scholarly journals WATERMELON SEEDLING MORTALITY ASSOCIATED WITH Pythium aphanidermatum

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 873a-873 ◽  
Author(s):  
Warren Roberts ◽  
Benny Bruton ◽  
Jonathan Edelson ◽  
Wenhua Lu ◽  
Penny Perkins-Veazie ◽  
...  

Forty-one cultivars of triploid and diploid watermelons (Citrullus lanatus) were grown at Lane, Oklahoma in 2003. Seeds were placed in Jiffy-9 pellets in a greenhouse on 21 May. Fields were prepared with raised beds 1 m wide covered with black plastic. Plots were 3 m wide by 15 m long, with 4 replications, arranged as a randomized complete block. Seedlings were transplanted to the field on 4 June. From 4–9 June, rainfall occurred 5 days. Maximum soil temperatures at 5 cm, under bare soil, from 1–9 June were 34, 34, 35, 26, 22, 26, 31, 29, and 32 °C, respectively. On 9 June, 84% of the seedlings were dead. Lesions were observed on the roots and stems and isolations were made from symptomatic tissues. The predominant pathogen isolated from the seedlings was Pythium aphanidermatum. Some of the cultivars appear to have some degree of resistance to P. aphanidermatum. Mortality among the cultivars, averaged across all replications, ranged from 33% to 100%. The cultivars with the lowest mortality were “Tri-X Carousel” (33%), `Sunny' (40%), `WT-02-31' (53%), `Ole' (58%), and `Tri-X Palomar' (68%). New seeds were seeded in the greenhouse on 16 June, and transplanted to the field on June 30. The replacement seedlings were planted in the same field, in the same location as the previous plants. Maximum soil temperatures for the two week interval following the second planting ranged from 33 to 39 °C, with only one rain of 0.8 cm occurring 10 days after planting. There was no apparent plant loss due to P. aphidermatum in the second planting.

2014 ◽  
Vol 24 (5) ◽  
pp. 535-545 ◽  
Author(s):  
Caitlin E. Splawski ◽  
Emilie E. Regnier ◽  
S. Kent Harrison ◽  
Karen Goodell ◽  
Mark A. Bennett ◽  
...  

Zucchini squash (Cucurbita pepo) has a high pollination demand, and the native, ground-nesting squash bee (Peponapis pruinosa) provides the majority of the crop’s pollination requirement in some environments. Squash bees nest directly in crop fields, and nests can be disturbed by tillage and other management operations. Mulches that use municipal waste materials may provide a weed control strategy for squash plantings that is more benign to squash bees than cultivation. Field and greenhouse studies were conducted in 2011 and 2012 to compare the effects of nontillage weed control methods including polyethylene black plastic, woodchips, shredded newspaper, a combination of shredded newspaper plus grass clippings (NP + grass), and bare soil (control) on soil characteristics, squash pollination and fruit production, and squash bee nesting. Woodchips, shredded newspaper, and NP + grass mulch decreased soil temperature, while soils beneath newspaper mulch retained more moisture. Unmarketable, misshapen fruit occurred more frequently in plastic than in the other mulch treatments. No measurable differences in floral resource production or crop pollination were found among treatments, suggesting that misshapen fruit resulted from high soil temperatures in black plastic plots rather than poor pollinator attraction. Squash bee nests were located within bare soil, newspaper, and NP + grass plots, indicating that these mulches did not prevent nesting. NP + grass mulch had a positive effect on plant growth and fruit production, possibly from an addition of plant-available nitrogen or the presence of preferable nesting ground. Shredded newspaper when combined with grass clippings performed as an effective mulch material that improved crop performance with no apparent negative impacts on squash bee nesting or on squash floral resources and pollination.


HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 596B-596
Author(s):  
David G. Himelrick

The effect of seven types of plastic mulches on total, early, and late season yield was evaluated for three years in the annual hill strawberry production system. Black plastic mulches differed only from the significantly reduced yields found on unmulched bare ground treatments. Although not significantly different in any year, the top performing mulch treatments varied with production year and cultivar. In the wet and warm harvest season of 1991, the highest yielding treatments were IRT-76, clear, and ALOR-brown. In the dry and cool 1992 season, the top performers were white on black, black, and ALOR-brown. For the cool and moderately wet 1993 season, the best performance was recorded on black, white on black, and clear. Average soil temperatures from warmest to coolest were found with black, black on white, clear, IRT-76, ALOR-brown, red, silver, white on black, and bare soil treatments.


