3.1 Climate

The air temperature of the Three Gorges reservoir area was higher than the historical average with obvious less precipitation in 2006 (December of 2005-November of 2006) due to global climate warming and abnormal atmospheric circulation. The temperature spatial distribution characteristics of the reservoir area showed higher than historical average data in each typical weather station. Air temperature of winter was similar to that of normal years but higher in spring, summer and autumn. In annual precipitation of the reservoir area, the average annual precipitation of each typical weather station was less than the historical average. In the four seasons, winter had more the precipitation was more in winter, similar in spring and autumn but less in summer compared with the historical average. There was no large-scale serious storms and flood disaster all year round. The average wind speed of the reservoir area was similar to normal level with evident less foggy days. The evaporation was obviously higher than normal level with smaller relative humidity. The acid rain was less frequent compared with in 2005. Summer was subject to high temperature and serious drought. The occurrence of storms and flood disasters and their secondary geological disasters in summer was less than normal level. However, some of the reservoir areas suffered from relatively serious snow and freezing disasters in winter and spring.

Table 3-1 Monitoring results of meteorological items of each typical weather

station of the Three Gorges reservoirarea in 2006

In 2006, average precipitation of the reservoir area was 877.6 mm, 244.6 mm less than the normal level, being a year lack of precipitation. Annual precipitation of each typical weather station ranged from 763.5 mm to 1083.8 mm, 20%-30% less than the normal level. Maximum precipitation occurred in Zigui and minimum in Fengjie. In temporal distribution, precipitation of the reservoir area in each season was not even. The precipitation was higher in 2005/2006 winter, similar to the normal level in spring and autumn but less in summer. The precipitation of the reservoir area in December, June, July, August and October was 30%-70% less than the historical average in the same month, but more than twice in February. The precipitation of the remaining months was similar to the normal level.

Figure 3-1 Percentage of precipitation anomaly of the Three Gorges reservoir area in 2006

In 2006, the average temperature of the Three Gorges reservoir area was 18.8℃, 1.0℃ higher than the historical level and the warmest year since 1961. This was consistent with the background of abnormal higher national average temperature in 2006. In spatial distribution, the annual average temperature of each typical weather station was higher than the normal level. Among these stations, average air temperature of Changshou, Fuling, Fengdu, Wanzhou, Fengjie, Wushan, Badong and Yichang was 1.0-1.6℃ higher than the historical average. In temporal distribution, the air temperature of the reservoir area was similar to normal level in winter, but higher in spring, summer and autumn, especially in summer and autumn. The monthly average temperature was higher than the historical average in all months except December and February (lower), this was especially true in July, August and October with 2.2-2.4℃ higher than the historical average.

Figure 3-2 Temperature anomaly of the Three Gorges reservoir area during 1961-2006

The wind of the reservoir area was not strong in 2006 with average wind speed of 1.2 m/s, similar to the normal level. The annual average wind speed of all weather stations was 1.0-2.0 m/s except the Fuling Station, Wanzhou Station and Wushan Station (about 0.7 m/s). The maximum wind speed occurred in Badong at 2.0 m/s and minimum at 0.6 m/s in Wushan.

There were 24 foggy days on the average in the reservoir area in 2006, 14.2 days less than the normal level, the least since 1976. It was the 5 consecutive year with less　than　average foggy days since 2002. In seasonal distribution, there were 9.1 foggy days in winter, 7.0 days in spring, 5.8 days in autumn and 2.2 in summer. The amount of foggy days in winter, summer and autumn was 4-6 days less than the historical average but similar in spring. In spatial distribution, there were more foggy days in western part of the reservoir area than that of eastern part. The amount of annual foggy days was 45-55 days in Changshou, Fuling and Zhongxian; 35 days in Badong, 29 days in Fengdu and 25 days in Chongqing, but less than 20 days in other places. Among them, there were only 2-3 foggy days in Fengjie, Wushan and Zigui. There were 10.2 more foggy days in Yunyang and 2.7 more foggy days in Zigui than the historical average. In other stations, there were 2-33 foggy days less than the historical average. Among them, Wanzhou had 32.6 days less than the historical average.

