The Relationship in Field Experiments Between Population Density of Globodera Rostochiensis Before Planting Potatoes and Yield of Potato Tubers

Nematologica ◽  
1982 ◽  
Vol 28 (3) ◽  
pp. 277-284 ◽  
Author(s):  
J.W. Seinhorst
Keyword(s):  
Population Density ◽  
Field Experiments ◽  
Globodera Rostochiensis ◽  
Potato Tubers ◽  
The Relationship

Effect of phosphorus on the specific gravity of potato tubers (Solanum tuberosum L.) of cultivars Kennebec and Coliban

1989 ◽  
Vol 29 (6) ◽  
pp. 869 ◽  
Author(s):  
NA Maier ◽  
KA Potocky-Pacay ◽  
AP Dahlenburg ◽  
CMJ Williams
Keyword(s):  
Specific Gravity ◽  
Field Experiments ◽  
Solanum Tuberosum L ◽  
Phosphorus Concentration ◽  
Potato Tubers ◽  
Significant Relationships ◽  
Linear Relationships ◽  
Phosphorus Application ◽  
The Relationship ◽  
Tissue Phosphorus

The effect of phosphorus banded at planting, at rates up to 240 kg/ha, on the specific gravity of tubers of cvv. Kennebec (10 sites) and Coliban (5 sites) was investigated using field experiments conducted during 1984-85, 1985-86 and 1986-87. The relationship between specific gravity and phosphorus concentration in petioles of youngest fully expanded leaves (P-YFEL) was also determined. As the rate of applied phosphorus increased there were significant positive and negative trends in specific gravity. However, the size of the effect varied between sites; for example, the maximum and minimum ranges in specific gravity (based on treatment means) due to phosphorus application were 1.0762-1.0869 (site 13) and 1.0753-1.0772 (site 24), respectively for the cv. Kennebec and 1.0598-1.0683 (site 22) and 1.0715-1.0753 (site 17), respectively for the cv. Coliban. Rates of applied phosphorus, which resulted in maximum specific gravity, also varied between sites. Maximum specific gravities occurred at phosphorus rates in the ranges 0-100 and 40-240 kg/ha for cvv. Kennebec and Coliban, respectively. There were significant relationships (5 quadratic and 1 negative linear) between phosphorus concentration in P-YFEL and specific gravity for cv. Kennebec at all 6 responsive sites. Phosphorus concentrations in P-YFEL associated with maximum specific gravities were in the range 0.29-0.51%. For cv. Coliban, over similar tissue phosphorus concentration ranges, there were significant (P<0.05) positive linear relationships for 1 responsive and 2 non-responsive sites. When data for cv. Kennebec were pooled for all sites, there was a significant (P<0.05) quadratic relationship between specific gravity and tissue phosphorus concentration (range 0.22-0.77%). For the cv. Coliban the trend was not significant (P>0.05). We have concluded that the rate of phosphorus banded at planting can affect specific gravity and that the cvv. Kennebec and Coliban differ in their sensitivity to this effect.

Simulation on Extrusion Comminution Model of Roller Press

2010 ◽  
Vol 156-157 ◽  
pp. 1702-1707
Author(s):  
Xiang Wen Cheng ◽  
Jinchao Liu ◽  
Qi Zhi Ding ◽  
Li Ming Song ◽  
Zhan Lin Wang
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Field Experiments ◽  
Size Ratio ◽  
Optimum Operating ◽  
Extrusion Force ◽  
Particle Size Ratio ◽  
Small Constant ◽  
Working Parameters ◽  
The Relationship

How to predict the relationship among particle size and among product size, to establish the relationship between the granularity and working parameters in the process of grinding and to determine the optimum operating parameters. With proposing BS squeeze crush model by L. Bass and the idea of roll surface division as the material uneven extrusion force are adopted. Based on field experiments the experimental data is analyzed, the select function and the breakage functions are fitted with MATLAB software, and obtaining their model. The comminution model is determined by the roller division. We obtain the model parameter through the experimental data. Through model analysis shows: the relationship between particle breakage and energy absorption, namely the smaller size of the same power, the lower broken; the breakage diminishes with the decrease of particle size ratio and it will be tending to a small constant when the smaller particle size ratio. The breakage functions rapidly decrease within ratio of between 0.2-0.7. This shows: the energy consumption will rapidly increase when the particle size of less than 0.2 in broken; the selection diminish with the decrease of particle size. Pressure (8-9MPa) should be the most appropriate value.

