If you want to replicate our experiment, just follow these guidelines:

            To begin, we took a series of 20 soil samples 15 cm in length throughout the backwoods of Roland Park Country School using a soil core sampler that was about 2.45 cm in diameter. Five samples were taken from each of the 4 microclimates, measuring approximately 20 meters by 20 meters in area, which were determined in a previous biota survey experiment by the ESSRE program in Baltimore, Maryland. These samples included soil from the same quadrants from which the highest and lowest levels of aluminum were found during the preliminary biota survey. In microclimates 1 and 2, one sample was taken from quadrants one, three and four, and two from quadrant two. In microclimates 3 and 4, one sample was taken from quadrants one, two and three, and two samples were taken from quadrant four.  As we extracted the samples we recorded which microclimate and which quadrant the sample was taken from.  We then took the samples back to the lab and began aluminum, pH, and soil texture testing. To test for both aluminum and pH, we used a LaMotte STH Series soil test kit. To do the aluminum test, we used a14 ml sample of a 3% acetic acid, 10% sodium acetate soil solution and titrated a 5 ml (by volume) soil sample using a 99% isopropanol 0.1% hematein solution. After one minute, the color was compared to a chart and determined to be either Very Low, Low, Medium, High, or Very High. Ordinals from 1-5 were assigned, 1 being Very Low and 5 being Very High, and then recorded in data charts. To perform the pH tests, we used a 10 ml test tube with 1/3 soil and 2/3 Model Demineralizer to titrate the soil sample using a 0.008% polycrylamide solution. We put 1 ml of the solution (once it had settled) into the large depression of a spot plate, and another ml into the other large depression on the plate. We added two drops of a 28% ethanol, 2% methanol, <0.1% bromythol blue solution to one of the samples on the spot plate and compared the resulting color reaction against a color chart. We chose the narrow range indicator (either Bromcresol Green, Chlorphenol Red, Bromthymol Blue, Phenol Red, or Thymol Blue) and added two drops to the second sample on the spot plate. We compared the color reaction against a color chart. Finally, with the remaining soil we determined the percentages of sand, clay and silt in each sample. To do this, we put the soil in a jar with a flat bottom and added water up to one inch from the top of the jar. We put phosphate based detergent into a micropipette (two inches) and added that to the jar with the soil and water. After shaking vigorously for approximately one minute, we allowed the soil to settle. We measured the height of the entire column of soil, and then measured the heights of the columns of sand and soil. We used these heights to determine the percentages of sand and silt in each sample, and subtracted from 100 to find the percentage of clay.