In 2006, the average relative humidity of the reservoir area was 71%, 7% less than the normal level. It gradually decreased from western part to the middle part of the project area then had some rise into the eastern part. Compared with the historical level, the average relative humidity of each typical weather station was less than or similar to the normal level except Zigui station had 3% increase. There was relatively big seasonal variation of average relative humidity with only 65% in the summer, the lowest in four seasons due to rare drought. The average relative humidity was 70% in spring, 75% in winter and 73% in autumn.

In 2006, the average evaporation of the Three Gorges reservoir area was 1428.5 mm, nearly 200 mm more than the historical average. The average evaporation of each weather station recoded 10%-20% more evaporation than the normal level with evident rise in western part of the area. The highest annual average evaporation occurred in Badong (1698.7 mm), Wushan (1634.4 mm) and Fengdu (1606.4 mm) with 1200.0-1500.0 mm in other stations. Only Yunyang and Yichang recorded lower-than-normal average evaporation in the winter. The average evaporation of most stations in the spring, summer and autumn was higher than or similar to the historical average with most evident increase in the summer.

In 2006, the average pH value of the precipitation of 6 weather stations in the reservoir area was 4.55, similar to that of 2005 and falling into the normal acid rain range. The average pH value of the precipitation of the Three Gorges reservoir area had been the second lowest precipitation pH since 1999 with the lowest in Chongqing, Badong and Yichnag and second lowest in Fengjie. On the whole, the acid rain degree over the past two years was heavier than before.

In 2006, the most striking climate disasters in the reservoir area was heat wave and drought in the summer, followed by local storms and floods and resulting secondary geological disasters such as landslide and mud-stone flow as well as strong local convective weather like gales and hails. In winter and spring, prominent disaster included low temperature, freezing damages, snow disasters and dense fogs.

High Temperature and Drought: Rare long-term less rain and high-temperature weather occurred in the reservoir area in the summer leading to rapid development of drought. Among them, Chongqing Municipality suffered from a most serious drought (1 one 100 years) with heavy loss.

The average precipitation of the reservoir area was only 247.0 mm during June-August, less than half of the historical average, the least of the same period since 1951. The average temperature was 29.0℃, 2.0℃ higher than the normal level. Most places of the Three Gorges reservoir area had 40-60 days with ≥35℃ high temperature, 20-30 days more than the historical average. From mid July to late August, the extreme temperature of most areas of Chongqing Municipality was 38-40℃, the more extreme temperature of over half of the Municipality exceeded 40℃. 70% of the weather stations of the Municipality had the record high daily maximum temperature. The maximum temperature of Qijiang was as high as 44.5℃ on August 15 and September 1, the highest record of Chongqing in the history.

21 million people of Chongqing suffered from the high temperature summer drought. 8.204 million people and 7.488 million livestock had temporary difficulties in getting access to drinking water. 1.327 million ha crops suffered in the drought with no yield in 375,000 ha farmland, about 30% grain reduction, 382,000 ha of withering and dieing forest and 9.07 billion yuan direct economic loss.

Storms and Floods: In 2006, the storm and flood disasters and resulting geological disasters like landslide and mud-stone flow were slighter than normal level.

A strong precipitation occurred from the western to eastern part of the reservoir area during May 8-13 with 50-100 mm precipitation. As a result, a total of 2.013 million people of areas including 15 districts, counties and cities of Chongqing Municipality, Yuan'an and Badong of Hubei Province were affected with 2 deaths, 72,000 ha cropland suffered, 12,000 building damaged and direct economic loss of 110 million yuan. Most areas of Chongqing Municipality had a strong rain in the night of May 23 due to the impacts of high trough and ground cold air, leading to mountain torrents in some areas and resulting geological disasters such as landslide and mud-stone flow. 1.221 million people and 48000 ha cropland of 9 districts, counties and cities were hit by the disaster with the damage & destruction of 17,000 buildings and 120 million yuan direct economic loss. Several strong precipitations of the area during June and July hit a population of 3.234 million, leading to emergency move of 157,000 people, yield reduction of 89,000 ha cropland and no yield of 14,000 ha cropland, collapse of 15,000 buildings, damage of 49,000 buildings and 670 million yuan direct economic loss.

