Peter Lockwood

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Juncus ensifolius Wikstr

https://thekeep.eiu.edu/herbarium_specimens_byname/16650/thumbnail.jp

Acid soils and soil acidification on the Northern Tablelands of New South Wales, Australia

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Attitudes shifting to the train side of the tracks

Planning News, May 1, 2014

The Eastern Transport Coalition recently held a transport summit and it was remarkable how much a... more The Eastern Transport Coalition recently held a transport summit and it was remarkable how much attitudes to the issue have shifted since we last did this over five years ago. I was surprised because after 20 years representing the area as a Member of Parliament and Councillor, I was well used to the preference for cars.

Rosa palustris Marsh

Rubus strigosus Michx

Artemisia vulgaris L

Spiraea tomentosa L

https://thekeep.eiu.edu/herbarium_specimens_byname/7591/thumbnail.jp

Polygonum hydropiperoides Michx

The Environmental Fate and Behaviour of Antimony in the Coastal Floodplain System of the Macleay Catchment, with Comparisons to Arsenic

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The effect of sodicity on cotton: Does soil chemistry or soil physical condition have the greater role?

Crop & Pasture Science, 2013

Soil sodicity is widespread in the cracking clays used for irrigated cotton (Gossypium hirsutum L... more Soil sodicity is widespread in the cracking clays used for irrigated cotton (Gossypium hirsutum L.) production in Australia and worldwide and sometimes produces nutrient imbalances and poor plant growth. It is not known whether these problems are due primarily to soil physical or to soil chemical constraints. We investigated this question by growing cotton to maturity in a glasshouse in large samples of a Grey Vertosol in which the exchangeable sodium percentage (ESP) was adjusted to 2, 13, 19, or 24. A soil-stabilising agent, anionic polyacrylamide (PAM), was added to half the pots and stabilised soil aggregation at all ESPs. Comparison of the effect of ESP on cotton in the pots with and without PAM showed that, up to ESP of 19, the soil physical effects of sodicity were mainly responsible for poor cotton performance and its ability to accumulate potassium. At ESP >19, PAM amendment did not significantly improve lint yield, indicating that soil chemical constraints, high plant sodium concentrations (>0.2%), and marginal plant manganese concentrations limited plant performance. Further research into commercial methods of amelioration of poor physical condition is warranted rather than application of more fertiliser.

Scirpus atrocinctus Fernald

https://thekeep.eiu.edu/herbarium_specimens_byname/16648/thumbnail.jp

Symphoricarpos albus (L.) Blake

Integrating scattered trees into grazing landscapes to manage soil sustainably

EGUGA, May 1, 2010

Acting as keystone structures, scattered paddock trees play an important ecosystem service in the... more Acting as keystone structures, scattered paddock trees play an important ecosystem service in the Australian grazing environment through influencing their immediate environment both above-and below-ground. Since these trees are rapidly being lost from the landscape, there is a need to understand their functions more fully in order to manage the landscape in a sustainable manner. This study aims to quantify how single trees influence the soil resource with depth, and to investigate the spatial extent of this influence. Once these aspects have been quantified, the optimum distribution required to remediate depleted soil conditions can then be estimated. Three isolated trees were comprehensively examined for their influence on soil chemistry to a depth of 75cm and to a radial distance of more than 3.5 canopy radii. Soil moisture, total C, N and S, extractable P, pH (1:5 CaCl2 & H2O) and EC were examined. The trees modification on soil condition was strongly dependent on the soil property examined, although typically values were higher under the tree at the surface and diminished with distance both horizontally and vertically. We conclude that single trees significantly improve soil condition and that a distance of 2.5 canopy radii is sufficient to explain the spatial influence of scattered trees. Further work is now underway to elucidate the processes that influence soils around these trees. This work will link pasture productivity and pasture quality with soil attributes in order to fully quantify the ecosystem services these trees provide in order to sustainably manage this environment, both above-and below-ground.