2010 ◽  
Vol 20 (1) ◽  
pp. 224-233 ◽  
Author(s):  
Garry G. Gordon ◽  
Wheeler G. Foshee ◽  
Stewart T. Reed ◽  
James E. Brown ◽  
Edgar L. Vinson

Okra (Abelmoschus esculentus ‘Clemson Spineless’) was grown on an Orangeburg sandy loam soil in Shorter, AL. Okra was direct-seeded in single rows. Treatments consisted of five mulch colors: black, white, red, silver, and blue installed either with or without spun-bonded row cover. Soil temperatures were 4 to 7 °C lower than air temperatures in all treatments. The use of darker (black, blue, red) -colored plastic mulches increased early and total yield of okra compared with bare soil with and without row cover. Increased soil and air temperatures did not always correlate to an increase in yield. It can be concluded that the use of dark plastic mulch is advantageous to growers of okra in climates that do not have cool springs, but the added use of row covers to plastic mulch has no effect on growth and yield. The profit of marketable okra produced using a row cover was $1.37 versus $1.35 per pound without a cover in 2003 and $1.28 versus $1.29 per pound in 2004. Blue plastic mulch is ≈$0.08 per foot more expensive than black plastic. Our data do not show an economic advantage for blue over black mulch for okra, but the positive effect cited by other authors may be more pronounced with leafy vegetables.


HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 681e-681
Author(s):  
B.W. Roberts ◽  
Jeff Anderson

Bell pepper (Capsicum annuum L.) was grown in 1989, 1990, and 1991. Cultural modifications were used in an effort to alleviate heat stress, improve fruit set, reduce sunscald, and improve yield quantity and quality. Treatments included bare soil, plastic mulch (both black and white), straw mulch, living rye (Secale cereale) mulch, and row covers (white and black) suspended above the foliage. Soil temperature at 2.5, 10, and 20 cm, soil moisture at 20 cm, and yield parameters were recorded. In general, plots containing white rowcovers produced good yields each year, straw mulched plots produced good yields two out of three years, plots with black plastic mulch gave poor yields two out of three years, and plots with living rye gave consistently poor yields. Yield inconsistency from year to year was correlated with, and can be explained by, soil temperatures. Sunscald was reduced by rowcovers.


HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 251c-251
Author(s):  
Fahrurrozi Aziz ◽  
Katrine A. Stewart

The types of plastic mulch used in horticultural production often fulfill only a few of the grower's needs. Black plastic mulch controls weeds, but can burn young plants. Clear mulch, while warming the soil and enhancing early crop growth, allows prolific weed growth and development. Accordingly, an experiment using a randomized complete-block design with-four replications was set up to compare the effects of black, microperforated black, silver, and wavelength-selective (IRT-76) green mulches, and bare soil on weed growth and development, and on soil temperature and moisture. Each mulch was evaluated for its optical properties. All mulches significantly reduced final stands of seeded weeds compared with bare soil. IRT-76 green had the warmest mean soil temperatures, followed by silver, black, and microperforated black mulches, and bare soil. Soil moisture content was generally higher under plastic mulches than bare soil.


2015 ◽  
Vol 12 (1) ◽  
pp. 23-30 ◽  
Author(s):  
C. Bertrand ◽  
L. González Sotelino ◽  
M. Journée

Abstract. Soil temperatures at various depths are unique parameters useful to describe both the surface energy processes and regional environmental and climate conditions. To provide soil temperature observation in different regions across Belgium for agricultural management as well as for climate research, soil temperatures are recorded in 13 of the 20 automated weather stations operated by the Royal Meteorological Institute (RMI) of Belgium. At each station, soil temperature can be measured at up to 5 different depths (from 5 to 100 cm) in addition to the bare soil and grass temperature records. Although many methods have been developed to identify erroneous air temperatures, little attention has been paid to quality control of soil temperature data. This contribution describes the newly developed semi-automatic quality control of 10-min soil temperatures data at RMI.


