Posts in Soils
Improving rice water use efficiency - Direct Drilling of rice and Precision Farming (June 2014)


Water use efficiency is a driving factor for the Australian rice industry. Australian rice farmers grow rice in one of the driest continents in the world, achieving some of the world’s highest yields per hectare and water use efficiency per kilogram produced (Dunn & Pal Singh, 2013). In recent years, the availability of water for agricultural production has been reduced significantly as a result of government policy. Australian rice farmers are also under constant scrutiny to justify their water usage, so need to develop new technologies and practices. Historically Australia is one of the few countries to establish a rice crop by flying rice seed into a flooded bay. The majority of the countries visited establish their crops by drilling seed into the soil and establish by flushing. In Australia, this technique could be more broadly adopted with significant savings in water use and input costs.

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Straighthead in Australian rice crops (May 2014)

Straighthead is a ‘physiological’ disorder of rice which causes floret sterility and reduced grain yield. The symptoms are only obvious at panicle emergence and it is often confused with cold induced sterility, particularly in less severe cases.
Although there is no known cause of straighthead it is thought to be related to soil conditions induced by permanent flooding. It is not seed borne or transmitted around the farm.

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Managing rice snails with copper sulphate - RIRDC Project PRJ - 005685 (2013)


Snails in rice crops are becoming a more significant problem for growers because of increased levels of repeat cropping aimed at maximising water use efficiency. Repeat cropping allows dormant snails to survive in the soil. Research on copper sulphate aimed at gaining product registration and ensuring its ongoing availability for snail control has shown that its variable performance relates strongly to soil type. Higher application rates are needed to the water above soils rich in dissolved organic carbon.  Even above soils low in dissolved organic carbon, biologically active copper concentrations fall dramatically within an hour of application.  Although soil testing could allow copper application rates to be ‘fine-tuned’ for individual fields, finding alternative chemicals unaffected by soil type should be a higher priority.

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Approaches to Managing Variability of Rice Growth and Yield- Link (March 2013)

This RIRDC report is aimed at rice growers, commercial and public advisory agronomists, rice researchers, irrigation surveyors and designers, and landforming operators in rice growing areas. The report outlines investigations into the causes of in-field variability of rice crop growth, yield and management options for improving the poor yielding areas. The project consisted of three main objectives including firstly identify and understand factors contributing to in-field spatial variability in rice yield. Secondly identify and evaluate methods by which rice growers can manage in-field spatial variability in yield to increase production, profitability and water productivity and thirdly to maintain the NIR calibrations and instruments for the rice NIR Tissue Testing Service and update the associated PI nitrogen topdressing recommendations. The project was undertaken using replicated field experiments which were located in multiple rice growers’ fields in areas of both natural soil (no cut or fill) and subsoil surfaces which had been exposed by laser levelling operations. Soil treatments consisted of both chemical fertiliser (with varying major and minor nutrients) and organic fertilisers (chicken litter and feedlot manure). Rice establishment, growth and yield were monitored and measured. Generally three sets of field experiments were implemented each season. In conjunction with this experiment each year of the project there were complementary extensive large pot experiments undertaken in a polyhouse at Yanco Agricultural Institute The research identified that most of the in-field variability in rice growth and yield variability could be attributed to poor growth and low yield being obtained on exposed sub-soil surfaces due to macro and micro nutrient deficiencies and interactions. Significant increase in rice crop growth and yield were obtained by applications of high rates of nitrogen and phosphorus fertilisers to exposed subsoils. Rice crop growth and yield responses were also were found on red brown earth soils with the application of zinc, either in the fertiliser mix sown with the seed or as a seed coat. The researchers believe that targeted applications (based on soil tests) of phosphorus and zinc, along with good pre-permanent water and PI nitrogen management will increase yields in exposed subsoil areas of rice fields. This will decrease in-field rice yield variability resulting in increased rice production and water productivity across the industry and provide flow-on economic benefits to regional communities.

