scholarly journals Sugarcane leaf area index modeling under different soil water conditions

1997 ◽  
Vol 54 (spe) ◽  
pp. 39-44 ◽  
Author(s):  
D.A. Teruel ◽  
V. Barbieri ◽  
L.A. Ferraro Jr.
Keyword(s):  
Water Stress ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Growth Period ◽  
Plant Growth And Development ◽  
Area Index ◽  
Stress Levels ◽  
Crop Cycle ◽  
Soil Water Conditions ◽  
Growth Deficit

The knowledge of the Leaf Area Index (LAI) variation during the whole crop cycle is essential to the modeling of the plant growth and development and, consequently, of the crop yield. Sugarcane LAI evolution models were developed for different crop cycles, by adjusting observed LAI values and growing degree-days summation data on a power-exponential function. The resultant equations simulate adequately the LAI behavior during the entire crop cycle. The effect of different water stress levels was calculated in different growth periods, upon the LAI growth The LAI growth deficit was correlated with the ratio between actual evapotranspiration and máximum evapotranspiration, and a constant named kuu was obtained hi each situation. It was noticed that the kLAI must be estimated not Just for different growth periods, but also for different water stress levels in each growth period.

Study on the applicability of leaf area index estimation model in an aspen forest over a growth period

2016 ◽  
Vol 36 (8) ◽  
Author(s):  
王龑 WANG Yan ◽  
田庆久 TIAN Qingjiu ◽  
王琦 WANG Qi ◽  
王磊 WANG Lei
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Growth Period ◽  
Estimation Model ◽  
Area Index ◽  
Aspen Forest ◽  
Index Estimation

scholarly journals Effects of vegetation structure on biomass accumulation in a Balanced Optimality Structure Vegetation Model (BOSVM v1.0)

2013 ◽  
Vol 6 (3) ◽  
pp. 4603-4663 ◽  
Author(s):  
Z. Yin ◽  
S. C. Dekker ◽  
B. J. J. M. van den Hurk ◽  
H. A. Dijkstra
Keyword(s):  
Water Stress ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Vegetation Structure ◽  
Bare Soil ◽  
Feedback Mechanism ◽  
Carbon Gain ◽  
Area Index ◽  
Local Climate ◽  
Vegetation Structures

Abstract. A myriad of interactions exist between vegetation and local climate for arid and semi-arid regions. Vegetation function, structure and individual behavior have large impacts on carbon-water-energy balances, which consequently influence local climate variability that, in turn, feeds back to the vegetation. In this study, a conceptual vegetation structure scheme is formulated and tested in a new carbon-water-energy coupled model to explore the importance of vegetation structure and vegetation adaptation to water stress on equilibrium biomass states. Surface energy, water and carbon fluxes are simulated for a range of vegetation structures across a precipitation gradient in West Africa and optimal vegetation structures that maximizes biomass for each precipitation regime are determined. Two different strategies of vegetation adaptation to water stress are included. Under dry conditions vegetation tries to maximize the Water Use Efficiency and Leaf Area Index as it tries to maximize carbon gain. However, an important negative feedback mechanism is found as the vegetation also tries to minimize its cover to optimize the surrounding bare ground area from which water can be extracted, thereby forming patches of vertical vegetation. Under larger precipitation, a positive feedback mechanism is found in which vegetation tries to maximize its cover as it then can reduce water loss from bare soil while having maximum carbon gain due to a large Leaf Area Index. The competition between vegetation and bare soil determines a transition between a "survival" state to a "growing" state.

scholarly journals Prediction of leaf area index in eucalypt plantations: effects of water stress and temperature

1998 ◽  
Vol 18 (8-9) ◽  
pp. 521-528 ◽  
Author(s):  
M. Battaglia ◽  
M. L. Cherry ◽  
C. L. Beadle ◽  
P. J. Sands ◽  
A. Hingston
Keyword(s):  
Water Stress ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Area Index ◽  
Eucalypt Plantations

scholarly journals Spatio-temporal Index Based on Time Series of Leaf Area Index for Identifying Heavy Metal Stress in Rice under Complex Stressors

2020 ◽  
Vol 17 (7) ◽  
pp. 2265
Author(s):  
Yibo Tang ◽  
Meiling Liu ◽  
Xiangnan Liu ◽  
Ling Wu ◽  
Bingyu Zhao ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Time Series ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Heavy Metal Stress ◽  
Metal Stress ◽  
Growth Stages ◽  
Area Index ◽  
Temporal Features ◽  
Stress Levels

