Fertilization Rate and Growth of `Hamlin' Orange Trees Related to Preplant Leaf Nitrogen Levels in the Nursery

Our objectives were to determine the effects of leaf N concentration in citrus nursery trees on subsequent growth responses to fertilization for the first 2 years after planting and the impact of N fertilizer rate on soil NO3-N concentration. `Hamlin' orange [Citrus sinensis (L.) Osb.] trees on `Swingle' citrumelo rootstock [C. paradisi Macf. × P. trifoliata (L.) Raf.] were purchased from commercial nurseries in Apr. 1992 (Expt. 1) and Jan. 1993 (Expt. 2) and were grown in the greenhouse at differing N rates. Five months later, trees for each experiment were separated into three groups (low, medium, and high) based on leaf N concentration and were planted in the field in Oct. 1992 (Expt. 1) or Apr. 1993 (Expt. 2). Trees were fertilized with granular material (8N-2.6P-6.6K-2Mg-0.2Mn-0.12Cu-0.27Zn-1.78Fe) with N at 0, 0.11, 0.17, 0.23, 0.28, or 0.34 kg/tree per year. Soil NO3-N levels were determined at 0- to 15- and 16- to 30-cm depths for the 0.11-, 0.23-, and 0.34-kg rates over the first two seasons in Expt. 2. Preplant leaf N concentration in the nursery varied from 1.4% (Expt. 1) to 4.1% (Expt. 2) but had no effect on trunk diameter, height, shoot growth and number, or dry weight in year 1 (Expt. 1) or years 1 and 2 (Expt. 2) in the field. Similarly, fertilizer rate in the field had no effect on growth during year 1 in the field. However, trunk diameter increased with increasing N rate in year 2 and reached a maximum with N at 0.17 kg/tree per year but decreased at higher rates. Shoot number during the second growth flush in year 2 was much lower for nonfertilized vs. fertilized trees at all rates, which had similar shoot numbers. Nevertheless, leaf N concentrations increased during the season for trees with initially low levels, even for trees receiving low fertilizer rates. This suggests translocation of N from other organs to leaves. Soil NO3-N levels were highest for the 0.34-kg rate and lowest at the 0.11-kg rate. Within 2 to 3 weeks of fertilizing, NO3-N levels decreased rapidly in the root zone.

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Fertilization Rate and Growth of `Hamlin' Orange Trees Related to Preplant Leaf Nitrogen Levels in the Nursery

HortScience ◽

10.21273/hortsci.31.4.613e ◽

1996 ◽

Vol 31 (4) ◽

pp. 613e-614

Author(s):

Laura Guazzelli ◽

Frederick S. Davies ◽

James J. Ferguson

Keyword(s):

N Fertilizer ◽

Soil Nitrate ◽

Growth Responses ◽

Fertilizer Rate ◽

Trunk Diameter ◽

Nitrate N ◽

N Concentration ◽

Leaf N Concentration ◽

N Fertilizer Rate ◽

Leaf N

Our objectives were to determine if leaf N concentration in citrus nursery trees affected subsequent growth responses to fertilization for the first 2 years after planting and how N fertilizer rate affected soil nitrate-N concentration. `Hamlin' orange [Citrus sinensis (L.) Osb.] trees on `Swingle' citrumelo rootstock [C. paradisi Macf. × P. trifoliata (L.) Raf.] were purchased from commercial nurseries and grown in the greenhouse at differing N rates. Three to five months later trees were separated into three groups (low, medium, high) based on leaf N concentration and planted in the field in Oct. 1992 (Expt. 1) or Apr. 1993 (Expt. 2). Trees were fertilized with granular material (8N–2.6P–6.6K) with N at 0 to 0.34 kg/tree yearly. Soil nitrate-N levels were also determined in Expt. 2. Preplant leaf N concentration in the nursery varied from 1.4% to 4.1% but had no effect on trunk diameter, height, shoot growth, and number or dry weight in year 1 (Expt. 1) or years 1 and 2 (Expt. 2) in the field. Similarly, N fertilizer rate had no effect on growth during year 1 in the field. However, trunk diameter increased with increasing N rate in year 2 and reached a maximum with N at 0.17 kg/tree yearly. Shoot number during the second growth flush in year 2 was much lower for nonfertilized vs. fertilized trees. Leaf N concentrations increased during the season for trees with initially low levels even for trees receiving low fertilizer rates. Soil nitrate-N levels were highest at the 0.34-kg rate, and lowest at the 0.11-kg rate. Nitrate-N levels decreased rapidly in the root zone within 2 to 3 weeks of fertilizing.