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New weed management options for Australian rice - RIRDC Project AGR-9A (2008)

Not sowing rice may be a valid herbicide resistance strategy but it is clearly not a preferred pathway for 1600 Riverina rice farmers who remain frustrated with a productive farming system, a strong market for their crop, an innovative processing company, but no water to produce their crop! With long lead times to attain a registered herbicide in rice, our research program for weed control is focussed ahead for the times when irrigation water is once again available.  With long lead times to attain a registered herbicide in rice, our research program for weed control is focussed ahead for the times when irrigation water is once again available.   As a result of contacts made in Japan and the USA during and prior to 2006, four herbicide candidates were field tested in Australia during the 2006–07 summer.  Two experimental herbicides have been identified, one for grass weed control and another for broadleaf and sedge weeds, both of which potentially present new modes of action.

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Timing of nitrogen applications for rice (2008)

This IREC farmers newsletter article presents a summary of five years of experiments investigating a suite of timings for nitrogen fertiliser application. Results indicate no significant differences in nitrogen responses among Australian rice varieties and optimum nitrogen requirement lies around 170–180 kg N/ha depending on the inherent soil nitrogen supply . Five years worth of results show that the best yields are obtained when nitrogen application is split between pre-flood and panicle initiation applications. A minimum pre-flood application of 90 kg N/ha in continuously cultivated bays is recommended to ensure adequate nitrogen supply during the vegetative growth stage of the crop to produce sufficient biomass to sustain a good yield. A maintenance requirement of nitrogen at panicle initiation is recommended to ensure adequate nitrogen supply to the plant during the reproductive stages. Mid-tillering nitrogen applications are warranted if an inadequate amount of pre-flood nitrogen was applied, early nitrogen application was not managed correctly, or the soil is inherently low in fertility

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Primefact: Rice production using groundwater (September 2007)

This Primefact sheets covers the use of ground water usage on rice. The sheet indicates the effects of water quality on rice production. It covers areas such as salinity effects on plants, effects of salinity on different rice varieties, water management plans, monitoring water quality and the impact of water quality on infiltration.

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The Happy Seeder enables direct drilling of wheat into rice stubble (January 2007)

This journal article present the results of the Happy seeder direct drilling wheat into rice stubble. The Happy seeder aims to reduce the need to burn rice stubble and in Australia and South East Asia. The focus of the Happy seeder is to enable direct drilling into tough dense rice stubble which is currently an obstruction to sowing into rice stubble. The article states that loss of organic matter and nutrients, rice stubble burning causes very serious and widespread air pollution in the north-west Indo-Gangetic Plains, where rice–wheat systems predominate. The Happy Seeder combines the stubble mulching and seed drilling functions in the one machine. The stubble is cut and picked up in front of the sowing tynes, which engage bare soil, and deposited behind the seed drill as mulch. This article presents the  evaluation of the technology over 3 years in replicated experiments and farmers’ fields in Punjab, India. 

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Can irrigation be sustainable - Link (2006)

This journal article discusses the issues associated with salinisation in irrigation areas.  This paper applies a whole of system-water balance to compare irrigation in three semi-arid regions suffering from similar sustainability issues: Rechna Doab (RD), Pakistan; the Liuyuankou irrigation system (LIS), China; and Murrumbidgee irrigation area (MIA), Australia. The major issues seen in these areas are soil salinity, water resources and ground water management. Data used to compare these different regions were climate and soils, available water and components of water balance. The project also examined the history of water resource development in each region. The paper concludes with these systems are dependent on direct or indirect use of groundwater. It compares the results from each region and the possible acceleration rate of salininsation. The paper expresses the need to quantify regional-water quality trends, downstream environmental impacts and the trade-off between yield reduction and direct regional groundwater use by crops in these systems. It also believes a need to radically rethink sustainability of food production, rational pricing and sharing of water and commodities. Thus justifying investment that will maintain and enhance ecosystem function within irrigated catchments. As the paper states that under present operational conditions, none of the three systems discussed in this paper is sustainable. 

