Relationship of rainfall, cultural practices, soil and plant nutrients, and seedling survival with root disease and parasitic nematode numbers in annual Medicago spp. Pastures

1999 ◽  
Vol 50 (6) ◽  
pp. 977 ◽  
Author(s):  
M. P. You ◽  
I. T. Riley ◽  
K. Sivasithamparam ◽  
M. J. Barbetti
Keyword(s):  
Root Rot ◽  
Lateral Root ◽  
Cultural Practices ◽  
Seedling Survival ◽  
Root Disease ◽  
Plant Nutrients ◽  
Tap Root ◽  
Low Levels ◽  
Annual Medicago ◽  
Relationship Of

Surveys were conducted for annual Medicago spp. (medic) pastures in the grain belt of south-west Western Australia during spring 1996 and winter–spring 1997 to determine the relationship of rainfall, cultural practices, soil and plant nutrients, and seedling survival with severity of root disease and numbers of parasitic nematodes. Medic pasture was sampled on 116 farms. Most pastures consisted of a single medic variety, viz. Serena, Santiago, Cyprus, or Caliph, whereas about 33% of sites had mixed varieties. Regression analyses showed that high rainfall and application of phosphorus fertilisers were correlated with increased severity of rot in medic tap roots. Crop history and medic variety were not related to the level of root rot. Numbers of Pratylenchusin medic roots were not correlated with the level of tap or lateral root rot, medic variety, rainfall, or with the application of insecticide, fertilisers, or herbicides. Soil with relatively high levels of P, NO3-, or Fe was associated with an increased level of tap root rot. Soils with high pH were associated with reduced tap root rot. Soils with relatively high K were related to severe lateral root rot, whereas relatively high levels of P in soil were associated with reduced lateral root rot. Plants with high levels of tap root rot showed low levels of Mg, whilst low levels of Ca and NO3– in tissues were related to high levels of lateral root rot. High levels of tap root rot were associated with relatively high levels of total N, K, and S, Cu, Zn, Mn, and NO3- in plant tissues. Plants with relatively high levels of lateral root rot had relatively high levels of Cu in shoots. Of the 116 annual Medicago pastures sampled, only 1% had adequate Mg content and only 19% had adequate Ca content. However, 83% had higher than adequate levels of Cu, 70% had higher than adequate levels of Mn, and all samples showed more than adequate levels of chloride. Experimental sites of M. polymorpha cv. Serena at 6 farms showed that the percentage survival rate of seedlings was negatively correlated with the severity of tap and lateral root rot in the previous year. These results indicate that in the farms surveyed there is a serious threat to annual medic pastures from root rot fungi. The severity of the disease was partly determined by soil conditions and cultural practices.

Effect of clover-free rotations upon the severity of root rot and yield in regenerating subterranean clover pastures

1991 ◽  
Vol 42 (7) ◽  
pp. 1195 ◽  
Author(s):  
MJ Barbetti
Keyword(s):  
Seed Yield ◽  
Root Rot ◽  
Lateral Root ◽  
Subterranean Clover ◽  
Complete Removal ◽  
Plant Size ◽  
Field Trials ◽  
Root Disease ◽  
Variable Effect ◽  
Tap Root

In two field trials, complete removal of subterranean clover for one season, or in particular two seasons, significantly reduced tap and lateral root disease in the immediate following year in which subterranean clover was allowed to regenerate. By the second season of regeneration these effects were either small or absent. Subterranean clover removal had greater effect on reducing lateral root disease than tap root disease in regenerating pastures. There were often large increases in plant size in regenerating pastures following complete removal of subterranean clover for one season or, in particular, two consecutive seasons. This effect also persisted poorly beyond the first season of regeneration. The losses in terms of subterranean clover herbage and seed yield during the period of subterranean clover removal were not offset by subsequent benefits from root disease reductions, as there was no corresponding increase in total herbage production. Subterranean clover removal had a variable effect upon the per cent subterranean clover v. grass ratio in regenerating pastures. Removal of subterranean clover for short periods (1 or 2 years) as an agronomic practice does not appear to be useful in overcoming root rot problems associated with this species in the high (> 750 mm) rainfall zone, the zone where severe root rot most frequently occurs in Western Australia.

