scholarly journals Use of PhenoCam Measurements and Image Analysis to Inform the ALMANAC Process-based Simulation Model

Author(s):  
Jacqueline Jacot ◽  
James R. Kiniry ◽  
Amber S. Williams ◽  
Addison Coronel ◽  
Jianzhong Su ◽  
...  

Near-surface remote sensing has been used to document seasonal growth patterns (i.e. phenology) for plant communities in diverse habitats. Phenology from this source may only apply to the area within the images. Meanwhile ecosystem models can accommodate variable weather and landscape differences to plant growth, but accuracy is improved by adding ground-truthed inputs. The objective of this study was to use PhenoCam data, image analysis, and Beer’s law with established extinction coefficients to compare leaf area index (LAI) development in the ALMANAC model for diverse plant types and environments. Results indicate that PhenoCam time series imagery can be used to improve leaf area development in ALMANAC by adjusting parameter values to better match LAI derived values in new diverse environments. Soybeans, mesquite, and maize produced the most successful match between the model simulations and PhenoCam data out of the eight species simulated. This study represents, to our knowledge, the first independent evaluation of the ALMANAC process-based plant growth model with imagery in agroecosystems available from the PhenoCam network. The results show how PhenoCam data can make a valuable contribution to validate process-based models, making these models much more realistic and allows for expansion of PhenoCam influence.

1965 ◽  
Vol 57 (1) ◽  
pp. 61-64 ◽  
Author(s):  
D. A. Ashley ◽  
B. D. Doss ◽  
O. L. Bennett

1972 ◽  
Vol 12 (55) ◽  
pp. 216 ◽  
Author(s):  
DW Turner

The quantitative aspects of banana plant growth (omitting roots) at Alstonville, New South Wales, are described. Dry matter distribution, leaf area index (L), net assimilation rate (E), leaf area ratio (F) and relative growth rates (R), were measured. For a spring planting, only 1695 kg ha-l dry matter were produced in the first twelve months but 6780 kg were produced in the first half of the second year as the bunch and first ratoon crop developed. The plant crop was characterized by early leaf growth (high F) whereas in the ratoon crops, corm growth was a feature of early growth stages. Leaf area index was less than 1 for the first twelve months but reached 5 after 18 months. Plants were 3.1 m X 1.9 m apart. Net assimilation rate was affected by internal and external factors. The main internal control was the growth of suckers, which tended to increase E. Removal of the suckers in autumn or winter caused a sudden drop i i ~ E and absolute growth rate but when they were removed in early summer E was increased. The external controls affecting E were solar radiation, temperature and soil moisture, although the amount of variation explained in correlations was low. - R appeared to be constant in the plant crop within morphologically defined growth stages. This was not so in moon crops and R was probably a resultant of ontogenetic and climatic drifts. Desuckering in autumn and winter decreased R. Early summer desuckering increased R.


HortScience ◽  
2006 ◽  
Vol 41 (2) ◽  
pp. 361-366 ◽  
Author(s):  
Laurie Hodges ◽  
Entin Daningsih ◽  
James R. Brandle

Field experiments were conducted over 4 years to evaluate the effects of antitranspirant (Folicote, Aquatrol Inc., Paulsboro, N.J.) and polyacrylamide gel (SuperSorb, Aquatrol Inc., Paulsboro, N.J.) on early growth of transplanted muskmelon grown either protected by tree windbreaks or exposed to seasonal winds. A randomized complete block design (RCBD) with split plot arrangement was used with wind protection (sheltered and exposed) areas as the main treatment and use of an antitranspirant spray or gel dip as subtreatments. Based on destructive harvests in the field, treatments and subtreatments did not affect dry weight or leaf area index in the first 2 years. Specific contrasts, however, showed that gel application significantly increased fresh weight, dry weight, and leaf area index over that of the untreated transplants whereas the spray application tended to reduce these factors during the first 3 weeks after transplanting. Significant differences between gel and spray subtreatments disappeared by 5 weeks after transplanting. Shelterbelts ameliorated crop microclimate thereby enhancing plant growth. Significantly, wind velocity at canopy height was reduced 40% on average and soil temperatures were about 4% warmer in the sheltered plots compared to the exposed plots during the first 5 weeks post-transplant. Muskmelon plants in the sheltered areas grew significantly faster than the plants in the exposed areas in 2 of the 3 years reported, with the 3-year average fresh weight increased by 168% due to wind protection. Overall transplanting success and early growth were enhanced the most by wind protection, followed by the polyacrylamide gel root dip, and least by the antitranspirant foliar spray. We conclude that microclimate modification by wind speed reduction can increase early muskmelon plant growth more consistently than the use of polyacrylamide gel as a root dip at transplanting or the use of an antitranspirant spray. A polyacrylamide gel root dip generally will provide more benefit during early muskmelon growth than the use of an antitranspirant spray.


