![Dr Gunnar Kirchhof](/sites/default/files/profiles/901.jpeg)
Overview
Background
May 2002–ongoing: Senior Lecturer Land Resources Sciences, Principla Research Fellow, School of Land, Crop and Food Sciences; The University of Queensland, Australia
As lecturer of Land Resources Sciences at the University of Queensland, Dr Kirchhof has both led and collaborated on over half a dozen projects, and supervised numerous research staff and students. His research has focussed on:
- Soil–Water relationships;
- Conservation Agriculture and Irrigation scheduling
- Soil erosion
- Water and Nutrient Balances;
- Spatial Variability of Soil Properties from Ped to Landscape Scales;
- Dry-land Salinity Management;
- Water Recycling
- Computer Modelling of Water Flow with Special Reference to Variability and assessment of deep drainage
- Knowledge Management;
2011-15 Course leader: Australia Awards in Africa Dryland Farming/Soil and Water conservation Short Course Awards, UniQuest; Australia and Africa, Dr Kirchhof led the design and delivery of the AusAID-funded Dryland Farming Short Course Award, contracted to UniQuest/UQ-ID through GRM International, which was delivered twice a year in 2011 and 2014.
Countries of work experience: Indonesia, Vietnam, Papua New Guinea, the Philippines, Burkino Faso, Côte d’Ivoire, Djibouti, Ethiopia, Nigeria, Tunisia, Uganda, Kenya, Tunisia, Australia.
Previous postions:
Oct 1997–May 2002: Senior Soil Scientist, Soil Conservation, NSW Agriculture; Australia
Mar 1996–Oct 1997: Soil Physicist, International Institute of Tropical Agriculture; Ibadan, Nigeria
Dec 1991–Mar 1996: Research Fellow, Department of Agriculture, The University of Queensland; Brisbane
Jan 1989–Dec 1991: Soil Scientist, CASSIRO Ltd, Wauchope, NSW
Availability
- Dr Gunnar Kirchhof is:
- Available for supervision
- Media expert
Fields of research
Qualifications
- Postgraduate Diploma in Education, The University of Queensland
Research interests
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Soil and Water Management
Water in the soil environment and landscapes: even though it is usually not considered a nutrient, it can in fact be seen as the most important nutrient. It drives productivity of our ago-ecosystems as well their sustainability. Water must be used efficiently, what can efficient water use achieve? What are the limits of this efficiency?
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Conservation Agriculture
Conservation Agriculture (CA) is considered the current best management practice for sustainable and productive ago-ecosystems. Is this correct? - May be not? We need to know more about practical suitability of CA in a range of environments, especially in Africa as wholesale promotion of CA can be detrimental to its adoption potential. The big questions are: is it a management method to satisfy world food demand? Can it be used to mitigate or manage climate change? What are its limitations?
Research impacts
Conservation Agriculture – achieving impact in Africa
http://www.australiaawardsafrica.org/news/conservation-agriculture-achieving-impact-in-africa/
Works
Search Professor Gunnar Kirchhof’s works on UQ eSpace
2022
Other Outputs
Strengthening capacities to innovate through North-South collaborative agricultural research in Papua New Guinea
Kirchhof, Gunnar (2022). Strengthening capacities to innovate through North-South collaborative agricultural research in Papua New Guinea. Asia-Pacific Islands Rural Advisory Services Network (APIRAS) Hyderabad Telangana, India: Food and Agriculture Organization of the United Nations.
