https://lirias.kuleuven.be/retrieve/78844

Deficit irrigation as an on-farm strategy to maximize crop water productivity in dry areas

Water shortage in China, particularly in the north and northwest of China, is very serious. The region accounts for half of the total area of China, but has less than 20% of total national available water resources. While the water shortage in this region is severe, irrigation water use efficiency is only about 40%, with a typical agricultural water use efficiency of about 0.46 kg m(-3). Excessive irrigation in Ningxia and Inner Mongolia has had a significant influence on downstream water users along the Yellow River. It is widely believed that an increase in the agricultural water use efficiency is the key to mitigating water shortage and reducing environmental problems. This paper reviews water-saving agricultural systems and approaches to improve agricultural water use efficiency in the and and semiarid areas of China. The paper will cover biological mechanisms of water-saving agriculture and water-saving irrigation technologies, including low pressure irrigation, furrow irrigation, plastic mulches, drip irrigation under plastic, rainfall harvesting and terracing, In addition, the paper addresses the compensatory effect of limited irrigation and fertilizer supplementation on water use efficiency and highlights the need to breed new varieties for high water use efficiency. Considerable potential for further improvement in agricultural water use efficiency in the region depends on effective conservation of moisture and efficient use of the limited water. (c) 2005 Elsevier B.V. All rights reserved.

Improving Agricultural Water Use Efficiency in Arid and Semi-arid Areas of China

http://www.cropscience.org.au/icsc2004/pdf/2085_deng.pdf

Improving agricultural water use efficiency in arid and semiarid areas of China

http://ww.nuritagam.com/Papers/2014-Kool-et-al-AFM-ET%20partitioning%20review.pdf

A review of approaches for evapotranspiration partitioning

Evapotranspiration (ET) is the process by which liquid water becomes water vapor and energetically this accounts for much of incoming solar radiation. If this ET did not occur temperatures would be higher, so understanding ET trends is crucial to predict future temperatures. Recent studies have reported prolonged declines in ET in recent decades, although these declines may relate to climate variability. Here, we used a well-validated diagnostic model to estimate daily ET during 1981-2012, and its three components: transpiration from vegetation (Et), direct evaporation from the soil (Es) and vaporization of intercepted rainfall from vegetation (Ei). During this period, ET over land has increased significantly (p < 0.01), caused by increases in Et and Ei, which are partially counteracted by Es decreasing. These contrasting trends are primarily driven by increases in vegetation leaf area index, dominated by greening. The overall increase in Et over land is about twofold of the decrease in Es. These opposing trends are not simulated by most Coupled Model Intercomparison Project phase 5 (CMIP5) models, and highlight the importance of realistically representing vegetation changes in earth system models for predicting future changes in the energy and water cycle.

https://biblio.ugent.be/publication/7033679/file/7033688.pdf

Multi-decadal trends in global terrestrial evapotranspiration and its components

Effects of limited irrigation on yield and water use efficiency of winter wheat in the Loess Plateau of China

Crop coefficient and ratio of transpiration to evapotranspiration of winter wheat and maize in a semi-humid region

Vegetation change is of significant concern because it plays a crucial role in the global carbon cycle and climate. Many studies have examined recent changes in vegetation growth and the associated drivers. These drivers include both natural and human activities, but few studies have identified the regulation factors. By employing normalized difference vegetation index (NDVI) data, we analyzed the spatiotemporal pattern of vegetation change in China and then explored the driving factors. It was found that the overall greening of China has improved significantly, especially in the Loess Plateau and southwest China. The Yangtze River Delta and Bohai Rim, however, have not seen as much growth. Natural conditions are conducive to vegetation growth. Although socioeconomic development will be more beneficial for vegetation restoration, the current level and speed of development have a negative effect on vegetation. The regulation factors are considered separately since they affect both directly and indirectly. Regulation factors have accelerated vegetation growth. By understanding the factors affecting the current vegetation growth, we can provide a guide for future vegetation recovery in China and other similar countries. 

http://www.geogsci.com/CN/article/downloadArticleFile.do?attachType=PDF&id=53558

Regulation factors driving vegetation changes in China during the past 20 years

Functional zoning provides a basis for establishing a regional development layout with clear functions, reasonable division of labor, and complementary advantages. In the process of urban development, a large number of behaviors such as occupying ecological land and generating a lot of pollution cause damage to the urban ecological environment. Functional zoning of the ecological environment has become an important tool used by the local and central governments to establish a harmonious relationship between socio-economic welfare and the ecological environment in recent years. Guided by the concepts and principles of ecological function zoning, this study applies and extends the methodological approach of ecological function zoning to the scale of urban space. Based on consideration of an evaluation of ecological environment sensitivity, ecosystem service function importance, and socio-economic coercion, this paper divides urban space into four types, namely: ecological environment restoration zone, ecological economy bearing zone, ecological environment preservation zone, and ecological environment protection zone, utilizing a mutually exclusive matrix classification. Taking Taizhou in Jiangsu Province as a pilot study, this paper verifies the actual application of a theoretical model and its technicalities, thus advancing the general case for function zoning of the ecological environment. Furthermore, it outlines measures for ecological environment protection and the industrial development orientation of each function area, thus providing a scientific basis for Taizhou’s ecological city development and construction.

/pdf/evaluation-and-functional-zoning-of-the-ecological-2jjnomue.pdf

Evaluation and Functional Zoning of the Ecological Environment in Urban Space—A Case Study of Taizhou, China

Blue–green infrastructure provides a variety of ecosystem services and is becoming an increasingly vital part of urban ecosystem protection. It is an ecological facility for ecological conservation and environmental protection, and a foundation for realizing people’s needs for a better life. This study selects indicators from four dimensions: social, economic, environmental, and ecological, and the demand for blue–green infrastructure is assessed comprehensively. The results show that: (1) the demand for blue–green infrastructure varies spatially with the development of the city; (2) the total demand for blue–green infrastructure in Nanjing from 2000 to 2020 shows a pattern of “high in the center and low in the periphery”; (3) the level of economic development, urban spatial pattern, and decision management orientation have different degrees of influence on the demand for blue–green infrastructure, with the urban spatial pattern having the greatest impact. Therefore, in the future, blue–green infrastructure should be optimized by taking into account the spatial characteristics of demand in Nanjing.

/pdf/socioeconomic-factors-influence-the-spatial-and-temporal-dz9gvgft.pdf

Binjie Gu

Papers

Effects of limited irrigation on yield and water use efficiency of winter wheat in the Loess Plateau of China

Crop coefficient and ratio of transpiration to evapotranspiration of winter wheat and maize in a semi-humid region

Regulation factors driving vegetation changes in China during the past 20 years

Evaluation and Functional Zoning of the Ecological Environment in Urban Space—A Case Study of Taizhou, China

Socioeconomic Factors Influence the Spatial and Temporal Distribution of Blue–Green Infrastructure Demand: A Case of Nanjing City