The leaf area of an Australian heathland with reference to seasonal changes and the contribution of individual species

1968 ◽  
Vol 16 (3) ◽  
pp. 579 ◽  
Author(s):  
R Jones
Keyword(s):  
Leaf Area ◽  
Seasonal Changes ◽  
Individual Species ◽  
Seasonal Growth ◽  
Seasonal Fluctuations ◽  
Total Leaf Area ◽  
Area Index ◽  
Total Community ◽  
Community Area ◽  
Community Growth

The leaf area of an Australian heathland was determined on harvested material for a series of monthly harvests over 2 years. The leaf area index (LAI) varied from 1 .8 to 3.2. Seasonal growth flushes accounted for the high values, while leaf fall induced by water stress restored the equilibrium to approximately 2.0. The dominant shrub, Leptospermum myrsinoides, contributed 53.5% of the total leaf area, and this species alone caused the seasonal fluctuations in community area. Only three other species contributed more than 5 % to the total. Community growth was characterized by the behaviour of L. myrsinoides. Detailed analyses of this species showed the need for seasonal measurements to fully describe the LAI of evergreen communities.

scholarly journals High NDVI and Potential Canopy Photosynthesis of South American Subtropical Forests despite Seasonal Changes in Leaf Area Index and Air Temperature

Forests ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 287-308 ◽  
Author(s):  
Piedad Cristiano ◽  
Nora Madanes ◽  
Paula Campanello ◽  
Débora di Francescantonio ◽  
Sabrina Rodríguez ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Air Temperature ◽  
Seasonal Changes ◽  
South American ◽  
Canopy Photosynthesis ◽  
Area Index ◽  
Subtropical Forests

Seasonal changes of leaf area index (LAI) in a tropical deciduous forest in west Mexico

1995 ◽  
Vol 74 (1-3) ◽  
pp. 171-180 ◽  
Author(s):  
JoséManuel Maass ◽  
James M. Vose ◽  
Wayne T. Swank ◽  
Angelina Martínez-Yrízar
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Seasonal Changes ◽  
Deciduous Forest ◽  
Tropical Deciduous Forest ◽  
Area Index ◽  
West Mexico

Leaf Area and Competition for Light between Plant Species using Direct Sunlight Transmission

1988 ◽  
Vol 2 (2) ◽  
pp. 159-165 ◽  
Author(s):  
Graham K. Walker ◽  
Robert E. Blackshaw ◽  
Jack Dekker
Keyword(s):  
Leaf Area ◽  
Plant Species ◽  
Chenopodium Album ◽  
Field Studies ◽  
Individual Species ◽  
Light Competition ◽  
Direct Sunlight ◽  
Area Index ◽  
Wild Mustard ◽  
Competition For Light

A technique based on the relationship between leaf area index (LAI) and the transmittance of direct sunlight was developed for thein situstudy of competition for light between plant species. Field studies were conducted in 1984 and 1985 using monocultures and mixtures of rapeseed (Brassica napusL.), wild mustard (Sinapis arvensisL. # SINAR), and common lambsquarters (Chenopodium albumL. # CHEAL). LAI estimated nondestructively by this method agreed closely with LAI determined by conventional destructive techniques. Light measurements at several heights in the canopy were used to determine the vertical distribution of canopy leaf area. Combining this information with species heights allowed the separation of the canopy LAI into individual species LAI, from which light competition could be estimated by calculating the sunlit LAI of each species. The technique permits many detailed measurements in the same canopy throughout the growing season. The light sensor required is not costly and is simple to operate and to maintain.

scholarly journals Physiological indexes of mini tomato cultivars grown in a protected environment

2020 ◽  
Vol 36 (5) ◽  
Author(s):  
Diego Rangel da Silva Gama ◽  
Kalline Mendes Ferreira ◽  
Vanuza de Souza ◽  
Jony Eishi Yuri ◽  
Alessandro Carlos Mesquita
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Growth Analysis ◽  
The Other ◽  
Control Treatment ◽  
Total Leaf Area ◽  
Area Index ◽  
Physiological Indexes ◽  
Tomato Cultivars ◽  
Plant Sampling

