Time filter

Source Type

Wang Y.-L.,Chinese Academy of Sciences | Wang Y.-L.,University of Chinese Academy of Sciences | Liu L.-C.,Chinese Academy of Sciences | Gao Y.-H.,Chinese Academy of Sciences | And 5 more authors.
Chinese Journal of Applied Ecology | Year: 2016

Water is a major limiting factor for plant growth in arid and semi-arid regions. To find out the main sources of water for two artificial sand-fixation plants (Caragana korshinskii and Artemisia ordosica), we analyzed the characteristics of hydrogen and oxygen stable isotopes in water molecules of rainfall, soil water and xylem water. To analyze water sources of these two plants, we used a direct comparison method and a multi-variate mixed linear model. The results showed that an equation of local meteoric water line in Shapotou was δD=7.83δ18O+5.64 (R2=0.91). The value for rainfall δ18O varied during plant-growing season, which was higher in the beginning and end of growing season, and lower in the peak of growing season. The value for soil water δ18O in the upper layers changed dramatically. The change range became smaller in the deeper soil layer. C. korshinskii had a greater efficiency (56.1%) in utilizing soil water in 40-80 cm soil layer. A. ordosica had a utilizing efficiency of 56.4% in 20-60 cm soil layer. A week after rain event, C. korshinskii and A. ordosica showed a higher efficiency in upper soil water. C. korshinskii showed an increase of 12.5% in utilizing soil water in 0-40 cm soil layer and A. ordosicas showed an increase of 10% in utilizing soil water in 0-20 cm layer. These results suggested that C. korshinskii and A. ordosica changed their water use strategy after large rainfall events, which might enable them to more easily adapt to arid environment. © 2016, Science Press. All right reserved.

Jin L.,China Agricultural University | Jin L.,Heilongjiang Academy of Agriculture science | Hu K.,China Agricultural University | Deelstra J.,Institute for Agricultural and Environmental Research Bioforsk As | And 3 more authors.
Acta Agriculturae Scandinavica Section B: Soil and Plant Science | Year: 2014

Water scarcity and nitrate contamination in groundwater are serious problems in the North China Plain (NCP). The objective of this study was to compare the effects of farmer's practice and optimal water and nitrogen management on nitrate leaching, and water and nitrogen use efficiencies (WUE, NUE) during winter wheat season in the NCP. A winter wheat experiment with four treatments (traditional irrigation plus traditional fertilizer, W1N1; traditional irrigation plus optimal fertilizer, W1N2; optimal irrigation plus traditional fertilizer, W2N1; optimal irrigation plus optimal fertilizer, W2N2) was conducted from October 1999 to June 2001 in Beijing suburban. The soil-plant system, water and solute transport model was calibrated and validated based on the data collected from the experimental field, then the model was used to simulate the water movement, nitrogen (N) transport, and crop growth process. The results showed that the simulated soil water content, nitrate concentration in the soil profile, leaf area index, crop N uptake, and grain yield were all in good agreement with the measured data. The simulated results indicated that the improved management of water and fertilizer practice could increase crop yield, and reduce water drainage, nitrate leaching, and gaseous N loss compared to farmers' practice. WUE and NUE under improved practice were 1.36 kg m-3 and 34.9 kg kg-1N-1 in 2000, 1.07 kg m-3 and 31.5 kg kg-1N-1 in 2001, respectively. Compared to farmers' practice, the optimal management practice can save water about 4-19%, water drainage decreased 50-65%, N leaching reduced over 90% and gaseous N loss decreased about 70%, at same time leading to an increase in WUE and NUE by 10.6% and 10.3% in 2000, 64.5% and 98.3% in 2001, respectively. © 2014 Taylor & Francis.

