Letteratura scientifica selezionata sul tema "Crop rotation (Australia)"
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Articoli di riviste sul tema "Crop rotation (Australia)"
1
Norton, MR, R. Murison, ICR Holford e GG Robinson. "Rotation effects on sustainability of crop production: the Glen Innes rotation experiment". Australian Journal of Experimental Agriculture 35, n. 7 (1995): 893. http://dx.doi.org/10.1071/ea9950893.
Testo completoAbstract (sommario):
This study, which commenced in 1921, is the longest running crop rotation experiment in the summer rainfall region of Australia. The 7 rotation treatments comprise various frequencies and combinations of maize and spring oat crops with and without autumn oats and red clover ley. The maize and oat yields are analysed separately using principles described by Paterson (1964). Spline regressions are used to describe the trends of yields with time and to make comparisons amongst the rotations. Yield performance of maize and oats was improved as legume ley duration increased, although as maize cropping became more frequent this effect was reduced. Autumn-sown oats benefited both maize and spring oat yields, independent of the presence of a legume ley. Crop yields were generally maintained in those rotations containing a grazed clover ley. After alteration of ley management in the mid 1960s so that clover crops were subsequently removed as hay, crop yields in these rotations declined. The benefits of clover ley to crop productivity were considered to be primarily due to the maintenance of those soil chemical, physical, and biological properties associated with sustainable crop production.
2
Bhathal, J. S., e R. Loughman. "Ability of retained stubble to carry-over leaf diseases of wheat in rotation crops". Australian Journal of Experimental Agriculture 41, n. 5 (2001): 649. http://dx.doi.org/10.1071/ea00134.
Testo completoAbstract (sommario):
Increasingly, wheat rotations on sand-plain soils in Western Australia are being managed with stubble retention practices for reasons of moisture and soil conservation. A major concern in stubble retention practices is an associated increase in risk from septoria nodorum blotch (Phaeosphaeria nodorum) and yellow spot (Pyrenophora tritici-repentis). These pathogens frequently occur together in the region and survive in crop surface residues. The amount of disease carry-over on stubble is an important determinant of the severity of leaf diseases during the entire crop season. To provide a rationale for wheat leaf disease management in stubble retention rotation systems the extent to which retained wheat stubble induces disease in rotated crops was investigated. The frequency with which wheat stubble, which had been retained through a 1-year rotation, induced significant disease in seedling wheat was low (14%) over the 4-year period of study. While disease carry-over from wheat stubble retention in rotations is possible, it appears to be uncommon. The small proportion (1–8%) of retained wheat stubble that remained after germination of the return wheat crop in typical Western Australian farming systems further indicates that in general retained wheat stubble is not a significant source of disease carry-over in rotation wheat crops in this environment.
3
Schultz, JE. "Crop production in a rotation trial at Tarlee, South Australia". Australian Journal of Experimental Agriculture 35, n. 7 (1995): 865. http://dx.doi.org/10.1071/ea9950865.
Testo completoAbstract (sommario):
A crop rotation trial was established in 1977 on a hard-setting red-brown earth at Tarlee, South Australia, to monitor the long-term effect of intensive and traditional rotations on soil properties and crop production. The rotations involve wheat alternating with cereals, grain legumes, pasture, and fallow. There are 3 stubble + tillage treatments: remove stubble + cultivate, retain stubble + cultivate, retain stubble + no tillage. Three rates of nitrogen (0,40, 80 kg N/ha as ammonium nitrate) are applied to the wheat. Grain yield varied with seasonal conditions, and water use efficiencies were up to 10 kg/ha. mm. In the more productive rotations, wheat grain yields expressed as a percentage of potential yield tended to increase over time. The best wheat yields were always in rotations that included a grain legume or legume pasture, with additional yield increases in all rotations coming from the use of N fertiliser. By comparison with rotation and N fertiliser effects, there was little effect of the stubble + tillage treatments on grain yield. Most of the yield variations were related to differences in tiller density or grains per ear, with grain weight remaining relatively constant over all seasons. There was a tendency for grain legume yields to decrease over the latter years of the trial, and this was attributed to the build-up of plant diseases through growing the same species on the same plot every second year. Overall, faba beans were the highest yielding grain legume, and the wheat-beans rotation, with 80 kg N/ha on the wheat, gave highest total grain production. Data for residue remaining after harvest indicate that in some years there is less than the desired minimum levels to give adequate protection against erosion, so any grazing of the residues must be carefully managed.
4
Ewing, MA, AD Bathgate, RJ French e CK Revell. "The role of crop and pasture legumes in rotations on duplex soils". Australian Journal of Experimental Agriculture 32, n. 7 (1992): 971. http://dx.doi.org/10.1071/ea9920971.
