问题 问答题 论述题

论述微生物和农业生产的关系。

答案

参考答案:

有益作用:(1)提高土壤肥力;微生物促进有机物质的分化,农艺措施促进微生物的生长,大力发展的生物

菌肥(2)扩大肥源,能源;生物菌肥的开发,沼气的利用,能眼微生物是很有前景的开发项(3)促进作物生长,根际营养和共生营养;根际营养:根系分泌物——微生物——养分——植物生长;共生营养:形成根瘤或菌根,参与营养物质合成和运转(4)防治病虫杂草;微生物产生抑制或杀死植物病原菌的物质,用来防治病虫害,有些微生物寄生在杂草上,致使杂草死亡(5)改善饲料品质;微生物将秸秆等分解发酵,增加适口性,提高营养价值(6)进行环境保护;三废处理,有毒物质的微生物转化。

有害影响:有些微生物是动植物的致病菌,引起病害流行。有些微生物造成食品的腐败,甚至产生有毒物质(黄曲霉素),危害人类健康,造成损失。

解答题
单项选择题

Roger Federer Lights up the Arabian Night
罗杰·费德勒点亮阿拉伯之夜


Plenty of people will be glad Tim Henman was not here to trouble Roger Federer once more last night,as the seedings said he should have been.Popular with the expatriates though he may be,and capable of upsetting Federer though he undoubtedly is,there is nothing quite so stirring as seeing one of the most gifted world No l s of all in full cry.
Instead of struggling with his jinx player,Federer imposed a spell of his own.He beat Andrei Pavel,whom Henman beat in the Paris Masters final,by6-3,6-3,and strode the court like a ruler who knows his aura is expanding.
It carried the Swiss imperiously into a semi-finals of the Dubai Championships,where he will face Jarkko Nieminen.The Finn earned his place by defeating the Dutch No 8 seed Sjeng Schalken 6-3,6-3.
Federer insisted he was not at his best-"I haven’t wanted to chase the fines as much as I should,"he said.
Pavel was driven to distraction as it was.He had akeady lifted himself near the level he showed when he was in the top 20.But just when he looked as if he might prolong the second set, Federer struck.
He retrieved one ball from deep,outside the tramlines on the forehand side,turned and reached the next ball from short and outside the tramlines on the backhand side,and still somehow hit a controlled winner.It completed the decisive break of serve.
Pavel responded by launching a spare ball towards the sky and it landed on the whiskey tables in the lrish village below.The umpire uttered a code violation warning in little more than a whisper.It was as though he felt sympathy for the Romanian.
If Federer reaches tomorrow’s final he will play Spain’s Feliciano Lopez,whose Davis Cup debut came in the singles in the 2003 final in Melbourne,or Mikhail Youzhny,whose first Davis Cup experience was as a ball boy in the 1995 final in Moscow.
That spurred Youzhny to make a top-level breakthrough seven yearslater,and to develop perseverance which has been revealed this week in a 6-3,1-6,6-1 quarter-final win over Rafael Nadal yesterday in heat which would have made a camel protest,and in a recovery from two days’vomiting after eating Japanese seafood."My cap felt as if it weighed five kilos."he said.

From the opening paragraph,it can be inferred that______.

A.Tim Henman and Roger Federer were not in good terms
B.Roger Federer was hardly any match to Tim Henman
C.Tim Henman avoided meeting Roger Federer in the match
D.gifted world No ls are usually reduced to a state of tears when having lost a game