COMPARISON OF MODELLED SOIL WATER RESERVES ON CANADIAN PRAIRIE SOILS WITH WATER-HOLDING CAPACITIES OF 280 AND 250 mm

1985 ◽  
Vol 65 (1) ◽  
pp. 219-223
Author(s):  
R. de JONG ◽  
W. K. SLY
Keyword(s):  
Soil Water ◽  
Perennial Crop ◽  
Canadian Prairie ◽  
Canadian Prairies ◽  
Prairie Soils ◽  
Available Water ◽  
Aridity Indices ◽  
Water Holding ◽  
Dough Stage

Based on soil water modelling results of 19 stations, averaged long-term soil water reserves on the Canadian Prairies were compared for two soils having available water-holding capacities of 280 and 250 mm. The soil water reserves of the 250-mm capacity soil were 6.5%, 8.7% and 6.2% less than those of the 280-mm capacity soil on 1 May after a fallow year, 30 June heading time and 1 May after a crop year, respectively. The aridity indices for wheat at the soft dough stage for the 250-mm capacity soil ranged from 4% less in the drier part of the Prairies to 7–9% more in the wetter regions as compared to the 280-mm capacity soil. Water deficits for a perennial crop grown on a 280-mm capacity soil could not be used to infer the deficits on a 250-mm capacity soil because of the model’s sensitivity to rainfall distribution with time. Key words: Soil water, modelling, available water-holding capacity

Quantification of Available Water Capacity Comparing Standard Methods and a Pedostructure Method on a Weakly Structured Soil

2019 ◽  
Vol 62 (2) ◽  
pp. 289-301
Author(s):  
Amjad T. Assi ◽  
Rabi H. Mohtar ◽  
Erik F. Braudeau ◽  
Cristine L. S. Morgan
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Field Capacity ◽  
Soil Aggregate ◽  
Pedotransfer Functions ◽  
Water Retention Curve ◽  
Aggregate Structure ◽  
Standard Methods ◽  
Available Water ◽  
Water Holding

Abstract. The purpose of this study was to evaluate the use of the pedostructure concept to determine the soil available water capacity, specifically the field capacity (FC). Pedostructure describes the soil aggregate structure and its thermodynamic interaction with water. Specifically, this work compared the calculation of soil water-holding properties based on the pedostructure concept with other standard methods for determining FC and permanent wilting point (PWP). The standard methods evaluated were the FAO texture estimate (FAO method), the Saxton-Rawls pedotransfer functions (PTFs method), and the water content at predefined soil suction (330 and 15,000 hPa) as measured with a pressure plate apparatus (PP method). Additionally, two pedostructure methods were assessed: the thermodynamic water retention curve (TWRC method) and the thermodynamic pedostructure (TPC method). Undisturbed loamy fine sand soil from a field in Millican, Texas, was analyzed at both the Ap and E horizons. The results showed that the estimated water content at FC and PWP for the three standard methods and for the TWRC method were in relative agreement. However, the TPC method used characteristic transition points in the modeled contents of different water pools in the soil aggregate and was higher for the Ap horizon, but in agreement with the other methods for the E horizon. For example, for the Ap horizon of the soil analyzed in this study, the FC estimated with the standard and TWRC methods ranged from 0.073 to 0.150 m3H2O m-3soil, while the TPC method estimate was 0.221 m3H2O m-3soil. Overall, the different methods showed good agreement in estimating the available water; however, the results also showed some variations in these estimates. It is clear that the TPC method has advantages over the other methods in considering the soil aggregate structure and modeling the soil water content within the aggregate structure. The thermodynamic nature of the TPC method enabled the use of both the soil shrinkage curve and the water retention curve in a weakly structured soil. It is expected that the TPC method would provide more comprehensive advances in understanding the soil water-holding properties of structured soils with higher clay contents. Keywords: Available water, Field capacity, Pedostructure, Pedotransfer functions, Permanent wilting point.