Testo completoAbstract (sommario):
Duplex soils are prominent in southern Australia and are generally low in fertility. Their agricultural performance is, therefore, suboptimal in most circumstances without an exogenous source of nitrogen. This is often supplied by legumes which are grown in rotation with non-leguminous crops. Both crop and pasture legumes are now widely used in southern Australia and the contribution that they make to the non-legume phase of rotations is through nitrogen fixation and through other mechanisms such as cereal disease breaks. We use a mathematical programming model, MIDAS (Model of an Integrated Farming Dryland Agricultural System), to investigate the role of legumes in the low rainfall wheatbelt of Western Australia. The impact of legumes on farm profitability is assessed with a special focus on the contribution of legumes grown on a duplex soil. By using the model, the sensitivity of rotation choice on this duplex soil to changes in biological and economic parameters is explored. We conclude that crop legumes, in particular, have a firmly established role on sandy-surfaced duplex soils in low rainfall regions and that substantial increases in both the productivity and legume content of pasture would be required to outperform rotations which include crop legumes.
5
Turner, NC. "Crop production on duplex soils: an introduction". Australian Journal of Experimental Agriculture 32, n. 7 (1992): 797. http://dx.doi.org/10.1071/ea9920797.
Testo completoAbstract (sommario):
Duplex or texture-contrast soils occur over about 60% of the agricultural areas of south-west Western Australia. Annual crops of wheat, barley, oats, and lupins predominate on these soils, grown in rotation with annual pastures. The climate is characterised by cool, wet winters and hot, dry summers. Crop production is restricted to the winter and spring and is limited by waterlogging in the wet winter months and by water shortage during grain filling in spring. Research on crop production on duplex soils has been undertaken for the past 8 years by a collaborative team from the CSIRO Dryland Crops andyoils Program and the Western Australian Department of Agriculture. This research has been focussed on 3 sites at which processes limiting crop production on duplex soils have been highlighted. This special issue was initiated to summarise that research and to put it in its regional and national perspective. Additionally, opportunity was taken to compare and contrast experiences both within Western Australia and throughout Australia, and to draw out management options for crop production on duplex soils.
6
Bell, Lindsay W., Andrew T. James, Mary Ann Augustin, Artur Rombenso, David Blyth, Cedric Simon, Thomas J. V. Higgins e Jose M. Barrero. "A Niche for Cowpea in Sub-Tropical Australia?" Agronomy 11, n. 8 (19 agosto 2021): 1654. http://dx.doi.org/10.3390/agronomy11081654.
Testo completoAbstract (sommario):
Pulses have emerged as important rotation crops in Australia. Some are in demand in agricultural production systems due to their high potential market value, because of their roles as grain or forage crops, their nitrogen fixation capability, and because they provide a disease break or improve soil health. While several pulse crops have been identified for winter-season cropping, there are few adapted legumes apart from mungbean that are appropriate for dryland summer cropping. Currently, short-duration crops of mungbean are commonly used, but yields are highly variable and susceptible to drought. Here, we propose that cowpea has the potential to become an alternative rotation crop in dryland summer cropping zones, providing a competitive and profitable alternative pulse crop option where its drought tolerance could enable better performance under inconsistent in-crop rainfall. We demonstrate that cowpea has nutritional properties and putative uses that could prove valuable in emerging plant-based protein and aquaculture markets.
7
Hulugalle, N. R., e F. Scott. "A review of the changes in soil quality and profitability accomplished by sowing rotation crops after cotton in Australian Vertosols from 1970 to 2006". Soil Research 46, n. 2 (2008): 173. http://dx.doi.org/10.1071/sr07077.
