The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Ann Mcneill - One of the best experts on this subject based on the ideXlab platform.
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Phosphorus uptake benefit for wheat following legume Break Crops in semi-arid Australian farming systems
Nutrient Cycling in Agroecosystems, 2019Co-Authors: Ashlea L Doolette, Roger Armstrong, Caixian Tang, Christopher N Guppy, Sean Mason, Ann McneillAbstract:This field study assessed phosphorus dynamics (crop-P uptake, resin-extractable P in the root-zone, P mobilisation and microbial-P) in Break crop-cereal rotation sequences at four Australian semi-arid field sites differing in soil P fertility. Phosphorus mobilisation (9–30 kg P ha^−1) was apparent under Break Crops, consistently under canola and peas at three sites with low soil P fertility (i.e. pre-sowing soil resin-extractable P
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phosphorus uptake benefit for wheat following legume Break Crops in semi arid australian farming systems
Nutrient Cycling in Agroecosystems, 2019Co-Authors: Ashlea L Doolette, Roger Armstrong, Caixian Tang, Christopher N Guppy, Sean Mason, Ann McneillAbstract:This field study assessed phosphorus dynamics (crop-P uptake, resin-extractable P in the root-zone, P mobilisation and microbial-P) in Break crop-cereal rotation sequences at four Australian semi-arid field sites differing in soil P fertility. Phosphorus mobilisation (9–30 kg P ha−1) was apparent under Break Crops, consistently under canola and peas at three sites with low soil P fertility (i.e. pre-sowing soil resin-extractable P < 20 mg P kg−1). Enhanced biological cycling of P (i.e. increased microbial-P) was limited to a low P site in the Break crop phase. Phosphorus content of Break crop aboveground residues following grain removal was 1–7 kg P ha−1; P input was greater (12–18 kg P ha−1) where legumes were green/brown manured. Varied residue P input did not result in differences in resin-extractable or microbial-P in soil prior to sowing wheat. Phosphorus uptake was greater for wheat after legume Break Crops compared to continuous wheat (2.0–4.7 kg P ha−1) at all sites, especially where Crops were green/brown-manured (3.9–5.9 kg P ha−1). Greater P uptake by wheat was associated with increased grain yield at three sites but was not significantly correlated with the quantity of P input from Break crop residues at all four sites or with soil mineral nitrogen pre-sowing of wheat at three sites. Break Crops can directly contribute to P resource-use efficiency by mobilising residual P from soil but the agronomic significance of P supply from Break crop residues to a P uptake benefit for following wheat remains to be elucidated.
A M Litterick - One of the best experts on this subject based on the ideXlab platform.
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The Agronomic and Economic Potential of Break Crops for Ley/Arable Rotations in Temperate Organic Agriculture
Advances in Agronomy, 2020Co-Authors: M C Robson, S M Fowler, Nic Lampkin, Carlo Leifert, Malcolm H Leitch, David Robinson, C A Watson, A M LitterickAbstract:Organic farming principles dictate that cereals cannot be grown continuously, and in practice they are rarely grown for more than 50% of the rotation. Choice of Break Crops to grow in addition to cereals and the fertility building phase are crucial to both the agronomic and economic success of the rotation on organic arable farms. There are four specific functions that a Break crop may perform, namely, addition, conservation, and cycling of nutrients; pest and/or disease control; weed control and improvement in soil physical characteristics. Individual Break Crops may perform one or several of these functions. A good Break crop must also produce satisfactory yields, be of marketable quality, and produce an economic return for the farmer. This review assesses the potential of 10 Break Crops (bean, lupin, soybean, hemp, oilseed rape, potato, carrot, swede, sugar beet, linola) in terms of their Break function, their impact on the subsequent crop in temperate organic agricultural systems, and their economic value in UK agriculture. All species assessed had valuable Break crop characteristics. Hemp, lupin, and faba bean had the greatest economic potential, but hemp and lupin currently generate poor economic returns. Linola and soybean are useful Break Crops, although soybean may have allelopathic effects on subsequent wheat seedlings. Swede, potato, and carrot are the most profitable Crops, but are less valuable in the rotation in terms of soil fertility than hemp, bean, or lupin. Sugar beet and oilseed rape are difficult to grow organically and at present have limited organic markets.
