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156 results on '"Galagedara, Lakshman"'

8. Effectiveness of wood ash and paper sludge as liming and nutrient sources for annual ryegrass grown in podzolic soils of Newfoundland.

Author

Javed, Bilal, Katanda, Yeukai, Nadeem, Muhammad, Wickremasinghe, Thilini, Farhain, Muhammad M., Thomas, Raymond, Galagedara, Lakshman, Guo, Xiaobin, and Cheema, Mumtaz

Subjects
WOOD ash, ITALIAN ryegrass, RYEGRASSES, PAPER mill waste, LIMING of soils, ACID soils
Abstract

The acidic soils of western Newfoundland require liming for successful production of most crops. Locally sourced paper mill waste wood ash (WA) and paper sludge (SL) have potential as cheaper alternatives to limestone (LIME). Two greenhouse experiments evaluated WA and SL as liming and soil conditioning amendments for annual ryegrass (Lolium multiflorum) production. At 55 days after seeding, soil pH in WA (6.2 and 6.3) and wood ash and paper sludge (WASL) (6.0 and 6.3) were not different from that in LIME (6.0 and 6.5) for Experiments 1 and 2, respectively. However, pH in SL was 0.4 and 0.3 points lower than in LIME. Compared to LIME, WA, SL, and WASL produced 31%–52% and 57%–74% greater biomass yield in Experiments 1 and 2, respectively. N uptake was greater in WA (60 and 129 kg N ha−1) and WASL (51 and 97 kg N ha−1) compared to LIME (40 and 85 kg N ha−1), in Experiments 1 and 2, respectively. SL did not differ from LIME in Experiment 1, but reduced N uptake by 57% in Experiment 2. The results show significant potential of WA as an alternative amendment for liming and yield improvement of annual ryegrass grown in NL podzolic soils. However, SL has limited potential due to the risk of increasing N immobilization and residual soil mineral N when growing conditions are limiting. Combining SL with WA or biochar seemed to alleviate these risks. Overall, the adoption of these amendments for field production systems warrants serious consideration, following supplemental field studies to determine optimal application rates and timing. Core Ideas: The podzolic soils of Newfoundland have low pH and fertility, hence require liming.Locally sourced wastes, such as paper mill wood ash (WA) and sludge (SL), could be used as liming and nutrient sources.WA was equivalent to limestone (LIME) in improving and sustaining optimal soil pH.WA produced 52% and 74% greater annual ryegrass yield than conventional LIME application in podzolic soils. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Current perspective on nutrient solution management strategies to improve the nutrient and water use efficiency in hydroponic systems.

Author

Fathidarehnijeh, Elham, Nadeem, Muhammad, Cheema, Mumtaz, Thomas, Raymond, Krishnapillai, Mano, and Galagedara, Lakshman

Subjects
HYDROPONICS, WATER efficiency, ELECTRICAL conductivity measurement, VEGETABLE farming
Abstract

Hydroponics, a soilless cultivation technique using nutrient solutions under controlled conditions, is used for growing vegetables, high-value crops, and flowers. It produces significantly higher yields compared to conventional agriculture despite its higher energy consumption. The success of a hydroponic system relies on the composition of the nutrient solution, which contains all the essential mineral elements necessary for optimal plant growth and high yield. This review delves into the discussion of enhancing nutrient solution management strategies across different hydroponic systems. The aim of this review is to discuss various techniques for monitoring nutrient solutions in order to improve nutrient use efficiency (NUE) and water use efficiency (WUE). The conventional approach of monitoring the hydroponic nutrient solution using electrical conductivity measurement may not provide precise information about ion concentrations, potentially resulting in poor yields or excessive fertilizer usage. To overcome these limitations, alternative management strategies have been developed to enable more accurate monitoring and efficient management. One such strategy is the nitrogen-based approach, where nitrogen concentration becomes the primary controlled element in the nutrient solution and leads to WUE and NUE development by prolonging nutrient solution recirculation. Furthermore, various methods have been devised to improve nutrient solution strategies. These include using ion-selective electrodes to measure individual ions in the hydroponic nutrient solution, using sensors to monitor substrate moisture content, estimating water requirements, and implementing programmed nutrient addition methods. In addition to introducing different management techniques to optimize hydroponic performance, this review provides a better understanding of hydroponic systems. [ABSTRACT FROM AUTHOR]

Published
2024
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15. Assessing the effects of land cover change in runoff processes with RHESSys: a case study in the Waterford River Watershed, Newfoundland and Labrador, Canada.

