scholarly journals A Petiole Sap Nitrate Test for Cauliflower

HortScience ◽  
1996 ◽  
Vol 31 (6) ◽  
pp. 934-937 ◽  
Author(s):  
Aki Kubota ◽  
Thomas L. Thompson ◽  
Thomas A. Doerge ◽  
Ronald E. Godin
Keyword(s):  
Application Rate ◽  
Nitrate Ion ◽  
Growing Seasons ◽  
Water Rates ◽  
Nitrate Determination ◽  
N Rates ◽  
The Relationship ◽  
Crop Maturity ◽  
Petiole Sap ◽  
Sap Test

This study was conducted to evaluate the accuracy of sap analysis using a portable nitrate ion meter for cauliflower (Brassica oleracea L. Botrytis Group, cv. Candid Charm) petiole nitrate determination. The relationship between NO3-N concentration in fresh petiole sap and in dried petiole tissue was studied for cauliflower grown in southern Arizona during the 1993–94 and 1994–95 growing seasons. Experiments were factorial combinations of three water rates and four N rates, both ranging from deficient to excessive. Petioles were collected throughout each season and were split for analysis of sap NO3-N and dried petiole NO3-N. Linear correlations between the two methods were similar in both seasons, with no consistent effect due to water application rate or crop maturity. Therefore, a single regression equation was derived: petiole sap NO3-N (mg·liter–1) = 0.047 × dry petiole NO3-N (mg·kg–1) + 218 (r2 = 0.772). This equation can be used to relate sap test measurements to existing guidelines for NO3-N concentrations in cauliflower petioles. These results suggest that the quick sap test, using the portable nitrate ion meter, is a valuable technique for monitoring N status of cauliflower.

scholarly journals SAP NITRATE TESTING FOR IMPROVED NITROGEN MANAGEMENT ON POTATOES

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 614b-614 ◽  
Author(s):  
Maurice L. Vitosh ◽  
George H. Silva ◽  
Richard D. Leep ◽  
David S. Douches
Keyword(s):  
Rapid Determination ◽  
Tuber Initiation ◽  
Yield Response ◽  
Nitrate Level ◽  
Fertilizer Rate ◽  
N Rates ◽  
Petiole Sap ◽  
Sap Test ◽  
N Fertilizer Rate

A procedure for rapid determination of nitrate in the fresh petiole sap using an ion specific electrode was developed. A highly significant correlation (R2-0.92) was obtained between the nitrate measured by the sap test and the conventional oven-dried tissue method. The effects of five nitrogen(N) rates ranging from 0 to 268 kg ha-1, and five dates of sampling dates beginning at tuber initiation, on the sap nitrate concentration were investigated. The nitrate level increased in proportion to N fertilizer rate. The nitrate level was generally higher at tuber initiation and decreased as the season progressed. The rate of decrease was related to the N supply in the soil. At N rates of 0 and 67 Kg ha-1, the average weekly decrease in the nitrate level was greater than 100 ppm. Based on yield response, the nitrate levels were partitioned as deficient adequate and excessive, and a critical nutrient range was established. The sap test offers a tactical approach for corrective in-season fertilization and a means to increase the efficiency of both fertilizer and available soil N.

Nitrogen fertilization of grass seed crops as related to soil mineral nutrition.

1988 ◽  
Vol 36 (4) ◽  
pp. 375-385
Author(s):  
W.J.M. Meijer ◽  
S. Vreeke
Keyword(s):  
Field Experiments ◽  
Poa Pratensis ◽  
Application Rate ◽  
Early Spring ◽  
Soil Mineral ◽  
Mineral N ◽  
Yield Responses ◽  
Seed Crops ◽  
N Rates ◽  
The Relationship

The relationship between the level of soil mineral N present in early spring and the economically optimum application rate of N fertilizer was investigated in field experiments in 1978-84 at 4 locations in the Netherlands with Lolium perenne, Poa pratensis and Festuca rubra. Spring dressings, as split and single applications, of 30-210 kg N/ha and autumn dressings of 0-90 kg N/ha were used. The optimum spring rates were linearly related to mineral N in the 0-90 cm soil layers in L. perenne. No such relationship existed for the other species. The economically optimum spring N rates were 110 and 84 kg/ha, and yields were highest with autumn N dressings of 60 and 30 kg/ha for P. pratensis and F. rubra, resp. Autumn dressing had no effect on L. perenne if the spring dressing was near or above the optimum. A split spring dressing produced greater vegetative regrowth and reduced yields. Seed yield responses to fertilization were related to number of inflorescences produced rather than weight of seed per inflorescence. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Nitrous oxide and carbon dioxide emissions from monoculture and rotational cropping of corn, soybean and winter wheat

