Plant nutrition and soil fertility
Most of our research has concentrated on the physiology and function of micronutrient deficiencies, particularly boron, zinc and molybdenum, and their diagnosis and prediction in crops and soils. The plant nutrition and soil fertility programme in Western Australia currently focuses on GRDC-funded projects:
The plant nutrition and soil fertility programme is also an international endeavour with collaborative links in Bangladesh, Cambodia, China, Germany, Japan, Thailand, and the USA. Research Topics
Profitable and sustainable nutrient management in the WA grains industryGrains Research and Development Corporation (GRDC), the Department of Agriculture Western Australia (DAWA), the University of Western Australia (UWA) and Murdoch University (MU) are joint investors in a 3-year project with the following aims:
Fertiliser now represents about one-third of the variable costs of growing grain crops, with the average expenditure in WA being about $60,000 per farm per year. The pioneer phase of crop nutrition in the WA wheatbelt was largely complete by the 1980's. Correcting basic nutrient deficiencies dominated the research of that era. Fertiliser practices were developed primarily for wheat in rotations that included regular cultivation and extended periods of pasture. Many changes in WA's grainbelt have taken place since. Some changes are: high rates of application of some fertilisers have led to increasing soil reserves of these nutrients; exports of nutrients in grain (at an accelerating rate due to increasing yields) has not been matched by inputs, leading to deficiencies and other side-effects such as acidification; larger areas of more diverse crops are now sown (having replaced pasture), usually with minimal tillage; precision agriculture technology adds opportunities and complexity for nutrient management; more information sources have emerged, some with new (sometimes conflicting) ideas about nutrient management; and grower groups have become key players in R&D. Inadequate knowledge on soil fertility and plant nutrition is an impediment to further improvements in crop productivity, grain quality, farming system sustainability, and farm profits in WA. This has been exacerbated by a ten year period with reduced levels of R&D into the nutrient management in western region grain production systems. This project has been developed through a process of consultations with farmers, farm advisers, the fertiliser industry and researchers. The project will follow two lines of work, each addressed in its own module: firstly to develop a clear overview of the nutrient management issues to be dealt with in the medium- to long- term; and secondly to undertake innovative research into the opportunities coming from manipulating the distribution of nutrients throughout the rooting zone of plants. With changes in WA's farming systems and reduced emphasis on nutrient management research in recent times, it is important to review assumptions about important nutrient management issues. This module will provide a source of knowledge from which decisions can be made about future directions of RD&E into nutrient management in the Western Region. A short-list of key nutrient management issues will be developed with farmer groups, farm advisers, fertiliser companies and researchers. A priority of this module is to systematically assemble existing knowledge for the key issues, critically examine it for information that will assist growers and advisers and then work with WA nutrient management research workers to package it into position papers. The position papers will be drafted by a Post-doctoral Research Fellow working closely with Bell, Bolland, Bowden, Brennan, Porter and Rengel, then critically reviewed by a focus group of research workers and advisers and by other NMI projects. This detailed analysis will be synthesized into an overarching situation statement on nutrient management in the western grain region. |
 Normal wheat ear on the left side and ear showing failure of fertilisation on the right (wheat sterility). Photo: Professor Benjavan Rerkasem, Chiang Mai University. |
A project on "Causes of Wheat Sterility in sub-tropical Asia" was conducted collaboratively with CSIRO Division of Plant Industry, Chiang Mai University and scientists from Bangladesh, China, Nepal and Pakistan to find solutions to the puzzling phenomenon of sterility in sub-tropical wheat. This project was significant because it demonstrated that high vapour pressure deficit and low temperature depress boron uptake by wheat, and that these environmental conditions are able to induce sterility even when soil boron levels are not low. The period when wheat is susceptible to sterility can be quite short. Our paper in Annals of Botany describes this work (Huang et al. 1999). Critical stages of reproductive development in wheat are under investigation using histological and stable boron isotope techniques. Dr Longbin Huang visited the Unversity of Kyoto, Japan to collaborate with them on the use of polyclonal antibody techniques to identify sites of boron binding in cells walls of wheat floral organs. With Chiang Mai University, we have shown that B efficiency among wheat genotypes can be attributed to more efficient long distance transport of B into the ear after uptake by roots, probably involving xylem-to-phloem transfer in the stem. By contrast, there was little evidence of B retranslocation into the ears or of cultivar differences in this trait. These findings are reported in recent papers by Huang et al. (J. Exp Bot 2001) and NaChiangmai et al. Plant and Soil 2004).