2022
Journal Article
Responses of soil organic carbon, aggregate diameters, and hydraulic properties to long-term organic and conventional farming on a Vertisol in India
Schweizer, Steffen A., Graf-Rosenfellner, Markus, Bhat, Nisar A., Kayser, Gilles, Sisodia, Bhupendra S., Kirchhof, Gunnar, Zikeli, Sabine, Cadisch, Georg and Bhullar, Gurbir S. (2022). Responses of soil organic carbon, aggregate diameters, and hydraulic properties to long-term organic and conventional farming on a Vertisol in India. Land Degradation and Development, 33 (5), 785-797. doi: 10.1002/ldr.4216
2021
Journal Article
50 years of continuous no-tillage, stubble retention and nitrogen fertilization enhanced macro-aggregate formation and stabilisation in a Vertisol
Hati, Kuntal M., Jha, Pramod, Dalal, Ram C., Jayaraman, Somasundaram, Dang, Yash P., Kopittke, Peter M., Kirchhof, Gunnar and Menzies, Neal W. (2021). 50 years of continuous no-tillage, stubble retention and nitrogen fertilization enhanced macro-aggregate formation and stabilisation in a Vertisol. Soil and Tillage Research, 214 105163, 1-11. doi: 10.1016/j.still.2021.105163
2021
Conference Publication
Sweetpotato yield comparison from pathogen tested and non-pathogen tested vines with coffee pulp in the PNG Highlands
Yeffrey, Yapo, Sirabis, William, Wehr, Bernhard, Menzies, Neal and Kirchhof, Gunnar (2021). Sweetpotato yield comparison from pathogen tested and non-pathogen tested vines with coffee pulp in the PNG Highlands. The Soil Science Australia and the New Zealand Society of Soil Science Joint Conference., Cairns, QLD Australia, 27 June - 2 July 2021.
2021
Conference Publication
Soil fertility management techniques for increased sweetpotato root yield in Papua New Guinea (PNG) highlands
Jeffrey, Yapo, Sirabis, William, Atung, Cyril, Ramakrishna, Akkinapally, Wehr, Bernhard, Menzies, Neal and Kirchhof, Gunnar (2021). Soil fertility management techniques for increased sweetpotato root yield in Papua New Guinea (PNG) highlands. The Soil Science Australia and the New Zealand Society of Soil Science Joint Conference, Cairns, QLD Australia, 27 June - 2 July 2021.
2021
Journal Article
Gamma irradiation with 50 kGy has a limited effect on agronomic properties of air-dry soil
Wehr, J. Bernhard and Kirchhof, Gunnar (2021). Gamma irradiation with 50 kGy has a limited effect on agronomic properties of air-dry soil. Soil Systems, 5 (2) 28, 28. doi: 10.3390/soilsystems5020028
2020
Other Outputs
Sustaining soil fertility in support of intensification of Sweetpotato cropping systems
Wehr, Bernhard, Kirchhof, Gunnar and Menzies, Neal (2020). Sustaining soil fertility in support of intensification of Sweetpotato cropping systems. Canberra, ACT, Australia: ACIAR.
2020
Conference Publication
Assessment of soil structural properties in relation to land use change in South-East Asia
Lastic, Rachel de, Hoàng, Thảo, Nguyen, Phuong, Son, Sovanda, Suos, Vuthy and Kirchhof, Gunnar (2020). Assessment of soil structural properties in relation to land use change in South-East Asia. The Third International Tropical Agriculture Conference TropAg 2019 , Brisbane, QLD Australia, 11–13 November 2019. Basel, Switzerland: MDPI. doi: 10.3390/proceedings2019036182
2020
Conference Publication
Jatropha curcas development as intervention potential to tackling land, energy and food challenges of rural communities in dryland sub-Saharan Africa
Ogunwole, Joshua, Kirchhof, Gunnar, Birhanu, Birhanu Z., Duiker, Sjoerd and Pires, Luiz F. (2020). Jatropha curcas development as intervention potential to tackling land, energy and food challenges of rural communities in dryland sub-Saharan Africa. Third International Tropical Agriculture Conference (TROPAG 2019), Brisbane, Australia, 11-13 November 2019. Basel, Switzerland: MDPI . doi: 10.3390/proceedings2019036085
2019
Other Outputs
Sustaining soil fertility in support of intensification of Sweetpotato cropping systems
Wehr, Bernhard, Kirchhoff, Gunnar and Menzies, Neal (2019). Sustaining soil fertility in support of intensification of Sweetpotato cropping systems. Canberra, ACT, Australia: ACIAR.
