Unit7亚洲水稻生态系统.ppt

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 a

2、re broadly categorized as follows：,Words to remember,1、tillage tld n. 耕作，耕种 tillage practices：耕作方式 2、land preparation 农学 整地 3、cultivation kltven n. 培养；耕作；耕种 cultivation practices：栽培方式 4、rice ecosystem：水稻生态系统,Irrigated rice ecosystems are those areas that have bunded, puddle fields with assured irrig

3、ation 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.,Irrigated rice ecosys

4、tems,Words to remember,5、irrigate rget vt. 灌溉；冲洗 6、irrigation renn. 灌溉 7、bund bnd n. 堤岸；码头 8、puddle pd()l n. 水坑，水道； 9、humid hjumd adj. 潮湿的；湿润的； 10、subhumid sbhju:mid adj.半湿润气候的 11、subtropics ,sbtrpks n. 地理 亚热带,There are three rice environments in this ecosystem, namely, i. Irrigated with favourable

5、temperature, ii. Irrigated with unfavourable temperature-tropical zone and iii.Irrigated with unfavourable temperature-temperate zone,Words to remember,12、favourable temperature:适宜温度 13、unfavourable temperature：不适宜温度 14、tropical trpkladj. 热带的 15、zone zonn. 地带 16、temperate temp()rt adj. 温和的；适度的 tropi

6、cal zone：热带 temperate zone：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 adverse soils. It is characterized by high cropping

7、 intensity and intensive use of agrochemicals,Words to remember,17、duration durenn.生育期，持续的时间 18、nitrogen fertilizer：氮肥 19、biological stress：生物逆境 20、cropping intensity：种植密度 21、agrochemical ,rokmkln. 农用化学品,Production constraints in low (1ess than 3t ha-1) and medium yield (3-5t ha-1) areas are delayed

8、 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 problem; associated poor drain-age and environmental stress

9、es.,Words to remember,22、constraint knstrent n.约束；限制 23、salinity：slntin. 盐度；盐分；盐性 24、alkalinity ,lklntin. 碱度；碱性 25、drainage drendn. 排水；排水系统,Problems associated with high production (more than 5t ha-1) areas are yield instability due to pests, multiple cropping systems-delaying transplanting and envi

10、ronmental degradation.,Words to remember,26、instability ,nstbltin. 不稳定，基础薄弱 27、multiple cropping systems： 多熟制种植 28、transplanting：移栽 mechanical transplanting 机械化移栽,Rain fed lowland rice grows in budded fields that are flooded for at least part of the cropping season to water depths that do not exceed

11、 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, contributing 18% of the total production.,Rainfed lowland rice ecosystems,Words to r

12、emember,29、Rain fed lowland rice 雨养湿地水稻 30、consecutive knsekjtv adj. 连贯的；连续不断的,Rainfall is often erratic, so that conditions are diverse and unpredictable. Typically，traditional photoperiod-sensitive cultivars, which do not respond to fertilizer，are grown. No water harvesting/conservation facilities

13、 are available on the farm and there is no irrigation water availableFive major environments have been identified within the rainfed lowland ecosystem. These are,Words to remember,31、erratic rtkadj. 不稳定的 32、photoperiod ftprd n.光周期 photoperiod-sensitive cultivars 光周期敏感的品种 33、water harvesting：雨水收集,i.

14、Rainfed shallow favourable environments：No drought or waterlogging ii. Rainfed shallow drought prone environments：These areas have frequent and severe water-deficit problems and are drought proneThe rainy season may be short (90-100 days) as in central and eastern India or long with erratic distribu

15、tion as in Bangladesh and Thailand,iii. Rainfed shallow drought and submergence prone environment: Areas subjected to both drought and waterlogging. iv. Rainfed shallow submergence prone environments: Frequent short-term flooding that may damage or destroy the crop. v. Rainfed medium deep rice envir

16、onment: 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 35、prone pronadj.有倾向的，易于的 36、submergencesbmdns n. 下潜，淹没,Of the 148 m. ha total rice area, this ecosystem covers about 18 million hectares of which 64 per cent is located i

17、n 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. Yields are typically 1 t ha-1. In Asia, most upland rice is grown on rolling and mountainous lan

18、d with slopes varying from 0% to more than 30%.,Upland rice ecosystems,Words to remember,37、rotation r()te()n n.轮作，循环，轮流 38、rolling rl n. 旋转；动摇 adj. 旋转的；起伏的；波动的 39、slope slp n. 斜坡；倾斜；斜率；,Dry soil preparation and direct seeding in fields that are generally unbunded are characteristic of the upland ri

19、ce 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 save scarce water. Shifting cultivation in common in Indonesia, Laos , the PhiliPpines, northern Thailand and Vie

20、tnam. 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 41、bunded -unbunded 42、surface water： 地表水 43、shifting cultivation：轮作耕种,Soils are low in fertility and weeds are a major constra

21、int; 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. Favourable uplands with long growing season, ii. Favourable environment with short growing season, iii.

22、Unfavourable environment with long growing season and iv. Unfavourable environment with short growing season. Major constraints are drought, weeds, low rates of inputs, poor input management, poor soil fertility and environmental stresses.,Words to remember,44、fertility ftlt n. 多产；肥沃，肥力 soil fertili

23、ty:土壤肥力 45、hilly hili adj. 丘陵的；多小山的；多坡的 46、mono adj 单的 mono croping： 单一作物制 47、detrimental ,detrment()l adj. 不利的；有害的 48、growing season：生长季，生长期,Since water is the major constraint in upland rice ecosystem, a major part of area under rainfed upland ecosystem is direct seeded, generally at the onset of

24、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 evapotranspiration） is quite high. This is called as Moist I period (rainfall is less than PET but more than 1/2 PET). After this perio

25、d, 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 50、canopy knpi n. 天篷；华盖； 51、potential evapotranspiration：潜在蒸散量。 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n. 潮湿 53、humid hjumd adj

26、. 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). During 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

27、 swamps of the flood plains and deltas and on the slopes of natural levees in South AsiaThese are the regions where 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

28、and tidal wet land rice ecosystems,Words to remember,54、tidal wetland rice 滩涂湿地水稻 55、swamp swmpn. 沼泽；湿地 56、flood plain：冲击平原 57、deltas delt n.（河流的）三角洲 58、levee lev n. 堤坝（码头）；,These areas are found in the river basins（盆地） of Ganges(ndi:z n. 恒河) and Brahmaputra (,br:mpju:tr, n. 雅鲁藏布江) in India and Bangladesh (,ba:glde, n. 孟加拉国), the Irrawaddy (,irwdi, n. 伊洛瓦底江) in Myanmar (mjnm:, n. 缅甸, the Mekong（meik, n. 湄公河） Delta of Vietnam (,vjetnm, 越南) and Cambodia (kmbudi,柬埔寨) and the Chao Pharaya（tauprai 湄南河） in Thailand (tailnd泰国).,When