The influence of annual precipitation, topography, and vegetative cover on soil moisture and summer drought in southern California

Oecologia ◽  
1983 ◽  
Vol 56 (2-3) ◽  
pp. 385-391 ◽  
Author(s):  
P. C. Miller ◽  
D. K. Poole
Keyword(s):  
Soil Moisture ◽  
Southern California ◽  
Annual Precipitation ◽  
Summer Drought ◽  
Vegetative Cover

scholarly journals Representation of Soil Moisture Feedbacks during Drought in NASA Unified WRF (NU-WRF)

2013 ◽  
Vol 14 (1) ◽  
pp. 360-367 ◽  
Author(s):  
Benjamin F. Zaitchik ◽  
Joseph A. Santanello ◽  
Sujay V. Kumar ◽  
Christa D. Peters-Lidard
Keyword(s):  
Soil Moisture ◽  
Great Plains ◽  
Climate Models ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Summer Drought ◽  
Dynamic Surface ◽  
Seasonal Drought ◽  
Weather Forecasts ◽  
Local Soil

Abstract Positive soil moisture–precipitation feedbacks can intensify heat and prolong drought under conditions of precipitation deficit. Adequate representation of these processes in regional climate models is, therefore, important for extended weather forecasts, seasonal drought analysis, and downscaled climate change projections. This paper presents the first application of the NASA Unified Weather Research and Forecasting Model (NU-WRF) to simulation of seasonal drought. Simulations of the 2006 southern Great Plains drought performed with and without soil moisture memory indicate that local soil moisture feedbacks had the potential to concentrate precipitation in wet areas relative to dry areas in summer drought months. Introduction of a simple dynamic surface albedo scheme that models albedo as a function of soil moisture intensified the simulated feedback pattern at local scale—dry, brighter areas received even less precipitation while wet, whereas darker areas received more—but did not significantly change the total amount of precipitation simulated across the drought-affected region. This soil-moisture-mediated albedo land–atmosphere coupling pathway is structurally excluded from standard versions of WRF.

scholarly journals Interactive Effects of Moss-Dominated Crusts andArtemisia ordosicaon Wind Erosion and Soil Moisture in Mu Us Sandland, China

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yongsheng Yang ◽  
Chongfeng Bu ◽  
Xingmin Mu ◽  
Hongbo Shao ◽  
Kankan Zhang
Keyword(s):  
Soil Moisture ◽  
Wind Erosion ◽  
Water Environment ◽  
Interactive Effects ◽  
Vegetative Cover ◽  
Artemisia Ordosica ◽  
Negative Effects ◽  
Rainwater Infiltration ◽  
Bare Sand ◽  
Soil Crusts

To better understand the effects of biological soil crusts (BSCs) on soil moisture and wind erosion and study the necessity and feasibility of disturbance of BSCs in the Mu Us sandland, the effects of four treatments, including moss-dominated crusts alone,Artemisia ordosicaalone, bare sand, andArtemisia ordosicacombined with moss-dominated crusts, on rainwater infiltration, soil moisture, and annual wind erosion were observed. The major results are as follows. (1) The development of moss-dominated crusts exacerbated soil moisture consumption and had negative effects on soil moisture in the Mu Us sandland. (2) Moss-dominated crusts significantly increased soil resistance to wind erosion, and when combined withArtemisia ordosica, this effect became more significant. The contribution of moss-dominated crusts underArtemisia ordosicawas significantly lower than that of moss-dominated crusts alone in sites where vegetative coverage > 50%. (3) Finally, an appropriate disturbance of moss-dominated crusts in the rainy season in sites with high vegetative coverage improved soil water environment and vegetation succession, but disturbance in sites with little or no vegetative cover should be prohibited to avoid the exacerbation of wind erosion.

scholarly journals Temperature and moisture dependence of daily growth of Scots pine (Pinus sylvestris L.) roots in Southern Finland

2019 ◽  
Vol 40 (2) ◽  
pp. 272-283
Author(s):  
Yiyang Ding ◽  
Pauliina Schiestl-Aalto ◽  
Heljä-Sisko Helmisaari ◽  
Naoki Makita ◽  
Kira Ryhti ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Pinus Sylvestris ◽  
Scots Pine ◽  
Growth Patterns ◽  
Root Production ◽  
Summer Drought ◽  
Daily Growth ◽  
Drought Effect ◽  
Fibrous Roots ◽  
Root Types