Testo completoAbstract (sommario):
In agricultural systems, soil quality is thought of in terms of productive land that can maintain or increase farm profitability, as well as conserving soil resources so that future farming generations can make a living. Management practices which can modify soil quality include tillage systems and crop rotations. A major proportion of Australian cotton (Gossypium hirsutum L.) is grown on Vertosols (~75%), of which almost 80% is irrigated. These soils have high clay contents (40–80 g/100 g) and strong shrink–swell capacities, but are frequently sodic at depth and prone to deterioration in soil physical quality if incorrectly managed. Due to extensive yield losses caused by widespread deterioration of soil structure and declining fertility associated with tillage, trafficking, and picking under wet conditions during the middle and late 1970s, a major research program was initiated with the objective of developing soil management systems which could improve cotton yields while concurrently ameliorating and maintaining soil structure and fertility. An outcome of this research was the identification of cotton–winter crop sequences sown in a 1 : 1 rotation as being able to sustain lint yields while at the same time maintaining soil physical quality and minimising fertility decline. Consequently, today, a large proportion (~75%) of Australian cotton is grown in rotation with winter cereals such as wheat (Triticum aestivum L.), or legumes such as faba bean (Vicia faba L.). A second phase of research on cotton rotations in Vertosols was initiated during the early 1990s with the main objective of identifying sustainable cotton–rotation crop sequences; viz. crop sequences which maintained and improved soil quality, minimised disease incidence, facilitated soil organic carbon sequestration, and maximised economic returns and cotton water use efficiency in the major commercial cotton-growing regions of Australia. The objective of this review was to summarise the key findings of both these phases of Australian research with respect to soil quality and profitability, and identify future areas of for research. Wheat rotation crops under irrigated and dryland conditions and in a range of climates where cotton is grown can improve soil quality indicators such as subsoil structure, salinity, and sodicity under irrigated and dryland conditions, while leguminous crops can increase available nitrogen by fixing atmospheric nitrogen, and by reducing N volatilisation and leaching losses. Soil organic carbon in most locations has decreased with time, although the rate of decrease may be reduced by sowing crop sequences that return about 2 kg/m2.crop cycle of residues to the soil, minimising tillage and optimising N inputs. Although the beneficial effects of soil biodiversity on quality of soil are claimed to be many, except for a few studies on soil macrofauna such as ants, conclusive field-based evidence to demonstrate this has not been forthcoming with respect to cotton rotations. In general, lowest average lint yields per hectare were with cotton monoculture. The cotton–wheat systems generally returned higher average gross margins/ML irrigation water than cotton monoculture and other rotation crops. This indicates that where irrigation water, rather than land, is the limiting resource, cotton–wheat systems would be more profitable. Recently, the addition of vetch (Vicia villosa Roth.) to the cotton–wheat system has further improved average cotton yields and profitability. Profitability of cotton–wheat sequences varies with the relative price of cotton to wheat. In comparison with cotton monoculture, cotton–rotation crop sequences may be more resilient to price increases in fuel and fertiliser due to lower overall input costs. The profitability of cotton–rotation crop sequences such as cotton–wheat, where cotton is not sown in the same field every year, is more resilient to fluctuations in the price of cotton lint, fuel and nitrogen fertiliser. This review identified several issues with respect to cotton–rotation crop sequences where knowledge is lacking or very limited. These are: research into ‘new’ crop rotations; comparative soil quality effects of managing rotation crop stubble; machinery attachments for managing rotation crop stubble in situ in permanent bed systems; the minimum amount of crop stubble which needs to be returned per cropping cycle to increase SOC levels from present values; the relative efficacy of C3 and C4 rotation crops in relation to carbon sequestration; the interactions between soil biodiversity and soil physical and chemical quality indicators, and cotton yields; and the effects of sowing rotation crops after cotton on farm and cotton industry economic indicators such as the economic incentives for adopting new cotton rotations, farm level impacts of research and extension investments, and industry- and community/catchment-wide economic modelling of the impact of cotton research and extension activities.
8
Cox, H. W., R. M. Kelly e W. M. Strong. "Pulse crops in rotation with cereals can be a profitable alternative to nitrogen fertiliser in central Queensland". Crop and Pasture Science 61, n. 9 (2010): 752. http://dx.doi.org/10.1071/cp09352.
Testo completoAbstract (sommario):
Empirical and simulation results from three crop rotations incorporating cereals, pulses and nitrogen (N) fertiliser application were examined over 4 years in a subtropical environment, central Queensland, Australia. The hypothesis was that pulse crops in rotation with cereals would be a viable alternative to applying N fertilisers and would improve farm business economic performance provided the yield potential of pulses were not compromised by planting into very low soil water situations. Empirical data and simulations with the Agricultural Production Systems Simulator model were used to give insights into the N contribution, yield benefit to cereals and overall economic performance of the inclusion of pulses into the rotation. The field trial rotations included: rotation 1: sorghum and wheat in an opportunity crop rotation (called cereals-only), rotation 2; cereals grown following a fallow with a pulse crop immediately after (called cereal double-cropped pulse) and rotation 3, pulses grown following a fallow with a cereal crop immediately after (called pulse double-cropped cereal). Empirical and simulated results indicated that the cereal double-cropped pulse rotation produced the highest average annual gross margins using prices at that time. In the simulations, when pulse crops were included in the rotation, no additional N fertiliser was required and the lowest chance of negative gross margins was obtained. The cereal double-cropped pulse rotation produced the largest trial and simulated gross margins. The pulse double-cropped cereal rotation produced greater gross margins than the N-deficient cereals-only rotation but significantly lower than the cereal double-cropped pulse rotation. Simulations indicated that the cereals-only rotation could be made profitable when the soil was ‘topped-up’ to 100 kg available N/ha before planting, or by 40 kg N/ha to each cereal crop. Chickpea and mungbean contributed an average of 35 and 29 kg N/ha, respectively, in the field trial. A minimum of 100 mm of the stored soil water at planting was needed to reduce the risk of negative returns. By planting only when the soil contained adequate water, the cereal double-cropped pulse rotation may provide a valuable supplement to farm income while simultaneously reducing the need for N fertilisers on the cereals. Alternatively, in a rotation with cereals only, modest amounts of fertiliser N will maintain profitability with minimal levels of financial risk.
