scholarly journals Digital mapping of soil erodibility for water erosion in New South Wales, Australia

Soil Research ◽  
2018 ◽  
Vol 56 (2) ◽  
pp. 158 ◽  
Author(s):  
Xihua Yang ◽  
Jonathan Gray ◽  
Greg Chapman ◽  
Qinggaozi Zhu ◽  
Mitch Tulau ◽  
...  

Soil erodibility represents the soil’s response to rainfall and run-off erosivity and is related to soil properties such as organic matter content, texture, structure, permeability and aggregate stability. Soil erodibility is an important factor in soil erosion modelling, such as the Revised Universal Soil Loss Equation (RUSLE), in which it is represented by the soil erodibility factor (K-factor). However, determination of soil erodibility at larger spatial scales is often problematic because of the lack of spatial data on soil properties and field measurements for model validation. Recently, a major national project has resulted in the release of digital soil maps (DSMs) for a wide range of key soil properties over the entire Australian continent at approximately 90-m spatial resolution. In the present study we used the DSMs and New South Wales (NSW) Soil and Land Information System to map and validate soil erodibility for soil depths up to 100 cm. We assessed eight empirical methods or existing maps on erodibility estimation and produced a harmonised high-resolution soil erodibility map for the entire state of NSW with improvements based on studies in NSW. The modelled erodibility values were compared with those from field measurements at soil plots for NSW soils and revealed good agreement. The erodibility map shows similar patterns as that of the parent material lithology classes, but no obvious trend with any single soil property. Most of the modelled erodibility values range from 0.02 to 0.07 t ha h ha–1 MJ–1 mm–1 with a mean (± s.d.) of 0.035 ± 0.007 t ha h ha–1 MJ–1 mm–1. The validated K-factor map was further used along with other RUSLE factors to assess soil loss across NSW for preventing and managing soil erosion.

Soil Research ◽  
1990 ◽  
Vol 28 (4) ◽  
pp. 659 ◽  
Author(s):  
JL Armstrong

Three 41 m long bare fallow plots were established on a chocolate soil (Mollisol) at Inverell in late 1976 to determine the soil erodibility (K) factor for use in the Universal Soil Loss Equation (USLE). The K-factor was estimated as 0.018 tonne hectare hour per hectare megajoule millimetre, indicating a soil of low to moderate erodibility. This value was close to that predicted from the soil erodibility nomograph used in the USLE. The average annual soil loss over the eight year period was 51 t/ha, while the largest individual storm soil loss from the plots was 47 t/ha. The two largest soil losses in each year accounted for 60-99% of the annual soil loss. Various erosivity indices were examined for their ability to predict runoff and soil loss from individual erosive storms. Indices which had separate variables for soil particle detachment (energy component) and particle transport (runoff component) were superior, although a large proportion of the variation in runoff and soil loss remained unaccounted for, and the possible reasons for this are examined. The highest correlation was obtained between soil loss and runoff amount.


1998 ◽  
Vol 12 (6) ◽  
pp. 951 ◽  
Author(s):  
Jiýí Kolibác

Four new species of the family Thanerocleridae are described from Australia (Queensland, New South Wales): Isoclerus (Isoclerus) rumcajs, I. (I.) manka, I. (I.) cipisek and I. (I.) gerstmeieri. These species are the first records of the family’s autochthonous members from the Australian continent. The subgenus Isoclerus (Lyctosoma) Lewis is synonymised with Isoclerus (Isoclerus) Lewis. Hypotheses concerning the biogeography of subtribe Isoclerina Kolibáÿč in which the newly described species belong, are proposed. The ancestral area of Isoclerina may be in Africa or somewhere in the region of Europe, Greenland and the eastern part of North America – in either case, in the Lower to Middle Cretaceous era. Also, pan-biogeographic hypotheses are formulated for the distribution patterns of species of the subgenus Isoclerus.


