Advantages of the Nitrogen-15 Dilution Technique for Field Measurements of Symbiotic Dinitrogen Fixation in Legumes

2015 ◽  
pp. 11-21 ◽  
Author(s):  
Donald A. Phillips ◽  
Milton B. Jones ◽  
Ken W. Foster
Keyword(s):  
Field Measurements ◽  
Dinitrogen Fixation ◽  
Dilution Technique

Étude de l'influence des réserves azotées dans l'estimation par 15N de la fixation symbiotique d'une plante pérenne, Trifolium pratense

1985 ◽  
Vol 63 (6) ◽  
pp. 991-994
Author(s):  
Chantal Lescure ◽  
Alain Chalamet
Keyword(s):  
Trifolium Pratense ◽  
Control Plant ◽  
Red Clover ◽  
Good Control ◽  
Dinitrogen Fixation ◽  
Dilution Technique ◽  
Trifolium Pratense L ◽  
Perennial Legumes ◽  
Kinetics Of

A 15N dilution technique is proposed to determine the role of nitrogen reserves in the plant on the estimation of dinitrogen fixation, during regrowth of perennial legumes. It is based on labelling of nitrogen compartments of the plant. Since the kinetics of utilization of nitrogen reserves of ryegrass (Lolium italicum L.) and red clover (Trifolium pratense L.) appear similar, ryegrass would be a good control plant. Despite this observation, the comparison of two methods (based on two or three sources of nitrogen) to estimate dinitrogen fixation shows the difficulty in applying the technique using 15N-labelled substrate over earlier periods of regrowth. In this case, the 15N method described for determining symbiotic dinitrogen fixation could be applied in controlled conditions.

Fibrinolysis in Obstetrical Coagulopathy

1961 ◽  
Vol 05 (01) ◽  
pp. 021-037 ◽  
Author(s):  
H Zilliacus
Keyword(s):  
Coagulation Factors ◽  
Clotting Factor ◽  
Foetal Death ◽  
Dilution Technique ◽  
Induced Labor ◽  
Blood Samples ◽  
Decidual Tissue ◽  
Obstetrics And Gynaecology ◽  
Obstetrical Management ◽  
Uterine Haemorrhage

SummaryIn the introduction it is stressed that in cases with normal blood coagulation and even in cases with a limited decrease of some of the coagulation factors, the contraction of the uterus after the passage of the placenta closes the vessel endings, thereby providing the conditions necessary for haemostasis through the clotting of the blood. In contrast to this, fibrinolytic uterine bleeding is a condition in which the clotting factor and clot are consumed despite adequate postpartum contraction of the uterus.The literature on obstetrical coagulopathies is briefly summarized.The incongruence in the clotting power of blood samples drawn simultaneously from a cubital vein and from the uterus in cases of severe uterine haemorrhage is pointed out.With the aid of a plasma-dilution technique (Schneider) for the estimation of fibrinogen and fibrinolysis it was shown that in 6 out of 8 investigated cases of premature separation of the placenta, in 4 out of 5 observed cases of longstanding intrauterine foetal death and in 2 cases of pitocin drip induced labor considerable fibrinolytic activity was present in the blood from the uterus, whereas only slight activity if any, could be observed in blood samples drawn simultaneously from a cubital vein. These observations are found to be in conformity with the finding of considerable amounts of fibrinolytic activators in myométrial, placental and decidual tissue reported by other authors.Figures for obstetrical cases (19,808 deliveries) and uterine haemorrhage during the 5-year period 1955—1959 at the 1st Department of Obstetrics and Gynaecology, University Central Hospital, Helsinki, Finland, are presented. The main principles of obstetrical management at this hospital are outlined, with special reference to uterine coagulopathic haemorrhage.

