scholarly journals Pasture nematodes: the major scourge of white clover

2000 ◽  
pp. 195-199 ◽  
Author(s):  
R.N. Watson ◽  
C.F. Mercer
Keyword(s):  
White Clover ◽  
Management Practices ◽  
Research Programme ◽  
N Fixation ◽  
Production Potential ◽  
Pasture Production ◽  
Plant Feeding ◽  
Nitrogen Inputs ◽  
The Impact ◽  
Selection Of

This paper reviews current research within AgResearch to reduce the impact of plant-feeding nematodes. Plant-feeding nematodes reduce pasture production by around 15% annually, mainly through their effect on white clover. Nematicide application increases clover yields in pasture by an average 40% and N-fixation levels by over 50%. The problem occurs nationally. When pasture nematode burdens are reduced in established or newly sown ryegrass-white clover pasture, white clover can generally assume dominance during periods of active plant growth. The impact of clover nematodes in reducing nitrogen inputs and forage quality is estimated to exceed $1 billion annually in lost production potential. A gain of 1% in clover performance applied nationally is estimated to be worth up to $48 million. The research programme on pasture nematodes conducted within AgResearch has included evaluation of management practices that may reduce nematode impacts, selection of white clover seedlines for resistance or tolerance to nematodes, and identification of agents for biological control of nematodes within New Zealand pastures. Keywords: clover nematodes, Heterodera trifolii, impacts, Meloidogyne trifoliophila, M. hapla, Pratylenchus spp., Trifolium repens

scholarly journals Biomass Production and Potential Fixed Nitrogen Inputs from Leguminous Cover Crops in Subtropical Avocado Plantations

Agronomy ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 70
Author(s):  
Terry J. Rose ◽  
Lee J. Kearney
Keyword(s):  
Biomass Production ◽  
White Clover ◽  
Cover Crops ◽  
Persea Americana ◽  
N Fixation ◽  
N Losses ◽  
N Accumulation ◽  
Tree Crop ◽  
Nitrogen Inputs ◽  
Legume Cover Crops

Nitrogen (N) fertiliser is applied to perennial horticultural crops to increase yields, but subsequent N losses in subtropical plantations may be high due to intense rainfall and warmer temperatures. While legume cover crops could potentially contribute N to the tree crops and reduce fertiliser-N requirements, few studies have quantified potential fixed-N inputs from cover crops legumes in tropical or subtropical tree crop systems. To address this, we investigated growth and N fixation of summer-growing Pinto peanut (Arachis pintoi Krapov. & W. C. Greg cv. Amarillo) and winter/spring dominant white clover (Trifolium repens L. cv. Haifa) grown as a mixed species cover crop in two commercial subtropical avocado (Persea americana Mill. cv. Hass) plantations. Legume biomass was assessed prior to mowing of the inter-row (fortnightly in summer and every 6–8 weeks over winter) and N fixation was estimated using the 15N natural abundance technique. Biomass production was 7377 kg ha−1 (930 kg ha−1 for white clover and 6447 kg ha−1 for Pinto peanut) at the first site over the 14-month period from December 2014 to January 2016, and 4467 kg ha−1 (1114 kg ha−1 for white clover and 3353 kg ha−1 for Pinto peanut) at the second site over the same period. Estimation of N fixation was not possible at the first site, due to a lack of difference in isotopic discrimination between the legume shoots and the reference plant (kikuyu (Pennisetum clandestinum Chiov.)) material. While legume shoots accumulated 157 kg N ha−1 (38 kg ha−1 for white clover and 119 kg ha−1 for Pinto peanut) across the season at site 1, the % N derived from atmosphere (%Ndfa) in legumes was relatively low (50–60% in Pinto peanut during the warmer months and around 30% in autumn and early spring, and from 13 % in April to 69% in September for white clover). The low %Ndfa in the legumes may have been due to low rainfall or molybdenum (Mo) deficiency. Ultimately the legume cover crops contributed an estimated 50 kg fixed N ha−1, which could partially offset fertiliser N requirements of the tree crop. Our results demonstrate the need to quantify N fixation in legume cover crops to assess potential N benefits as opposed to relying on typical measurements of legume biomass and N accumulation.