LONG-TERM SOIL MOISTURE STATUS IN SOUTHERN ALBERTA

1990 ◽  
Vol 70 (2) ◽  
pp. 125-136 ◽  
Author(s):  
C. CHANG ◽  
T. G. SOMMERFELDT ◽  
T. ENTZ ◽  
D. R. STALKER
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Continuous Cropping ◽  
Available Water ◽  
Southern Alberta ◽  
Available Soil Moisture ◽  
Fallow Field ◽  
Water Recharge ◽  
Soil Water Recharge

Nineteen years of soil moisture content data at Lethbridge and two locations near Turin (Turin 1 and Turin 2) in southern Alberta were examined to evaluate the efficiency of follow for conserving moisture, and to calculate the long-term mean amount of water recharge during growing and nongrowing seasons under a fallow-cereal, 2-yr rotation and a continuous cropping system. Soil samples were taken annually from 1969 to 1987 to a depth of 120 cm in 30-cm intervals in the spring (early May) and fall (late September). A method for testing differences of means between nonstandard data using localized uncertainty associated with sliding polynomial smoothing was used to test for differences in the soil moisture contents due to cultural practices. The available soil moisture content of the soil to 120-cm depth was at least 50% of available water-holding capacity (AWHC) of the profile for the fallow treatment at Lethbridge and Turin 2, and, except in some years, at Turin 1. At seeding time, there was an average of 69 mm more available water (AW) in the fallow field than in the continuous cropping field at Lethbridge and 30, 35 and 27 mm more AW in the fallow field than in the fresh stubble field of a fallow-cereal, 2-yr rotation for Lethbridge, Turin 1 and Turin 2, respectively. The overall mean precipitation conserved as soil moisture for the fallow-cereal rotation practice was 23, 29 and 23% for Lethbridge, Turin 1 and Turin 2, respectively. The significantly higher soil water content at the 90- to 120-cm depth for the fallow field than for other fields during various periods of time indicates that the soil water recharge from precipitation might be deeper in the fallow field than in continuous cropping and fresh stubble of fallow-cereal rotation fields. The deeper soil water recharge could increase the available soil moisture for crop production and it could also contribute to ground water recharge. Key words: Soil water, available water content, continuous cropping, summerfallow

AVAILABLE WATER-HOLDING CAPACITY MAPS OF ALBERTA, SASKATCHEWAN AND MANITOBA

1988 ◽  
Vol 68 (1) ◽  
pp. 157-163 ◽  
Author(s):  
R. DE JONG ◽  
J. A. SHIELDS
Keyword(s):  
Key Words ◽  
Soil Water ◽  
Water Holding Capacity ◽  
Crop Modelling ◽  
Available Water ◽  
Soil Landscape ◽  
Water Holding

Available water-holding capacity (AWC) maps of Alberta, Saskatchewan and Manitoba were derived from Soil Landscape maps (1:1 million scale) by substituting AWC classes for soil textural classes. The maps provide information required for the geographical interpretation of soil water and crop modelling analyses. Key words: Available water-holding capacity, maps, texture

ESTIMATED SOIL WATER RESERVES APPLICABLE TO A WHEAT-FALLOW ROTATION FOR GENERALIZED SOIL AREAS MAPPED IN SOUTHERN SASKATCHEWAN

1984 ◽  
Vol 64 (4) ◽  
pp. 667-680 ◽  
Author(s):  
R. DE JONG ◽  
J. A. SHIELDS ◽  
W. K. SLY
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Holding Capacity ◽  
Climatic Data ◽  
Moisture Budget ◽  
Model Soil ◽  
Available Water ◽  
Soil Zone ◽  
Water Holding ◽  
Soil Moisture Budget

Long-term mean soil water reserves for a spring wheat-fallow rotation in the southern half of Saskatchewan were calculated using the Versatile Soil Moisture Budget. Four different available water-holding capacity classes and climatic data from 53 stations were used as input to the model. Soil water reserve data for the following times, seeding on 1 May in the crop year, at heading on 30 June, and on 1 May in the fallow year, were mapped. These were then combined with an available water-holding capacity map to portray in a single map the combined droughtiness due to climatic and soil attributes. Estimated soil water reserves compared well with measured data from one location in the Brown soil zone. The temporal and spatial changes in water reserves are discussed and related to summerfallowing. The maps provide information for use in making potential grain yield estimates. Key words: Soil water, wheat-fallow rotation, generalized soil areas, Saskatchewan, Versatile soil moisture budget

The Available-Water Capacity of Barbados Soils

1969 ◽  
Vol 5 (3) ◽  
pp. 167-182 ◽  
Author(s):  
J. C. Hudson
Keyword(s):  
Soil Water ◽  
Agricultural Soils ◽  
Field Capacity ◽  
Soil Water Deficit ◽  
Water Capacity ◽  
Available Water ◽  
Montmorillonite Clays ◽  
Available Water Capacity ◽  
Water Holding ◽  
Large Soil