2018
Journal Article
Management of the major chemical soil constraints affecting yields in the grain growing region of Queensland and New South Wales, Australia – a review
Page, K. L., Dalal, R. C., Wehr, J. B., Dang, Y. P., Kopittke, P. M., Kirchhof, G., Fujinuma, R. and Menzies, N. W. (2018). Management of the major chemical soil constraints affecting yields in the grain growing region of Queensland and New South Wales, Australia – a review. Soil Research, 56 (8), 765-779. doi: 10.1071/sr18233
2018
Journal Article
Root zone temperature alters storage root formation and growth of sweetpotato
Taranet, P., Kirchhof, G., Fujinuma, R. and Menzies, N. (2018). Root zone temperature alters storage root formation and growth of sweetpotato. Journal of Agronomy and Crop Science, 204 (3), 313-324. doi: 10.1111/jac.12262
2018
Journal Article
Intensified sweetpotato production in Papua New Guinea drives plant nutrient decline over the last decade
Fujinuma, Ryosuke, Kirchhof, Gunnar, Ramakrishna, Akkinapally, Sirabis, William, Yapo, Jeffery, Woruba, Deane, Gurr, Geoff and Menzies, Neal (2018). Intensified sweetpotato production in Papua New Guinea drives plant nutrient decline over the last decade. Agriculture, Ecosystems & Environment, 254, 10-19. doi: 10.1016/j.agee.2017.11.012
2017
Journal Article
The effect of salinity on plant-available water
Sheldon, Anna R., Dalal, Ram C., Kirchhof, Gunnar, Kopittke, Peter M. and Menzies, Neal W. (2017). The effect of salinity on plant-available water. Plant and Soil, 418 (1-2), 477-491. doi: 10.1007/s11104-017-3309-7
2017
Journal Article
Growth and yield response of glasshouse- and field-grown sweetpotato to nitrogen supply
Taranet, Prapa, Harper, Stephen, Kirchhof, Gunnar, Fujinuma, Ryosuke and Menzies, Neal (2017). Growth and yield response of glasshouse- and field-grown sweetpotato to nitrogen supply. Nutrient Cycling in Agroecosystems, 108 (3), 309-321. doi: 10.1007/s10705-017-9858-6
2017
Book
Technical Management of soil physical and chemical constraints to grains cropping in Queensland and New South Wales: A review. Technical Final report (UQ00084)
Menzies, Neal , Page, Kathryn , Dalal, Ram , Dang, Yash , Kopittke, Peter , Wehr, Bernhard , Orton, Thomas , Kirchhof, G. and Fujinuma, R. (2017). Technical Management of soil physical and chemical constraints to grains cropping in Queensland and New South Wales: A review. Technical Final report (UQ00084). Canberra, ACT, Australia: GRDC.
2016
Journal Article
Pests, diseases and crop protection practices in the smallholder sweetpotato production system of the highlands of Papua New Guinea
Gurr, G.M., Johnson, A.C., Waruba, D.N., Kirchhof, G., Fujinuma, R., Sirabis, W., Jeffery, Y. and Akkinapally, R. (2016). Pests, diseases and crop protection practices in the smallholder sweetpotato production system of the highlands of Papua New Guinea. PeerJ, 4 (12) e2703, e2703. doi: 10.7717/peerj.2703
2016
Journal Article
Pests, diseases and crop protection practices in the smallholder sweetpotato production system of the highlands of Papua New Guinea
Gurr, Geoff M., Liu, Jian, Johnson, Anne C., Woruba, Deane N., Kirchhof, Gunnar, Fujinuma, Ryosuke, Sirabis, William, Jeffery, Yapo and Akkinapally, Ramakrishna (2016). Pests, diseases and crop protection practices in the smallholder sweetpotato production system of the highlands of Papua New Guinea. PeerJ, 4 (12) e2703. doi: 10.7287/peerj.preprints.2394
2014
Journal Article
Early response of soil properties and function to riparian rainforest restoration
Gageler, Rose, Bonner, Mark, Kirchhof, Gunnar, Amos, Mark, Robinson, Nicole, Schmidt, Susanne and Shoo, Luke P. (2014). Early response of soil properties and function to riparian rainforest restoration. PLoS One, 9 (8) e104198, e104198.1-e104198.8. doi: 10.1371/journal.pone.0104198
2011
Book Chapter
Puddling: effect on soil physical properties and crops
Kirchhof, Gunnar, Tuong, T. P. and So, H. B. (2011). Puddling: effect on soil physical properties and crops. Encyclopedia of agrophysics. (pp. 667-668) edited by Jan Gliński, Józef, Horabik and Jerzy Lipiec. Dordrecht, Netherlands: Springer. doi: 10.1007/978-90-481-3585-1_129
Funding
Current funding
Supervision
Availability
- Dr Gunnar Kirchhof is:
- Available for supervision
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Available projects
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Runoff and erosion from very dry clay soil surfaces: does conventional infiltration theory apply?
