scholarly journals Leaf area index and radiation extinction coefficient of a coffee canopy under variable drip irrigation levels

2019 ◽  
Vol 41 ◽  
pp. e42703 ◽  
Author(s):  
Jéfferson de Oliveira Costa ◽  
Rubens Duarte Coelho ◽  
Timóteo Herculino da Silva Barros ◽  
Eusímio Felisbino Fraga Júnior ◽  
André Luís Teixeira Fernandes
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Extinction Coefficient ◽  
Drip Irrigation ◽  
Deficit Irrigation ◽  
Area Index ◽  
Irrigation Level ◽  
Mean Error ◽  
The Mean ◽  
Irrigation Levels

The leaf area index (LAI) is relevant in studies of phenomena at different scales, such as for the leaf to canopy scale and the calculation of the extinction coefficient of photosynthetically active radiation (kPAR), providing input for the parameterization of physiological basis models. The objective of this work was to verify the variation of the LAI and the coffee kPAR subjected to different drip irrigation levels (130, 100, 70, and 40%) and to compare the data obtained from radiation bar linear sensors (SunScan) in the plants that received full irrigation with the values found by other LAI estimation methodologies. The study was conducted in Piracicaba, São Paulo State, Brazil, using the species Coffea arabica cv. Red Catuaí IAC 144; a drip irrigation system was adopted, with the irrigation controlled by tensiometry. The mean LAI values were higher in the L130 (irrigation level of 130%) and L100 (irrigation level of 100%) treatments than those with deficit irrigation depths. The mean kPAR values were lower for the L130 and L100 treatments than the values found in the deficit irrigation depth treatments. When comparing SunScan to other methodologies, the mean error (ME) and absolute mean error (AME) were high.

scholarly journals Remote Sensing to Study Mangrove Fragmentation and Its Impacts on Leaf Area Index and Gross Primary Productivity in the South of Peninsular Malaysia

2021 ◽  
Vol 13 (8) ◽  
pp. 1427
Author(s):  
Kasturi Devi Kanniah ◽  
Chuen Siang Kang ◽  
Sahadev Sharma ◽  
A. Aldrie Amir
Keyword(s):  
Remote Sensing ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Primary Productivity ◽  
Peninsular Malaysia ◽  
Area Index ◽  
Mangrove Area ◽  
The Mean ◽  
Shape Complexity ◽  
The Impact

Mangrove is classified as an important ecosystem along the shorelines of tropical and subtropical landmasses, which are being degraded at an alarming rate despite numerous international treaties having been agreed. Iskandar Malaysia (IM) is a fast-growing economic region in southern Peninsular Malaysia, where three Ramsar Sites are located. Since the beginning of the 21st century (2000–2019), a total loss of 2907.29 ha of mangrove area has been estimated based on medium-high resolution remote sensing data. This corresponds to an annual loss rate of 1.12%, which is higher than the world mangrove depletion rate. The causes of mangrove loss were identified as land conversion to urban, plantations, and aquaculture activities, where large mangrove areas were shattered into many smaller patches. Fragmentation analysis over the mangrove area shows a reduction in the mean patch size (from 105 ha to 27 ha) and an increase in the number of mangrove patches (130 to 402), edge, and shape complexity, where smaller and isolated mangrove patches were found to be related to the rapid development of IM region. The Moderate Resolution Imaging Spectro-radiometer (MODIS) Leaf Area Index (LAI) and Gross Primary Productivity (GPP) products were used to inspect the impact of fragmentation on the mangrove ecosystem process. The mean LAI and GPP of mangrove areas that had not undergone any land cover changes over the years showed an increase from 3.03 to 3.55 (LAI) and 5.81 g C m−2 to 6.73 g C m−2 (GPP), highlighting the ability of the mangrove forest to assimilate CO2 when it is not disturbed. Similarly, GPP also increased over the gained areas (from 1.88 g C m−2 to 2.78 g C m−2). Meanwhile, areas that lost mangroves, but replaced them with oil palm, had decreased mean LAI from 2.99 to 2.62. In fragmented mangrove patches an increase in GPP was recorded, and this could be due to the smaller patches (<9 ha) and their edge effects where abundance of solar radiation along the edges of the patches may increase productivity. The impact on GPP due to fragmentation is found to rely on the type of land transformation and patch characteristics (size, edge, and shape complexity). The preservation of mangrove forests in a rapidly developing region such as IM is vital to ensure ecosystem, ecology, environment, and biodiversity conservation, in addition to providing economical revenue and supporting human activities.

