Response of relative sap flow to meteorological factors under different soil moisture conditions in rainfed jujube (Ziziphus jujuba Mill.) plantations in semiarid Northwest China

Wei

Chen

et al. 2017

Ecological Engineering

a b s t r a c tTerracing has long been considered one of the most effective measures for soil water conservation and site improvement. However, few studies regarding the quantitative effects of terracing on soil water dynamics and vegetation water use efficiency were reported. To fill these knowledge gaps, in this study, soil water content and canopy transpiration from 2014 to 2015 were monitored in both terrace and slope environments in the semiarid Loess Plateau of China. Results showed that terracing had positive influences on soil water content among layers. Mean soil water content of the terrace site was 25.4% and 13.7% higher than that in the slope site in 2014 and 2015, and canopy transpiration at the terrace site increased by 9.1% and 4.8%, respectively. Canopy conductance at the terrace site was 3.9% higher than that at the slope site and it decreased logarithmically with the increase of vapor pressure deficit. This study highlighted the critical role of terracing in soil-water improvement and water-stress mitigation in semiarid environments. Thus, terracing has the potential to enhance sustainable vegetation restoration in water-limited regions.

Section: Effects Of Terracing On Canopy Transpirationsupporting

confidence: 80%

Section: Effects Of Terracing On Canopy Transpirationmentioning

confidence: 99%

Effects of terracing on soil water and canopy transpiration of Pinus tabulaeformis in the Loess Plateau of China

Wei

Chen

et al. 2017

Ecological Engineering

“…Chen et al reported that low transpiration was governed by strict physiological regulation and daily Vpd exceeding 1 kPa [12]. Sap flow velocity of Qinghai spruce was heightened by increasing the Vpd when Vpd < 1.4 kPa [10].…”

Section: Discussionmentioning

confidence: 99%

“…For example, in a comparative study, the effect of a flat-roof screen house on banana transpiration showed that reduction in transpiration in the screen house is mainly due to the combined reductions of wind speed and global radiation [11]. There were significant differences in sap flow dynamics of a drought-tolerant plant between the two periods of the day (0:00-15:00 and the remainder) due to the meteorological factors [12]. In the future, climate change likely will increase air temperature, and its variation may be accompanied by similar changes in vapor pressure deficit (V pd ), which would influence the canopy transpiration [6].…”

Section: Introductionmentioning

confidence: 99%

The Relationship between Sap Flow Density and Environmental Factors in the Yangtze River Delta Region of China

Liu

Zhuang

et al. 2017

Forests

Abstract:Canopy transpiration is an important component of evapotranspiration, integrating physical and biological processes within the water and energy cycles of forests. Quercus acutissima and Cunninghamia lanceolata are two important, fast-growing and commercial tree species that have been extensively used for vegetation restoration, water conservation and building artificial forests in the Yangtze River Delta region of China. The primary objective of this study was to characterize sap flow densities of the two species by comparing daytime and nocturnal sap flow patterns and their relationships with environmental factors. Sap flow densities (S d ) were measured between September 2012 and August 2013 using the commercially-available thermal dissipation probes. Hourly meteorological data were measured in an open field, located 200 m away from the study site, including photosynthetically-active radiation (P ar ), air temperature (T a ), relative air humidity (R h ), vapor pressure deficit (V pd ) and precipitation (P). Soil water content (S wc ) data were logged hourly in different layers at Q. acutissima and C. lanceolata forests. Results indicated that the mean S d in summer was higher than that in spring and autumn. Both the S d of Q. acutissima and C. lanceolata showed distinct diurnal patterns. Nocturnal sap flow densities (S dn ) were noticeable, and both species followed similar declining patterns during our study period. The daytime sap flow density (S dd ) was more sensitive to environmental factors than S dn . Sap flow density was significant linearly correlated with P ar , V pd and T a , and P ar and V pd explained the greatest amount of variation in daytime sap flow of Q. acutissima and C. lanceolata, respectively. Our study will enrich knowledge of plantation forest physical and biological processes and provide valuable information for plantation forest management in the Yangtze River Delta region of China.

“…In addition to soil moisture, the low regression coefficient 214 can be attributed to the influence of various environmental factors (Bosch et al, 2014;Brito et al, 215 2015;Chen et al, 2014c). Among these factors, VPD and solar radiation can trigger a timely 216 response in transpiration, while the influence of soil water is reflected over a longer temporal 217 scale (Chen et al, 2014a;Shen et al, 2015). 218…”

mentioning

confidence: 99%

Effects of terracing on soil water and canopy transpiration of Chinese pine plantation in the Loess Plateau, China

Wei

Chen

et al. 2016

Preprint

1Terracing has long been considered one of the most effective measures for soil water 2 conservation and site improvement. However, the quantitative effects of terracing on soil water 3 dynamics and vegetation water use have not been reported. To fill these knowledge gaps, in this 4 study, soil water content and canopy transpiration were monitored in both terrace and slope 5 environments in the semiarid Loess Plateau of China in 2014 and 2015. Results showed that 6 terracing increased soil water content of different soil layers. Mean soil water content of the 7 terrace site was 25.4% and 13.7% higher than that in the slope site in 2014 and 2015, and canopy 8 transpiration at the terrace site increased by 9.1% and 4.8%, respectively. Canopy conductance at 9 the terrace site was 3.9% higher than that at the slope site and it decreased logarithmically with 10 vapor pressure deficit. This study highlighted the critical role of terracing in increasing the soil 11 water content and mitigating water stress in semiarid environments. Thus, terracing has the 12 potential to enhance sustainable vegetation restoration in water-limited regions. 13