Accepted conventional infiltration theory states that application of water to dry soil over time follows two phases: first, the sorptive phase where capillarity rapidly fills the pore system, and the steady state phase where the pore system conducts water at the rate of the soil saturated hydraulic conductivity. In most cases, this is also what we observe in the field: water enters the soil quickly and it then slows down to reach a steady rate. This infiltration theory assumes that the wetting angle of the capillaries is 0°; i.e. the capillary has a water film. If the wetting angle is larger than 0°, the capillary potential that drives water intake during the sorptive phase will also be much smaller, resulting in slow sorptivity. On hydrophobic soils, the wetting angle can approach 90° or, in extreme cases become convex.
Applying water to very dry soil, perhaps after a long drought, or soil surfaces that were exposed to bushfires or soils with water repellent organic matter, may not have a capillary water film that allows immediate rapid water intake. Under field conditions this can occasionally be observed when water is applied to very dry soil: it initially ponds on the surface before it then quickly infiltrates. This initial ponding may be the consequence of a larger than 0° wetting angle. The length of initial ponding will affect the onset of runoff and erosion. Although the problem of hydrophobicity is a well-known problem on sandy soils, water repellence on clay soils has been observed but is not well understood.
This project aims to verify if the sorptive phase can be preceded by a ponded phase and under what conditions it can occur. The experimental plan would assess the impact of soil type and texture, soil organic matter, and antecedent soil water content on the formation of an initial potential ponded phase. The research would initially be conducted under laboratory conditions using intact soil cores (St Lucia or Gatton Research Labs) and possibly followed up for in situ field conditions.
The results will have implications on how to prepare and avoid runoff and erosion from very dry soils during a heavy rainfall event.
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Quantifying the interaction between soil organic matter, nitrogen fertiliser and hydraulic conductivity on the Hermitage Long term Trials
The Hermitage Long Term trial has been running since 1968. The trial assessed a range of agronomic and soil science responses to conservation agriculture type practices and fertilisation regimes. Much data has been collected over the years with the most recent being submitted for publication by Kuntal Hatia et al. late 2020. This paper provides excellent data for soil aggregation as a consequence of tillage methods, stubble retention, and nitrogen fertilisation. Another important dataset is the impact of these management parameters on saturated hydraulic conductivity and the van Genuchten hydraulic conductivity model. This project aims to measure in situ saturated hydraulic conductivity using rainfall simulation and nitrometers as well as collecting undisturbed cores for Ksat and pF-curve determination to parameterise the van Genuchten model. The aim is to publish a follow-up paper with Kuntal Hatia et al.
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Can ground cover-induced concentrated flow increase soil erosion?
Maintaining adequate ground cover is the ‘golden’ rule to reduce soil erosion. Leaf litter or similar absorbs the kinetic energy of rain drops as they hit the soil surface. This reduces soil surface disturbance and prevents aggregate breakdown that can lead to the formation of a surface seal. Under some conditions, however, in particular on steep slopes, adequate ground cover may not protect the soil from erosion even if the soil hydraulic conductivity exceeds rainfall intensity. The mechanism that can lead to runoff and then erosion may be due to the formation of concentrated flow.
Consider a thought experiment: our soil surface has a saturated hydraulic conductivity of 30 mm/h and we have a rainfall intensity of 20 mm/h: we should not get runoff! Now 50% of the soil is covered and hence, only 50% of the soil surface can take in water. This means that the hydraulic conductivity of the uncovered soil must be at least 40 mm/h to prevent runoff (i.e. 20 mm/h from the rainfall plus 20 mm/h that enters the soil as runoff from the groundcover). Therefore we would have runoff as the hydraulic conductivity is only 30 mm/h. Of course, this thought experiment does not apply to the real world, but the principle is still valid.
This project aims to assess the impact of groundcover on the formation of concentrated flow. The experimental plan would assess the effect of soil hydraulic conductivity, slope, and ground cover type and quantity on runoff and erosion. The project will be conducted at the Erosion Processes Laboratory at the St Lucia campus and can be supplemented in-situ using our field rainfall simulator and infiltrometer equipment.
The results will have implications on recommended management practices of sloping soil to prevent soil erosion.