scholarly journals DESENVOLVIMENTO DO TOMATEIRO INDUSTRIAL EM RESPOSTA A DIFERENTES NÍVEIS DE IRRIGAÇÃO

Irriga ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 432-448
Author(s):  
Cícero José da Silva ◽  
José Antônio Frizzone ◽  
César Antônio da Silva ◽  
Nadson de Carvalho Pontes ◽  
Luiz Felipe Mariano da Silva ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Development ◽  
Tomato Plant ◽  
Dry Mass ◽  
Area Index ◽  
Tomato Plants ◽  
Subsurface Drip ◽  
Irrigation Levels ◽  
E Mail

DESENVOLVIMENTO DO TOMATEIRO INDUSTRIAL EM RESPOSTA A DIFERENTES NÍVEIS DE IRRIGAÇÃO     Cícero José da Silva1; José Antônio Frizzone2; César Antônio da Silva3; Nadson de Carvalho Pontes4; Luiz Felipe Mariano da Silva5 E Ênio Eduardo Basílio6   1Professor do Curso Bacharelado em Agronomia, Instituto Federal Goiano – Campus Morrinhos – GO, BR 153, Km 633, Zonal Rural, CEP;75650-000, Morrinhos – GO, Brasil. E-mail: [email protected] 2Professor Aposentado Colaborador Senior, Departamento de Engenharia de Biossitemas, Escola Superior de Agricultura “Luiz de Queiroz” – Universidade de São Paulo, Avenida Pádua Dias, N 11, Caixa Postal 9, CEP: 13418-900, Piracicaba – SP, Brasil. E-mail: [email protected] 3Professor do Curso Bacharelado em Agronomia, Instituto Federal Goiano – Campus Morrinhos – GO, BR 153, Km 633, Zonal Rural, CEP;75650-000, Morrinhos – GO, Brasil. E-mail: [email protected] 4Professor do Curso Bacharelado em Agronomia, Instituto Federal Goiano – Campus Morrinhos – GO, BR 153, Km 633, Zonal Rural, CEP;75650-000, Morrinhos – GO, Brasil. E-mail: [email protected] 5Estudante de Iniciação Científica do Curso Bacharelado em Agronomia, Instituto Federal Goiano – Campus Morrinhos – GO, BR 153, Km 633, Zonal Rural, CEP;75650-000, Morrinhos – GO, Brasil. E-mail: [email protected] 6Técnico Administrativo, Mestre em Olericultura, Instituto Federal Goiano – Campus Morrinhos – GO, BR 153, Km 633, Zonal Rural, CEP;75650-000, Morrinhos – GO, Brasil. E-mail: [email protected]     1 RESUMO   O objetivo desta pesquisa foi avaliar o desenvolvimento de plantas de tomateiros submetidas a diferentes níveis de reposição da irrigação, aplicados via sistema gotejamento subsuperficial durante duas safras. O experimento foi conduzido no delineamento em blocos ao acaso, com quatro repetições. Foram avaliados cinco níveis de irrigação: 50, 75, 100, 125 e 150% da evapotranspiração da cultura (%ETc) medida com lisímetros de pesagem, sobre o desenvolvimento de plantas de tomateiro. Cada parcela experimental foi composta por três fileiras de plantas de 5,5 m de comprimento, espaçadas a 1,10 m entre si e 0,30 m entre plantas. As avaliações de área foliar, índice de área foliar, massa seca de raiz, caule, folhas, flores, frutos e total foram realizadas aos 45, 65 e 85 dias após o transplante das mudas. Irrigações deficitárias e em excesso prejudicaram o desenvolvimento vegetativo das plantas de tomateiro. Os maiores valores de área foliar, índice de área foliar e massa seca total das plantas de tomateiro foram estimados com níveis de irrigação que variaram de 96 a 112% da ETc, variando de acordo com o ano de avaliação e a fase de desenvolvimento do tomateiro. Irrigações deficitárias e excessivas prejudicaram a floração e frutificação do tomateiro híbrido BRS Sena.             Palavras-chave: Solanum lycopersicom L.; gotejamento enterrado; manejo da irrigação; massa seca.             Silva, c. j. da; FRIZZONE, J. A.; SILVA, C. A. da; pontes, n. de C.; SILVA, L. F. M. da; BASÍLIO, Ê. E. Industrial tomato plant development in response to different irrigation levels    2 ABSTRACT   This research aimed to evaluate tomato plant development submitted to different irrigation replacement levels, irrigated via subsurface drip system for two harvests. The experiment was conducted under a randomized complete block design with four replications. Five irrigation levels were evaluated: 50, 75, 100, 125 and 150% of crop evapotranspiration (% ETc) measured with weighing lysimeters over the tomato plants development. Each experimental plot was composed of three plants rows with 5.5 m long, spaced 1.10 m apart and 0.30 m between plants. Leaf area, leaf area index, root dry matter, stem, leaves, flowers, fruits and total were evaluated at 45, 65 and 85 days after seedlings transplanting. Deficit and excess irrigation impaired the vegetative development of tomato plants. The highest values of leaf area, leaf area index and plants total dry mass were estimated with irrigation levels ranging from 96 to 112% of ETc, depending on the evaluation harvest year and the crop development phase. Deficit and excessive irrigation affected the flowering and fruiting of the hybrid tomato BRS Sena.   Keywords: Solanum lycopersicom L; subsurface drip irrigation; irrigation manegement; dry mass.

