Use of tree and shrub belts to control leakage in three dryland cropping environments

2002 ◽  
Vol 53 (5) ◽  
pp. 571 ◽  
Author(s):  
A. Knight ◽  
K. Blott ◽  
M. Portelli ◽  
C. Hignett
Keyword(s):  
Cropping Systems ◽  
Water Storage ◽  
Farming Systems ◽  
Soil Water Storage ◽  
Water Storage Capacity ◽  
Alley Farming ◽  
Episodic Event ◽  
Eastern Australia ◽  
Recharge Rates ◽  
Deep Profile

The water extraction of deep-rooted perennial trees and shrub belts integrated with annual cropping/grazing systems was studied at 3 sites in the 300–450 mm rainfall zone of the Murray–Darling Basin of south-eastern Australia. Within 4 years of planting alley farming systems on cropland, the soil directly below and near the belts had dried the deep profile. Between 82 and 261 mm of extra soil water storage capacity was created in the 2.5 to 5.5–6 m profile. At Palamana (the only site monitored to greater depth), living roots were found 16 m below the surface. The cumulative water content of the soil to 12 m under the belts was 600 mm less than of soil cores extracted from nearby cropland. This water storage difference created under the belts is greater than the largest episodic event likely in this region and it is therefore unlikely that leakage will occur directly under or within a few metres of the belts. The early growth of the belts was rapid and the leaf area of the belts far exceeded that of remnant mallee eucalypt vegetation. The belts used water that had accumulated deep in the profile below the annual cropping systems they replaced. However, the belts only used water from below or within a few metres from the edge with the adjacent cropland. As suggested by RJ Harper et al. (2000), a much greater amount of potential recharge could be controlled if deep-rooted perennials were planted more closely across the landscape (compared with widely spaced belts). However, although the belts may be beneficial for the catchment water balance, they would be commercially unacceptable to farmers. In practice, farmers put the belts usually no less than 50–70 m apart so that less cropland is displaced and there is less belt/crop competition. In such cases alley farming only controls a small percentage of the total leakage, similar to the amount of crop yield lost by displacement and competition. It would be better to use a full coverage of perennials on soils where annual systems are the leakiest, rather than belts across all of the landscape, some of which may not be very leaky and could be highly profitable for annual cropping. Leakage could be controlled under cropland in a few years by growing easy to establish perennial species to retrieve moisture deep in the profile. At Pallamana the belts utilised 600 mm of accumulated leakage from deep in the profile in less than 4 years. Based on the average annual recharge rates under annual cropping (11–35 mm) the land could be cropped again for between 17 and 55 years before that leakage accumulated again.

Predicting the impact of perennial phases on average leakage from farming systems in south-western Australia

2006 ◽  
Vol 57 (3) ◽  
pp. 269 ◽  
Author(s):  
P. R. Ward
Keyword(s):  
Water Storage ◽  
Farming Systems ◽  
Soil Types ◽  
Buffer Size ◽  
Soil Water Storage ◽  
Annual Rainfall ◽  
Water Storage Capacity ◽  
Modelling Studies ◽  
The Impact

Rising watertables and dryland salinity in southern Australia are due to excess groundwater recharge after the replacement of native vegetation by annual crops and pastures. The inclusion of perennial plants into agricultural systems has been proposed as a possible method of recharge reduction, through the creation of a buffer (extra water storage capacity generated by the perennial in comparison with an annual crop or pasture). However, the role of perennial phases under conditions of highly episodic leakage is not well understood. In this paper, a simple Leakage/Buffer Model (LeBuM) was developed to determine the effect of perennial phases on long-term average annual leakage, incorporating episodic events. Mechanistic modelling studies on contrasting soil types were used to demonstrate that leakage for any given May–December period was directly related to soil water storage at 1 May. From this finding, it follows that leakage from a phase rotation can be calculated if the size of the buffer, and the leakage quantity in the absence of a buffer, are known for each stage of the rotation. LeBuM uses a long-term sequence of leakage values in the absence of a buffer as input, and the maximum buffer size, its rate of development, and the length of perennial and annual phases are specified as parameters. LeBuM was applied to leakage data modelled for 5 contrasting soil types over 100 years at 24 sites in the Western Australian wheatbelt. Phase rotations on duplex, waterlogging duplex, or loamy sand soils reduced leakage by >90% for regions with <380 mm annual rainfall, but were less effective in wetter regions and on deep sands or acid loamy sands. Nevertheless, phase rotations if adopted widely could delay the onset of salinity by as much as several decades.

