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Science project experiments on soil in relation to plants.
Relation of Soil to Plants- Science Project Idea
Since the amount of moisture in the soil has a great effect upon the growth of plants one important problem is: how the water-holding power of the soil may be increased.As the project is further analyzed it will be seen that other problems will be those concerned with what plants take from the soil, how these substances may be returned to the soil, how materials are taken from the soil and what the plant does with this material. How the water-holding power of the soil may be increased.We all know from observation that the growth of plants depends upon their being able to get sufficient water from the soil.How does grass appear during a prolonged dry period in summer?How may lawns and parks be kept green during such a time?We may water a small garden by the use of a hose, but such a means of supplying water to a large field is impossible.Therefore, any method by which the water-holding power of soil may be improved is very important. The water which is taken from the soil by plants may have two sources.It may be from water which has recently fallen as rain or it may be from water which has come up through the soil from below.A hole dug in the soil during dry weather will show that the upper part of the soil is dry and that the lower part is moist.If you lift either a board or a stone which has been undisturbed for a considerable time, what is the condition of the soil beneath it? What is the condition of the soil under a layer of leaves or straw which has been lying in one place for a long time? During dry weather lay a board on freshly cultivated earth in the garden, and in a few days compare the appearance of the surrounding soil with that under the board.All of these observations indicate that the water which is coming from below is escaping by evaporation at the surface and that the loss may be prevented by a covering of some kind.Sometimes such a covering is provided by a layer of leaves called a leaf mulch.But usually such a method cannot be employed very extensively.It has been found that hoeing or "cultivating" by making a mulch of dry soil prevents to a great extent this escape of water at the surface.This is because the small capillary spaces through which the water has been coming from below are broken up.One of the reasons, therefore, for frequent hoeing of a garden or cultivating of a field of corn is to prevent the loss of moisture from the surface of the soil.The power of different kinds of soils to absorb water from below may be illustrated by the following experiment.
Soil Water Loss Science Experiment Over the bottom of each of four or five glass tubes having a diameter of one or two inches, tie a piece of cheesecloth.Fill the different tubes with the following kinds of soil: coarse sand, fine sand, loam, and clay.Place the bottoms of the tubes in a vessel of water, and support them so that they will stand upright.After a day examine the tubes and draw conclusions. The finer the soil the smaller are the openings through which the water passes.How does this experiment help you to explain the effectiveness of the loose soil mulch?How does it explain the fact that seeds will grow better if the earth is pushed down firmly around them? The power of soils to hold the rain which falls upon them is shown by the following experiment.
Soil Water Loss Science Experiment II Into four funnels in each of which has been placed filter paper, put equal amounts of different soils: coarse sand, fine sand, loam, and clay.Pour into the funnels equal amounts of water.Catch the water that runs through in measuring glasses.After pouring the water through several times, note the amount of water that runs through each and draw your conclusions as to the conditions which make soils good holders of water.Suggest how the ability of the soil of a garden to hold moisture may be increased.
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