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Unit 1
basic parts of a plant a the root system, which is below the ground , and the shoot system above. Ò»Ö²Öê×î»ù±¾×é³É²¿·ÖÊǵØϸùϵͳºÍµØÉϾ¥ÏµÍ³
takes in, or absorbs, water and mineral from the soil through the root hairs, which are single cells near the tip of each root¸ùëÊÇ¿¿½ü¸ù¶¥¶ËµÄµ¥Ï¸°û£¬Ëü¿ÉÒÔ´ÓÍÁÈÀÖÐÎüÊÕË®·ÖºÍ¿óÎïÖÊ
addition, plants such as clover and Lucerne, known as ¡®legumes¡¯ have special bacteria which live on the roots. ÁíÍ⣬һЩ¶¹¿Æ×÷ÎÈçÈýÒ¶²ÝºÍÜÙÞ££¬ÓÐÌØÊâµÄ¼ÄÉúÔÚ¸ù²¿µÄϸ¾ú
important function is to enable water and mineral to pass up from the roots to the leaves and flowers.ÁíÒ»ÖÖÖØÒªµÄ¹¦ÄÜÊÇʹˮºÍ¿óÎïÖÊ´Ó¸ùÔËÊ䵽ҶƬºÍ»¨ÉÏ
main job is to make food for the plant by the process known as photosynthesis.ËüÃǵÄÖ÷ÒªÈÎÎñÊǹâºÏ×÷ÓÃΪ×÷ÎïÌṩӪÑø
from the soil and carbon dioxide from the air are converted into sugars and other carbohydrates.À´×ÔÍÁÈÀÖеÄË®ºÍÀ´×Ô´óÆøÖеĶþÑõ»¯Ì¼±»×ª±ä³ÉÌǺÍ̼ˮ»¯ºÏÎï
stamens produce the male sex cells, or spermatic, which are carried in the pollen grainsÐÛÈï²úÉúÐÛÐÔϸ°û»òÊÇÐÔæß×Ó£¬ËüÃDZ»»¨·ÛÁ£Ð¯´ø.
fruit, the ripened ovary of the flower, encloses the seeds and protects them while they are developing£¬¹ûʵ£¬»¨ÖгÉÊìµÄ×Ó·¿£¬°üΧ×ÅÖÖ×Ó£¬µ±ËüÃÇ·¢Óýʱºò²¢±£»¤ËüÃÇ
seed itself consists of an embryo and foodstoreÖÖ×ÓÊÇÓÉÅߺÍ.ÅßÈé¹¹³ÉµÄ
embryo is the part which will develop into anther plant and the foodstore is necessary to provide nourishment for the young plant while it is growing.ÅßÊÇÄÜ·¢Óý³ÉÁíÍâ×÷ÎïµÄÆ÷¹Ù£¬ÅßÈéÊÇΪ·¢ÓýÖеÄÓ×ÌåÌṩ±ØÒªµÄÓªÑø Unit 2
remain dormant, or in a resting state, if they are kept cool and dry.ÖÖ×ÓÔÚµÍκ͸ÉÔïÌõ¼þÏ£¬´¦ÓÚÐÝÃß״̬
the amount of moisture and the temperature level are right, the seeds germinate and start growing.µ±Î¶ȺÍʪ¶ÈÊÊÒËʱ£¬ÖÖ×Ó·¢Ñ¿²¢¿ªÊ¼Éú³¤
is because wet soils remain cold for a longer period of time than drier, well-drained soils.ÕâÊÇÒòΪʪµÄÍÁÈÀ±È¸ÉÔïµÄÅÅË®ºÃµÄÍÁÈÀ¸üÄܱ£³Ö¸ü³¤Ê±¼äµÄµÍÎÂ
seeds require very little oxygen in order to stay alive, but when they start to germinate they require more. ÖÖ×ÓÔÚÐÝÃß״̬ʱΪ±£³Ö»îÁ¦ÐèÒª½ÏÉÙo2£¬µ«µ±ËüÃÇ·¢Ñ¿Ê±ÐèÒª½Ï¶àµÄo2
the early stages of development the seedling depends entirely on the
foodstore in the seed but as soon as the first leaves are produced, it is able to manufacture food for itself.·¢ÓýÔçÆÚ£¬Ó×ÃçÍêÈ«ÒÀ¿¿ÖÖ×ÓÖеÄÅßÈ飬µ«ÊÇÒ»µ©µÚһƬ×ÓÒ¶²úÉú£¬Ëü¾ÍÄÜΪ×Ô¼ºÉú²úʳÎï
the process of pollination the pollen is carried by wind or insects from the stamens to the stigma of the carpel.´«²¥»¨·Û¹ý³ÌÖУ¬»¨·Û±»·ç»òÊÇÀ¥³æ´ÓÐÛÈï´«²¥£¬µ½´ÆÈïÖùÍ·ÉÏ
