Soil water extraction by a mixed eucalypt forest during a drought period

Soil Research ◽  
1986 ◽  
Vol 24 (1) ◽  
pp. 25 ◽  
Author(s):  
T Talsma ◽  
EA Gardner
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Water Table ◽  
Unsaturated Flow ◽  
Growth Ring ◽  
Soil Water Potential ◽  
Water Extraction ◽  
Depth Interval ◽  
Summer Drought ◽  
Drought Period

Eucalypt trees growing on deep soils, with a water table at about 8 m depth, showed no apparent drought effects during the 1982-83 dry period in south-east Australia when gross precipitation was only 388 mm. At the end of the drought, soil water to 4 m depth was depleted to a soil water potential of -0.5 MPa and under these conditions unsaturated flow from the water table to the lower root zone was calculated to be 0.17 mm day-1. Water extraction over the depth interval from 0 to 6 m in the drought year was 533 mm, some 200 mm in excess of that used during a year of average rainfall. The contribution to tree water use from unsaturated flow from the water table was calculated to be small (15 mm) even in a drought year, and in most years water movement would be towards the water table to yield a deep drainage term estimated between 40 and 100 mm. Growth ring studies indicated that the lower water use, estimated at 2.6 mm day-1 during the spring-summer drought, did not affect the slowly growing E. radiata species, but reduced stem diameter growth of the faster growing E. dalrympleana and E. pauciflora species.

Response of four grain legumes to water stress in south-eastern Queensland. II.Plant growth and soil water extraction patterns

1982 ◽  
Vol 33 (3) ◽  
pp. 497 ◽  
Author(s):  
RJ Lawn
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Water Use ◽  
Developmental Plasticity ◽  
Water Extraction ◽  
Green Gram ◽  
Black Gram ◽  
Drought Period ◽  
Soil Water Extraction ◽  
Dehydration Avoidance

Growth and water use of soybean (Glycine max), black gram (Vigna mungo), green gram (V. radiata) and cowpea (V. unguiculata) in response to water stress were evaluated in the field at Dalby in southeast Queensland. Differing strategies of growth and water use which reflected the differential expression of dehydration avoidance and developmental plasticity in response to stress were identified among species. The primary difference between strategies related to differences in dehydration avoidance. Soil water extraction during the initial phases of drought was faster, and leaf area development and plant growth were relatively less affected, in soybean than in the Vigna spp. Where adequate soil water existed, these differences were sustained during the drought period but were reversed where soil water was limited. Soil water extraction by soybean occurred to greater depths, and to lower potentials, than in the Vigna spp. Developmental plasticity influenced growth pattern in the Vigna spp. to varying degrees. Drought periods invariably curtailed growth and hastened maturity in green gram and black gram, but rain prior to maturity induced renewed growth in black gram. Moderate stress curtailed growth and hastened maturity in cowpea, which also responded to late rains with renewed growth. Severe stress inhibited growth and delayed development in cowpea indefinitely.

scholarly journals Peat depth as a control on moss water availability during drought

2020 ◽  
Author(s):  
Paul Moore ◽  
Benjamin Didemus ◽  
Alexander Furukawa ◽  
James Waddington
Keyword(s):  
Climate Change ◽  
Water Content ◽  
Soil Water ◽  
Water Table ◽  
Summer Drought ◽  
Drought Period ◽  
Near Surface ◽  
Soil Water Tension ◽  
Water Tension