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Direct drilling into stubbles with the Happy Seed (2006)

The Happy Seeder technology offers a solution to the problem of direct drilling into heavy stubbles, enabling the stubble to be retained on the surface as a mulch.  The rapid development of the technology, from concept to commercial reality in four years, has resulted from synergies between Australian and Indian engineers and scientists.  The Happy Seeder technology needs to be evaluated for a wide range of cropping systems – after one season's testing in Australia, it is thought that the Turbo Happy Seeder may be more appropriate for heavy rice stubbles.

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Using Raised Beds on Rice Farms - sustainable cropping systems on rice farms- Link (2006)

This RIRD report presents the results of the project using raised beds on rice farms - sustainable cropping systems on rice farms. The project was an experiment evaluating a new irrigation layout for rice and other crops. The targeted audience included rice and grain growers within rice based farming systems, advisory and commercial agronomists, irrigation surveyors and designers, irrigation distribution companies and, land and water management plan implementers operating in these areas. The project aim was to increase the sustainability, resource use efficiency, yield and profitability of rice-based cropping systems through improved soil, water and nutrient management using permanent raised bed systems. The method undertaken was a large replicated field experiment conducted at Coleambally Demonstration Farm, NSW. Double cropping with side-by-side demonstration of permanent raised beds (including sub surface drip irrigation) and traditional ‘flat’ layouts were investigated. Three broad types of crop sequence were selected to include both traditional and novel crop sequences (double cropping with both winter and summer crops each year). Different crop options were included within each broad sequence. In addition to this experiment the project estimated the potential benefits and costs involved in switching over to permanent raised beds over common irrigation layouts of rice based farming systems within a benefit cost framework. The key findings demonstrated that where irrigation supplies are sufficient rice can be grown in close rotation with winter cereals and other summer crops on raised beds. This demonstrated that the adoption of raised beds in terraced, bankless channel layouts provides an opportunity for this to occur. Barley/soybean double cropping was successful on raised beds in rotation with rice.  With the technology available it is viable from a financial perspective and as seen in the benefit cost analysis revealed that there are significant benefits in switching to permanent raised beds in terraced, bankless channel layouts.

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Straighthead in Australian rice crops (2006)

This IREC Farmers Newsletter focuses on the Straighthead that is estimated to loose the rice industry in excess of $1 million a year in yield loss. The symptoms and consequences of straight head include the  distortion of panicles and florets with the end result of sterility, which equates to yield loss. It generally occurs where stubble is incorporated and some varieties are more susceptible or tolerant to straight head than others. Further studies are required to understand the cause of the problem. This report presents the Australian studies to date and the effects varietal types, mid season draining, organic matter reduction, nitrogen rate effects, micronutrient effects on straight head, the development of a safer method  to induce straight head and soil redox potential. 

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Growing rice with less water (2006)

The Australian rice industry is a world leader in yields, quality and marketing. Water supply is fast becoming its greatest limitation. Can we find a rice growing system that will grow more rice per megalitre?  This Nuffield study overviewed work in several countries that is attempting to adopt aerobic and alternate-wet-and-dry (AWD) rice systems to increase water use efficiency.  The application of such systems in Australian rice growing has potential to lead to a 15–30% increase in water use efficiency, from evaporation savings.  Success of aerobic or AWD systems in Australia would require the rice industry to assess and adopt aerobic germplasm, refine AWD nitrogen management, consider Clearfield™ technology for broadleaf weed control and redefine rice soil suitability for AWD systems

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Rice microspore culture: a fast track to new varieties (2006)

This IREC Farmer newsletter report on progress of rice microspore culture to fast track new varieties. The current conventional plant breeding methods takes 8-10 generations. By using the method of anther and or microspore culture techniques this can be reduced to just 12-18 months. The method is undertaken by uses immature pollen grains or microspores that contain one set of chromosomes known as haploids. These can be grown on a specialised culture medium and induced to divided and double the chromosomes therefore developing two sets of chromosomes that become double haploids. By establishing a microspore culture system at Yanco it would allow the breeders to develop varieties faster as there would be direct access to doubled-haploids

