Indirect Estimations of Lentil Leaf and Plant N by SPAD Chlorophyll Meter

A Soil Plant Analysis Development (SPAD) chlorophyll meter can be used to screen for leaf nitrogen (N) concentration in breeding programs. Lentil (Lens culinarisL.) cultivars were grown under varied N regimes, SPAD chlorophyll meter readings (SCMR) were recorded from the cultivars leaves, and leaf N concentration was measured by combustion. Linear regression and the nonlinear Radial Basis Functions (RBF) neural networks models were employed to estimate leaf N concentration (LNC) based on the SCMR values. The closest estimates of LNC were obtained from the multivariate models in which the combination of plant age, leaf thickness, and SCMR was employed as the independent variable. In comparison, SCMR as the single independent variable in both models estimated less than 50% of LNC variations. The results showed significant effects of soil moisture and plant age on the association of LNC –SCMR as well as the relationship of LNC with plant N, grain yield, and days to maturity. However, the effect of cultivar on the measured variables was negligible. Although lentil N can be diagnosed by comparing SCMR values of the crop with those from a well-fertilized (N fixing) plot, the results did not support using SPAD chlorophyll meter for screening lentil LNC.

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Quantifying the nonlinearity in chlorophyll meter response to corn leaf nitrogen concentration

Canadian Journal of Plant Science ◽

10.4141/cjps95-030 ◽

1995 ◽

Vol 75 (1) ◽

pp. 179-182 ◽

Cited By ~ 81

Author(s):

L. M. Dwyer ◽

D. W. Stewart ◽

E. Gregorich ◽

A. M. Anderson ◽

B. L. Ma ◽

...

Keyword(s):

Growth Stage ◽

Nitrogen Concentration ◽

Leaf Nitrogen ◽

Growth Stages ◽

Concentration Data ◽

Chlorophyll Meter ◽

N Concentration ◽

Leaf N Concentration ◽

Non Destructive ◽

Leaf N

Chlorophyll meters have been used to provide a rapid non-destructive method to estimate corn leaf nitrogen (N) concentration, although meter readings plateau at high leaf N levels. Paired chlorophyll meter and leaf N concentration data were obtained for ear level leaves at growth stages ranging from 3 wk before anthesis to 5 wk after anthesis over a 2-yr period at Ottawa, Ontario. Separate quadratic-plus-plateau models best represented chlorophyll meter response to leaf N concentration for pre-anthesis, early grain-fill and late grain-fill stages; chlorophyll meter readings corresponding to the beginning of the plateau increased at later growth stages. Leaf N concentration was estimated well from chlorophyll meter readings up to the plateau range using growth stage specific functions (R2 ≥ 0.77) but chlorophyll meter readings beyond the plateau should not be used to estimate leaf N concentration. Key words: Chlorophyll meter calibration, maize

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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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Effect of spad techniques and planting density on 'Y' leaf nitrogen concentration in transplanted rice

Acta Agronomica Hungarica ◽

10.1556/aagr.52.2004.1.11 ◽

2004 ◽

Vol 52 (1) ◽

pp. 95-104 ◽

Cited By ~ 1

Author(s):

P. Janaki ◽

T. M. Thiyagarajan

Keyword(s):

Grain Yield ◽

Field Experiments ◽

Nitrogen Concentration ◽

Planting Density ◽

Growth Stages ◽

Chlorophyll Meter ◽

N Concentration ◽

Leaf N Concentration ◽

N Management ◽

Leaf N

Field experiments were conducted in June-September 1998 and 1999 with rice variety ASD18 at the wetland farm of Tamil Nadu Agricultural University, in Coimbatore, India to examine variations in 'Y' leaf (youngest fully expanded leaf) N concentration as influenced by different planting densities and N management strategies in a split plot design. The main plot consisted of three plant populations (33, 66 and 100 hills m-2) and the sub-plots treatments of five N management approaches. The results revealed that the nitrogen concentration progressively declined with growth, the decline being steep up to 35 days after transplanting, wereafter the values became almost linear up to the flowering stage in all the treatments. The mean 'Y' leaf N was found to be significantly higher at 33 hills m-2 (45.1 g kg-1), while the other two densities were on par (42.9 g kg-1). When N application was based on chlorophyll meter (SPAD) values the leaf N concentration was maintained at a level of 39.2 to 51.9 g kg-1 to produce maximum grain yield. A significant correlation was observed between the chlorophyll meter values and 'Y' leaf N concentrations at various days after transplanting (r values ranged from 0.57* to 0.83**), while the correlation was highly significant during the major physiological growth stages. Though the 'Y' leaf content was significantly higher in the treatment involving Sesbania rostrata green manuring + 150 kg N applied in splits, the grain yield produced was on par in all the N applied treatments. A highly significant correlation was observed between the grain yield and both 'Y' leaf N content and SPAD values during various growth periods.

