Escala diagramática de quantificação de dano causado por granizo em folhas de girassol

Lucas, Dionéia Daiane Pitol; Heldwein, Arno Bernardo; Maldaner, Ivan Carlos; Dalcin, J. S.; Loose, Luís Henrique

doi:10.1590/s1806-66902012000400026

Cited by 4 publications

(3 citation statements)

References 13 publications

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“…Knowledge on leaf area is essential to estimate parameters such as leaf area index, specific leaf area, net assimilation rate and leaf area ratio, used for growth analysis. In addition, it is possible to develop diagrammatic scales for the evaluation of damage caused by biotic and abiotic factors that occur in plants (Lima, Martins, Viana, & Cardoso, 2018;Lucas, Heldwein, Maldaner, Dalcin, & Loose, 2012).…”

Section: Modelagem Trigo Sarracenomentioning

confidence: 99%

Estimation of buckwheat leaf area by leaf dimensions

Filho¹,

Pezzini²,

Neu³

et al. 2021

Semina: Ciênc. Agrár.

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The objective of this work was to model and identify the best models for estimating the leaf area, determined by digital photos, of buckwheat (Fagopyrum esculentum Moench) of the cultivars IPR91-Baili and IPR92-Altar, as a function of length (L), width (W) or length x width product (LW) of the leaf blade. Ten uniformity trials (blank experiments) were carried out, five with IPR91-Baili cultivar and five with IPR92-Altar cultivar. The trials were performed on five sowing dates. In each trial and cultivar, expanded leaves were collected at random from the lower, middle and upper segments of the plants, totaling 1,815 leaves. In these 1,815 leaves, L and W were measured and the LW of the leaf blade was calculated, which were used as independent variables in the model. The leaf area of each leaf was determined using the digital photo method (Y), which was used as a dependent variable of the model. For each sowing date, cultivar and thirds of the plant, 80% of the leaves (1,452 leaves) were randomly separated for the generation of the models and 20% of the leaves (363 leaves) for the validation of the models of leaf area estimation as a function of linear dimensions. For buckwheat, IPR91-Baili and IPR92-Altar cultivars, the quadratic model (Ŷ = 0.5217 + 0.6581LW + 0.0004LW2, R2 = 0.9590), power model (Ŷ = 0.6809LW1.0037, R2 = 0.9587), linear model (Ŷ = 0.0653 + 0.6892LW, R2 = 0.9587) and linear model without intercept (Ŷ = 0.6907LW, R2 = 0.9587) are indicated for the estimation of leaf area determined by digital photos (Y) based on the LW of the leaf blade (x), and, preferably, the linear model without intercept can be used, due to its greater simplicity.

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Section: Modelagem Trigo Sarracenomentioning

confidence: 99%

Estimation of buckwheat leaf area by leaf dimensions

Filho¹,

Pezzini²,

Neu³

et al. 2021

Semina: Ciênc. Agrár.

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“…Agricultural activities are often exposed to biotic and abiotic stresses such as the occurrence of hail or severe attack by defoliating pests which are often controlled with the use of insecticides indiscriminately, to carry out photosynthetically maintenance of the active leaf area. After the adoption of appropriate criteria for diagnosing the damages and losses in productivity caused by the loss of leaf area, it can facilitate decision-making to solve the problem by the grower or technician (Lucas, Heldwein, Maldner, Dalcin, & Loose, 2012). Some studies were carried out in maize, where Carvalho et al (2021) showed that defoliation after the flowering stage reduces, on average, 79.6% in grain yield.…”

Section: Introductionmentioning

confidence: 99%

Artificial defoliation and its impact on the agronomic performance of sunflower in a non-preferential season

Meotti,

Carvalho,

Loro

et al. 2023

Agron. Sci. Biotechnol.