Gales and Hails: In 2006, there were evidently less gales and hails compared with that in 2005, so was economic loss. According to statistics, over 60 county?times of strong convective weather process including gales and hails attached the reservoir area all year round, leading to about 720,000 people and 86,000 ha cropland affected, more than 106,000 buildings damaged or destructed with direct economic loss of 260 million yuan.

Freezing damages and Snow Disasters: Some local places of the Three Gorges reservoir area were hit by relatively severe snow disasters and freezing damages in winter and spring. The area of Enshi Autonomous Prefecture of Hubei Province with altitude more than 400 m above sea level had big snow during Feb. 16-17, causing 35 cm snow depth in Guandian Town of Jianshi County and 580,000 people from 68 towns of 8 counties (cities) affected with direct economic loss of about 87 million yuan. During February 27-28, intermediate and big snow occurred in Yidu City of Hubei Province with over 10 cm snow in most areas and some places even 17 cm. As a result, 117,000 people were affected with the collapse of some houses and freezing damage to rape and tea trees, failure of power lines and telecommunication facilities and near 10 million yuan direct economic loss. Large scale cold wave occurred during March 10-14 in Chongqing Municipality with temperature drop of over 10℃ and even 16℃ in some area. A total of 19 districts and counties were subject to freezing damages at different degrees leading to a population of 2.614 million affected and direct economic loss of more than 80 million yuan.

Dense Fog: In 2006, there were less dense foggy days in the Three Gorges reservoir area. However, traffic jam and accidents resulting from local dense fog sometimes occurred.

3.2 Terrestrial Plants

The Three Gorges reservoir area had rich terrestrial plant species. There were 6,088 vascular plant species in the area, 56 of them were rare and endangered species enjoying good protection. About 2.7 million ha land of all counties in the area were for forestry and natural forest occupied about 2.10 million ha land.

Analysis on the biodiversity of various forest communities of the reservoir  area found that the biodiversity index trend of coniferous forest was shrub layer﹥herb layer﹥tree layer. The general trend of evergreen broad-leaved forest biodiversity index was shrub layer﹥tree layer﹥herb layer. The overall trend of the biodiversity index of deciduous broad-leaved forest had no obvious pattern. However, biodiversity index trend of oak forest was bigger index in shrub and herbal communities than that of tree layer. But the rank of shrub biodiversity index and that of herbal communities was not constant. The biodiversity index trend of coniferous and broad-leaved mixed forest was shrub layer﹥tree layer﹥herb layer. There was no obvious pattern for the biodiversity index trend of evergreen and deciduous broad-leaved forests.

3.3 Terrestrial  Animals

There were 575 species of 298 genera of 100 families of 29 orders of 4 classes of terrestrial vertebrates in the Three Gorges reservoir area. 58 species of them only live in China, and 38 were unique species mainly distributing in China making the total endemic species 96. There are 76 species animals under national protection program, including 10 species of the first-class national protected animals (Moschus berezovskii was upgraded from the second-class to the first-class national protected animal) and 66 species of the second-class national protected animals.

Water Birds: In 2006 winter, there was no obvious change of the amount of mandarin ducks in the Daning River of the reservoir area after impoundment. 39 mandarin ducks (30-40 were observed in the winter water birds monitoring program from early 2001 to the beginning of 2003), 10 mallards, and over 40 grebes were recorded at the Daning River mouth - Dachang Town section subject to the influence of impoundment. Before and after 139 m impoundment, the total amount of migrant water birds dominated by wild goose and duck had no big difference. But there was evident change of the amount and distribution of other water birds. For example, total amount of 11 species of water-front-habitat birds had obvious decline.

