Effects of rates and timing of nitrogen fertilizer on disease control by fungicides in winter wheat. 2. Crop growth and disease development

2003 ◽  
Vol 140 (1) ◽  
pp. 15-29 ◽  
Author(s):  
J. E. OLESEN ◽  
L. N. JØRGENSEN ◽  
J. PETERSEN ◽  
J. V. MORTENSEN
Keyword(s):  
Powdery Mildew ◽  
Leaf Spot ◽  
Spectral Reflectance ◽  
Dry Matter ◽  
Disease Development ◽  
N Application ◽  
Leaf N Concentration ◽  
Canopy Size ◽  
Leaf N ◽  
Septoria Leaf Spot

Data from a two-factorial experiment carried out during 3 years were used to analyse the effects of crop nitrogen (N) status on disease development, and the effects of N supply and disease on light interception (IPAR) and radiation use efficiency (RUE) in winter wheat (Triticum aestivum). The factors in the experiment comprised seven strategies of N fertilizer application including different N rates and timing of application, and five doses of fungicide application for control of the leaf diseases powdery mildew (Blumeria graminis) and septoria leaf spot (Septoria tritici). Light interception was estimated from weekly measurements of crop spectral reflectance. The increase of crop dry matter was mainly affected by N fertilizer and disease through effects on IPAR. Early N application increased IPAR and thus dry matter growth more than later N application. A split N strategy may ensure both high N uptake and high growth rates of the crop. Only septoria leaf spot significantly reduced RUE. Septoria leaf spot was found to be up to nine times more detrimental to grain yield than powdery mildew for similar severity levels. Fungicide applications may therefore be reduced in cases of low powdery mildew severity combined with low crop susceptibility to this disease. This low susceptibility was found to be obtainable with split N application strategies, as the severity of both powdery mildew and septoria leaf spot increased with increasing leaf N concentration. A similar but smaller correlation was obtained between disease severity and canopy size. Measurements of canopy size using spectral reflectance may be used as a simple indicator of general crop susceptibility to disease, whereas measurements of leaf N concentration may be used as input into decision support systems for fungicide application.

scholarly journals Inoculation and N Fertilization Affect the Dry Matter, N Fixation, and Bioactive Compounds in Sulla Leaves

Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 289 ◽  
Author(s):  
Leonardo Sulas ◽  
Giuseppe Campesi ◽  
Giovanna Piluzza ◽  
Giovanni A. Re ◽  
Paola A. Deligios ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Dry Matter ◽  
Seed Set ◽  
Natural Habitat ◽  
N Fertilization ◽  
N Fixation ◽  
N Application ◽  
Uninoculated Control ◽  
The Relationship ◽  
Leaf N

Sulla (Sulla coronaria [L.] Medik), a Mediterranean short-lived legume with tolerance to drought-prone environments, requires inoculation outside its natural habitat. Its leaves are appreciated for the bromatological composition and content of bioactive compounds. However, no information is available regarding the distinct effects of inoculation and nitrogen (N) applications on leaf dry matter (DM), fixed N, and bioactive compounds. Sulla leaves were sampled from the vegetative stage to seed set in Sardinia (Italy) during 2013–2014 and leaf DM, N content, and fixed N were determined. Compared to the best performing inoculated treatments, DM yield and fixed N values of the control only represented 8% to 20% and 2% to 9%, respectively. A significant relationship between fixed N and leaf DM yield was established, reaching 30 kg fixed N t–1 at seed set. Significant variations in leaf atom% 15N excess and %Ndfa quantified decreases in leaf N fixation coupled with N application. Moreover, the petiole content of phenolic compounds markedly increased in the uninoculated control, suggesting deeper investigations on the relationship between bioactive compounds and inoculation treatments. Results highlighted substantial variation in DM, N yields, N-fixation ability, and content of bioactive compounds of sulla leaves caused by inoculation and N fertilization.

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 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 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.

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.