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Fertilization and Growth of Field-grown Citrus Nursery Trees in Florida

HortTechnology ◽

10.21273/horttech.18.1.29 ◽

2008 ◽

Vol 18 (1) ◽

pp. 29-33 ◽

Cited By ~ 3

Author(s):

Frederick S. Davies ◽

Glenn Zalman

Keyword(s):

Dry Weight ◽

Fine Sand ◽

N Fertilization ◽

Poncirus Trifoliata ◽

Tree Trunk ◽

Trunk Diameter ◽

N Concentration ◽

Leaf N Concentration ◽

Optimum N Rate ◽

Leaf N

The objective of this study was to determine the effects of various levels of nitrogen (N) on growth of ‘Hamlin’ orange (Citrus sinensis) trees on Carrizo citrange (C. sinensis × Poncirus trifoliata) rootstock in a field nursery. Newly budded liners were obtained from commercial nurseries and received from 0 to 3976 kg N per treated hectare annually (8N–0P–6.6K) in 14 applications per season. Tree trunk diameter, height, and dry weight were measured in two separate experiments. Total dry weight and trunk diameter were greatest for trees receiving 794 kg·ha−1 N annually during both seasons. However, annual N rates more than 1589 kg·ha−1 reduced trunk diameters and dry weight compared with the optimum N rate during both seasons. Leaf N concentration and N rate were positively correlated in both seasons, but leaf N concentration was poorly correlated with tree trunk diameter and dry weight. Therefore, very high rates of N fertilization may actually reduce ‘Hamlin’ orange tree growth in field nurseries when growing in an Arredondo fine sand.

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Potassium Nutrition Affects Leaf Growth, Anatomy, and Macroelements of Guzmania

HortScience ◽

10.21273/hortsci.43.1.146 ◽

2008 ◽

Vol 43 (1) ◽

pp. 146-148 ◽

Cited By ~ 9

Author(s):

Chao-Yi Lin ◽

Der-Ming Yeh

Keyword(s):

Leaf Growth ◽

Dry Weight ◽

Storage Tissue ◽

Potassium Nutrition ◽

Coconut Husk ◽

N Concentration ◽

Leaf N Concentration ◽

K Concentration ◽

Leaf P ◽

Leaf N

Guzmania lingulata (L.) Mez. ‘Cherry’ plants were grown in coconut husk chips. All plants were given 8 mm nitrogen (N), 2 mm phosphorus (P), 4 mm calcium (Ca), and 1 mm magnesium (Mg) at each irrigation with potassium (K) concentration at 0, 2, 4, or 6 mm. After 9 months, K concentration did not alter the number of new leaves, and shoot and root dry weights. Increasing K concentration did not affect the length but increased the width of the most recently fully expanded leaves (the sixth leaves). Plants under 0 K exhibited yellow spots and irregular chlorosis on old leaves being more severe at the middle of the blade and leaf tip. Numbers of leaves with yellow spots or chlorosis decreased with increasing K concentration. Chlorenchyma thickness was unaffected by K concentration, whereas water storage tissue and total leaf thickness increased with increasing K concentration. Leaf N concentration in the sixth or 10th leaf was unaffected by solution K concentration. However, plants at 0 mm K had higher N concentration in the 14th leaf than those in sixth and 10th leaves. Leaf P, Ca, and Mg concentrations decreased with increasing solution K concentration. K concentrations were higher in the sixth leaf than the 14th leaf in plants at 0, 2, or 4 mm K, whereas leaf K concentration was 15 g·kg−1 on dry weight basis in the sixth, 10th, or 14th leaves in plants treated with 6 mm K.

