scholarly journals Spraying Leaves of Pear Nursery Trees with Urea and Copper Ethylenediaminetetraacetic Acid Alters Tree Nitrogen Concentration without Influencing Tree Susceptibility to Phytophthora syringae

2010 ◽  
Vol 20 (2) ◽  
pp. 331-342 ◽  
Author(s):  
S. Laywisadkul ◽  
C.F. Scagel ◽  
L.H. Fuchigami ◽  
R.G. Linderman
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Nitrogen Concentration ◽  
N Availability ◽  
Soil N ◽  
N Content ◽  
Soil N Availability ◽  
Susceptibility To Infection ◽  
N Concentration ◽  
Nursery Trees ◽  
The Relationship

Recent field observations by growers suggest that increased nitrogen (N) content in nursery trees resulting from foliar sprays with urea in the autumn increases tree susceptibility to infection by Phytophthora syringae. We investigated the effects of soil N availability and spraying pear (Pyrus communis ‘OHF 97’) trees with combinations of urea, chelated copper ethylenediaminetetraacetic acid (CuEDTA), and phosphonate-containing fungicides on stem N concentration and susceptibility to infection by P. syringae. Increasing soil N availability increased susceptibility to P. syringae and increased N and amino acid concentration in stems. Spraying trees with urea in the autumn increased concentrations of N and amino acids in stems and had no significant effect on tree susceptibility when stems were inoculated with P. syringae before or after urea sprays. Spraying trees with CuEDTA decreased stem N concentrations and had no significant influence on tree susceptibility to P. syringae when stems were inoculated before or after CuEDTA sprays. These results suggest the relationship between tree susceptibility to P. syringae and tree N concentration may be specific to the form of N, delivery method, or timing of N applications. Trees had higher N concentrations in stems in November than in October and were more susceptible to P. syringae when inoculated in November, suggesting that environmental factors and increasing tree dormancy may be responsible for changes in susceptibility to the pathogen. Spraying trees with fungicides containing fosetyl-aluminum in October or November decreased tree susceptibility to P. syringae. The effects of fungicides containing fosetyl-aluminum on susceptibility were similar regardless of whether trees were sprayed or not with urea or CuEDTA, suggesting that these fungicides can be used in combination with urea or CuEDTA sprays for reducing disease severity caused by P. syringae without impacting growers' objective of increasing tree N content with urea or enhancing early defoliation with CuEDTA.

scholarly journals Effect of Winter Cover Crops on Soil Nitrogen Availability, Corn Yield, and Nitrate Leaching

2001 ◽  
Vol 1 ◽  
pp. 22-29 ◽  
Author(s):  
S. Kuo ◽  
B. Huang ◽  
R. Bembenek
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
N Fertilizer ◽  
N Leaching ◽  
Corn Yield ◽  
N Availability ◽  
Soil N ◽  
Soil N Availability ◽  
N Concentration ◽  
Fertilizer Rates

Biculture of nonlegumes and legumes could serve as cover crops for increasing main crop yield, while reducing NO3leaching. This study, conducted from 1994 to 1999, determined the effect of monocultured cereal rye (Secale cereale L.), annual ryegrass (Lolium multiflorum), and hairy vetch (Vicia villosa), and bicultured rye/vetch and ryegrass/vetch on N availability in soil, corn (Zea mays L.) yield, and NO3-N leaching in a silt loam soil. The field had been in corn and cover crop rotation since 1987. In addition to the cover crop treatments, there were four N fertilizer rates (0, 67, 134, and 201 kg N ha-1, referred to as N0, N1, N2, and N3, respectively) applied to corn. The experiment was a randomized split-block design with three replications for each treatment. Lysimeters were installed in 1987 at 0.75 m below the soil surface for leachate collection for the N0, N2, and N3treatments. The result showed that vetch monoculture had the most influence on soil N availability and corn yield, followed by the bicultures. Rye or ryegrass monoculture had either no effect or an adverse effect on corn yield and soil N availability. Leachate NO3-N concentration was highest where vetch cover crop was planted regardless of N rates, which suggests that N mineralization of vetch N continued well into the fall and winter. Leachate NO3-N concentration increased with increasing N fertilizer rates and exceeded the U.S. Environmental Protection Agency’s drinking water standard of 10 mg N l�1 even at recommended N rate for corn in this region (coastal Pacific Northwest). In comparisons of the average NO3-N concentration during the period of high N leaching, monocultured rye and ryegrass or bicultured rye/vetch and ryegrass/vetch very effectively decreased N leaching in 1998 with dry fall weather. The amount of N available for leaching (determined based on the presidedress nitrate test, the amount of N fertilizer applied, and N uptake) correlated well with average NO3-N during the high N leaching period for vetch cover crop treatment and for the control without the cover crops. The correlation, however, failed for other cover crops largely because of variable effectiveness of the cover crops in reducing NO3leaching during the 5 years of this study. Further research is needed to determine if relay cover crops planted into standing summer crops is a more appropriate approach than fall seeding in this region to gain sufficient growth of the cover crop by fall. Testing with other main crops that have earlier harvest dates than corn is also needed to further validate the effectiveness of the bicultures to increase soil N availability while protecting the water quality.