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The objective of this work was to evaluate the partitioning of photoassimilates in sunflower plants sown in a non-preferential season coincident with the occurrence of fallow areas in the region, submitted to artificial defoliation with 100% intensity, in different phenological stages of the reproductive period. The experimental design used was randomized blocks with six treatments and three replications, consisting of 18 experimental units and all plants were defoliated. The treatments performed were artificial defoliation, I: No defoliation (control); II: Defoliation at the R1 phenological stage; III: Defoliation at the R3 phenological stage; IV: Defoliation at the R5 phenological stage; V: Defoliation at the R7 phenological stage and VI: Defoliation at the R8 phenological stage. Artificial defoliation performed at 100% intensity at different phenological stages influences the morphological attributes and yield components of sunflower in a distinct way. Defoliations performed at R1 phenological stage have a negative effect on most of the variables analyzed, which provided lower plant height, stem diameter, capitulum diameter, number of rows of achenes, number of achenes per row, achene length, achene width, thousand achene mass and, consequently, in grain yield. This phenological stage was marked by the beginning of the reproductive period, which has a high demand for photoassimilates to maintain plant metabolism and yield. Defoliation performed at R8 phenological stage had better performance for plant height, capitulum diameter, capitulum mass, number of rows of achenes, number of achenes per row, number of plants per hectare and grain yield (>1000 kg ha-1). The plants of experimental units without defoliation had results similar to those defoliated in the R8 phenological stage, however, they still had better performance for thousand achene mass, achene length, achene width, volume index and even a smaller diameter of missing seeds.

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“…Os trabalhos sobre simulação de danos foliares, como os que acontecem por granizo (Lucas et al, 2012), geralmente são realizados com desfolha artificial de folhas inteiras, o que não representa fielmente o dano físico causado em condições de lavoura. Conley et al (2008) simularam três níveis de intensidade de desfolha artificial (25, 50 e 75%) em quatro estádios de desenvolvimento (V3, V6, R1 e R3.5).…”

Section: Introductionunclassified

Dano por Granizo na Cultura da Soja em Condições de Lavoura: Um Estudo de Caso

Ceolin

Streck

Zanon

et al. 2016

Rev. bras. meteorol.

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ResumoO objetivo deste trabalho foi quantificar os danos causados por um evento de granizo sobre uma lavoura comercial de soja. O evento de granizo ocorreu no município de Água Santa, no Estado do Rio Grande do Sul, durante o ano agrícola de 2013/2014. Foram realizadas avaliações da matéria seca do limbo foliar, pecíolo, legume e do índice de área foliar. Tais medições foram obtidas em data anterior e posterior ao evento de granizo que ocorreu no dia 08/02/2014. Com o auxílio de imagens de satélites e de radar foi possível identificar a intensidade do evento e a presença de granizo nas nuvens. Os danos provocados pelo granizo na cultura da soja foram: a redução da matéria seca nos limbos foliares (0,13 Mg ha -1 ), nos pecíolos (0,01 Mg ha -1 ) e nos legumes (0,002 Mg ha -1 ) das plantas da lavoura; o decréscimo no índice de área foliar de 7 a 34%; e a quebra do ápice de crescimento em 32% das plantas do experimento. Possivelmente, devido a esta redução na massa seca, houve diminuição na produtividade de soja da lavoura. As imagens de satélite e de radar podem ser ferramentas para auxiliar os extensionistas na determinação dos danos de granizo nas lavouras de soja. Palavras-chave: Glycine max, índice de área foliar, granizo, radares meteorológicos. On-Farm Hail Damage In Soybean: A Case Study AbstractThe objective of this study was to quantify the damages caused by a hail event on a soybean farm. The hail event happened at Água Santa County, Rio Grande do Sul State, Brazil, during the 2013/2014 growing season. Were conducted dry matter evaluations of leaf, petiolate, pod and leaf area index. Such measurements were obtained before and also after of the hail event occurred on 08/02/2014. By using satellite and radar images it was possible to identify the hail event intensity. The hail event damage on the soybean crop were reduction dry matter on leaf blade (0.13 Mg ha ), also were observed a decrease in leaf area index that varying from 7 to 34% and breaking off the growth apex in 32% of plants on the experiment. Therewith, the satellite and radar images can be a tool to help the extension on determination of hail damage on soybean farms.

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Escala diagramática de quantificação de dano causado por granizo em folhas de girassol

Cited by 4 publications

References 13 publications

Estimation of buckwheat leaf area by leaf dimensions

Estimation of buckwheat leaf area by leaf dimensions

Artificial defoliation and its impact on the agronomic performance of sunflower in a non-preferential season

Dano por Granizo na Cultura da Soja em Condições de Lavoura: Um Estudo de Caso

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