问题
问答题 简答题
什么叫土壤自净？土壤被污染后其微生物群落有什么变化？
答案
参考答案：
土壤对施入其中的一定负荷的有机物或有机污染物具有吸附和生物降解能力，通过各种物理、生化过程自动分解污染物使土壤恢复到原有水平的净化过程，称为土壤自净。
土壤被污染后，土壤的微生物区系和数量发生改变，并诱导产生分解各种污染物的微生物新品种。
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什么叫土壤自净？土壤被污染后其微生物群落有什么变化？
参考答案：
土壤对施入其中的一定负荷的有机物或有机污染物具有吸附和生物降解能力，通过各种物理、生化过程自动分解污染物使土壤恢复到原有水平的净化过程，称为土壤自净。
土壤被污染后，土壤的微生物区系和数量发生改变，并诱导产生分解各种污染物的微生物新品种。
阅读下面短文，从所给单词中选出适当的词，并用其正确的语言形式填在标有题号的空白处，使语意通顺、完整。（每空一词且每个单词只能用一次）
 Carrots(胡萝卜) are grown on farms and in small family gardens all over the world. They are easy to _小题1:___ and easy to harvest(收获). They have a good __小题2:_. When people think about carrots, they 小题3:think they are a kind of long, thin, orange-colored vegetable. In _小题4:_, carrots are in many different sizes and shapes. And not all carrots are __小题5:_. Carrots should be grown in a _小题6:_ that does not have water for a long time. The earth also should not be too hard. To ___小题7:__ your carrot garden, dig up the earth and turn it over(翻土). Weather, soil condition(土壤状况), __小题8:__ time affect(影响) the taste of carrots. Warm days and __小题9:_ nights are the best time to grow great delicious carrots. The best way to decide if a carrot is ready to be harvested is by its color. Usually, the __小题10:__the color is, the better the taste is. Most people do not know that carrots can be grown __小题11:__ the winter months. If the winter is not cold __小题12:_ to freeze the ground, you can grow carrots the same way __小题13: you do during the summer months. Carrots are prepared and __小题14:_ in many different ways. They are cut into thin pieces and cooked with other _小题15:_ or meat. Or, they are washed, and eaten just as they come out of the ground. |