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.

scholarly journals Nitrogen Management Based on Visible/Near Infrared Spectroscopy in Pear Orchards

2021 ◽  
Vol 13 (5) ◽  
pp. 927
Author(s):  
Jie Wang ◽  
Xiaojun Shi ◽  
Yangchun Xu ◽  
Caixia Dong
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Fertilizer Application ◽  
First Year ◽  
N Application ◽  
N Concentration ◽  
Application Rates ◽  
Leaf N Concentration ◽  
Leaf N

The timely estimation of nitrogen (N) requirements is essential for managing N fertilizer application in pear orchards. Visible/near infrared spectroscopy is a non-destructive and effective technique for real-time assessment of leaf N concentration, but its utility for decisions about fertilizer application in the pear orchards remains to be determined. In this study, we used leaf spectroscopy to determine leaf N concentration, used this value to calculate the amounts of N required for supplementary fertilization, and then evaluated the effects of the application. Over the two-year study, Cuiguan pear trees were treated with N at the following rates: 0 (N0), 100 (N1), 200 (N2), 300 (N3), and 400 (N4) g N per tree, regarded as five “controlled” N application rates. Another four “regulatory” treatments (Nr1-4) were fertilized as the “controlled” N application rates the first year, then given adjusted N application by topdressing as calculated using the N concentrations inferred from visible/near infrared spectroscopy data the second year. A model (R2 = 0.82) was established the first year to relate leaf spectra and N concentration using a partial least squares regression with full bands (350–2500 nm). The amount of N in the topdressing for the supplemental treatments was determined using the predicted leaf N concentration and the topdressing calculation method adapted from the N balance formula. Results showed that adjusted N applications of the Nr1 and Nr2 increased yield by 26% and 23%, respectively, over the controlled treatments N1 and N2. Although treatments Nr3 and Nr4 did not increase yield significantly over N3 and N4, the partial factor productivity of nitrogen in Nr4 was higher than the N4. The transverse diameter of fruit from Nr1 trees was significantly higher than from N1 trees, while the longitudinal diameter of fruit from Nr1, Nr2, and Nr3 trees was significantly higher than from N1, N2 and N3 trees, suggesting that fruit longitudinal growth and single-fruit weight is stimulated by adjusted N applications. However, the soluble solids in fruit from trees receiving adjusted N were not significantly greater than in fruit from non-supplemented trees. In conclusion, our results illustrate that regulatory N management contributes to fruit yield and quality especially in the nitrogen deficiency condition and improves the nitrogen use efficiency in nitrogen surplus. The N prediction model established using the nondestructive visible/near infrared spectroscopy is convenient and economical.

Effects of rate and timing of nitrogen fertilizer on disease control by fungicides in winter wheat. 1. Grain yield and foliar disease control

2003 ◽  
Vol 140 (1) ◽  
pp. 1-13 ◽  
Author(s):  
J. E. OLESEN ◽  
L. N. JØRGENSEN ◽  
J. PETERSEN ◽  
J. V. MORTENSEN
Keyword(s):  
Powdery Mildew ◽  
Winter Wheat ◽  
Grain Yield ◽  
Disease Control ◽  
Leaf Spot ◽  
Regression Models ◽  
N Fertilizer ◽  
Grain Yields ◽  
Fungicide Application ◽  
Septoria Leaf Spot

The effects of nitrogen (N) rate and timing on need for fungicide application in winter wheat (Triticum aestivum) were investigated in 3 years of field experiments on loamy sand soils in Denmark. A two-factor completely randomized experimental design was used, comprising seven combinations of different N fertilizer rates and application times, and five doses of fungicide (co-formulation propiconazole and fenpropimorph). Two different varieties of winter wheat with high susceptibility to powdery mildew (Blumeria graminis) were used, Florida in the first season and Pepital in the last two seasons. The severity of powdery mildew and septoria leaf spot (mainly Septoria tritici) varied between seasons from slight to moderate with powdery mildew dominating in the first season and septoria leaf spot in the last season. The severity of both powdery mildew and septoria leaf spot assessed as the Area Under the Disease Progress Curve (AUDPC) was increased by application of N in all years, and more so by early applied N. Grain yields increased with increasing N rate and fungicide dose. However, the observed grain yields did not reveal any N×fungicide interactions. Regression models were therefore fitted, relating grain yield to rate and timing of N fertilizer and to AUDPC of powdery mildew and septoria leaf spot, and relating AUDPC to rate and timing of N fertilizer and to fungicide dose. They demonstrated that septoria leaf spot had a considerably higher impact on grain yield than mildew. The optimal fungicide dose and N rate were defined as those giving the highest economic return. The regression models were used to estimate the effect of N rate and timing on optimal fungicide dose, and the effect of fungicide application on optimal N rate. The optimal fungicide dose increased almost linearly with N rate above a minimum N rate, but with a large dependency on price relations. Early applied N caused a higher demand for disease control. The fungicide applications in the model were mainly driven by the need to control septoria leaf spot, whereas powdery mildew gave a poor net return for control. The estimated optimal N fertilizer rate for untreated diseased crops was 60 kg N/ha lower than for crops without disease. The use of fungicides with an efficacy twice that of the EBI-fungicides used in this experiment would increase the optimal N rate by c. 20 kg N/ha.