79. Comparison of Benzene-Specific Field Measurements at Oil Refineries

1999 ◽  
Author(s):  
W.R. Haag ◽  
P. Owens ◽  
D. Mayszak ◽  
J. Katona ◽  
B. Mangilin ◽  
...  
Keyword(s):  
Field Measurements ◽  
Oil Refineries ◽  
Specific Field

An evaluation of a strategic de-stocking regime for dairying to improve nitrogen efficiency and reduce nitrate leaching from dairy farms in nitrate-sensitive areas

2000 ◽  
pp. 105-110
Author(s):  
Cecile De Klein ◽  
Jim Paton ◽  
Stewart Ledgard
Keyword(s):  
New Zealand ◽  
Nitrate Leaching ◽  
Management Practice ◽  
Field Measurements ◽  
Dairy Farms ◽  
Nitrogen Efficiency ◽  
Management Tool ◽  
Pasture Production ◽  
Leaching Losses ◽  
Sensitive Areas

Strategic de-stocking in winter is a common management practice on dairy farms in Southland, New Zealand, to protect the soil against pugging damage. This paper examines whether this practice can also be used to reduce nitrate leaching losses. Model analyses and field measurements were used to estimate nitrate leaching losses and pasture production under two strategic de-stocking regimes: 3 months off-farm or 5 months on a feed pad with effluent collected and applied back to the land. The model analyses, based on the results of a long-term farmlet study under conventional grazing and on information for an average New Zealand farm, suggested that the 3- or 5-month de-stocking could reduce nitrate leaching losses by about 20% or 35-50%, respectively compared to a conventional grazing system. Field measurements on the Taieri Plain in Otago support these findings, although the results to date are confounded by drought conditions during the 1998 and 1999 seasons. The average nitrate concentration of the drainage water of a 5-month strategic de-stocking treatment was about 60% lower than under conventional grazing. Pasture production of the 5-month strategic de-stocking regime with effluent return was estimated based on data for apparent N efficiency of excreta patches versus uniformlyspread farm dairy effluent N. The results suggested that a strategic de-stocking regime could increase pasture production by about 2 to 8%. A cost/ benefit analysis of the 5-month de-stocking system using a feed pad, comparing additional capital and operational costs with additional income from a 5% increase in DM production, show a positive return on capital for an average New Zealand dairy farm. This suggests that a strategic destocking system has good potential as a management tool to reduce nitrate leaching losses in nitrate sensitive areas whilst being economically viable, particularly on farms where an effluent application system or a feed pad are already in place. Keywords: dairying, feed pads, nitrate leaching, nitrogen efficiency, productivity, strategic de-stocking

A protocol for sampling pastures in hill country

2016 ◽  
Vol 78 ◽  
pp. 203-209 ◽  
Author(s):  
K.J. Hutchinson ◽  
D.R. Scobie ◽  
J. Beautrais ◽  
A.D. Mackay ◽  
G.M. Rennie ◽  
...  
Keyword(s):  
Random Sampling ◽  
Geographical Information Systems ◽  
Field Measurements ◽  
Decision Support Tool ◽  
Accurate Estimate ◽  
Ease Of Use ◽  
Geographical Information ◽  
Support Tool ◽  
Topographic Complexity ◽  
Hill Country

To develop a protocol to guide pasture sampling for estimation of paddock pasture mass in hill country, a range of pasture sampling strategies, including random sampling, transects and stratification based on slope and aspect, were evaluated using simulations in a Geographical Information Systems computer environment. The accuracy and efficiency of each strategy was tested by sampling data obtained from intensive field measurements across several farms, regions and seasons. The number of measurements required to obtain an accurate estimate was related to the overall pasture mass and the topographic complexity of a paddock, with more variable paddocks requiring more samples. Random sampling from average slopes provided the best balance between simplicity and reliability. A draft protocol was developed from the simulations, in the form of a decision support tool, where visual determination of the topographic complexity of the paddock, along with the required accuracy, were used to guide the number of measurements recommended. The protocol was field tested and evaluated by groups of users for efficacy and ease of use. This sampling protocol will offer farmers, consultants and researchers an efficient, reliable and simple way to determine pasture mass in New Zealand hill country settings. Keywords: hill country, feed budgeting, protocol pasture mass, slope

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