Water use, competition, and crop production in low rainfall, alley farming systems of south-eastern Australia

2003 ◽  
Vol 54 (8) ◽  
pp. 751 ◽  
Author(s):  
Murray Unkovich ◽  
Kerrin Blott ◽  
Alex Knight ◽  
Ivan Mock ◽  
Abdur Rab ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Crop Yield ◽  
Farming Systems ◽  
Alley Farming ◽  
Annual Crop ◽  
South Eastern ◽  
Annual Crops ◽  
Eastern Australia ◽  
Perennial Shrubs

Annual crops were grown in alleys between belts of perennial shrubs or trees over 3–4 years at 3 sites across low rainfall (<450 mm) south-eastern Australia. At the two lower rainfall sites (Pallamana and Walpeup), crop grain yields within 2–5 m of shrub belts declined significantly with time, with a reduction equivalent to 45% over 9 m in the final year of cropping. At the third, wetter site (Bridgewater), the reduction in crop grain yields adjacent to tree belts was not significant until the final year of the study (12% over 11 m) when the tree growth rates had increased. The reductions in crop yield were associated with increased competition for water between the shrub or tree belts and the crops once the soil profile immediately below the perennials had dried. At all 3 sites during the establishment year, estimates of water use under the woody perennials were less than under annual crops, but after this, trends in estimates of water use of alley farming systems varied between sites. At Pallamana the perennial shrubs used a large amount of stored soil water in the second summer after establishment, and subsequently were predominantly dependent on rainfall plus what they could scavenge from beneath the adjacent crop. After the establishment year at the Walpeup site, water use under the perennial shrubs was initially 67 mm greater than under the annual crop, declining to be only 24 mm greater in the final year. Under the trees at Bridgewater, water use consistently increased to be 243 mm greater than under the adjacent annual crop by the final year. Although the shrub belts used more water than adjacent crop systems at Walpeup and Pallamana, this was mostly due to the use of stored soil water, and since the belts occupied only 7–18% of the land area, increases in total water use of these alley farming systems compared with conventional crop monocultures were quite small, and in terms of the extent of recharge control this was less than the area of crop yield loss. At the wetter, Bridgewater site, alley farming appeared to be using an increasing amount of water compared with conventional annual cropping systems. Overall, the data support previous work that indicates that in lower rainfall environments (<350 mm), alley farming is likely to be dogged by competition for water between crops and perennials.

Using active fractions of soil organic matter as indicators of the sustainability of Ferrosol farming systems

Soil Research ◽  
1999 ◽  
Vol 37 (2) ◽  
pp. 279 ◽  
Author(s):  
M. J. Bell ◽  
P. W. Moody ◽  
S. A. Yo ◽  
R. D. Connolly
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Management Practices ◽  
Cropping Systems ◽  
Cropping System ◽  
Farming Systems ◽  
Total Carbon ◽  
Critical Concentrations ◽  
Aggregate Breakdown ◽  
Eastern Australia