SummaryLarge soil monoliths, extracted undisturbed in 44-gallon oil drums, have been used to assess the available-water capacity, and the relation between the growth of sugarcane and soil water deficit for agricultural soils in Barbados. Constancy of field capacity was studied and the effect of cultivation on the storage of available soil water. Deep montmorillonite clays and oceanic soils had storage capacities greater than 20 cm. of water in an 80 cm. profile, whereas sandy or stony montmorillonite clays and most soils developed from kaolinite clays had capacities less than 11 cm. Cultivation significantly increased the water holding capacity of soils but this was rarely as great as for fabricated composts and the water was never so freely available. The data have been used in decisions about cultivation and irrigation, and as the basis for an ecological grouping of sugar estates according to their probable water balance.

Grazing impacts on soil water in mixed prairie and fescue grassland ecosystems of Alberta

1991 ◽  
Vol 71 (3) ◽  
pp. 313-325 ◽  
Author(s):  
M. A. Naeth ◽  
D. S. Chanasyk ◽  
R. L. Rothwell ◽  
A. W. Bailey
Keyword(s):  
Soil Water ◽  
Soil Surface ◽  
Canadian Prairies ◽  
Grazing Impacts ◽  
Growing Seasons ◽  
Grassland Ecosystems ◽  
Water Recharge ◽  
Grazing Intensities ◽  
Mixed Prairie

Reduced soil water under grazing is generally attributed to reduced infiltration as livestock trampling compacts the soil surface. Grazing can also have the opposite effect on soil water through reduced evapotranspiration when vegetation is removed. On the Canadian Prairies, grazing impacts on soil water have been assessed in short-term studies but impacts of long-term grazing have not been documented. In this study, impacts of long-term grazing on soil water were assessed in mixed prairie, parkland fescue grassland, and foothills fescue grassland ecosystems of southern and central Alberta. Grazing regimes were of light to very heavy intensities, grazed early, late, and continuously during the growing season. Soil water was measured with a neutron probe to a depth of 1 m from April through October over three growing seasons. Normal patterns of soil water recharge in autumn and spring and soil water depletion in summer due to evapotranspiration were not altered by grazing. Fluctuations in soil water were most pronounced in the uppermost 30 cm but still evident in the 30- to 50-cm and 50- to 80-cm depth intervals. Heavy intensity and/or early season grazing had a greater impact on soil water than light intensity and/or late season grazing. Season of grazing affected soil water more under light than heavy grazing intensities. On most sampling dates, soil water in grazed treatments was lower than in the ungrazed control, particularly in the 30- to 50-cm and 50- to 80-cm depth intervals. Differences between the control and grazed treatments were least pronounced during the summer months with evapotranspiration depleting soil water reserves in all treatments. Key words: Soil water, grazing, rangelands, water uptake

ESTIMATED LONG-TERM SOIL MOISTURE VARIABILITY ON THE CANADIAN PRAIRIES

1988 ◽  
Vol 68 (2) ◽  
pp. 307-321 ◽  
Author(s):  
R. DE JONG ◽  
A. BOOTSMA
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Production Systems ◽  
Moisture Budget ◽  
Canadian Prairies ◽  
Seeding Date ◽  
Water Contents ◽  
Soil Moisture Budget ◽  
Soil Water Contents

Soil water contents under wheat production systems on the Canadian prairies were estimated using the Versatile Soil Moisture Budget, which was modified to include an estimated seeding date and a biometeorological time scale. Large year-to-year variability required the use of long term (60 yr) data to describe seasonal and probable occurrences of soil water contents for 27 stations. Regression and correlation analyses were used to simplify presentation of the data and to display their spatial distribution. On average, summerfallowing was most effective in conserving water in areas with intermediate spring soil water contents and on soils with a higher available water-holding capacity (AWC). In abnormally dry years (i.e., 10% probability) summerfallowing conserved more water in the wetter areas while increasing the AWCs had the greatest effect on conserved water in the intermediate areas. Soil water contents at heading were greater under wheat-fallow rotation compared to continuous wheat and increased with increasing AWCs. Water contents of less than 50% of AWC at heading occurred with a probability of 80% or higher in most areas, indicating some stress is experienced in most years. Summerfallowing lowered the probability only slightly on soils with a low AWC, but by 10–20% on the higher AWC soils. The probability of extreme water stress at heading (i.e. water contents ≤ 10% of AWC) ranged from 0% in the wettest areas to 40–60% in the driest climatic area. Key words: Soil water content, versatile soil moisture budget, summer fallowing, zonation, wheat (spring), seeding date