9
Lawes, Roger, e Michael Renton. "The Land Use Sequence Optimiser (LUSO): A theoretical framework for analysing crop sequences in response to nitrogen, disease and weed populations". Crop and Pasture Science 61, n. 10 (2010): 835. http://dx.doi.org/10.1071/cp10026.
Testo completoAbstract (sommario):
The break crop effect, where a non-cereal crop provides relief from soil pathogens, may increase soil nitrogen reserves for a cereal and help minimise populations of herbicide resistant weeds. It is widely used in agriculture to maximise the economic return and yield of cereal crops. In Western Australia, cereal crops are being grown with increasing frequency, at the expense of less profitable break crops and we have developed a land use sequence optimiser (LUSO) to analyse strategic break crop decisions across a suite of price, yield, nitrogen fertiliser cost, soil borne disease load and weed load thresholds. The model is flexible and can easily be parameterised for a wide range of economic, edaphic and biotic parameters. We demonstrate its use in a strategic sense to determine economic and biotic thresholds that force a rotation change in a typical Western Australian cropping system.
10
Hulugalle, Nilantha R., Bruce McCorkell, Viliami F. Heimoana e Lloyd A. Finlay. "SHORT COMMUNICATION: Soil Properties Under Cotton-Corn Rotations in Australian Cotton Farms". Journal of Cotton Science 20, n. 4 (2016): 294–98. http://dx.doi.org/10.56454/fsng2773.
Testo completoAbstract (sommario):
During the past decade sowing corn (Zea mays L.) in rotation with cotton (Gossypium hirsutum L.) has gained popularity among many Australian cotton growers. Research on cotton-corn rotations in Australia is sparse, although anecdotal evidence suggests that subsequent cotton yields are increased. Our objective was to quantify the impact of sowing a corn rotation crop on soil properties of Vertisols under cotton-based farming systems on 18 farms within Australian cotton-growing regions. Each site had either corn or cotton sown during the preceding summer. Soil was sampled in transects from the surface 0.3 m. Soil organic carbon concentrations and storage were higher, and exchangeable cation concentrations lower after corn than after cotton but soil structure was not significantly affected. The yield increases reported by cotton growers are, therefore, unlikely to have been caused by the soil properties measured in this study. Enhanced cycling of nutrients such as N and P through higher soil organic matter and microbial activity cannot, however, be ruled out.
Tesi sul tema "Crop rotation (Australia)"
1
Christodoulou, Nicholas, of Western Sydney Hawkesbury University e Faculty of Environmental Management and Agriculture. "Learning to develop participative processes to improve farming systems in the Balonne Shire, Queensland". THESIS_FEMA_XXX_Christodoulou_N.xml, 2000. http://handle.uws.edu.au:8081/1959.7/302.
Testo completoAbstract (sommario):
This thesis develops two related themes.The first is that participatory approaches to agricultural research and extension can provide a sound process for all stakeholders to learn how to develop more sustainable agriculture. The second is that appropriate levels of participation can be used to link knowledge from three important sources: local knowledge, scientific knowledge and experiential knowledge.The thesis develops these two related themes by examining the inconsistencies between esposed theories of participatory approaches (i.e.intended behaviour) and theories in action (i.e. what is actually practised).The study was based upon the work of a major research, development and extension (R, D and E)project known as the Western Farming Systems Project (WSFP),which was concerned with the development of sustainable rotations and cropping practices in south western Queensland and north western N.S.W. between 1994-1999. The study was conducted in the Balonne Shire, centred on the town of St. George, Queensland, Australia.Master of Science (Hons)
2
McLaughlin, Michael John. "Phosphorus cycling in soil under wheat-pasture rotations /". Title page, contents and summary only, 1986. http://web4.library.adelaide.edu.au/theses/09PH/09phm1615.pdf.
Testo completo
3
Doole, Graeme John. "Value of perennial pasture phases in dryland agricultural systems of the eastern-central wheat belt of Western Australia". University of Western Australia. School of Agricultural and Resource Economics, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0213.
