scholarly journals Evaluation of the INTERCOM model for predicting growth of forest herbs

2010 ◽  
Vol 62 (1) ◽  
pp. 175-183 ◽  
Author(s):  
Zorica Popovic ◽  
J.L. Lindquist

The ecophysiological model INTERCOM was evaluated for its suitability in predicting the growth of perennial forest herbs. A field experiment was conducted to obtain data on photosynthesis and growth parameters of two spring flowering understorey geophytes. Results were used to parameterize the model and its performance was evaluated using the average normalized difference (AE) between predicted and observed biomass and the leaf area index. The model was assumed to provide accurate simulations if the AE was smaller than 0.4. Adjusting the photosynthetic intensity parameters in the model to reflect observed changes in photosynthesis throughout the growing period resulted in the accurate prediction of Scilla bifolia and Arum maculatum biomass (AE=0.13 and AE=0.021, respectively) and LAI (AE=-0.16 and AE=-0.08, respectively). Ecophysiological models may be useful tools for predicting the biomass accumulation of forest understorey species in response to varying environmental conditions, which could be useful for monitoring forest ecosystem health.

Weed Science ◽  
1999 ◽  
Vol 47 (6) ◽  
pp. 712-719 ◽  
Author(s):  
Anne Légère ◽  
Yuguang Bai

The robustness of competitive attributes of cereals such as rapid and uniform seedling emergence, tillering, early biomass accumulation and canopy closure, and height advantage over weeds have not yet been tested under environmental conditions typical of no-till (NT) cropping systems. Our objective was to evaluate the effects or NT practices on growth and productivity ofAvena sativa, Triticum aestivum, Hordeum vulgare, and associated weeds. The experiment was conducted on a Kamouraska clay at La Pocatière, QC, in 1994, 1995, and 1996.Avena sativa, T. aestivum, andH. vulgarewere grown under tilled and NT practices. Cereal growth parameters were measured six (1994) or seven (1995) times between planting and the 11th week after planting but only once in 1996. Grain yields and yield components were determined at crop maturity.Avena sativaandH. vulgarepopulations were little affected by tillage, whereasT. aestivumpopulations were reduced by 16 to 20% in NT systems. Growth in height in NT systems was either similar or greater than in tilled systems in all three cereals. Cereal leaf area index (LAI) and biomass accumulation was also comparable between tillage systems, except forT. aestivumLAI in 1994, which was greater in tilled plots on two sampling dates. Response of annual dicots to tillage was inconsistent in all crops. Annual monocots dominated in some but not all NT systems. Perennial dicots dominated in NT systems, whereas perennial monocots were more abundant in tilled systems in all three cereals.Avena sativaandT. aestivumyields in NT plots were comparable or greater than in tilled plots, in spite of having either lower test weights (A. sativa) or lower 1,000-grain weights (T. aestivum). NTT. aestivumproductivity was maintained in spite of reduced plant establishment.Hordeum vulgareyields were also similar across tillage systems, except in 1995, when yields in tilled plots were greater than in NT plots. The height advantage observed for NTH. vulgaredid not result in improved yields. All three cereals, and particularlyA. sativa, appeared well suited to NT systems, despite the pressure provided by different weed groups, compared to tilled systems. However, results suggest that NT production of cereals could benefit from improved attention to perennial dicot control and crop seedling establishment, particularly forT. aestivum.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 380
Author(s):  
Abdoul Kader Mounkaila Hamani ◽  
Jinsai Chen ◽  
Mukesh Kumar Soothar ◽  
Guangshuai Wang ◽  
Xiaojun Shen ◽  
...  

Soil salinization adversely affects agricultural productivity. Mitigating the adverse effects of salinity represents a current major challenge for agricultural researchers worldwide. The effects of exogenously applied glycine betaine (GB) and salicylic acid (SA) on mitigating sodium toxicity and improving the growth of cotton seedlings subjected to salt stress remain unclear. The treatments in a phytotron included a control (CK, exogenously untreated, non-saline), two NaCl conditions (0 and 150 mM), four exogenous GB concentrations (0, 2.5, 5.0, and 7.5 mM), and four exogenous SA concentrations (0, 1.0, 1.5, and 2.0 mM). The shoot and roots exposed to 150 mM NaCl without supplementation had significantly higher Na+ and reduced K+, Ca2+, and Mg2+ contents, along with lowered biomass, compared with those of CK. Under NaCl stress, exogenous GB and SA at all concentrations substantially inversed these trends by improving ion uptake regulation and biomass accumulation compared with NaCl stress alone. Supplementation with 5.0 mM GB and with 1.0 mM SA under NaCl stress were the most effective conditions for mitigating Na+ toxicity and enhancing biomass accumulation. NaCl stress had a negative effect on plant growth parameters, including plant height, leaf area, leaf water potential, and total nitrogen (N) in the shoot and roots, which were improved by supplementation with 5.0 mM GB or 1.0 mM SA. Supplementation with 5.0 mM exogenous GB was more effective in controlling the percentage loss of conductivity (PLC) under NaCl stress.


2021 ◽  
Vol 128 ◽  
pp. 107841
Author(s):  
Jan-Peter George ◽  
Wei Yang ◽  
Hideki Kobayashi ◽  
Tobias Biermann ◽  
Arnaud Carrara ◽  
...  