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An investigation into the relationship between preceding Break Crops and weed populations in barley Crops in organic ley/arable rotations
2020Co-Authors: A M Litterick, C A Watson, M C RobsonAbstract:This report was presented at the UK Organic Research 2002 Conference. The relationship between weed populations and cereal Crops following nine organic Break Crops was investigated in field trials in Warwickshire, Aberdeenshire and Ceredigion in 2001. Weed biodiversity was high on all sites and varied between sites in terms of species present. Severity of weed infestation differed significantly between sites and between cereals following different Break Crops. The impact of Break crop species on the incidence and severity of the weed burden in the following cereal is discussed in relation to the field trials at the three sites.
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the agronomic and economic potential of Break Crops for ley arable rotations in temperate organic agriculture
Advances in Agronomy, 2002Co-Authors: M C Robson, S M Fowler, Nic Lampkin, Carlo Leifert, Malcolm H Leitch, David Robinson, C A Watson, A M LitterickAbstract:Organic farming principles dictate that cereals cannot be grown continuously, and in practice they are rarely grown for more than 50% of the rotation. Choice of Break Crops to grow in addition to cereals and the fertility building phase are crucial to both the agronomic and economic success of the rotation on organic arable farms. There are four specific functions that a Break crop may perform, namely, addition, conservation, and cycling of nutrients; pest and/or disease control; weed control and improvement in soil physical characteristics. Individual Break Crops may perform one or several of these functions. A good Break crop must also produce satisfactory yields, be of marketable quality, and produce an economic return for the farmer. This review assesses the potential of 10 Break Crops (bean, lupin, soybean, hemp, oilseed rape, potato, carrot, swede, sugar beet, linola) in terms of their Break function, their impact on the subsequent crop in temperate organic agricultural systems, and their economic value in UK agriculture. All species assessed had valuable Break crop characteristics. Hemp, lupin, and faba bean had the greatest economic potential, but hemp and lupin currently generate poor economic returns. Linola and soybean are useful Break Crops, although soybean may have allelopathic effects on subsequent wheat seedlings. Swede, potato, and carrot are the most profitable Crops, but are less valuable in the rotation in terms of soil fertility than hemp, bean, or lupin. Sugar beet and oilseed rape are difficult to grow organically and at present have limited organic markets.
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an investigation into the relationship between preceding Break Crops and weed populations in barley Crops in organic ley arable rotations
2002Co-Authors: A M Litterick, C A Watson, M C RobsonAbstract:This report was presented at the UK Organic Research 2002 Conference. The relationship between weed populations and cereal Crops following nine organic Break Crops was investigated in field trials in Warwickshire, Aberdeenshire and Ceredigion in 2001. Weed biodiversity was high on all sites and varied between sites in terms of species present. Severity of weed infestation differed significantly between sites and between cereals following different Break Crops. The impact of Break crop species on the incidence and severity of the weed burden in the following cereal is discussed in relation to the field trials at the three sites.
M C Robson - One of the best experts on this subject based on the ideXlab platform.
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The Agronomic and Economic Potential of Break Crops for Ley/Arable Rotations in Temperate Organic Agriculture
Advances in Agronomy, 2020Co-Authors: M C Robson, S M Fowler, Nic Lampkin, Carlo Leifert, Malcolm H Leitch, David Robinson, C A Watson, A M LitterickAbstract:Organic farming principles dictate that cereals cannot be grown continuously, and in practice they are rarely grown for more than 50% of the rotation. Choice of Break Crops to grow in addition to cereals and the fertility building phase are crucial to both the agronomic and economic success of the rotation on organic arable farms. There are four specific functions that a Break crop may perform, namely, addition, conservation, and cycling of nutrients; pest and/or disease control; weed control and improvement in soil physical characteristics. Individual Break Crops may perform one or several of these functions. A good Break crop must also produce satisfactory yields, be of marketable quality, and produce an economic return for the farmer. This review assesses the potential of 10 Break Crops (bean, lupin, soybean, hemp, oilseed rape, potato, carrot, swede, sugar beet, linola) in terms of their Break function, their impact on the subsequent crop in temperate organic agricultural systems, and their economic value in UK agriculture. All species assessed had valuable Break crop characteristics. Hemp, lupin, and faba bean had the greatest economic potential, but hemp and lupin currently generate poor economic returns. Linola and soybean are useful Break Crops, although soybean may have allelopathic effects on subsequent wheat seedlings. Swede, potato, and carrot are the most profitable Crops, but are less valuable in the rotation in terms of soil fertility than hemp, bean, or lupin. Sugar beet and oilseed rape are difficult to grow organically and at present have limited organic markets.