Crops under various types of stresses, such as stress caused by heavy metals, drought and pest/disease exhibit similar changes in physiological-biochemical parameters (e.g., leaf area index [LAI] and chlorophyll). Thus, differentiating between heavy metal stress and nonheavy metal stress presents a great challenge. However, different stressors in crops do cause variations in spatiotemporal characteristics. This study aims to develop a spatiotemporal index based on LAI time series to identify heavy metal stress under complex stressors on a regional scale. The experimental area is located in Zhuzhou City, Hunan Province. The situ measured data and Sentinel-2A images from 2017 and 2018 were collected. First, a series of LAI in rice growth stages was simulated based on the WOrld FOod STudies (WOFOST) model incorporated with Sentinel 2 images. Second, the local Moran’s I and dynamic time warping (DTW) of LAI were calculated. Third, a stress index based on spatial and temporal features (SIST) was established to assess heavy metal stress levels according to the spatial autocorrelation and temporal dissimilarity of LAI. Results revealed the following: (1) The DTW of LAI is a good indicator for distinguishing stress levels. Specifically, rice subjected to high stress levels exhibits high DTW values. (2) Rice under heavy metal stress is well correlated with high-high SIST clusters. (3) Rice plants subjected to high pollution are observed in the northwest of the study regions and rice under low heavy metal stress is found in the south. The results suggest that SIST based on a sensitive indicator of rice biochemical impairment can be used to accurately detect regional heavy metal stress in rice. Combining spatial-temporal features and spectral information appears to be a highly promising method for discriminating heavy metal stress from complex stressors.

scholarly journals Assessment of Leaf Area Index of Rice for a Growing Cycle Using Multi-Temporal C-Band PolSAR Datasets

2019 ◽  
Vol 11 (22) ◽  
pp. 2640 ◽  
Author(s):  
Ze He ◽  
Shihua Li ◽  
Yong Wang ◽  
Yueming Hu ◽  
Feixiang Chen
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Growth Period ◽  
Estimation Accuracy ◽  
Area Index ◽  
Acceptable Error ◽  
Lower Estimation ◽  
Wide Availability ◽  
Multi Temporal ◽  
Phenological Cycle

C-band polarimetric synthetic aperture radar (PolSAR) data has been previously explored for estimating the leaf area index (LAI) of rice. Although the rice-growing cycle was partially covered in most of the studies, details for each phenological phase need to be further characterized. Additionally, the selection and exploration of polarimetric parameters are not comprehensive. This study evaluates the potential of a set of polarimetric parameters derived from multi-temporal RADARSAT-2 datasets for rice LAI estimation. The relationships of rice LAI with backscattering coefficients and polarimetric decomposition parameters have been examined in a complete phenological cycle. Most polarimetric parameters had weak relationships (R2 < 0.30) with LAI at the transplanting, reproductive, and maturity phase. Stronger relationships (R2 > 0.50) were observed at the vegetative phase. HV/VV and RVI FD had significant relationships (R2 > 0.80) with rice LAI for the whole growth period. They were utilized to develop empirical models. The best LAI inversion performance (RMSE = 0.81) was obtained when RVI FD was used. The acceptable error demonstrated the possibility to use the decomposition parameters for rice LAI estimation. The HV/VV-based model had a slightly lower estimation accuracy (RMSE = 1.29) but can be a practical alternative considering the wide availability of dual-polarized datasets.

scholarly journals THE SENSITIVITY OF C-BAND HYBRID POLARIMETRIC RISAT-1 SAR DATA TO LEAF AREA INDEX OF PADDY CROP

2018 ◽  
Vol IV-5 ◽  
pp. 215-222
Author(s):  
H. S. Srivastava ◽  
T. Sivasankar ◽  
P. Patel
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Incidence Angle ◽  
Remote Sensing Data ◽  
Microwave Remote Sensing ◽  
Biophysical Parameters ◽  
Area Index ◽  
Crop Cycle ◽  
Paddy Crop ◽  
Active Microwave Remote Sensing