scholarly journals Assessment of Main Cereal Crop Trade Impacts on Water and Land Security in Iraq

Agronomy ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 98 ◽  
Author(s):  
Salam Hussein Ewaid ◽  
Salwan Ali Abed ◽  
Nadhir Al-Ansari
Keyword(s):  
Water Resource Management ◽  
Management Practices ◽  
Water Footprint ◽  
Irrigation Management ◽  
Virtual Water ◽  
Cereal Crops ◽  
Scarce Water ◽  
The Impact ◽  
Selection Of ◽  
Resources Assessment

Growing populations, socio-economic development, the pollution of rivers, and the withdrawal of fresh water are all signs of increasing water scarcity, and with 85% of global use, agriculture is the biggest freshwater user. The water footprint (WF) and virtual water (VW) are concepts used recently for freshwater resources assessment. The WF reflects how much, when and where the water was used whereas VW reveals the volume of water embedded in goods when traded. The first goal of this research is to determine the WF per ton and the WF of production (Mm3/yr) of wheat, barley, rice, and maize in Iraq. The second goal is estimating the quantities of the 4 main cereal crops imported into Iraq and assessing the impact on reducing WF and land savings for 10 years from 2007 to 2016. The results showed that the WF per ton was 1736, 1769, 3694, 2238 m3/ton and the WF of production was 5271, 1475, 997, 820 Mm3/yr for wheat, barley, rice, and maize, respectively. The median total VW imported was 4408 Mm3/yr, the largest volume was 3478 Mm3/yr from wheat, and Iraq saved about 2676 Mm3 of irrigated water and 1,239,539 M ha of land by importing crops every year during 2007–2016. The study revealed the significance of better irrigation management methods to decrease the WF through a selection of crops that need less water and cultivation in rain-fed areas, as well as the use of cereal import to conserve scarce water resources, which is crucial both in terms of water resource management and preservation of the environment. The results of this research could be used as a guideline for better water management practices in Iraq and can provide helpful data for both stakeholders and policymakers.

Impact of insect root herbivory on the growth and nitrogen and carbon contents of white clover (Trifolium repens) seedlings

1996 ◽  
Vol 74 (10) ◽  
pp. 1591-1595 ◽  
Author(s):  
P. J. Murray ◽  
D. J. Hatch ◽  
J. B. Cliquet
Keyword(s):  
Root Exudates ◽  
White Clover ◽  
Trifolium Repens ◽  
Sequential Sampling ◽  
Sand Culture ◽  
N Fixation ◽  
Total N ◽  
Nitrogenous Compounds ◽  
Root Herbivory ◽  
The Impact

The impact of root herbivory by larvae of the weevil Sitona flavescens (Marsh.) on the growth and carbon and nitrogen economies of seedlings of white clover (Trifolium repens L.) and the nature and extent of nitrogenous compounds found in the root exudates taken from the rhizosphere were investigated. The seedlings were grown in sand culture in a system of microlysimeters that enabled sequential sampling of root exudates. Weevil infestation significantly reduced foliar biomass and total N and C contents and impaired N-fixation. The C:N ratios of the infested plants were significantly increased compared with those of uninfested seedlings. The most abundant amino acids in the exudates were aspartic acid and serine. Keywords: nitrogen fixation, Sitona spp., root exudates, white clover.

Comparison of a herbal ley with a ryegrass-white clover pasture and pure ryegrass sward receiving fertiliser nitrogen

1991 ◽  
pp. 225-230 ◽  
Author(s):  
B.E. Ruz-Jerez ◽  
P.Roger Ball ◽  
R.E. White ◽  
P.E.H. Gregg
Keyword(s):  
White Clover ◽  
Symbiotic Nitrogen Fixation ◽  
Total Yield ◽  
Red Clover ◽  
N Fixation ◽  
Botanical Composition ◽  
Forage Legumes ◽  
Pasture Production ◽  
Intensively Managed ◽  
Intensive System

