农科英语Unit-7-Rice-ecosystems-in-Asia课件.ppt

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1、Unit 7Rice ecosystems in Asia Unlike many other crops，rice is grown in diverse land and water management systems.Therefore，tillage practices for land preparation in rice vary considerably starting with the cultivation practicesThe cultivation practices for rice differ with the rice ecosystems and ar

2、e broadly categorized as follows：Words to remember 1、tillage tld n.耕作，耕种耕作，耕种 tillage practices：耕作方式耕作方式2、land preparation 农学农学 整地整地3、cultivation kltven n.培养；耕作；耕种培养；耕作；耕种 cultivation practices：栽培方式栽培方式4、rice ecosystem：水稻生态系统水稻生态系统 Irrigated rice ecosystems are those areas that have bunded,puddle fi

3、elds with assured irrigation for one or more crops per yearThis ecosystem，which is concentrated mostly in the humid and subhumid subtropics,accounts for about 80 million ha(55%)of the harvested rice area and contributes 76%of global rice production,with average yields varying from 3 to 9 t ha-1.Irri

4、gated rice ecosystemsWords to remember 5、irrigate rget vt.灌溉；冲洗灌溉；冲洗6、irrigation renn.灌溉灌溉 7、bund bnd n.堤岸；码头堤岸；码头8、puddle pd()l n.水坑，水道；水坑，水道；9、humid hjumd adj.潮湿的；湿润的；潮湿的；湿润的；10、subhumid sbhju:mid adj.半湿润气候的半湿润气候的11、subtropics,sbtrpks n.地理地理 亚热带亚热带There are three rice environments in this ecosyste

5、m,namely,i.Irrigated with favourable temperature,ii.Irrigated with unfavourable temperature-tropical zone andiii.Irrigated with unfavourable temperature-temperate zoneWords to remember 12、favourable temperature:适宜温度适宜温度13、unfavourable temperature：不适宜温度不适宜温度14、tropical trpkladj.热带的热带的15、zone zonn.地带地

6、带16、temperate temp()rt adj.温和的；适度的温和的；适度的 tropical zone：热带热带 temperate zone：温带：温带 Improved rice cultivars that have been developed for irrigated rice lands are of short duration and are responsive to nitrogen fertilizer,and incorporate resistance to several biological stresses and some tolerance to

7、adverse soils.It is characterized by high cropping intensity and intensive use of agrochemicalsWords to remember 17、duration durenn.生育期，持续的时间生育期，持续的时间18、nitrogen fertilizer：氮肥：氮肥19、biological stress：生物逆境：生物逆境20、cropping intensity：种植密度种植密度21、agrochemical ,rokmkln.农用化学品农用化学品 Production constraints in

8、low(1ess than 3t ha-1)and medium yield(3-5t ha-1)areas are delayed plantings,shortage of labour,use of low to medium potential varieties,low input rates,poor input management,poor weed management,inadequate water supply,unavailability of irrigation at one or more critical stage,salinity/alkalinity p

9、roblem;associated poor drain-age and environmental stresses.Words to remember 22、constraint knstrent n.约束；限制约束；限制23、salinity：slntin.盐度；盐分；盐性盐度；盐分；盐性24、alkalinity,lklntin.碱度；碱性碱度；碱性25、drainage drendn.排水；排水系统排水；排水系统 Problems associated with high production(more than 5t ha-1)areas are yield instability

10、 due to pests,multiple cropping systems-delaying transplanting and environmental degradation.Words to remember 26、instability,nstbltin.不稳定，基础薄弱不稳定，基础薄弱27、multiple cropping systems：多熟制种植多熟制种植28、transplanting：移栽移栽 mechanical transplanting 机械化移栽机械化移栽 Rain fed lowland rice grows in budded fields that ar

11、e flooded for at least part of the cropping season to water depths that do not exceed 50 cm for more than ten consecutive daysRain fed lowlands are characterized by lack of water control,with floods and drought being potential problems.About 40 million ha(25%)of the global rice area is rain fed,cont