Long-term increase of nitrogen availability from fertilization of Douglas-fir

1985 ◽  
Vol 15 (4) ◽  
pp. 723-724 ◽  
Author(s):  
Dan Binkley ◽  
Paula Reid
Keyword(s):  
Leaf Area ◽  
Nitrogen Availability ◽  
Nitrogen Concentration ◽  
The United States ◽  
Douglas Fir ◽  
Stem Growth ◽  
N Availability ◽  
Soil N ◽  
Fertilizer Response ◽  
Soil N Availability

Most Douglas-fir stands respond to nitrogen fertilization by increasing stem growth for less than 8 years, but one plantation at the United States Forest Service Wind River Experimental Forest has responded for over 15 years. The nitrogen concentration of foliage and fresh litter were higher in the fertilized (applied at 470 kg N/ha) plots 18 years after fertilization. Retranslocation of N from senescent needles was not affected and stem growth per unit N in the canopy was similar between unfertilized and fertilized plots. An index of soil N availability in the fertilized plots was twice that of unfertilized plots. The higher stem growth, leaf area, and stem growth per unit leaf area appeared related to a sustained increase in soil N availability rather than increased N-use efficiency. Soil N transformation processes need to be examined to complete the explanation of the unusually prolonged fertilizer response in these plots.

scholarly journals Development of an Online Tool for Tracking Soil Nitrogen to Improve the Environmental Performance of Maize Production

2021 ◽  
Vol 13 (10) ◽  
pp. 5649
Author(s):  
Giovani Preza-Fontes ◽  
Junming Wang ◽  
Muhammad Umar ◽  
Meilan Qi ◽  
Kamaljit Banger ◽  
...  
Keyword(s):  
Real Time ◽  
N Uptake ◽  
Growing Season ◽  
Weather Data ◽  
N Availability ◽  
Soil N ◽  
N Losses ◽  
Online Tool ◽  
Support Tool ◽  
Soil N Availability

Freshwater nitrogen (N) pollution is a significant sustainability concern in agriculture. In the U.S. Midwest, large precipitation events during winter and spring are a major driver of N losses. Uncertainty about the fate of applied N early in the growing season can prompt farmers to make additional N applications, increasing the risk of environmental N losses. New tools are needed to provide real-time estimates of soil inorganic N status for corn (Zea mays L.) production, especially considering projected increases in precipitation and N losses due to climate change. In this study, we describe the initial stages of developing an online tool for tracking soil N, which included, (i) implementing a network of field trials to monitor changes in soil N concentration during the winter and early growing season, (ii) calibrating and validating a process-based model for soil and crop N cycling, and (iii) developing a user-friendly and publicly available online decision support tool that could potentially assist N fertilizer management. The online tool can estimate real-time soil N availability by simulating corn growth, crop N uptake, soil organic matter mineralization, and N losses from assimilated soil data (from USDA gSSURGO soil database), hourly weather data (from National Weather Service Real-Time Mesoscale Analysis), and user-entered crop management information that is readily available for farmers. The assimilated data have a resolution of 2.5 km. Given limitations in prediction accuracy, however, we acknowledge that further work is needed to improve model performance, which is also critical for enabling adoption by potential users, such as agricultural producers, fertilizer industry, and researchers. We discuss the strengths and limitations of attempting to provide rapid and cost-effective estimates of soil N availability to support in-season N management decisions, specifically related to the need for supplemental N application. If barriers to adoption are overcome to facilitate broader use by farmers, such tools could balance the need for ensuring sufficient soil N supply while decreasing the risk of N losses, and helping increase N use efficiency, reduce pollution, and increase profits.

