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.

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.

Coupling model of ecohydrology and simulation of typical shrub ecosystems on the Loess Plateau

2020 ◽  
Author(s):  
Yu Zhang ◽  
Xiaoyan Li ◽  
Wei Li ◽  
Weiwei Fang ◽  
Fangzhong Shi
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Loess Plateau ◽  
Field Experiments ◽  
Annual Precipitation ◽  
The Loess Plateau ◽  
Rainfall Interception ◽  
Area Index ◽  
Caragana Korshinskii

&lt;p&gt;Shrub is the main vegetation type for vegetation restoration in the Loess Plateau, which plays an important role in the regional ecosystem restoration. Study on the relationships between vegetation and soil water of typical shrub ecosystems are significant for the restoration and reconstruction of ecosystems in the Loess Plateau. Three typical shrub (&lt;em&gt;Hippophae rhamnoides&lt;/em&gt; Linn., &lt;em&gt;Spiraea pubescens&lt;/em&gt; Turcz., and &lt;em&gt;Caragana korshinskii&lt;/em&gt; Kom.) ecosystems were chosen in the Loess Plateau. Field experiments were conducted to investigate the factors that influencing the processes of rainfall interception and root uptake of typical shrubs. S-Biome-BGC model was established based on the Biome-BGC model by developing the rainfall interception and soil water movement sub-models. The model was calibrated and verified using field data. The calibrated S-Biome-BGC model was used to simulate the characteristics of leaf area index (&lt;em&gt;LAI&lt;/em&gt;), net primary productivity (&lt;em&gt;NPP&lt;/em&gt;), soil water content and the interactions among them for the shrub ecosystems along the precipitation gradients in the Loess Plateau, respectively. The results showed that the predictions of the S-Biome-BGC model for soil water content and&lt;em&gt; LAI&lt;/em&gt; of typical shrub ecosystems in Loess Plateau were significantly more accurate than that of Biome-BGC model. The simulated &lt;em&gt;RMSE&lt;/em&gt; of soil water content decreased from 0.040~0.130 cm&lt;sup&gt;3&lt;/sup&gt; cm&lt;sup&gt;-3&lt;/sup&gt; to 0.026~0.035 cm&lt;sup&gt;3&lt;/sup&gt; cm&lt;sup&gt;-3&lt;/sup&gt;, and the simulated &lt;em&gt;RMSE&lt;/em&gt; of&lt;em&gt; LAI&lt;/em&gt; decreased from 0.37~0.70 m&lt;sup&gt;2&lt;/sup&gt; m&lt;sup&gt;-2&lt;/sup&gt; to 0.35~0.37 m&lt;sup&gt;2&lt;/sup&gt; m&lt;sup&gt;-2&lt;/sup&gt;. Therefore, the S-Biome-BGC model can reflect the interaction between plant growth and soil water content in the shrub ecosystems of the Loess Plateau. The S-Biome-BGC model simulation for &lt;em&gt;LAI&lt;/em&gt;,&lt;em&gt; NPP&lt;/em&gt; and soil water content of the three typical shrubs were significantly different along the precipitation gradients, and increased with annual precipitation together. However, different &lt;em&gt;LAI&lt;/em&gt;, &lt;em&gt;NPP&lt;/em&gt; and soil water correlations were found under different precipitation gradients.&lt;em&gt; LAI&lt;/em&gt; and&lt;em&gt; NPP&lt;/em&gt; have significant positive correlations with soil water content in the areas where the annual precipitation is above 460~500 mm that could afford the shrubs growth. The results of the study provide a re-vegetation threshold to guide future re-vegetation activities in the Loess Plateau.&lt;/p&gt;

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 Precipitation variability and soil water content in Pampean Flatlands (Argentina)

2008 ◽  
Vol 47 (4) ◽  
pp. 341-354
Author(s):  
J. Forte Lay ◽  
O. Scarpati ◽  
A. Capriolo
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Precipitation Variability ◽  
Annual Precipitation ◽  
Agricultural Activities ◽  
Water Supplies

The goal of this paper is to show the precipitation variability in pampean flatlands during the last decades and the con- sequential changes in soil water content. Two periods of 30 years each (1947-1976 and 1977-2006) were analyzed and an increase in annual precipitation all over the region was found in the last one. Areas with different increase in precipitation were located and these varied between 50 and 200 mm in annual precipitation. The bigger increase was found in the warm semester (October-March) in the center-western part of the region. One of the consequences of this was the increase in soil water supplies, which is very important for the development of agricultural activities.

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.

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 Forest decline caused by high soil water conditions in a permafrost region

2010 ◽  
Vol 14 (2) ◽  
pp. 301-307 ◽  
Author(s):  
H. Iwasaki ◽  
H. Saito ◽  
K. Kuwao ◽  
T. C. Maximov ◽  
S. Hasegawa
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Forest Recovery ◽  
Annual Precipitation ◽  
Line Transect ◽  
Permafrost Region ◽  
Taiga Forest ◽  
Water Conditions ◽  
Soil Water Conditions

Abstract. In the permafrost region near Yakutsk, eastern Siberia, Russia, annual precipitation (June–May) in 2005–2006 and 2006–2007 exceeded the 26-year (1982–2008) mean of 222±68 mm by 185 mm and 128 mm, respectively, whereas in 2007–2008 the excedent was only 48 mm, well within the range of variability. Yellowing and browning of larch (Larix cajanderi Mayr.) trees occurred in an undisturbed forest near Yakutsk in the 2007 summer growing season. Soil water content at a depth of 0.20 m was measured along a roughly 400 m long line transect running through areas of yellowing and browning larch trees (YBL) and of normal larch trees (NL). In the two years of supranormal precipitation, soil water content was very high compared to values recorded for the same area in previous studies. For both wet years, the mean degree of saturation (s) was significantly greater in YBL than NL areas, whereas the converse was the case for the gas diffusivity in soil. This implies that rather than mitigating water stress suffered during normal precipitation years, elevated soil water conditions adversely affected the growth of larch trees. Eastern Siberia's taiga forest extends widely into the permafrost region. Was such supranormal annual precipitation to extend for more than two years, as might be expected under impending global climate changes, forest recovery may not be expected and emission of greenhouse gas might continue in future.

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