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An investigation into the relationship between preceding Break Crops and weed populations in barley Crops in organic ley/arable rotations
2020Co-Authors: A M Litterick, C A Watson, M C RobsonAbstract:This report was presented at the UK Organic Research 2002 Conference. The relationship between weed populations and cereal Crops following nine organic Break Crops was investigated in field trials in Warwickshire, Aberdeenshire and Ceredigion in 2001. Weed biodiversity was high on all sites and varied between sites in terms of species present. Severity of weed infestation differed significantly between sites and between cereals following different Break Crops. The impact of Break crop species on the incidence and severity of the weed burden in the following cereal is discussed in relation to the field trials at the three sites.
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the agronomic and economic potential of Break Crops for ley arable rotations in temperate organic agriculture
Advances in Agronomy, 2002Co-Authors: M C Robson, S M Fowler, Nic Lampkin, Carlo Leifert, Malcolm H Leitch, David Robinson, C A Watson, A M LitterickAbstract:Organic farming principles dictate that cereals cannot be grown continuously, and in practice they are rarely grown for more than 50% of the rotation. Choice of Break Crops to grow in addition to cereals and the fertility building phase are crucial to both the agronomic and economic success of the rotation on organic arable farms. There are four specific functions that a Break crop may perform, namely, addition, conservation, and cycling of nutrients; pest and/or disease control; weed control and improvement in soil physical characteristics. Individual Break Crops may perform one or several of these functions. A good Break crop must also produce satisfactory yields, be of marketable quality, and produce an economic return for the farmer. This review assesses the potential of 10 Break Crops (bean, lupin, soybean, hemp, oilseed rape, potato, carrot, swede, sugar beet, linola) in terms of their Break function, their impact on the subsequent crop in temperate organic agricultural systems, and their economic value in UK agriculture. All species assessed had valuable Break crop characteristics. Hemp, lupin, and faba bean had the greatest economic potential, but hemp and lupin currently generate poor economic returns. Linola and soybean are useful Break Crops, although soybean may have allelopathic effects on subsequent wheat seedlings. Swede, potato, and carrot are the most profitable Crops, but are less valuable in the rotation in terms of soil fertility than hemp, bean, or lupin. Sugar beet and oilseed rape are difficult to grow organically and at present have limited organic markets.
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an investigation into the relationship between preceding Break Crops and weed populations in barley Crops in organic ley arable rotations
2002Co-Authors: A M Litterick, C A Watson, M C RobsonAbstract:This report was presented at the UK Organic Research 2002 Conference. The relationship between weed populations and cereal Crops following nine organic Break Crops was investigated in field trials in Warwickshire, Aberdeenshire and Ceredigion in 2001. Weed biodiversity was high on all sites and varied between sites in terms of species present. Severity of weed infestation differed significantly between sites and between cereals following different Break Crops. The impact of Break crop species on the incidence and severity of the weed burden in the following cereal is discussed in relation to the field trials at the three sites.
Ashlea L Doolette - One of the best experts on this subject based on the ideXlab platform.
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Phosphorus uptake benefit for wheat following legume Break Crops in semi-arid Australian farming systems
Nutrient Cycling in Agroecosystems, 2019Co-Authors: Ashlea L Doolette, Roger Armstrong, Caixian Tang, Christopher N Guppy, Sean Mason, Ann McneillAbstract:This field study assessed phosphorus dynamics (crop-P uptake, resin-extractable P in the root-zone, P mobilisation and microbial-P) in Break crop-cereal rotation sequences at four Australian semi-arid field sites differing in soil P fertility. Phosphorus mobilisation (9–30 kg P ha^−1) was apparent under Break Crops, consistently under canola and peas at three sites with low soil P fertility (i.e. pre-sowing soil resin-extractable P
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phosphorus uptake benefit for wheat following legume Break Crops in semi arid australian farming systems
Nutrient Cycling in Agroecosystems, 2019Co-Authors: Ashlea L Doolette, Roger Armstrong, Caixian Tang, Christopher N Guppy, Sean Mason, Ann McneillAbstract:This field study assessed phosphorus dynamics (crop-P uptake, resin-extractable P in the root-zone, P mobilisation and microbial-P) in Break crop-cereal rotation sequences at four Australian semi-arid field sites differing in soil P fertility. Phosphorus mobilisation (9–30 kg P ha−1) was apparent under Break Crops, consistently under canola and peas at three sites with low soil P fertility (i.e. pre-sowing soil resin-extractable P < 20 mg P kg−1). Enhanced biological cycling of P (i.e. increased microbial-P) was limited to a low P site in the Break crop phase. Phosphorus content of Break crop aboveground residues following grain removal was 1–7 kg P ha−1; P input was greater (12–18 kg P ha−1) where legumes were green/brown manured. Varied residue P input did not result in differences in resin-extractable or microbial-P in soil prior to sowing wheat. Phosphorus uptake was greater for wheat after legume Break Crops compared to continuous wheat (2.0–4.7 kg P ha−1) at all sites, especially where Crops were green/brown-manured (3.9–5.9 kg P ha−1). Greater P uptake by wheat was associated with increased grain yield at three sites but was not significantly correlated with the quantity of P input from Break crop residues at all four sites or with soil mineral nitrogen pre-sowing of wheat at three sites. Break Crops can directly contribute to P resource-use efficiency by mobilising residual P from soil but the agronomic significance of P supply from Break crop residues to a P uptake benefit for following wheat remains to be elucidated.