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Reducing wind erodibility through increasing aggregate stability through mulch management
The soil property that primarily drives susceptibility to wind erosion is aggregate size distribution. On soils that are susceptible to wind erosion, management practices to reduce wind erosion aim to increase aggregate sizes. This can be achieved by mulch application that leads to an increase in soil organic matter and re-aggregation of soil structure during wetting and drying cycles. How effective mulch application will be is likely to be dependent on the quantity and type or mulch applied. This project aims to assess aggregate size distribution as measured by dry sieving in response to wet-dry cycles and mulch type and quantity. The experiment will be carried out either at Gatton or St Lucia. It will run over two semesters to ensure sufficient breakdown of applied mulch under a number of wet-dry cycles
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Micro-topography of soil surfaces and its effect on erosion
Soil erodibility by water is strongly affected soil surface roughness. The description of surface roughness in relation to erosion is surface water storage capacity which is the volume of water that is can be held in the surface depressions before the overflow, and the surface roughness per se that is commonly expressed as the Manning coefficient. Three-dimensional mapping of the soil surface is an alternative, though not very well researched alternative, to assess erodibility of soil surfaces. Close-range photogrammetry can potentially be used to generate high-resolution digital elevation models to assess the flow of water and subsequent erosion from bare soil surfaces. This project will investigate if photogrammetry can be used to identify surface properties that can be used to assess surface susceptibility to soil erosion.
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Can laser refraction be used to assess soil structural stability?
Soil science has a myriad of methods to measure soil structural stability. Conventional methods range from, for example, wet and dry sieving, soil strength, various types of dispersion tests, and more engineering-type tests. Most of these tests apply energy to break up soil structure and then use crisp empirical data sets to assess the change in aggregation as a consequence of energy input. Sieving methods are limited by how many sieves are used and the crisp set always results in a very limited number of aggregate size fractions; the crisp data set of dispersion is almost binary data. The same applies to particle size distribution where particle distribution is simplified to a small number of size classes. In most cases only the three main classes; i.e. sand silt and clay. A relatively new method to measure a continuous particle size distribution by laser refraction. This method can potentially also be used to measure the stability of aggregate size distribution rather than a limited number of size classes by sieving to different mesh sizes. Only limited data exist where laser refraction has been used to assess soil structural stability.
The first part of this project aims to develop a robust methodology to assess aggregate size distribution stability using laser refraction, the 2nd part of the project is to assess the method’s ability to quantify aggregate size distribution stability on Ferrosols with different organic carbon contents. The project will use the laser refraction machine Malvern Mastersizer 2000 located at the St Lucia soil laboratories.
Supervision history
Completed supervision
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2018
Doctor Philosophy
Nitrogen and root zone temperature effects on sweetpotato cultivation on large mounds
Principal Advisor
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2014
Doctor Philosophy
Improving the capacity to represent surface runoff processes in rangeland biophysical models
Principal Advisor
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2024
Doctor Philosophy
An investigation into the chemical, physical and biological properties of manufactured soil produced from bauxite residue
Associate Advisor
Other advisors: Dr Ya-Feng Zhou, Dr Richard Haynes
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2016
Doctor Philosophy
The potential of Australian bermudagrasses (Cynodon spp.) for vegetating hostile soils
Associate Advisor
Other advisors: Emeritus Professor Shu Fukai, Dr Christopher Lambrides
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2014
Doctor Philosophy
The water and salt balance of a land disposal system for highly saline industrial effluent
Associate Advisor
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2013
Doctor Philosophy
Sources, mobility and fate of salts in soils of the Queensland Murray-Darling Basin
Associate Advisor
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2010
Doctor Philosophy
Subsoil constraints to root growth and water use efficiency in northern grain soils
Associate Advisor
Other advisors: Adjunct Professor Ram Dalal AM
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2010
Doctor Philosophy
Long-term productivity of Leucaena (Leucaena Leucocephala) - Grass pastures in Queensland
Associate Advisor
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2007
Doctor Philosophy
THE HYDROLOGY OF SEPTIC TANK - SOIL ABSORPTION SYSTEMS: INVESTIGATION AND PREDICTION OF HYDRAULIC FAILURE
Associate Advisor
Media
Enquiries
Contact Dr Gunnar Kirchhof directly for media enquiries about:
- Agro-ecosystems - tropical
- Conservation agriculture
- Papua New Guinea - farming
- Papua New Guinea - highland soil
- Soil - fertility decline
- Soil management
- Soil science
- Tropical and temperate regions - soil
- Urban water recycling
- Water management
- Water recycling
- Water utilities
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