The first International Symposium on Boron in Soils and Plants was held in Chiang Mai, 7-11 September 1997. This Symposium critically reviewed the state-of-the-art with boron research in soils and plants. Authors from 18 countries presented papers. The second International Symposium on Boron in Soils and Plants was held in Bonn (2001) and the third is planned for Wuhan, China in September 2005.
 Rainfed rice growing soils of Takeo, Cambodia. Photo: R.Bell |
From 1993, Dr Bell has collaborated with researchers in Cambodia on nutrient management for rice. Through this collaboration, three Cambodian staff have completed PhD degrees at Murdoch.
Phosphorus cycling in rainfed lowland rice ecosystems is poorly understood. Soil drying and grazing of rice straw during the long dry season, the growth of volunteer pastures during the early wet season, and intermittent loss of soil-water saturation while the rice crop is growing are important distinguishing characteristics of the rainfed lowlands in relation to P cycling. We studied P cycling in an acid sandy rainfed lowland soil that covers about 30 % of the rice growing area of Cambodia. Soils with similar
properties in comparable rainfed sub-ecosystems occur in Laos and northeast Thailand. We developed a general schema of P pools and fluxes in the crop and soil for rice-based cropping systems in the rainfed lowlands of Cambodia. The schema was derived from a number of field experiments carried out over five consecutive cropping seasons to quantify the residual value of P fertiliser, P mass balances, soil P fractions, the effect on subsequent rice crops of crop residues and volunteer pastures incorporated into the soils, and the dynamics of P turnover in the soil. With a single rice crop yielding 2.5-3 t ha-1, application of 8-10 kg P ha-1 maintained yields and a small positive balance in the soil. However, the soil P balance was sensitive to the proportion of rice straw returned to the soil. Volunteer pastures growing during the early wet season accumulated significant amounts of P, and increased their P uptake when soils were previously fertilised with P. These pastures recycled 3-10 kg P ha-1 for the succeeding rice crops. While inorganic soil P pools extractable with ion exchange resins and 0.1 M NaOH appeared to be the main source of P absorbed by rice, microbial and organically-bound P pools responded dynamically to variation in soil water regimes of the main wet, dry and early wet seasons. The schema needs to be developed further to incorporate site-specific conditions and management factors that directly or indirectly affect P cycling, especially loss of soil-water saturation during the rice cropping cycle. Our paper on this work which will appear in Plant and Soil (Pheav et al., 2005) also discusses the application of results on other significant rice soils in the rainfed lowlands of southeast Asia.
Adaption of rice roots to changing soil water regimes
In Asia, rice is the most important staple food but padi rice cultivation uses large volumes of fresh water. Rice has low water use efficiency due to losses by evaporation, leakage from the root zone and run-off. Water productivity in rice is three to four times lower than in all other cereals. Many national governments in Asia are concerned to reduce freshwater use in agriculture and in padi rice production in particular to free up water resources for other sectors. This has led to the initiation of research and development on water saving rice production systems over the last few years (Dittert et al., 2005). In China, the Ground Cover Rice Production System (GCRPS, also called Plastic Film Mulching) has been shown to use less water and decrease evaporative water loss from rice field compared to the flooded system traditionally used. However, in saving water rice, grain yield was up to 40 % lower than in traditional padi fields (Dittert et al., 2005). Clearly Asia countries cannot afford a significant drop in rice production even though they have a need to save water from rice fields for other purposes. In China and many other Asian countries, drop in rice yield would threaten food security. In rice exporting national like Thailand and Vietnam it would threaten economic growth and poverty alleviation by reducing incomes of the smallholder farmers. Closing the yield gap between water saving rice production systems and submerged rice cultivation is a key imperative for ensuring widespread adoption by farmers of the water saving production technologies.
