Appu’s father wants to grow onions on his farm. Appu’s farm has three kinds of soil in different areas. Onions grow best in loamy soil. So, Appu decided to measure the percolation rate for the three different soils on his farm. He used a device like the one shown below. Appu, however, forgot and added different quantities of water while testing the percolation rate for each soil. He measured the time taken for all the water added into the device to percolate and tabulated them.
Soil NumberQuantity of water addedTime taken to percolate completelySoil 1500 mL300 minutesSoil 2200 mL30 minutesSoil 3100 mL300 minutes
Which soil must be used to grow onions?
Soil 1
Different types of soil have different percolation rates. Sandy soils have the highest while clayey has the lowest. Loamy has a percolation rate in between. (Remember that larger the soil particle size, higher the water percolation rate).
Percolation rate = Anount of water percolated(mL)Time taken(minutes)
Using this formula we can find the percolation rates as below:
Soil NumberQuantity of water addedTime taken to percolate completelyPercolation rateSoil 1500 mL300 minutes500mL300min=1.67mL/minSoil 2200 mL30 minutes200mL30min=6.67mL/minSoil 3100 mL300 minutes100mL300min=0.33mL/min
Thus the order of percolation rate is:
Soil 2>Soil 1>Soil 3
As stated before, loamy soils have percolation rates in between sandy and clayey soils. Thus, Soil 1 is loamy and is suitable for growing onions.