Consistency of long-term marketable yield of carrot and onion cultivars in muck (organic) soil in relation to seasonal weather

2010 ◽  
Vol 90 (5) ◽  
pp. 755-765 ◽  
Author(s):  
M. T. Tesfaendrias ◽  
M. R. McDonald ◽  
J. Warland
Keyword(s):  
Allium Cepa ◽  
Daucus Carota ◽  
Organic Soil ◽  
Data Sets ◽  
Fresh Market ◽  
Marketable Yield ◽  
Daucus Carota L ◽  
Weather Patterns ◽  
The Mean

To identify carrot and onion cultivars that provide consistent marketable yields, we tracked the yields of five fresh market carrot [(Daucus carota L. subsp. sativus (Hoffm.) Arcang.] and six onion (Allium cepa L.) cultivars for at least 13 yr. Relationships between long-term weather variables and marketable yields were also investigated. The effects of cultivar, year and cultivar × year interactions on yield of carrots and onions were assessed. Cultivar and year had significant effects on carrot and onion yields, while the interaction was significant in only one of four data sets of carrot yield. Carrot cv. Cellobunch (95.4 t ha–1) and onion cv. Corona (74.1 t ha–1) had the highest mean marketable yields over the years studied. There was a slight positive correlation between mean yield of the assessed carrots and maximum temperatures in September (r = 0.44). Mean carrot yield was also somewhat negatively correlated with total rainfall in July (r = –0.43) and with number of days with rain in August (r = –0.43) and September (r = –0.44). Most onion cultivars showed stronger relationships between marketable yield and various weather patterns. Marketable yield of onions increased with an increase in the number of days with rainfall in June (r = 0.57). The mean marketable yield of the six onion cultivars decreased in relation to temperatures ≥30°C in June (r = –0.55) and August (r = –0.53). The mean yield of all the onions in the trials was negatively correlated (r = –0.78) with growing degree days (base 5°C, May to August). The results indicated that the data from long-term cultivar trials can be used to identify cultivars that yield well despite seasonal variations in weather. Key words: Daucus carota, Allium cepa, temperature, rainfall

scholarly journals Internal consistency of the Regional Brewer Calibration Centre for Europe triad during the period 2005–2016

2018 ◽  
Vol 11 (7) ◽  
pp. 4059-4072 ◽  
Author(s):  
Sergio Fabián León-Luis ◽  
Alberto Redondas ◽  
Virgilio Carreño ◽  
Javier López-Solano ◽  
Alberto Berjón ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Data Sets ◽  
Individual Values ◽  
Relative Standard ◽  
The World ◽  
The Mean ◽  
The Individual ◽  
Ozone Column

Abstract. Total ozone column measurements can be made using Brewer spectrophotometers, which are calibrated periodically in intercomparison campaigns with respect to a reference instrument. In 2003, the Regional Brewer Calibration Centre for Europe (RBCC-E) was established at the Izaña Atmospheric Research Center (Canary Islands, Spain), and since 2011 the RBCC-E has transferred its calibration based on the Langley method using travelling standard(s) that are wholly and independently calibrated at Izaña. This work is focused on reporting the consistency of the measurements of the RBCC-E triad (Brewer instruments #157, #183 and #185) made at the Izaña Atmospheric Observatory during the period 2005–2016. In order to study the long-term precision of the RBCC-E triad, it must be taken into account that each Brewer takes a large number of measurements every day and, hence, it becomes necessary to calculate a representative value of all of them. This value was calculated from two different methods previously used to study the long-term behaviour of the world reference triad (Toronto triad) and Arosa triad. Applying their procedures to the data from the RBCC-E triad allows the comparison of the three instruments. In daily averages, applying the procedure used for the world reference triad, the RBCC-E triad presents a relative standard deviation equal to σ = 0.41 %, which is calculated as the mean of the individual values for each Brewer (σ157 = 0.362 %, σ183 = 0.453 % and σ185 = 0.428 %). Alternatively, using the procedure used to analyse the Arosa triad, the RBCC-E presents a relative standard deviation of about σ = 0.5 %. In monthly averages, the method used for the data from the world reference triad gives a relative standard deviation mean equal to σ = 0.3 % (σ157 = 0.33 %, σ183 = 0.34 % and σ185 = 0.23 %). However, the procedure of the Arosa triad gives monthly values of σ = 0.5 %. In this work, two ozone data sets are analysed: the first includes all the ozone measurements available, while the second only includes the simultaneous measurements of all three instruments. Furthermore, this paper also describes the Langley method used to determine the extraterrestrial constant (ETC) for the RBCC-E triad, the necessary first step toward accurate ozone calculation. Finally, the short-term or intraday consistency is also studied to identify the effect of the solar zenith angle on the precision of the RBCC-E triad.