Peatlands are globally important long-term sinks of carbon, however there is concern that enhanced moss moisture stress due to climate change mediated drought will reduce moss productivity making these ecosystems vulnerable to carbon loss and associated long-term degradation. Peatlands are resilient to summer drought moss stress because of negative ecohydrological feedbacks that generally maintain a wet peat surface, but where feedbacks may be contingent on peat depth. We tested this ‘survival of the deepest’ hypothesis by examining water table position, near-surface moisture content, and soil water tension in peatlands that differ in size, peat depth, and catchment area during a summer drought. All shallow sites lost their WT (i.e. the groundwater well was dry) for considerable time during the drought period. Near-surface soil water tension increased dramatically at shallow sites following water table loss, increasing ~5–7.5× greater at shallow sites compared to deep sites. During a mid-summer drought intensive field survey we found that 60%–67% of plots at shallow sites exceeded a 100 mb tension threshold used to infer moss water stress. Unlike the shallow sites, tension typically did not exceed this 100 mb threshold at the deep sites. Using species dependent water content - chlorophyll fluorescence thresholds and relations between volumetric water content and water table depth, Monte Carlo simulations suggest that moss had nearly twice the likelihood of being stressed at shallow sites (0.38 ± 0.24) compared to deep sites (0.22 ± 0.18). This study provides evidence that mosses in shallow peatland may be particularly vulnerable to warmer and drier climates in the future, but where species composition may play an important role. We argue that a critical ‘threshold’ peat depth specific for different hydrogeological and hydroclimatic regions can be used to assess what peatlands are especially vulnerable to climate change mediated drought.

Water use by winter wheat as affected by soil management

1984 ◽  
Vol 103 (1) ◽  
pp. 189-199 ◽  
Author(s):  
M. J. Goss ◽  
K. R. Howse ◽  
Judith M. Vaughan-Williams ◽  
M. A. Ward ◽  
W. Jenkins
Keyword(s):  
Winter Wheat ◽  
Soil Water ◽  
Water Deficit ◽  
Water Use ◽  
Management Practices ◽  
Soil Management ◽  
Maximum Depth ◽  
Water Extraction ◽  
Soil Water Deficit ◽  
Potential Yield

SummaryIn each of the years from September 1977 to July 1982 winter wheat was grown on one or more of three clay soil sites (clay content 35–55%) in Oxfordshire where the climate is close to the average for the area of England growing winter cereals.The effects on crop water use of different soil management practices, including ploughing, direct drilling and subsoil drainage, are compared. Cultivation treatment had little effect on the maximum depth of water extraction, which on average in these clay soils was 1·54 m below the soil surface. Maximum soil water deficit was also little affected by cultivation; the maximum recorded value was 186±7·6 mm. Subsoil drainage increased the maximum depth of water extraction by approximately 15 cm and the maximum soil water deficit by about 17 mm.Generally soil management had little effect on either total water use by the crop which was found to be close to the potential evaporation estimated by the method of Penman, or water use efficiency which for these crops was about 52 kg/ha par mm water used.Results are discussed in relation to limitations to potential yield.

Temporal and spatial patterns of soil water extraction and drought resistance among genotypes of a perennial C4 grass

2013 ◽  
Vol 40 (4) ◽  
pp. 379 ◽  
Author(s):  
Yi Zhou ◽  
Christopher J. Lambrides ◽  
Matthew B. Roche ◽  
Alan Duff ◽  
Shu Fukai
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Drought Resistance ◽  
Field Experiments ◽  
Root Length Density ◽  
Water Extraction ◽  
Root Characteristics ◽  
Green Cover ◽  
C4 Grass ◽  
Soil Water Extraction

The objective of this study was to investigate patterns of soil water extraction and drought resistance among genotypes of bermudagrass (Cynodon spp.) a perennial C4 grass. Four wild Australian ecotypes (1–1, 25a1, 40–1, and 81–1) and four cultivars (CT2, Grand Prix, Legend, and Wintergreen) were examined in field experiments with rainfall excluded to monitor soil water extraction at 30–190 cm depths. In the study we defined drought resistance as the ability to maintain green canopy cover under drought. The most drought resistant genotypes (40–1 and 25a1) maintained more green cover (55–85% vs 5–10%) during water deficit and extracted more soil water (120–160 mm vs 77–107 mm) than drought sensitive genotypes, especially at depths from 50 to 110 cm, though all genotypes extracted water to 190 cm. The maintenance of green cover and higher soil water extraction were associated with higher stomatal conductance, photosynthetic rate and relative water content. For all genotypes, the pattern of water use as a percentage of total water use was similar across depth and time We propose the observed genetic variation was related to different root characteristics (root length density, hydraulic conductivity, root activity) although shoot sensitivity to drying soil cannot be ruled out.

