An Approach for Indirect Determination of Leaf Area Index

2019 ◽  
Vol 62 (3) ◽  
pp. 655-659 ◽  
Author(s):  
Sally D. Logsdon ◽  
Cindy A. Cambardella

Abstract. Leaf area index (LAI) is important in crop models, but determination of LAI can be challenging for crops and mixtures of crops. The purpose of this study was to determine LAI indirectly from ground cover (determined from photographic images) and canopy height using defined relationships based on crop coefficients. Images of plant canopies were obtained to estimate the green cover fraction. An equation was derived to determine LAI from ground cover and plant height, and the technique was tested on different crops. For three of the measurement dates, the data were compared to LAI measurements obtained with a LAI-2200 plant canopy analyzer. The trend was the same for the two LAI procedures, but there was some scatter. The photographic technique was adequate for LAI determination. Keywords: Ground cover, Plant canopy cover, Plant height.

Author(s):  
Andreas Klingler ◽  
Andreas Schaumberger ◽  
Francesco Vuolo ◽  
László B. Kalmár ◽  
Erich M. Pötsch

2016 ◽  
Vol 123 ◽  
pp. 195-202 ◽  
Author(s):  
Marco Mora ◽  
Felipe Avila ◽  
Marcos Carrasco-Benavides ◽  
Gonzalo Maldonado ◽  
Jeissy Olguín-Cáceres ◽  
...  

2013 ◽  
Vol 5 (2) ◽  
pp. 371-381 ◽  
Author(s):  
K. K. Paul ◽  
M. A. B. Miah

An investigation has been made to characterize the local accessions of Elephant foot yam collected from thirteen aroid growing districts and in-depth study on genetic variability, correlation and path coefficient for plant height, petiole length, petiole breadth, leaf area index, corm length, corm breadth, corm weight, cormel number, cormel length, cormel breadth, cormel weight and yield per plant has also been carried out. Genotypic variances and coefficient of variation for most of the characters were remarkably higher than their corresponding environmental variances, which also indicate the existence of variation in genotypic origin. High heritability with high genetic advance in percentage of mean was also observed for all characters. In the correlation study plant height, leaf area index, corm length, corm breadth, corm weight, cormel number, cormel length, cormel breath showed positive correlation with yield per plant in genotypic and phenotypic level. Leaf area index, cormel number in phenotypically and cormel number in genotypic level showed relatively high positive direct effect on yield per plant.Keywords: Amorphophallus; Genetic variability; Correlation; Path coefficient.© 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v5i2.13853        J. Sci. Res. 5 (2), 371-381 (2013)


2016 ◽  
Vol 15 (4) ◽  
pp. 191-197 ◽  
Author(s):  
B.P. Lena ◽  
M.V. Folegatti ◽  
J.P. Francisco ◽  
O.N.A. Santos ◽  
I.P.S. Andrade

2018 ◽  
Vol 228 ◽  
pp. 195-203 ◽  
Author(s):  
Ben Zhao ◽  
Syed Tahir Ata-Ul-Karim ◽  
Aiwang Duan ◽  
Zhandong Liu ◽  
Xiaolong Wang ◽  
...  

1996 ◽  
Vol 21 (1) ◽  
pp. 241-241
Author(s):  
Gene Burris ◽  
Don Cook ◽  
B. R. Leonard ◽  
J. B. Graves ◽  
J. Pankey

Abstract The test was conducted at the Northeast Research Station in St. Joseph, LA. Plots were replicated 4 times in a RCB design and were four rows (40-inch spacing) X 65 ft. ‘Stoneville LA 887’ cotton seed was planted 2 and 3 May on a commerce silt soil which was fertilized sidedress with 90 lb N/acre. Cotton seed were planted with a John Deere model 7100 series planter which was equipped with 10 inch seed cones mounted to replace the seed hoppers. The seed rate was 4 seed/row ft. Granular in-furrow treatments were applied with 8 inch belt cone applicators mounted to replace the standard granular applicators. Control of thrips and aphids was evaluated on 5 randomly selected plants/plot. Evaluations were made on 18, 19, 24, 26, and 29 May and 8 Jun. Plant height counts were taken on 10 randomly selected plants/plot on 8 Jun. Stand density and leaf area was determined by counting the number of plants in a randomly selected meter on 29 May. Leaf area was recorded using a Li Cor leaf area machine. The data was recorded as cm2 and converted to a leaf area index (LAI). Major pests and/or secondary pest control was initiated in Jun and continued on an “as needed” basis through Aug.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Samuel Maina ◽  
Rossa Nyoike Ng’endo

