VOA慢速英语 2007 0403a(在线收听) |
This is the VOA Special English Agriculture Report. Mulching is one of the best things people can do for their plants. Mulch not only protects the soil against wind and water damage. It also helps keep the soil from getting dry, and reduces the need for watering plants. It also limits temperature changes in the soil. And it stops unwanted plants, or weeds, from growing. Organic mulch improves the condition of soil. As the mulch breaks down, it provides material which keeps the soil from getting hard. This improves the growth of roots and increases the movement of water through the soil. It also improves the ability of the soil to hold water. Organic mulch contains nutrients for plants. It also provides a good environment for earthworms and other helpful organisms in the soil. The United States Department of Agriculture says it is easy to find organic mulch materials. Cut-up leaves and small pieces of tree bark can be used. Grass cuttings are also a good mulch for plants. Mulch from newspapers works well in controlling weeds. The best time to add mulch depends on your goal. Mulch provides a thick barrier between the soil and the air. This helps to reduce temperature changes in the soil. As a result, mulched soil will be cooler than other soil in the summer. Mulched areas usually warm up more slowly in the spring and cool down slowly in autumn. In winter, the mulched soil may not freeze as deeply as other soil. Mulch used to help moderate the effects of winter weather can be added late in autumn. The best time is after the ground has frozen, but before the coldest weather arrives. Spreading mulch before the ground has frozen may attract small animals searching for a warm place to spend the winter. Delaying the spreading should prevent this problem. The animals will probably find another place to live. And that's the VOA Special English Agriculture Report, written by George Grow. Your can download transcripts and audio files of our reports at voaspecialenglish.com. I'm Steve Ember. |
原文地址:http://www.tingroom.com/voa/2007/4/42521.html |