Chemical and physical degradation of Red Ferrosols in eastern Australia is a major issue necessitating the development of more sustainable cropping systems. This paper derives critical concentrations of the active (permanganate-oxidisable) fraction of soil organic matter (C1) which maximise soil water recharge and minimise the likelihood of surface runoff in these soils. Ferrosol soils were collected from commercial properties in both north and south Queensland, while additional data were made available from a similar collection of Tasmanian Ferrosols. Sites represented a range of management histories, from grazed and ungrazed grass pastures to continuously cropped soil under various tillage systems. The concentration of both total carbon (C) and C1 varied among regions and farming systems. C1 was the primary factor controlling aggregate breakdown, measured by the percentage of aggregates <0·125 mm (P125) in the surface crust after simulated rainfall. The rates of change in P125 per unit change in C1 were not significantly different (P < 0·05) for soils from the different localities. However, soils from the coastal Burnett (south-east Queensland) always produced lower P125 (i.e. less aggregate breakdown) than did soils from the inland Burnett and north Queensland locations given the same concentration of C1. This difference was not associated with a particular land use. The ‘critical’ concentrations of C1 for each region were taken as the C1 concentrations that would allow an infiltration rate greater than or equal to the intensity of a 1 in 1 or 1 in 10 year frequency rainfall event of 30 min duration. This analysis also provided an indication of the risk associated with the concentrations of C1 currently characterising each farming system in each rainfall environment. None of the conventionally tilled Queensland Ferrosols contained sufficient C1 to cope with rainfall events expected to occur with a 1 in 10 frequency, while in many situations the C1 concentration was sufficiently low that runoff events would be expected on an annual basis. Our data suggest that management practices designed both to maximise C inputs and to maintain a high proportion of active C should be seen as essential steps towards developing a more sustainable cropping system.

Soil Water Storage in Dryland Cropping Systems: The Significance of Cropping Intensification

1998 ◽  
Vol 62 (4) ◽  
pp. 984-991 ◽  
Author(s):  
H. J. Farahani ◽  
G. A. Peterson ◽  
D. G. Westfall ◽  
L. A. Sherrod ◽  
L. R. Ahuja
Keyword(s):  
Soil Water ◽  
Cropping Systems ◽  
Water Storage ◽  
Soil Water Storage

scholarly journals A new probability density function for spatial distribution of soil water storage capacity leads to SCS curve number method

2018 ◽  
Author(s):  
Dingbao Wang
Keyword(s):  
Distribution Function ◽  
Storage Capacity ◽  
Water Storage ◽  
Soil Water Storage ◽  
Water Storage Capacity ◽  
Soil Storage ◽  
Soil Water Storage Capacity ◽  
Soil Wetting ◽  
Scs Cn ◽  
New Distribution

Abstract. Following the Budyko framework, soil wetting ratio (the ratio between soil wetting and precipitation) as a function of soil storage index (the ratio between soil wetting capacity and precipitation) is derived from the SCS-CN method and the VIC type of model. For the SCS-CN method, soil wetting ratio approaches one when soil storage index approaches infinity, due to the limitation of the SCS-CN method in which the initial soil moisture condition is not explicitly represented. However, for the VIC type of model, soil wetting ratio equals soil storage index when soil storage index is lower than a certain value, due to the finite upper bound of the power distribution function of storage capacity. In this paper, a new distribution function, supported on a semi-infinite interval x &amp;in; [0, ∞), is proposed for describing the spatial distribution of storage capacity. From this new distribution function, an equation is derived for the relationship between soil wetting ratio and storage index. In the derived equation, soil wetting ratio approaches zero as storage index approaches zero; when storage index tends to infinity, soil wetting ratio approaches a certain value (&amp;leq; 1) depending on the initial storage. Moreover, the derived equation leads to the exact SCS-CN method when initial water storage is zero. Therefore, the new distribution function for soil water storage capacity explains the SCS-CN method as a saturation excess runoff model and unifies the surface runoff modeling of SCS-CN method and VIC type of model.

scholarly journals Diagnosis toward predicting mean annual runoff in ungauged basins

2021 ◽  
Vol 25 (2) ◽  
pp. 945-956
Author(s):  
Yuan Gao ◽  
Lili Yao ◽  
Ni-Bin Chang ◽  
Dingbao Wang
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Storage Capacity ◽  
Water Storage ◽  
Annual Runoff ◽  
Balance Model ◽  
Soil Water Storage ◽  
Ungauged Basins ◽  
Water Storage Capacity ◽  
Soil Water Storage Capacity