Maize (Zea mays L.) is a significant food security crop in Kenya and it serves as the main source of nutrition and calories among the small-holder farmers. The overall maize yields per hectare have been fluctuating in the past few years posing a great risk to food security. Among the stress factors associated with maize yield loss include plant-feeding nematodes. In this regard, this study was conducted to evaluate the impacts of plant-parasitic nematodes specifically Scutellonema spp. under field conditions on maize performance in Mwea, Kenya. The field trials were laid out in a randomized complete block design with each treatment comprising of four replicates. The treatments included maize plots without nematicide (MPWN) and control plots treated with nematicide. The experiments were conducted in two trials. Soil samples were taken at a 0–20 cm depth at monthly intervals during 2018–2019. During the two trials, MPWN recorded significantly lower plant height and number of leaves per plant. Correlation analysis revealed a significant negative relationship between Scutellonema abundance with leaf area index, plant height, and number of functional leaves in MPWN during the 2019 trial. This implies that high population of Scutellonema perhaps has the potential to affect leaf area index, plant height, number of leaves per plant, which are aspects that in turn influence maize productivity. Therefore, holistic sustainable management practices to control Scutellonema spp. in maize fields such as use of organic amendments, resistant maize cultivars, and antagonistic organisms are crucial in order to alleviate negative impacts linked to Scutellonema infestation.


Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 6 ◽  
Author(s):  
Milad Mahmoodzadeh ◽  
Phalguni Mukhopadhyaya ◽  
Caterina Valeo

A comprehensive parametric analysis was conducted to evaluate the influence of the green roof design parameters on the thermal or energy performance of a secondary school building in four distinctively different climate zones in North America (i.e., Toronto, ON, Canada; Vancouver, BC, Canada; Las Vegas, NV, USA and Miami, FL, USA). Soil moisture content, soil thermal properties, leaf area index, plant height, leaf albedo, thermal insulation thickness and soil thickness were used as design variables. Optimal parameters of green roofs were found to be functionally related to meteorological conditions in each city. In terms of energy savings, the results showed that the light-weight substrate had better thermal performance for the uninsulated green roof. Additionally, the recommended soil thickness and leaf area index for all four cities were 15 cm and 5 respectively. The optimal plant height for the cooling dominated climates is 30 cm and for the heating dominated cities is 10 cm. The plant albedo had the least impact on the energy consumption while it was effective in mitigating the heat island effect. Finally, unlike the cooling load, which was largely influenced by the substrate and vegetation, the heating load was considerably affected by the thermal insulation instead of green roof design parameters.


2017 ◽  
Vol 5 (4) ◽  
pp. 423-429 ◽  
Author(s):  
Mohan Mahato ◽  
Bishnu Bilas Adhikari

A field experiment was conducted under humid subtropical agro-climatic condition of Nepal during rainy season of 2014. The experiment was laid out in to two factor Randomized Complete Block Design with  three replications consisting three drought tolerant rice varieties (Sukhadhan-4, Sukhadhan-5 and Radha-4) and four planting geometry (15 cm × 10 cm, 15 cm × 15 cm, 20 cm × 15 cm and 20 cm × 20 cm). The results revealed that the highest plant height and maximum leaf area index was recorded in planting geometry 15 cm × 10 cm in all growth stages. Whereas, planting geometry 20 cm × 15 cm produced the maximum number of tiller m-2 in all growth stage.  While planting geometry 20 cm × 15 cm and 20 cm × 20 cm produced statistically similar crop growth rate and dry matter accumulation in all stage of growth. Regarding the varieties, Sukhadhan- 4 showed highest plant height up to 75 DAT and plant height was statistically similar to Radha - 4 in 60 and 75 DAT. But maximum number of tiller m-2, leaf area index, crop growth rate and dry matter accumulation were recorded in Sukhadhan – 5 varieties. Int. J. Appl. Sci. Biotechnol. Vol 5(4): 423-429


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