VOA慢速英语 自己为花园制作堆肥

　　For example, the New York State Department of Environmental Conservation lists some dos and don'ts of composting on its Web site.

　　Do add lime, small amounts of wood ashes or crushed eggshells to the compost pile. This will neutralize acids which may form and cause a bad smell.

　　Do mix grass cuttings with other wastes to loosen them up. And do keep the compost pile damp, especially during dry periods.

　　Do not use unfinished compost. It will rob plants of nitrogen instead of acting as a fertilizer.

　　Do not compost weedy plants with lots of seeds. Some seeds will not be killed during the natural heating process in composting.

　　Do not add meat, fish bones or fatty food wastes to the compost mixture. Protein materials do not readily decompose and they will bring animals.

　　And, finally, do not add diseased vegetable plants to the pile if the compost will be used on a vegetable garden. Disease organisms may reappear if you do.

　　Compost differs from mulch but it can be used as mulch. Mulch is placed on top of soil to protect it. Mulch is generally used to a height of about ten centimeters. But finer materials such as compost should only be two and a half to seven and a half centimeters high. Too much mulch can restrict oxygen and water flow.