The Use of Chlorophyll Meters to Assess Crop N Status and Derivation of Sufficiency Values for Sweet Pepper

Chlorophyll meters are promising tools for improving the nitrogen (N) management of vegetable crops. To facilitate on-farm use of these meters, sufficiency values that identify deficient and sufficient crop N status are required. This work evaluated the ability of three chlorophyll meters (SPAD-502, atLEAF+, and MC-100) to assess crop N status in sweet pepper. It also determined sufficiency values for optimal N nutrition for each meter for pepper. The experimental work was conducted in a greenhouse, in Almería, Spain, very similar to those used for commercial production, in three different crops grown with fertigation. In each crop, there were five treatments of different N concentration in the nutrient solution, applied in each irrigation, ranging from a very deficient to very excessive N supply. In general, chlorophyll meter measurements were strongly related to crop N status in all phenological stages of the three crops, indicating that these measurements are good indicators of the crop N status of pepper. Sufficiency values determined for each meter for the four major phenological stages were consistent between the three crops. This demonstrated the potential for using these meters with sufficiency values to improve the N management of commercial sweet pepper crops.

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Assessing Performance of Vegetation Indices to Estimate Nitrogen Nutrition Index in Pepper

Remote Sensing ◽

10.3390/rs12050763 ◽

2020 ◽

Vol 12 (5) ◽

pp. 763 ◽

Cited By ~ 1

Author(s):

Romina de Souza ◽

M. Teresa Peña-Fleitas ◽

Rodney B. Thompson ◽

Marisa Gallardo ◽

Francisco M. Padilla

Keyword(s):

Nitrogen Nutrition ◽

Linear Regression Analysis ◽

Vegetation Indices ◽

Sweet Pepper ◽

Fruit Growth ◽

Green Band ◽

Phenological Stages ◽

Nitrogen Nutrition Index ◽

N Management ◽

N Status

Vegetation indices (VIs) can be useful tools to evaluate crop nitrogen (N) status. To be effective, VIs measurements must be related to crop N status. The nitrogen nutrition index (NNI) is a widely accepted parameter of crop N status. The present work evaluates the performance of several VIs to estimate NNI in sweet pepper (Capsicum annuum). The performance of VIs to estimate NNI was evaluated using parameters of linear regression analysis conducted for calibration and validation. Three different sweet pepper crops were grown with combined irrigation and fertigation, in Almería, Spain. In each crop, five different N concentrations in the nutrient solution were frequently applied by drip irrigation. Proximal crop reflectance was measured with Crop Circle ACS470 and GreenSeeker handheld sensors, approximately every ten days, throughout the crops. The relative performance of VIs differed between phenological stages. Relationships of VIs with NNI were strongest in the early fruit growth and flowering stages, and less strong in the vegetative and harvest stages. The green band-based VIs, GNDVI, and GVI, provided the best results for estimating crop NNI in sweet pepper, for individual phenological stages. GNDVI had the best performance in the vegetative, flowering, and harvest stages, and GVI had the best performance in the early fruit growth stage. Some of the VIs evaluated are promising tools to estimate crop N status in sweet pepper and have the potential to contribute to improving crop N management of sweet pepper crops.

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Use of fluorescence indices as predictors of crop N status and yield for greenhouse sweet pepper crops

Precision Agriculture ◽

10.1007/s11119-021-09837-4 ◽

2021 ◽

Author(s):

Romina de Souza ◽

M. Teresa Peña-Fleitas ◽

Rodney B. Thompson ◽

Marisa Gallardo ◽

Rafael Grasso ◽

...