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Altitudinal effects on leaf traits and shoot growth of Betulaplatyphylla var. japonica

Canadian Journal of Forest Research ◽

10.1139/x95-203 ◽

1995 ◽

Vol 25 (11) ◽

pp. 1881-1885 ◽

Cited By ~ 11

Author(s):

Gaku Kudo

Keyword(s):

Shoot Growth ◽

Leaf Size ◽

Leaf Traits ◽

Growing Season ◽

Leaf Nitrogen ◽

Leaf Life Span ◽

N Concentration ◽

Leaf N Concentration ◽

Lower Site ◽

Leaf N

Leaf demography, shoot growth, and seasonal changes of leaf size, specific leaf area, and leaf nitrogen (N) concentration of Betulaplatyphylla var. japonica Hara were compared at two altitudes (140 and 700 m above sea level). At the higher site, where the length of growing season was restricted, leaf life-span was shorter and leaf N concentration was higher throughout the growing season than at the lower site. Leaf size did not differ between sites. Production of short-lived and high N concentration leaves was considered adaptive under the condition of short growing season. At the higher site, N was translocated from senescing early leaves to late leaves in mid-September, whereas a significant increase in late leaf N concentration was not observed at the lower site. There were no differences in shoot growth, bud size, late leaf number on long shoots between sites, probably because of effective N use at the higher site.

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Down-Regulation of Photosynthesis to Elevated CO2 and N Fertilization in Understory Fraxinus rhynchophylla Seedlings

Forests ◽

10.3390/f12091197 ◽

2021 ◽

Vol 12 (9) ◽

pp. 1197

Author(s):

Siyeon Byeon ◽

Kunhyo Kim ◽

Jeonghyun Hong ◽

Seohyun Kim ◽

Sukyung Kim ◽

...

Keyword(s):

Elevated Co2 ◽

N Fertilization ◽

Leaf Nitrogen ◽

N Availability ◽

Down Regulation ◽

Leaf Production ◽

N Concentration ◽

Leaf N Concentration ◽

Regulation Of Photosynthesis ◽

Leaf N

(1) Background: Down-regulation of photosynthesis has been commonly reported in elevated CO2 (eCO2) experiments and is accompanied by a reduction of leaf nitrogen (N) concentration. Decreased N concentrations in plant tissues under eCO2 can be attributed to an increase in nonstructural carbohydrate (NSC) and are possibly related to N availability. (2) Methods: To examine whether the reduction of leaf N concentration under eCO2 is related to N availability, we investigated understory Fraxinus rhynchophylla seedlings grown under three different CO2 conditions (ambient, 400 ppm [aCO2]; ambient × 1.4, 560 ppm [eCO21.4]; and ambient × 1.8, 720 ppm [eCO21.8]) and three different N concentrations for 2 years. (3) Results: Leaf and stem biomass did not change under eCO2 conditions, whereas leaf production and stem and branch biomass were increased by N fertilization. Unlike biomass, the light-saturated photosynthetic rate and photosynthetic N-use efficiency (PNUE) increased under eCO2 conditions. However, leaf N, Rubisco, and chlorophyll decreased under eCO2 conditions in both N-fertilized and unfertilized treatments. Contrary to the previous studies, leaf NSC decreased under eCO2 conditions. Unlike leaf N concentration, N concentration of the stem under eCO2 conditions was higher than that under ambient CO2 (4). Conclusions: Leaf N concentration was not reduced by NSC under eCO2 conditions in the understory, and unlike other organs, leaf N concentration might be reduced due to increased PNUE.

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Leaf Nitrogen Status on Yield and Quality of Roses

HortScience ◽

10.21273/hortsci.35.4.564c ◽

2000 ◽

Vol 35 (4) ◽

pp. 564C-564b

Author(s):

Raul I. Cabrera

Keyword(s):

Experimental Period ◽

Leaf Nitrogen ◽

Stem Length ◽

Yield And Quality ◽

Leaf Chlorophyll ◽

N Concentration ◽

Biomass Yields ◽

Leaf N Concentration ◽

Plant Yields ◽

Leaf N

The establishment of critical tissue N levels for greenhouse rose production has been primarily based on visual symptoms of N deficiency, with relatively less consideration to yield parameters. This work examined the relationship between rose leaf N concentration and flower yield and quality. Container-grown `Royalty' rose plants were irrigated for 13 months with complete nutrient solutions containing N concentrations of 30, 60, 90, 120, 150 and 220 mg·L–1. Optimum flower and dry biomass yields, stem length, and stem weights were obtained in plants irrigated with 90 mg·L–1 N. Leaf N concentrations increased asymptotically with N applications, stabilizing at N concentrations >90 mg·L–1. Time of the year had an effect on overall leaf N concentrations, with higher values observed in the winter, and lower values in the summer. Leaf N concentrations were linearly, and significantly, correlated with leaf chlorophyll content and leaf color attributes (hue, chroma, and value). Quadratic relationships between leaf N concentration and rose plant yields were observed only for the second half of the experimental period, and depicted an apparent, and striking, plant control over tissue N status. In addition, these relationships indicated that optimum plant yields were possible during spring and summer with leaf N concentrations below the recommended critical level of 3% (as low as 2.4% to 2.5%). These results suggest that leaf N concentration per se is not a dependable indicator of rose productivity.

