Replacing the nitrogen nutrition index by the chlorophyll meter to assess wheat 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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Chlorophyll meter–based nitrogen fertilizer optimization algorithm and nitrogen nutrition index for in‐season fertilization of paddy rice

Agronomy Journal ◽

10.1002/agj2.20036 ◽

2020 ◽

Vol 112 (1) ◽

pp. 288-300 ◽

Cited By ~ 1

Author(s):

Ke Zhang ◽

Zhaofeng Yuan ◽

Tiancheng Yang ◽

Zhenzhou Lu ◽

Qiang Cao ◽

...

Keyword(s):

Optimization Algorithm ◽

Nitrogen Fertilizer ◽

Nitrogen Nutrition ◽

Paddy Rice ◽

Chlorophyll Meter ◽

Nitrogen Nutrition Index

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Nitrogen nutrition index and forage yield explain nitrogen utilization efficiency in hybrid ryegrasses under different nitrogen availabilities

Field Crops Research ◽

10.1016/j.fcr.2021.108101 ◽

2021 ◽

Vol 265 ◽

pp. 108101

Author(s):

Patricio Sandaña ◽

Iris A. Lobos ◽

Paula B. Pavez ◽

Cristian J. Moscoso

Keyword(s):

Nitrogen Nutrition ◽

Nitrogen Utilization ◽

Forage Yield ◽

Utilization Efficiency ◽

Nitrogen Utilization Efficiency ◽

Nitrogen Nutrition Index

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Can PocketNNI, a new smart app for Nitrogen Nutrition Index estimation, reduce the environmental impact of rice?

10.1109/metroagrifor52389.2021.9628796 ◽

2021 ◽

Author(s):

Livia Paleari ◽

Michele Zoli ◽

Jacopo Bacenetti ◽

Roberto Confalonieri

Keyword(s):

Environmental Impact ◽

Nitrogen Nutrition ◽

Nitrogen Nutrition Index ◽

Index Estimation

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LEAF TOTAL NITROGEN CONCENTRATION AS AN INDICATOR OF NITROGEN STATUS FOR PLANTLETS AND YOUNG PLANTS OF EUCALYPTUS CLONES

Revista Brasileira de Ciência do Solo ◽

10.1590/01000683rbcs20140689 ◽

2015 ◽

Vol 39 (4) ◽

pp. 1127-1140 ◽

Cited By ~ 4

Author(s):

Eric Victor de Oliveira Ferreira ◽

Roberto Ferreira Novais ◽

Bruna Maximiano Médice ◽

Nairam Félix de Barros ◽

Ivo Ribeiro Silva

Keyword(s):

Total Nitrogen ◽

Block Design ◽

Nitrogen Concentration ◽

Soil N ◽

Total N ◽

Chlorophyll Meter ◽

N Concentration ◽

Total Nitrogen Concentration ◽

N Status ◽

Leaf N

The use of leaf total nitrogen concentration as an indicator for nutritional diagnosis has some limitations. The objective of this study was to determine the reliability of total N concentration as an indicator of N status for eucalyptus clones, and to compare it with alternative indicators. A greenhouse experiment was carried out in a randomized complete block design in a 2 × 6 factorial arrangement with plantlets of two eucalyptus clones (140 days old) and six levels of N in the nutrient solution. In addition, a field experiment was carried out in a completely randomized design in a 2 × 2 × 2 × 3 factorial arrangement, consisting of two seasons, two regions, two young clones (approximately two years old), and three positions of crown leaf sampling. The field areas (regions) had contrasting soil physical and chemical properties, and their soil contents for total N, NH+4-N, and NO−3-N were determined in five soil layers, up to a depth of 1.0 m. We evaluated the following indicators of plant N status in roots and leaves: contents of total N, NH+4-N, NO−3-N, and chlorophyll; N/P ratio; and chlorophyll meter readings on the leaves. Ammonium (root) and NO−3-N (root and leaf) efficiently predicted N requirements for eucalyptus plantlets in the greenhouse. Similarly, leaf N/P, chlorophyll values, and chlorophyll meter readings provided good results in the greenhouse. However, leaf N/P did not reflect the soil N status, and the use of the chlorophyll meter could not be generalized for different genotypes. Leaf total N concentration is not an ideal indicator, but it and the chlorophyll levels best represent the soil N status for young eucalyptus clones under field conditions.

