1421. Crop rotation reduces crown rot in wheat.

• Authors:
  • Simpfendorfer, S.
  • Backhouse, D.
  • Moore, K.
  • Verrell, A.
• Source: Update of research in progress at the Tamworth Agricultural Institute 2002
• Year: 2003
• Summary: A replicated, fully phased, field trial was conducted in Tamworth, New South Wales, Australia, to determine the effects of the most common winter and summer break crops on crown rot (caused by Fusarium pseudograminearum) in wheat. The experiment was established in 2000 by sowing F. pseudograminearum-colonized ryegrass seed with wheat cv. Janz into plots. In 2001, rape, chickpea, faba bean, sorghum or wheat cv. Janz were grown under a no-till system. In 2002, wheat cv. Sunstate was planted across the winter break crop plots. All four rotation crops proved effective breaks for crown rot. They encouraged breakdown of the 2000 Janz residue. Stubble ground cover in May 2002 was 15% for sorghum, 28% for faba beans, 30% for rape, and 41% for chickpea compared with 88% for continuous no-till wheat (and 60% long fallow). The rotation crops also reduced survival of the pathogen with recovery of F. pseudograminearum ranging from 7-13% in crowns to 10-15% in stubble following break crops compared with 33% in crowns and 49% in stubble for continuous no-till wheat. These effects carried through to the 2002 wheat crop where infection of Sunstate plants at tillering ranged from 25% for wheat after rape to 39% for continuous wheat.

1422. Effects of eight years of crop rotation and tillage on nitrogen availability and budget of a sandy loam soil.

• Authors:
  • Clayton, G.
  • Soon, Y.
• Source: Canadian Journal of Soil Science
• Volume: 83
• Issue: 5
• Year: 2003
• Summary: The effects of tillage and crop rotations on soil N availability and economy were evaluated over two rotation cycles to address the paucity of such information. From 1993 through 2000, Leith sandy loam soil (Gray Luvisol) of Alberta, Canada was sampled to 120 cm in the autumn from four crop rotations: (i) continuous wheat ( Triticum aestivum); (ii) field pea ( Pisum sativum)-wheat-rape ( Brassica rapa [ B. campestris])-wheat; (iii) red clover ( Trifolium pratense) green manure-wheat-canola-wheat/red clover; (iv) fallow-wheat-rape-wheat, and analysed for KCl-extractable N. The rotations were managed under a conventional tillage (CT) or a no-till (NT) system, and were fertilized based on soil test results. A N budget was constructed for each cropping system comprising N added in seed and fertilizers, and by symbiotic fixation and N exported in the grain. More nitrate accumulated under CT than NT, resulting in lower N fertilizer application rates for CT plots. Soil mineralizable N was higher under NT than CT, and was not influenced by crop rotations. The trend for residual soil nitrate among crop rotations was: fallow rotation > green manure rotation > continuous wheat > field pea rotation, due mostly to residual nitrate following the first phase of the rotations. There was no interaction of tillage with rotation. The continuous wheat and field pea rotation maintained a balanced N budget. The red clover rotation resulted in net N import in each rotation cycle of approximately 25 kg ha -1 under CT and 37 kg ha -1 under NT; net N export from the fallow rotation was 30 kg ha -1 under NT and 46 kg ha -1 under CT.

1423. Site-specific management zones based on soil electrical conductivity in a semiarid cropping system.

• Authors:
  • Shanahan, J. F.
  • Wienhold, B. J.
  • Mortensen, D. A.
  • Johnson, C. K.
  • Doran, J. W.
• Source: Agronomy Journal
• Volume: 95
• Issue: 2
• Year: 2003
• Summary: Site-specific management (SSM) can potentially improve both economic and ecological outcomes in agriculture. Effective SSM requires strong and temporally consistent relationships among identified management zones; underlying soil physical, chemical, and biological parameters; and crop yields. In the central Great Plains, a 250-ha dryland experiment was mapped for apparent electrical conductivity (EC a). Eight fields were individually partitioned into four management zones based on equal ranges of deep (EC DP) and shallow (EC SH) EC a (approximately 0-30 and 0-90 cm depths, respectively). Previous experiments documented negative correlations between ECSH and soil properties indicative of productivity. The objectives of this study were to examine EC SH and EC DP relationships with 2 yr of winter wheat ( Triticum aestivum L.) and corn ( Zea mays L.) yields and to consider the potential applications of EC a-based management zones for SSM in a semiarid cropping system. Within-zone wheat yield means were negatively correlated with EC SH ( r=-0.97 to -0.99) and positively correlated with EC DP ( r=0.79-0.97). Within-zone corn yield means showed no consistent relationship with EC SH but positive correlation with EC DP ( r=0.81-0.97). Equal-range and unsupervised classification methods were compared for EC SH; within-zone yield variances declined slightly (0-5%) with the unsupervised approach. Yield response curves relating maximum wheat yields and EC SH revealed a boundary line of maximum yield that decreased with increasing EC SH. In this semiarid system, EC SH-based management zones can be used in SSM of wheat for: (i) soil sampling to assess residual nutrients and soil attributes affecting herbicide efficacy, (ii) yield goal determination, and (iii) prescription maps for metering inputs.

