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Show 1= ^^ ^ Use a clay loam soil if possible. But any good loam that you can get from a flowerbed or from a grassed roadside will do. Work slightly damp soil into a good tilth by pressing it through a wide- mesh sieve. Fill two beakers with openings at the bottom about two- thirds full of the soil. Leave one sample bare and cover the other with a layer of grass clippings, clipped straw, or fine shavings. Place a glass jar below each beaker. Pour water on the soil from a height of about 1 foot. Use a sprinkler or a can with holes in the bottom. Make the holes large enough to give a heavy sprinkling of water. Compare the amount of water that drips through the beakers into the jars. INTERPRETATION Water impact puddles the bare soil, clogging the surface pores. The result is that the soil cannot take in water. In a field, most of the water would run off rather than enter the soil. By protecting the pores at the surface of the soil with a mulch, water enters and moves down through the soil. A mulch, such as straw, grass, or shavings, pre- Cultivation on ridge planting of corn in soybean residue. Soybean residue acts as a mulch to protect the soil from erosion. 14 |