Raptors: 7 nests of Chinese Goshawk and 4 Accipiter virgatus nests were found in Xingshan County and Badong County, both of them are small raptors and falling into the second-class national protected animals. In addition, distant shooting recorded a Chinese goshawk labeled by China Bird Label Center in the Bohai Gulf in autumn four years ago, indicating that Chinese goshawk, which reproduces in Northeast Asia, could migrate and reproduce in South China. Propagation behavior ecological study shows that Chinese goshawk has special reproduction behavior in case of emergency. For example, when the male parent is missing and the female parent of a nest of babies dies from snake attach, another male Chinese goshawk comes to feed the baby birds. The discovery of this "altruism" has great academic significance in the study of raptors.

Primates: Continuous monitoring in the protected area of golden monkey along the Yanduhe River in Badong County found that the sub-species of golden monkeys--the first-class national protected animal--use their habitat in clockwise ring moving method in Shennongjia area, totally different from expert's view that golden monkeys in Sichuan Province have fixed habitat.

3.4 Fishery Resources and Environment

3.4.1 Fishery Resource

In 2006, the total catch of natural fishes in such waters as the Three Gorges reservoir, waters downstream the Dam, Dongting Lake, Poyang Lake and river mouth area was 55,000 tons, down by 14.1% compared with that of 2005. The fish fry flow of the "Four major local fish species" at Jianli section downstream the Dam had some rise compared with that of 2005. But the parent crab and Coilia mystus in estuary area had decline at different degree. The amount of eel fry had some rise.

l Reservoir Area

In 2006, the total catch of natural fishes in reservoir area was 2111 tons, up by 16.0% than in 2005. If we estimate the catch of individual species in the light of species composition, 390 tons were bronze gudgeon, 380 tons were silver carp, 330 tons were carp, 170 tons were Rhinogobio ventralis，170 tons catfish, 90 tons large-mouth bronze gudgeon and 90 tons grass carp.

Among the catch, the bronze gudgeon, silver carp, carp, Rhinogobio ventralis, catfish, large-mouth bronze gudgeon and grass carp dominated 76.7% of the total and were major commercial fish species. However, the size of large-mouth bronze gudgeon and catfish was still relatively small and their age rather young.

l Waters downstream the Dam

In 2006, the total catch of natural fishes in waters downstream the Dam was 1,750 tons, down by 11.2% than that of 2005. If we estimate the catch of individual species in the light of species composition, 540 tons were carp, 470 tons were bronze gudgeon, 70 tons were catfish and 140 tons Pelteobagrus fulvidraco.

Bronze gudgeon, catfish, carp and Pelteobagrus fulvidraco took up 69.7% of the total catch and were major commercial fish species in the waters.

l  Spawning sites of the "Four Major Local Fish Species"

In May-June of 2006, the amount of fish fry flow of the "four major local fish species" at the Sanzhou monitoring section in Jianli County downstream the Three Gorges Dam was 231 million with some rise compared with that of 2005 but still at low level, only 9.2% of the average level before the impoundment (1997-2002). The fish fry mainly occurred during late June and early July.

There was a change in the species mix of the fish fry of the"four major local fish species" before and after the impoundment. Before the impoundment, grass carp dominated the fish fry accounting for 60-85%. After the impoundment, the percentage of silver carp went up to 59.9% in 2006 and in dominance.

l Dongting Lake

In 2006, the catch of natural fishes in Dongting Lake was 22,000 tons, down by 6.8% than that of 2005. Among them, the catch of 10,900 tons came from the east Dongting Lake, 6,100 tons from the south Dongting Lake and 5,000 tons from the west Dongting Lake, accounting for 49.5%, 27.7% and 22.7% of the total annual catch respectively.

The catch was dominated by resident fishes like carp, crucian carp, catfish, Pelteobagrus fulvidraco, and the "four major local fish species", taking up 45.3% and 5.4% respectively in the total sampled catch.

l Poyang Lake

In 2006, the catch of natural fishes in Poyang Lake was 28,600 tons, down by 20.6% compared with that of 2005. Carp, crucian carp, catfish, Pelteobagrus fulvidraco, mandarin fish, bream and the "four major local fish species" dominated the catch with 11,740 tons of carp, 4,010 tons of crucian, 3,238 tons of catfish, 2,887 tons of Pelteobagrus fulvidraco and 907 tons of the "four major local fish species".

