scholarly journals Response of Pecan to Nitrogen Rate and Nitrogen Application Time

HortScience ◽  
2004 ◽  
Vol 39 (6) ◽  
pp. 1412-1415
Author(s):  
Michael W. Smith ◽  
Becky S. Cheary ◽  
Becky L. Carroll
Keyword(s):  
Nitrogen Application ◽  
Split Application ◽  
Single Application ◽  
Crop Failure ◽  
Nitrogen Rate ◽  
N Application ◽  
Fruit Thinning ◽  
Economic Practice ◽  
Leaf N Concentration ◽  
Leaf N

Nitrogen was applied between 1996 and 2002 to grafted `Mohawk' pecan (Carya illinoinensis Wangenh. C. Koch.) trees at 75 or 150 kg·ha-1 either as a single application in March or as a split application with 60% applied in March and 40% the first week of June. In 1997 and 2001, a spring freeze damaged developing shoots and buds, resulting in a small, noncommercial crop and the June portion of the N application was withheld. Nitrogen was also applied during the first week in October at 0 or 50 kg·ha-1 N if the crop load before fruit thinning in August was ≥40% fruiting shoots. There were few differences in the percentage of fruiting shoots or cluster size associated with N rate or applying N as a single or split application. Leaf N concentrations were either not affected by treatment or the results were inconsistent. Omitting the June application when a crop failure occurred did not affect the percentage of fruiting shoots the following year. October N application either did not affect or reduced the percentage of fruiting shoots the following year, and had no influence on leaf N concentration in July or October. These results indicate that the only advantage of a split N application is the option of withholding the second portion in the event of a crop failure. However, the added expense associated with splitting the N application versus the risk of crop failure must be assessed for each situation to determine if this is a sound economic practice. These data do not support an October N application when the crop is ≥40% fruiting shoots to reduce irregular bearing.

scholarly journals How Nitrogen Supply Affects Growth and Nitrogen Uptake, Use Efficiency, and Loss from Citrus Seedlings

1996 ◽  
Vol 121 (1) ◽  
pp. 105-114 ◽  
Author(s):  
John D. Lea-Cox ◽  
James P. Syvertsen
Keyword(s):  
Plant Growth ◽  
N Uptake ◽  
Single Application ◽  
N Application ◽  
N Supply ◽  
N Concentration ◽  
Leaf N Concentration ◽  
Use Efficiency ◽  
Complete Nutrient Solution ◽  
Leaf N

We examined how N supply affected plant growth and N uptake, allocation and leaching losses from a fine sandy soil with four Citrus rootstock species. Seedlings of `Cleopatra' mandarin (Citrus reticulata Blanco) and `Swingle' citrumelo (C. paradisi × P. trifoliata) were grown in a glasshouse in 2.3-liter pots of Candler fine sand and fertilized weekly with a complete nutrient solution containing 200 mg N/liter (20 mg N/week). A single application of 15NH415NO3(17.8% atom excess 15N) was substituted for a normal weekly N application when the seedlings were 22 weeks old (day O). Six replicate plants of each species were harvested at 0.5, 1.5, 3.5, 7, 11, and 30 days after 15N application. In a second experiment, NH4 NO3 was supplied at 18,53, and 105 mg N/week to 14-week-old `Volkamer' lemon (C. volkameriana Ten. & Pasq.) and sour orange (C. aurantium L.) seedlings in a complete nutrient solution for 8 weeks. A single application of 15NH415NO3 (23.0% 15N) was substituted at 22 weeks (day 0), as in the first experiment, and seedlings harvested 3,7, and 31 days after 15N application. Nitrogen uptake and partitioning were similar among species within each rate, but were strongly influenced by total N supply and the N demand by new growth. There was no 15N retranslocation to new tissue at the highest (105 mg N/week) rate, but N supplies below this rate limited plant growth without short-term 15N reallocation from other tissues. Leaf N concentration increased linearly with N supply up to the highest rate, while leaf chlorophyll concentration did not increase above that at 53 mg N/week. Photosynthetic CO2 assimilation was not limited by N in this study; leaf N concentration exceeded 100 mmol·m-2 in all treatments. Thus, differences in net productivity at the higher N rates appeared to be a function of increased leaf area, but not of leaf N concentration. Hence, N use efficiency decreased significantly over the range of N supply, whether expressed either on a gas-exchange or dry weight basis. Mean plant 15N uptake efficiencies after 31 days decreased from 60% to 47% of the 15N applied at the 18,20, and 53 mg N/week rates to less than 33% at the 105 mg N/week rate. Leaching losses increased with N rate, with plant growth rates and the subsequent N requirements of these Citrus species interacting with residual soil N and potential leaching loss.

