Search Result of "Fang Tiangi"

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Relationship Between Sluicing for Irrigation and Spreading of Oncomelania hupensis in Hubei Province)

ผู้เขียน:ImgXu Xingjian, ImgFang Tiangi, ImgYu Zhuanhua, ImgJiang Yong, ImgCao Jiuhua

สื่อสิ่งพิมพ์:pdf

Abstract

The snails Oncomelania hupensis, can drift into a ditch inside the sluice when it was opened for irrigation. Of 381 sluices on the dike of 14 main rivers in Hubei province, 226 (59.3%) of the sluices were snail – ridden inside and/or outside. Fifty of 226 sluices (22.1%) in the dich inside the sluice were confirmed being snail – ridden due to irrigation. The areas of snail spreading were 23,084.9 mu (1 mu = 0.00667 ha), or 68.57% of the snail habitats in areas covered by irrigation. The opening of sluices for irrigation would cause the snails to drift into the ditch inside the sluice. Such phenomenon did not correspond with the time when smail was found in the ditch inside the sluice. Also there was no singnificant difference during the investigation period from 1980 to 1987 and the size of snail habitats outside the sluice. There was no direct proportion to the number of outlets and the flow of sluice, the number of annual average days of opening sluices, and the frequency of opening sluices. Of 26 sluices with increasing number of snails, the increase in length and area of snail – ridden in the ditch inside the sluice was 2.26 times and 5.02 times respectively in 1987 to those in 1980. It showed that the speed of snail eradication could not keep pace with the speed of snail spreading.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 023, Issue 3, Jul 89 - Sep 89, Page 281 - 286 |  PDF |  Page 

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Observation on Collecting Oncomelania hupensis When Opening The Sluices During Flood Season in Yangtze River)

ผู้เขียน:ImgXu Xingjian, ImgFang Tiangi

สื่อสิ่งพิมพ์:pdf

Abstract

To ascertain whether Oncomelania hupensis can spread into the ditch when a floodgate was open, an observation was made in the snail-ridden area during the flood season of Yangtze River in Jia Yu County from July to September 1987. The snails were collected at the ditch inside the floodgate for 71 hours and 25 minutes within 9 days. The flow through the net was 179-982 m, 145 snails were gained with blocking net at the flow speed of 0.02-1 meter/second, its average density was 0.81 snails/1000m (0.21-6.73 snails/1000m). The number of gained snail at the lower section of the ditch were 6.25 times as high as that caught at the upper section. The number of snails in water was decreasing with the depth of the water. The area of 846m was scooped inside the floodgate for 5 days, its average density was 1.52 snails/m. The area of 220 m was scooped around the opening outside the floodgate for 4 days, its average density was 0.63 snails/m of all the gained snails, 98.79% were young with a whorl under 6.5 The result showed that when the floodgate was sluiced for irrigation, snails could spread into the ditch and thus snail-ridden areas increased accordingly.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 022, Issue 3, Jul 88 - Sep 88, Page 251 - 260 |  PDF |  Page