2020 ◽  
Vol 49 (2) ◽  
pp. 223-228
Author(s):  
R Sivakumar ◽  
K Krishna Surendar

Impact of plant growth regulators viz., benzyl amino purine (BAP - 50 ppm), brassinolide (BL - 0.5 ppm), and nutrient like KCl (1%) alone and with combination on growth and growth analytical parameters, and yield of finger millet by foliar spray at panicle initiation stage under rainfed condition was studied in field experiment. The treatments including control, KCl, BAP, BL, KCl + BAP, KCl + BL, BAP + BL and KCl + BAP + BL and different growth and growth analytical parameters were estimated. Combination of KCl, BAP and BL registered highest root length (17.2 cm), leaf area (425.3 cm2), leaf area index (1.82) and leaf area duration (55.7 days) compared to other treatments. Higher specific leaf weight and crop growth rate were recorded by KCl + BAP, and BAP + BL, respectively. The highest grain yield of 22.5 Q/ha was recorded by KCl + BAP + BL.


2014 ◽  
Vol 153 (8) ◽  
pp. 1449-1463 ◽  
Author(s):  
S. C. DA SILVA ◽  
L. E. T. PEREIRA ◽  
A. F. SBRISSIA ◽  
A. HERNANDEZ-GARAY

SUMMARYPlant organic reserves and sward leaf area index (LAI) influence plant growth, persistency and herbage accumulation in grazed swards. The present study was conducted to describe patterns of variation in herbage accumulation and carbohydrate and nitrogen (N) reserves in shoot and root of marandu palisade grass subjected to intensities of continuous stocking management throughout the year. Treatments corresponded to four levels of grazing intensity – severe (S), severe/moderate (S/M), moderate (M) and lenient (L) – and were implemented in the field using bands of sward surface height (SSH – 10, 20, 30 and 40 cm ± 10%, respectively) maintained through continuous stocking and variable stocking rate. Total N concentration was higher in the shoot relative to the root compartment during autumn, early and late spring. On the other hand, the concentration of non-structural carbohydrates (NSC) and soluble N was higher in the root compartment, regardless of grazing intensity and season of the year. When taking into account the pool of C and N reserves, the shoot compartment represented the main storage organ, since it corresponded to the largest pool of NSC (averages of 0·102 ± 0·0038 and 0·201 ± 0·0088 kg/m2 for root and shoot, respectively) and soluble N (averages of 2·7 ± 0·26 and 5·3 ± 0·59 kg/m2 for root and shoot, respectively). During late spring, the time of active plant growth, there was a clear contrast in herbage accumulation and sward LAI among grazing intensities, particularly between the severe and lenient grazing treatments. The results show that even with larger pools of soluble N and NSC in the shoot compartment, herbage accumulation was limited by the reduced leaf area of swards subjected to the severe grazing treatment, indicating that under continuous stocking growth seems to be sustained by current assimilates instead of organic reserves. Therefore, targets of grazing management for maximizing herbage accumulation throughout the year should provide adequate combinations between quantity and quality of sward leaf area. This condition was obtained in the severe/moderate and moderate grazing intensities, and corresponded to sward heights between 20 and 30 cm for marandu palisade grass.


2015 ◽  
Vol 1 (2) ◽  
pp. 17-20 ◽  
Author(s):  
Melika Taheri ◽  
Hania Ataiei Qarache ◽  
Alimohammad Ataei Qarache ◽  
Mahdieh Yoosefi

Nanoparticles are widely used in various fields like medicine and agriculture. Plant growth is hindered in mineral poor soils. Supplementing mineral poor soils can improve plant growth. One role of nanoparticles in agriculture is stimulating crop growth. In this study, the three different physical forms of ZnO particles in irrigation water were used to supplement mineral poor soil. Their effect on the growth of single cross 704 (SC704) corn was investigated. We studied the effects of ZnO nanocolloid, ZnO nanoparticles, and micrometric ZnO particles. The concentration of nanoparticles in irrigation water was 2 ppm. The results show that the addition of all three ZnO particle types in irrigation water improved shoot dry matter and leaf area index. The best results came from the ZnO nanoparticle treatment which on average, increased the shoot dry matter and leaf area indexes by 63.8% and 69.7% respectively. Based on these results, we can conclude that zinc nanoparticles can improve corn growth and yield in mineral poor soils.