scholarly journals Mulch Improves Pecan Tree Growth during Orchard Establishment

HortScience ◽  
2000 ◽  
Vol 35 (2) ◽  
pp. 192-195 ◽  
Author(s):  
Michael W. Smith ◽  
Becky L. Carroll ◽  
Becky S. Cheary
Keyword(s):  
Tree Height ◽  
Carya Illinoinensis ◽  
Split Application ◽  
Single Application ◽  
Trunk Diameter ◽  
Leaf N Concentration ◽  
K Concentration ◽  
N Rates ◽  
Leaf P ◽  
Leaf N

`Giles' pecan [Carya illinoinensis (Wangenh.) K. Koch] seedlings were either not mulched or mulched with wood chips arranged in a 1- or 2-m-wide square that was 30 cm deep. Mulch treatments were in factorial combination with two N rates applied as either a single application at budbreak or as a split application at budbreak and 3 weeks later. Tree height was positively related to mulch width each year of the 3-year study, and trunk diameter was positively related to mulch width during the second and third years of the experiment. Leaf P and K concentration during 2 years and leaf N during 1 year of the study were positively related to mulch width. Trees receiving the higher N rate were taller during 2 of 3 years, but leaf N concentration was not affected by N rate. No differences in the parameters measured were observed whether N was applied as a single or as a split application.

scholarly journals 291 Effect of Nitrogen Fertilization Time on Nitrogen Storage and Return Bloom of Pecan

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 492D-492
Author(s):  
Laura E. Acuña-Maldonado ◽  
Michael W. Smith
Keyword(s):  
Nitrogen Fertilization ◽  
Nitrogen Storage ◽  
Nitrogen Application ◽  
Application Time ◽  
Split Application ◽  
Single Application ◽  
N Application ◽  
Nitrate N ◽  
N Concentration ◽  
Return Bloom

A study was conducted to compare a single nitrogen application in March (125 kg N/ha) vs. a split application in March (75 kg N/ha) and October (50 kg N/ha) on 15-year-old `Maramec'. After one season, N application time did not affect return bloom. A split N application increased trunk wood Kjeldahl-N but decreased Kjeldahl-N in the current season's reproductive shoots and 1-year-old branches compared to a single application in March. Kjeldahl-N concentration was not affected by treatment in current season's vegetative shoots, trunk bark or roots. Nitrate-N concentration was not affected by treatment in any tissue sampled. Between the first week of October and the first killing frost in November, Kjeldahl-N increased 29% in current season's shoots, 21% in trunk bark, 32% in roots >1 cm in diameter, and 15% in roots <1 cm in diameter but decreased 42% in trunk wood and 5% in 1-year-old branches. Roots <1 cm in diameter accumulated more nitrate-N than other tissues during November.

scholarly journals Optimizing Nitrogen Application for Growth and Productivity of Pomegranates

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 366
Author(s):  
Silit Lazare ◽  
Yang Lyu ◽  
Uri Yermiyahu ◽  
Yehuda Heler ◽  
Alon Ben-Gal ◽  
...  
Keyword(s):  
N Uptake ◽  
N Fertilization ◽  
Field Conditions ◽  
Nitrogen Application ◽  
N Application ◽  
Environmentally Responsible ◽  
Irrigation Solution ◽  
Vegetative Indices ◽  
Leaf N ◽  
Usage Efficiency

