问题 问答题 简答题

为什么说砂土肥效快、后劲不足,而粘土肥效慢、但后劲稳长?

答案

参考答案:砂土砂粒含量高,粘粒含量低,有机质含量一般较低。粘土粘粒含量高,砂粒含量低,有机质含量也较高。砂土对外来养分的吸附保蓄能力较弱,而粘土对外来养分的吸附保蓄能力则较强。因此,当肥料进入砂土时,以可溶的、有效的形态存在的养分比例较高,被土壤吸附固定的比例较低,所以总的有效性高,肥效快。相反,当肥料进入粘土时,以可溶的、有效的形态存在的养分比例较低,被土壤吸附固定的比例较高,所以总的有效性较低,肥效慢。进入砂土的养分被植物吸收的快,同时被淋溶损失的也较快,肥效下降快,因此后劲不足。进入粘土的养分被植物吸收的慢,被淋溶损失的较慢,被吸附的养分会慢慢释放出来,因此后劲稳长。

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  How to make friends with people from a different culture? The rules are as follows:

Appreciate the person

Most Americans like to be recognized as individuals as someone special with unique, personalities. Therefore never say,“you are from America so I want to be your friend.” Also don’t imply that the reason why you approached them is that you wanted someone to practice your English with . That turns people off. Instead try saying,”“you seem like a real nice and interesting person and I would like to get to know you better .’ This way , they are much more inclined to be friendly because you see them as a three dimensional person and appreciate them for who they are in the inside . And by doing so , you not only learn about Americans and practice your English , but also gain a real friend in the process

Quit Calling Us Foreigners.

Please avoid calling a foreigner especially in his face . The word makes people feel like an outsider , and even unwelcome , suggesting separation and insurmountable difference , widening an already existing gap in the situation. When Americans travel , they rarely say,“I’m foreign to your place .” They tend to say ,”I’m new in town . I’m new here.” The reason is because new and unfamiliar things can become old and familiar. But can foreign things become native? You catch my drift.

Just Do It .

Some students like to be told about American culture but are less interested in spending the time and effort to actually experience it .As Americans always say ,“get your hands dirty.” You should have first hands on experience, or you will never really know anything.

Find that Common Language.

Now I just must stress the importance of finding a common language. By that I don’t mean English, Chinese , German ,French,etc. I mean finding something you have in common with another person on a spiritual and philosophical level: likes , dislikes, worldviews, ways of thinking and attitudes toward life. And to start , you must first enhance your knowledge of the particular culture from which your potential

小题1: The underlined sentence“get your hands dirty” means     .

A get involved   B talk about American culture    C star with dirty work   D Don’t wash your hands too often

小题2: Americans prefer to make friends with those who    .

A  avoid talking about their homeland     B  recognize their personalities

C  obey rules of communicating with friends   D  needn’t practice English while playing together

小题3:According to the passage , which of the following is friendly?

A   I am longing to make friends with an American.

B   This is my friend Tom , who is a foreigner.

C   There must be a gap between us in many things.

D   You ‘ve  got a great personality

小题4:  In the last paragraph , the author suggests we should   

A  Learn at least one foreign language well

Bfind common interests or opinions with our potential new friend

C make sure we can understand each other

D ask where our potential new friends come from