scholarly journals Outliers in Mixed Models for Monthly Average Temperatures

2016 ◽  
Vol 39 (3) ◽  
Author(s):  
Mercedes Andrade-Bejarano ◽  
Nicholas T. Longford
Keyword(s):  
Mixed Models ◽  
Data Sets ◽  
Weather Patterns ◽  
Monthly Average ◽  
Recording Process ◽  
Simulation Based ◽  
Site Variation ◽  
Valle Del Cauca ◽  
The Impact

Long-term series of monthly average temperatures taken at 28 sites in Valle del Cauca, Colombia, are studied. Mixed models are applied to cater for the within- and between-site variation. Outliers are inevitable in such studies, due to faulty equipment, slip-ups in the recording process, or unusual weather patterns. We apply a simulation-based approach to the assessment of the outlier status of suspected observations. It is a method based on graphical comparisons of user-defined features, related to large residuals, in the real andsimulated data sets. Robustness in the identification of the outliers is achieved by applying the procedure with several alternative models. The impact of the identified outliers is assessed. Two meteorological stations, Zaragoza and Monteloro, are identified as having many outliers, so that all the data from them should be discarded.

scholarly journals 214 Yield and Quality Response of Carrot (Daucus carota L.) to Simulated Storm Damage

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 479A-479
Author(s):  
Michael E. Bartolo ◽  
Frank C. Schweissing
Keyword(s):  
Daucus Carota ◽  
Yield Components ◽  
Total Yield ◽  
Growing Season ◽  
Storm Damage ◽  
Lower Yield ◽  
Marketable Yield ◽  
Daucus Carota L ◽  
Yield And Quality ◽  
Quality Response

Parts of Colorado receive more hail than almost any other area in the nation. Severe storms can injure crop tissue and, thus, lower yield and predispose the crop to disease infection. Our study was conducted to determine the yield and quality response of carrot (Daucus carota L.) to simulated storm damage during different periods of plant development. We removed 33% and 67% of the carrot foliage at four dates, spaced 10 days apart, during the middle of the growing season. In 1997 and 1998, 67% defoliation significantly reduced total and marketable yields more than did 33% defoliation. Total yield components, length and diameter, were similarly affected. Defoliation, in general, decreased yield the greatest when it when it occurred at the later stages of development. Carrot foliage continued to develop and grow after all defoliation events. Nonetheless, moderate (33%) and severe (67%) foliage loss reduced marketable yield and yield components of carrots.

Zone tillage systems for onion and carrot production on muck soils

2004 ◽  
Vol 84 (4) ◽  
pp. 1167-1169 ◽  
Author(s):  
C. J. Swanton ◽  
S. Janse ◽  
K. Chandler ◽  
B. D. Booth
Keyword(s):  
Key Words ◽  
Allium Cepa ◽  
Daucus Carota ◽  
Conventional Tillage ◽  
Viable Alternative ◽  
Reduced Tillage ◽  
Tillage Systems ◽  
Daucus Carota L ◽  
Allium Cepa L

This study examined whether zone tillage was a viable alternative to conventional tillage for carrot [Daucus carota L. var. sativus (Hoffm.) Arcang.] and onion (Allium cepa L.) production on muck soils. Total and marketable yields under zone tillage were e qual to (carrot) or greater than (onion) yields under conventional tillage. Carrot yields did not differ between raised and flat bed treatments. Key words: Reduced tillage, conventional tillage, Daucus carota L. var. sativus (Hoffm.) Arcang.); Allium cepa L.