Quantification of actual plant consumption of nitrogen (N) is necessary to optimize fertilization efficiency and minimize contamination of earth resources. We examined the performance of fruit-bearing pomegranate trees grown in soilless media and exposed to eight N-fertigation treatments, from 5 to 200 mg N L−1. Reproductive and vegetative indices were found to be optimal when 20 to 70 mg N L−1 was supplied. Nitrogen application levels over 70 mg L−1 reduced pomegranate development and reproduction. N uptake in low-level treatments was almost 100% and decreased gradually, down to 13% in 200 mg N L−1 treatment. N usage efficiency was maximized under 20 mg N L−1, in which case 80% to 90% of added N was taken up by the trees. At high N application, its efficiency was reduced with less than 50% utilized by the trees. Leaf N increased to a plateau as a function of increasing irrigation solution N, maximizing at ~15 to 20 mg N g−1. Therefore, analysis of diagnostic leaves is not a valid method to identify excessive detrimental N. The results should be valuable in the development of efficient, sustainable, environmentally responsible protocols for N fertilization in commercial pomegranate orchards, following adaptation and validation to real soil field conditions.

scholarly journals Estimating Plant Nitrogen Concentration of Maize Using a Leaf Fluorescence Sensor across Growth Stages

2020 ◽  
Vol 12 (7) ◽  
pp. 1139
Author(s):  
Rui Dong ◽  
Yuxin Miao ◽  
Xinbing Wang ◽  
Zhichao Chen ◽  
Fei Yuan ◽  
...  
Keyword(s):  
Precision Agriculture ◽  
Fluorescence Sensor ◽  
Accurate Estimation ◽  
Growth Stages ◽  
Fluorescence Sensors ◽  
N Application ◽  
N Concentration ◽  
Leaf N Concentration ◽  
N Status ◽  
Leaf N

Nitrogen (N) is one of the most essential nutrients that can significantly affect crop grain yield and quality. The implementation of proximal and remote sensing technologies in precision agriculture has provided new opportunities for non-destructive and real-time diagnosis of crop N status and precision N management. Notably, leaf fluorescence sensors have shown high potential in the accurate estimation of plant N status. However, most studies using leaf fluorescence sensors have mainly focused on the estimation of leaf N concentration (LNC) rather than plant N concentration (PNC). The objectives of this study were to (1) determine the relationship of maize (Zea mays L.) LNC and PNC, (2) evaluate the main factors influencing the variations of leaf fluorescence sensor parameters, and (3) establish a general model to estimate PNC directly across growth stages. A leaf fluorescence sensor, Dualex 4, was used to test maize leaves with three different positions across four growth stages in two fields with different soil types, planting densities, and N application rates in Northeast China in 2016 and 2017. The results indicated that the total leaf N concentration (TLNC) and PNC had a strong correlation (R2 = 0.91 to 0.98) with the single leaf N concentration (SLNC). The TLNC and PNC were affected by maize growth stage and N application rate but not the soil type. When used in combination with the days after sowing (DAS) parameter, modified Dualex 4 indices showed strong relationships with TLNC and PNC across growth stages. Both modified chlorophyll concentration (mChl) and modified N balance index (mNBI) were reliable predictors of PNC. Good results could be achieved by using information obtained only from the newly fully expanded leaves before the tasseling stage (VT) and the leaves above panicle at the VT stage to estimate PNC. It is concluded that when used together with DAS, the leaf fluorescence sensor (Dualex 4) can be used to reliably estimate maize PNC across growth stages.

scholarly journals Effect of Differential Rates of Nitrogen Fertilization on Subsequent Recovery of Isotopically Labeled Fertilizer Nitrogen by Mature Almond Trees