Author

Bautista, David and Galagedara, Lakshman

Subjects
RUNOFF, WATERSHEDS, CITIES & towns, LAND use, ECOSYSTEMS, LAND cover
Abstract

Copyright of Canadian Water Resources Journal / Revue Canadienne des Ressources Hydriques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2024
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24. Ground-Penetrating Radar and Electromagnetic Induction: Challenges and Opportunities in Agriculture

Author

Pathirana, Sashini, Lambot, Sébastien, Krishnapillai, Manokarajah, Cheema, Mumtaz, Smeaton, Christina, Galagedara, Lakshman, and UCL - SST/ELI/ELIE - Environmental Sciences

Subjects
General Earth and Planetary Sciences, electromagnetic induction, ground-penetrating radar, hydro-geophysics, precision agriculture, soil studies
Abstract

Information on the spatiotemporal variability of soil properties and states within the agricultural landscape is vital to identify management zones supporting precision agriculture (PA). Ground-penetrating radar (GPR) and electromagnetic induction (EMI) techniques have been applied to assess soil properties, states, processes, and their spatiotemporal variability. This paper reviews the fundamental operating principles of GPR and EMI, their applications in soil studies, advantages and disadvantages, and knowledge gaps leading to the identification of the difficulties in integrating these two techniques to complement each other in soil data studies. Compared to the traditional methods, GPR and EMI have advantages, such as the ability to take non-destructive repeated measurements, high resolution, being labor-saving, and having more extensive spatial coverage with geo-referenced data within agricultural landscapes. GPR has been widely used to estimate soil water content (SWC) and water dynamics, while EMI has broader applications such as estimating SWC, soil salinity, bulk density, etc. Additionally, GPR can map soil horizons, the groundwater table, and other anomalies. The prospects of GPR and EMI applications in soil studies need to focus on the potential integration of GPR and EMI to overcome the intrinsic limitations of each technique and enhance their applications to support PA. Future advancements in PA can be strengthened by estimating many soil properties, states, and hydrological processes simultaneously to delineate management zones and calculate optimal inputs in the agricultural landscape.

Published
2023

30. Multifrequency electromagnetic induction soil moisture characterization under different land uses in western Newfoundland.

Author

Mensah, Clinton, Yeukai Katanda, Krishnapillai, Mano, Cheema, Mumtaz, and Galagedara, Lakshman

Subjects
SOIL moisture, ELECTROMAGNETIC induction, LAND use, TIME-domain reflectometry, ELECTRIC conductivity
Abstract

Identifying and characterizing the spatial patterns in soil moisture variability under different land use conditions is crucial for agriculture, forestry, and civil and environmental engineering. Yet employing multifrequency (MF) electromagnetic induction (EMI) techniques to carry out this task is under-represented in boreal podzolic soils. This study (i) compared four frequencies (~2.8-80kHz) for shallow mapping of soil moisture measured with a time-domain reflectometry at 0-20 cm soil depth under three different land use conditions (agricultural land, field road, and a recently cleared natural forest), (ii) developed a relationship between apparent electrical conductivity (ECa) measured using multifrequency EMI (GEM-2) and soil moisture, and (iii) assessed the effectiveness of ECa as an auxiliary variable in predicting soil moisture variations under different land use conditions. The means of ECa measurements were calculated for the exact sampling location (ground truth data) in each land use condition at a research site, Pasadena, NL, Canada. Soil moisture-ECa linear regression models for the three land use conditions were only statistically significant for 38.3 kHz frequency and were further analyzed. Further statistical analysis revealed that ECa was primarily controlled by soil moisture for the three land use conditions, with the natural forest possessing the highest mean ECa and soil moisture. Geostatistical analysis revealed that cokriging ECa with less densely collected soil moisture improved the characterization accuracy of soil moisture variability across the different land use conditions. These results reveal the effectiveness of the georeferenced MF-EMI technique to rapidly assess intrafield soil moisture variability under different land uses. [ABSTRACT FROM AUTHOR]