2008 ◽  
Vol 88 (2) ◽  
pp. 163-174 ◽  
Author(s):  
C F Drury ◽  
X M Yang ◽  
W D Reynolds ◽  
N B McLaughlin
Keyword(s):  
Carbon Dioxide ◽  
Nitrous Oxide ◽  
Winter Wheat ◽  
Carbon Dioxide Emissions ◽  
Crop Residue ◽  
Agricultural Land ◽  
Application Rate ◽  
Climatic Conditions ◽  
Growing Seasons ◽  
Previous Crop

It is well established that nitrous oxide (N2O) and carbon dioxide (CO2) emissions from agricultural land are influenced by the type of crop grown, the form and amount of nitrogen (N) applied, and the soil and climatic conditions under which the crop is grown. Crop rotation adds another dimension that is often overlooked, however, as the crop residue being decomposed and supplying soluble carbon to soil biota is usually from a different crop than the crop that is currently growing. Hence, the objective of this study was to compare the influence of both the crop grown and the residues from the preceding crop on N2O and CO2 emissions from soil. In particular, N2O and CO2 emissions from monoculture cropping of corn, soybean and winter wheat were compared with 2 -yr and 3-yr crop rotations (corn-soybean or corn-soybean-winter wheat). Each phase of the rotation was measured each year. Averaged over three growing seasons (from April to October), annual N2O emissions were about 3.1 to 5.1 times greater in monoculture corn (2.62 kg N ha-1) compared with either monoculture soybean (0.84 kg N ha-1) or monoculture winter wheat (0.51 kg N ha-1). This was due in part to the higher inorganic N levels in the soil resulting from the higher N application rate with corn (170 kg N ha-1) than winter wheat (83 kg N ha-1) or soybean (no N applied). Further, the previous crop also influenced the extent of N2O emissions in the current crop year. When corn followed corn, the average N2O emissions (2.62 kg N ha-1) were about twice as high as when corn followed soybean (1.34 kg N ha-1) and about 60% greater than when corn followed winter wheat (1.64 kg N ha-1). Monoculture winter wheat had about 45% greater CO2 emissions than monoculture corn or 51% greater emissions than monoculture soybean. In the corn phase, CO2 emissions were greater when the previous crop was winter wheat (5.03 t C ha-1) than when it was soybean (4.20 t C ha-1) or corn (3.91 t C ha-1). Hence, N2O and CO2 emissions from agricultural fields are influenced by both the current crop and the previous crop, and this should be accounted for in both estimates and forecasts of the emissions of these important greenhouse gases. Key words: Denitrification, soil respiration, rotation, crop residue

Soil inorganic nitrogen content in commercial potato fields in New Brunswick

2003 ◽  
Vol 83 (4) ◽  
pp. 425-429 ◽  
Author(s):  
B. J. Zebarth ◽  
Y. Leclerc ◽  
G. Moreau ◽  
R. Gareau ◽  
P. H. Milburn
Keyword(s):  
Root Zone ◽  
Inorganic Nitrogen ◽  
Solanum Tuberosum L ◽  
Red Clover ◽  
Application Rate ◽  
Inorganic N ◽  
N Content ◽  
Growing Seasons ◽  
Commercial Potato ◽  
Soil Inorganic

Information on inorganic N content in commercial potato fields in Atlantic Canada is limited. Soil inorganic N measurements were collected from 228 commercial potato fields from 1999 to 2001. Soil NO3 content to 30 cm depth at planting ranged from 2 to 124 kg N ha-1, and was generally higher for preceding potato, red clover, or hay crops compared to preceding cereal or other crops. Soil NH4 content to 30 cm depth measured at planting ranged from 3 to 64 kg N ha-1, indicating that both soil NO3 and NH4 need to be measured to assess plant-available soil N content in spring. Soil NO3 content to 30-cm depth at tuber harvest ranged from 3 to 250 kg N ha-1, generally increased with increasing fertilizer N application rate, and differed among different potato cultivars. Soil NO3 content measured to 30-cm depth in spring ranged from 3 to 100% of soil NO3 at harvest in the preceding fall, indicating that highly variable losses of soil NO3 from the root zone occur between growing seasons. Key words: Nitrate, ammonium, Solanum tuberosum L.