Effects of irrigation regimes on powdery scab disease and yield of potatoes

1986 ◽  
Vol 26 (6) ◽  
pp. 745 ◽  
Author(s):  
PA Taylor ◽  
SP Flett ◽  
RFde Boer ◽  
D Marshall
Keyword(s):  
Large Scale ◽  
Field Experiments ◽  
Field Trials ◽  
Powdery Scab ◽  
Infested Soil ◽  
Spongospora Subterranea ◽  
Potato Tubers ◽  
Potato Plants ◽  
Tuber Set ◽  
Large Scale Field

The period of susceptibility of potato tubers to powdery scab (Spongospora subterranea) was studied by inoculating potato plants with spores, or by watering plants in infested soil, at different stages of plant development in greenhouse conditions. Maximum susceptibility began about 1 week before the stage when 50% of stolons had swollen to at least 5-mm diameter (tuber set), and ended 3-4 weeks later. With holding irrigation water during this period reduced the severity of powdery scab by 65-75% in field experiments in 1981-82 and 1982-83, but had no apparent effect on disease severity in 3 out of 6 large-scale field trials during 1984-85.

Effect of nitrogen, phosphorus and potassium application on yield of potato tubers (Solatium tuberosum L.)

1987 ◽  
Vol 108 (2) ◽  
pp. 321-329 ◽  
Author(s):  
U. C. Sharma ◽  
B. R. Arora
Keyword(s):  
Field Experiments ◽  
Sandy Loam ◽  
Farmyard Manure ◽  
Potato Tubers ◽  
Solatium Tuberosum ◽  
Loam Soil ◽  
Potassium Application ◽  
Phosphorus And Potassium ◽  
Grade Increase ◽  
Nitrogen Phosphorus

SummarySix field experiments, three each during 1982–3 and 1983–4, were conducted on a sandy loam soil to study the effect of varying levels of nitrogen, phosphorus and potassium, in the absence and presence of farmyard manure (FYM) (30 t/ha), on the number of tubers and yield of potato in three grades. Increase in nitrogen, phosphorus and potassium application, in the absence or presence of FYM, did not significantly affect the total number of tubers/m2 but did affect the number of tubers in different grades. An increase in nitrogen and potassium significantly decreased the number of tubers/m2 in small (< 25 g) and increased in medium (25–75 g) and large (> 75 g) grades at 45, 60, 75 and 90 days after planting. Increase in the application of phosphorus increased the number of tubers/m2 in the small grade and decreased it in the large grade but did not affect the number in the medium grade. Increase in nitrogen and potassium application decreased the tuber yield in the small grade and increased it in the medium and large grades. Applied phosphorus increased the yield in the small and medium grades and decreased it in the large grade. The increase in the yield of tubers with increase in nitrogen and potassium application was found to be caused by an increase in the number of tubers in the medium and large grades at the expense of the small grade; however, with applied phosphorus the increase in yield was due to increase in the weight of individual tubers within the small and medium grades. FYM application decreased the number of tubers in the small grade and increased it in the medium and large grades. The response of potato to nitrogen increased and to phosphorus and potassium decreased with the application of FYM.

scholarly journals Interactions Between Chill-Hours and Degree-Days Affect Carpogenic Germination in Monilinia vaccinii-corymbosi

2001 ◽  
Vol 91 (1) ◽  
pp. 77-83 ◽  
Author(s):  
H. Scherm ◽  
A. T. Savelle ◽  
P. L. Pusey
Keyword(s):  
Laboratory Experiments ◽  
Field Experiments ◽  
Degree Days ◽  
Carpogenic Germination ◽  
Conditioning Period ◽  
Low Degree ◽  
Heating Degree Days ◽  
Relationship Of ◽  
High Degree ◽  
The Relationship

The relationship of cumulative chill-hours (hours with a mean temperature <7.2°C) and heating degree-days (base 7.2°C) to carpogenic germination of pseudosclerotia of Monilinia vaccinii-corymbosi, which causes mummy berry disease of blueberry, was investigated. In two laboratory experiments, pseudosclerotia collected from rabbiteye blueberry in Georgia were conditioned at 5 to 6°C for 26 to 1,378 h prior to placement in conditions favorable for germination and apothecium development. The number of chill-hours accumulated during the conditioning period affected the subsequent proportion of pseudosclerotia that germinated and produced apothecia, with the greatest incidence of carpogenic germination occurring after intermediate levels of chilling (≈700 chill-hours). The minimum chilling requirement for germination and apothecium production was considerably lower than that reported previously for pseudo-sclerotia from highbush blueberry in northern production regions. The rate of carpogenic germination was strongly affected by interactions between the accumulation of chill-hours and degree-days during the conditioning and germination periods; pseudosclerotia exposed to prolonged chilling periods, once transferred to suitable conditions, germinated and produced apothecia more rapidly (after fewer degree-days had accumulated) than those exposed to shorter chilling periods. Thus, pseudosclerotia of M. vaccinii-corymbosi are adapted to germinate carpogenically following cold winters (high chill-hours, low degree-days) as well as warm winters (low chill-hours, high degree-days). Results were validated in a combined field-laboratory experiment in which pseudosclerotia that had received various levels of natural chilling were allowed to germinate in controlled conditions in the laboratory, and in two field experiments in which pseudosclerotia were exposed to natural chilling and germination conditions. A simple model describing the timing of apothecium emergence in relation to cumulative chill-hours and degree-days was developed based on the experiments. The model should be useful for better timing of field scouting programs for apothecia to aid in management of primary infection by M. vaccinii-corymbosi.

