Derivation of Leaf-Area Index from Quality of Light on the Forest Floor

Ecology ◽  
1969 ◽  
Vol 50 (4) ◽  
pp. 663-666 ◽  
Author(s):  
Carl F. Jordan
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Forest Floor ◽  
Area Index

The effect of planting date and nitrogen management on yield and quality of aromatic rice (Oryza sativa)

2004 ◽  
Vol 142 (2) ◽  
pp. 183-191 ◽  
Author(s):  
M. GHOSH ◽  
B. K. MANDAL ◽  
B. B. MANDAL ◽  
S. B. LODH ◽  
A. K. DASH
Keyword(s):  
Oryza Sativa ◽  
Grain Yield ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Amylose Content ◽  
Aromatic Rice ◽  
Area Index ◽  
Growth Environment ◽  
Yield And Quality

Growth environment and plant nutrition are two important factors influencing growth, yield and quality of aromatic rice (Oryza sativa L.). The present study was conducted at Kalyani, India to determine the effect of two planting dates and four fertilizer levels on different aromatic rice cultivars during the dry seasons of 1995/96 and 1996/97, while nine cultivars were evaluated during the wet seasons of 1996 and 1997. Thermal and photoperiodic conditions significantly influenced the vegetative (leaf area index and light extinction co-efficient) and reproductive (filled spikelets/panicle) growth of the crop. Delayed planting (23 February) significantly reduced the grain yield by 0·88 t/ha, amylose content by 0·5% and duration by 10 days; but increased the summed heliothermal units (17806 v. 18505). Thus, the cultivars became less efficient (27%) in heat use with delay in planting from 2 to 23 February. Relative availability of NH4+-N from urea and Azolla influenced the crop growth (leaf area index [LAI], tiller production and leaf chlorophyll content) and nutrient uptake. Supply of inorganic N either alone or in conjunction with Azolla significantly increased grain yield (18–41%) and protein content (0·1–0·7%) over 15 t/ha of Azolla alone. However, combined application of Azolla and urea lowered the amylose content below that achieved by application of either substance alone. Correlation studies among quality attributes indicated that long-grained varieties had lower head rice recovery (r=−0·69) due to more breakage during milling and greater test weight (r=0·93).

scholarly journals Evaluation of the growth and quality of lettuce (Lactuca sativa L.) in a closed recirculating hydroponic system

2017 ◽  
Vol 35 (2) ◽  
pp. 216-222 ◽  
Author(s):  
Rafael David Fraile-Robayo ◽  
Javier Giovanni Álvarez-Herrera ◽  
Andrea Johana Reyes M. ◽  
Omar Ferney Álvarez-Herrera ◽  
Ana Lucía Fraile-Robayo
Keyword(s):  
Growth Rate ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Calcium Nitrate ◽  
Potassium Nitrate ◽  
Area Index ◽  
Hydroponic System ◽  
Physiological Variables ◽  
Over Time

The production of lettuce in hydroponic systems with a recirculating nutrient solution has been growing, so it is necessary to evaluate the growth and quality of production under this system. Two harvest cycles were evaluated, comparing the behavior of physiological variables and growth rates on lettuce plants in a hydroponic system with a plastic cover. Lettuce plants were planted at 30 days after germination in an NFT hydroponic system. Nutrient solutions were prepared with sources of potassium nitrate, calcium nitrate, urea phosphate, magnesium sulfate and a source of minor nutrifeed. The second cycle had the highest total dry mass and leaf area index (LAI) at 43 days after transplant (dat). The relative growth rate (RGR) declined over time. The absolute growth rate (AGR) presented a sigmoid behavior as a gaussian bell shape; the leaf area index (LAI) increased until 43 dat, with the second cycle presenting the highest value; the net assimilation rate (NAR) decreased over time, with the second cycle having the highest value at 22 dat. The chlorophyll content for this variety was low, with a yellow pigmentation in the plant. The stomatal conductance (SC) in the two cycles at transplant time presented low values caused by the stress leaded by an imbalance in the pH of the solution, when the plants adapted to the system, this value increased.

The quality of short-wave radiation within plant canopies

1969 ◽  
Vol 47 (12) ◽  
pp. 1989-1994 ◽  
Author(s):  
T. B. Daynard
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Communities ◽  
Short Wave ◽  
Wave Radiation ◽  
Leaf Angle ◽  
Visible Radiation ◽  
Area Index ◽  
Plant Canopies

In this paper, a mathematical attempt is made to predict the effects of leaf area index, leaf angle, and leaf spectral properties on changes in the relative composition of short-wave radiant fluxes as they penetrate plant canopies. Results of this theoretical analysis indicate that a sizeable change in the quality of visible radiation will only occur if the canopy is sufficiently dense to intercept at least 98% of the incident flux one or more times. By contrast, a significant increase in the proportion of infrared radiation is predicted within plant communities, even those of a low effective leaf area index. For natural plant communities, the results would indicate a minimal change in the composition of penetrating radiation at solar noon and a maximal change at sunrise or sunset.The implications of these phenomena to plant morphogenesis and to radiation-measuring techniques are discussed.

scholarly journals An Empirical Protocol for Indirect Measurement of Leaf Area Index in Grape (Vitis vinifera L.)

