scholarly journals Improving indirect measurements of the leaf area index using canopy height

Author(s):  
Alexandre Ortega Gonçalves ◽  
Evandro Henrique Figueiredo Moura da Silva ◽  
Letícia Gonçalves Gasparotto ◽  
Juliano Mantelatto Rosa ◽  
Stephanie do Carmo ◽  
...  

Abstract: The objective of this work was to evaluate the use of plant height as a calibration variable for improving indirect measurements of the leaf area index (LAI). Three experiments were conducted with different crops - corn (Zea mays), soybean (Glycine max), and sugarcane (Saccharum officinarum) -, to compare the performance of the LAI measured indirectly (LAIind) and corrected by the calibration variable with the LAI measured directly (LAIref). Without the proposed correction, the LAIind tended to be overestimated by 20%, on average, compared with the LAIref, for the three crops. After crop height was used to adjust the LAIind, a strong positive relationship was observed between the LAIref and the corrected LAIind (R2 = 0.96); overestimation was reduced to 4% and the root-mean-square error decreased to 0.35 m2 m-2. The variable canopy height is promising for the correction of the LAI of the soybean, corn, and sugarcane crops.

2017 ◽  
Vol 16 (3) ◽  
pp. 460
Author(s):  
EMERSON TROGELLO ◽  
LUAN FERREIRA BORGES ◽  
FÁBIO ARAÚJO DE OLIVEIRA ◽  
QUÉZIA SANCHES MUTAGUTI ◽  
INGRID GOMIDES BARROS ◽  
...  

RESUMO - O objetivo deste estudo foi avaliar as características morfoagronômicas do híbrido simples de milho em função da aplicação de diferentes intensidades de desfolha artificial, realizadas no estádio R1 de desenvolvimento. O experimento foi conduzido na área experimental do Instituto Federal Goiano,em Morrinhos-GO, na safra 2015/2016. Foi aplicado o delineamento de blocos completamente casualizados, com oito tratamentos e quatro repetições, sendo eles: remoção de uma folha acima e uma abaixo da espiga; remoção de duas folhas acima e abaixo da espiga; remoção de três folhas acima e abaixo da espiga; remoção de todas as folhas da planta; remoção de todas as folhas acima da espiga; remoção de todas as folhas abaixo da espiga; remoção da folha da espiga; e testemunha sem desfolha. Os caracteres avaliados foram: estande de plantas, número de plantas acamadas, prolificidade, densidade de colmo, comprimento e diâmetro de espiga, comprimento de grão, massa de mil grãos, massa de grãos espiga-1 e produtividade. Os dados foram submetidos à análise de variância pelo teste F a 5% de probabilidade, observando que todas as variáveis avaliadas foram influenciadas quanto aos efeitos dos tratamentos empregados. O enchimento dos grãos esteve intimamente relacionado à fotossíntese. Sem as folhas, esta fase ficou plenamente comprometida.Palavras-chave: Zea mays, fotoassimilados, translocação, índice de área foliar, rendimento. MORPHOAGRONOMIC CHARACTERISTICS OF MAIZE AS A FUNCTION OF DIFFERENT LEVELS OF ARTIFICIAL DEFOLIATION  ABSTRACT - The objective of this study was to evaluate of morphoagronomic characteristics of simple hybrids of maize, depending on the application of different intensities of artificial defoliation, carried out in R1, when the style-stigma were fertilized. The experiment was conducted in an experimental area of the Instituto Federal Goiano, Campus Morrinhos, State of Goiás, Brazil, during the agricultural year 2015/2016. We applied the design of completely randomized block with eight treatments, in four replications: removal of a leaf above and one below the ear; removal of two leaves above and below the ear; removal of three leaves above and below the ear; removal of all leaves of the plant; removal of all leaves above the ear; removal of all leaves below the ear; removal of the leaf of the ear; and control without defoliation. The traits evaluated were stand of plants, number of plant lodging, prolificacy, density, length and diameter of the cob, length of a grain, weight of a thousand grains, grain mass cob-1 and productivity. The data obtained were subjected to analysis of variance by F test at 5% probability, noting that all variables were influenced as to the effects of the treatments used. The filling of grains is closely related to photosynthesis. Without the leaves, this phase was fully damaged.Keywords: Zea mays L., photoassimilates, translocation, leaf area index, yield.


1998 ◽  
Vol 91 (1-2) ◽  
pp. 69-88 ◽  
Author(s):  
Christopher J Kucharik ◽  
John M Norman ◽  
Stith T Gower

2014 ◽  
Vol 151 ◽  
pp. 44-56 ◽  
Author(s):  
Gong Zhang ◽  
Sangram Ganguly ◽  
Ramakrishna R. Nemani ◽  
Michael A. White ◽  
Cristina Milesi ◽  
...  

Forests ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 26 ◽  
Author(s):  
John Iiames ◽  
Ellen Cooter ◽  
Donna Schwede ◽  
Jimmy Williams

2014 ◽  
Vol 2 (1) ◽  
pp. 31 ◽  
Author(s):  
Janerson J. Coêlho ◽  
José C.B. Dubeux Jr ◽  
Erick R.S. Santos ◽  
João M.C. Leão Neto ◽  
Márcio V. Da Cunha ◽  
...  

2013 ◽  
Vol 04 (03) ◽  
pp. 575-583 ◽  
Author(s):  
Jean-Claude Lukombo Lukeba ◽  
Roger Kizungu Vumilia ◽  
Kabwe C. K. Nkongolo ◽  
Moïse Lufuluabo Mwabila ◽  
Mbungu Tsumbu

1972 ◽  
Vol 52 (1) ◽  
pp. 112-115 ◽  
Author(s):  
David J. Major ◽  
Terrance B. Daynard

not available


Sign in / Sign up

Export Citation Format

Share Document