Water and Soil Conservation in Taiwan Based on Theoretical Research of Water and Soil Ecology

Taiwan has always attached great importance to management of mountain slopes, and its steepslope water and soil conservation system has been a reference for the water and soil conservation in hot and rainy regions. From the perspective of water and soil ecology theory, new forms of water and soil loss emerged since the industrialization and urbanization of Taiwan, also known as hidden water and soil loss, such as soil hardening, change of original landform, destruction of ecological landscape etc.. These losses should be controlled through water and soil conservation measures such as initial involvement, dynamic analysis, systematic treatment and disaster avoidance, all production and construction activities should follow three elements(water, soil and vegetation) and their correlation laws, in order to maintain water and soil ecological balance. By integrating water and soil ecological concepts, water and soil conservation in Taiwan will make more progress.

Impacts of water and soil erosion in upstream watershed of Nenjiang River

Making a brief analysis of the water and soil loss present situation in Daxing＇anling area which locates to the upstream region of Nenjiang River, and giving the water and soil loss of this area that have been made near 20 years, as well as the factors of the water and soil loss. According to the factors corresponding prevention measure and forecast model have been put forward, make a brief introduction to this model in this article. It is helpful to improve the local soil conservation and sustainable development.

A new ecological control method for Pisha sandstone based on hydrophilic polyurethane

The Pisha sandstone-coverd area is among the regions that suffer from the most severe water loss and soil erosion in China and is the main source of coarse sand for the Yellow River. This study demonstrated a new erosion control method using W-OH solution, a type of hydrophilic polyurethane, to prevent the Pisha sandstone from water erosion. We evaluated the comprehensive effects of W-OH on water erosion resistance and vegetation-growth promotion through simulated scouring tests and field demonstrations on the Ordos Plateau of China. The results of simulated scouring tests show that the water erosion resistance of W-OH treated area was excellent and the cumulative sediment yield reduction reached more than 99%. In the field demonstrations, the vegetation coverage reached approximately 95% in the consolidation-green area, and there was almost no shallow trenches on the entire slope in the treated area. In comparison, the control area experienced severe erosion with deep erosion gullies appeared on the slope and the vegetation coverage was less than 30%. This study illustrated that W-OH treatment can protect the Pisha sandstone from erosion and provide the vegetation seeds a chance to grow. Once the vegetation matured, the effects of consolidation-growth mutual promotion can efficiently and effectively improve the water erosion resistance and ecological restoration.

Understanding the attitudes and practices of paddy farmers for enhancing soil and water conservation in Northern Iran

The objective of this paper was to identify the factors affecting rice growers’attitudes and practices towards water and soil conservation in the Fumanat Plain of Guilan Province,Iran.Data were collected through a survey questionnaire addressing a cross section of 400 rice growers of the Fumanat Plain in four districts.Data were analyzed using both summary statistics and multivariate statistical procedures while content validity of the statements was first determined by a group of experts of water and soil conservation.It was found that more than 23% of the variance of attitudes towards water and soil conservation could be determined by a linear combination of variables included in a regression equation.Identifying the factors affecting rice growers’attitudes is suggested as a way of integrating rice cultivation into rural development.From a practical point of view,the above mentioned implications are of great importance generally for society,policy makers and related economic sectors.

Impacts of water conservancy and soil conservation measures on annual runoff in the Chaohe River Basin during 1961-2005

Taking the Chaohe River Basin above the Miyun Reservoir in North China as a study area, the characteristics and variation trends of annual runoff and annual precipitation during 1961-2005 were analyzed applying Mann-Kendall test method on the basis of the hydrologic data of the major hydrological station （Xiahui Station） located at the outlet of the drainage basin and the meteorological data of 17 rainfall stations. Human activities including water conservancy projects construction and water diversion as well as implementation of soil and water conservation from 1961 to 2005 were carefully studied using time series contrasting method. The referenced period （1961-1980） that influenced slightly by human activities and the compared period （1981-2005） that influenced significantly by water conservancy and soil conservation measures were identified according to the runoff variation process analysis and abrupt change points detection during 1961-2005 applying double accumulative curve method, mean shift t-test method and Mann-Kendall mutation test technique. Based on the establishment of a rainfall-runoff empirical statistical model, impacts and the runoff-reducing effects of water conservancy and soil conservation measures on runoff reduction were evaluated quantitatively. The major results could be summarized as follows： （1） The annual precipitation in the drainage basin tends to decrease while the runoff has declined markedly since the 1960s, the average annual runoff from 1991 to 2000 was only 90.9% in proportion to that from 1961 to 1970. （2） The annual runoff variations in the drainage basin are significantly related to human activities. （3） During 1981-1990, 1991-2000, 2001-2005 and 1981-2005, the average annual runoff reduction amounts were 1.15×10^8, 0.28×10^8, 1.10×10^8 and 0.79×10^8 m^3 respectively and the average annual runoff-reducing effects were 31.99%, 7.13%, 40.71% and 23.79% accordingly. Runoff-reducing effects by water conservancy and soil conservation measures are more prominent in the low water period.