The impacts of human activities on the water–land environment of the Shiyang River basin, an arid region in northwest China / Les impacts des activités humaines sur l’environnement pédo-hydrologique du bassin de la Rivière Shiyang, une région aride du nord-ouest de la Chine

Abstract

(2004) The impacts of human activities on the water-land environment of the Shiyang River basin, an arid region in northwest China / Les impacts des activités humaines sur l'environnement pédo-hydrologique du bassin de la Rivière Shiyang, une région aride du nord-ouest de la Chine, Hydrological Sciences Journal, 49:3, Abstract The Shiyang River basin is a typical interior river basin that faces water shortage and environmental deterioration in the arid northwest of China. Due to its arid climate, limited water resources and some inappropriate water-related human activities, the area has developed serious loss of vegetation, and gradual soil salinization and desertification, which have greatly impeded the sustainable development of agriculture and life in this region. In this paper, the impacts of human activities on the water-soil environment in Shiyang River basin are analysed in terms of precipitation, runoff in branches of the river, inflow into lower reaches, water conveyance efficiency of the canal system and irrigation water use efficiency in the field, replenishment and exploitation of groundwater resources, soil salinization, vegetation cover and the speed of desertification. The results show that human activities and global climate change have no significant influence on the precipitation, but the total annual runoff in eight branch rivers showed a significant decrease over the years. The proportion of water use in the upper and middle reaches compared to the lower reach was increased from 1:0.57 in the 1960s, to 1:0.27 in the 1970s and 1:0.09 in the 1990s. A reduction of about 74% in the river inflow to the lower reaches and a 15-m drop in the groundwater table have occurred during the last four decades. Strategies for improving the water-soil environment of the basin, such as the protection of the water resources of the Qilian Mountains, sustainable use of water resources, maintenance of the balance between land and water resources, development of water-saving agriculture, diverting of water from other rivers and control of soil desertification, are proposed. The objective of this paper is to provide guidelines for reconstruction of the sustainable water management and development of agriculture in this region.

Wheat straw mulching with fertilizer nitrogen: An approach for improving soil water storage and maize crop productivity

“…The present study indicated that surface FS + N regime conserves higher soil moisture across the growing season principally during early growth stages compared with CK. The surface application of mulching acts as a physical barrier for reducing evaporation losses, reduces rainfall water runoff and thus increases water storage and slows down air convection on the soil surface (Kang et al 2004, Fan et al 2013. Furthermore, the FS + N regime enhanced soil water storage, so that CK -no straw mulching and no nitrogen; N -no straw mulching and 172 kg N/ha; HS + N -half straw mulching at a rate of 2500 kg/ha of wheat straw with 172 kg N/ha; FS + N -full straw at a rate of 5000 kg/ha of wheat straw with 172 kg N/ha.…”

Mountain-river runoff components and their role in the seasonal development of desert-oases in northwest China

“…Most of the precipitation occurs during the June-through-August period of the year. Mean annual runoff in the Shiyang River is about 15.75 Â 10 8 m 3 yr À1 , whereas in the Hei River it is about 37.7 Â 10 8 m 3 yr À1 (Kang et al, 2009).…”

“…Long term average data (1950e2000) show that precipitation and potential ET (based on calculations with the Penman-Monteith equation; Monteith, 1965;Penman, 1948) in the deserts are approximately 80e150 mm yr À1 and 2300e2600 mm yr À1 , respectively. Corresponding figures for the mountainous regions are 300e600 mm yr À1 for precipitation and about 700 mm yr À1 for potential ET (Akiyama et al, 2007;Chen et al, 2005;Gates et al, 2008;Huo et al, 2008;Kang et al, 2009;Ma et al, 2013;Tong et al, 2007;Wang and Cheng, 1999;Wang and Zhao, 2011;Zang et al, 2012). Most of the precipitation occurs during the June-through-August period of the year.…”

Relating seasonal dynamics of enhanced vegetation index to the recycling of water in two endorheic river basins in north-west China

“…Most of the precipitation occurs during June to August; about 94 % of water delivered from the mountains to lowland oases is through surface runoff. Average annual runoff in the Shiyang River is about 15.8 × 10 8 m 3 yr −1 , whereas in the Hei River it is about 37.7 × 10 8 m 3 yr −1 (Kang et al, 2009). …”