HortScience ◽  
1993 ◽  
Vol 28 (8) ◽  
pp. 777-779 ◽  
Author(s):  
David A. Grantz ◽  
Larry E. Williams
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Canopy Structure ◽  
Indirect Measurement ◽  
Vitis Vinifera L ◽  
Indirect Methods ◽  
Area Index ◽  
Wide Row Spacing ◽  
Radiation Sensors

Leaf area development and canopy structure are important characteristics affecting yield and fruit quality of grapevines. Trellising systems and wide row spacing are common viticultural practices that violate key assumptions of currently available indirect methods of leaf area determination. We have developed a protocol for using a commercially available instrument to determine leaf area index (LAI) indirectly in a trellised vineyard. From knowledge of plant spacing, leaf area per vine can be calculated as required. A derived calibration equation resulted in a near 1:1 relationship (y = 0.00 + 1.00 X; r2 = 0.998) between actual and indirectly determined LAI over a range of LAI induced by irrigation treatments. The protocol involved covering 75% of the sensor with a manufacturer-supplied field of view delimiter and masking data from the outer three (of five) concentric radiation sensors. The protocol could form the basis for a general measurement technique, but may require local calibration.

scholarly journals Leaf Area Index, Water Index, and Red: Far Red Ratio Calculated by Spectral Reflectance and its Relation to Plant Architecture and Cut Rose Production

2006 ◽  
Vol 131 (3) ◽  
pp. 313-319 ◽  
Author(s):  
Libertad Mascarini ◽  
Gabriel A. Lorenzo ◽  
Fernando Vilella
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Spectral Reflectance ◽  
Limiting Factor ◽  
Simple Method ◽  
Area Index ◽  
Water Index ◽  
Significant Difference ◽  
Shoot System

In roses (Rosa ×hybrida L.), the bending of branches is a technique that modifies the canopy of the plant and could affect such parameters as the leaf area index (LAI), the quality of reflected light, and the water index (WI) of the plant. The measurement of spectral reflectance with remote sensors is a nondestructive, quick, and simple method to study these parameters. The aim of this paper is to quantify the modification of reflected radiation quality, the LAI and the water index of the plant with different canopies, and its impact on flowering and the number and quality of flowers produced. In R. ×hybrida `Terracotta', using the spectral crop reflectance, the red: far red ratio [red (R) = 680 nm; far red (FR) = 730 nm], percentage of blue light of reflected radiation, and vegetation indices [normalized difference vegetation index (NDVI), simple ratio index (SRI), water index (WI)] were calculated in two architectural managements: traditional (upright hedge) and bent shoot. NDVI had a greater correlation with LAI than SRI (r2 = 0.98 and 0.85, respectively), but SRI was more reliable for LAI values of 1 to 3.5. The bent shoot system compared to the traditional one decreased the R:FR ratio of reflected radiation and increased LAI and plant water content. These changes were related to a higher commercial quality of the flowers (longer flowering shoots with a larger stem diameter and fresh weight), although there was no significant difference in the number of flowers harvested. The period that showed the largest difference in the quality of the flower using the bent shoot system had a LAI of 2.8 vs. 1.8 with traditional management and a marked reduction in the R:FR of the light reflected by bent plants. The bent shoot system advanced the peak production by 1 month at the end of winter and improved the flowers at a time when sun radiation is limiting factor for production.

Effects of treated municipal wastewater on fluctuation trend of leaf area index and quality of maize (Zea mays)

2013 ◽  
Vol 67 (4) ◽  
pp. 797-802 ◽  
Author(s):  
Sayed Roholla Mousavi ◽  
Mohammad Galavi ◽  
Hamdollah Eskandari
Keyword(s):  
Zea Mays ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Municipal Wastewater ◽  
Clean Water ◽  
Area Index ◽  
Growing Period ◽  
Significant Difference ◽  
Treated Municipal Wastewater

The effect of primary-treated municipal wastewater (TMWW) on the leaf area index (LAI) and quality of maize (Zea mays) was studied in comparison to the clean irrigation water (control). The experiment was based on a randomized block design with four replicates, and it was conducted in a field experiment in Aligoudarz (Iran). Irrigation was applied with five different methods as treatments: T1: irrigation with clean water during whole growing period (control); T2: 75% clean water and 25% TMWW; T3: 50% clean water and 50% TMWW; T4: 25% clean water and 75% TMWW; T5: irrigation with TMWW during whole growing period. Results showed that irrigation with TMWW had a significant positive impact on all characters compared with the control. Maximum LAI was yielded on the 80th day after emergence in T4. Use of TMWW increased seed oil to 5.85%, which was 29.2% more than that in the control. Maximum values for percentage of protein, total dry matter and phosphorus concentration were obtained in T5. Maximum zinc concentration (15.93 mg kg−1) was obtained in T4; it was 8% more than the control. According to the results there was no significant difference in treatment T4 and T5.

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