Testo completoAbstract (sommario):
Over the past thirty years, price relativities and technological development have motivated an increase in the area of land allocated to cropping, as opposed to pasture production, throughout the central wheat belt of Western Australia. Nevertheless, reducing the proportion of pasture in these rotations has challenged the future productivity of farming systems in this area. First, the frequent application of selective herbicides for weed control in extended cropping rotations has promoted the development of herbicide resistance in a number of major agricultural weeds. Second, the primary use of annual plants has promoted the development of soil salinisation by allowing a significant proportion of rainfall to recharge saline water tables. The inclusion of perennial pasture phases between extended periods of cropping may mitigate or delay these constraints to production through (a) allowing the use of costeffective forms of non-selective weed control, and (b) through creating a buffer of dry soil that absorbs leakage occurring beneath subsequent crops. This study consequently explores the value of including perennial pasture phases in dryland agricultural systems in the eastern-central wheat belt of Western Australia, accounting for benefits related to herbicide resistance and water table management. A novel computational algorithm for the solution of multiple-phase optimal control problems is developed and used to conduct a conceptual analysis of the value of lucerne (Medicago sativa L.) pasture for managing annual ryegrass (Lolium rigidum Gaudin), the primary weed in wheat belt cropping systems. The competitiveness and fecundity of annual ryegrass provide strong economic incentives to maintain a low weed population, irrespective of herbicide-resistance status. Consequently, the ineffectiveness of selective herbicides primarily reduces the profitability of cropping by motivating the adoption of more costly non-selective forms of weed control. The inclusion of lucerne in land-use rotations is only optimal in the presence of severe herbicide resistance given (a) the low efficiency of alternative weed-management practices available during the pasture phase, relative to selective-herbicide application; (b) the significant cost of establishing this perennial pasture; and (c) the high relative profitability of cereal production in the absence of resistance. The value of lucerne, relative to annual pastures, for weed management is explored in greater detail through the use of compressed annealing to optimise a sophisticated simulation model. The profitability of candidate rotations is also manipulated to account for the long-term production losses accruing to the recharge of saline groundwaters that occurs beneath them. Sequences incorporating lucerne are only more profitable than those that include annual pasture at the standard set of parameter values if (a) annual ryegrass is resistant to all selective herbicides, (b) the water table is so shallow (approximately less than 3.5 m deep) that frequent rotation with perennials is required to avert soil salinisation, or (c) sheep production is highly profitable. The value of perennial pasture is sufficient under these circumstances to overcome its high establishment cost. Consistent with intuition, these benefits are reinforced by lower discount rates and higher rates of leakage occurring beneath annual-based systems. Formulation of an effective communication strategy to report these results to producers is justified given the complexity involved in determining the true magnitude of these intertemporal benefits through alternative means, such as field trials.
4
Christodoulou, Nicholas. "Learning to develop participative processes to improve farming systems in the Balonne Shire, Queensland". Thesis, View thesis View thesis, 2000. http://handle.uws.edu.au:8081/1959.7/302.
Testo completoAbstract (sommario):
This thesis develops two related themes.The first is that participatory approaches to agricultural research and extension can provide a sound process for all stakeholders to learn how to develop more sustainable agriculture. The second is that appropriate levels of participation can be used to link knowledge from three important sources: local knowledge, scientific knowledge and experiential knowledge.The thesis develops these two related themes by examining the inconsistencies between esposed theories of participatory approaches (i.e.intended behaviour) and theories in action (i.e. what is actually practised).The study was based upon the work of a major research, development and extension (R, D and E)project known as the Western Farming Systems Project (WSFP),which was concerned with the development of sustainable rotations and cropping practices in south western Queensland and north western N.S.W. between 1994-1999. The study was conducted in the Balonne Shire, centred on the town of St. George, Queensland, Australia.
5
Potter, Mark. "Biochemical studies of tissue glucosinolates for improvement of canola (Brassica napus) as a disease break within the southern Australian cereal rotation /". Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09php8678.pdf.
Testo completoAbstract (sommario):
Thesis (Ph.D) -- University of Adelaide, Depts. of Plant Science and Crop Protection, 1998.Thesis (Ph.D.)--University of Adelaide, Depts. of Plant Science and Crop Protection, 1999? Bibliographical references: leaves 112-125.
6
Wildy, Daniel Thomas. "Growing mallee eucalypts as short-rotation tree crops in the semi-arid wheatbelt of Western Australia". University of Western Australia. School of Plant Biology, 2004. http://theses.library.uwa.edu.au/adt-WU2004.0031.