Abstract. Prediction of mean annual runoff is of great interest but still poses a challenge in ungauged basins. The present work diagnoses the prediction in mean annual runoff affected by the uncertainty in estimated distribution of soil water storage capacity. Based on a distribution function, a water balance model for estimating mean annual runoff is developed, in which the effects of climate variability and the distribution of soil water storage capacity are explicitly represented. As such, the two parameters in the model have explicit physical meanings, and relationships between the parameters and controlling factors on mean annual runoff are established. The estimated parameters from the existing data of watershed characteristics are applied to 35 watersheds. The results showed that the model could capture 88.2 % of the actual mean annual runoff on average across the study watersheds, indicating that the proposed new water balance model is promising for estimating mean annual runoff in ungauged watersheds. The underestimation of mean annual runoff is mainly caused by the underestimation of the area percentage of low soil water storage capacity due to neglecting the effect of land surface and bedrock topography. Higher spatial variability of soil water storage capacity estimated through the height above the nearest drainage (HAND) and topographic wetness index (TWI) indicated that topography plays a crucial role in determining the actual soil water storage capacity. The performance of mean annual runoff prediction in ungauged basins can be improved by employing better estimation of soil water storage capacity including the effects of soil, topography, and bedrock. It leads to better diagnosis of the data requirement for predicting mean annual runoff in ungauged basins based on a newly developed process-based model finally.

scholarly journals A stochastic approach for the description of the water balance dynamics in a river basin

2008 ◽  
Vol 12 (5) ◽  
pp. 1189-1200 ◽  
Author(s):  
S. Manfreda ◽  
M. Fiorentino
Keyword(s):  
Water Balance ◽  
Probability Density ◽  
Soil Water ◽  
Storage Capacity ◽  
Water Storage ◽  
Soil Water Balance ◽  
Soil Water Storage ◽  
Water Storage Capacity ◽  
Soil Water Storage Capacity ◽  
Balance Dynamics

Abstract. The present paper introduces an analytical approach for the description of the soil water balance dynamics over a schematic river basin. The model is based on a stochastic differential equation where the rainfall forcing is interpreted as an additive noise in the soil water balance. This equation can be solved assuming known the spatial distribution of the soil moisture over the basin transforming the two-dimensional problem in space in a one dimensional one. This assumption is particularly true in the case of humid and semihumid environments, where spatial redistribution becomes dominant producing a well defined soil moisture pattern. The model allowed to derive the probability density function of the saturated portion of a basin and of its relative saturation. This theory is based on the assumption that the soil water storage capacity varies across the basin following a parabolic distribution and the basin has homogeneous soil texture and vegetation cover. The methodology outlined the role played by the soil water storage capacity distribution of the basin on soil water balance. In particular, the resulting probability density functions of the relative basin saturation were found to be strongly controlled by the maximum water storage capacity of the basin, while the probability density functions of the relative saturated portion of the basin are strongly influenced by the spatial heterogeneity of the soil water storage capacity. Moreover, the saturated areas reach their maximum variability when the mean rainfall rate is almost equal to the soil water loss coefficient given by the sum of the maximum rate of evapotranspiration and leakage loss in the soil water balance. The model was tested using the results of a continuous numerical simulation performed with a semi-distributed model in order to validate the proposed theoretical distributions.

Available water storage in a range of soils in north-eastern Queensland

1971 ◽  
Vol 11 (50) ◽  
pp. 343 ◽  
Author(s):  
RL McCown
Keyword(s):  
Soil Water ◽  
Storage Capacity ◽  
Water Storage ◽  
Total Porosity ◽  
Water Entry ◽  
Water Storage Capacity ◽  
Available Water ◽  
Eastern Australia ◽  
North Eastern ◽  
Poorly Drained Soils

A comparative study of the available water storage capacity of three soils under Townsville stylograss vegetation is reported. Two of the soils were selected as representing solodized-solonetz and solodic soils typical of extensive areas of eastern Australia, yet differing greatly in their demonstrated productivity after fertilization. The third selection was a well-drained, highly productive soil. After fuli recharge, available soil water in the three soils above 1.5 m was 80, 150, 180f mm. Subsequent root density and soil water content profiles indicated that differences in water entry, and not in completeness of withdrawal, accounted for differences in storage. The difficulties of estimating the storage capacity of poorly drained soils is discussed. A technique is described which uses total porosity for estimation of the upper limit of the available water range and the distribution of total soluble salts as an indicator of the depth of water entry.

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