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

HortScience ◽  
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.

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

1996 ◽  
Vol 6 (4) ◽  
pp. 383-387 ◽  
Author(s):  
Laura Guazzelli ◽  
Frederick S. Davies ◽  
James J. Ferguson
Keyword(s):  
Root Zone ◽  
Dry Weight ◽  
Growth Responses ◽  
Fertilizer Rate ◽  
Trunk Diameter ◽  
N Concentration ◽  
Shoot Number ◽  
Leaf N Concentration ◽  
The Impact ◽  
Leaf N

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.

Diagnostic nitrogen concentrations for tomatoes grown in sand culture

1988 ◽  
Vol 28 (3) ◽  
pp. 401 ◽  
Author(s):  
DO Huett ◽  
G Rose
Keyword(s):  
Critical Values ◽  
Sand Culture ◽  
Nutrient Concentrations ◽  
Total N ◽  
Nitrate N ◽  
N Concentration ◽  
Leaf N Concentration ◽  
Petiole Sap ◽  
N Status ◽  
Leaf N

The tomato cv. Flora-Dade was grown in sand culture with 4 nitrogen (N) levels of 1.07-32.14 mmol L-1 applied as nitrate each day in a complete nutrient solution. The youngest fully opened leaf (YFOL) and remaining (bulked) leaves were harvested at regular intervals over the 16-week growth period. Standard laboratory leaf total and nitrate N determinations were conducted in addition to rapid nitrate determinations on YFOL petiole sap. The relationships between plant growth and leaf N concentration, which were significantly affected by N application level, were used to derive diagnostic leaf N concentrations. Critical and adequate concentrations in petiole sap of nitrate-N, leaf nitrate-N and total N for the YFOL and bulked leaf N were determined from the relationship between growth rate relative to maximum at each sampling time and leaf N concentration. YFOL petiole sap nitrate-N concentration, which can be measured rapidly in the field by using commercial test strips, gave the most sensitive guide to plant N status. Critical values of 770-1 120 mg L-I were determined over the 10-week period after transplanting (first mature fruit). YFOL (leaf + petiole) total N concentration was the most consistent indicator of plant N status where critical values of4.45-4.90% were recorded over the 4- 12 week period after transplanting (early harvests at 12 weeks). This test was less sensitive but more precise than the petiole sap nitrate test. The concentrations of N, potassium, phosphorus, calcium and magnesium in YFOL and bulked leaf corresponding to the N treatments producing maximum growth rates are presented, because nutrient supply was close to optimum and the leaf nutrient concentrations can be considered as adequate levels.

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.

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

2008 ◽  
Vol 18 (1) ◽  
pp. 29-33 ◽  
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.

Yield response of forage grasses to N fertilizer as related to spring soil nitrate sorbed on anionic exchange membranes

2000 ◽  
Vol 80 (1) ◽  
pp. 203-212 ◽  
Author(s):  
N. Ziadi ◽  
R. R. Simard ◽  
G. Allard ◽  
G. Parent
Keyword(s):  
N Uptake ◽  
N Fertilizer ◽  
Forage Yield ◽  
Yield Response ◽  
Soil Nitrate ◽  
Forage Grasses ◽  
Fertilizer N ◽  
Fertilizer Rate ◽  
Anionic Exchange ◽  
N Fertilizer Rate

Soil N availability is an important factor in forage grass production. Maximising N fertilizer efficiency is essential to improve profitability and to reduce the environmental risk associated with residual excess soil N. The objectives of this study were (i): to determine the effects of N fertilizer on yield, N uptake and NO3–N concentration of forage grasses produced in Western Quebec; and (ii) to compare spring soil NO3−measured by anionic exchange membranes (NO3AEMs) and by water extraction (NO3w) as a criterion to predict fertilizer N requirements of forage grasses. The yield response of grasses, especially timothy (Phleum pratense L.), to different rates of NH4NO3 (0 to 240 kg N ha−1) on heavy clay soils (Humic Gleysols) was studied from 1994 to 1996 at four sites in the Abitibi-Temiscamingue area, Quebec (Canada). Nitrogen significantly (P < 0.001) increased forage yield, N uptake, and NO3–N concentration. The economically optimum N fertilizer rate (Nop) for forage yield varied from 25 to 240 kg N ha−1 depending on sites and years, and averaged 125 kg N ha−1. The Nop can be predicted more adequately by NO3AEMs (R2 = 0.45) than by NO3w (R2 = 0.09). Based only on the relationship between the relative yield and spring soil nitrate, NO3AEMs could be used as a criterion for fertilizer N recommendation of forage grasses in this cool continental climate. Key words: N fertilizer, nitrate, grass, economically optimum N fertilizer rate

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

Heliyon ◽  
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

scholarly journals Corralling, planting density, and N fertilizer rate effect on soil properties, weed diversity, and maize yield

2018 ◽  
Vol 43 (3) ◽  
pp. 243-260
Author(s):  
Nurudeen Abdul Rahman ◽  
Asamoah Larbi ◽  
Andrews Opoku ◽  
Francis Marthy Tetteh ◽  
Irmgard Hoeschle-Zeledon
Keyword(s):  
Soil Properties ◽  
Maize Yield ◽  
Rate Effect ◽  
N Fertilizer ◽  
Planting Density ◽  
Fertilizer Rate ◽  
Weed Diversity ◽  
N Fertilizer Rate

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

2011 ◽  
Vol 62 (6) ◽  
pp. 474 ◽  
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.

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.

An integrative influence of saline water irrigation and fertilization on the structure of soil bacterial communities

2019 ◽  
Vol 157 (9-10) ◽  
pp. 693-700
Author(s):  
L. J. Chen ◽  
C. S. Li ◽  
Q. Feng ◽  
Y. P. Wei ◽  
Y. Zhao ◽  
...  
Keyword(s):  
Irrigation Water ◽  
Saline Water ◽  
N Fertilizer ◽  
Water Salinity ◽  
Fertilizer Rate ◽  
Irrigation Amount ◽  
Soil Microbial ◽  
Irrigation Water Salinity ◽  
Soil Bacterial ◽  
N Fertilizer Rate

AbstractAlthough numerous studies have investigated the individual effects of salinity, irrigation and fertilization on soil microbial communities, relatively less attention has been paid to their combined influences, especially using molecular techniques. Based on the field of orthogonal designed test and deoxyribonucleic acid sequencing technology, the effects of saline water irrigation amount, salinity level of irrigation water and nitrogen (N) fertilizer rate on soil bacterial community structure were investigated. The results showed that the irrigation amount was the most dominant factor in determining the bacterial richness and diversity, followed by the irrigation water salinity and N fertilizer rate. The values of Chao1 estimator, abundance-based coverage estimator and Shannon indices decreased with an increase in irrigation amount while increased and then decreased with an increase in irrigation water salinity and N fertilizer rate. The highest soil bacterial richness and diversity were obtained under the least irrigation amount (25 mm), medium irrigation water salinity (4.75 dS/m) and medium N fertilizer rate (350 kg/ha). However, different bacterial phyla were found to respond distinctively to these three factors: irrigation amount significantly affected the relative abundances of Proteobacteria and Chloroflexi; irrigation water salinity mostly affected the members of Actinobacteria, Gemmatimonadetes and Acidobacteria; and N fertilizer rate mainly influenced the Bacteroidetes' abundance. The results presented here revealed that the assessment of soil microbial processes under combined irrigation and fertilization treatments needed to be more careful as more variable consequences would be established by comparing with the influences based on an individual factor, such as irrigation amount or N fertilizer rate.

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