Consistency of Towing Speed and Sampling Depth for the Continuous Plankton Recorder

1993 ◽  
Vol 73 (4) ◽  
pp. 967-970 ◽  
Author(s):  
G. C. Hays ◽  
A. J. Warner
Keyword(s):  
Time Series ◽  
North Atlantic ◽  
Data Sets ◽  
Sampling Depth ◽  
The North ◽  
The North Sea ◽  
The Mean ◽  
Towing Speed ◽  
Term Data

The mean annual towing speed of the Continuous Plankton Recorder (CPR) varied systematically between 1946 and 1991. By mounting a pressure transducer on the CPR to record towing depth, it was shown, however, that changes in towing speed did not cause a significant change in towing depth, although the mean towing depth (6–7 m, SD=l-7 m, N=77) was shallower than the previously assumed towing depth of 10 m. Thus the observed changes in towing speed are unlikely to have caused discontinuities in the CPR time-series by affecting sampling depth.Long-term data sets play an important role in attempts to understand the causes of fluctua- tions in plankton abundance. The Continuous Plankton Recorder (CPR) survey provides multi- decadal information on plankton abundance in the North Sea and North Atlantic (McGowan, 1990), and is one of the longest standing marine plankton abundance time-series. However, while the CPR time-series has great potential, as with all other data sets spanning many years, questions may be asked regarding the consistency with which the data have been collected and hence the true continuity of the time-series.

Limitations to carrot (Daucus carota L.) productivity when grown with reduced rates of frequent irrigation on a free-draining, sandy soil

2003 ◽  
Vol 54 (5) ◽  
pp. 499 ◽  
Author(s):  
Mark R. Gibberd ◽  
Allan G. McKay ◽  
Tim C. Calder ◽  
Neil C. Turner
Keyword(s):  
Soil Water ◽  
Sandy Soil ◽  
Daucus Carota ◽  
Water Availability ◽  
Leaf Growth ◽  
Leaf Biomass ◽  
Marketable Yield ◽  
Daucus Carota L ◽  
Soil Water Tension ◽  
Irrigation Treatments

To determine the influence of reduced irrigation input, carrot (Daucus carota L. cv. Ivor) plants were grown on a coarse-textured, sandy soil during summer near Perth, Western Australia. Irrigation was applied daily with sprinklers at 5 rates ranging from 47 to 151% replacement of daily pan evaporation (Ep). A reduction in irrigation from the industry standard of 151% Ep to 124 or 97% Ep resulted in a 17% increase in water use efficiency (WUE) when calculated as total root yield/water applied. However, the percentage of total roots that were marketable declined with reduction in irrigation, being 73, 56, and 63% at 151, 124, and 97% Ep, respectively. This minimised any increase in WUE when calculated on a marketable yield basis. Further reductions in irrigation to 47 and 73% Ep resulted in large reductions in yield, WUE, and the percentage of marketable roots. Leaf biomass was not significantly different between the 151 and 124% Ep treatments and was reduced by 55 and 85% at 73 and 47% Ep, respectively. Soil water tension (ψs) varied from 4 to 80 kPa among the irrigation treatments. Pre-dawn leaf water potential (ψl) was most sensitive to ψs over a ψs range of 0–20 kPa and the influence of ψs on ψl was small (400 kPa) compared with the diurnal variations in ψl of up to 1400 kPa, which occurred independently of significant changes in bulk soil ψs. There was no significant effect of irrigation on the osmotic potential of leaf sap and there was no evidence of osmotic adjustment. For all irrigation treatments, photosynthesis (Pn) peaked in the early morning (0830 hours) at rates of 17–20 μmol CO2/m2.s, after which Pn decreased to a transient minimum value at midday. The diurnal decline in Pn was positively correlated with ψl for all treatments, and minimum values of Pn varied from 12.5 to 7.8 μmol CO2/m2.s for plants grown with 151 and 47% of Ep, respectively. When grown under frequently applied, suboptimal irrigation, carrot productivity is predominately limited by a reduction in leaf growth rates that limits leaf area and matches transpiration requirements with water availability. Furthermore, even under conditions of water deficit, the aerial environment imposes a greater constraint to Pn than soil water availability.