Rice roots have evolved to absorb water and nutrients from the flooded padi soils. They may not be well adapted to efficiently absorb water and nutrients under fluctuating water regimes or in water limited soils (Bell et al., 2001). Indeed a major reason why rainfed rice yields in Asia has lagged behind those in irrigated padi fields is due to difficulties of the rainfed rice in water and nutrient acquisition (Wade et al., 1999a, b). Nutrient availability for rice is generally decreased when soils lose soil water saturation. Hence water saving rice may require increased fertilizers and expose roots to stresses such as aluminium toxicity that are absent in flooded padi fields. Rice roots are very shallow and this places rice at greater risk of drought than in most other crops (Wade et al., 1999a, b). Finally the adaptions of rice roots to flooded soils, including loss of cortical cells (called aerenchyma) and formation of a tight barrier to oxygen loss (Colmer, 2003) may not be ideal root characteristics for water saving production systems. We propose the need for a more thorough understanding of the function and adaptation of rice roots and of nutrient availability in wet soils to close the yield gap between traditional and saving water rice systems. Such understanding should focus on nutrient use and water use efficiency. The yield gap may result from among other causes, the poor morphological and physiological adaptation of rice roots to less water. The acquisition of more basic knowledge of rice root adaption and nutrient and water use efficiency will support the long term development of saving water rice production systems capable of closing the rice grain yield gap.
Current - Mr Suphasit Sitthaphanit - "Fertilizer strategies for sandy soils in a high rainfall regime"
Co-supervisors: Assoc Prof V. Limpinuntana, Prof R.W. Bell
Enrolled at Khon Kaen UniversityCurrent - Mr Nisit Kamla - "Using natural plant-based extracts as fertilisers and soil amendments for crop production in NE Thailand"
Co-supervisors: Dr V. Limpinuntana, Prof R.W. Bell
Enrolled at Khon Kaen UniversityCurrent - Mr Vuthipun Thongviang - "Soil constraints to soybean production on sandy soils in NE Thailand"
Co-supervisors: Dr V. Limpinuntana, Prof R.W. Bell
Enrolled at Khon Kaen UniversityCurrent - Ms Sutisa Pinitpaisoon - "Modelling the joint response of maize to compost and inorganic fertilizer"
Co-supervisors: Professor A Suwanarit, Prof R.W. Bell
Enrolled at Kasetsart UniversityCurrent - Ms Ingrid Krockenberger : "Effect of nitrogen status on water relations in blue gums"
Supervisors: Prof R.W.Bell, Dr D.White (CSIRO Forestry and Forest Products) and Assoc Prof B.Dell2006 - Dr Nednepa Insulad - "Root dynamics in rainfed rice and its implications for nitrogen uptake"
Co-supervisors: Prof B. Rerkasem, Assoc Prof R. Bell2004 - Dr Ross Brennan - "Zinc nutrition of plants"
2004 - Dr Ye Zhengqian - "Environmental factors affecting boron requirements of plants"
Supervisors: Assoc. Prof R.W.Bell, Assoc. Prof. B.Dell2003 - Dr Duangjai NaChiangmai - "Mechanisms of boron efficiency in wheat"
Supervisors: Professor B Rerkasem, Assoc Prof B. Dell
Awarded by Chiang Mai University
2003 - Dr Sovuthy Pheav - "Improving the efficiency of phosphorus use in lowland rainfed rice"
Supervisors: Assoc. Prof R.W.Bell, Dr P.White (Cambodia-IRRI-Australian Project) and Dr G.Kirk (IRRI, Philippines)2003 - Dr Mulyati - "Zinc requirements of transplanted crops"
Supervisors: Assoc. Prof R.W.Bell, Dr L. Huang2002 - Dr Ahmed Deria : "Wheat production and soil fertility levels under conventional and organic farming systems"
Supervisors: Assoc. Prof R.W.Bell, Dr G.W.O’Hara2000 - Dr Vang Seng - "Edaphic factors limiting lowland rainfed rice production in soils in southeast Cambodia"
Supervisors: Assoc. Prof R.W.Bell, Dr H.J.Nesbitt (Cambodia-IRRI-Australia Project) and Dr I. Willett (ACIAR)1999 - Dr Adil Asad - "External and internal boron requirements of plants"
Supervisors: Assoc. Prof R.W.Bell, Assoc. Prof. B.Dell1998 - Dr Ros Chhay - "Management of seedling nutrition in lowland rainfed rice"
Supervisors: Assoc. Prof R.W.Bell, Dr P.J.White (Cambodia-IRRI Rice project, Phnom Penh, Cambodia)1993 - Dr Somphob Jongruaysap - "Molybdenum nutrition of black gram (Vigna mungo (L.) Hepper)"
Supervisors: Dr B.Dell (Principal), Dr R.W.Bell.1991 - Dr Rojarae Netsangtip - "Boron nutrition of black gram (Vigna mungo (L.) Hepper)"
Supervisors: Professor J. Loneragan (Principal), Dr B.Dell, Dr. B.Rerkasem (Chiang Mai University), Dr R.W.Bell1989 - Dr Nantarat Supakamnerd - "Sulfur nutrition of peanut (Arachis hypogaea [L.])"