12、ributing 18%of the total production.Rainfed lowland rice ecosystemsWords to remember 29、Rain fed lowland rice 雨养湿地水稻雨养湿地水稻30、consecutive knsekjtv adj.连贯的；连续不连贯的；连续不断的断的 Rainfall is often erratic,so that conditions are diverse and unpredictable.Typically，traditional photoperiod-sensitive cultivars,wh

13、ich do not respond to fertilizer，are grown.No water harvesting/conservation facilities are available on the farm and there is no irrigation water availableFive major environments have been identified within the rainfed lowland ecosystem.These areWords to remember 31、erratic rtkadj.不稳定的不稳定的32、photope

14、riod ftprd n.光周期光周期 photoperiod-sensitive cultivars 光周期敏感的品光周期敏感的品种种33、water harvesting：雨水收集：雨水收集i.Rainfed shallow favourable environments：No drought or waterloggingii.Rainfed shallow drought prone environments：These areas have frequent and severe water-deficit problems and are drought proneThe rain

15、y season may be short(90-100 days)as in central and eastern India or long with erratic distribution as in Bangladesh and Thailandiii.Rainfed shallow drought and submergence prone environment:Areas subjected to both drought and waterlogging.iv.Rainfed shallow submergence prone environments:Frequent s

16、hort-term flooding that may damage or destroy the crop.v.Rainfed medium deep rice environment:Water 25-30 cm deep may stand for a substantial period of growing season.Words to remember 34、waterloggingw:t,lgi n涝；水浸涝；水浸35、prone pronadj.有有倾向的，易于倾向的，易于的的36、submergencesbmdns n.下潜，淹没下潜，淹没 Of the 148 m.ha

17、total rice area,this ecosystem covers about 18 million hectares of which 64 per cent is located in Asia,25 per cent in Latin America and 11 per cent in Africa.However,the area of the upland rice ecosystem is much larger than the area under rice,because rice is grown in rotation with Other crops.Yiel

18、ds are typically 1 t ha-1.In Asia,most upland rice is grown on rolling and mountainous land with slopes varying from 0%to more than 30%.Upland rice ecosystemsWords to remember 37、rotation r()te()n n.轮作，循环，轮流轮作，循环，轮流38、rolling rl n.旋转；动摇旋转；动摇 adj.旋转的；起伏的；波动的旋转的；起伏的；波动的39、slope slp n.斜坡；倾斜；斜率；斜坡；倾斜；斜率

19、；Dry soil preparation and direct seeding in fields that are generally unbunded are characteristic of the upland rice ecosystem.Surface water does not accumulate for any significant time,although in some countries,such as in eastern India and Bangladesh,upland rice fields are frequently bunded to sav

20、e scarce water.Shifting cultivation in common in Indonesia,Laos,the PhiliPpines,northern Thailand and Vietnam.These are rainfed rice areas with bunded or unbunded fields.Soils are well drained and therefore no surface water accumulates.Words to remember 40、direct seeding：直播直播41、bunded-unbunded42、sur

21、face water：地表水地表水43、shifting cultivation：轮作耕种轮作耕种 Soils are low in fertility and weeds are a major constraint;in many regions soils tend to be acid.In the hilly regions,mono cropping of rice is practiced and it is detrimental to soil and environment.Four major rice environments identified are:i.Favo

22、urable uplands with long growing season,ii.Favourable environment with short growing season,iii.Unfavourable environment with long growing season andiv.Unfavourable environment with short growing season.Major constraints are drought,weeds,low rates of inputs,poor input management,poor soil fertility

23、 and environmental stresses.Words to remember 44、fertility ftlt n.多产；肥沃，肥力多产；肥沃，肥力 soil fertility:土壤肥力土壤肥力 45、hilly hili adj.丘陵的；多小山的；多坡的丘陵的；多小山的；多坡的46、mono adj 单的单的 mono croping：单一作物制单一作物制47、detrimental,detrment()l adj.不利的；有害的不利的；有害的48、growing season：生长季，生长期：生长季，生长期 Since water is the major constra