RESISTANCE TO MILDEW OF SELECTION FAMILY OF RED CURRANT THE BELAYA POTAPENKO × № 1426-21-80

1970 ◽  
pp. 38-40
Author(s):  
O. O. Kalinina ◽  
O. D. Golyaeva ◽  
O. V. Panfilova ◽  
А. V. Pikunova
Keyword(s):  
Powdery Mildew ◽  
Field Resistance ◽  
Disease Development ◽  
Artificial Infection ◽  
Sources Of Resistance ◽  
Climate Conditions ◽  
High Productivity ◽  
Local Soil ◽  
The Family ◽  
Red Currant

Powdery mildew is one of the most harmful fungal diseases that causes economically significant damage to berry plantations. The disease is common in all areas of currant cultivation in the Russian Federation. In this regard, in modern conditions of intensive berry growing, the problem of breeding cultivars that are highly resistant to diseases and pests becomes urgent. Breeders have a difficult task to combine the adaptive potential of the cultivar with its annual high productivity and resistance to biotic environmental factors. When studying the adaptability of introduced cultivars of red currant and selected forms of the Institute to local soil and climate conditions, the following cultivars were identified as sources of economic and useful characteristics and involved in selection: ‘Belaya Potapenko’ as a complex source of resistance powdery mildew and high marketable and taste qualities of berries; SS 1426-21-80 as a source of high productivity and long racemes (raceme length 11-13 cm; up to 20 berries in the raceme). On their base the selection family of red currant has been developed: Belaya Potapenko × ♂SS 1426-21-80. The study of data on the destruction of hybrid seedlings of the selection family by powdery mildew showed that in epiphytotic conditions, the percentage of intensity of the disease development varies over the periods of screening from 0.2% in May to 20.4% in June. Such indicators served as a prerequisite for conducting a comparative test of breeding material in the field under artificial infection with powdery mildew. After artificial infection on the background of epiphytosis, the rate of intensity of the disease development increased slightly and amounted to 35.6% for the family. There were 30 highly resistant seedlings in the family, 10 of which have remained stable and highly resistant since 2018. In these plants we can assume the presence of the so-called field resistance, controlled by polygens, each of which does not give a visible effect of stability, but with different combinations determines one or another of its degree. Highly resistant seedlings will be used in further breeding studies to identify new sources of resistance to powdery mildew.

scholarly journals Combining Process Modelling and LAI Observations to Diagnose Winter Wheat Nitrogen Status and Forecast Yield

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 314
Author(s):  
Andrew Revill ◽  
Vasileios Myrgiotis ◽  
Anna Florence ◽  
Stephen Hoad ◽  
Robert Rees ◽  
...  
Keyword(s):  
Field Experiments ◽  
Process Models ◽  
Agricultural Technologies ◽  
N Application ◽  
Area Index ◽  
Complex Process ◽  
C Cycle ◽  
The Mean ◽  
Leaf N Content ◽  
Leaf N

Climate, nitrogen (N) and leaf area index (LAI) are key determinants of crop yield. N additions can enhance yield but must be managed efficiently to reduce pollution. Complex process models estimate N status by simulating soil-crop N interactions, but such models require extensive inputs that are seldom available. Through model-data fusion (MDF), we combine climate and LAI time-series with an intermediate-complexity model to infer leaf N and yield. The DALEC-Crop model was calibrated for wheat leaf N and yields across field experiments covering N applications ranging from 0 to 200 kg N ha−1 in Scotland, UK. Requiring daily meteorological inputs, this model simulates crop C cycle responses to LAI, N and climate. The model, which includes a leaf N-dilution function, was calibrated across N treatments based on LAI observations, and tested at validation plots. We showed that a single parameterization varying only in leaf N could simulate LAI development and yield across all treatments—the mean normalized root-mean-square-error (NRMSE) for yield was 10%. Leaf N was accurately retrieved by the model (NRMSE = 6%). Yield could also be reasonably estimated (NRMSE = 14%) if LAI data are available for assimilation during periods of typical N application (April and May). Our MDF approach generated robust leaf N content estimates and timely yield predictions that could complement existing agricultural technologies. Moreover, EO-derived LAI products at high spatial and temporal resolutions provides a means to apply our approach regionally. Testing yield predictions from this approach over agricultural fields is a critical next step to determine broader utility.

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