Testo completoAbstract (sommario):
[Truncated abstract] Insufficient water use by annual crop and pasture species leading to costly rises in saline watertables has prompted research into potentially profitable deep-rooted perennial species in the Western Australian wheatbelt. Native mallee eucalypts are currently being developed as a short-rotation coppice crop for production of leaf oils, activated carbon and bio-electricity for low rainfall areas (300—450 mm) too dry for many of the traditional timber and forage species. The research in this study was aimed at developing a knowledge base necessary to grow and manage coppiced mallee eucalypts for both high productivity and salinity control. This firstly necessitated identification of suitable species, climatic and site requirements favourable to rapid growth, and understanding of factors likely to affect yield of the desirable leaf oil constituent, 1,8-cineole. This was undertaken using nine mallee taxa at twelve sites with two harvest regimes. E. kochii subsp. plenissima emerged as showing promise in the central and northern wheatbelt, particularly at a deep acid sand site (Gn 2.61; Northcote, 1979), so further studies focussed on physiology of its resprouting, water use and water-use efficiency at a similar site near Kalannie. Young E. kochii trees were well equipped with large numbers of meristematic foci and adequate root starch reserves to endure repeated shoot removal. The cutting season and interval between cuts were then demonstrated to have a strong influence on productivity, since first-year coppice growth was slow and root systems appeared to cease in secondary growth during the first 1.5—2.5 years after cutting. After decapitation, trees altered their physiology to promote rapid replacement of shoots. Compared to uncut trees, leaves of coppices were formed with a low carbon content per unit area, and showed high stomatal conductance accompanied by high leaf photosynthetic rates. Whole-plant water use efficiency of coppiced trees was unusually high due to their fast relative growth rates associated with preferential investments of photosynthates into regenerating canopies rather than roots. Despite relatively small leaf areas on coppice shoots over the two years following decapitation, high leaf transpiration rates resulted in coppices using water at rates far in excess of that falling as rain on the tree belt area. Water budgets showed that 20 % of the study paddock would have been needed as 0—2 year coppices in 5 m wide twin-row belts in order to maintain hydrological balance over the study period. Maximum water use occurred where uncut trees were accessing a fresh perched aquifer, but where this was not present water budgets still showed transpiration of uncut trees occurring at rates equivalent to 3—4 times rainfall incident on the tree belt canopy. In this scenario, only 10 % of the paddock surface would have been required under 5 m wide tree belts to restore hydrological balance, but competition losses in adjacent pasture would have been greater
7
Adcock, Damien Paul. "Soil water and nitrogen dynamics of farming systems on the upper Eyre Peninsula, South Australia". 2005. http://hdl.handle.net/2440/37810.
Testo completoAbstract (sommario):
In the semi - arid Mediterranean - type environments of southern Australia, soil and water resources largely determine crop productivity and ultimately the sustainability of farming systems within the region. The development of sustainable farming systems is a constantly evolving process, of which cropping sequences ( rotations ) are an essential component. This thesis focused on two important soil resources, soil water and nitrogen, and studied the effects of different crop sequences on the dynamic of these resources within current farming systems practiced on the upper Eyre Peninsula of South Australia. The hypothesis tested was that : continuous cropping may alter N dynamics but will not necessarily alter water use efficiency in semi - arid Mediterranean - type environments. Continuous cropping altered N - dynamics ; increases in inorganic N were dependent on the inclusion of a legume in the cropping sequence. Associated with the increase in inorganic N supply was a decrease in WUE by the subsequent wheat crop. Overall, estimates of water use efficiency, a common index of the sustainability of farming systems, in this study concur with reported values for the semi - arid Murray - Mallee region of southern Australia and other semi - arid environments worldwide. Soil water balance and determination of WUE for a series of crop sequences in this thesis suggests that the adoption of continuous cropping may increase WUE and confer a yield benefit compared to crop sequences including a legume component in this environment. No differences in total water use ( ET ) at anthesis or maturity were measured for wheat regardless of the previous crop. Soil evaporation ( E [subscript s] ) was significantly affected by crop canopy development, measured as LAI from tillering until anthesis in 2002, however total seasonal E [subscript s] did not differ between crop sequences. Indeed in environments with infrequent rainfall, such as the upper Eyre Peninsula, soil evaporation may be water - limited rather than energy limited and the potential benefits from greater LAI and reduced E [subscript s] are less. Greater shoot dry matter production and LAI due to an enhanced inorganic N supply for wheat after legumes, and to a lesser degree wheat after canola, relative to continuous cereal crop sequences resulted in increases in WUE calculated at anthesis, as reported by others. Nonetheless the increase in WUE was not