scholarly journals The effect of light availability on leaf area index, biomass production and plant species composition of park grasslands in Warsaw  

2013 ◽  
Vol 59 (No. 12) ◽  
pp. 543-548 ◽  
Author(s):  
P. Dąbrowski ◽  
B. Pawluśkiewicz ◽  
Kalaji HM ◽  
Baczewska AH
Keyword(s):  
Solar Radiation ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Light Availability ◽  
Vegetation Coverage ◽  
Light Conditions ◽  
Area Index ◽  
Sward Height ◽  
Poa Trivialis ◽  
Leaf Density

How light conditions affect development of park grasslands is a question that has not been satisfactory addressed. The aim of this study was therefore determination of the level to which unfavorable light conditions influence grassy parks area and relationships between parameters which determine state of turf grasses. Researches were conducted in two parks in Warsaw, in various light conditions and included measurement of: leaf density, sward height, leaf area index (LAI), and botanical composition of the communities. The leaf density of shaded areas did not exceed 70%. LAI value varied from 0.5 to 0.9-fold lower than in the areas in half-shade and in sun. The participation of basic lawn species at Skaryszewski Park was higher under shade, while at Łazienki Królewskie was higher in full-sunlight areas. The state of tested grassy areas in limited solar radiation does not satisfy the requirements of recreational and representational functions. The development processes of vegetation coverage were inhibited at the sites of lower solar radiation. LAI was influenced by both leaf coverage and sward height. Agrostis stolonifera and Poa trivialis may be recommended to create grass areas under limited solar radiation.

scholarly journals Adjusting Ceptometer Data to Improve Leaf Area Index Measurements

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 866 ◽  
Author(s):  
Klára Pokovai ◽  
Nándor Fodor
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Measurement Techniques ◽  
Well Being ◽  
Average Error ◽  
Light Conditions ◽  
Simple Method ◽  
Area Index ◽  
Expert Opinions ◽  
Optimal Illumination

Leaf Area Index (LAI) is an important plant parameter for both farmers and plant scientists to monitor and/or model the growth and the well-being of plants. Since direct LAI measurement techniques are relatively laborious and time-consuming, various indirect methods have been developed and widely used since the early 1990s. The LP-80 ceptometer uses a linear array of PAR (photosynthetically active radiation) sensors for non-destructive LAI measurements that is backed by 15 years of research. Despite this, considerable discrepancy can be found between the expert opinions regarding the optimal illumination conditions recommended for the measurement. The sensitivity of ceptometer-based LAI values to PAR was investigated, and a simple method was devised to correct raw ceptometer data collected under non-ideal light conditions. Inadequate light conditions (PAR < 1700 µmol m−2 s−1) could cause an underestimation of LAI. Using the corrected LAI values, the ceptometer data showed a significantly better fit (higher R2, smaller mean average error and closer to zero mean signed error values) to the destructive LAI data for both wheat and maize. With the help of the correction equations, the use of the LP-80 ceptometer could be extended to days when light conditions are not ideal.

Photosynthesis of wheat under field conditions. IV. The influence of density and leaf area index on the response to radiation

1971 ◽  
Vol 22 (1) ◽  
pp. 11 ◽  
Author(s):  
DW Puckridge ◽  
DA Ratkowsky
Keyword(s):  
Carbon Dioxide ◽  
Solar Radiation ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Net Photosynthesis ◽  
Good Prediction ◽  
Area Index ◽  
Rectangular Hyperbola ◽  
Carbon Dioxide Uptake ◽  
Good Agreement

The photosynthesis of two cultivars of wheat at three densities of sowing was measured during the growing season of 1968. When the data were plotted as carbon dioxide uptake versus leaf area index (LAI) (leaf laminae and green stem) for a fixed value of solar radiation, it was found that all of the data could be fitted by a single curve, irrespective of variety, sowing density, or time of season when the measurements were made. Since the curve was of continuously decreasing slope, the carbon dioxide uptake per unit LAI was highest for the low values of LAI and was reduced with the increased light interception at high LAI. For a solar radiation of 0.6 cal/cm2/min the approximate maximum net photosynthesis was 4.5 g CO2/m2/hr for an LAI of 6. A mathematical model for photosynthesis was found to give good prediction of carbon dioxide uptake versus solar radiation for most of the period of measurement. For each plot, a rectangular hyperbola was fitted to the data. When the parameters of the model were subsequently plotted as a function of LAI, then within a given variety, it was found that lines of common slope but differing intercepts could be drawn through the points for different sowing densities. From these fitted lines together with the measured values of LAI and respiration, carbon dioxide uptake was then predicted as a function of solar radiation by employing the rectangular hyperbola model. Good agreement between predicted and measured values of photosynthesis was obtained.

scholarly journals PERTUMBUHAN DAN PRODUKSI PAPRIKA PADA BERBAGAI INTENSITAS RADIASI SURYA DI DATARAN RENDAH, BATAM(GROWTH AND PRODUCTION OF SWEET PEPPER CULTIVATED UNDER DIFFERENT SOLAR RADIATION INTENSITY AT LOWLAND REGION OF BATAM)