24、int in upland rice ecosystem,a major part of area under rainfed upland ecosystem is direct seeded,generally at the onset of rain.Most Of the crop establishment operations are done when temperatures are high(generally above 30)and days are long and despite low crop canopy PET（potential evapotranspira

25、tion）is quite high.This is called as Moist I period(rainfall is less than PET but more than 1/2 PET).After this period,heavy rains come and rainfall is more than PET;this period is called as Humid period.Words to remember 49、crop establishment：作物的种植：作物的种植50、canopy knpi n.天篷；华盖；天篷；华盖；51、potential eva

26、potranspiration：潜在蒸散：潜在蒸散量量。也称为可能蒸发量或大气蒸发能力，是指大片而均匀的自也称为可能蒸发量或大气蒸发能力，是指大片而均匀的自然表面在足够湿润条件下水体保持充分供应时的蒸散量。然表面在足够湿润条件下水体保持充分供应时的蒸散量。52、moist mst adj.潮湿的；多雨的潮湿的；多雨的n.潮湿潮湿53、humid hjumd adj.潮湿的；湿润的；潮湿的；湿润的；Humid period is again followed by Moist II period(rainfall is less than PET but more than 1/2 PET).D

27、uring this period，temperature is lower and days are shorter than during Moist I and humid periods About 13 million hectares are under deep water and tidal wetland rice,mostly in the back swamps of the flood plains and deltas and on the slopes of natural levees in South Asia These are the regions whe

28、re rice grows under rainfed dry land or shallow flooding conditions for 1-3 months and is then subjected to flooding with water depth of more than 50 cm for a month or longer.Deep water and tidal wet land rice ecosystemsWords to remember 54、tidal wetland rice 滩涂湿地水稻滩涂湿地水稻55、swamp swmpn.沼泽；湿地沼泽；湿地56、

29、flood plain：冲击平原：冲击平原57、deltas delt n.（河流的）三角洲（河流的）三角洲58、levee lev n.堤坝（码头）；堤坝（码头）；These areas are found in the river basins（盆盆地地）of Ganges(ndi:z n.恒恒 河河)and Brahmaputra(,br:mpju:tr,n.雅雅 鲁鲁 藏藏 布布 江江)in India and Bangladesh(,ba:glde,n.孟孟加加拉拉国国),the Irrawaddy(,irwdi,n.伊伊洛洛瓦瓦底底江江)in Myanmar(mjnm:,n.缅缅甸

30、甸,the Mekong（meik,n.湄湄公公河河）Delta of Vietnam(,vjetnm,越越 南南)and Cambodia(kmbudi,柬柬埔埔寨寨)and the Chao Pharaya（tauprai 湄湄 南南 河河）in Thailand(tailnd泰国泰国).When water levels are over 100 cm,the crop is known as floating rice,while Tidal wet-lands occur where water levels are fluctuating and are influenced by

31、 tide in coastal beltsFloating rice yields range from 0.5 to about 2.5 t ha-1,while deep water rice may produce up to 4 t ha-1.Despite these low yields,these flood-prone areas support over 100 million peopleThe major problems are rice is the only crop that is possible；traditional low yield potential

32、 varieties；deep flooding and droughts both are possible;variable flooding patterns;tidal wetlands are subjects to salinity and other soil stresses(acid，acid sulphate and peat soils);susceptibility to stem borer；no resistance available and nematode problem(ufra disease)Words to remember 59、sulphate slfet n.硫酸盐硫酸盐60、peat pitn.泥煤；泥炭块；泥炭色泥煤；泥炭块；泥炭色 泥炭土泥炭土:在某些河湖沉积低平原及山间谷地中，由于长在某些河湖沉积低平原及山间谷地中，由于长期积水，水生植被茂密，在缺氧情况下，大量分解不期积水，水生植被茂密，在缺氧情况下，大量分解不充分的植物残体积累并形成泥炭层的土壤。充分的植物残体积累并形成泥炭层的土壤。61、susceptibility s,septibiliti n.敏感性敏感性62、stem borer 螟虫螟虫63、nematode nemtd adj.线虫类的线虫类的n.线虫，线虫类线虫，线虫类