1994 ◽  
Vol 34 (7) ◽  
pp. 1069 ◽  
Author(s):  
E Humphreys ◽  
WS Meyer ◽  
SA Prathapar ◽  
DJ Smith

This paper reviews field measurements of evapotranspiration from rice (ET rice) in the Murrumbidgee Valley of southern New South Wales. The results are compared with US Class A open pan evaporation (E pan) at CSIRO Griffith, and with reference evapotranspiration (ETo) calculated using a locally calibrated Penman equation. Both methods (+ETrice = +Epan or +ETrice = +ETo) give good estimates of total evapotranspiration from flooded rice over the ponded season of about 5 months, from October to February. Variation between seasons in total ETo, rainfall, and ETo minus rainfall is large. Over 32 years, total seasonal ETo varied by a factor of 1.5, while rainfall varied >10-fold. The irrigation water requirement for rice +(ETo - rainfall) varied from 685 mm in 1992-93 to 1350 mm in 1990-91. This large variation highlights the need to adjust the rice water use limit (16 ML/ha or 1600 mm) on a seasonal basis, to detect and eliminate high water use paddocks where percolation to the groundwater or surface runoff is excessive (>2 ML/ha). On average, an irrigation requirement of 10.5 ML/ha is needed to replace net evaporative loss +(ETo - rainfall) for rice flooded for 5 months, October-February. Monthly totals of ETo are compared for several locations within the rice-growing areas of southern New South Wales, and differences between locations are found to be small and not significant. This reflects the strong dependence of evaporation on radiant energy, which is unlikely to vary spatially to a significant extent across the region. ETo calculated from meteorological data collected at CSIRO Griffith therefore provides a definitive basis for estimating evapotranspiration from rice in southern New South Wales. Furthermore, CSIRO Griffith has a computerised meteorological data base going back to the 1930s. Current meteorological data and historical records are readily available by contacting the Metdata Manager. Therefore, the case is made for using CSIRO Griffith ETo as the reference for estimating evapotranspiration from rice in southern New South Wales. This study provides farmers, Land and Water Management Plan groups, and policy makers with a tool that can be used, on a yearly basis, to evaluate rice paddock water use efficiency. It should be adopted to confine rice growing to the least permeable soils.


Soil Research ◽  
2015 ◽  
Vol 53 (2) ◽  
pp. 216 ◽  
Author(s):  
Xihua Yang

The Universal Soil Loss Equation (USLE) and its main derivate, the Revised Universal Soil Loss Equation (RUSLE), are widely used in estimating hillslope erosion. The effects of topography on hillslope erosion are estimated through the product of slope length (L) and slope steepness (S) subfactors, or LS factor, which often contains the highest detail and plays the most influential role in RUSLE. However, current LS maps in New South Wales (NSW) are either incomplete (e.g. point-based) or too coarse (e.g. 250 m), limiting RUSLE-based applications. The aim of this study was to develop automated procedures in a geographic information system (GIS) to estimate and map the LS factor across NSW. The method was based on RUSLE specifications and it incorporated a variable cutoff slope angle, which improves the detection of the beginning and end of each slope length. An overland-flow length algorithm for L subfactor calculation was applied through iterative slope-length cumulation and maximum downhill slope angle. Automated GIS scripts have been developed for LS factor calculation so that the only required input data are digital elevation models (DEMs). Hydrologically corrected DEMs were used for LS factor calculation on a catchment basis, then merged to form a seamless LS-factor digital map for NSW with a spatial resolution ~30 m (or 1 s). The modelled LS values were compared with the reference LS values, and the coefficient of efficiency reached 0.97. The high-resolution digital LS map produced is now being used along with other RUSLE factors in hillslope erosion modelling and land-use planning at local and regional scales across NSW.


1989 ◽  
Vol 29 (1) ◽  
pp. 51 ◽  
Author(s):  
DC McKenzie ◽  
HB So

The effect of gypsum on the properties and crop productivity of 6 contrasting vertisols of the Gwydir Valley, New South Wales was investigated in 1978 and 1979. These soils are often used for dryland wheat production, although crop growth is generally restricted by their structural instability. In 2 of the soils used in our study, the surface aggregates were sodic and dispersive (poor soils), 2 were relatively stable when wetted (good soils), whilst the other 2 soils had surface aggregates that were intermediate in behaviour (intermediate soils). The effects of added gypsum at 4 rates (0, 2.5, 5.0 and 7.5 t ha-1) on soil water profiles, soil properties and the growth of wheat were monitored over a 2 year period. Dryland wheat grain yields were increased by as much as 230% following the application of gypsum. Benefits were most pronounced on clays with sodic topsoils, a high water-holding capacity and adequate nutrition; plant response to gypsum on nearby soils with non-dispersive surfaces was less pronounced. Yield increases were associated with better seedling establishment, greater tiller production, increased grain weight, and lower incidence of 'Crown Rot' disease. Plant response to gypsum was related to improved water penetration into the soil, allowing greater storage of water in the subsoil, rather than loss via evaporation and possibly runoff. Increases as high as 137% in the soil water storage to a depth of 1.2 m were observed. Crop performance was also strongly influenced by rainfall, time of sowing and weed control. Where nitrogen and, to a lesser extent, phosphorus, were deficient in gypsum-treated soil, they had to be added before the extra soil water could be utilised effectively by wheat. On the lighter textured clays, gypsum appeared to aggravate nitrogen deficiency, apparently because of enhanced leaching.