Agromet ◽  
2005 ◽  
Vol 19 (2) ◽  
pp. 57
Author(s):  
Z. Noor ◽  
B.F. Simatupang ◽  
Yonny Koesmaryono
Keyword(s):  
New Zealand ◽  
Solar Radiation ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Radiation Intensity ◽  
Ultra Violet ◽  
Sweet Pepper ◽  
Area Index ◽  
Hydroponic System ◽  
Solar Radiation Intensity

<p>An experiment has been conducted in Batam Island to study the response of sweet pepper which cultivated at lowland of 20 m asl, during November 2001 to May 2002. Five varieties have been used namely, Bangkok, Gold Flame, New Zealand, Spartacus and Tropica. Plants cultivated using hydroponic system under plastic house with ultra violet protection. The radiation of 100% (control) and it reduce of 25% and 50% used as treatment in order to determine the microclimate favourable for growing pepper in lowland. The results shown that reducing radiation intensity has influenced significantly on vegetatif growth, except leaf area index. The plants were grown under 100% and 25% radiation intensity performed taller with more branches compare to the plants under 50%. Variety of Spartacus has grew tallest than others. Stem diameter of control plants performed bigger than other plants, while reducing radiation intensity has no effect significantly to leaf area index. Experiment also revealed that reducing radiation intensity has significant effect on number and weight of peppers per plant, and thickness of flesh, compare to control. In general, Gold flame has produced best quality than others varieties although it has less number of fruits compare to Tropica.</p>

scholarly journals The Application of Modified Normalized Difference Water Index (MNDWI) by Leaf Area Index in the Retrieval of Regional Drought Monitoring

2015 ◽  
Vol XL-7/W3 ◽  
pp. 141-147
Author(s):  
H.-w. Zhang ◽  
H.-l. Chen
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Vegetation Coverage ◽  
Area Index ◽  
Water Index ◽  
Retrieval Accuracy ◽  
Normalized Difference Water Index ◽  
Green Stage

The vegetation coverage is one of the important factors that restrict the accuracy of remote sensing retrieval of soil moisture. In order to effectively improve the accuracy of the remote sensing retrieval of soil moisture and to reduce the impact of vegetation coverage variation on the retrieval accuracy, the Leaf Area Index (LAI) is introduced to the Normalized Difference Water Index (NDWI) to greatly improve the accuracy of the soil moisture retrieval. In its application on the regional drought monitoring, the paper uses the relative LAI from two places which locate in the north and south of Henan Province respectively (Xin Xiang and Zhu Ma Dian) as indicators. It uses the days after turned-green stage to conduct difference value correction on the Relative Leaf Area Index (RLAL) of the entire province, so as to acquire the distribution of RLAI of the province’s wheat producing area. After this, the local remote sensing NDWI will be Modified （MNDWI = NDWI ×RLAI ） to acquire the soil moisture distribution status of the entire province’s wheat producing area. The result shows that, the Modified Normalized Difference Water Index of LAI which based on the days after turned-green stage can improve the real time retrieval accuracy of soil moisture under different vegetation coverage.

The Extraction and Dynamic Monitoring of Leaf Area Index in Northeast of China Based on SPOT VEGETATION Data

2012 ◽  
Vol 500 ◽  
pp. 529-533
Author(s):  
Zheng Hong Miao ◽  
Zong Ming Wang ◽  
Jing Ming Chen ◽  
Kai Shan Song ◽  
Chun Ying Ren
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Liaoning Province ◽  
Dynamic Monitoring ◽  
Vegetation Coverage ◽  
Heilongjiang Province ◽  
Area Index ◽  
Increasing Trend ◽  
The Rich ◽  
Northeast Of China

Using SPOT VEGETATION data, the extraction method of experience model of LAI (leaf area index), we estimate and dynamic analysis the LAI of the northeast in 2000, 2004 and 2008. The results showed that: the LAI values of the Northeast region from 2000 to 2008 appears gradually increasing trend, the lowest average of 3.10 throughout the region in 2000, the highest in 2008, reaching 4.97. Judging from the different regions, changes in Liaoning province is the largest one which increases 136.40 points between 8 years, while Heilongjiang Province is the lowest, increased at only 21.53%. LAI values of Heilongjiang province are all the highest in 2000, 2004 and 2008 mainly because of the rich forest resources, vegetation coverage are relatively good; while in Liaoning province and Inner Mongolia, vegetation coverage is relatively poor. Therefore, the LAI is relatively low.

scholarly journals Conversion Efficiency of Photosynthetically Active Radiation for Soybean Cultivations in Spatial Arrangements

2019 ◽  
Vol 11 (9) ◽  
pp. 213
Author(s):  
Braulio Otomar Caron ◽  
Ana Paula Rockenbach ◽  
Denise Schmidt ◽  
Thaise Dieminger Engroff ◽  
Felipe Schwerz ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Conversion Efficiency ◽  
Photosynthetically Active Radiation ◽  
Area Index ◽  
Active Radiation ◽  
Soybean Cultivars ◽  
Growth Habits ◽  
Conversion Efficiencies