Published
2023
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33. Ground penetrating radar observes forest hillslope soil trends in Pynn's Brook, Newfoundland, Canada

Author

Gates, Zachary X., Galagedara, Lakshman, and Ziegler, Susan

Subjects
New Brunswick -- Natural history, Soils -- Environmental aspects -- Properties, Forests and forestry -- Environmental aspects -- Canada, Ground penetrating radar -- Usage, Earth sciences
Abstract

Soil property measurements to determine carbon (C) stocks are traditionally collected using physical samples or excavation practices which rely on small scale interpretations for sitewide averages. Such methods are limited [...]

Published
2022

34. Data set showing the development of a hyperspectral imaging technique using LA-ICP-MS to determine the spatial distribution of nutrients in soil cores

Author

Zaeem, Muhammad, primary, Nadeem, Muhammad, additional, Pham, Thu Huong, additional, Ashiq, Waqar, additional, Ali, Waqas, additional, Gillani, Syed Shah Mohioudin, additional, Moise, Eric R.D., additional, Leier, Heather, additional, Kavanagh, Vanessa, additional, Galagedara, Lakshman, additional, Cheema, Mumtaz, additional, and Thomas, Raymond, additional

Published
2022
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35. Biochar applications to boreal podzol improve soil hydraulic properties and control nitrogen dynamics.

Author

Saha, Ratnajit, Thomas, Raymond, Hawboldt, Kelly, Nadeem, Muhammad, Cheema, Mumtaz, and Galagedara, Lakshman

Subjects
PODZOL, HYDRAULIC control systems, BIOCHAR, PORE size distribution, SOIL profiles, SOILS
Abstract

The study aimed to investigate the effects of biochar (BC) application on hydraulic properties and nitrogen (N) transport in a podzolic soil profile. Soil samples were collected from an agricultural research field in Pasadena, Newfoundland, Canada. The following three types of leaching columns were prepared: (i) topsoil, (ii) top and E-horizon soil, and (iii) mixed soil (2:1 ratio of topsoil and E-horizon soil). Granular biochar (GBC) and powder biochar (PBC) were mixed with soils at the rate of 0%, 1% and 2% (w/w). BC's morphological structure and pore size distribution were examined using a scanning electron microscope, and the specific surface area was assessed by the Brunauer−Emmett−Teller method. Soil physical and hydraulic properties (bulk density, porosity, field capacity (FC), permanent wilting point, plant available water (PAW)), leaching concentration of nitrate (NO3−) and ammonium (NH4+), and volume of leachate were measured through a total of 378 experiments under laboratory conditions. GBC and PBC showed hydrophobic and hydrophilic characteristics, respectively. With the 2% PBC amendment, porosity increased by 3%, FC by 10%, and PAW by 13% in the mixed soil and reduced NO3− leaching by 36% in top and E-horizon soil and NH4+ leaching by 72% in mixed soil. On the other hand, NO3− and NH4+ leaching was reduced by 26% and 33% in mixed soil when treated with 2% GBC. A 2% application rate for both BC (GBC and PBC) showed the best performance to enhance soil hydraulic properties and retain significant amounts of NO3− and NH4+ in the boreal podzol. [ABSTRACT FROM AUTHOR]

Published
2023
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40. Corn-Soybean Intercropping Improved the Nutritional Quality of Forage Cultivated on Podzols in Boreal Climate

Author

Zaeem, Muhammad, primary, Nadeem, Muhammad, additional, Pham, Thu Huong, additional, Ashiq, Waqar, additional, Ali, Waqas, additional, Gillani, Syed Shah Mohioudin, additional, Moise, Eric, additional, Elavarthi, Sathya, additional, Kavanagh, Vanessa, additional, Cheema, Mumtaz, additional, Galagedara, Lakshman, additional, and Thomas, Raymond, additional

Published
2021
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