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 755F-755
Author(s):  
Steven A. Weinbaum ◽  
Wesley P. Asai ◽  
David A. Goldhamer ◽  
Franz J.A. Niederholzer ◽  
Tom T. Muraoka
Keyword(s):  
Fertilizer Application ◽  
N Fertilization ◽  
Fertilizer N ◽  
N Application ◽  
Fertilizer Nitrogen ◽  
Application Rates ◽  
Legitimate Concern ◽  
Almond Trees ◽  
Leaf N Concentration ◽  
Leaf N

There is legitimate concern that excessive fertilizer nitrogen (N) application rates adversely affect groundwater quality in the San Joaquin Valley of California. A 5-year study was conducted to assess the interrelationships between N fertilization rates, tree productivity, leaf [N], soil [NO–3], tree recovery of isotopically labeled fertilizer N, and NO–3 leaching. High N trees recovered <50% as much labeled fertilizer N in the crop as did trees previously receiving low to moderate fertilizer application rates. Our data suggest that the dilution of labeled N in the soil by high residual levels of NO–3 in the soil had a greater effect than tree N status (as expressed by leaf N concentration) on the relative recovery of fertilizer N.

RESPONSE OF AN ORCHARDGRASS-PERENNIAL RYEGRASS SWARD TO RATE AND METHOD OF UREA AND AMMONIUM NITRATE APPLICATION

1983 ◽  
Vol 63 (4) ◽  
pp. 719-725 ◽  
Author(s):  
A. A. BOMKE ◽  
R. A. BERTRAND
Keyword(s):  
Ammonium Nitrate ◽  
Perennial Ryegrass ◽  
Dry Matter ◽  
N Uptake ◽  
Split Application ◽  
Single Application ◽  
Forage Production ◽  
N Application ◽  
N Source ◽  
N Rates

Urea and ammonium nitrate were applied at rates of 75, 150 and 300 kg N/ha as either a single application in April or split into three equal increments, one applied in April and the second and third following cuts one and two. The orchardgrass-perennial ryegrass sward responded significantly to applied N in each year; however, the yield produced by the two sources differed in only one of the three years. In that year split applied ammonium nitrate gave 8% higher yields than similarly applied urea. The sources were found to be equivalent when applied in the spring. Split application of the N rates increased total annual dry matter yields in one of the three years regardless of N source. In all three years split application of N shifted forage production from cut one to cuts two and three. Key words: N uptake, split N application, orchardgrass-perennial ryegrass sward

scholarly journals Nitrogen Rate, Cultivar, and Within-row Spacing Affect Collard Yield and Leaf Nutrient Concentration

HortScience ◽  
1993 ◽  
Vol 28 (7) ◽  
pp. 701-703 ◽  
Author(s):  
James M. Dangler ◽  
C. Wesley Wood
Keyword(s):  
Mineral Nutrient ◽  
Nutrient Concentrations ◽  
Row Spacing ◽  
Nitrogen Rate ◽  
Fertilizer Rate ◽  
Rate Maximum ◽  
Leaf N Concentration ◽  
Leaf Nutrient Concentration ◽  
N Fertilizer Rate ◽  
Leaf N

Collards (Brassica oleracea L. Acephala Group) were grown in spring and fall to evaluate the effects of N fertilizer rate (0, 56, 112, 168, and 224 kg·ha -1), cultivar (Blue Max and Vates), and within-row spacing (15, 23, and 30 cm) on yield and leaf mineral nutrient concentrations. Season, cultivar, and N rate interacted in their effects on yield. In spring, `Blue Max' yield increased linearly with N rate to 10.4 t·ha-1, whereas the highest `Vates' yield (7.0 t·ha-1) was obtained with 112 kg N/ha, and yield remained similar with additional N. In fall, `Blue Max' and `Vates' yields were highest (14.5 and 9.9 t·ha -1, respectively) with 112 kg N/ha. Leaf N and P concentrations increased quadratically and linearly, respectively, in response to N rate. Maximum yields were obtained with the 15-cm within-row spacing. Leaf N concentration increased linearly with increased plant population. The adequacy of the present sufficiency range for leaf Ca concentrations of field-grown collards is discussed.