Letters to the Editor

PEDIATRICS ◽  
1963 ◽  
Vol 31 (6) ◽  
pp. 1058-1059
Author(s):  
WILLIAM A. SILVERMAN
Keyword(s):  
Population Density ◽  
Nosocomial Infections ◽  
Specific Recommendation ◽  
Letters To The Editor ◽  
Airborne Infection ◽  
The Relationship

I was saddened to read that Doctor Harvie thinks the Committee on Fetus and Newborn has contributed to creeping authoritarianism by making a specific recommendation after evaluating evidence concerning the relationship between "spacing out" and airborne infection in hospital nurseries. Moreover I think he has misinterpreted the Committee's recommendations if he believes that they have advised nurseries to place sole reliance on reducing population density in order to minimize the risk of nosocomial infections. As Doctor Harvie comments, different modes of spread may be involved in the various types of infection that can be acquired in a newborn nursery.

Influence of fruit age of the Brazilian Green Dwarf coconut on the relationship between Aceria guerreronis population density and percentage of fruit damage

2017 ◽  
Vol 72 (4) ◽  
pp. 329-337 ◽  
Author(s):  
André Silva Guimarães Sousa ◽  
Poliane Sá Argolo ◽  
Manoel Guedes Correa Gondim ◽  
Gilberto José de Moraes ◽  
Anibal Ramadan Oliveira
Keyword(s):  
Population Density ◽  
Aceria Guerreronis ◽  
Fruit Damage ◽  
The Relationship

scholarly journals Nitrogen management in wheat based on the normalized difference vegetation index (NDVI)

2018 ◽  
Vol 48 (9) ◽  
Author(s):  
André Luis Vian ◽  
Christian Bredemeier ◽  
Marcos Alexandre Turra ◽  
Cecília Paz da Silva Giordano ◽  
Elizandro Fochesatto ◽  
...  
Keyword(s):  
Technical Efficiency ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Field Experiments ◽  
Shoot Biomass ◽  
Sensor Field ◽  
N Dose ◽  
Plant Emergence ◽  
The Moment ◽  
The Relationship

ABSTRACT: Biomass production and nitrogen (N) accumulated in wheat shoots may be used for quantifying optimal topdressing nitrogen doses. The objective of this study was to develop and validate models for estimating the amount of biomass and nitrogen accumulated in shoots and the N topdressing dose of maximum technical efficiency in wheat using the normalized difference vegetation index (NDVI) measured by an active optical canopy sensor. Field experiments were carried out in two years and treatments consisted of N doses applied at plant emergence and as topdressing. NDVI, shoot biomass and N accumulated in shoots at the growth stage of six fully expanded leaves and grain yield were evaluated, being determined the topdressing N dose of maximum technical efficiency (DMTE). The NDVI was positively correlated to shoot biomass and N content in shoots and models for the relationship between these variables were developed and validated. The DMTE was negatively correlated with the NDVI value evaluated at the moment of N topdressing application. Thus, NDVI evaluation by an active optical canopy sensor can be used for nitrogen fertilization in variable rate, allowing the adjustment of applied N doses in different areas within a field.

scholarly journals Reproduction and population structure of the sea cucumber Holothuria tubulosa in the Dardanelles Strait, Turkey

2015 ◽  
Vol 17 (1) ◽  
pp. 47 ◽  
Author(s):  
H. DERELİ ◽  
S. TÜRK ÇULHA ◽  
M. ÇULHA ◽  
B. H. ÖZALP ◽  
A. A. TEKİNAY
Keyword(s):  
Population Density ◽  
Gonadosomatic Index ◽  
Morphological Characteristics ◽  
Environmental Parameters ◽  
Population Characteristics ◽  
High Positive Correlation ◽  
Mediterranean Populations ◽  
Reproductive Patterns ◽  
First Time ◽  
The Relationship

In this study, Holothuria tubulosa Gmelin 1791 was investigated from April 2013 to March 2014 in the Dardanelles Strait, to outline the morphological characteristics, reproductive patterns and the relationship between population characteristics and environmental parameters. Between 15 and 30 individuals of this species were sampled monthly from three stations. There was a negative allometry between length and weight, being gutted weight the most reliable measurement for this species. Reproductive patterns of the species were identified the first time for Turkish coasts. By macroscopic examination of the gonads, smallest sizes (gutted length) were measured as 8.4 and 8.1 cm for female and male, respectively. Sex ratio was calculated as 1: 1.1 with differences between seasons. The reproduction of sea cucumbers occurred between August and September after Gonadosomatic Index (GSI) values reached their maximum in July. The species was found down to 10 m depth with a population density of 0.21 / m2, which was rather low compared to previously reported values for Mediterranean populations of this species. There was a high positive correlation between population density and GSI of the species. The highest population density was observed where the largest sea grass meadows are found.

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