Abstract Scots pine (Pinus sylvestris L.) is one of the most important conifers in Northern Europe. In boreal forests, over one-third of net primary production is allocated to roots. Pioneer roots expand the horizontal and vertical root systems and transport nutrients and water from belowground to aboveground. Fibrous roots, often colonized by mycorrhiza, emerge from the pioneer roots and absorb water and nutrients from the soil. In this study, we installed three flatbed scanners to detect the daily growth of both pioneer and fibrous roots of Scots pine during the growing season of 2018, a year with an unexpected summer drought in Southern Finland. The growth rate of both types of roots had a positive relationship with temperature. However, the relations between root elongation rate and soil moisture differed significantly between scanners and between root types indicating spatial heterogeneity in soil moisture. The pioneer roots were more tolerant to severe environmental conditions than the fibrous roots. The pioneer roots initiated elongation earlier and ceased it later than the fibrous roots. Elongation ended when the temperature dropped below the threshold temperature of 4 °C for pioneer roots and 6 °C for fibrous roots. During the summer drought, the fibrous roots halted root surface area growth at the beginning of the drought, but there was no drought effect on the pioneer roots over the same period. To compare the timing of root production and the aboveground organs’ production, we used the CASSIA model, which estimates the aboveground tree carbon dynamics. In this study, root growth started and ceased later than growth of aboveground organs. Pioneer roots accounted for 87% of total root productivity. We suggest that future carbon allocation models should separate the roots by root types (pioneer and fibrous), as their growth patterns are different and they have different reactions to changes in the soil environment.

Rooting depth and plant water relations explain species distribution patterns within a sandplain landscape

2004 ◽  
Vol 31 (5) ◽  
pp. 423 ◽  
Author(s):  
Philip K. Groom
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Loss ◽  
Rooting Depth ◽  
Summer Drought ◽  
Tissue Water ◽  
Shrub Species ◽  
Water Deficits ◽  
Groundwater Levels ◽  
Water Potentials

Tree and shrub species of the Banksia woodlands on the sandplains of northern Swan Coastal Plain, Western Australia possess a range of strategies to avoid or tolerate soil water deficits during the annual summer drought. Shallow-rooted shrub species (< 1 m rooting depth) inhabit a range of locations in the landscape, from top of dune crests to wetland embankments. These are the most drought-tolerant of all sandplain species, surviving extremely low summer soil water potentials (< –7 MPa) and tissue water deficits by significantly reducing their transpirational water loss (< 0.2 mmol m–2 s–1). This is in contrast to the few shallow-rooted species restricted to low-lying or seasonally waterlogged areas which are reliant on subsurface soil moisture or groundwater to maintain their relatively high summer water use. Recent studies of water source usage of selected Banksia tree species have shown that these deep-rooted species access groundwater up to a maximum depth of 9 m depth during the summer months, or soil moisture at depth when groundwater was greater than maximum rooting depths, depending on the species. Medium- and deep-rooted (1–2 m and > 2 m, respectively) shrub species cope with the summer soil drying phase and related decrease in groundwater levels by conserving leaf water loss and incurring predawn water potentials between –1 and –4 MPa, enabling them to occur over a range of topographic positions within the sandplain landscape.

Pollen Response-Surface Estimates of Late-Quaternary Changes in the Moisture Balance of the Northeastern United States

1993 ◽  
Vol 40 (2) ◽  
pp. 213-227 ◽  
Author(s):  
Robert S. Webb ◽  
Katherine H. Anderson ◽  
Thompson Webb
Keyword(s):  
Soil Moisture ◽  
Water Level ◽  
Late Quaternary ◽  
Response Surfaces ◽  
Water Level Fluctuations ◽  
Annual Precipitation ◽  
Mean Annual Precipitation ◽  
Northeastern United States ◽  
Pollen Data ◽  
Moisture Balance