Keyword(s):

Optical Sensors ◽

Management Practices ◽

N Uptake ◽

Relative Yield ◽

Sweet Pepper ◽

Growth Stages ◽

N Content ◽

Fluorescence Measurements ◽

N Management ◽

N Status

AbstractTo increase nitrogen (N) use efficiency and reduce water pollution from vegetable production, it is necessary to optimize N management. Fluorescence-based optical sensors are devices that can improve N fertilization through non-destructive field monitoring of crop variables. The aim of this work was to compare the performance of five fluorescence indices (SFR-R, SFR-G, FLAV, NBI-R, and NBI-G) to predict crop variables, as dry matter production, crop N content, crop N uptake, Nitrogen Nutrition Index (NNI), absolute and relative yield, in sweet pepper (Capsicum annuum) crops grown in greenhouse. Fluorescence measurements were periodically made with the Multiplex® 3.6 sensor throughout three cropping cycles subjected to five N application treatments. The performance of fluorescence indices to predict crop variables considered calibration and validation analyses. In general, the five fluorescence indices were strongly related with NNI, crop N content and relative yield. The best performing indices to predict crop N content and NNI at the early stages of the crops (i.e., vegetative and flowering phenological stages) were the SFR indices, both under red (SFR-R) and green (SFR-G) excitation. However, in the final stage of the crop (i.e., harvest stage), the best performing indices were NBI, both under red (NBI-R) and green (NBI-G) excitation, and FLAV. The two SFR indices best predicted relative yield of sweet pepper at early growth stages. Overall, the fluorescence sensor and the fluorescence indices evaluated were able to predict crop variables related to N status in sweet pepper. They have the capacity to be incorporated into best N management practices.

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On-farm soil N supply and N nutrition in the rice–wheat system of Nepal and Bangladesh

Field Crops Research ◽

10.1016/s0378-4290(99)00063-5 ◽

1999 ◽

Vol 64 (3) ◽

pp. 273-286 ◽

Cited By ~ 55

Author(s):

C Adhikari ◽

K.F Bronson ◽

G.M Panuallah ◽

A.P Regmi ◽

P.K Saha ◽

...

Keyword(s):

Soil N ◽

N Nutrition ◽

N Supply ◽

On Farm

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Multispectral Assessment of Sweet Pepper (Capsicum annuum L.) Fruit Quality Affected by Calcite Nanoparticles

Biomolecules ◽

10.3390/biom11060832 ◽

2021 ◽

Vol 11 (6) ◽

pp. 832

Author(s):

Monika Vidak ◽

Boris Lazarević ◽

Marko Petek ◽

Jerko Gunjača ◽

Zlatko Šatović ◽

...

Keyword(s):

Convex Hull ◽

Capsicum Annuum ◽

Fruit Quality ◽

Sweet Pepper ◽

Quality Analysis ◽

Morphological Properties ◽

Agricultural Practice ◽

Vegetable Crops ◽

Physiological Maturity ◽

Capsicum Annuum L

Sweet pepper (Capsicum annuum L.) is one of the most important vegetable crops in the world because of the nutritional value of its fruits and its economic importance. Calcium (Ca) improves the quality of sweet pepper fruits, and the application of calcite nanoparticles in agricultural practice has a positive effect on the morphological, physiological, and physicochemical properties of the whole plant. The objectives of this study were to investigate the effect of commercial calcite nanoparticles on yield, chemical, physical, morphological, and multispectral properties of sweet pepper fruits using a combination of conventional and novel image-based nondestructive methods of fruit quality analysis. In the field trial, two sweet pepper cultivars, i.e., Šorokšari and Kurtovska kapija, were treated with commercial calcite nanoparticles (at a concentration of 3% and 5%, calcite-based foliar fertilizer (positive control), and water (negative control) three times during vegetation). Sweet pepper fruits were harvested at the time of technological and physiological maturity. Significant differences were observed between pepper cultivars as well as between harvests times. In general, application of calcite nanoparticles reduced yield and increased fruit firmness. However, different effects of calcite nanoparticles were observed on almost all properties depending on the cultivar. In Šorokšari, calcite nanoparticles and calcite-based foliar fertilizers significantly increased N, P, K, Mg, Fe, Zn, Mn, and Cu at technological maturity, as well as P, Ca, Mg, Fe, Zn, Mn, Cu, and N at physiological maturity. However, in Kurtovska kapija, the treatments increased only Ca at technological maturity and only P at physiological maturity. The effect of treatments on fruit morphological properties was observed only at the second harvest. In Šorokšari, calcite nanoparticles (3% and 5%) increased the fruit length, minimal circle area, and minimal circle radius, and it decreased the fruit width and convex hull compared to the positive and negative controls, respectively. In Kurtovska kapija, calcite nanoparticles increased the fruit width and convex hull compared to the controls. At physiological maturity, lower anthocyanin and chlorophyll indices were found in Kurtovska kapija in both treatments with calcite nanoparticles, while in Šorokšari, the opposite effects were observed.

