THE EFFECT OF AVAILIBLE SOIL ON THE HEALTH AND PHYSIOLOGY OF THE SPINACIA OLERACEA PLANT (title should be THE EFFECT OF SOIL AVAILIBILTY ON THE HEALTH AND PHYSIOLGY OF THE SPINACIA OLERACEA PLANT – just a suggestion)
Abdul Aziz, Nash Robertson *Name should be put together with school information, no spaces*
Department of Biological Sciences, Saddleback College,
Mission Viejo, California CA 92692. (school address should not be italicized, look at correct formating)
Growing plants in a non-traditional setting has seen a rise in popularity. Due to lack of gardening space in urban settings, individuals are increasingly using techniques more akin to potting. With the hope of determining how an herb or vegetable, such as Spinacia olercea or the common spinach can be optimally grown in a potting environment with limited soil resources, the investigators will attempt to judge how the spinach plant will develop in pots, varying in sizes. (hypothesis clearly stated, but talk about growing plants to eat)Spinach seeds were purchased on 11 October 2011 from the Mission Viejo, California Home Depot. The 6-Gram Bloomsdale long standing spinach seeds are from the Martha Stewart Living Company; the seeds are USDA approved to be organic. The seeds were then taken to Saddleback College located in Mission Viejo, California. The greenhouse annex of the Math and Science building would be utilized as the site for planting and development. Observations were noted consistently on Monday, Wednesday, and Friday of each week, whilst on the 36th day after initial planting, the Spinacia oleracea were uprooted and health markers (Explain what health markers are) were measured. Final results and analysis indicate that there is no significant difference among the health markers of mass (p = 0.654), number of leaves (p = 0.663), (and) root depth (p = 0.819). However, the findings suggest a significant difference in diameter of the Spinacia oleracea stalk (p = 0.021) (talk about what statistical analysis you did to get these numbers, did you use anova with Bonferoni correction, two tailed t-test, etc). Appropriated soil volumes appear to neither hinder nor benefit plant health.
Introduction
Harvesting fruits and vegetables in non-traditional urban settings has become commonplace, due in part to green initiatives as well as economic benefits, which befall it. Lack of gardening space in urban settings has compelled individuals to increasingly use techniques, which are more akin to potting. It is estimated that urban dwellers may spend anywhere between 40%-60% of their income on groceries and other various foodstuffs (Wakefield, 2007). Especially in turbulent economic times there is no surprise many communities have seen an exponential rise in urban-gardening. Cities such as Detroit, Chicago, Toronto, and Los Angeles to name a few have incorporated community gardens within residential areas in order to expedite this growing trend. Urban-gardening can be observed and discussed through various methods, as a socio-cultural event and implication on community, but also through a biological and botanical lens. Gardening for ones own consumption promotes individuals to cultivate the healthiest produce. Through this reasoning lies the pursuit of attempting to create optimum circumstances for plant health and physiology. Dr. Coley discusses the significance of resource and soil availability in regards to plant growth ascertaining that when resource(resources) are limited, plants’ leaf lifetime, is affected (1985).
Spinacia oleracea or the common spinach plant is a familiar staple in the inventory of urban-gardens; and as the plant is consumed, its benefits begin to take hold. Spinacia oleracea has been found to be nutrient rich, containing essential vitamins including K, A, C, and E, while also proving rich in anti-oxidants. Whereas the nutritional contributions of the plant sway the urban-gardener in the plants favor, reasons for planting spinach does not stop here. On account of the Spinacia plants’ accessibility in regards to temperature range, which is from 5-20 degrees Celsius, it allows spinach to have a diverse temporal schedule for planting and growth (Boese, 1990). The researchers have decided to observe the implication of various soil amounts within pots of Spinacia oleracea. Four health markers (what are health markers? What did the researchers decide what to use as health markers?) have been chosen to help to ascertain the wellness of the plant. The researchers hypothesize that the markers of physiological health will be significant amongst the Spinacia oleracea having plentiful soil. (hypothesis stated)
· Hypothesis stated
· Spinach background described
· Reason to do research stated
Materials and Methods
Spinacia oleracea seeds were purchased from Home Depot in Mission Viejo, California on 11 October 2011. The ‘Bloomsdale’ long standing spinach seeds were collected and packaged by the Martha Stewart Living Company; the seeds are USDA approved to be organic. The study was performed at the greenhouse annex of the Math and Science building located at Saddleback College in Mission Viejo, California. The greenhouse setting provided minimal changes in temperature (25° - 35°C) while protecting the plants from potentially lethal pests. Saddleback College donated “Pro-mix BX with Mycorise” potting soil manufactured by Premier Horticulture inc. and 30 pots, (semi colon) ten pots of three different sizes, (take out comma)to the researchers for growing and housing the Spinacia. All measurements of mass were calculated by a top loading balance provided by the Saddleback College Biology department.
