet, was eliminated entirely. Of all the fertilizer conditions, the control group of plants demonstrated the most growth after the 64-hour time period. In fact, the control group plants grew about twice as much as the group receiving the pellet fertilizer or the powder fertilizer. Moreover, the plants receiving the liquid fertilizer exhibited zero growth: the only group to do so. This not only disproves the hypothesis, but completely reverses the expected results.

There are several possible reasons for the unexpected results. First, the fertilizers differed from each other not just in terms of their form as liquid, pellet, or powder. The fertilizers may also have had different chemical compositions, which would have a greater effect on the growth of the plant than what form that fertilizer took. Moreover, it was unknown which specific chemical fertilizers would be more conducive to plant growth in Brassica rapa in particular. Another possible reason for the unexpected results is differential application of the fertilizer. For this research, the same .07 grams of fertilizer was applied to each cell. Yet it is possible that some types of fertilizer, such as liquid fertilizer, require more or less than the .07 grams. Future research would take into account the different chemical compositions of fertilizers, making sure to control for those differences. Also, future research would take into account the fact that the same amount of liquid, pellet, or powder may not yield results. The commercial instructions for each of the fertilizers should be followed. Also, it would be helpful to monitor plant growth for more than 64 hours. Future research could also include plant varieties other than Brassica rapa in case this particular species exhibits unusual behavior when exposed to fertilizers.