scholarly journals Management of Anthracnose in Common Bean by Foliar Sprays of Potassium Silicate, Sodium Molybdate, and Fungicide

Plant Disease ◽  
2014 ◽  
Vol 98 (1) ◽  
pp. 84-89 ◽  
Author(s):  
L. R. Polanco ◽  
F. A. Rodrigues ◽  
E. N. Moreira ◽  
H. S. S. Duarte ◽  
I. S. Cacique ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Sodium Molybdate ◽  
Potassium Silicate ◽  
Colletotrichum Lindemuthianum ◽  
Area Index ◽  
Healthy Leaf ◽  
Foliar Sprays ◽  
The Mean ◽  
Spray Treatment

This study aimed to determine whether foliar sprays of potassium silicate (KSi), sodium molybdate (NaMo), or a combination of both (KSi + NaMo), with or without the fungicide azoxystrobin (Azox), could reduce anthracnose symptoms and, consequently increase yield. Two two-by-four factorial experiments, consisting of untreated or fungicide treated, as well as sprays of KSi, NaMo, KSi + NaMo, and no spray (control), were arranged in a randomized block design with three replications. Treatments were as follows: treatment 1, KSi spray; treatment 2, NaMo spray; treatment 3, KSi + NaMo spray; treatment 4, Azox spray; treatment 5, Azox + KSi spray; treatment 6, Azox + NaMo spray, treatment 7, Azox + KSi + NaMo spray; and treatment 8, control (no KSi, NaMo, or Azox). The KSi, NaMo, and Azox treatments were sprayed at the rates of 35 g/liter, 90 g/ha, and 120 g a.i./ha, respectively. The KSi was applied at 20, 27, 40, and 55 days after sowing (das). The NaMo was sprayed only at 27 das whereas the fungicide was sprayed at 27, 40, and 55 das. Plants were inoculated with Colletotrichum lindemuthianum at 23 das. Azox reduced the mean area under disease progress curve (AUDPC) by 63% and mean yield was increased by 150%. Similarly, the mean AUDPC was reduced by 29, 14, and 41% with KSi, NaMo, and KSi + NaMo sprays, respectively, while mean yield increased by 13, 20, and 47%, with KSi, NaMo, or KSi + NaMo sprays, respectively. The variables leaf area index (LAI), leaf area index duration (LAD), healthy leaf area duration (HAD), and radiation intercepted (RI) were not affected by KSi spray. The values for the variables LAI, healthy leaf area index (HLAI), LAD, HAD, RI, intercepted radiation of the healthy leaf area, and healthy leaf area absorption were significantly increased as a result of NaMo spray. The results of the present study support the novel possibility of using a foliar spray of KSi in association with NaMo to decrease anthracnose symptoms in bean plants and, consequently, achieve greater yield.

scholarly journals Growth Response of Greenhouse-Produced Muskmelon and Tomato to Sub-Surface Drip Irrigation and Soil Aeration Management Factors

2019 ◽  
Author(s):  
Yuan Li ◽  
Wenquan Niu ◽  
Xiaoshu Cao ◽  
Mingzhi Zhang ◽  
Jingwei Wang ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Drip Irrigation ◽  
Dry Matter ◽  
Growth Response ◽  
Fruit Yield ◽  
Fractional Factorial ◽  
Area Index ◽  
Soil Aeration ◽  
Surface Drip Irrigation