2007 ◽  
Vol 20 (6) ◽  
pp. 993-1015 ◽  
Author(s):  
Hyun-Suk Kang ◽  
Yongkang Xue ◽  
G. James Collatz

Abstract This study assesses the impact of two different remote sensing–derived leaf area index (RSLAI) datasets retrieved from the same source (i.e., Advanced Very High Resolution Radiometer measurements) on a general circulation model’s (GCM) seasonal climate simulations as well as the mechanisms that lead to the improvement in simulations over several regions. Based on the analysis of these two RSLAI datasets for 17 yr from 1982 to 1998, their spatial distribution patterns and characteristics are discussed. Despite some disagreements in the RSLAI magnitudes and the temporal variability between these two datasets over some areas, their effects on the simulation of near-surface climate and the regions with significant impact are generally similar to each other. Major disagreements in the simulated climate appear in a few limited regions. The GCM experiment using the RSLAI and other satellite-derived land surface products showed substantial improvements in the near-surface climate in the East Asian and West African summer monsoon areas and boreal forests of North America compared to the control experiment that used LAI extrapolated from limited ground surveys. For the East Asia and northwest U.S. regions, the major role of RSLAI changes is in partitioning the net radiative energy into latent and sensible heat fluxes, which results in discernable warming and decrease of precipitation due to the smaller RSLAI values compared to the control. Meanwhile, for the West African semiarid regions, where the LAI difference between RSLAI and control experiments is negligible, the decrease in surface albedo caused by the high vegetation cover fraction in the satellite-derived dataset plays an important role in altering local circulation that produces a positive feedback in land/atmosphere interaction.


Author(s):  
BR Chaudhary ◽  
MD Sharma ◽  
SM Shakya ◽  
DM Gautam

The present investigation was carried out in the plain areas of Chitwan to determine the promising plant growth regulators (PGR) promoting growth and yield of chilli cultivars Jwala and Suryamukhi during winter-summer season of 2003/2004. Suryamukhi ranked superior to Jwala for most of the yield attributing characters, whereas Jwala was better in vegetative characters than Suryamukhi. Among PGRs, 2,4-D at 2 ppm was better for fruit set, number of fruits per plant, fruit length, number of seeds per fruit, seed weight per fruits, 1000 seed weight and fruit yield where as NAA at 40 ppm gave the highest leaf area index (LAI). PGRs were ineffective in promoting flowering and fruiting during winter season. GA3 at 10 ppm exhibited maximum amount of ascorbic acid content. The treatments, 2 ppm 2,4-D, 5 ppm triacontanol, 40 ppm NAA and 10 ppm GA3 produced 28.75%, 25.70%, 13.61% and 2.30% higher fruit yield over control, respectively. The highest net profit and B:C ratio were recorded in case of 2 ppm 2,4-D. The use of GA3 as foliar spray was not economical. Key words: 2,4-D, NAA, triacontanol, GA3, leaf area index, net profit, B:C ratio J. Inst. Agric. Anim. Sci. 27:65-68 (2006)


2020 ◽  
Vol 69 (3) ◽  
pp. 281-298
Author(s):  
József Dezső ◽  
Dénes Lóczy ◽  
Marietta Rezsek ◽  
Roman Hüppi ◽  
János Werner ◽  
...  

A more resilient adaptation to changing climate calls for crop diversification in vineyards, too. As a contribution to the H2020 collaborative project of the European Union, called Diverfarming, and part of the agroecological experiments during 2018 and 2019, grapevine biomass growth was monitored in connection with carbon storage types in soil and in the deposits removed by soil erosion. Phenometry was carried out interpreting segmented images to follow changes in biomass. It was found that crop growth could be best described by the Richards growth function. The distinction between grapevine and intercrop growth, however, requires further refinement in image analysis. In the laboratory TOC and Ntotal were measured for both the soil and the plant organs as well as for the eroded sediments. Greenhouse gas emissions and photosynthesis were monitored. Looking at the change of Leaf Area Index (LAI) over the growing period, image analysis pointed out the role of cut shoots from pruning in the C and N cycles. Maximum leaf area (at ripening) for guyot cultivation technique was extimated at 7,840 m2 ha-1. Soil loss by erosion was established by sediment traps at the end of vinestock rows. The grain size distribution analysis led to the remarkable result that as erosion proceeded, the ratio of the sand fraction increased but remained within the range for the textural class of loam. Organic matter contents grew to 38 g kg-1. The rate of soil erosion is higher in ploughed than in grassed interrows by orders of magnitude.


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