It has been widely accepted that there is a close relationship between the land use type and water quality. There have been some researches on this relationship from the perspective of the spatial configuration of land use in recent years. This study aims to analyze the influence of various land use types on the water quality within the Chaohu Lake Basin based on the water quality monitoring data and RS data from 2000 to 2008, with the small watershed as the basic unit of analysis. The results indicated that there was significant negative correlation between forest land and grassland and the water pollution, and the built-up area had negative impacts on the water quality, while the influence of the cultivated land on the water quality was very complex. Besides, the impacts of the landscape diversity on the indicators of water quality within the watershed were also analyzed, the result of which indicated there was a significant negative relationship between them. The results can provide important scientific reference for the local land use optimization and water pollution control and guidance for the formulation of policies to coordinate the exploitation and protection of the water resource.

SignificanceChanges in land use, climate, and agricultural technologies affect pest severity and management. We analyzed long-term longitudinal data (1991–2015) on three major cotton pests for 51 Chinese counties. Bacillus thuringiensis (Bt) insect-resistant cotton had pervasive effects on the whole pest complex and its management. Adoption resulted in major reductions in insecticide use against bollworm. The resulting restoration of aphid biocontrol decreased aphid severity. Mirid bug severity increased, aided by higher May temperatures and reduced insecticide sprays against bollworm. Landscape effects on pest severity varied between species. Farmers sprayed at nondamaging infestation levels. Findings support Bt-based plant resistance as a component of integrated pest management (IPM) but highlight the potential for unintended outcomes for the whole pest complex and the importance of climate change.

Abstract. The purpose of this study is to examine the conversions of forests in Northeast China during 1988-2005 by using a 1-km area percentage data model (1-km APDM) with remote sensing data and to find the spatiotemporal characteristics of land conversions between forests and other land uses/covers and internal conversions between forest cover types. Data were derived from Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) images of bands 3, 5, and 4 acquired in 1988, 1995, 2000, and 2005. Research results show that in the period between 1988 and 2005, the forest area in Northeast China underwent dramatic changes, and 4.11 million ha of forest area was aggregately lost because of the conversions of forests to other land uses/covers; at the same time, the forest area also gained 2.00 million ha because of the conversions from other land uses/covers to forests. The results also demonstrate the forest degradation resulting from the conversions between different forest cover types. This research demonstrates the feasibility and importance of using the 1-km APDM at a finer resolution to trace the spatiotemporal patterns of the forest conversions.

a b s t r a c tSerious water scarcity, low water-use efficiency, and over-exploitation of underground water have hindered socio-economic development and led to environmental degradation in the Heihe River basin, northwestern China. Price leveraging is an important tool in water demand management, and it is considered to be effective in promoting water conservation and improving water use efficiency on the premise that water demand is elastic. In the present study, we examine whether price is an effective and applicable instrument for restraining the increasing demand for agricultural irrigation water in the middle reaches of the Heihe River basin and how will it affect farmers' decisions on irrigation and crop structure. Specifically, the price elasticity of agricultural water demand was estimated based on the irrigation water demand function. The results show that the agricultural irrigation water price is statistically significant, but its elasticity is very low under current low water price. Price leverage cannot play a significant role in the context of the current pricing regime and farmers' response to price increase is intrinsically weak. To create incentives for conserving water and improving irrigation efficiency, price mechanism should be accompanied with clearly defined and legally enforceable water rights, restricted water quota measures, and reform of water authorities and water-user associations. Furthermore, increases of surface irrigation water price may lead to the over-withdrawal of groundwater, consequently, effective groundwater licensing and levying must take place to limit the total volume of groundwater withdrawal. In all, improving irrigation efficiency through better management and the adoption of water-saving technologies is the ultimate way to deal with the challenges facing irrigated agriculture in the middle reaches of the Heihe River basin.

This paper presents a hybrid algorithm for separation of two simultaneous partial discharge (PD) sources of oil-paper insulation based on S transform (ST) and affinity propagation clustering (APC). Similarities between PD pulses are acquired by comparisonsof the corresponding ST-amplitude (STA) matrices, which are input of APC to realize the PD pulses separation and obtain two sub-groups of PD pulses having similar time-frequency characteristics. A classification-based model for separation results validation are developed using a support vector machine with particle swarm optimization (PSO-SVM) classifier and 27 phase-resolved partial discharge (PRPD) statistical features. Artificial defect models are made to simulate two PD sources simultaneously active. Several PD data of different two simultaneous PD sources are acquired in laboratory and adopted for algorithm testing. It is shown that ST computes very fast and is suitable for online PD applications. The separation results of PD data produced in laboratory are verified by the developed validation model, which demonstrate that ST combined with APC can effectively eliminate pulse-shaped noises (PSN) and separate pulses of two simultaneous PD sources. Comparisons with typical separation methods from the state of the art provide better separation performance of the proposed ST combined with APC algorithm for two simultaneous PD sources. The obtained results in this work provide a solid basis for the data mining technique that can be used to facilitate PD diagnosis of transformers.

a b s t r a c tThe water-use efficiency has direct impacts on the water consumption of agriculture production and is vital to water conservation at both local and regional extent. The agricultural water-use efficiency is a critical indicator that reflects the effective water allocation and water productivity improvement among different agricultural sectors. Taking the Heihe River Basin as the case study area, this study explores the changing trajectories of agricultural water use based on the inputeoutput data of 2003e2012, and estimates the water-use efficiency with Data Envelopment Analysis, Malmquist Total Productivity Index and the decomposition of total factor productivity. Further, the influence of driving factors on the wateruse efficiency is analyzed with the Tobit model. The research results indicate that the average agricultural water-use efficiency in different counties is all lower than 1 during 2003e2012, indicating that there is still improvement space in the agricultural water-use efficiency. In addition, there is obvious heterogeneity in the agricultural water-use efficiency among different counties, especially prior to 2009. The research results from the Tobit model indicate that agricultural investment and production, economic growth, industrial restructuring and agricultural plants structural adjustment have significant influence on the agricultural water-use efficiency. The research results can provide significant references for agricultural water-use management in the middle reaches of the Heihe River Basin and other similar regions in Northwest China.

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a b s t r a c tIn China, the provinces of Shandong and Henan are the leading provinces for grain production and also have the highest populations. In this study, we quantitatively analyze the impact of the two primary factors that indicate rural restructuring (namely, an increase in labor-and capital-augmenting technical change, represented by labor and capital productivity) on wheat production in Shandong and Henan provinces, and the consequent effects on exported and imported wheat volumes in other provinces through to 2020. For the analysis, we use The Enormous Regional Model (TERM), an established multiregion computable general equilibrium model. The results show that the magnitude of change generated by the increase in labor productivity is larger than that generated by the increase in capital productivity. Therefore, great importance should be attached not only to increasing capital technical change but also improving labor technical change. This study also reveals that regional competitive industry can easily shape absolute competition superiority, which consequently exerts a large impact on the homogeneity of products. Rural China is moving into a critical stage of restructuring, and therefore the government should provide rational top-down guidance. The central government should avoid adopting a "one size fits all" policy and simply supporting a single industry or particular development patterns. Rural China should form stable, sustainable, and specialized agricultural production arranged by geographic areas, which would not only guarantee China's food security, but also improve the nation's competitive capacity in the international market.