sustained due to limitations on available soil water capacity caused by soil physical and chemical constraints. Access to more soil water at depth ( > 0.8m ) through additional root growth was unavailable due to soil chemical limitations. More importantly, the amount of plant available water within the ' effective rooting depth ' ( 0 - 0.8m ) was significantly reduced when soil physical factors were accounted for using the integral water capacity ( IWC ) concept. The difference between the magnitude of the plant available water capacity and the integral water capacity was approximately 90mm within the ' effective rooting depth ' when measured at field capacity, suggesting that the ability of the soil to store water and buffer against periodic water deficit was severely limited. The IWC concept offers a method of evaluating the physical quality of soils and the limitations that these physical properties, viz. aeration, soil strength and hydraulic conductivity, impose on the water supply capacity of the soil. The inability of the soil to maintain a constant supply of water to satisfy maximal transpiration efficiency combined with large amounts of N resulted in ' haying off ', and reduced grain yields. A strong negative linear relationship was established between WUE of grain production by wheat and increasing soil NO [subscript 3] - N at sowing in 2000 and 2002, which conflicts with results from experiments in semi - arid Mediterranean climates in other regions of the world where applications of N increased water use efficiency of grain. Estimates of proportional dependence on N [subscript 2] fixation ( % N [subscript dfa] ) for annual medics and vetch from this study ( 43 - 80 % ) are comparable to others for environments in southern Australia ( < 450mm average annual rainfall ). Such estimates of fixation are considered low ( < 65 % ) to adequate ( 65 - 80 % ). Nevertheless, the amount of plant available N present at sowing for subsequent wheat crops, and the occurrence of ' haying off ', suggests that WUE is not N - limited per se, as implied by some reports, but constrained by the capacity of a soil to balance the co - limiting factors of water and nitrogen.Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2005.
8
Omokanye, Akim Tunde. "Biological and economic evaluation of maize-based cropping systems for Nigerian smallholders". Thesis, 2004. http://handle.uws.edu.au:8081/1959.7/797.
Testo completoAbstract (sommario):
Indigenous African shifting cultivation production systems, that were developed over many generations and took into account production potential as well as the constraints imposed by natural resources, are no longer practicable for Nigerian smallholder farmers. These systems relied on long fallow for fertility restoration after a period of cropping. Overpopulation has resulted in lower per capita land availability, necessitating a shift to sedentary cultivation systems. In such systems, fallow is short term (months) compared to shifting systems, where it lasted several years. This shift has resulted in overexploitation of land resources and despite intensification of agricultural production methods, non-sustainable demand on the natural resource base has increased and crop and animal production has declined. This study examined the performance of five maize-based cropping systems consisting of cereal-legume, cereal-cereal and cereal bare fallow rotations, to identify systems that have potential for increased agricultural production in the subhumid and mid-altitude zones of Nigeria. The study was conducted at Richmond, near Sydney, in NSW, Australia from 2000 to 2003. The trial investigated the effects of the combined use of legumes and N fertilizer in CSs to maintain or improve soil fertility, maize crop and maize storage silage production and yield and quality of all crop residues. This study showed that inclusion of a legume in the rotation is an important production and income generating strategy. Owing to their potential for increased maize productivity, to build up N-rich systems and to improve small holder levels of farm income, cropping systems with legumes should therefore be given more research attention in Nigeria
9
Adcock, Damien Paul. "Soil water and nitrogen dynamics of farming systems on the upper Eyre Peninsula, South Australia". Thesis, 2005. http://hdl.handle.net/2440/37810.
Testo completoAbstract (sommario):
In the semi - arid Mediterranean - type environments of southern Australia, soil
and water resources largely determine crop productivity and ultimately the sustainability of farming systems within the region. The development of sustainable farming systems is a constantly evolving process, of which cropping
sequences ( rotations ) are an essential component. This thesis focused on two important soil resources, soil water and nitrogen, and studied the effects of different crop sequences on the dynamic of these resources within current farming systems practiced on the upper Eyre Peninsula of South Australia.
The hypothesis tested was that : continuous cropping may alter N dynamics but will not necessarily alter water use efficiency in semi - arid Mediterranean - type environments. Continuous cropping altered N - dynamics ; increases in inorganic N were dependent on the inclusion of a legume in the cropping sequence.
Associated with the increase in inorganic N supply was a decrease in WUE by the subsequent wheat crop. Overall, estimates of water use efficiency, a common index of the sustainability of farming systems, in this study concur with reported values for the semi - arid Murray - Mallee region of southern Australia and other
semi - arid environments worldwide.