AbstractQuantitative estimates of late-Quaternary climate in the northeastern United States are reconstructed from fossil pollen data to evaluate changes in the regional moisture balance inferred from water-level fluctuations. We use environmental response surfaces to calibrate modern pollen data (for 17 different taxa) to an index of effective soil moisture and mean annual precipitation. We apply these response surfaces to fossil pollen data from 60 sites in the region to reconstruct changes in soil moisture and mean annual precipitation at 3000-yr intervals from 12,000 yr B.P. to present. The mapped reconstructions of soil moisture and mean annual precipitation illustrate how the regional moisture balance of the Northeast may have changed over the last 12,000 yr in response to changing climate. Reconstructions of annual precipitation show a gradual increase from 30% below modern values at 12,000 yr B.P. to near-modern values by 6000 yr B.P. and then remain relatively constant thereafter. Reconstructed changes in the index of effective soil moisture, however, show a pattern of near-modern values at 12,000, 6000, and 3000 yr B.P., with significantly lower values estimated for 9000 yr B.P., the time of maximum pine pollen abundances in the Northeast. This pattern of change is similar to the change in regional moisture balance inferred from stratigraphic records of water-level fluctuations. These results confirm previous interpretations, based on records of water-level fluctuations, that conditions in the Northeast were significantly drier during the early to middle Holocene than at other times during the last 12,000 yr.

COMPARISON OF LIGHTLY GRAZED AND UNGRAZED RANGE IN THE FESCUE GRASSLAND OF SOUTHWESTERN ALBERTA

1961 ◽  
Vol 41 (3) ◽  
pp. 615-622 ◽  
Author(s):  
Alexander Johnston
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Field Study ◽  
Water Intake ◽  
Soil Profile ◽  
Basal Area ◽  
The Other ◽  
Intake Rate ◽  
Vegetative Cover ◽  
Harmful Effects

The influence of grazing on the vegetative cover of fescue grassland in southwestern Alberta was assessed by studying two adjoining sites, one lightly grazed, the other ungrazed. Percentage basal area, yield, water-intake rate, soil temperature, soil moisture, and amount of root material were compared on a paired plot basis.The data showed that light grazing resulted in the development of a richer flora dominated by Danthonia parryi. Protection from grazing appeared to simplify the flora with a trend toward a cover consisting largely of Festuca scabrella. There was little evidence of difference in productivity between the two sites. Cooler and moister conditions prevailed in the upper 12 inches of the soil profile of the ungrazed site as a result of heavy accumulation of mulch. Considerably more root material to a depth of 54 inches was present on the lightly grazed site. The harmful effects of herbage removal, shown by clipping studies, were not apparent in the field study under a light rate of grazing.

Pentad Evolution of the 1988 Drought and 1993 Flood over the Great Plains: An NARR Perspective on the Atmospheric and Terrestrial Water Balance

2009 ◽  
Vol 22 (20) ◽  
pp. 5366-5384 ◽  
Author(s):  
Scott J. Weaver ◽  
Alfredo Ruiz-Barradas ◽  
Sumant Nigam
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Great Plains ◽  
Land Surface ◽  
Surface States ◽  
Moisture Flux ◽  
Summer Drought ◽  
Southern Plains ◽  
The North ◽  
Terrestrial Water

Abstract The evolution of the atmospheric and land surface states during extreme hydroclimate episodes over North America is investigated using the North American Regional Reanalysis (NARR), which additionally, and successfully, assimilates precipitation. The pentad-resolution portrayals of the atmospheric and terrestrial water balance over the U.S. Great Plains during the 1988 summer drought and the July 1993 floods are analyzed to provide insight into the operative mechanisms including regional circulation (e.g., the Great Plains low-level jet, or GPLLJ) and hydroclimate (e.g., precipitation, evaporation, soil moisture recharge, runoff). The submonthly (but supersynoptic time scale) fluctuations of the GPLLJ are found to be very influential, through related moisture transport and kinematic convergence (e.g., ∂υ/∂y), with the jet anomalies in the southern plains leading the northern precipitation and related moisture flux convergence, accounting for two-thirds of the dry and wet episode precipitation amplitude. The soil moisture influence on hydroclimate evolution is assessed to be marginal as evaporation anomalies are found to lag precipitation ones, a lead–lag not discernible at monthly resolution. The pentad analysis thus corroborates the authors’ earlier findings on the importance of transported moisture over local evaporation in Great Plains’ summer hydroclimate variability. The regional water budgets—atmospheric and terrestrial—are found to be substantially unbalanced, with the terrestrial imbalance being unacceptably large. Pentad analysis shows the atmospheric imbalance to arise from the sluggishness of the NARR evaporation, including its overestimation in wet periods. The larger terrestrial imbalance, on the other hand, has its origins in the striking unresponsiveness of the NARR’s runoff, which is underestimated in wet episodes. Finally, the influence of ENSO and North Atlantic Oscillation (NAO) variability on the GPLLJ is quantified during the wet episode, in view of the importance of moisture transports. It is shown that a significant portion (∼25%) of the GPLLJ anomaly (and downstream precipitation) is attributable to NAO and ENSO’s influence, and that this combined influence prolongs the wet episode beyond the period of the instigating GPLLJ.