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A steady-state N balance approach for sustainable smallholder farming

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2106576118 ◽

2021 ◽

Vol 118 (39) ◽

pp. e2106576118

Author(s):

Yulong Yin ◽

Rongfang Zhao ◽

Yi Yang ◽

Qingfeng Meng ◽

Hao Ying ◽

...

Keyword(s):

Steady State ◽

Management Practices ◽

Global Climate ◽

N Balance ◽

Smallholder Farming ◽

N Losses ◽

Application Range ◽

High Yields ◽

N Management ◽

On Farm

Hundreds of millions of smallholders in emerging countries substantially overuse nitrogen (N) fertilizers, driving local environmental pollution and global climate change. Despite local demonstration-scale successes, widespread mobilization of smallholders to adopt precise N management practices remains a challenge, largely due to associated high costs and complicated sampling and calculations. Here, we propose a long-term steady-state N balance (SSNB) approach without these complications that is suitable for sustainable smallholder farming. The hypothesis underpinning the concept of SSNB is that an intensively cultivated soil–crop system with excessive N inputs and high N losses can be transformed into a steady-state system with minimal losses while maintaining high yields. Based on SSNB, we estimate the optimized N application range across 3,824 crop counties for the three staple crops in China. We evaluated SSNB first in ca. 18,000 researcher-managed on-farm trials followed by testing in on-farm trials with 13,760 smallholders who applied SSNB-optimized N rates under the guidance of local extension staff. Results showed that SSNB could significantly reduce N fertilizer use by 21 to 28% while maintaining or increasing yields by 6 to 7%, compared to current smallholder practices. The SSNB approach could become an effective tool contributing to the global N sustainability of smallholder agriculture.

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Single and split nitrogen dose in wheat yield indicators

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/1807-1929/agriambi.v22n1p16-21 ◽

2018 ◽

Vol 22 (1) ◽

pp. 16-21 ◽

Cited By ~ 2

Author(s):

Juliane S. P. Costa ◽

Rubia D. Mantai ◽

José A. G. da Silva ◽

Osmar B. Scremin ◽

Emilio G. Arenhardt ◽

...

Keyword(s):

Block Design ◽

Wheat Yield ◽

N Use Efficiency ◽

Phenological Stages ◽

Split Dose ◽

N Supply ◽

N Release ◽

Residual N ◽

Use Efficiency ◽

N Use

ABSTRACT Single or split nitrogen (N) supply can maximize the expression of wheat yield indicators. The objective of the study was to evaluate the greater N use efficiency on wheat yield indicators by the single and split N supply under favorable and unfavorable year conditions to the crop in succession system of high and reduced residual N release. The study was conducted in 2014 and 2015, in a randomized complete block design with four replicates in a 4 x 3 factorial, for N-fertilizer doses (0, 30, 60, 120 kg ha-1) and supply forms [full dose (100%) in the phenological stage V3 (third expanded leaf); split dose (70 and 30%) in the phenological stages V3/V6 (third and sixth expanded leaves, respectively) and; split dose (70 and 30%) in the phenological stages V3/R1 (third expanded leaf and early grain filling)], respectively, in soybean/wheat and maize/wheat cultivation systems. The highest N use efficiency for wheat yield was obtained with the single dose supply in favorable year of temperature and rainfall and with the split dose in the V3/V6 stages in unfavorable year, regardless of the succession system of high and reduced residual N release.