1-2 year old fish dominated the catch and took up 72.4% of the total. The percentage was 21.9% for 3-year-old fish, 5% for 4-year-old fish and only 0.7% for 5-year-old fish.

l Estuary Area

As the last section of the Yangtze River to the sea, estuary waters are the meeting place of marine and fresh water, which not only provide migration passage for many aquatic animals, but also serve as ideal habitat and reproduction site for brackish water creatures. There are rich fishery resources of important commercial fish species such as Coilia mystus, eel fry and Eriocheir sinensis.

In 2006, the catch period was shorter than that of the last year for parent crab and eel fry but longer for Coilia mystus in the estuary. The average operation days of the three types of monitoring ship during the whole catch period were less than that of 2005. The issuing amount of catch license went down by 20.6% for Coilia mystus but rose by 66.9% for eel fry compared with that of 2005.

In the wet season of 2006, Coilia mystus parent population was mainly in the southern braches of the Yangtze River and catch peak period from mid May to mid June. The average one-ship catch of Coilia mystus during the catch period and total catch of the estuary was 3,022 kg and 408.0 tons respectively, down by 36.9% and 49.9% respectively compared with that of the same period of 2005. The average fish length and tail weight was 143mm and 14.6 g respectively, down by 7.1% and 15.2% respectively compared with that of the same period of 2005.

The salinity of the waters where parent crabs (of Eriocheir sinensis) reproduce was 2-3‰ in tide ebbing and 4-6‰ during tide rise. The average one-ship catch of parent crabs during the catch period and total catch of the estuary was 84.5 kg and 1532.0 kg respectively, down by 67.8% and 87.3% respectively compared with that of the same period of 2005. The average shell length, width and body  weight was 63 mm, 69 mm and 158 g respectively, up by 1.6%, 1.5% and 9.0% respectively than that of the same period last year.

The average one-ship catch of eel fry during the catch period and total catch of the estuary was 20,415 and 59.204 million (8466.2 kg equivalent) respectively, up by 30.7% and 113.6% respectively compared with that of the same period of 2005.

3.4.2 Fishery Water Environment

In 2006, 7 monitoring stations and sites (Yibin, Banan, Wanzhou, Jingzhou, Yueyang, Hukou and Estuary) were set up in the mainstream of the Yangtze River, Dongting Lake, Poyang Lake and estuary area to monitor water quality of main fishery waters of the Yangtze River basin. The assessment of water quality was in line with the Water Quality Standard for Fisheries (GB11607-89). For the items not covered by the Standard, assessment was carried out according to the relevant function class specified in the Environmental Quality Standards for Surface Water (GB3838-2002). Monitoring results showed that the overall quality of important fishery waters of the Yangtze River basin was good in 2006 and basically met the requirements for fish growth and reproduction. Some waters were subject to certain pollution with major pollutants being copper, total nitrogen (TN) and total phosphorus (TP).

Major pollutant of fishery waters in Yibin and Banan of the upstream of the Yangtze River was copper with its concentration going beyond fishery water quality standard during the reproduction, growth and overwintering period. Other monitoring items did not go beyond the standard. All monitoring items in Wanzhou fishery waters did not go beyond the standard.

The fishery waters of Jingzhou and Chenglingji of the midstream of the Yangtze River were subject to certain pollution with major pollutants of TP, TN and ammonia nitrogen. TP concentration of 66.7% of water samples of Jingzhou waters went beyond the standard during the reproduction period. TN concentration of Chenglingji waters exceeded the standard during the overwintering and growth period. And ammonia nitrogen level exceeded the standard during the fish reproduction and growth period.

The overall water quality of the egg-laying site of Chinese sturgeon  in Yichang of Hubei Province and egg-laying sites of the "four major local fish species" at Sanzhou of Jianli County during the reproduction period was good with all monitoring items meeting the standard.