1424. Cultivar * herbicide screening: 2002 results.

• Authors:
  • Littlewood, B.
  • Lemerle, D.
  • Lockley, P.
• Source: Cultivar * herbicide screening: 2002 results
• Year: 2003
• Summary: Results are presented of the evaluation of herbicide tolerance (based on yield performance) in wheat, barley, oat, triticale, rape, lupin, field pea, lentil, chickpea and faba bean cultivars and advanced lines grown in Wagga Wagga, New South Wales, Australia, during 2002. Compatibility charts of herbicide * cultivar combinations are included to provide guidelines to farmers on the relative risk of crop damage for various herbicide * cultivar combinations.

1425. Doubled haploid production in crop plants: a manual.

• Authors:
  • Kasha, K. J.
  • Maluszynski, M.
  • Forster, B. P.
  • Szarejko, I.
• Source: Doubled haploid production in crop plants: a manual
• Year: 2003
• Summary: This manual presents a set of protocols for the production of doubled haploid plants in 22 major crops species including 4 tree species, and includes protocols from different germplasm of the same species. The crops covered include barley, wheat, maize, rice, triticale, rye, oats, durum wheat, timothy grass ( Phleum pratense), ryegrass ( Lolium), rape, broccoli, tobacco, potato, flax/linseed, sugarbeet, asparagus, onion, apple, poplar, cork oak ( Quercus suber), and citrus. All steps of doubled haploid production are detailed from donor plant growth conditions, through in vitro procedures, media composition and preparation, to regeneration of haploid plants and chromosome doubling methods. The practical protocols are supplemented with a list of published protocols for other crop plants, and separate chapters deal with major application of doubled haploids in breeding, mutant production, transgenesis, genetic mapping and genomics.

1426. Winter Crop Variety Sowing Guide 2003.

• Authors:
  • McCaffery, D. W.
  • McRae, F. J.
  • Carpenter, D. J.
• Year: 2003
• Summary: This guide should assist in the selection of the most suitable variety for cultivation and aims to assist growers to make better cropping decisions. Information on variety selection, varietal characteristics and reaction to disease, crop injury guide and marketing are supplied for wheat, durum wheat, barley, oats, triticale, cereal rye, rape, chickpeas, faba beans, field pea ( Pisum sativum) and lupins. Additional material includes information on options for control of stored products pests, cereal seed dressings, industry information, and locations of district agronomists.

1427. Weed control in winter crops 2003.

• Authors:
  • Dellow, J. J.
  • Francis, R. J.
  • Mullen, C. L.
  • McRae, F. J.
• Source: Weed control in winter crops 2003
• Year: 2003
• Summary: This publication, intended for use by New South Wales Agriculture (New South Wales, Australia), presents some guidelines on chemical weed control in fallows, wheat, barley, oats, rye, triticale, rape, safflower, lentil, linseed, lupin, chickpea, faba bean and field pea. Tabulated data on herbicides, along with application rates suggested for particular weed species, are included.