This paper compares a herbal ley (of particular interest to farmers involved in the 'organic' branch of agriculture) with a conventional pasture (ryegrass-white clover) and a more intensive system (pure ryegrass receiving 400 kg fertiliser N/ha/yr) in a study lasting 2 years. The herbal ley seeds mixture was prepared following the pioneering ideas of Robert Elliot in his "Clifton ~~ ~~~~~Park"mixture,-whichbasically-included~a-group of 'non-aggressive' grasses, forage legumes and herbs. Pasture production (average of 2 years) from Herbal ley was 15 t DM/ha/yr, representing approximately 90% of the yield from the intensively managed pure ryegrass pasture receiving 400 kg N/ ha&r and some 2530% more than from ryegrassclover. A major feature of the herbal ley was substantialproductionduringlate.springandsummer, when chicory (the most dominant herb), and red clover and white clover made a major contribution to herbage yield. In winter the total yield was similar tothatI?omthegrass-cloverpasture.L.egumecontent was 23 and 3 1% (averaged over the year) for Grassclover and Herbal ley pastures respectively. In spite of this difference, symbiotic N fixation was similar. So fixation efficiency on a legume yield basis was 50.3 and 3 1.6 kg N fixed/t legume DM harvested, respectively. These results could reflect a different pattern of utilisation of soil N, as a consequence of the different botanical composition of the swards. In summary, the performance of the herbal ley offers the promise of an alternative, 'specialist' pasture and would be highly beneficial if quality feed is required in summer. Keywords herbal ley, biological fertility, nitrogen, symbiotic nitrogen fixation, pasture mixtures

scholarly journals THE EFFECT OF GRASS GRUB ON THE HERBAGE PRODUCTION OF DIFFERENT PASTURE SPECIES IN THE PUMICE COUNTRY

1979 ◽  
pp. 105-115 ◽  
Author(s):  
R. East ◽  
W.M. Kain ◽  
J.A. Douglas
Keyword(s):  
White Clover ◽  
Tall Fescue ◽  
Pasture Production ◽  
Prairie Grass ◽  
Small Plot ◽  
Low Levels ◽  
The Impact

Small plot mowing trials carried out on central North Island pumice soils have shown that Huia white clover and SI70 tall fescue support high grass grub populations, while the resistant legumes Wairau lucerne and Maku Lotus pedunculayus suppress grass grub numbers to low levels. Measurement of the effects of grass grub on herbage production has highlighted both the susceptibility of white clover, Nui and Ruanui ryegrasses, and browntop to grass grub attack, and the potential of highly productive resistant or tolerant specres (lucerne, tall fescue and to a lesser extent Apanui cocksfoot and Matua prairie grass) for lessening the impact of grass grub on pasture production in this region.

scholarly journals Forecast Terminology: Composition and Interpretation of Public Weather Forecasts2,3

1983 ◽  
Vol 64 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Allan H. Murphy ◽  
Barbara G. Brown
Keyword(s):  
Management Practices ◽  
Public Understanding ◽  
Training And Education ◽  
Weather Forecasts ◽  
Weather Information ◽  
Level Of Understanding ◽  
Verification Systems ◽  
The Impact ◽  
Selection Of

Worded forecasts, which generally consist of both verbal and numerical expressions, play an important role in the communication of weather information to the general public. However, relatively few studies of the composition and interpretation of such forecasts have been conducted. Moreover, the studies that have been undertaken to date indicate that many expressions currently used in public forecasts are subject to wide ranges of interpretation (and to misinterpretation) and that the ability of individuals to recall the content of worded forecasts is quite limited. This paper focuses on forecast terminology and the understanding of such terminology in the context of short-range public weather forecasts. The results of previous studies of forecast terminology (and related issues) are summarized with respect to six basic aspects or facets of worded forecasts. These facets include: 1) events (the values of the meteorological variables): 2) terminology (the words used to describe the events); 3) words versus numbers (the use of verbal and/or numerical expressions); 4) uncertainty (the mode of expression of uncertainty); 5) amount of information (the number of items of information); and 6) content and format (the selection of items of information and their placement). In addition, some related topics are treated briefly, including the impact of verification systems, the role of computer-worded forecasts, the implications of new modes of communication, and the use of weather forecasts. Some conclusions and inferences that can be drawn from this review of previous work are discussed briefly, and a set of recommendations are presented regarding steps that should be taken to raise the level of understanding and enhance the usefulness of worded forecasts. These recommendations are organized under four headings: 1) studies of public understanding, interpretation, and use; 2) management practices; 3) forecaster training and education; and 4) public education.