germinates on the stigma and grows down the style into the ovary, where fertilization takes place.ËüÔÚÖùÍ·ÉϲúÉú²¢ÔÚ×Ó·¿Öз¢Óý£¬½øÐÐÊܾ« Unit 3
material originates from dead plants and animals and material other than this are derived from rocks of various kinds. ÓлúÖÊ·¢Ô´ÓÚËÀµÄ¶¯Ö²Î¶ø¿óÎïÖÊÊÇÓëÖ®²»Í¬µÄ²»¾·Ö½â£¬À´Ô´ÓÚ²»Í¬ÖÖÀàµÄÑÒʯ
rocks are broken down into small particles by mechanical disintegration and chemical decomposition.ÕâЩÑÒʯͨ¹ýÎïÀíºÍ»¯Ñ§·Ö½â³ÉС¿ÅÁ£
arid regions weathering is mostly by physical means.ÔڸɺµµØÇø£¬·ç»¯Ö÷ÒªÓÉÓÚÎïÀíÒòËØ
in humid regions chemical processes of weathering are equally importantµ«ÊÇÔÚʪÈóµÄµØÇø£¬·çÊ´µÄ»¯Ñ§¹ý³ÌÊÇͬµÈÖØÒªµÄ.
, the insoluble mineral residues in the soils have less resemblance to the original rocks. Òò´Ë£¬ÍÁÈÀÖÐÄÑÒÔÈܽâµÄ²ÐÓà¿óÎïÖÊÓëÔʼµÄÑÒʯÎÞʲôÀàËÆ´¦
of them contain various proportions of sand, silt and clay and these varying proportions make up a soil¡¯s textural class.ÍÁÈÀÖ÷Òª°üÀ¨É³×Ó£¬·ÛÉ°£¬Õ³ÍÁ¡£¡£ËüÃDz»Í¬µÄ±ÈÀý¹¹³ÉÁËÍÁÈÀ²»Í¬µÄÖʵصȼ¶
principle classes in order of increasing fineness of material are sand, loamy sand, loamy, silt loamy, silty clay loam, clay loam, silt and clay.ÒÀÕÕ¿óÎïÖÊ´¿¶È˳ÐòÅÅÁÐÒÀ´ÎΪɳÍÁ£¬ÈÀÉ°ÍÁ£¬ÈÀÍÁ ·ÛÉ°ÍÁ£¬Õ³ÈÀÍÁ£¬·ÛÉ°ºÍÕ³ÍÁ is to say, smaller sized particles can react or combine with water,
nutrients and humus more sassily than larger sized particles.¾ÍÊÇ˵£¬Ð¡¿ÅÁ£ÓëË®£¬ÓªÑøºÍ¸¯Ö³Öʱȴó¿ÅÁ£¸üÈÝÒ×½áºÏ
from decomposed organic matter is vital to a soil as it makes a heavy soil lighter. À´Ô´ÓÚ¸¯ÀÃÓлúÎïÖʵĸ¯Ö³ÖÊ£¬¶ÔÍÁÈÀÖÁ¹ØÖØÒª£¬ÒòΪËüʹÍÁÈÀ±äµÄ¸üÊèËÉ Unit 4
2.The ease with which water san pass through a soil depends on the
proportions in it of coarse and fine particles such as sand and clay.Ë®·ÖÉøÈëÍÁÈÀµÄÈÝÒ׶ÈÒÀ¿¿ÍÁÈÀ´Öϸ±ÈÀý£¬ÀýÈçÉ°ÍÁºÍÕ³ÍÁ
10.Another advantage is that a well-drained soil will have enough air for aerobic bacteria to break down humus and so provide food for the plant.ÁíÒ»¸öÓŵãÊÇÅÅË®ºÜºÃµÄÍÁÈÀ»áÓÐ×ã¹»µÄ¿ÕÆø£¬ÎªºÃÑõµÄϸ¾úÈ¥·Ö½â¸¯Ö³ÖÊ£¬È»ºóΪ×÷ÎïÌṩӪÑø
12.Ditches can be cut at certain intervals between the crops.ÔÚ×÷ÎïÖ®¼ä¹µÇþ±»Çиî³ÉÌض¨µÄ¼ä¸ô
16.Porous drainage tiles may be laid in or on the land and these will help draw off the surplus water. ¶à¿×ÅÅË®¹Üƽ·ÅÈëµØÏ»òµØÃæÏ£¬ÕâÑù»áÓÐÖúÓڷŵô¶àÓàË®·Ö
17.The distance between the drains will depends on the level of the land, the permeability of the soil, and the amount of rainfall.ÅÅË®¼äµÄ¾àÀëÈ¡¾öÓÚÍÁµØµÄƽ̹³Ì¶È£¬ÍÁÈÀÉø͸ÐÔºÍÓêÁ¿µÄ¶àÉÙ
22.We should distinguish between the collection of water and its applicationÎÒÃÇÓ¦±æ±ðË®µÄ¼¯ºÏºÍËüµÄÀûÓÃÖ®¼ä¼ÓÒÔÇø±ð.
