问题 问答题 简答题

试述小麦抽穗结实期的田间管理技术措施。

答案

参考答案:抽穗结实阶段1、主攻方向小麦抽穗后根、茎、叶的生长基本停止,进入以生殖生长为主阶段,主要目标是养根、保叶、防止早衰和贪青,抗灾、防病虫,延长上部叶片的功能期,保持较高的光合速率,增粒增粒重,丰产丰收。2、栽培技术(1)排水降湿与后期灌溉南方麦区大部分地区小麦生育后期降水量大大超过小麦生理需水量,土壤水分饱和,麦株生理缺水,造成高温逼熟,同时也加重了病害。因此,要加强疏通排水沟,做到沟底不积水,降低土壤湿度,防止受渍使根系早衰。北方麦区和南方麦区部分地区,在小麦生育后期降水偏少,甚至有干热风危害,需合理灌溉,后期灌水主要在于防止早衰,保持叶片光合强度,有利于碳水化合物的合成和运转,对促进子粒充分灌浆,增加粒重有显著作用。灌水时间、数量因地制宜,以保持土壤田间最大持水量达70-75%为宜。值得注意的是,后期灌溉不宜太晚。灌水时应注意天气变化,掌握小水轻浇,速灌速排,畦面不积水,干热风到来之前灌好,有风不灌,雨前停灌,避免灌后遇雨造成倒伏。(2)根外追肥小麦抽穗开花至成熟期间仍需吸收一定的N、P营养,灌浆初期应用磷酸二氢钾、尿素单喷或混合喷施可以延长后期叶片的功能,提高光合速率,促进籽粒灌浆增重,并提高籽粒蛋白质含量,磷酸二氢钾浓度为0.2%-0.3%、尿素浓度为1%-2%,溶液用量为750kg/公顷左右。近年来生产上结合后期病虫防治喷施生长调节剂类产品也起到一定增加粒重的作用。(3)防治病虫小麦生育后期是粘虫、蚜虫、白粉病、锈病、赤霉病大量发生的时期,对千粒重和产量影响很大,除做好选用抗病虫品种,田间开沟排水、降湿等农业综合措施防治外,必须加强病虫预测预报,及时采取药剂防治措施。

单项选择题
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完形填空。

     Most of us can remember the days when we didn't use e-mail as an everyday vehicle for communication.
Slowly but surely, it crept (慢慢移动) into   1   . E-mail is a   2   tool for college students at any level. It's
available 24 hours a day,7 days a week and   3   at holidays. Most universities assign students an account
entrance,   4   there is usually not even an option (选择) involved.
     You can do everything from consulting on homework and projects,   5   classmates, family and friends,
and getting daily new services to  6   you informed of world  7   . But, what are the  8  ? E-mail can be e-jail.
You might   9   hours writing and replying to e-mails  10   you should be busy with the books for an upcoming
exam. 
  11   ,you might be signed up for so many daily services,   12   horoscopes (占星术), new services, or
personals, that your mailbox is so   13   "junk mail",that finding the  14  e-mails through your box might take
hours.
      If you're a student,  15   is precious. Create and organize your e-mail folders into important school-related
mail, correspondence (通信)with friends and family, and a folder for jokes, horoscopes and other new services. 
  16   put the mail into the proper folders first, and when you've finished, head for the important school-related
folder first. Respond to the most important e-mails first and,   17   you have time, you can get to the others. 
       18  your friends from forwarding those tiresome jokes, tiresome quizzes, and chain mails. The minute you 
  19   you've got one, delete it   20   so you won't be tempted to read it.

( )1. A. the lives          
( )2. A. valuable           
( )3. A. even               
( )4. A. but                
( )5. A. keeping touch with 
( )6. A.keeping             
( )7. A. accidents          
( )8. A. advantages  takes  
( )9. A. spend              
( )10. A. for               
( )11. A. Otherwise       
( )12. A. such as          
( )13. A. full up with      
( )14. A. important         
( )15. A.money              
( )16. A.Sometimes         
( )17. A. if                
( )18. A. Encourage         
( )19. A.examine            
( )20. A.later            

B. life              
B. changeable        
B. still             
B. so                
B. getting touched to
B. keep              
B. incidents         
B. mistakes          
B. cost              
B. because           
B. Or                
B. such like         
B. full              
B. necessary         
B. mark              
B. Always            
B. although          
B. Watch             
B. check up          
B. immediately       
C. our lives         
C. favorable         
C. ever              
C. because           
C. losing touch with 
C. leaving           
C. events            
C. wrongs            
C. take              
C. since             
C. But               
C. for example       
C. filled up with    
C. practical         
C. grade             
C. Almost          
C. since           
C. Discourage        
C. find              
C. after           
D. us life               
D. usable                
D. yet                   
D. except that           
D. keeping in touch with 
D. leave                 
D. things                
D. disadvantages         
D. pay                   
D. when                  
D. However               
D. so as                 
D. fill with             
D. possible              
D. time                  
D. Usually               
D. because               
D. Refuse                
D. realize               
D. soon