Severity of root rot in mature subterranean clover and associated fungal pathogens in the wheatbelt of Western Australia

2009 ◽  
Vol 60 (1) ◽  
pp. 43 ◽  
Author(s):  
Tiernan A. O'Rourke ◽  
Tim T. Scanlon ◽  
Megan H. Ryan ◽  
Len J. Wade ◽  
Alan C. McKay ◽  
...  
Keyword(s):  
Western Australia ◽  
Root Rot ◽  
Fungal Pathogens ◽  
Lateral Roots ◽  
Subterranean Clover ◽  
Growing Season ◽  
Root Diameter ◽  
Root Disease ◽  
Soil Dna ◽  
Tap Root

Pasture decline is considered to be a serious challenge to agricultural productivity of subterranean clover across southern Australia. Root disease is a significant contributing factor to pasture decline. However, root disease assessments are generally carried out in the early part of the growing season and in areas predominantly sown to permanent pastures. For this reason, in spring 2004, a survey was undertaken to determine the severity of root disease in mature subterranean clover plants in pastures located in the wheatbelt of Western Australia. DNA-based soil assays were used to estimate population density in the soil of a variety of soil-borne pathogens known to commonly occur in the Mediterranean-type environments of southern Australia. The relationships between severity of disease on tap and lateral roots and root diameter, root length, nodulation, and total rainfall were determined. The survey showed, for the first time, that severe root disease is widespread in spring across the wheatbelt of Western Australia. There was a positive correlation between rainfall and tap root disease, and between tap root disease and average root diameter of the entire root system. Despite the high levels of root disease present across the sites, the DNA of most root disease pathogens assayed was detected in trace concentrations. Only Pythium Clade F showed high DNA concentrations in the soil. DNA concentrations in the soil, in particular for Phytophthora clandestina and Rhizoctonia solani AG 2.1 and AG 2.2, were higher in the smaller autumn sampling in 2006. This study suggests that the productivity of subterranean clover-based pastures is severely compromised by root rot diseases throughout the growing season in the wheatbelt of Western Australia.

Effects of trifluralin, benomyl and metalaxyl on the incidence and severity of root disease in annual Medicago spp., and evaluation of cultivars for resistance to root rot

1986 ◽  
Vol 26 (1) ◽  
pp. 65 ◽  
Author(s):  
TW Bretag ◽  
JF Kollmorgen
Keyword(s):  
Biological Activity ◽  
Root Rot ◽  
Dry Matter ◽  
Root Disease ◽  
Infested Soil ◽  
Field Observations ◽  
Root Diseases ◽  
Matter Production ◽  
Annual Medicago ◽  
Moderate Resistance

The herbicide trifluralin increased both the incidence and severity of root rot in four Medicago truncatula cultivars and reduced their dry matter production. In glasshouse studies with a naturally infested soil from Kaniva, medic root disease was controlled by soil incorporation of metalaxyl but not by soil treatment with benomyl. The known biological activity of metalaxyl suggests that the fungi responsible for the root rot were Peronosporales. The same fungicides failed to control medic root diseases in a field trial at Dooen in 1984. Medic cultivars varied in their susceptibility to root rot, some having moderate resistance, although none were immune. The susceptibility rankings established in glasshouse tests with naturally infested soil were supported by field observations. The results show that there is potential for control of medic root diseases by selecting resistant medic cultivars.

Relation between plant size and severity of root rot in subterranean clover

1983 ◽  
Vol 23 (121) ◽  
pp. 126
Author(s):  
MJ Barbetti
Keyword(s):  
Root System ◽  
Western Australia ◽  
Root Rot ◽  
Lateral Root ◽  
Inverse Relationship ◽  
Subterranean Clover ◽  
Plant Size ◽  
Tap Root ◽  
The Relationship

Investigations were carried out in south-western Western Australia in 1977-78 to assess the relationship between dry weights of subterranean clover tops and roots and the severity of root rot. An inverse relationship was established between the severity of rotting of the tap root system and the plant top and the root dry weights. There was no relationship between the severity of root rot of the lateral root system and the plant top and root dry weights.

Amelioration of root disease of subterranean clover (Trifolium subterraneum) by mineral nutrients

2012 ◽  
Vol 63 (7) ◽  
pp. 672 ◽  
Author(s):  
Tiernan A. O'Rourke ◽  
Megan H. Ryan ◽  
Tim T. Scanlon ◽  
Krishnapillai Sivasithamparam ◽  
Martin J. Barbetti
Keyword(s):  
Nutrient Solution ◽  
Lateral Root ◽  
Field Experiments ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Mineral Nutrients ◽  
Root Disease ◽  
Tap Root ◽  
Complete Nutrient Solution