2015 ◽  
Vol 33 (2) ◽  
pp. 261-266 ◽  
Author(s):  
Márcia M Echer ◽  
Graciela M Dalastra ◽  
Tiago L Hachmann ◽  
Elcio S Klosowski ◽  
Vandeir F Guimarães

An important aspect in the cultivation of vegetables is the quality of the product to be marketed, free from dirt and damage and the practice of mulching could be an option, but there is scarse information. The aim of this study was to evaluate the influence of mulching on the production traits of three cultivars of Pak Choi. The experiment was set up during March to May 2013 using a split plot randomized block design, with four replications. Soil cover treatments (white agrotextile, black agrotextile, black plastic, silver plastic, tifton straw and bare soil) were arranged in the plots, and three cultivars of Pak Choi (Green Pak Choi, White Pak Choi and Chingensai Natsu Shomi) in subplots. Height and diameter of shoots, number of leaves, fresh weight of the head and petiole, base diameter, dry weight of stem, petiole, and leaf were evaluated thirty-five days after transplantation. The total dry weight and leaf area were measured, and then we estimated the yield. There was a significant effect of soil cover and cultivar. In general, the cover with synthetic materials showed higher values on production of Pak Choi. The cultivar White Pak Choi was better adapted to the growing conditions, with an average yield of 57.78 t/ha.


HortScience ◽  
1991 ◽  
Vol 26 (6) ◽  
pp. 690E-690
Author(s):  
Daniel Patterson ◽  
William Hayslett ◽  
Sabrina Shaw

The objective of this study was to determine if different mulches would affect days to flowering or prolong the fall growth for tomatoes Lycopersicon esculentum. The mulches used were: black plastic, white plastic and straw. The tomatoes were transplanted to the field on 20 September 1990. Diurnal atmospheric and soil (just under the mulch) temperatures were taken at 12:00 noon. Average daily soil temperatures in September were 24°C, 22.5°C, 22°C and 21.5°C for black plastic, white plastic, the control, and straw respectively. Average soil temperatures ranged from 28.5°C for black plastic to 24.5°C for the straw treatments. Temperatures in October and November were 3 to 4 degrees lower for soils and between 4 to 7 degrees lower for the atmosphere. Average days to flowering were 68, 70, 68.5, and 75 for black plastic, white plastic, control, and straw treatments respectively. The average growth per plant were 20.5, 22.5, 25.9, and 12.5 centimeters for black plastic, white plastic. control. and straw respectively.


1989 ◽  
Vol 69 (3) ◽  
pp. 551-565
Author(s):  
F. SELLES ◽  
A. J. LEYSHON ◽  
C. A. CAMPBELL

Prairie farmers are interested in applying nitrogen (N) in the fall or winter to reduce fertilizer costs and allow a better distribution of labor and machinery use. Two studies were conducted in southwestern Saskatchewan to determine the consequences of applying N in late fall. In the laboratory, fertilizer N barely penetrated into the snow at constant subzero temperatures, but under freeze-thaw conditions, urea and ammonium nitrate descended 27 cm in 3 d. In the field, ammonium nitrate and urea were applied to snow-covered and bare microplots of grass sod and cereal stubble (1981–1982) and grass sod only (1985–1986). Nitrogen from ammonium nitrate penetrated deeper into the snow than N from urea. Nitrogen recovery in April 1982 was 55–59% from ammonium nitrate and 39–51% from urea, but was near 100% for both sources on bare soil treatments in April 1986. More N was recovered when fertilizer was applied to bare than to snow-covered soil, especially during 1985–1986 when all the applied fertilizer was blown off the snow-covered plots. Mineral N generally declined from fall to spring in all treatments, probably because of denitrification and immobilization. In 1985–1986, a period of extremely low temperatures in late fall resulted in no movement or transformation of N until after early December. By late January, periods of above-zero soil temperatures resulted in substantial mineralization of soil organic N, in the fertilized plots. This apparent priming effect was attributed to perturbations in the organic matter and microbial biomass due to fertilizer application and freezing and thawing. Following this period there was a general decrease in mineral N towards spring, as observed in 1981–1982. Producers must consider the benefits of using labor and equipment more efficiently and of lower fertilizer cost in the fall against the risk of large potential N losses over winter. Key words: Urea, ammonium nitrate, N recovery, frozen soils, fertilizing in winter


1982 ◽  
Vol 18 (2) ◽  
pp. 195-202 ◽  
Author(s):  
C. O. Othieno

SUMMARYDiurnal variations in soil temperature were measured under tea plants with different kinds of mulches. During the early years after planting temperatures differed, depending on the type of mulch and its heat absorptivity. Black plastic and stone chippings showed the greatest diurnal variations, but the variations disappeared in all treatments when there was a ≥ 60% canopy. Tea plants themselves modify soil temperatures, which could affect growth and yield in places where soil temperatures are generally lower.


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