Nitrous oxide emissions from red clover and winter wheat residues depend on interacting effects of distribution, soil N availability and moisture level

2021 ◽  
Author(s):  
Arezoo Taghizadeh-Toosi ◽  
Baldur Janz ◽  
Rodrigo Labouriau ◽  
Jørgen E. Olesen ◽  
Klaus Butterbach-Bahl ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Winter Wheat ◽  
Red Clover ◽  
Moisture Level ◽  
Nitrous Oxide Emissions ◽  
N Availability ◽  
Soil N ◽  
Soil N Availability

scholarly journals Atmospheric CO 2 , Soil-N Availability, and Allocation of Biomass and Nitrogen by Populus tremuloides

2000 ◽  
Vol 10 (1) ◽  
pp. 34 ◽  
Author(s):  
Donald R. Zak ◽  
Kurt S. Pregitzer ◽  
Peter S. Curtis ◽  
Christoph S. Vogel ◽  
William E. Holmes ◽  
...  
Keyword(s):  
Populus Tremuloides ◽  
N Availability ◽  
Soil N ◽  
Soil N Availability

scholarly journals LEAF TOTAL NITROGEN CONCENTRATION AS AN INDICATOR OF NITROGEN STATUS FOR PLANTLETS AND YOUNG PLANTS OF EUCALYPTUS CLONES

2015 ◽  
Vol 39 (4) ◽  
pp. 1127-1140 ◽  
Author(s):  
Eric Victor de Oliveira Ferreira ◽  
Roberto Ferreira Novais ◽  
Bruna Maximiano Médice ◽  
Nairam Félix de Barros ◽  
Ivo Ribeiro Silva
Keyword(s):  
Total Nitrogen ◽  
Block Design ◽  
Nitrogen Concentration ◽  
Soil N ◽  
Total N ◽  
Chlorophyll Meter ◽  
N Concentration ◽  
Total Nitrogen Concentration ◽  
N Status ◽  
Leaf N

The use of leaf total nitrogen concentration as an indicator for nutritional diagnosis has some limitations. The objective of this study was to determine the reliability of total N concentration as an indicator of N status for eucalyptus clones, and to compare it with alternative indicators. A greenhouse experiment was carried out in a randomized complete block design in a 2 × 6 factorial arrangement with plantlets of two eucalyptus clones (140 days old) and six levels of N in the nutrient solution. In addition, a field experiment was carried out in a completely randomized design in a 2 × 2 × 2 × 3 factorial arrangement, consisting of two seasons, two regions, two young clones (approximately two years old), and three positions of crown leaf sampling. The field areas (regions) had contrasting soil physical and chemical properties, and their soil contents for total N, NH+4-N, and NO−3-N were determined in five soil layers, up to a depth of 1.0 m. We evaluated the following indicators of plant N status in roots and leaves: contents of total N, NH+4-N, NO−3-N, and chlorophyll; N/P ratio; and chlorophyll meter readings on the leaves. Ammonium (root) and NO−3-N (root and leaf) efficiently predicted N requirements for eucalyptus plantlets in the greenhouse. Similarly, leaf N/P, chlorophyll values, and chlorophyll meter readings provided good results in the greenhouse. However, leaf N/P did not reflect the soil N status, and the use of the chlorophyll meter could not be generalized for different genotypes. Leaf total N concentration is not an ideal indicator, but it and the chlorophyll levels best represent the soil N status for young eucalyptus clones under field conditions.

scholarly journals INTERACTIVE EFFECTS OF ATMOSPHERIC CO2AND SOIL-N AVAILABILITY ON FINE ROOTS OFPOPULUS TREMULOIDES

2000 ◽  
Vol 10 (1) ◽  
pp. 18-33 ◽  
Author(s):  
Kurt S. Pregitzer ◽  
Donald R. Zak ◽  
Jennifer Maziasz ◽  
Jared DeForest ◽  
Peter S. Curtis ◽  
...  
Keyword(s):  
Fine Roots ◽  
Interactive Effects ◽  
N Availability ◽  
Soil N ◽  
Soil N Availability
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