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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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The Relationship between Reputation, Customer Satisfaction, Trust, and Loyalty

Journal of Public Administration and Governance ◽

10.5296/jpag.v4i3.6678 ◽

2014 ◽

Vol 4 (3) ◽

pp. 368 ◽

Cited By ~ 10

Author(s):

Roshana Gul

Keyword(s):

Customer Satisfaction ◽

Customer Loyalty ◽

Significant Relationship ◽

Positive Sign ◽

Medical College ◽

Independent Variable ◽

Relationship Of ◽

The Relationship ◽

Self Administered Questionnaire

Though a lot of studies have been done to conclude customer loyalty as dependent variable but still there is a vast margin of researches to be conducted in future in different spheres of this construct. On the other hand the truth of the importance of customer loyalty as an enduring asset cannot be falsified. It is fundamental for organizations to build up long term and mutual beneficial associations with the customers. The purpose of this research paper is to show the inter relationship of reputation, customer satisfaction and trust on customer loyalty. According to the observations reputation is the major independent variable that has significant relationship with customer satisfaction, customer loyalty, and trust. Data for this research study was taken from the Islamia University, Quaid-e-Azam Medical College, and different banks located at various geographic locations of Bahawalpur region of Pakistan. Data was collected through self administered questionnaire and analyzed by using regression through SPSS. The results have been drawn from 150 users of NISHAT LINEN and it was found that there is positive and significant relationship among reputation, customer satisfaction, trust and customer loyalty. Hence the studies give the positive sign that with the increment of reputation, customer satisfaction and trust the customer loyalty enhances.

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HUBUNGAN GAYA KEPEMIMPINAN TERHADAP PRODUKTIVITAS KERJA KARYAWAN BAGIAN LIQUID PT ITRASAL YANG DIMEDIASI OLEH MOTIVASI KERJA

JIFFK : Jurnal Ilmu Farmasi dan Farmasi Klinik ◽

10.31942/jiffk.v15i01.2173 ◽

2018 ◽

Vol 15 (01) ◽

pp. 51

Author(s):

Endang Rachmawati

Keyword(s):

Leadership Style ◽

Positive Relationship ◽

Work Motivation ◽

Primary Data ◽

Linear Regression Method ◽

Employee Productivity ◽

Independent Variable ◽

R Value ◽

Relationship Of ◽

The Relationship

INTISARI Penelitian ini bertujuan untuk mengidentifikasi hubungan Gaya Kepemimpinan terhadap Produktivitas Karyawan PT. ITRASAL yang dimediasi oleh Motivasi Kerja. Penelitian ini menggunakan rancangan penelitian metode asosiatif dengan jenis penelitian survey yang akan mengungkapkan hubungan dua variabel, yaitu Gaya Kepemimpinan sebagai variabel bebas dan Produktivitas sebagai variabel terikat. Data primer berasal dari kuesioner yang disebarkan kepada karyawan bagian Liquid Departemen Produksi PT ITRASAL, dan hasil diskusi dengan karyawan bagian tersebut. Selanjutnya data yang diperoleh dianalisis menggunakan metode korelasi dan regresi linear. Dari penelitian ini diperoleh hasil bahwa nilai r untuk variabel Gaya Kepemimpinan terhadap Produktivitas adalah 0,557 dan nilai t adalah 8.951. Nilai r untuk variabel Gaya Kepemimpinan terhadap Motivasi adalah 0,278 dan nilai t adalah 5,022. Terdapat hubungan positif antara Gaya Kepemimpinan terhadap Produktivitas dan Gaya Kepemimpinan berpengaruh positif terhadap Motivasi. Nilai r untuk variabel Motivasi terhadap Produktivitas adalah 0,377 dan nilai t adalah 6,251. Terdapat hubungan positif antara Motivasi terhadap Produktivitas. Kata kunci : Gaya kepemimpinan, Motivasi kerja, Produktivitas karyawan ABSTRACT This study aims to identify the relationship of leadership style to employee productivity PT. ITRASAL is mediated by work motivation. This research uses the research design of associative method with the type of survey research that will reveal the relationship of two variables, namely Leadership Style as independent variable and productivity as dependent variable. Primary data comes from a questionnaire distributed to employees of the Liquid Department of Production Department of PT ITRASAL, and the results of discussions with employees of that section. Further data obtained were analyzed using correlation and linear regression method. From this research, the result that r value for leadership style variable to productivity is 0,557 and t value is 8,951. The r value for the leadership style variable for motivation is 0.278 and the t value is 5.022. There is a positive relationship between leadership style on productivity and leadership style have a positive effect on motivation. The r value for the Motivation variable on productivity is 0.377 and the t value is 6.251. There is a positive relationship between motivation to productivity. Keywords: Leadership style, Motivation work, Employee productivity

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