2021 ◽  
Vol 34 (1) ◽  
pp. 69-79
Author(s):  
Deepali Nagre ◽  
Roseline Xalxo ◽  
Vibhuti Chandrakar ◽  
S. Keshavkant

The ability of melatonin to regulate number of physiological and biochemical processes under different environmental stresses has been widely studied in plants. So, this investigation was done to study the protective roles of melatonin on Cicer arietinum L. grown under arsenic stress. Subjecting Cicer arietinum L. seeds to arsenic stress caused significant decreases in germination percentage, radicle growth, biomass accumulation, protein content and activities of antioxidant enzymes. On the other hand, melatonin treatment significantly increased growth parameters and protein quantity via improving antioxidant enzyme systems as compared with their corresponding untreated controls.


Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1305 ◽  
Author(s):  
Xin Han ◽  
Zheng Wei ◽  
Baozhong Zhang ◽  
Congying Han ◽  
Jianzheng Song

The adjustment of crop planting structure can change the process of water and material circulation, and thus affect the total amount of water and evapotranspiration in the irrigation district. To guide the allocation of water resources in the region, it is beneficial to ascertain the effects of changing the crop planting structure on water saving and farmland water productivity in the irrigation district. This paper takes Yingke Irrigation District as the background. According to the continuous observation data from 2012 to 2013, Based on the modified Soil and Water Assessment Tool (SWAT) model and taking advantage of monthly scale remote sensing EvapoTranspiration (ET) and crop growth parameters (leaf area index and shoot dry matter), we tested the simulation accuracy of the model, proposed irrigation efficiency calculation methods considering water drainage, and established the scenario analysis method for the spatial distribution of crop planting structure. Finally, we evaluated the changes in water savings in irrigation district projects and resources, the irrigation water productivity and the net income water productivity under different planting structure scenarios. The results indicate that the efficiency of irrigation has increased by 15~20%, while considering drainage, as compared with conventional irrigation efficiency. Additionally, the adjustment of crop planting structure can reduce regional evapotranspiration by 14.9%, reduce the regional irrigation volume by 30%, and increase the net income of each regional water area by 16%.


MAUSAM ◽  
2022 ◽  
Vol 53 (1) ◽  
pp. 57-62
Author(s):  
RAJ SINGH ◽  
V. U. M. RAO ◽  
DIWAN SINGH

Field experiment was conducted for two crop seasons (1996-97 & 1997-98) at CCS, HAU, Hisar research farm to study the effect of weather parameters on growth and yield of mustard. The results indicated that an increase in maximum temperature and duration of sunshine hours resulted in increased leaf area index (LAI). The increase in daytime temperature resulted in higher biomass accumulation during vegetative phase, but the trend was reversed during physiological maturity. The biomass accumulation in brassicas increased with increase in evaporation rate during the grand growth period. However, latter on during the physiological maturity, increase in evaporation rate resulted in decline of biomass accumulation. Further, it was noted that the magnitudes of some important weather parameters (maximum and minimum temperatures, pan evaporation and morning relative humidity) during the vegetative phase of crop played decisive role in deciding the quantum of seed yield which is a resultant of various yield attributes. The rainfall during the crop growing season either have no association or had a negative relationship with yield and yield attributes because crop never experienced water stress as abundant moisture was made available through irrigation.


Author(s):  
Y. Rajasekhara Reddy ◽  
G. Ramanandam ◽  
P. Subbaramamma ◽  
A. V. D. Dorajeerao

A field experiment was carried out during rabi season of 2018-2019, at college farm, College of Horticulture, Dr. Y.S.R. Horticultural University, Venkataramannagudem, West Godavari District, Andhra Pradesh. The experiment was laidout in a Randomised Block Design with eleven treatments (viz., T1- NAA @ 50 ppm, T2-NAA @ 100 ppm, T3-GA3 @ 50 ppm,  T4-GA3 @ 100 ppm, T5-Thiourea @ 250 ppm, T6-Thiourea @ 500 ppm, T7-28-Homobrassinolide @ 0.1 ppm, T8-28-Homobrassinolide @ 0.2 ppm, T9-Triacontinol @ 2.5 ppm, T10-Triacontinol @ 5 ppm, T11-(Control) Water spray) and three replications. The treatments were imposed at 30 and 45 DAT in the form of foliar spray. Foliar application of GA3@ 100 ppm (T4) had recorded the maximum plant height (108.20 cm), leaf area (9.53 cm2) and leaf area index (0.74). Foliar application of thiourea @ 250 ppm (T5) had recorded the maximum values with respect to number of primary branches (15.03 plant-1), number of secondary branches (83.40 plant-1), plant spread (1793 cm2 plant-1), fresh weight (376.29 g plant-1), dry weight (103.54 g plant-1) and number of leaves plant-1((298.8). The same treatment (T5) had recorded the highest values with respect to crop growth rate (1.44 gm-2d-1), chlorophyll-a (1.40 mg g-1), chlorophyll-b (0.076 mg g-1) and total chlorophyll contents (1.48 mg g-1) in the leaves.


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