Shading screens are widely used to control excessive solar radiation, thereby changing plant growth. Thus, through physiological indices the objective was to evaluate the growth of three cultivars of minitomatoes under colored meshes. The experiment was conducted from April to July in the DTCS / UNEB experimental field in experiment DBC with subdivided plots, and four replicates, comprised of three shaded environments and the control treatment, three cultivars, and seven plant sampling seasons. For growth analysis, we used the destructive method, total dry matter was determined after drying it in an oven at 65°C. The total leaf area (LAI) was obtained using the software QUANT. Results showed that there was no interaction between environments and the other factors. Regarding leaf area index, cvs. Shani and Sweet Million stood out in all environments, whereas cv. Red Sugar had a similar behavior in all environments. Shani obtained the best indices in open sun environment and in the environment covered with red shading screen, and Sweet Million obtained the best index under gray shading screen. Red Sugar had the lowest LAI, and consequently, the lowest SLA and LAR. On the other hand, it showed the highest RPF, since it obtained the highest dry matter in leaves compared to the other cultivars. Cvs. Shani and Sweet Million showed the best: TAL, TCR, TCA and TCC.

GROWTH AND DRY MATTER (FODDER) PRODUCTION OF MAIZE (Zea mays L.) VARIETIES AS AFFECTED BY TIMING OF NITROGEN SECOND DOSE FERTILIZATION

2021 ◽  
Vol 4 (4) ◽  
pp. 96-107
Author(s):  
Muhammad Kabir Ladan ◽  
Hassan Adamu Hamidu ◽  
Abdul Bamidele Lawal ◽  
Abdullahi Namakka
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Sea Level ◽  
Dry Matter ◽  
Dry Matter Production ◽  
Total Leaf Area ◽  
Area Index ◽  
Matter Production ◽  
Maize Varieties ◽  
Number Of Leaves

ABSTRACT Field trials were conducted in 2016 wet season at Institute of Agricultural Research IAR, Research Farm(Lat.11o 11’ N, Long. 07038’ E, 686m above sea level), Samaru-Zaria and Jaji Military Cantonment Farm located at 30 Km from Zaria along Kaduna – Zaria road (Lat. 10o 49’ 25” N, Long. 07o 34’ 10” E, 600m above sea level), both in Northern Guinea Savannah of Nigeria, to Investigate the growth of Maize varieties and dry matter produced at varying timing of nitrogen second dose fertilization. The treatments consist of three maize varieties (SAMMAZ 14, SAMMAZ 15 and SAMMAZ 16) and six times of nitrogen second dose fertilization 4 5, 6, 7, 8, 9 weeks after sowing (WAS). Treatments were factorially combined and laid out in a randomized complete block design (RCBD) with three replications. SAMMAZ 16 outperformed SAMMAZ 14 and SAMMAZ 15 in terms of plant height, number of leaves, total leaf area, leaf area index and dry matter production. Time of nitrogen second dose application 6 WAS consistently produced the highest growth attributes of maize  ;plant height, number of leaves, total leaf area, leaf area index and dry matter production compared to other timings evaluated. SAMMAZ 16 and 6 WAS in conclusion appeared to be the optimum for increased maize fodder (dry matter) production in the Savannah region where potential for livestock production is high.

Vertical distribution of leaf area in Larixoccidentalis: a comparison of two estimation methods

1989 ◽  
Vol 19 (9) ◽  
pp. 1131-1136 ◽  
Author(s):  
William R. Bidlake ◽  
R. Alan Black
Keyword(s):  
Vertical Distribution ◽  
Leaf Area Index ◽  
Normal Distribution ◽  
Leaf Area ◽  
Stand Density ◽  
Total Leaf Area ◽  
Area Index ◽  
Total Leaf ◽  
Gap Fraction ◽  
The Vertical Distribution

Total leaf-area index and the vertical distribution of leaf-area index were described for an unthinned stand (density 11 250 stems/ha) and a thinned stand (density 1660 stems/ha) of 30-year-old Larixoccidentalis Nutt. Two independent methods were used to estimate leaf-area index in each of the two stands. The first method is based on allometric relationships that are applied to stem measurements, and the second method is based on gap-fraction analysis of fisheye photographs. Leaf-area index estimates obtained by the two methods were not significantly different. The gap-fraction method provides a desirable alternative because much less fieldwork is required, however, use of this method is limited to canopies where the light-blocking elements are randomly displayed. Total leaf-area index values for the unthinned and thinned stands were 5.0 and 3.6, respectively. The vertical distribution of leaf-area index in the unthinned stand resembled a normal distribution. The vertical distribution of leaf-area index in the thinned stand would have resembled a normal distribution, except that thinning operations resulted in a truncated distribution of leaf-area index at the canopy base.