Han J.,Shaanxi Province Real Estate Development Corporation | Han J.,Key Laboratory of Degraded and Unused Land Consolidation Engineering | Han J.,Engineering Research Center for Land Consolidation of Shaanxi Province | Xie J.,Engineering Research Center for Land Consolidation of Shaanxi Province | And 3 more authors.
Chinese Geographical Science | Year: 2012

This paper analyzed the water-retention mechanism of feldspathic sandstone (fine- (< 1 mm diam.) and gravel-sized (2.3 cm diam.) in Mu Us Sandy Land, Northwest China. The objective of this study is to study the effect of feldspathic sandstone amendment on water retention in sandy land. The results showed that as the proportion of fine feldspathic sandstone in the sandy land soil increased, the soil texture changed from sand to silt loam, the capillary porosity gradually increased from 26.3% to 44.9%, and the soil saturated hydraulic conductivity decreased from 7.10 mm/min to 0.07 mm/min. Feldspathic sandstone gravel formed micro-reservoirs in the sandy land soil, playing the role of a 'water absorbent' and 'water retaining agent' in sandy land. Amendment with feldspathic sandstone can increase water retention in the arable layer of sandy land by 67%. This study provides a theoretical basis for the amelioration of sandy land on a large scale. It can be concluded that amendment with feldspathic sandstone can improve the physical properties of sandy land soil and increase soil water retention. © 2012 Science Press, Northeast Institute of Geography and Agroecology, CAS and Springer-Verlag Berlin Heidelberg.

Han J.,Shaanxi Land Construction Group Co. | Han J.,Key Laboratory of Degraded and Unused Land Consolidation Engineering | Han J.,Engineering Research Center for Land Consolidation | Zhang Y.,Shaanxi Land Construction Group Co. | And 2 more authors.
Land Use Policy | Year: 2014

Based on the relationship between land policy and land engineering, we defined the concept of 'land engineering' and its contents, and demonstrated the significance of the establishment of land engineering. On the one hand, the land policy guided the development of the land engineering. On the other hand, the land engineering is an important means to improve and execute the land policy. The contents of land engineering are summarized as follows: (1) conversion of non-agricultural land into agricultural land; (2) conversion of low standard use land into a high standard use land; (3) conversion of current land into human construction use; (4) conversion of polluted and damaged land into usable land. Our study provides scientific support for the efficient utilization of land resources. © 2013 Elsevier Ltd.

Liu Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Liu Y.,Key Laboratory of Degraded and Unused Land Consolidation Engineering | Yang R.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Yang R.,University of Chinese Academy of Sciences | And 5 more authors.
Land Use Policy | Year: 2014

Based on surveys on rural land-use change at village scale in Yucheng City, Shandong province, this paper presents how land-use change takes place in response to inhibitive institutional forces in light of an outmoded land ownership system and unreasonable land use rights administration, and discusses it in the broader social context of industrialization, rural depopulation, a dual-track land market, and land use legislation. Spatial comparison of land use maps interpreted from aerial photographs in different period unveils a decrease in arable land for farming, and an increase in rural settlements, facilities land and unused land. Despite rural depopulation, rural settlements area nearly tripled during 1967-2008. Nearly all newly gained non-agricultural land originated from farmland at the village fringe while formerly facilities land and unused land had been converted to residential use and it was abandoned later. Thus, the destructive farmland conversion from productive use to non-agricultural uses took place at multiple stages. Questionnaire survey of 1650 households in 48 villages in Yucheng City indicated that 41% of the households had multiple dwellings, even though some of them are not occupied or even ruined. This finding may damp the rosy picture of the reportedly slowdown in China's farmland reduction in recent years as these destructive changes are too small to detect from satellite imagery, and it will also provide a practical scientific basis for constituting more strict farmland protection objectives and strategies for China in the near future. In order to hold back the destructive conversion trend from farmland to non-agricultural uses, the authors argue that policy and institution innovation concerning land use and urban-rural development in China needs feature highly in the government's agenda. © 2013 Elsevier Ltd.

Discover hidden collaborations