Subterranean clover (Trifolium subterraneum) is a key pasture legume across southern Australia and elsewhere. Decline in subterranean clover pastures was first recognised in Australia during the 1960s and manifests as an increase in weeds and a decrease in desirable legume species. While both root disease and poor nutrition contribute to subterranean clover pasture decline, the relationships between root disease and nutrition have not been determined. The objective of this study was to define these relationships. Field experiments were undertaken to determine the nutritional and pathogen status of soils and subterranean clover from three Western Australian field sites. Subsequently, controlled environment experiments were undertaken to determine the relative severities of tap and lateral root disease and growth of plants when soil cores taken from these three field sites were amended with a complete nutrient solution or a range of individual macro- or micronutrient treatments. Application of a ‘Hoaglands’ complete nutrient solution decreased the severity of tap root disease by an average of 45% and lateral root disease by 32%. Amendment with K alone reduced the severity of tap root disease an average of 32%; while the application of N alone reduced the severity of tap root disease by 33% and lateral root disease by 27%. Application of Hoaglands, K, N or Zn increased shoot and root dry weight, while Mo only increased shoot dry weight. This is the first report to show that mineral nutrients can substantially ameliorate root disease in subterranean clover. The results demonstrate that while root disease limits plant growth, improvement in the nutritional status of nutrient-impoverished soils can significantly reduce root disease. There is significant potential to incorporate nutrient amendments into an integrated and more sustainable approach to better manage root disease and to increase productivity of pasture legumes where soils are inherently nutrient deficient in one or more nutrients.

Effects of cultivation and cultural practice on root rot of subterranean clover

1984 ◽  
Vol 24 (127) ◽  
pp. 550 ◽  
Author(s):  
MJ Barbetti ◽  
GC MacNish
Keyword(s):  
Western Australia ◽  
Root Rot ◽  
Lateral Root ◽  
Field Experiments ◽  
Cultural Practices ◽  
Subterranean Clover ◽  
Cultural Practice ◽  
Second Year

Field experiments in 1975 and 1976 in south-western Western Australia investigated the effects of various cultivation and cultural practices on the level of root rot of subterranean clover. The treatments produced significant reductions in the levels of both tap and lateral root rot, but these reductions failed to persist beyond the second year after treatment. The best treatments were those of fallowing an area from August to March before cultivation and reseeding, or spring cultivation before sowing to oats followed by a March cultivation and reseeding.

HYPOGAMMAGLOBULINEMIA

PEDIATRICS ◽  
1960 ◽  
Vol 26 (5) ◽  
pp. 817-821
Author(s):  
Thomas F. Dolan ◽  
Norman B. McCullough ◽  
Lewis E. Gibson
Keyword(s):  
Antibiotic Therapy ◽  
Gamma Globulin ◽  
Nocardia Asteroides ◽  
Recurrent Infections ◽  
Salmonella Newport ◽  
Low Levels ◽  
Relationship Of ◽  
The Relationship

An unusual patient, characterized by recurrent infections, hepatosplenomegaly, low levels of gamma-globulin in the serum (400 mg/100 ml) and lymphocytosis, is described. The patient had pneumonia due to Nocardia asteroides followed by chronic Salmonella newport infection of 16 months' duration, kept in check by continuous antibiotic therapy. No antibodies were produced against specific antigenic challenges. The relationship of this case to those of congenital and acquired agammaglobulinemia is discussed.

scholarly journals Landslides and the Urban Forest

2011 ◽  
Vol 37 (5) ◽  
pp. 213-218
Author(s):  
Robert Loeb ◽  
Samuel King
Keyword(s):  
Root System ◽  
Lateral Root ◽  
Urban Forest ◽  
Basal Area ◽  
Natural Area ◽  
Species Classification ◽  
Slope Steepness ◽  
Tap Root ◽  
Area Survey ◽  
Root Plate

Trees and saplings were felled and killed by rockslides and soil slides formed during the record breaking rains of May 1–2, 2010, in Radnor Lake State Natural Area, Nashville, Tennessee, U.S. The losses were analyzed by species; stem basal area; root plate diameter and depth; percent slope; occurrence in a rockslide or soil slide as well as species classification as a lateral root system species versus tap or heart root system species. The number of stems lost for each species had a distribution similar to the results of the 2009 Natural Area survey but the number of saplings was significantly underrepresented at the landslide sites. Tree deaths were nearly five times greater than saplings lost. Although there were nearly equal numbers of tree and sapling stems classified as possessing a lateral root system versus tap or heart root system, 74% of the sapling losses were from surface root system species. The means for root plate diameter and depth were significantly larger in rockslides than soil slides even though the mean stem basal area did not differ significantly. For both slide types, slope steepness was not correlated with root plate depth, root plate diameter, or stem basal area. Similarly for both root system classi-fications, slope steepness was not significantly correlated except for surface root system trees with root plate depth. Planting tap root system trees reduces the risk of landslide, but advances in the cultivation of taxa, such as hickory (Carya spp.), are needed to assure tap root preservation during transplantation.

scholarly journals Comparison between Steiner cephalometric and modified Andrews photometric method for assessing antero-posterior position of the maxillary central incisors.