Short-term effects of tillage of long-term no-till on nitrous oxide emissions from two contrasting Canadian prairie soils

2020 ◽  
Vol 100 (4) ◽  
pp. 453-462
Author(s):  
B.M.R. Shahidi ◽  
M. Dyck ◽  
S.S. Malhi ◽  
D. Puurveen
Keyword(s):  
Nitrous Oxide ◽  
Growing Season ◽  
N Fertilizer ◽  
Nitrous Oxide Emissions ◽  
Soil N ◽  
Canadian Prairie ◽  
Prairie Soils ◽  
No Till ◽  
Gray Luvisol

The reduction in net CO2 emissions from increased carbon sequestration in soil and slower decomposition of soil organic matter under most long-term no-till (NT) situations can potentially be offset by a concomitant increase in nitrous oxide (N2O) emissions after tillage reversal on long-term NT soils. The objective of this work was to quantify N2O emissions after tillage reversal on two contrasting western Canadian Prairie soils managed under long-term (∼30 yr) NT. We measured one growing season (2010) of soil N2O emissions on a Black Chernozem and Gray Luvisol at Ellerslie and Breton, AB, respectively, following 30 yr of NT and N fertilizer application at two rates (0 and 100 kg N ha−1) subjected to tillage reversal and no disturbance (i.e., continuing NT). Tillage reversal after long-term NT was associated with higher N2O emissions in both soils but was significant only in the Gray Luvisol with 0 kg N ha−1. Long-term N fertilizer applications of 100 kg N ha−1 were associated with higher growing season soil N2O emissions and higher levels of soil N (i.e., a positive, long-term soil N balance) at both sites. Regardless of tillage, the difference in growing season nitrous oxide emissions from the 0 and 100 kg N ha−1 plots on the Gray Luvisol were much greater than the Black Chernozem. A modest increase in N2O emissions upon tillage reversal on a long-term NT soils could translate to a significant increase to agricultural greenhouse gas inventories in the event of large-scale tillage reversal on agricultural land in western Canada.

THE SULPHUR STATUS OF EASTERN CANADIAN PRAIRIE SOILS: THE RELATIONSHIP OF SULPHUR, NITROGEN AND ORGANIC CARBON

1985 ◽  
Vol 65 (1) ◽  
pp. 179-186 ◽  
Author(s):  
L. D. BAILEY
Keyword(s):  
Sandy Loam ◽  
C:N Ratio ◽  
High Potential ◽  
Canadian Prairie ◽  
Canadian Prairies ◽  
Total N ◽  
Organic C ◽  
Prairie Soils ◽  
Relationship Of ◽  
The Relationship

Surface and subsurface samples of 17 of the most agriculturally important soils of the eastern Canadian prairies were analyzed for total S, sulphate S, total N and organic C. The soils varied in texture from sandy loam to clay loam. Fifteen of the soils were of the Chernozemic order, one was Brunisolic and the other Luvisolic. The subgroups included were Orthic Blacks, Gleyed Rego Blacks, Orthic Dark Greys, Eluviated Eutric Brunisol and Orthic Luvisol. The total S of the soils decreased with depth and was significantly correlated with total N and with organic C. The sulphate sulphur extracted with 0.1 M CaCl2 accounted for an average of 2.6% of the total S in each of the three soil depths analyzed. The calculated N:S and C:N ratios averaged 8.3 and 1.25 (0–15 cm), 7.2 and 14.1 (15–30 cm), and 6.5 and 11.0 (30–60 cm), respectively. The N:S ratios, and to limited extent the C:N ratios, were used to describe the sulphur status of the soils. Soil with N:S and C:N ratios 6.0 and 12.5 (0–15 cm), 5.2 and 13.5 (15–30 cm), 4.7 and 11.4 (30–60 cm), respectively, could have a high potential to supply sulphate S to plants and may not be deficient in plant-available S. Soils with N:S and C:N ratios of 8.7 and 13.5 (0–15 cm), 7.2 and 14.7 (15–30), 6.3 and 11.2 cm (30–60 cm), respectively, may be deficient in sulphur for some crops. However, they may have a high potential to convert total S to sulphate S. Soils with N:S and C:N ratio of 12.4 and 11.2 (0–15 cm), 11.1 and 13.0 (15–30), 10.2 and 9.9 (30–60 cm), respectively, may be deficient in plant-available S and could have a low potential for conversion of total S to sulphate S. Key words: Sulphur status of soils; potential available sulphur

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