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Integrated approaches to increasing water productivity in rice based systems in south east Australia. (May 2006)

Australian rice growers are under considerable pressure to increase water use efficiency to remain profitable and avoid soil salinisation. In particular, profitability is threatened by decreasing water availability and certainty of supply and by increasing water price, as a result of environmental and National Competition Policy agendas. Field irrigation water productivity has more than doubled in the past 20 years from an average of around 0.34 g paddy rice per kg water to around 0.77 g kg À1 , largely due to increased yield from the development and adoption of improved varieties and management strategies, and to a lesser degree due to the introduction of rice water use and soil suitability policies. Future increases in rice field water productivity will come from greater yields through breeding for increased cold tolerance, precision agriculture and improved crop establishment, and from reduced water use due to reduced duration of ponding. A key challenge of the next decade will be to increase cold tolerance to the extent that deep water ponding for low temperature protection is no longer required, possibly allowing a complete shift away from ponded culture and reducing irrigation water requirement. While increasing the water productivity of rice is important, water productivity and profitability of the entire cropping system is of ultimate importance. Growing winter crops after rice and permanent bed systems offer potential benefits of increased productivity of crops traditionally grown in rotation with rice and increased cropping diversity and flexibility. Irrigation water productivity is also being improved through on-farm and regional technologies such as on-farm recycling systems and automatic data acquisition and control systems in irrigation supply systems. To increase water use efficiency and achieve sustainability of rice-based farming systems in Australia, irrigation communities are implementing a range of on-farm and regional technologies and policies. An integrated approach is required to evaluate options, prioritise investments, maximise economic returns, guide policy and balance the environmental demands of river ecosystems with the needs of irrigated agriculture and its dependent regional communities. Significant progress is being made, through the development and application of farm and irrigation area hydrologic models linked with production models and economics, combined with strong stakeholder participation. The progress in integrating science, people and policy makers was recognised in 2002 by the award of the first ''Reference'' catchment status to the lower Murrumbidgee catchment, a major Australian rice-growing region, under the UNESCO/WMO HELP (Hydrology for Environment, Life and Policy) program. # 2005 Elsevier B.V. All rights reserved.
Integration of approaches to increasing water use efficiency.... Available from: https://www.researchgate.net/publication/228346350_Integration_of_approaches_to_increasing_water_use_efficiency_in_rice-based_systems_in_southeast_Australia [accessed May 08 2018].

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Effect of Rice Stubble Burning on Soil Health - Link (February 2006)


This RIRDC report present the findings of the investigation comparing the effects of stubble burning and stubble retention on a range of soil chemical and biological properties. The method  included comparing paired sites on eight properties, four pairs, with different histories and soil types in the Murrumbidgee Irrigation Area. The chemical properties included total soil carbon, nitrogen, phosphorus and sulphur (C, N, P and S). Soil biological properties included the size and activity of the microbial biomass, the microbial and metabolic quotients, the rate of cellulose decomposition and a range of information concerning the composition of the microbial population derived from fatty acid methyl ester (FAME) analysis. The findings included sites retaining stubble had significantly more C, N, P and S than the corresponding property that burnt stubble despite differences in other management strategies. It is considered that the biological properties of the stubble retained soils healthier than the corresponding stubble burnt soils. Whilst  two measurements used to indicate soil stress, the microbial quotient and a stress indicator derived from FAME analysis, indicate that the stubble retained soils were less stressed than the stubble burnt soils. The findings supported the view that for rice, or other summer crop stubble, to decompose at the fastest rate in the field it should be incorporated as soon as possible after harvest, before winter, and not during the sowing of the following summer crop, before summer. It is suggested that there needs to be a balance of available nutrients to optimise nutrient availability and potential carbon sequestration in stubble retained systems, especially in the early years after switching from a stubble burning regime. 

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