Supervisors: Dr B. Dell, Dr R.W.Bell
1992 - Mr Fred Chilufiya - "Nitrogen and phosphorus nutrition of kangaroo paw (Anigozanthos pulcherrimus Hooker)"
Supervisors: Dr R.W.Bell, Dr B.Dell (Principal Supervisor)1988 - Mr Sukum Chotechaungmanirat - "Diagnosis of molybdenum deficiency in soybean (Glycine max (L.) Merr.) by plant analysis"
Supervisors: Professor A.Robson (University of Western Australia) and Professor J.Loneragan, Dr R.W.Bell
1989 - Ms Lorraine McLay - "Diagnosis of molybdenum deficiency in green gram (Vigna radiata (L.) Wilczek) by plant analysis"
Co-supervisor: Professor J. Loneragan1986 - Ms Danielle Brady - "Diagnosis of potassium deficiency in peanut (Arachis hypogaea [L.]) by plant analysis"
Co-supervisors: Professor J. Loneragan, Dr B. Dell
Dr Bill Bowden, Department of Agriculture and Food, Northam
Dr Ross Brennan, Department of Agriculture and Food, Albany
Dr Tim Colmer, School of Plant Biology, University of Western Australia
Professor Bernie Dell, School of Biological Sciences and Biotechnology >> more
Dr Longbin Huang, School of Land and Food, University of Queensland
Professor Zed Rengel, University of Western Australia
Dr Ian Willett, ACIAR, Canberra
Dr Don White, CSIRO Forestry and Forest Products, Floreat Park
Dr Peter White, Department of Agriculture and Food, S. Perth
Dr Mike Wong, CSIRO Land and Water, Floreat Park
Noel Schoknecht, Department of Agriculture and Food, S. Perth
International Research
Professor Benjavan Rerkasem, Chiang Mai University , Thailand
Professor Amnat Suwanarit, Kasetsart University, Thailand
Associate Professor Viriya Limpintunana, Khon Kaen University, Thailand
Professor Achim Dobermann, University of Nebraska, USA
Professor Yang Xiaoe, Zhejiang University, Hangzhou, China
Professor Ye Zhengqian, Zhejiang Forestry University, China
Professor Patrick Brown, University of California-Davis, USA
Associate Professor Toru Matoh, University of Kyoto, Japan
Professor T Yamaguchi, Chiba Institute, Chiba, Japan
Dr Simon Cook, IMWI, Colombo, Sri Lanka
Dr Vang Seng, Team Leader, Office of Soil and Water, Cambodian Agricultural Research and Development Institute, Phnom Penh, Cambodia
Professor Heiner Goldbach, University of Bonn, Germany
Prof Guy Kirk, Cranfield University, UK
Centre for Organic Waste Management
UWA Soil Science and Plant Nutrition
Dept of Pomology, University of California-Davis
School of Land and Food, University of Queensland
Department of Plant Science, Waite Agricultural Research Institute
Hohenheim University, Stuttgart
Chiang Mai University, Department of Agronomy
Grain Research and Development Corporation
| Document
author: R.Bell;
created: 16/06/03, updated:
11/06/07
, expiry: 01/01/08 Document edited by: H.Gordon School of Environmental Science, Murdoch University, South St, Murdoch, Western Australia, 6150 Ph (08) 9360 2488 Fax: (08) 9310 4997 www.environment.murdoch.edu.au Disclaimer & Copyright Notice @ Murdoch University Registered Provider Code: 00125J |
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