J A Kirkegaard - One of the best experts on this subject based on the ideXlab platform.
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Break Crops and rotations for wheat
Crop & Pasture Science, 2015Co-Authors: J F Angus, J A Kirkegaard, James R Hunt, Megan H Ryan, L Ohlander, M B PeoplesAbstract:Wheat Crops usually yield more when grown after another species than when grown after wheat. Quantifying the yield increase and explaining the factors that affect the increase will assist farmers to decide on crop sequences. This review quantifies the yield increase, based on >900 comparisons of wheat growing after a Break crop with wheat after wheat. The mean increase in wheat yield varied with species of Break crop, ranging from 0.5 t ha–1 after oats to 1.2 t ha–1 after grain legumes. Based on overlapping experiments, the observed ranking of Break-crop species in terms of mean yield response of the following wheat crop was: oats < canola ≈ mustard ≈ flax < field peas ≈ faba beans ≈ chickpeas ≈ lentils ≈ lupins. The mean additional wheat yield after oats or oilseed Break Crops was independent of the yield level of the following wheat crop. The wheat yield response to legume Break Crops was not clearly independent of yield level and was relatively greater at high yields. The yield of wheat after two successive Break Crops was 0.1–0.3 t ha–1 greater than after a single Break crop. The additional yield of a second wheat crop after a single Break crop ranged from 20% of the effect on a first wheat crop after canola, to 60% after legumes. The mean yield effect on a third wheat crop was negligible, except in persistently dry conditions. The variability of the Break-crop effect on the yield of a second wheat crop was larger than of a first wheat crop, particularly following canola. We discuss the responses in relation to mechanisms by which Break Crops affect soil and following Crops. By quantifying the magnitude and persistence of Break-crop effects, we aim to provide a basis for the decision to grow continuous cereal Crops, strategic rotations or tactically selected Break Crops. In many wheat-growing areas, the large potential yield increases due to Break Crops are not fully exploited. Research into quantifying the net benefits of Break Crops, determining the situations where the benefits are greatest, and improving the benefits of Break Crops promises to improve the efficiency of wheat-based cropping systems.