2019 ◽  
Vol 147 (11-12) ◽  
pp. 670-675
Author(s):  
Predrag Vucinic ◽  
Djordje Petrovic ◽  
Stojan Ivic ◽  
Sanja Vujkov
Keyword(s):  
Vertical Line ◽  
Photometric Method ◽  
Facial Features ◽  
Tooth Position ◽  
Facial Esthetics ◽  
Lateral Cephalograms ◽  
Significant Difference ◽  
Low Levels ◽  
Relationship Of ◽  
Posterior Position

Introduction/Objective. Maxillary incisors, when exposed during smile, are one of the most important facial features. In an attempt to overcome limitations of standard cephalometric methods, Andrews described an approach to determine ideal anteroposterior (AP) position of maxillary central incisors in smiling profile in relation to the forehead. We compared traditional Steiner cephalometric method, using surrounding skeletal landmarks, to the method proposed by Andrews, with the aim of determining whether distant but very noticeable craniofacial structures can affect our impression of tooth position. Methods. The study comprised 90 randomly selected lateral cephalograms, divided into three groups according to maxillary central incisors AP position according to Steiner cephalometric norms. The AP relationship of the maxillary central incisors was measured as a perpendicular distance from facial axis point to the nasion A line and to the vertical line through forehead facial axis point respectively. Student?s t-test and Pearson?s correlation were used to compare tested variables. Results. There was statistically significant difference between two methods (p = 0.01108). According to the Steiner method 46.67% subjects had retrusive incisors and 53.33% subjects had protrusion. Andrews?s method showed different results; 35.56% subjects had retrusion, while 64.4% had protrusion. Conclusion. The method proposed by Andrews showed consistently more protrusion than the traditional cephalometric method according to Steiner. Slightly retruded position of maxillary central incisors according to Steiner analysis does not always imply poor facial esthetics, if they have favorable position to the forehead. Low levels of correlation indicate that we should never rely on just one set of parameters.

Screening for Iron Deficiency with the Erythrocyte Protoporphyrin Test

PEDIATRICS ◽  
1983 ◽  
Vol 72 (2) ◽  
pp. 214-219
Author(s):  
Ray Yip ◽  
Samuel Schwartz ◽  
Amos S. Deinard
Keyword(s):  
Iron Deficiency ◽  
Serum Ferritin ◽  
Whole Blood ◽  
Ferritin Level ◽  
Lead Toxicity ◽  
Normal Serum ◽  
Erythrocyte Protoporphyrin ◽  
Age Related ◽  
Low Levels ◽  
Relationship Of

Elevation of erythrocyte protoporphyrin (EP) level is one of the consequences of iron deficiency. As the EP test has been established to be a screening test for lead poisoning, the screening capability of the EP test for iron deficiency was investigated. A total of 4,160 children between ages 6 months to 12 years had EP determined together with serum ferritin and hematocrit. Comparing the relationship of EP to serum ferritin and using a serum ferritin value ≤15 µg/L as the criterion of iron deficiency, the optimal cutoff limit for the EP test appears to be 35 µg/dL of whole blood. At this level, 88% of the subjects with low levels of serum ferritin can be detected (sensitivity), in contrast to the 53% detected at a higher cutoff value (≥50 µg/dL) used to screen for lead toxicity, or to the 59% detected by age-related hematocrit value. At an EP screening level of 35 µg/dL of whole blood, 90% of the subjects with normal serum ferritin level are correctly determined to be screen negative (specificity). The predictive value of low levels of serum ferritin for all subjects above screening level is 38%. In general, an elevated EP level, by itself, represents inadequate iron supply for hematopoiesis and signals iron deficiency regardless of whether the serum ferritin value is below the diagnostic level or not. A trial course of orally administered iron is suggested for children who are found to have an elevated EP value, with an increase in hemoglobin or hematocrit value serving, retrospectively, as confirmation of prior iron deficiency.

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