<p><strong>Abstract.</strong> Active microwave remote sensing data has become an important source to retrieve crop biophysical parameters due to its unique sensitivity towards geometrical, structural and dielectric properties of various crop components. The temporal variability of various crop biophysical parameters during crop cycle has significant impact on the overall crop yield. In this study, two RISAT-1 hybrid polarimetric temporal SAR datasets at &amp;sim;32&amp;deg; incidence angle were acquired during 2015 Kharif season. The in-situ leaf area index (LAI) values from seventeen paddy fields were measured in synchrony to the satellite passes during both the campaigns. Analysis observed the decreasing trend of backscattering coefficients (&amp;sigma;&amp;deg;<sub>RH</sub>, &amp;sigma;&amp;deg;<sub>RV</sub>) with increase in LAI. Results indicate that the sensitivity of hybrid polarimetric parameters towards LAI, also depends on the change in crop structure due to crop growth. This study investigate the sensitivity of backscattering coefficients (σ&amp;deg;<sub>RH</sub>, σ&amp;deg;<sub>RV</sub>) and polarimetric parameters (even bounce, odd bounce and volume component) generated from m-&amp;delta;, m-&amp;chi; and m-&amp;alpha; space decompositions towards LAI using empirical analysis. An increase of 0.16 in R<sup>2</sup> (from 0.63 to 0.79) clearly indicates that the polarimetric parameters (even bounce, odd bounce and volume component) are more sensitive to LAI of paddy crop than the backscattering coefficients (&amp;sigma;&amp;deg;<sub>RH</sub>, &amp;sigma;&amp;deg;<sub>RV</sub>). It has been identified that the combined use of backscattering coefficients as well as polarimetric parameters (even bounce, odd bounce and volume component) in the model, can significantly improve the accuracy of the LAI estimation.</p>

scholarly journals Spring planting favors yield of new Brazilian potato cultivar BRS F63 Camila

2019 ◽  
Vol 37 (4) ◽  
pp. 415-422
Author(s):  
Vlandiney Eschemback ◽  
Jackson Kawakami ◽  
Aline M Genú ◽  
Leonardo Z Anderle
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Growth Period ◽  
Planting Date ◽  
Yield Potential ◽  
Plant Management ◽  
Average Weight ◽  
Index Number ◽  
Area Index ◽  
The Third

ABSTRACT The objective of this work was to evaluate the effect of different planting dates on the morphological variables and yield of new potato cultivars. The treatments were three cultivars (Agata, BRS Clara and BRS F63 Camila) and three planting date (October, December and February), carried out in two crop years (2014/15 and 2015/16). Total and marketable yields, average mass of total and marketable tubers, growth period, leaf area index, number and dry weight of the tubers were evaluated. The first planting date resulted in higher yield than the third date. Cultivar BRS F63 Camila was the one with highest yield in this first planting date (47.4 t ha-1), due to greater number of tubers produced in relation to the other cultivars and to higher average tuber weight (166 g tuber-1) in relation to Agata (113 g tuber-1). In the second planting date, no difference in yield was observed among cultivars. In the third planting date, BRS Clara was the cultivar with highest yield (21.3 t ha-1), due mainly to higher average weight of tubers (105 g tuber-1) in relation to Agata (49 g tuber-1), a fact favored by the higher leaf area index and longer growth period of BRS Clara. Depending on the planting date, one should choose the cultivar that results in maximum yield potential, since it is a plant management with low cost and high yield impact. For the second planting date, any of the studied cultivars can be used.

scholarly journals Competitive Ability and Physiological Aspects of Single and Intercropped Arugula (Eruca sativa Miller)

2021 ◽  
Vol 9 (2) ◽  
pp. 505
Author(s):  
Caris Dos Santos Viana ◽  
Marcelo De Almeida Guimarães ◽  
Hozano De Souza Lemos Neto ◽  
ítalo Marlone Gomes Sampaio ◽  
Ana Régia Alves de Araújo Hendges ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Competitive Ratio ◽  
Competitive Ability ◽  
Block Design ◽  
Net Photosynthesis ◽  
Physiological Factors ◽  
Area Index ◽  
Compensation Ratio ◽  
Crop Cycle

The aim of this study was to evaluate the competitive ability and physiological aspects of arugula intercropped with different aromatic condiment species. The study was carried out at the Teaching Garden of the Federal University of Ceará, Brazil. A randomised complete block design was used, with four replications and seven treatments: T1 (single arugula), T2 (arugula intercropped with coriander), T3 (arugula and parsley), T4 (arugula and garlic chives), T5 (single coriander), T6 (parsley) and T7 (garlic chives). A physiological evaluation was made of the arugula only. Competitive ability was obtained by calculating the aggressivity index, simplified aggressivity, competitive ratio and compensation ratio. The leaf area index and specific leaf area were calculated. No difference was seen between the treatments with arugula for the physiological factors net photosynthesis, stomatal conductance, rate of transpiration and instant carboxylation efficiency under evaluation within each crop cycle, but there was a difference between the two cycles. The coriander showed the highest aggressivity index and competitive ratio, and was considered more competitive than the arugula, with a higher compensation ratio. As an intercrop, the arugula showed greater competitive ability than the parsley and garlic chives. The greatest leaf area and leaf area index in the arugula plants were seen when intercropped with coriander.

Sign in / Sign up

Export Citation Format

Share Document