Root Growth, Water Uptake and Canopy Development in Eucalyptus viminalis Seedlings

1994 ◽  
Vol 21 (1) ◽  
pp. 69 ◽  
Author(s):  
JG Phillips ◽  
SJ Riha
Keyword(s):  
Root Growth ◽  
Water Potential ◽  
Soil Water ◽  
Water Loss ◽  
Soil Water Potential ◽  
Water Extraction ◽  
Soil Conditions ◽  
Lower Section ◽  
Canopy Development ◽  
Eucalyptus Viminalis

A split-root experiment was conducted using Eucalyptus viminalis seedlings which were exposed to three watering regimes in order to investigate root growth and soil water extraction under conditions of a drying soil profile. Seedlings were grown in columns in which the soil was divided horizontally with a soft wax plate. Watering treatments were composed of (1) both upper and lower sections of the column well watered (W/W), (2) only the lower section well watered (D/W), and (3) water withheld completely from both upper and lower sections (D/D). Daily measurements included soil water potential (Ψs), column water loss and leaf elongation. Increase in above- and below-ground biomass was deter- mined from initial and final harvests after 25 days of treatment. Whole-column water loss and leaf extension were depressed as Ψs in the upper section of D/W and D/D decreased to -0.4 MPa over the first 8-10 days. However, water loss did not decrease significantly in the lower section of treatment D/W relative to the lower section of treatment W/W during this period. This indicated that water extraction by roots remaining in wet soil was not severely inhibited by the decrease in transpiration associated with the soil conditions in the upper profile. Root distribution at the end of the experiment indicated significant growth in the lower section of treatment D/W. There was evidence that hydraulic lifting of water between column sections may have occurred, as periodic increases in soil water potential of the unwatered upper section of D/W were observed.

Zero-tillage influence on canola, field pea and wheat in a dry subhumid region: Agronomic and physiological responses

1994 ◽  
Vol 74 (3) ◽  
pp. 411-420 ◽  
Author(s):  
Sylvia Borstlap ◽  
Martin H. Entz
Keyword(s):  
Grain Yield ◽  
Soil Water ◽  
Water Use ◽  
Field Pea ◽  
Water Extraction ◽  
Water Evaporation ◽  
Zero Tillage ◽  
Crop Species ◽  
Tillage System ◽  
Soil Water Extraction

Field trials were conducted over 4 site-years in southern Manitoba to compare the response of Katepwa wheat, Westar canola and Victoria field pea to zero tillage (ZT). The experimental design was a split plot with tillage system as the mainplot (ZT vs. conventional tillage (CT)) and crop species as the subplot. All crops received protection from insect, weed and disease pests. Tillage system had only a limited impact on crop dry matter accumulation or grain quality. Where differences were observed, crop performance was enhanced under ZT. Seasonal evapotranspiration (ET) was either reduced or unaffected by ZT, while ET efficiency (ETE: kg ha−1 mm−1 ET) was either increased or unchanged by the shift from CT to ZT. Higher ETE under ZT was attributed to less soil water evaporation. Significant tillage system × crop species (T × S) interactions for growth parameters, ET and ETE indicated that field pea often benefitted more than wheat or canola from ZT. A significant T × S interaction at one of the four sites indicated that water extraction between 30 and 90 cm was higher for pea and canola in the ZT compared with CT treatment, while soil water extraction by wheat was reduced under ZT. At a second site, lower ET for all three crops under ZT was attributed to reduced water use between 90 and 130 cm. Despite some effects of ZT on crop growth and water use, no significant tillage, T × S, or site × tillage interactions were observed for grain yield. It was concluded that under the conditions of this study (i.e. precipitation and temperature conditions close to the long-term average), Westar canola, Victoria field pea and Katepwa wheat were, for the most part, equally suited to ZT production. Key words: Soil water extraction, evapotranspiration efficiency, crop quality, grain yield, canopy development

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