1994 ◽  
Vol 34 (1) ◽  
pp. 75 ◽  
Author(s):  
DL Chen ◽  
JR Freney ◽  
AR Mosier ◽  
PM Chalk

The effects of the nitrification inhibitors nitrapyrin, acetylene (provided by wax-coated calcium carbide), and phenylacetylene on nitrogen (N) transformations and denitrification losses following presowing applications of urea were determined in a cottonfield in the Namoi Valley of New South Wales. The study used 0.05-m-diameter microplots to follow the changes in mineral N, and 0.15-m-diameter microplots fertilised with 15N-labelled urea (6 g N/ m2; 5 atom % 15N) to assess losses of applied N. When urea was applied in February (34 weeks before sowing), 84% of applied N was lost from the soil. Loss of applied N was reduced by addition of nitrapyrin and phenylacetylene, to 53 and 57%, respectively. In the absence of nitrification inhibitors, less N was lost (72% of that applied) from an application in May than from the February application. Addition of acetylene, phenylacetylene, and nitrapyrin reduced losses over the 24 weeks to sowing to 57, 52, and 48%, respectively. These experiments show that N loss from presowing applications of urea can be significantly reduced by the use of nitrification inhibitors, but that the losses of N are still substantial.


1994 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
AJK Millar ◽  
GT Kraft

This catalogue lists 139 species (in 12 orders, 26 families and 63 genera) of brown algae from New South Wales and Lord Howe Island. More than half (71) are endemic to Australia, with the remainder being very widely distributed (e.g. Europe, the Americas and Asia); 28 species have New South Wales type localities (14 from the mainland and 14 from Lord Howe Island). As a result of extensive searching of archival records, the exact locality of many 'Nov. Holl.' types is deduced to be the Sydney region of New South Wales. Four genera (Austronereia, Nemacystis, Nereia and Tomaculopsis) and 10 species are newly recorded, six species being new to the Australian continent. The largest genus represented is Sargassum, for which 37 species have been recorded, including 10 based on local types. Eleven of these Sargassum records are eliminated, the remaining 26 are in urgent need of regional monographic treatment. Eclipsed only by the Fucales (39 species in 9 genera), the order Dictyotales with 36 species in 13 genera, is the dominant group in terms of cover and possibly biomass along the mainland and at Lord Howe Island from low intertidal habitats to to depths of at least 35 m. In many areas of the seabed, brown algae and the cmstose corallines seem to be especially resilient to grazing by the sea-urchin Centrostephanis rodgersii which is presently besieging this coast.


2009 ◽  
Vol 57 (2) ◽  
pp. 77 ◽  
Author(s):  
Gopal Murugan ◽  
Hortencia Obregón-Barboza ◽  
Alejandro M. Maeda-Martínez ◽  
Brian V. Timms

The only species of the genus Triops in Australia, T. australiensis, is found to reproduce by gonochorism. Morphological and reproductive data and molecular analyses of fragments of mitochondrial genes 12S rRNA (12S) and cytochrome oxidase I (COI) indicate that a Triops population from the middle Paroo in north-western New South Wales is composed of two different entities, Triops cf. australiensis lineage A, and T. cf. australiensis lineage B. Gonad histology in individuals with ovisacs of lineage A revealed no evidence of testicular tissue; however, large testicular lobes were found in individuals with ovisacs of lineage B, indicating that they were anatomically hermaphrodites. This is the first record of Australian hermaphroditic Triops. For each lineage, a single haplotype of each gene was obtained. Molecular genetic distance and phylogenetic analyses confirmed the closer relationship and monophyly of the two lineages with T. australiensis (GenBank) when compared with Triops species from other continents. COI haplotypes of lineage A and lineage B differed by 7.7% from each other and differed by 10.2% and 9.6% from a published T. australiensis sequence, respectively. The 12S haplotypes of lineage A and lineage B differed by 3.3% from each other and differed by 2% and 2.5% from a published T. australiensis sequence, respectively. Our results suggest that the two co-occurring Triops lineages probably represent two species that are distinct from T. australiensis.


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