Major pollutants of the Dongting Lake fishery waters were TN, TP and non-ionic ammonia. Go-beyond standard rate of TN was 44.4% during the fish growth period and 33.3% during the reproduction period. Go-beyond standard rate of TP was 55.6% in overwintering period, 11.1% during the reproduction period and 11.1% during the growth period. Go-beyond standard rate of non-ionic ammonia was 77.8% in the fish growth period.

Major pollutants of the Poyang Lake fishery waters were TP with go-beyond standard rate of 100% during the fish overwintering period, 100% during the reproduction period and 33.3% during the growth period.

Major pollutants of the estuary fishery waters were TN and TP. During the catch period of eel fry, Coilia mystus and parent crabs. TN go-beyond standard rate was 100% for all catch species. TP go-beyond standard rate was 33.3% for eel fry, 16.7% for Coilia mystus and 66.7% for crabs.

3.5 Endemic Fish Species and Rare Aquatic Animals

3.5.1 Endemic Fish Species in the Upper Reaches of the Yangtze River

In the spring and autumn of 2006, two field investigations were carried out in such river sections of the upper reaches of the Yangtze River as Panzhihua, Yibin, Hejiang, Mudong, Fuling, Wanzhou and Yichang with catch of 127 fish species. 28 of them were endemic fishes in the upper reaches of the Yangtze River. 6 of them were invasive alien species including Acipenser schrencki, Tincaeus, Letalurus Punetaus, Letalurus melas, Microptorus salmonoides and Tilapia mossambica. Acipenser schrencki was discovered for the first time in Panzhihua section of the river. Apart from some change of the catch mix in Wanzhou section of the river, there was no obvious change of the catch fish mix in other sections of the Yangtze River compared with that of 2005.

If we estimate the catch of individual species in light of species composition, endemic fish species of each river section had a certain percentage with 30.8% at Fuling section, 23.8% at Hejiang section, 22.6% at Panzhihua section, 20.9% at Yibin section, 18.7% at Mudong, 14.9% at Wanzhou and 11.1% at Yichang river section. Judging from the length, weight and age structure of the catch, endemic fish species as major fishery targets of each section of the Yangtze River showed the trend of smaller size and younger age. This indicated that the fishery intensity of the mid and upstream of the Yangtze River was relatively big with excessive development of fish resources and poor replenishment. Judging from the weight and amount, endemic fish species of the catch at Panzhihua, Yibin, Hejiang, Mudong and Fuling sections took up a significant proportion. However, the weight and amount percentages of the endemic fish species at Wanzhou section and Yichang section were relatively low, an evident decline compared with that of 2005.

Early fish resource monitoring activities at Panzhihua section collected the eggs of such fish species as large mouth bronze gudgeon, Leptobotia elongata, Jinshaia sinensis and Lepturichthys fimbriata. The spawning sites distributed 1.5 km-48.4 km river section upstream Jinshatan with peak period in May and June. Investigation results showed that there was still the reproduction of the "Four major local fish species" at Yichang section in the midstream of the Yangtze River with 2 egg-laying sites, one at the section from Yiling Yangtze River Bridge to Huyatan and the other at the section from Yunchi to Yidu.

3.5.2 Rare and Precious Fish Species

Based on the distribution of caught egg-hunting fish during the natural reproduction period of Chinese sturgeon, no Chinese sturgeon egg was found at the spawning site at the section from downstream of Gezhou Dam to Miaozui and the sections from Mojishan to Wulong and Huyatan in 2006. Before and after the egg-laying period, Chinese sturgeon was seen at the section from Gezhou Dam to Yanshou Dam with about 316 parent fish. There was only once egg-laying period occurring during November 13-14 early morning in 2006 with about 1.965 million eggs. It was estimated that 3.05 female Chinese sturgeons had produced eggs.

In 2006, there was no accidental catch of Chinese paddlefish and Chinese sturgeon at midstream and upstream of the Yangtze River. One accidental catch of Acipenser schrencki occurred at Yibin section of the Jinsha River. Accidental catch of 20 tails of young Myxiocyprinus asiaticus occurred at Wanzhou section in Chongqing. 8 Myxiocyprinus asiaticus were accidentally caught at Yichang section, 5 of them were male and 3 female with body weight ranging from 5.0 kg to 9.5 kg.

