Regional spatial pattern of deep soil water content and its influencing factors

2012 ◽  
Vol 57 (2) ◽  
pp. 265-281 ◽  
Author(s):  
Yunqiang Wang ◽  
Ming'an Shao ◽  
Zhipeng Liu ◽  
David N. Warrington
Keyword(s):  
Spatial Pattern ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Influencing Factors ◽  
Deep Soil

scholarly journals Wheat root dynamics as affected by landscape position

2006 ◽  
Vol 86 (3) ◽  
pp. 523-531 ◽  
Author(s):  
R M.A. Block ◽  
K C.J. Van Rees
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Root Length ◽  
Landscape Position ◽  
Root Production ◽  
Root Dynamics ◽  
Deep Soil ◽  
Wheat Roots ◽  
Shoulder Position

The effects of landscape position on root production and mortality were assessed in a 90-cm-deep soil profile at a shoulder and footslope landscape position seeded to spring wheat (Triticum aestivum L.). Root length was measured over eight sampling dates using a minirhizotron system, and soil water content and temperature were recorded at various depths at each landscape position. The shoulder position was drier than the footslope position in the upper 30 cm due to a greater frequency and duration of soil temperatures > 20°C, and at depth (> 75 cm). Mean root length was greatest at the footslope position and was concentrated in the upper 20 cm of the profile, while the shoulder position had the greatest root length at the 40- to 60-cm depth. Mean daily root production peaked at 5.0 to 6.0 m m-2 d-1 at the 43rd day after planting (DAP) for both landscape positions, which corresponded to the time of booting. Daily rates for root mortality ranged from 0.5 to 2.5 m m-2 d-1. Soil water content and daily root production at the 10-cm depth were positively correlated at both landscape positions. Information on landscape position differences in root productivity and mortality could help to improve placement of inorganic fertilizers, and estimation of below-ground carbon sequestration. Key words: Wheat, roots, minirhizotron, landscape position

scholarly journals Dynamics of Soil Water Content Across Different Landscapes in a Typical Desert-Oasis Ecotone

2020 ◽  
Vol 8 ◽  
Author(s):  
Guohua Wang ◽  
Qianqian Gou ◽  
Yulian Hao ◽  
Huimin Zhao ◽  
Xiafang Zhang
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Groundwater Resources ◽  
Time Lag ◽  
Northwest China ◽  
Deep Soil ◽  
Deep Layers ◽  
Desert Oasis

An understanding of soil water content dynamics is important for vegetation restoration in an arid desert-oasis ecotone under different landscapes. In this study, the dynamics of soil water content under three typical landscapes (i.e., desert, sand-binding shrubland, and farmland shelter woodland) were investigated in the Hexi Corridor, northwest China, during the growing season from 2002 to 2013. The results showed that the soil water content in the deep layers decreased from 20–30% to a stable low level of 3–5% in the desert and shrubland. For the farmland shelter woodland, the soil water content at the deep layers also decreased, but the decrease rate was much smaller than the desert and shrubland. The decrease of soil water content in the deep soil layers among desert–shrubland–woodland was strongly associated with the increase of groundwater depths. The greatest increase of groundwater depths mainly occurred during 2008–2011, while the largest decrease of soil water content took place during the years 2009–2011, with a time-lag in response to increase in groundwater depths. This study provides new insight into the long-term dynamics of soil water content in a typical desert oasis ecotone under different landscape components from the influence of overexploiting groundwater that cannot be inferred from a short-term study. The findings demonstrate that the sharp increase of groundwater depths could be the main reason behind the reduction of soil water content in the clay interlayers, and sustainable development of groundwater resources exploitation is very important for the management of desert-oasis ecotone from a long-term perspective.

scholarly journals Changes in Deep Soil Water Content in the Process of Large-Scale Apple Tree Planting on the Loess Tableland of China

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 123
Author(s):  
Yaping Wang ◽  
Weiming Yan ◽  
Xiaoyang Han ◽  
Feifei Pan ◽  
Liping Cheng ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Tree Planting ◽  
Planting Density ◽  
Annual Precipitation ◽  
Stand Age ◽  
Deep Soil ◽  
Apple Trees ◽  
Soil Desiccation