scholarly journals The influence of low temperatures on the incidence of sugary disease on sorghum

2006 ◽  
Vol 36 (2) ◽  
pp. 397-403
Author(s):  
Amauri Bogo ◽  
Ricardo Trezi Casa ◽  
Luis Sangoi ◽  
Paulo Tarcísio Domatos Borba
Keyword(s):  
Low Temperatures ◽  
Disease Incidence ◽  
Climatic Conditions ◽  
Male Sterile ◽  
Growing Seasons ◽  
Claviceps Africana ◽  
Sorghum Genotypes ◽  
Fertile Hybrids ◽  
The Relationship ◽  
Increased Susceptibility

The relationship between pre-flowering climatic conditions and sugary disease incidence was quantified in grain and forage sorghum genotypes at two sowing periods (mid November and mid December). The trials were carried out over the 2001/02 and 2002/03 growing seasons, in Lages, Santa Catarina State. Four commercial male-fertile sorghum hybrids (BR 600-forrage, BR 700-grain, BR 701-forage/silage and BR 800-forage) and one male-sterile inbred line (BR 001-A) were evaluated. When each genotype reached the flowering stage, 50 panicles were marked and sprayed with a suspension of Claviceps africana (1,000 spores mL-1). Air temperature, humidity and rainfall were recorded through out the growing cycle. Low temperatures three to four weeks prior to flowering, increased susceptibility. At both sowing periods, average night temperatures lower than 15°C during the critical period of pre-flowering turned the fertile hybrids as susceptible as the male-sterile inbred to ergot infection. The tested hybrids differed in their ability to tolerate pre-flowering cold stress. Seed set in uninoculated heads under pollination bags was also reduced, suggesting that increased susceptibility to sugary disease was the result of low temperature induced sterility.

scholarly journals Temperature and Wetness-Duration Requirements for Grape Leaf and Cane Infection by Phomopsis viticola

Plant Disease ◽  
2003 ◽  
Vol 87 (7) ◽  
pp. 832-840 ◽  
Author(s):  
O. Erincik ◽  
L. V. Madden ◽  
D. C. Ferree ◽  
M. A. Ellis
Keyword(s):  
Disease Severity ◽  
Correlation Coefficients ◽  
Phomopsis Viticola ◽  
Average Temperature ◽  
Growing Seasons ◽  
Wide Range ◽  
Maximum Temperatures ◽  
Rain Events ◽  
Grape Leaf ◽  
The Relationship

In 1998 and 1999, controlled-environment studies were conducted in growth chambers to determine the temperature and wetness-duration parameters required for leaf and cane infection of grape by Phomopsis viticola. Greenhouse-grown ‘Catawba’ (Vitis labrusca) and ‘Seyval’ (French hybrid) grapes were inoculated with P. viticola and incubated at constant temperatures of 5, 10, 15, 20, 25, 30, and 35°C and at wetness durations of 5, 10, 15, and 20 h for each temperature. Data from each cultivar were analyzed by nonlinear regression analysis to determine the relationship between disease severity and temperature and wetness duration. A generalized form of the Analytis Beta model was found to provide the best fit to the data. Disease severity on leaves and canes increased with increasing wetness duration at most temperatures. Minimum and maximum temperatures for infection were around 5 and 35.5°C, respectively. Optimum temperatures for leaf and cane infection were between 16 and 20°C. In the 2000 and 2001 growing seasons, the generalized Beta model was validated in ‘Catawba’ and ‘Seyval’ vineyards by inoculating vines during natural rain events. Average temperature and hours of wetness for each event and inoculation were recorded and used in the model equation to predict disease severity on leaves and internodes. Correlation coefficients between observed disease severities following field inoculations and predicted disease severities for both cultivars were between 0.71 and 0.81 and always significant (P < 0.01). These results indicate that the model reliably predicted leaf and cane infection on both cultivars over a wide range of wetness durations and temperatures. The model may be useful in developing disease-forecasting systems for Phomopsis cane and leaf spot on grapes.

scholarly journals Pre-anthesis development of winter wheat and barley and relationships with grain yield