Research started on 11 October 2011 by filling the different pots with a measured mass of soil. The ten small pots contained a volume of approximately 175 cm3 and were filled with 85 g of soil. The ten medium pots contained a volume of approximately 300 cm3 and were filled with 175 g of soil. The ten largest pots contained a volume of approximately 550 cm3 and were filled with 360 g of soil. All 30 pots were positioned on a table adjacent to the greenhouse window, to maximize sunlight exposure, and remained stationary for the duration of the research. One seed was allocated to each container and planted at a soil depth of 3 cm. Once the sowing was complete, the researchers observed the volume of water needed in order to saturate the soil in each of the pot sizes. The smallest pots received 25 mL of water, the middle pots received 50 mL of water, and the large pots received 75 mL of water. Subsequent watering of the Spinacia utilized the calculated water volume and took place at a consistent time every Monday, Wednesday, and Friday. As the plants matured and sprouted leaves the researchers added a “misting” of the spinach leaves with water filled spray bottle to the maintenance routine.
The Spinacia was allowed to grow for five weeks before the plants were “uprooted” to determine the physiologic health of each individual plant. Uprooting the plants consisted of emptying all (of) the soil from the pot and running the spinach under light water to wash the soil away from the root structures. After the washing, all the plants were air dried for 30 minutes before quantitative measurements were processed. The major factors considered for the physiological health of the Spinacia were the mass, the number of leaves, size of edible leaves, and root diameter. All the data was entered into Microsoft Excel and a statistical analysis was performed on each of the aforementioned metrics to determine if there was a statistical difference between soil volumes.
Results
The mean mass of spinach plants in the 175 cm3 pot was 0.192 g ± 0.071, the mean mass of spinach plants in the 300 cm3 was 0.144 g ± 0.041, (and) the mean mass of spinach plants in the 550 cm3 was 0.296 g ± 0.186. The statistical analysis on the average mass of the spinach plants indicated that soil volume had no significant difference according to results of an ANOVA (p > 0.05) and a Bonferroni correction (p > 0.05).
Figure 1. The mean masses of the spinach plants indicated no significant difference (p = 0.654, ANOVA, n = 10) dependent on three variant soil volumes. The statistical insignificance in the difference of the three average masses was confirmed by a Post Hoc Bonferroni correction. Error bars are mean ± SEM.
The mean number of leaves on each of spinach plants in the 175 cm3 pot was 5.0 ± 1.2, the mean number of leaves on each of spinach plants in the 300 cm3 was 5.4 ± 0.76, (and) the mean number of leaves on each of spinach plants in the 550 cm3 was 6.2 ± 0.76. The statistical analysis on the average number of leaves on each of the spinach plants indicated that soil volume had no significant difference according to results of an ANOVA (p > 0.05) and a Bonferroni correction (p > 0.05).
Figure 2. The mean number of leaves on the spinach plants indicated no significant difference (p = 0.663, ANOVA, n = 10) dependent on three variant soil volumes. The statistical insignificance in the difference of the three average masses was confirmed by a Post Hoc Bonferroni correction. Error bars are mean ± SEM.
The mean root depth of spinach plants in the 175 cm3 pot was 4.0 cm ± 1.0, the mean root depth of spinach plants in the 300 cm3 was 4.4 cm ± 0.9, (and) the mean root depth of spinach plants in the 550 cm3 was 4.8 ± 0.46. The statistical analysis on the average root depth of the spinach plants indicated that soil volume had no significant difference according to results of an ANOVA (p > 0.05) and a Bonferroni correction (p > 0.05).
