Weed And Soil Assessment For The Parking Lot “Islands” At Central High School

Weed and Soil Assessment for the Parking Lot “Islands” at Central High School

Jackie Doughty, Bridgette Minor, Akya Rice, Kendra Robinson, Jessica Scott, Lakita Scott and Kristy Tippey

ABSTRACT: Part A of this lab was performed to determine the extent to which an assortment of weeds have encroached in the parking lot “islands” at CHS since the school was built two years ago, when there were virtually no weeds present. Six quadrats of samples were collected and processed in the lab, after which a simple standard deviation analysis was performed. One quadrat proved difficult to sample because of an anthill on the curb (see picture below, on the right). The average mass (g) ratio of weeds to roots was 82g:22g or roughly 4:1. The data collected deviated significantly from the calculated mean, indicating that weeds have begun to take over sporadically in the parking lot islands, a fact that can be observed by observation: in some places the weed growth is extensive, while other spots are barren. Part B targeted the soil quality around three evergreen shrubs at varying levels of healthвЂ*one dead, one dying and one healthy plant. Plants were selected subjectively by visual appearance. Many evergreen trees and shrubs prefer a soil pH range of 5.0 to 6.0 (acidic), so it wasn’t surprising that the healthier evergreen appeared to enjoy a fairly low pH (5.0) along with a moderate level of phosphorous, low nitrogen, and high potassium. A possible fertilizer to encourage better, healthier growth for these evergreens should have at least a 5 : 10 : 3 NitrogenвЂ"PhosphorusвЂ"Potassium ratio.

Introduction

An ecology study was performed in two parts to determine both the extent of weed succession into the formerly weed-free landscaped parking lot islands and the soil quality around evergreen shrubs at varying levels of health. For part A (weed succession), it was predicted that there would be a significant amount of encroachment from a variety of weeds because of the time that has passed since the school was built; moreover, weeds typically move into available land, however pretty the original landscaping, because they’re always looking for new places to thrive. Also, it was assumed that the standard deviation would be relatively large because of the small number of samples taken from a larger area. An independent variable was established using six quadrats randomly placed in a 280m2 island after running a random number generator selected from the internet. The dependent variable was the mean quantities of weed “greens” and “roots” by mass (g) for the six samples. The size of the six quadrats and the random selection of the quadrat number were otherwise controlled.

Part B analyzed the effects of soil quality on the evergreen shrubs in the landscaped CHS parking lot islands. Plants need an assortment of minerals from the soil to grow and develop at optimal health. Minerals like nitrogen, phosphorus, and potassium are essential, and can be found in most fertilizers. This lab was performed to compare the quality of soil that produced a healthy plant vs. the soil around a dying and a dead plant. It was predicted that the soil quality itself might be affecting the health of these plants. Good health is predicted to require a pH level of around 5 (somewhat acidic), and trace amounts of nitrogen, phosphorus and potassium. The independent variable was the soil collected from the ground around three different plants. The dependent variable was the mineral levels contained in the soil.

Materials and Methods

Part A: To begin this lab a random number generator was accessed from the internet to select the six quadrat placements from the 280 possibilities. The parking lot island was measured and marked with chalk to determine the exact placement of each square meter quadrat. Weeds and roots were then collected from these six quadrats with scoopulas and bare hands providing the tools. The six samples were transported upstairs to the lab, where the weed “greens” were separated from the “roots” to create two different clusters of weed mass. Each cluster was weighed on a balance and the respective masses recorded for analysis. The average (mean) mass of weed and roots was calculated for a composite of all 6 quadrats put together. Using the given formula, standard deviation was calculated:

Note that X equals the measured value, equals the mean of all the samples and N equals the degrees of freedom (total number of samples minus one).

Part B: Three plantsвЂ*one dead, one dying, and one healthyвЂ*were located inside the island. Half cup samples of the soil from underneath each plant were then obtained using the scoopula and a Styrofoam cup. Back in the lab, 4mL of pH indicator was poured into a test tube. Three scoops of soil (0.5g each) were then mixed with the pH indicator for 10 minutes. The pH level was recorded. For the phosphorus test, a test tube was filled with 6mL of extracting solution. Three scoops of soil (again, 0.5g) were mixed with an indicator for 1 minute. Clear liquid appeared above the soil as a result. A pipet was used to transfer 3mL of the clear liquid. Six drops of phosphorus indicator were then added and mixed along with one phosphorous test tablet. The reaction color was compared to a color chart and recorded. For nitrogen, a test tube was filled with 7mL of nitrogen extracting solution and two measured samples of soil (0.5g each). These were both mixed. After the soil had settled, approximately 3mL of clear solution was extracted and placed into a second test tube. Two half-scoops of soil (about 0.25g each) were added to the second tube along with nitrogen indicator, then they were mixed. The colors of the reaction product and the nitrogen color chart were compared and recorded. A test tube filled with 7mL of potassium extracting solution and four scoops of soil (0.5g each) were mixed to begin the final test. A clean pipet transferred 5mL of clear supernatant to a second clean test tube. One potassium indicator tablet was added to the clear liquid. Last, potassium test solution was added two drops a time. When the color changed from purple to blue, the potassium test was complete and the results were recorded from comparison with a potassium “end point” color chart.

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