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Soil Monitoring Methods to Assess Immediately Available Soil N for Fertigated Sweet Pepper

Agronomy ◽

10.3390/agronomy10122000 ◽

2020 ◽

Vol 10 (12) ◽

pp. 2000

Author(s):

Alejandra Rodríguez ◽

M. Teresa Peña-Fleitas ◽

Francisco M. Padilla ◽

Marisa Gallardo ◽

Rodney B. Thompson

Keyword(s):

Soil Solution ◽

Nitrogen Nutrition ◽

Sweet Pepper ◽

Vegetable Production ◽

Soil N ◽

Monitoring Methods ◽

N Application ◽

Nitrogen Nutrition Index ◽

Greenhouse Vegetable ◽

Combined Data

Excessive N application occurs in greenhouse vegetable production. Monitoring methods of immediately available soil N are required. [NO3−] in soil solution, sampled with ceramic cup samplers, and [NO3−] in the 1:2 soil to water (v/v) extract were evaluated. Five increasing [N], from very N deficient (N1) to very N excessive (N5) were applied throughout three fertigated pepper crops by combined fertigation/drip irrigation. The crops were grown in soil in a greenhouse. Soil solution [NO3−] was measured every 1–2 weeks, and extract [NO3−] every 4 weeks. Generally, for treatments N1 and N2, both soil solution and extract [NO3−] were continually close to zero, and increased with applied [N] for treatments N3–5. The relationships of both methods to the nitrogen nutrition index (NNI), an indicator of crop N status, were assessed. Segmented linear analysis gave R2 values of 0.68–0.70 for combined data from entire crops, for both methods. NNI was strongly related to increasing [NO3−] up to 3.1 and 0.9 mmol L−1 in soil solution and extracts, respectively. Thereafter, NNI was constant at 1.04–1.05, with increasing [NO3−]. Suggested sufficiency ranges were derived. Soil solution [NO3−] is effective to monitor immediately available soil N for sweet pepper crops in SE Spain. The extract method is promising.

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Critical Nitrogen Curve and Nitrogen Nutrition Index for Potato in Eastern Canada

American Journal of Potato Research ◽

10.1007/bf02884344 ◽

2001 ◽

Vol 78 (5) ◽

pp. 355-364 ◽

Cited By ~ 91

Author(s):

G. Bélanger ◽

J. R. Walsh ◽

J. E. Richards ◽

P. H. Milburn ◽

N. Ziadi

Keyword(s):

Nitrogen Nutrition ◽

Eastern Canada ◽

Nitrogen Nutrition Index

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Using simple RGB Camera to estimate Nitrogen Uptake, Nitrogen Nutrition Index (NNI) and critical Nitrogen: Spring wheat case study.

10.5194/egusphere-egu2020-5769 ◽

2020 ◽

Author(s):

Jiftah Ben-Asher

Keyword(s):

Spring Wheat ◽

Dry Matter ◽

Nitrogen Nutrition ◽

N Uptake ◽

Maximum Yield ◽

Digital Camera ◽

Growth Period ◽

Growth Cycle ◽

Nitrogen Nutrition Index ◽

Grain Unit

The first Nc dilution curve was based on dry matter (DM) power function. This model is limited to&#160; point of singularity near zero. Another disadvantage was that it required meaasurements of DM which is time and labor consuming. Alternatively we proposed a logistic model that starts at zero and on the abscissa assumed a linear relationship between days after emergence (DAE) and DM throughout the relevant stages of wheat growth cycle. &#160;The Objectives of this study were to: 1) To demonstrate the feasibility of digital camera to replace laboratory tests. 2) To Determine critical N (Nc) and Nitrogen nutrition Index(NNI) of spring wheat and 3) Use N% and dry matter yield in order to calculate N uptake by wheat. This last is expected to be a tool to calculate the required amount of nitrogen to obtain maximum yield.Wheat experiments were conducted in greenhouse lysimeters. Varied rates of N fertilizer (equivalent to 0&#8211;180 kg ha-1) and several&#160; cultivars varying from shortest to longest ripening growth period. Nc reduced gradually from about 6% to 2%&#160; ( =60-20 gr/Kg) when DM increased with DAE&#160; from 0 to 14,000 kg/ha during 80 growing days.&#160; NNI was stable and clearly distinct between &#160;&#160;maximal index (1.0 &#160;and minimal index (0.2) when (DAE) was about 60;&#160;&#160; Photographs succeeded to replicate laboratory measurements and obtained a linear regression curve with a unity&#160; slop and r2=0.93. Nitrogen.&#160; use efficiency (NUE) ranged from 50 to 65 kg&#160; DM/unit N and from 30 to 50 Kg grain /unit N&#160;.

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