2018 ◽  
Vol 64 (No. 7) ◽  
pp. 310-316 ◽  
Author(s):  
Mirosavljevic Milan ◽  
Momcolovic Vojislava ◽  
Maksimovic Ivana ◽  
Putnik-Delic Marina ◽  
Pržulj Novo ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Sowing Date ◽  
Wheat Cultivars ◽  
Growing Seasons ◽  
Sowing Dates ◽  
Winter Wheat Cultivars ◽  
Leaf Appearance ◽  
Relationship Of ◽  
The Relationship

The aim of this study was to improve understanding of (1) the effect of genotypic and environmental factors on pre-anthesis development and leaf appearance traits of barley and wheat; (2) the relationship of these factors with grain yield, and (3) the differences between these two crops across different environments/sowing dates. Therefore, trials with six two-row winter barley and six winter wheat cultivars were carried out in two successive growing seasons on four sowing dates. Our study showed that the observed traits varied between species, cultivars and sowing dates. In both growing seasons, biomass at anthesis and grain yield declined almost linearly by delaying the sowing date. There was no clear advantage in grain yield of wheat over barley under conditions of later sowing dates. Generally, barley produced more leaf and had shorter phyllochron than wheat. Both wheat and barley showed a similar relationship between grain yield and different pre-anthesis traits.

scholarly journals The effects of precipitation variability on the canopy cover of forage species in arid rangelands, Iran

2020 ◽  
Vol 13 (18) ◽  
Author(s):  
Hamed Joneidi ◽  
Nahid Azizi ◽  
Khaled Osati ◽  
Isa Bandak
Keyword(s):  
Linear Regression ◽  
Confidence Level ◽  
Canopy Cover ◽  
Floristic Composition ◽  
Linear Regression Models ◽  
Growing Seasons ◽  
Arid Rangelands ◽  
Annual Plant Species ◽  
The Relationship ◽  
Precipitation And Temperature

Abstract This research was conducted to monitor changes in canopy cover of typical species during a 10-year period in the part of arid rangelands, to find out the relationship between two important climate variables (precipitation and temperature) and canopy cover changes. For that reason, canopy cover percentages of six dominant perennials and all annual plant species combined were measured during a 10-year period at phenological maturity of plant in thirty 2 m × 2 m plots which were placed along two 250-m transect lines. The results demonstrated that the maximum canopy cover for water year 2006–2007 (wet year) and the minimum value for water year 2012–2013 (drought) were 15 and 5.5%, respectively. The canopy cover was modeled by linear regression in which precipitation and temperature variables were considered independent variables. April precipitation explained 65% of changes in the canopy cover percentage of Artemisia sieberi at 95% confidence level (RRMSE = 0.26 and MAE = 0.49). The best simple linear regression models for estimating canopy cover percentages of Stipa barbata and Zygophyllum eurypterum corresponded to cumulative 4-month precipitation from March to June and March precipitation respectively, representing 77% (at 99% confidence level) and 67% (at 95% confidence level) of changes correspondingly. Considering the dominance of A. sieberi, S. barbata, and Z. eurypterum in floristic composition of the study area, it can be concluded that most changes in canopy cover of the studied rangeland are predicted by variability of precipitation during growing seasons.

The incidence of bacterial blights of French bean (Phaseolus vulgaris) in East Gippsland, Victoria

1978 ◽  
Vol 18 (91) ◽  
pp. 318
Author(s):  
DLS Wimalajeewa ◽  
RJ Nancarrow
Keyword(s):  
Phaseolus Vulgaris ◽  
Severe Disease ◽  
French Bean ◽  
Brown Spot ◽  
French Beans ◽  
Halo Blight ◽  
Growing Seasons ◽  
Relationship Of ◽  
The Relationship

The incidence of common blight, halo blight and brown spot on French beans was surveyed in the Bairnsdale-Lindenow and Orbost areas in East Gippsland during the 1975-76 and 1976-77 growing seasons. Common blight and halo blight were severe only during late January to March, and occurred largely on mature crops. Common blight was the more severe disease in the Orbost area whereas halo blight was more severe in the Bairnsdale-Lindenow area. Brown spot occurred throughout the season on crops of all ages in both areas but was more severe in the Bairnsdale-Lindenow area. The relationship of weather to the incidence of bacterial blights in the two areas is discussed. It is inferred that losses due to common blight and halo blight could be considerably minimized by timing the planting of crops to harvest them by mid-February.

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