scholarly journals Management of clover in grazed pastures: expectations, limitations and opportunities

1996 ◽  
Vol 6 ◽  
pp. 55-64
Author(s):  
D.F. Chapman ◽  
A.J. Parsons ◽  
S. Schwinning
Keyword(s):  
White Clover ◽  
Nutritive Value ◽  
Self Regulation ◽  
Daily Intake ◽  
Metabolic Efficiency ◽  
N Fixation ◽  
N Availability ◽  
Intake Rate ◽  
Nitrogen Inputs ◽  
Clover Content

The value of white clover as a component of New Zealand pastures is undeniable, but it is also widely recognised that clover has limitations as a pasture plant and that these can lead to inefficiencies in the performance of grass/clover associations. This paper identifies some of the limitations to optimising the contribution of clover in complex soil/pasture/animal systems, within the context of the expectations commonly held of clover. Limitations to exploiting the greater digestive efficiency and short-term intake rate of clover compared to grass when they are grown in a mixture include animal behaviour responses that sometimes impose a restriction on total daily intake of nutrients, and the fact that clover often constitutes less than 20% of the pasture. Nitrogen inputs and yield advantages are also restricted by the low clover content of pastures. A simulation model is used to analyse the co-existence of grass and clover as influenced by N dynamics. This model explains the basis for selfregulation by grass/clover mixtures of the amount of mineral N in the soil. Self-regulation minimises N losses from mixtures, but the dynamic response of grass and clover to N availability also means that there may only be limited scope for increasing the overall clover content, or decreasing the spatial heterogeneity in clover distribution, of a mixture. Managing grass/clover associations to realise the benefits of white clover therefore means manipulating a complex system, where the outcomes of manipulation depend as much on the response of the companion grass as on the response of the clover itself. Opportunities for attaining a higher clover content in pastures include: manipulating the preferences of animals for clover versus grass; spatially separating grass and clover within fields; increasing the metabolic efficiency of N fixation in clover; uncoupling the apparent link between rhizobium symbiosis and the N content of clover leaves; and modifying the stolon morphology of clover as a way of increasing clover presence in favourable microsites within the pasture. Keywords: genetic improvement, grass/clover competition, grazing behaviour, intake, models, N fixation, nitrogen dynamics, nutritive value

scholarly journals The impact of farming without nitrogen fertiliser for ten years on pasture yield and composition, milksolids production and profitability; a research farmlet comparison

2013 ◽  
pp. 71-78 ◽  
Author(s):  
C.B. Glassey ◽  
C.G. Roach ◽  
J.M. Lee ◽  
D.A. Clark
Keyword(s):  
White Clover ◽  
Stocking Rate ◽  
Pasture Production ◽  
Nitrogen Fertiliser ◽  
The Impact ◽  
Pasture Yield

Two experimental farmlets were established in the 2001/02 season and run continuously to 2010/11, comparing the impact of two nitrogen (N) fertiliser systems on milksolids (MS) production, profitability and the yield and composition of ryegrass-white clover pastures. Treatments were: 1) No-N. No N fertiliser applied, stocking rate 2.56 cow equivalents/ha (including replacements); 2) Control. Average of 181 kg N/ha/year applied as urea, stocking rate 3.06 cows/ ha (replacements grazed off farm). Annual pasture production was, on average, 2.9 t DM/ha greater on the Control farmlet compared with the No-N farmlet (P

The Role and Characteristics of Hybrid Approaches to Project Management in the Development of Technology-Based Products and Services