scholarly journals Changes in Vitamin C Content and Soluble Solids of Carrot Content (Daucus Carota L.) During Storage / Zmeny v Obsahu Vitamínu C a Rozpustnej Sušiny Mrkvy (Daucus Carota L.) Počas Skladovania

2013 ◽  
Vol 16 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Magdaléna Valšíková ◽  
Miroslav Šlosár ◽  
Rudolf Ryban ◽  
Sami Shehata ◽  
Alžbeta Hegedűsová
Keyword(s):  
Vitamin C ◽  
Daucus Carota ◽  
Matter Content ◽  
Soluble Solids ◽  
Dry Matter Content ◽  
Soluble Solids Content ◽  
Daucus Carota L ◽  
Laboratory Conditions ◽  
Solids Content

Abstract The average vitamin C content of fresh carrots was 56 mg.kg-1. Amount of vitamin C was reduced by the length of storage and storage environment. On average, the most significant decrease in vitamin C to 24.4 mg.kg-1 under laboratory conditions was reported after 56 days when stored carrots were packed in plastic box. When stored in a refrigerator, the vitamin C content decreased to 24.7 mg.kg-1 after 126 days of storage in a plastic box. During both experimental periods in laboratory conditions, the most vitamin C was preserved while being wrapped plastic wrap. This way of packaging also enabled relatively long-term preservation of freshness in variety called “Komarno”, which was up to 60 days. The second best option in this respect is the packed carrot in microtene bags. The least convenient was to store the carrots open without packaging. In the case of refrigerated storage, the options of packaging in plastic wrap and microtene bags were also the best. The most significant decline in vitamin C was found in the variant without packaging and in the food box. Average soluble solids (refractometry dry matter) content in fresh roots reached 7.6%. During storage under laboratory conditions, the SS values increased to 14.8% after 14 days when the carrot was stored open without packaging. In the refrigerator, the soluble solids content in carrots increased to 12.7% after 28 days of storage without packaging. Increase in soluble solids content was mainly caused by transpiration process. Under laboratory conditions, evaporation and increase of soluble solids were faster compared to the variants stored in the cooler

NONFUMIGANT NEMATICIDES FOR CONTROL OF NORTHERN ROOT-KNOT NEMATODE IN MUCK-GROWN CARROTS

1984 ◽  
Vol 64 (1) ◽  
pp. 175-179 ◽  
Author(s):  
G. BELAIR
Keyword(s):  
Daucus Carota ◽  
Field Experiments ◽  
Control Method ◽  
Organic Soil ◽  
Meloidogyne Hapla ◽  
Nematode Control ◽  
Root Knot Nematode ◽  
Daucus Carota L ◽  
Application Method

Field experiments were conducted to determine the effects of rate and application method on the effectiveness of nonfumigant nematicides to protect carrot roots (Daucus carota L.) against Meloidogyne hapla, Chitwood, in organic soil. Carbamate compounds, aldicarb and oxamyl, provided better protection to carrot roots than organophosphorus, phenamiphos and terbufos compounds. In-furrow application of granular nematicides at the rate of 1.5 kg a.i./ha was more effective than band and broadcast incorporation at a rate of 6 kg a.i./ha. The standard control method with the fumigant, 1,3-dichloropropene, offered the best nematode control and the highest marketable yields.Key words: Daucus carota, Meloidogyne hapla

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