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Break Crops and rotations for wheat
Crop & Pasture Science, 2015Co-Authors: John Angus, J A Kirkegaard, James R Hunt, Megan H Ryan, L Ohlander, M B PeoplesAbstract:Wheat Crops usually yield more when grown after another species than when grown after wheat. Quantifying the yield increase and explaining the factors that affect the increase will assist farmers to decide on crop sequences. This review quantifies the yield increase, based on >900 comparisons of wheat growing after a Break crop with wheat after wheat. The mean increase in wheat yield varied with species of Break crop, ranging from 0.5 t ha–1 after oats to 1.2 t ha–1 after grain legumes. Based on overlapping experiments, the observed ranking of Break-crop species in terms of mean yield response of the following wheat crop was: oats
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Dynamic crop sequencing in Western Australian cropping systems
Crop & Pasture Science, 2015Co-Authors: R. S. Malik, J A Kirkegaard, Roger Lawes, Mark Seymour, Robert J. French, Mark A. LiebigAbstract:During the last two decades in Western Australia, the traditional mixed farming system has been increasingly displaced by intensive crop sequences dominated by wheat. Intensive wheat sequences are usually maintained by using suitable Breaks, including pasture, fallow, or alternative cereal, oilseed and legume Crops, to control weeds and disease, or maintain the supply of nitrogen to Crops. New cereal fungicide options may also assist to maintain intensive cereal systems by suppressing soilborne cereal diseases. To guide the successful diversification of intensive cereal systems, we evaluated the effect of a 2-year experimental matrix of 10 different sequence options. Wheat in the sequence was treated with the fluquinconazole fungicide Jockey (wheat + J) to control soilborne pathogens, or with the usual seed dressing of flutriafol fungicide (wheat – J), used for control of bunts and smuts only. The sequences were wheat + J, wheat – J, barley, grain oats, oaten hay, canola, lupin, field pea, oat–vetch green manure, bare fallow) in which all treatment combinations were grown in year 2 following the same 10 treatments in year 1. In year 3, wheat + J was grown across the entire area as the test crop. In year 2, grain yields of all Crops were reduced when Crops were grown on their own residues, including wheat (22% reduction), canola (46%), lupin (40%) and field pea (51%). Wheat + J significantly outyielded wheat – J by 300 kg ha–1 in year 1 (14% increase) and 535 kg ha–1 in year 2 (26% increase). Wheat + J was more responsive to Break Crops than wheat – J in both year 1 and year 2. Break Crops sown in year 1, such as canola, fallow, field pea, lupin and oaten hay, continued to have a positive effect on year 3 wheat + J yields. This study has highlighted the importance of Break Crops to following cereal Crops, and provided an example in which a seed-dressing fungicide fluquinconazole in the presence of low levels of disease consistently improved wheat yields.
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Evaluating the contribution of take-all control to the Break-crop effect in wheat
Crop & Pasture Science, 2013Co-Authors: Roger Lawes, J A Kirkegaard, Vadakattu V. S. R. Gupta, D. RogetAbstract:Break-Crops such as legumes and oilseeds increase the yield of subsequent cereal Crops by reducing the level of diseases and weeds that build in continuous cereal Crops, and can also improve water and nitrogen supply. Although the term ‘Break-crop’ originates from their role in Breaking disease cycles of soil-borne diseases such as take-all (caused by Gaeumannomyces graminis var. tritici), the contribution of take-all control to the overall Break-crop effect has not been separated in most studies. We re-analysed a range of medium- and short-term crop-sequencing experiments comprising 18 year × site combinations in diverse environments in southern Australia. An analysis using linear mixed effects models was conducted to: (i) define the agro-environments that lead to increases in take-all incidence in continuous wheat crop sequences, (ii) quantify the effect of take-all on wheat yield, and (iii) ascertain the contribution of the reduction in take-all following Break-Crops to the size of the total Break-crop effect on wheat crop yield. Break-crop effects on wheat yield averaged 0.7 t/ha and ranged from 0 to 2.1 t/ha. On 14 of 18 occasions, take-all contributed to reduced wheat yield in continuous wheat rotations, although the estimated effect exceeded 0.1 t/ha on just six of those occasions. As a result, reduced take-all by Break-Crops contributed to
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The agronomic relevance of arbuscular mycorrhizas in the fertility of Australian extensive cropping systems
Agriculture Ecosystems & Environment, 2012Co-Authors: Megan H Ryan, J A KirkegaardAbstract:Abstract All available data on arbuscular mycorrhizal fungi (AMF) in Australian extensive cropping systems are reviewed in an agronomic framework. In the southern temperate and northern subtropical zones, 80–85% and 60%, respectively, of cropped area is winter cereals. In the south, non-mycorrhizal winter Break Crops are common and Crops are often rotated with low input pastures. In the north, continuous cropping with winter Crops, summer Crops and long (12–18 month) plant-free fallow is common. Only here does reduced colonization by AMF cause intermittent yield reductions, perhaps reflecting low phosphorus (P) soils, high crop growth rates and dry surface soil limiting P availability. Soil temperatures below 10 °C may limit the contribution of AMF to southern Crops. In both zones, wheat yields are generally enhanced following fallows and non-mycorrhizal Break Crops, even under P limitation. AMF are unlikely to aid control of root diseases or dryland salinity adaptation; their role in soil structure and carbon sequestration requires clarification. Organic Crops are highly colonized, but invariably P deficient. Thus, little evidence supports consideration of AMF in farm management and many agronomic practices that underpin sustainable productivity reduce colonization. We hope this paper stimulates dialog between mycorrhizal researchers and agronomists to target high priority research.