The objective of this paper was to assess the efficiency of photosynthetically active radiation (PAR) intercepted in dried phytomass of soybean cultivars of determinate and indeterminate growth habits in different spatial arrangements. All experiments were carried out during the 2013/2014 crop year, two soybean cultivars (BMX Ativa RR/determinate and BMX Turbo RR/indeterminate) in a spatial arrangements (45, crossed, 20, 20 &times; 40, 20 &times; 60, 20 &times; 80 cm). Starting from first emergence up to the point of maturation, 14 phytomass assessment were evaluated with seven days interval, in which one plant was sampled per repetition. Greater conversion efficiencies of solar radiation were obtained in paired arrangements. Paired arrangements, and 20 cm, lead to a greater leaf area index, and possibly a greater interception of the diffused radiation and an increase of conversion efficiency and the overall cultivation productivity of BMX Ativa RR and BMX Turbo RR.

Net assimilation rate of cotton in relation to spacing

1976 ◽  
Vol 86 (2) ◽  
pp. 281-285 ◽  
Author(s):  
J. G. Bhatt ◽  
R. C. Shah ◽  
A. N. Sharma
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Growth Habit ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Seed Cotton ◽  
Compact Type ◽  
Area Index ◽  
Leaf Density ◽  
Net Assimilation

SummaryThe net assimilation rates (NAR) of three genotypes of cotton differing in their growth habit were studied under different spacings. The NARs of a very bushy type, G 67, and a comparatively less spreading type, IAN 560, were the same but that of a compact type, IAN 579, was twice as much when the leaf area index (LAI) was one. Though subsequently in G 67 and IAN 560 NAR under varying spacings either decreased less rapidly or remained steady, the decrease was nearly Hnear with increasing LAI. However, for IAN 579 dependence of NAR on LAI was generally positive indicating genotypic improvement. Under different spacings the leaf-density dependance of NAR appeared to have been decreased in IAN 560, but was nearly absent in IAN 579 with more efficiency towards increasing the yield of seed cotton.

scholarly journals Effect of Solar Radiation on Severity of Soybean Rust

2012 ◽  
Vol 102 (8) ◽  
pp. 794-803 ◽  
Author(s):  
Heather M. Young ◽  
Sheeja George ◽  
Dario F. Narváez ◽  
Pratibha Srivastava ◽  
Andrew C. Schuerger ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Height ◽  
Epicuticular Wax ◽  
Soybean Rust ◽  
Disease Development ◽  
Area Index ◽  
Detached Leaf

Soybean rust (SBR), caused by Phakopsora pachyrhizi, is a damaging fungal disease of soybean (Glycine max). Although solar radiation can reduce SBR urediniospore survival, limited information is available on how solar radiation affects SBR progress within soybean canopies. Such information can aid in developing accurate SBR prediction models. To manipulate light penetration into soybean canopies, structures of shade cloth attenuating 30, 40, and 60% sunlight were constructed over soybean plots. In each plot, weekly evaluations of severity in lower, middle, and upper canopies, and daily temperature and relative humidity were recorded. Final plant height and leaf area index were also recorded for each plot. The correlation between amount of epicuticular wax and susceptibility of leaves in the lower, middle, and upper canopies was assessed with a detached leaf assay. Final disease severity was 46 to 150% greater in the lower canopy of all plots and in the middle canopy of 40 and 60% shaded plots. While daytime temperature within the canopy of nonshaded soybean was greater than shaded soybean by 2 to 3°C, temperatures recorded throughout typical evenings and mornings of the growing season in all treatments were within the range (10 to 28.5°C) for SBR development as was relative humidity. This indicates temperature and relative humidity were not limiting factors in this experiment. Epicuticular wax and disease severity in detached leaf assays from the upper canopy had significant negative correlation (P = 0.009, R = –0.84) regardless of shade treatment. In laboratory experiments, increasing simulated total solar radiation (UVA, UVB, and PAR) from 0.15 to 11.66 MJ m–2 increased mortality of urediniospores from 2 to 91%. Variability in disease development across canopy heights in early planted soybean may be attributed to the effects of solar radiation not only on urediniospore viability, but also on plant height, leaf area index, and epicuticular wax, which influence disease development of SBR. These results provide an understanding of the effect solar radiation has on the progression of SBR within the soybean canopy.

scholarly journals Effect of rate and method of phosphorus application on the growth and development of 'Pasja' crops

2009 ◽  
pp. 101-106 ◽  
Author(s):  
E. Chakwizira ◽  
D.J. Moot ◽  
W.R. Scott ◽  
A. Fletcher
Keyword(s):  
Solar Radiation ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Growth And Development ◽  
Brassica Campestris ◽  
Silt Loam ◽  
Area Index ◽  
Olsen P ◽  
Loam Soil ◽  
Phosphorus Application

'Pasja' (Brassica campestris x napus) was grown at Lincoln in 2008, with banded or broadcast phosphorus (P) fertiliser applied at 0, 20, 40 or 60 kg/ha at establishment on a Templeton silt loam soil of moderate fertility (Olsen P of 9-17 mg/ kg range for individual plots). Keywords: Brassica campestris, critical leaf area index, DM accumulation, leaf area index, leaf to stem ratio, solar radiation

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