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Optimal Nitrogen Concentration and Rapid Nutritional Diagnosis of Nitrogen Requirement for Container Production of Malabar Chestnut

HortTechnology ◽

10.21273/horttech.25.5.602 ◽

2015 ◽

Vol 25 (5) ◽

pp. 602-607

Author(s):

Yung-Liang Peng ◽

Fang-Yin Liu ◽

Rong-Show Shen ◽

Yu-Sen Chang

Keyword(s):

Plant Growth ◽

Dry Weight ◽

N Fertilization ◽

Chlorophyll Meter ◽

Leaf Chlorophyll ◽

N Concentration ◽

Leaf N Concentration ◽

Leaf Dry Weight ◽

N Requirement ◽

Leaf N

Nitrogen (N) is a major element required for crop cultivation and an important factor affecting plant growth and development. Malabar chestnut (Pachira macrocarpa) is an important ornamental potted plant crop whose N requirement has been studied, and a rapid monitoring method to manage N fertilization during its commercial production is yet to be established. Malabar chestnut seedlings were fertilized weekly with 0, 4, 8, 16, or 24 mm N. After 12 weeks, 16 mm N was found to yield the greatest plant growth such as plant height, number of nodes, and total leaf area. Measurements of chlorophyll meter readings, leaf chlorophyll concentration, leaf N concentration, and leaf dry weight all indicated that the optimal level of N fertilization was 16 mm N. A chlorophyll meter can be used to monitor nondestructively whether sufficient N has been supplied to support optimal plant growth. In this study, a chlorophyll meter reading of 46.1 corresponded with a critical leaf N concentration of 2.65%, defined as the leaf N concentration when the leaf dry weight was at 90% of saturation point. Additional N supplied beyond this critical level increased foliar chlorophyll content and improved the rate of net photosynthesis. Therefore, chlorophyll meter readings, which are convenient and nondestructive can serve as a reliable reference for commercial production in monitoring N requirement for optimum growth of malabar chestnut. Weekly fertilization of malabar chestnut with 16 mm N and maintaining leaf chlorophyll meter readings between 46.1 and 58.4 are recommended.

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Nitrogen use efficiency and critical leaf N concentration of Aloe vera in urea and diammonium phosphate amended soil

Heliyon ◽

10.1016/j.heliyon.2020.e05718 ◽

2020 ◽

Vol 6 (12) ◽

pp. e05718

Author(s):

Md. Akhter Hossain Chowdhury ◽

Taslima Sultana ◽

Md. Arifur Rahman ◽

Tanzin Chowdhury ◽

Christian Ebere Enyoh ◽

...

Keyword(s):

Nitrogen Use Efficiency ◽

Aloe Vera ◽

Diammonium Phosphate ◽

Nitrogen Use ◽

N Concentration ◽

Leaf N Concentration ◽

Use Efficiency ◽

Leaf N ◽

Amended Soil

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Optical sensing estimation of leaf nitrogen concentration in maize across a range of water-stress levels

Crop and Pasture Science ◽

10.1071/cp10374 ◽

2011 ◽

Vol 62 (6) ◽

pp. 474 ◽

Cited By ~ 9

Author(s):

Tong-Chao Wang ◽

B. L. Ma ◽

You-Cai Xiong ◽

M. Farrukh Saleem ◽

Feng-Min Li

Keyword(s):

Water Stress ◽

Vegetation Index ◽

Optical Sensing ◽

Leaf Nitrogen ◽

Growth Stages ◽

N Concentration ◽

Leaf N Concentration ◽

Chlorophyll Index ◽

Plant Moisture ◽

Leaf N

Optical sensing techniques offer an instant estimation of leaf nitrogen (N) concentration during the crop growing season. Differences in plant-moisture status, however, can obscure the detection of differences in N levels. This study presents a vegetation index that robustly measures differences in foliar N levels across a range of plant moisture levels. A controlled glasshouse study with maize (Zea mays L.) subjected to both water and N regimes was conducted in Ottawa, Canada. The purpose of the study was to identify spectral waveband(s), or indices derived from different wavebands, such as the normalised difference vegetation index (NDVI), that are capable of detecting variations in leaf N concentration in response to different water and N stresses. The experimental design includes three N rates and three water regimes in a factorial arrangement. Leaf chlorophyll content and spectral reflectance (400–1075 nm) were measured on the uppermost fully expanded leaves at the V6, V9 and V12 growth stages (6th, 9th and 12th leaves fully expanded). N concentrations of the same leaves were determined using destructive sampling. A quantitative relationship between leaf N concentration and the normalised chlorophyll index (normalised to well fertilised and well irrigated plants) was established. Leaf N concentration was also a linear function (R2 = 0.9, P < 0.01) of reflectance index (NDVI550, 760) at the V9 and V12 growth stages. Chlorophyll index increased with N nutrition, but decreased with water stress. Leaf reflectance at wavebands of 550 ± 5 nm and 760 ± 5 nm were able to separate water- and N-stressed plants from normal growing plants with sufficient water and N supply. Our results suggest that NDVI550, 760 and normalised chlorophyll index hold promise for the assessment of leaf N concentration at the leaf level of both normal and water-stressed maize plants.