Soil water balance and determination of WUE for a series of crop sequences in this thesis suggests that the adoption of continuous cropping may increase WUE and confer a yield benefit compared to crop sequences including a legume component in this environment. No differences in total water use ( ET ) at anthesis or maturity were measured for wheat regardless of the previous crop. Soil evaporation ( E [subscript s] ) was significantly affected by crop canopy development, measured as LAI from tillering until anthesis in 2002, however total seasonal E [subscript s] did not differ between crop sequences. Indeed in environments with infrequent
rainfall, such as the upper Eyre Peninsula, soil evaporation may be water - limited rather than energy limited and the potential benefits from greater LAI and reduced E [subscript s] are less.
Greater shoot dry matter production and LAI due to an enhanced inorganic N supply for wheat after legumes, and to a lesser degree wheat after canola, relative to continuous cereal crop sequences resulted in increases in WUE calculated at anthesis, as reported by others. Nonetheless the increase in WUE was not sustained due to limitations on available soil water capacity caused by soil physical and chemical constraints. Access to more soil water at depth ( > 0.8m ) through additional root growth was unavailable due to soil chemical limitations. More importantly, the amount of plant available water within the ' effective rooting depth ' ( 0 - 0.8m ) was significantly reduced when soil physical factors were accounted for using the integral water capacity ( IWC ) concept. The difference between the magnitude of the plant available water capacity and the integral water capacity was approximately 90mm within the ' effective rooting depth ' when measured at field capacity, suggesting that the ability of the soil to store water and buffer against periodic water deficit was severely limited. The IWC concept offers a method of evaluating the physical quality of soils and the limitations that these physical properties, viz. aeration, soil strength and hydraulic conductivity, impose on the water supply capacity of the soil.
The inability of the soil to maintain a constant supply of water to satisfy maximal transpiration efficiency combined with large amounts of N resulted in ' haying off ', and reduced grain yields. A strong negative linear relationship was established between WUE of grain production by wheat and increasing soil NO₃ - N at sowing in 2000 and 2002, which conflicts with results from experiments in
semi - arid Mediterranean climates in other regions of the world where applications of N increased water use efficiency of grain.
Estimates of proportional dependence on N₂ fixation ( % N [subscript dfa] ) for annual medics and vetch from this study ( 43 - 80 % ) are comparable to others for environments in southern Australia ( < 450mm average annual rainfall ). Such
estimates of fixation are considered low ( < 65 % ) to adequate ( 65 - 80 % ). Nevertheless, the amount of plant available N present at sowing for subsequent
wheat crops, and the occurrence of ' haying off ', suggests that WUE is not N - limited
per se, as implied by some reports, but constrained by the capacity of a soil to balance the co - limiting factors of water and nitrogen.Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2005.
Libri sul tema "Crop rotation (Australia)"
1
Walton, G. H. Evaluation of pulses and other seed legumes for crop rotations in Western australia. Perth: Department of Agriculture, 1988.
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2
Short-rotation crops for bioenergy: Proceedings of the fourth meeting of IEA, Bioenergy, Task 17, held at Albany, Western Australia 7-9 March, 2000. Bentley Delivery Centre, Western Australia: Dept. of Conservation and Land Management, 2000.
Cerca il testo completoCapitoli di libri sul tema "Crop rotation (Australia)"
1
Rochecouste, Jean-Francois, John Baker e Bill Crabtree. "Conservation Agriculture in Australian dryland cropping and in New Zealand: the lessons of 70 years". In Burleigh Dodds Series in Agricultural Science, 599–624. Burleigh Dodds Science Publishing, 2022. http://dx.doi.org/10.19103/as.2021.0088.15.
Testo completoAbstract (sommario):
Australia and New Zealand have seen a rapid adoption rate in Conservation Agriculture in the areas of no-till and stubble retention. The two countries have different stories, and this will be highlighted in this chapter. For Australia crop diversification has not changed substantially, and the balance required between diversification and the variable return of different crops is still a major challenge for farmers, with wheat remaining over half of the national crop. The main changes in tillage practices involved the adoption of narrow tine and disc planters to minimise soil disturbance along with stubble retention, crop rotation and controlled traffic farming have followed suit. Current trends involve an increasing use of GPS technology combined with remote and proximal sensors to more efficiently deliver resources such as fertiliser and chemicals. Precision technology is also being used to reposition the planting row to the inter-row between the standing stubble. Herbicide resistance is becoming an increasing problem. Emerging issues include nutrient stratification, sub-surface acidification and an increase in diseases from stubble retention.
2
Coventry, David, Alireza Farhoodi e Ren-kou Xu. "Managing Soil Acidification Through Crop Rotations in Southern Australia". In Handbook of Soil Acidity. CRC Press, 2003. http://dx.doi.org/10.1201/9780203912317.ch15.
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