Vegetation Control and Soil Moisture Depletion Related to Herbicide Treatments on Forest Plantations in Northeastern Oregon

2018 ◽  
Vol 32 (4) ◽  
pp. 461-474 ◽  
Author(s):  
Elizabeth Cole ◽  
Amanda Lindsay ◽  
Michael Newton ◽  
John D. Bailey
Keyword(s):  
Soil Moisture ◽  
First Year ◽  
Forest Plantations ◽  
Vegetative Cover ◽  
Tree Seedling ◽  
Vegetation Control ◽  
Herbicide Treatments ◽  
Inland Northwest ◽  
Comparable Control ◽  
Second Year

AbstractReforestation in the Inland Northwest, including northeastern Oregon, USA, is often limited by a dry climate and soil moisture availability during the summer months. Reduction of competing vegetative cover in forest plantations is a common method for retaining available soil moisture. Several spring and summer site preparation (applied prior to planting) herbicide treatments were evaluated to determine their efficacy in reducing competing cover, thus retaining soil moisture, on three sites in northeastern Oregon. Results varied by site, year, and season of application. In general, sulfometuron (0.14 kg ai ha–1 alone and in various mixtures), imazapyr (0.42 ae kg ha–1), and hexazinone (1.68 kg ai ha–1) resulted in 3 to 17% cover of forbs and grasses in the first-year when applied in spring. Sulfometuron+glyphosate (2.2 kg ha–1) consistently reduced grasses and forbs for the first year when applied in summer, but forbs recovered in the second year on two of three sites. Aminopyralid (0.12 kg ae ha–1)+sulfometuron applied in summer also led to comparable control of forb cover. In the second year after treatment, forb cover in treated plots was similar to levels in nontreated plots, and some species of forbs had increased relative to nontreated plots. Imazapyr (0.21 and 0.42 kg ha–1) at either rate, spring or summer 2007, or at lower rate (0.14 kg ha–1) with glyphosate in summer, provided the best control of shrubs, of which snowberry was the dominant species. Total vegetative cover was similar across all treatments seven and eight years after application, and differences in vegetation were related to site rather than treatment. In the first year after treatment, rates of soil moisture depletion in the 0- to 23-cm depth were correlated with vegetative cover, particularly late season soil moisture, suggesting increased water availability for tree seedling growth.

scholarly journals Role of Soil Moisture Feedback in the Development of Extreme Summer Drought and Flood in the United States

2016 ◽  
Vol 17 (8) ◽  
pp. 2191-2207 ◽  
Author(s):  
Roop Saini ◽  
Guiling Wang ◽  
Jeremy S. Pal
Keyword(s):  
United States ◽  
Soil Moisture ◽  
Large Scale ◽  
Climate Model ◽  
The United States ◽  
Summer Drought ◽  
Large Set ◽  
Drought And Flood ◽  
The Impact ◽  
Soil Moisture Feedback

Abstract This study tackles the contribution of soil moisture feedback to the development of extreme summer precipitation anomalies over the conterminous United States using a regional climate model. The model performs well in reproducing both the mean climate and extremes associated with drought and flood. A large set of experiments using the model are conducted that involve swapped initial soil moisture between flood and drought years using the 1988 and 2012 droughts and 1993 flood as examples. The starting time of these experiments includes 1 May (late spring) and 1 June (early summer). For all three years, the impact of 1 May soil moisture swapping is much weaker than the 1 June soil moisture swapping. In 1988 and 2012, replacing the 1 June soil moisture with that from 1993 reduces both the spatial extent and the severity of the simulated summer drought and heat. The impact is especially strong in 2012. In 1993, however, replacing the 1 June soil moisture with that from 1988 has little impact on precipitation. The contribution of soil moisture feedback to summer extremes is larger in 2012 than in 1988 and 1993. This may be because of the presence of strong anomalies in large-scale forcing in 1988 and 1993 that prohibit or favor precipitation, and the lack of such in 2012. This study demonstrates how the contribution of land–atmosphere feedback to the development of seasonal climate anomalies may vary from year to year and highlights its importance in the 2012 drought.

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