On improving the accuracy of digital hemispherical photography measurements of seasonal leaf area index variation in deciduous broadleaf forests

2015 ◽  
Vol 45 (6) ◽  
pp. 721-731 ◽  
Author(s):  
Zhili Liu ◽  
Xingchang Wang ◽  
Jing M. Chen ◽  
Chuankuan Wang ◽  
Guangze Jin
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Seasonal Changes ◽  
Optical Methods ◽  
Hemispherical Photography ◽  
Area Index ◽  
Clumping Index ◽  
Area Variation ◽  
Major Factors

Optical methods have been widely used to estimate seasonal changes of the leaf area index (LAI) in forest stands because they are convenient and effective; however, their accuracy in deciduous broadleaf forests has rarely been evaluated. We estimate the seasonal changes in the LAI by combining periodic observations of leaf area variation with litter collection (LAIdir) in deciduous broadleaf forests and use these estimates to evaluate the accuracy of optical LAI measurements made using digital hemispherical photography (DHP). We also propose a method to correct DHP-derived LAI (LAIDHP) values for seasonal changes in major factors that influence the determination of LAI, including the woody to total area ratio (α), the element clumping index (ΩE, using three different methods), and the photographic exposure setting (E). Before these corrections were made, LAIDHP underestimates LAIdir by 14%–55% from 21 May to 1 October but overestimates it by 78% on 12 May and by 226% on 11 October. Although pronounced differences are observed between LAIdir and LAIDHP, they are significantly correlated (R2 = 0.85, RMSE = 0.32, P < 0.001). After considering seasonal changes in α, ΩE, and E, the accuracy of LAIDHP improves markedly, with a mean difference between the corrected LAIDHP and LAIdir of <17% in all periods. The results suggest that the proposed scheme for correcting LAIDHP is useful and effective for estimating seasonal LAI variation in deciduous broadleaf forests.

The seasonal growth characteristics of irrigated cotton in a dry monsoonal environment

1965 ◽  
Vol 16 (3) ◽  
pp. 347 ◽  
Author(s):  
WR Stern
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Growth Rates ◽  
Dry Matter ◽  
Seasonal Effect ◽  
Cotton Yield ◽  
Seasonal Growth ◽  
Seed Cotton ◽  
Area Index ◽  
Seed Cotton Yield

Cotton plantings were made at the Kimberley Research Station (128° 36´ E., 15° 42´ S.) from September to July to give overlapping growth curves extending from September 1961 to December 1962. Crop growth was examined in relation to radiation and temperature. Beginning at the third week from sowing, each planting was sampled 12 times at intervals of 15 days. At each sampling, dry matter, leaf area index, number and dry weight of bolls, and seed cotton yield were determined. The development of total dry matter and leaf area index showed a strong seasonal trend. The number of bolls produced was less in the late plantings, and the seed cotton yield was correspondingly lower. The highest seed cotton yields and the highest ratios of seed cotton to total dry matter (30%) were obtained with January–February plantings. The growth rates between 50 and 100 days were used to analyse seasonality; the highest seasonal growth rate was 164 mg dm-2 day-1 in December–January and the lowest value was zero in early September. By using fitted harmonics, a multiple correlation was established between maximum and minimum temperatures and growth rates 30 days later. Potential rates of net photosynthesis of tops were calculated from observed radiation data with the use of the de Wit model and with allowance for light wastage, root growth, and respiration. There was good agreement between observed and potential growth rates from December to April. Midday stomatal apertures declined from November to May, and this appeared to be a seasonal effect. An annual pattern for the diffusive resistance of carbon dioxide through the leaf surface into the substomatal cavities is calculated. Radiation did not appear to be the primary limiting factor, and the seasonal growth pattern was interpreted in terms of the composite effect of maximum and minimum temperatures on extension growth, stomatal opening, and the presence or absence of suitable sinks for carbohydrates. Growth rates are evaluated against rates observed elsewhere, and means of exploiting the Kimberley environment are discussed.

Seasonal Changes in Leaf Area Index and Chlorophyll in an Indian Grassland

1981 ◽  
Vol 69 (3) ◽  
pp. 797 ◽  
Author(s):  
M. K. Misra ◽  
B. N. Misra
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Seasonal Changes ◽  
Area Index
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