23.There are two main sources of irrigation water: surface water and ground water.ÓÐÁ½ÖÖÖ÷Òª µÄ¹à¸ÈË®×ÊÔ´£ºµØ±íË®ºÍµØÏÂË®
31.By this we mean the amount of water which is needed to bring the soil to full capacity.Òâ˼ ÊÇÐèÒªµÄË®µÄÁ¿ÊÇÄÜʹÍÁÈÀ´ïµ½³ä·ÖµÄµÄÊýÁ¿
32.It also depends on the type of crop, the stage of growth of the crop and the amount which it will use at that particular time.ËüҲȡ¾öÓÚ×÷ÎïµÄÀàÐÍ£¬×÷ÎïÉúÓýʱÆÚºÍËüÔÚÌØÊâʱÆÚµÄʹÓÃÁ¿
34.Most plants require larger quantities of water during the later stages than in the earlier stages.´ó²¿·Ö×÷ÎïÔÚºóÆÚ±ÈÇ°ÆÚÐèÒª¸ü´óÁ¿µÄË® Unit 5
8.Finally, it makes up for the plant nutrients which have been removed by crops or lost by leaching and soil erosion.×îÖÕ£¬ËüÃÖ²¹ÁË×÷ÎïÎüÊÕ£¬ÁÜÈÜÍÁÈÀÇÖÊ´ËùÁ÷ʧµÄÓªÑø
14.So, they maybe grouped as nitrogenous fertilizers, phosphatic
fertilizers, potassic fertilizers and so on.Òò´Ë£¬ËüÃDZ»·ÖΪµª·Ê£¬Á×·Ê £¬¼Ø·ÊµÈ
15.The most commonly used fertilizer which contains nitrogen is ammonium sulphate, which is made from ammonia and sulphuric acid, and which
contains 21% nitrogenʹÓÃ×îÆÕ±éµÄ·ÊÁÏÊǺ¬µªµÄ£¬Ö÷ÒªÓÐÁòËá淋ȣ¬ËüÓÉ°±ºÍÁòËá×é³É£¬ÆäÖꬵªÁ¿°Ù·Ö¶þʮһ.