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Nitrogen Supply Influences Carbohydrate Partitioning of Pepper Seedlings and Transplant Development

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.116.6.995 ◽

1991 ◽

Vol 116 (6) ◽

pp. 995-999 ◽

Cited By ~ 7

Author(s):

Beny Aloni ◽

Tamara Pashkar ◽

Lea Karni ◽

Jaleh Daie

Keyword(s):

Soluble Sugar ◽

Leaf Age ◽

Carbohydrate Partitioning ◽

N Nutrition ◽

Post Transplant ◽

Nitrogen Levels ◽

Unit Leaf ◽

Leaf Chlorophyll ◽

N Supply ◽

Root Shoot Ratio

We investigated the effects of N nutrition on growth and carbohydrate partitioning of pepper (Capsicum annuum L., cv. Maor) seedlings in the greenhouse and on their subsequent recovery and development after transplanting. Seedlings received 0, 30, 100, or 200 mg N/liter for 14 days, after which they were transplanted and received 100 mg N/liter. Nitrogen levels below 100 mg·liter−1 inhibited shoot growth and leaf chlorophyll content; both were severely inhibited in the absence of supplemental N. Root growth had a negative relation with N supply; an enhanced root: shoot ratio was observed under low-N regimes. On a unit-leaf-area basis, CO2 fixation was not affected when N was present; however, it was greatly inhibited in the absence of N. Changes in the leaf starch and soluble sugar concentrations occurred as a function of N supply and leaf age. In the roots, low N led to lower sucrose and higher levels of hexose and starch. More sucrose was transported and accumulated into leaf veins of low-N tissue. Exogenously supplied 14C-labeled sucrose was rapidly converted into starch in the low-N tissue. Seedlings that received 100 mg N/liter had the highest post-transplant growth rate and flowered earlier. Carbohydrate status of young pepper seedlings influenced their post-transplant recovery. Optimal N supply is essential for full recovery and development of transplants.

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Powdery mildew of Allium species caused by Oidiopsis taurica in Brazil

Horticultura Brasileira ◽

10.1590/s0102-05362004000400018 ◽

2004 ◽

Vol 22 (4) ◽

pp. 758-760 ◽

Cited By ~ 3

Author(s):

Ailton Reis ◽

Leonardo S. Boiteux ◽

Milton L. Paz-Lima ◽

Patrícia P. Silva ◽

Carlos A. Lopes

Keyword(s):

Powdery Mildew ◽

Allium Sativum ◽

Leaf Surface ◽

Federal District ◽

Sweet Pepper ◽

Host Specialization ◽

Vegetable Crops ◽

Allium Species ◽

Powdery Mildew Disease ◽

Fungal Colony

Oidiopsis taurica Salmon (Syn. Oidiopsis sicula Scalia) was identified as the causal agent of a powdery mildew disease occurring on distinct Allium species in Brazil. This disease was initially observed in plastic house and field-grown garlic (Allium sativum) and leek (A. porrum) accessions in Brasília (Federal District) and in field-grown and greenhouse onion (A. cepa) cultivars in Belém do São Francisco (Pernambuco State) and Brasília, respectively. Typical symptoms consisted of chlorotic areas on the leaf surface corresponding to a fungal colony. These lesions turned to a brownish color with the progress of the disease. Fungi morphology was similar to that described for O. taurica. Endophytic mycelium emerging through estomata, light pale conidia were dimorphic (lanceolate primary conidia and somewhat cylindrical secondary conidia), fibrosin bodies were absent, conidia formed predominantly single (not in chains), and appressoria were non-lobed. Its sexual stage, Leveillula taurica (Lev.) Arnaud, was not observed. Inoculations were performed with the O. taurica isolates from distinct Allium hosts. These isolates were also pathogenic to sweet pepper and tomato, indicating an apparent absence of host specialization. One bunching onion (A. fistulosum) accessions was not infected by O. taurica suggesting that this species might carry useful resistance alleles to this pathogen. This is the first formal report of a powdery mildew disease on species of the genus Allium in Brazil. This disease might become important on these vegetable crops especially in hot and dry areas such as those in the Central and Northeast regions of Brazil.

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