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Cyperus dentatus Torr

Polygala nuttallii Torr. & A. Gray

https://thekeep.eiu.edu/herbarium_specimens_byname/7589/thumbnail.jp

Abies homolepis Siebold & Zucc

https://thekeep.eiu.edu/herbarium_specimens_byname/7584/thumbnail.jp

Impact of waterlogging on the nutrition of cotton (Gossypium hirsutum L.) produced in sodic soils

Crop & Pasture Science, 2013

Sodicity in Vertosols used for agricultural production can adversely affect the growth and nutrit... more Sodicity in Vertosols used for agricultural production can adversely affect the growth and nutrition of cotton (Gossypium hirsutum L.) plants. Cotton produced in sodic soils has reduced dry matter and lint yield and can develop toxic plant tissue concentrations of sodium (Na) but limited tissue concentrations of phosphorus (P,) potassium (K), and micronutrients. Crops produced on sodic soils frequently suffer from aeration stress after an irrigation or rainfall event, and it was hypothesised that the adverse physical and/or chemical conditions of sodic soils may exacerbate the effects of waterlogging. We measured the impacts of sodicity on the growth, nutrition, and root recovery time of cotton during and after waterlogging in two experiments. In the first, cotton plants were subjected to a 7-day period of inundation in Grey Vertosols with a range of exchangeable sodium percentage (ESP) values from 2 to 25%; 32 P was placed in the pots and its accumulation in the plant was used to indicate root activity and recovery after the waterlogging event. In a second experiment, agar was dissolved in nutrient solutions with a range of Na concentrations (9, 30, and 52 mM) matching soil solution Na concentrations in sodic soils, in order to simulate a waterlogging event. Following the waterlogging event, the solutions were labelled with 32 P, in order to determine the effect of sodic soil solution chemistry on the rate of recovery of cotton root function after the event. Plant nutrient analysis was used to determine the effects of sodicity and waterlogging on cotton nutrition. In both experiments, waterlogging reduced root activity and reduced the uptake and transport of labelled P by the cotton plants, decreased plant P and K concentrations, and increased the plant Na concentrations. Sodicity exacerbated the effects of waterlogging on root function and cotton nutrition in the soil experiment but not in the nutrient solution experiment, suggesting that any contribution of waterlogging to the patterns of nutrient accumulation in cotton crops produced in sodic fields occurs due to soil physical factors rather than soil solution chemistry.

format_quoteHigher soil sodicity delayed labeled P uptake by 183% in waterlogged treatments, indicating severe nutrient recovery challenges in sodic conditions (P < 0.001).format_quote

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Carex collinsii Nutt

https://thekeep.eiu.edu/herbarium_specimens_byname/16727/thumbnail.jp

Optimum Management of White Cypress Pine ('Callitris glaucophylla'): Individuals to Landscapes

Professor Brian Sindel. I have been most fortunate to have received unwavering support from my su... more Professor Brian Sindel. I have been most fortunate to have received unwavering support from my supervisory team, each of whom have supported me throughout the logistical, technical and financial challenges central to the completion of such a project. I would especially like to thank Dr. Wilson for his ongoing assistance with all aspects of the project and for providing me with industry exposure, which has helped broaden my understanding of the challenges facing natural resource management. This project would never have been completed without the substantial technical assistance provided by John Lemon, who I now consider to be a great friend even despite our heated conversations about soil sampling in even hotter weather! At this point I must also thank Andrew Harrison for giving up many weekends and holidays to assist me with sampling and menial laboratory tasks. I am eternally grateful for Andrew's technical expertise and patience. Finally, to Christiaan O'Brien and Stephen Parker who have remained great friends and who managed to stay smiling even whilst sieving over 1000 litter samples! To the numerous contributors to this research, I extend my sincere thanks. Leanne Lisle (UNE), David Donnelly and Vicki Fermor (NSW Department of Environment and Climate Change) provided substantial laboratory and technical expertise to various sections of the project. Greg Chamberlain and David Edmonds (UNE) assisted with the management experiment. Dr. Lachlan Copeland (UNE) lent his enormous knowledge of NSW plants to the management experiment and Dr. Ivor Growns (NSW Department of Water and Energy) and Dr. Matthew Tighe (UNE) applied their equally substantial statistical knowledge to some very challenging data throughout the project. v I would like to thank the staff in the former NSW Department of Natural Resources (now DWE, DECC and the Catchment Management Authority) building on campus for their support and assistance throughout the project, especially Dr.

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Characterizing the Plant and Soil Interactions That Affect the Growth and Nutrition of Cotton (Gossypium Hirsutum L.) in Sodic Vertosols

format_quoteHigher sodicity levels in soil correlated with reduced P and K concentrations in cotton, emphasizing nutrient management challenges.format_quote

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Peter Lockwood

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