Figure 3. The mean root depths of the spinach plants indicated no significant difference (p = 0.819, ANOVA, n = 10) dependent on three variant soil volumes. The statistical insignificance in the difference of the three average masses was confirmed by a Post Hoc Bonferroni correction. Error bars are mean ± SEM.
The mean stalk diameter of spinach plants in the 175 cm3 pot was 0.6 mm ± 0.16, the mean stalk diameter of spinach plants in the 300 cm3 was 0.9 mm ± 0.20, (and) the mean stalk diameter of spinach plants in the 550 cm3 was 1.2 ± 0.11. The statistical analysis on the average stalk diameter of the spinach plants indicated that soil volume provided a significant difference (p = 0.021) according to results of an ANOVA. Furthermore, a Post Hoc Bonferroni correction supported the significant indication, specifically illustrating the variance between the smallest 175 cm3 pot and the largest 550 cm3 pot.
Figure 4. The mean stalk diameter of the spinach plants indicated a significant difference (p = 0.021, ANOVA, n = 10) dependent on three variant soil volumes. A Post Hoc Bonferroni correction confirmed the statistical significance between the smallest and largest soil volumes. Error bars are mean ± SEM.
The only statistically significant result from this trial was observed in the comparison of the average diameter of spinach plant stalk between the containers with the smallest and largest soil volumes.
Discussion
The first indicator of plant health chosen for this experiment was mass of dried plant. On a previous study of growth kinetics on spinach plants it has been observed that dried plant mass was an indicator of overall health (Boese, 1990). The results of this trial indicate no significance between pot sizes and dried (plant) mass, as can be seen in figure 1. Contrary to researcher expectations the smallest volume plants outweighed the plants with the 300 cm3 of soil. Although the plants in the mediums sized pots were the smallest by mass, the plants provided the researchers interesting data. The medium sized potted plants began to flower, and while plants in the other varied sizes also flowered, the 300 cm3-potted plants were the most numerous flowerers. This may be a result of the greenhouse ambient temperature averaging 28 degrees Celsius over the duration of the experiment. The preferred temperatures for optimal spinach growth as noted by Dr. Boese, is in fact between 5, and 16 degrees Celsius (1990).
The second health marker studied by the researchers focused on the quantity of leaves sprouted per individual plant. Analysis of leaf quantity has been used previously as a nondestructive way in which to measure plant health (Wood, 2000). The researchers noticed a trend regarding greater soil content resulting in more leaves as seen in figure 2. However the ANOVA showed not(no) statistical difference in leaf number.
Root depth was the third health marker observed by the researchers, measuring the length of the longest root. The decision to include this factor as a health marker was influenced by previous studies, correlating root restriction to plant health. One such study found that root restriction resulted in depressing production in both root and shoot for cucumber plants (Kharkina, 1999). The researchers found that this metric(that the length) had the least variance among the differing soil volumes, as indicated in figure 3.
Stalk diameter was the last health marker chosen by the researchers, who were able to locate numerous studies regarding stalk diameter. Wider stalks can support taller and weightier plants, indicating superior health. One such study found a relation between stalk diameter and height of maize (Earley, et al, 1965). As can be noted in figure 4 stalk diameter measurements showed a significant difference between the three potted sizes, in which the largest potted plants provided the widest diameter stalks. (explain why there might be a difference in root diameter between the three pot sizes, and add some literature explaining this)
While statistical analysis does not show any significant difference, the researchers have observed the viability of spinach plants grown in smaller volume pots. These observations contradict what has been previously stated in articles regarding proper soil volumes for spinach. The implications for viable produce grown with less soil are immense, especially in urban-gardening communities, for which space is limited and must be used sparingly.
Given the opportunity, the researchers would pursue the study of soil amounts and plant health by continuing to push the boundaries of soil necessity, attempting to observe how little soil volume can be implemented until a significant difference is ascertained. The researchers would eventually attempt to calculate and analyze the nutrient content between the spinach plants grown in various soil amounts, again hoping to achieve an optimally healthy spinach plant using the least amount of soil volume.