Soil water has become a major limiting factor in agriculture and forestry development on the Loess Plateau of China. In the past 20–30 years, large areas of apple orchards have been built in this region, which have resulted in excessive consumption of deep soil water and soil desiccation. To evaluate the effects of orchard development on deep soil water content (SWC), a meta-analysis of 162 sampling sites on the loess tableland from 44 peer-reviewed publications was conducted in this study. The results showed that the deep SWC in orchards depended on stand age, planting density and annual precipitation. In regions with 550–600 mm precipitation, the orchard with lower planting density showed no soil desiccation in young and early fruiting stages, while deep soil (>2 m) desiccation occurred in full fruiting and old orchards. The effect of planting density on deep SWC varied with stand age. There were significant differences in SWC among different planting densities in early fruiting orchards (p < 0.05), in which soil desiccation occurred in orchards with higher planting density. However, with the continuous consumption of soil water by apple trees, deep soil desiccation occurred in old orchards regardless of planting density. Further, affected by the spatial variation of annual precipitation, deep SWC in orchards significantly decreased with annual precipitation from 650 to 500 mm among the 44 study sites (p < 0.05). Our results suggest that the planting density should be reasonably regulated on the level of annual precipitation, and apple trees need to be pruned appropriately with a goal of moderate productivity, so as to achieve the sustainable use of regional water resources, food security and economic development.

Effects of soil freezing stress on sap flow and sugar content of mature sugar maples (Acersaccharum)

1995 ◽  
Vol 25 (4) ◽  
pp. 577-587 ◽  
Author(s):  
Gilles Robitaille ◽  
Robert Boutin ◽  
Denis Lachance
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Flow Rate ◽  
Sap Flow ◽  
Sugar Content ◽  
Soil Freezing ◽  
Freezing Stress ◽  
Deep Soil ◽  
Sugar Maples

Mature dominant and codominant sugar maples (Acersaccharum Marsh.) at the Duchesnay Experimental Forest (Quebec, Canada) were subjected to deep soil freezing (DF), superficial freezing (SF), and superficial freezing with drought (SFD) during the 1990–1991 and 1991–1992 seasons. Soil temperatures below the DF trees reached lows of −6 °C at 20 cm depth and were significantly lower than the controls. Compared with the controls, unfrozen soil water content was lower (10%, v/v) below the DF trees. During the dry summer of 1991, soil water content remained high below the DF trees at 30% (v/v); controls reached 10% (v/v). Deep frost treated trees had significantly lower sap flow rates, total sap volume, and less total sugar per tree than other treatments for at least 2 years after treatment. These lower values were likely related to the condition of the DF trees (increased canopy transparency; branch dieback). Percent sugar was significantly higher in the DF trees in 1992. Drought did not seem to have a significant effect on sap flow rate as values obtained for 1991 to 1993 followed the same pattern as that for the control trees. Sap in SF trees tended to flow more than in control trees in 1991. Sap in DF-treated trees that did not show visual symptoms of dieback had a lower flow rate than control trees. Soil freezing, which is concomitant with severe reductions in soil water availability, had a negative effect on spring sap flow. A sufficient source of soil water at the moment of stem recharge seems to be critical during the conditioning period to maintain stem pressure and sap flow.

scholarly journals Sustainability of Abandoned Slopes in the Hill and Gully Loess Plateau Region Considering Deep Soil Water

2018 ◽  
Vol 10 (7) ◽  
pp. 2287 ◽  
Author(s):  
Weijie Yu ◽  
Juying Jiao
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Loess Plateau ◽  
Soil Layer ◽  
Deep Soil ◽  
Plateau Region ◽  
Soil Desiccation ◽  
Deep Soil Layer ◽  
The Hill

Soil desiccation of the deep soil layer is considered one of the main limiting factors to achieving sustainable development of ecosystems in the hill and gully Loess Plateau region. In this study, slope croplands were selected as the control, and deep soil water was studied on abandoned slopes, including natural abandoned slopes, Robinia pseudoacacia plantations, and Caragana korshinskii plantations. Then, we explored deep soil water characteristics of different vegetation types and slope aspects and the variation tendencies of deep soil water at different recovery stages. The results showed that there were no significant differences in deep soil water content between sunny and shady slopes, and thus, slope aspect was not the key impact factor affecting deep soil water. Deep soil water content on R. pseudoacacia plantations and C. korshinskii plantations was lower than that on natural abandoned slopes; there were no significant differences in soil water content between the natural abandoned slopes and slope croplands. Soil desiccation did not exist on natural abandoned slopes; thus, natural vegetation restoration is an appropriate way to achieve a sustainable ecosystem with respect to deep soil water. In contrast, soil desiccation intensified until it was difficult for vegetation to obtain available water in the deep soil layer on the plantations; soil desiccation began to appear at the 11–20-year stage, and it became increasingly severe until the deep soil water was close to the wilting coefficient at the ≥30-year stage on R. pseudoacacia plantations. Deep soil water was rapidly consumed, and soil desiccation began to appear at the 1–10-year stage and then was close to the wilting coefficient in the later stages on C. korshinskii plantations. According to the results, the plantations needed to be managed in a timely manner to prevent or reduce soil desiccation.

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