Fertilizing winter triticale “Timiryazevskaya 150” by nitrogen in the Central Non-Chernozem region

2019 ◽  
Author(s):  
А. Шаров ◽  
В. Игонин ◽  
В. Мельников ◽  
А. Бусурманкулов
Keyword(s):  
Crop Yield ◽  
Clay Content ◽  
Fertilization Rate ◽  
Nitrogen Fertilizers ◽  
Nitrogen Application ◽  
Split Application ◽  
Nitrogen Rate ◽  
Nitrogen Use ◽  
Winter Triticale ◽  
Experimental Station

Исследования проводись на Полевой опытной станции РГАУМСХА им. К. А. Тимирязева в 20162017 годах. В работе представлены результаты полевых опытов по внесению аммиачной селитры в различных сочетаниях с целью изучения эффективности применения азотной подкормки на озимой тритикале сорта Тимирязевская 150. В ходе проведения опытов определена количественная зависимость между урожаем зерна и внесением азота в возрастающих дозах в виде: Y 13,89 ln x 46,54. По величине максимальной урожайности (8,5 т/га) и показателям эффективности использования азота определена оптимальная доза удобрений (N120) для дерновоподзолистых среднесуглинистых почв. Применение азотной подкормки в виде разового внесения (N120), двукратного внесения (N6060) и трёхкратного внесения (N603030 N306030 и Nкр (70 20 10)) не выявило преимущества какоголибо варианта в сборе урожая. Очевидно экономическое преимущество разового внесения азота. Investigations took place at the Field Experimental Station of the Russian Timiryazev State Agrarian University in 20162017. The field trial aimed at testing the effectiveness of nitrogen fertilizers, applied as ammonium nitrate in various combinations on winter triticale Timiryazevskaya 150. Grain yield positively correlated with nitrogen rate: Y 13.89 ln x 46.54. N120 was shown to be the optimal fertilization rate resulting in yield of 8.5 t ha1 and effective nitrogen use on sodpodzolic soil with medium clay content. Split application of nitrogen once (N120), twice (N6060) and trice (N603030 N306030 and N (70 20 10) varied insignificantly in their influence on crop yield. Single nitrogen application was more effective economically.

Time of nitrogen application and yield of Bengal lychee on a sandy loam soil in subtropical Queensland

1994 ◽  
Vol 34 (6) ◽  
pp. 803 ◽  
Author(s):  
CM Menzel ◽  
GF Haydon ◽  
VJ Doogan ◽  
DR Simpson
Keyword(s):  
Sandy Loam ◽  
Leaf Growth ◽  
Co2 Assimilation ◽  
Sandy Loam Soil ◽  
N Application ◽  
Net Co2 Assimilation ◽  
Loam Soil ◽  
Leaf N Concentration ◽  
Fertiliser Application ◽  
Leaf N

Nitrogen (N) was applied over 4 years to 6-year-old lychee trees (Litchi chinensis Sonn. cv. Bengal) growing in subtropical Queensland (lat. 27�S.) on a sandy loam soil (0-15 cm) with 2.8 mg nitrate-N/kg, to determine the effect of time of N application on leaf N concentration, vegetative growth, flowering, and yield. Applications of N (equivalent to 750 kg N/ha in year 4) were made after panicle emergence in July, after harvest in January, or split between the 2 periods. Control trees received no N. Leaf N concentrations in April-June were, on average, about 0.1% lower after a single N application in winter than application in summer or split applications. Leaf N concentrations in November-February were about 0.1% higher after winter or split N applications than after summer applications. Timing of fertiliser application had no affect on yield. It took 4 years without N fertiliser to show significant reductions in yield compared with fertilised trees. In year 4, yield increased from 20 to 60 kg/tree on individual pairs of trees as leaf N in August increased from 0.95 to 1.56%. Lower yields in control trees in year 4 were associated with poor leaf growth in the previous 2 years, and with lower concentrations of N in the panicles, leaves, twigs, and small branches, as well as lower chlorophyll concentrations and net CO2 assimilation after fruit set, compared with trees receiving N.

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