1428. Cereal grain and dockage identification using machine vision

• Authors:
  • Jayas, D. S.
  • Visen, N. S.
  • Paliwal, J.
  • White, N. D. G.
• Source: Biosystems Engineering
• Volume: 85
• Issue: 1
• Year: 2003
• Summary: Algorithms were written to extract a total of 230 features (51 morphological, 123 colour, and 56 textural) from the high-resolution images of kernels of five grain types [barley, Canada Western Amber Durum (CWAD) wheat, Canada Western Red Spring (CWRS) wheat, oats, and rye] and five broad categories of dockage constituents [broken wheat kernels, chaff, buckwheat, wheat spikelets (one to three wheat kernels inside husk), and canola (rapeseed with low erucic acid content in the oil and low glucosinolate content in the meal)]. Different feature models, viz. morphological, colour, texture, and a combination of the three, were tested for their classification performances using a neural network classifier. Kernels and dockage particles with well-defined characteristics (e.g. CWRS wheat, buckwheat, and canola) showed near-perfect classification whereas particles with irregular and undefined features (e.g. chaff and wheat spikelets) were classified with accuracies of around 90%. The similarities in shape and size of some of the particles of chaff and wheat spikelets with the kernels of barley and oats affected the classification accuracies of the latter, adversely. (C) 2003 Silsoe Research Institute. All rights reserved. Published by Elsevier Science Ltd.

1429. Report from the Danish working group on the co-existence of genetically modified crops with conventional and organic crops.

• Authors:
  • Ostergard, H.
  • Pedersen, S.
  • Kjellsson, G.
  • Holm, P. B.
  • Gylling, M.
  • Buus, M.
  • Boelt, B.
  • Andersen, S. B.
  • Tolstrup, K.
  • Mikkelsen, S. A.
• Source: DIAS Report, Plant Production
• Issue: 94
• Year: 2003
• Summary: The paper focuses on the possible sources of dispersal (cross pollination, seed dispersal, vegetative dispersal, dispersal by farming machinery, dispersal during handling and transport) from genetically modified crop production to conventional and organic production, the extent of dispersal and the need for control measures, and the possible control measures for ensuring the co-existence of genetically modified production with conventional and organic production systems. Specific sections are provided on the crops currently genetically modified in Denmark or likely to be within the next few years (oilseed rape, maize, beet, potatoes, barley, wheat, triticale, oats, rye, forage and amenity grasses, grassland legumes, field peas, faba beans and lupins, and vegetable seeds). Brief discussions on the legislation, seed production, monitoring and analytical methods used, and measures to ensure crop purity (such as reducing pollen dispersal, reducing seed dispersal, adopting cultural methods reducing pollen and seed dispersal) are also presented.

1430. Crop yields and wild oat control in northern Alberta cropping systems

• Authors:
  • Soon, Y. K.
  • O'Donovan, J. T.
  • Drabble, J. C.
  • Darwent, A. L.
  • Milis, P. F.
  • Clayton, G. W.
  • Rice, W. A.
• Source: Canadian Journal of Plant Science
• Volume: 83
• Issue: 1
• Year: 2003
• Summary: A study was conducted on the Agriculture and Agri-Food Canada Research Farm, Beaverlodge, Alberta, to compare nine cropping systems in relation to productivity and wild oat (Avena fatua L.) control. The nine cropping systems consisted of three crop rotations and three levels of banded N fertilizer. Each cropping system had its own regime of tillage and weed control. One of the rotations consisted of mechanical fallow, along with canola (Brassica rapa L.), barley (Hordeum vulgare L.) and wheat (Trificum aestivum L.), while the other two rotations consisted of the same annual crops, but with either flax (Linum usitatissimum L.) or red clover (Trifolium pratense L.) plowdown with partial fallow substituted for mechanical fallow. The three rates of banded N fertilizer were 0, 75 and 150% of recommended, based on soil tests and provincial recommendations. From 1991 to 1994, cropping systems with mechanical fallow and fall tillage after annual crops produced 24% higher total seed yields than cropping systems with no fall tillage after annual crops and either continuous annual crops or red clover plowdown. Increasing the rate of banded N fertilizer from 0 to 75% of recommended increased total crop seed yields but a further increase from 75 to 150% had no significant effect. Although cropping systems with mechanical fallow had an advantage over other cropping systems, the effect of crop sequencing and yearly weather conditions on total crop seed yields was greater than the effect of cropping systems. Wild oat populations varied greatly with year, but the ease of management was greater in cropping systems with the mechanical fallow than in other cropping systems. Wild oat density increased when diclofop or difenzoquat performed inadequately or when poor red clover establishment allowed populations to increase. Reductions in wild oat populations appeared to be largely due to the consistent effectiveness of sethoxydim.