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Biological Control of the Weedy Plant (Rumex crispus) at the Seedling Growth Stage by the Green Dock Beetle (Gastrophysa viridula)

Journal of King Abdulaziz University-Meteorology Environment and Arid Land Agriculture Sciences ◽

10.4197/met.28-1.3 ◽

2019 ◽

Vol 28 (1) ◽

pp. 21-31

Author(s):

Khalid S. Alshallash Khalid S. Alshallash

Keyword(s):

Biological Control ◽

Seedling Growth ◽

Growth Stage ◽

Biological Control Agent ◽

Dry Weight ◽

Control Agent ◽

Growth Stages ◽

Rumex Crispus ◽

Shoot Number ◽

The Impact

In four glasshouse experiments, the effectiveness of the adult green dock beetle Gastrophysa viridula (Coleoptera: Chrysomelidae), at the effective number of applied individuals, for use as a biological control agent of curled dock, Rumex crispus (Polygonaceae) were studied. The feeding of the beetle was investigated at four different numbers of beetle (0, 1, 2, 3) and at four seedling growth stages of the plant, defined by the average of leaf area per plant (1-1.22 , 2-4.45, 3-11.56, and 4-71.52 cm2/plant). Grazing by one, two or three dock beetles did not result in a significant reduction in dock dry weight or shoot numbers at the youngest growth stage. However, both at later seedling growth stages were significantly affected (P ? 0.0001), at any beetles number. The increase of beetle numbers caused nonsignificant increased effect, in some trials, confirming the impact of a single beetle. Three months after beetle grazing, dock seedlings of first, second and third growth stages were not able to regrow, however, some plants at the 4th growth stage, re-emerged. This suggested that the highest effect of beetle's feeding occurs on the early seedling stages. Statistical analysis showed a positive correlation (0.77) between dry weight and shoot number at all the four seedling growth stages, thus confirming the impact of the beetle on both the dry weight and shoot numbers. Combining beetle grazing with other control methods at older dock seedling stages could, therefore, provide better suppression

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

Remote Sensing ◽

10.3390/rs12071139 ◽

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.

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Rootstock influences postharvest anthracnose development in 'Hass' avocado

Australian Journal of Agricultural Research ◽

10.1071/ar01015 ◽

2001 ◽

Vol 52 (10) ◽

pp. 1017 ◽

Cited By ~ 22

Author(s):

S. L. Willingham ◽

K. G. Pegg ◽

A. W. Cooke ◽

L. M. Coates ◽

P. W. B. Langdon ◽

...

Keyword(s):

First Record ◽

Mineral Nutrients ◽

Fruit Flesh ◽

N Concentration ◽

Nursery Stock ◽

Leaf N Concentration ◽

Hass Avocado ◽

Mn Concentration ◽

Leaf N

Rootstock studies conducted on ‘Hass’ avocado found that rootstock had a significant impact on postharvest anthracnose susceptibility. This is the first record of such an effect for avocado. The severity and incidence of anthracnose was significantly lower on ‘Hass’ grafted to ‘Velvick’ Guatemalan seedling rootstock compared with the ‘Duke 6’ Mexican seedling rootstock. Differences in anthracnose susceptibility were related to significant differences in concentrations of antifungal dienes in the leaves and mineral nutrients in the leaves and fruits from trees grafted to different rootstocks. Leaf diene concentrations were up to 1.5 times higher in ‘Hass’ trees on the ‘Velvick’ than the ‘Duke 6’ rootstock. In ungrafted nursery stock trees, diene concentrations were around 3 times higher in ‘Velvick’ than ‘Duke 6’ leaves. The ‘Velvick’/‘Hass’ combination also had a significantly lower leaf N concentration, a significantly higher fruit flesh Mn concentration, and significantly lower and higher leaf N/Ca and Ca+Mg/K ratios, respectively. A significant correlation (r = 0.82) between anthracnose severity and skin N/Ca ratio was also evident.

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