Study the experimental setups illustrated by diagrams I and II below and use them to answer questions (a) – (e)
(a) State the major differences between the experimental set-ups illustrated by diagrams I and Il.
(b) State the aim of the experiment being demonstrated as illustrated in diagrams I and Il.
(c)(i) What will happen to the lime water at the end of the experiment illustrated by diagrams I and II
(ii) Give reason(s) for your answer in (c)(i).
(d) What conclusion could be derived from the experiment?
(e) Explain three ways in which your conclusion in (d) is important to the soil.
Explanation
(a) The difference between the diagrams I and Il illustrated in the experimental set-up is that I contained a bag of fresh soil while Il contained a bag of heated soil.
(b) The aim of the experimental set -up illustrated by the diagrams was to show the presence of living organisms in the soil.
(c)(i) According to the aim of the experiments, there is líkely to be a change of the lime solution in I, (the lime solution will turn milky, while in ll, the solution remains clear)
(ii) Reason: The turning to the milky state by lime solution in l will occur as a result of the production of carbon dioxide by the living organisms in the soil sample while in ll, no carbon dioxide Is produced because the soil sample had been heated and hence the living organisms in it might have been killed.
(d) Based on (c), the conclusion of the experimental set-up is the presence of living organisms in the soil.
(e) Living organisms are important in the soil because they are involved in nitrogen fixation, aid decomposition of organic material, improve soil structure, assist in the addition of organic matter, improve soil aeration and improve soil water percolation.