3.6 Agricultural Ecology

Surveys on agricultural production of 150 towns of 19 districts or counties of the Three Gorges reservoir area were carried out in 2006, similar to that of 2005 (Total amount of towns decreased by 31 due to resettlement and merge of towns).

3.6.1 Ecological Environment of the Farmland

In 2006, there was some reduction of ecological environment pressure on the farmland of the Three Gorges reservoir area but the situation was still grave. Arable land area and total sown area continued going down. But the area of forests, orchard and commercial crops went up. Agricultural production was still dominated by grain crops.

In 2006, total arable land area of the Three Gorges reservoir area was 189,128 ha, down by 1.5% compared with that of 2005. There was certain increase of per capita arable land due to population decline, reaching 0.046 ha. The area was 89,027 ha for paddy field and 100,101 ha for dry land, accounting for 47.1% and 52.9% respectively with paddy field proportion up by nearly 5 percentage points compared with that of 2005. 57.2% paddy field adopted two-crop system, down by 1.9 percentage points compared with that of 2005. 62.2% of dry land adopted three-crop system, similar to that of the last year.

In 2006, more efforts were made to transform slope land to terraced fields and return reclaimed arable land to forest or grassland in the reservoir area. As a result, 18,013 ha cropland realized "grain for green" and 6,067 ha slope land were transformed into terraced fields. The arable land distribution was better. Arable land with slope less than 10o and between 10°-15°took up 22.1% and 31.3% of the total, up by 1.23 and 0.69 percentage point respectively compared with that of 2005. While the arable land with the slope of 15°-25°and larger than 25°accounted for 30.1% and 16.5% of the total area, down by 1.77 and 0.15 percentage point respectively compared with that of 2005.

In 2006, the multiple crop index of the area was 241.1%. The total crop sown area reached 456,022 ha, down by 9.2% than in 2005. Among them, the sown area was 332,460 ha for grain crops and 123,562 ha for commercial crops, accounting for 72.9% and 27.1% of the total respectively. Compared with in the last year, the proportion of commercial crop area went up by 1.9 percentage points.

3.6.2 Rural Energy

In 2006, the rural energy mix of the reservoir area continued its improvement but still dominated by direct burning of firewood and stalks with accelerated development of biogas. In the energy mix, firewood and stalks took up 68.9%, small coal pit 20.5%, small hydro station 2.3% and biogas 8.3%. Compared with that of 2005, the energy proportion was 2.9 percentage points down for firewood and stalks, 0.1 percentage point up for small coal pit, 0.1 percentage point up for small hydro stations and 2.7 percentage points up for biogas.

In 2006, rural biogas enjoyed rapid development in the Three Gorges reservoir area. Among the 1.3730 million rural households, there were a total of 84,250 biogas pits with annual capacity of 55.069 million m3, 8.33 biogas pits per 100 households.

3.6.3 Crop Plant Diseases and Insect Pests

In 2006, no new crop plant disease and insect pest was found in the reservoir area. There was no outbreak of certain plant diseases and insect pests and major damage. The area subject to plant diseases and insect pests had dramatic decline with evident prevention and control effects, less damage and economic loss.

The total farmland area suffering from plant diseases and insect pests in the area was 385,955 ha*times, down by 19.6% compared with that of 2005. Among them, 250,012 ha*times were for insect pests and 135,943 ha*times were for plant disease, down by 19.0% and 20.5% respectively than in the last year.

There was a big increase of plant disease & insect pest prevention and control rate in the area with total 390, 879 ha*times under prevention and control and the rate being 101.3%, up by 7.1 percentage points than in 2005. Among them, 261,949 ha*times were for the prevention and control of insect pests and 128,929 ha*times were for the prevention and control of plant diseases with the rate of 104.8% and 94.8% respectively, up by 10.4 and 0.9 percentage point respectively compared with that of 2005. Actual grain loss was 35,895 tons and 112,423 tons of potential grain loss was averted.