2020 ◽  
pp. 875697282095688
Author(s):  
Flávio Copola Azenha ◽  
Diane Aparecida Reis ◽  
André Leme Fleury
Keyword(s):  
Project Management ◽  
Management Practices ◽  
Service Development ◽  
Management Approach ◽  
Advantages And Disadvantages ◽  
Hybrid Approaches ◽  
Develop Technology ◽  
Multiple Case ◽  
The Impact ◽  
Selection Of

There is a trend of combining agile and traditional project management practices for technology-based product and service development in the search for more agility. Although there are, in the literature, hybrid models that propose combinations of traditional and agile approaches, there are no studies that discuss the impact of the adoption of this approach in organizations in practice. Consequently, guidance on the selection of the most appropriate project management approach has remained largely theoretical, rather than based on companies’ experiences. The objective of this research is to analyze how organizations that develop technology-based products and services apply hybrid approaches to project management, their characteristics, advantages, and disadvantages, conducting a literature review and multiple case studies as research methods. Results reveal that hybrid approaches to project management are currently fundamental for companies in order to deal with distinct organizational cultures, specific processes, customer contractual requirements, and project specificities. This study also led to a consolidated list of the characteristics of hybrid approaches to project management.

The influence of stocking rate and mixed grazing of Angora goats and Merino sheep on animal and pasture production in southern Australia. 4. Gastrointestinal parasitism

2014 ◽  
Vol 54 (5) ◽  
pp. 587 ◽  
Author(s):  
B. A. McGregor ◽  
P. J. A. Presidente ◽  
N. J. Campbell
Keyword(s):  
Management Practices ◽  
Gastrointestinal Nematode ◽  
Gastrointestinal Nematodes ◽  
Stocking Rate ◽  
Sources Of Information ◽  
Pasture Production ◽  
Merino Sheep ◽  
Sheep And Goats ◽  
Gastrointestinal Parasitism ◽  
The Impact

Gastrointestinal nematodes limit the growth, production and welfare of goats but there are few reliable sources of information for recommending management practices across flocks. The effects of animal species (Angora goat, Merino sheep, mixed-grazed goats and mixed-grazed sheep at the ratio of 1 : 1) and stocking rate (SR: 7.5, 10, 12.5 animals/ha) on gastrointestinal parasitism were determined in a replicated experiment on improved annual temperate pastures in southern Australia, from 1981 to 1984. Detailed monitoring of gastrointestinal nematodes was undertaken on animals before, during (five times per year) and at the conclusion of studies using faecal strongyle egg counts (WEC) and total worm counts. Sheep had a greater proportion of nematodes as Teladorsagia spp. and goats a greater incidence of Trichostrongylus spp. Both goats and sheep developed resistance to Nematodirus spp. during the experiment. WEC was similar in goats and sheep at the start of the experimental period but, thereafter, was consistently greater in goats than in sheep. While WEC was highly related to total worm count, the regressions for sheep and goats were different. Increasing the SR increased the WEC of goats and mixed-grazed goats but not of sheep. During the experiment, WEC declined at 7 and 10 animals/ha but increased at 12.5/ha. Mixed grazing with goats provided beneficial effects for sheep at all stocking rates, but the effects for goats were dependent on the stocking rate, being beneficial at 7.5 and 10/ha but harmful at 12.5/ha. The WEC of separately grazed goats were generally higher than the WEC of mixed grazed goats. The WEC of mixed sheep were lower than those of separately grazed sheep. During the experiment, the WEC of mixed grazed sheep declined faster than the WEC of separately grazed sheep but the WEC of separately grazed goats at 12.5/ha and of mixed grazed goats at 10 and 12.5/ha increased. Under the environmental and pastoral conditions examined, Angora wether goats should not be grazed at SR above those recommended for wether sheep. In the present study, the impact of gastrointestinal-nematode infections in goats was reduced at lower SR. Further, mixed grazing of Angora wether goats with wether sheep at or below the recommended SR resulted in reduced gastrointestinal parasitism for both sheep and goats, compared with monospecific grazing conditions. Goats did not represent a gastrointestinal-nematode hazard to sheep.

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