Abstract Background: Hypoxia causes injury and yield loss. Soil aeration has been reported to accelerate the growth of plants and increase crop yield. The aim of this study was to examine growth response of greenhouse-produced muskmelon to 3 levels of sub-surface drip irrigation (I), 3 different installation depths of drip laterals in the soil (D), and 4 levels of supplemental soil aeration frequency (A). A fractional factorial experiment was designed to examine these treatment effects on marketable fresh fruit yield, leaf area index during 3 growth stages, and dry matter partitioning at harvest. In addition, we studied the response of fruit yield and dry matter of tomato to 2 levels of burial depths of subsurface tubing in combination with 3 frequency levels of soil aeration. Results: Results showed that soil aeration can positively influence the yield, leaf area index, dry matter and irrigation use efficiency of the muskmelon (p<0.05). The fruit yield of muskmelon and tomato were increased by 21.5% and 30.8% respectively with 1-d and 2-d aeration intervals compared with the no aeration treatment. Conclusions: The results suggest that soil aeration can positively impact the plant root zone environment and more benefits can be obtained with aeration for both muskmelon and tomato plants.

scholarly journals EVALUATION OF SIMPLE HAND-HELD MECHANICAL SYSTEMS FOR HARVESTING TEA (CAMELLIA SINENSIS)

2006 ◽  
Vol 42 (2) ◽  
pp. 165-187 ◽  
Author(s):  
P. J. BURGESS ◽  
M. K. V. CARR ◽  
F. C. S. MIZAMBWA ◽  
D. J. NIXON ◽  
J. LUGUSI ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Camellia Sinensis ◽  
Step Height ◽  
Area Index ◽  
Yield Increase ◽  
Coarse Material ◽  
Terminal Bud ◽  
The Mean

Over an eight-year period, harvesting methods based on simple mechanical aids (blade and shear) were evaluated against hand harvesting on mature morphologically contrasting tea clones in Southern Tanzania. The effects of shear step height (5–32 mm) and the harvest interval (1.8–4.2 phyllochrons) were also examined. Except in the year following pruning, large annual yields (5.7–7.9 t dry tea ha−1) were obtained by hand harvesting at intervals of two phyllochrons. For clones K35 (large shoots) and T207 (small shoots), the mean harvested shoot weights were equivalent to three unfurled leaves and a terminal bud. The proportions of broken shoots (40–48 %) and coarse material (4–6 %) were both relatively high. Using a blade resulted in similar yields to hand harvesting from K35 but larger yields from T207 (+13 %). The yield increase from clone T207 was associated with the harvest of more shoots and heavier shoots, smaller increases in canopy height, and a higher proportion (7–9 %) of coarse material compared to hand harvesting. On bushes, which had been harvested by hand for two years following pruning, using flat shears (no step) supported on the tea canopy resulted, over a three year period, in yields 8–14 % less than those obtained by hand harvesting and, for clone K35, a reduction in the leaf area index to below 5. The development of a larger leaf area index is made possible by adding a step to the shear. However, since annual yields were reduced by 40–50 kg ha−1 per mm increase in step height, the step should be the minimum necessary to maintain long-term bush productivity. As mean shoot weights following shear harvesting were about 13 % below those obtained by hand harvesting, there is scope, when using shears, to extend the harvest interval from 2 to 2.5 phyllochrons.

scholarly journals Monitoring leaf area index at watershed level through NDVI from Landsat-7/ETM+ data

2004 ◽  
Vol 61 (3) ◽  
pp. 243-252 ◽  
Author(s):  
Alexandre Cândido Xavier ◽  
Carlos Alberto Vettorazzi
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Vegetation Index ◽  
Hydrological Cycle ◽  
Riparian Forest ◽  
Empirical Relationships ◽  
Area Index ◽  
Landsat 7 ◽  
The Mean ◽  
The Relationship

Leaf area index (LAI) is an important parameter of the vegetation canopy, and is used, for instance, to estimate evapotranspiration, an important component of the hydrological cycle. This work analyzed the relationship between LAI, measured in field, and NDVI from four dates (derived from Landsat-7/ETM+ data), and with such vegetation index, to generate and analyze LAI maps of the study area for the diverse dates. LAI data were collected monthly in the field with LAI-2000 equipment in stands of sugar cane, pasture, corn, eucalypt, and riparian forest. The relationships between LAI and NDVI were adjusted by a potential model; 57% to 72% of the NDVI variance were explained by the LAI. LAI maps generated by empirical relationships between LAI and NDVI showed reasonable precision (standard error of LAI estimate ranged from 0.42 to 0.87 m² m-2). The mean LAI value of each monthly LAI map was shown to be related to the total precipitation in the three previous months.

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