16.This element encourages rapid vegetative growth and gives plants a healthy green colour.Õâ¸öÒªËشٽø×÷Îï¿ìËÙÉú³¤²¢¸ø×÷ÎïÒ»¸ö½¡¿µµÄÂÌÉ«
19.Phosphorous stimulates the formation of a plant's root, and promotes fruit and seed production.Á״̼¤¸ùϵÐγɣ¬´Ù½ø½á¹ûºÍÖÖ×Ó²úÁ¿
21.finally, wherever high crop yields are expected, potash is used together with nitrogen and phosphorous.×îÖÕ£¬ÎÞÂÛÔÚÄĸ߲úÁ¿¶¼ÊDZ»ÆÚÍûµÄ£¬Í¨¹ýkÓën,p»ìºÏʹÓÃ
23.This help plant to withstand mechanical damage such as broken branches and torn ÓÐÖúÓÚ×÷ÎïµÖ¿¹»úеÉ˺¦£¬ÀýÈç²ÐÖ¦°ÜÒ¶
27.It is usually supplied in the form of muriate of potash (potassium chloride), which contains 50 to 60% potassium oxide (K2O) and sulphate of potash (potassium sulphate).Ëü×ÜÊÇÒÔkµÄ»¯ºÏÎïÐÎʽ±»Ê¹Ó㬰üÀ¨°Ù·ÖÎåÊ®µ½60µÄk2oºÍk2so4
32.If a soil is very acid, with a pH value of less than , lime can be added to correct this acidity.Èç¹ûÍÁÈÀ¼«ËáÐÔ£¬phСÓÚ5£¬Ê¯»ÒÄܹ»¸ÄÉÆÍÁÈÀµÄËáÐÔ 35.Nitrogen, phosphorous and potassium are more easily available in a well-limed soil than in an acid soil.µªÁ×¼ØÔÚÓÃʯ»Ò´¦ÀíµÄÍÁÈÀÖбÈÔÚËáÐÔµÄÍÁÈÀÖиüÈÝÒ×±»ÀûÓà Unit 6
1 In crop production the control of weeds, diseases and pests is essential to obtain high yields.ÔӲݺͳ溦µÄ¿ØÖƶÔÓÚ»ñµÃ¸ß²úÁ¿ÊÇÓбØÒªµÄ
5 Weeds reduce crop yields on account of the fact that they compete with crops for water.ÔÓ²Ýʹ×÷Îï²úÁ¿½µµÍµÄÔÒòÊÇËüÓë×÷ÎᄎÕùË®·Ö£¬ÓªÑø £¬¹âÕÕ
7 Most weeds are aggressive and invasive, they grow quickly and spread far, and so are difficult to get rid of.´ó¶àÊýÔÓ²ÝÊÇÓоºÕù ÐÔºÍÇÖº¦ÐԵģ¬ËüÃÇÉú³¤Ñ¸ËÙ£¬´«²¥µÄÔ¶£¬Òò´ËºÜÄÑ°ÚÍÑ
8 One recommended way of eradicating many persistent weeds is first to plough up the roots and underground parts of the plant.Ò»ÖÖÖµµÃÍƼöµÄ¸ù³ý¶àÄêÉúÔӲݵķ½·¨ÊÇÊ×ÏȸùϵºÍ×÷ÎïµØϲ¿·Ö
11 Weeds may also be killed by means of chemicals which have the collective name of herbicides.ÔÓ²ÝÒ²¿ÉÒÔ±»³ÆΪ³ý²Ý¼ÁµÄ»¯Ñ§Ò©¼ÁɱËÀ
17 They must be used extremely carefully for the simple reason that they will eradicate all plants on contact-which includes the crop itself.ËüÃÇÔÚʹÓõÄʱºò±ØÐëÏ൱СÐÄ£¬ÔÒòºÜ¼òµ¥¾ÍÊÇËüÃÇ»á¸ù³ýËùÓÐÓëÖ®½Ó´¥µÄÖ²Îï°üÀ¨×÷Îï±¾Éí
18 They are usually used before sowing or before the emergence of the crop itself.ËüÃÇ×ÜÊDZ»ÓÃÓÚ²¥ÖÖÇ°»ò×÷Îï³öÍÁÇ°
23 Micro-organisms are reproduced and spread by minute bodies such as spores, fungi and bacteria.΢ÉúÎïͨ¹ýÑ¿æߣ¬Õæ¾ú£¬Ï¸¾úµÈ΢СÎïÌå½øÐз±Ö³ºÍÀ©É¢
25 It is very difficult to kill the fungi and bacteria, or to make the virus which is inside the host plant inactiveÏûÃðÕæ¾úºÍϸ¾ú»òÊÇʹ¼ÄÉúÔÚ¼ÄÖ÷Öв»»îÔ¾µÄ²¡¶¾²»´«²¥²¡¶¾ÊǷdz£À§ÄѵÄ.
26 But the evolution of plant varieties which can resist disease has
completely changed methods of disease controlµ«ÊÇÄܹ»µÖ¿¹²¡º¦µÄ×÷ÎïÖÖÀàµÄ½ø»¯£¬ÒѾÍêÈ«¸Ä±äÁ˲¡º¦¿ØÖƵķ½·¨
36 One way is to use chemicals that easily change into a gas or vapour, which enter the soil and kill the harmful organisms. Ò»ÖÖ·½·¨ÊÇʹÓÃÈÝÒ×±ä³ÉÆøÌå»òÑÌÎí×´µÄ»¯Ñ§Ò©¼ÁÕâÑù¾ÍÄܽøÈëÍÁÈÀÏûÃðÓк¦ÉúÎïÌå
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