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Assessment of Effects of Agricultura...

Thapa, Arjun,

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Assessment of Effects of Agricultural Conservation Practices at the Field and Watershed Scales: Measurement and Modeling /

Record Type:	Electronic resources : Monograph/item
Title/Author:	Assessment of Effects of Agricultural Conservation Practices at the Field and Watershed Scales: Measurement and Modeling // Arjun Thapa.
Author:	Thapa, Arjun,
Description:	1 electronic resource (277 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 86-12, Section: B.
Contained By:	Dissertations Abstracts International86-12B.
Subject:	Natural resource management. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31938880
ISBN:	9798280757240

Assessment of Effects of Agricultural Conservation Practices at the Field and Watershed Scales: Measurement and Modeling /
Thapa, Arjun,

Assessment of Effects of Agricultural Conservation Practices at the Field and Watershed Scales: Measurement and Modeling /Arjun Thapa. - 1 electronic resource (277 pages)

Source: Dissertations Abstracts International, Volume: 86-12, Section: B.

Healthy freshwater resources are essential for both human and ecosystem well-being. Maintaining the quality of water bodies in a fresh and pristine condition requires that surface runoff, which feeds into these water bodies, remains free from pollutants. However, intensive agricultural activities to increase crop production to meet global food demand have significantly contributed to sediment and nutrient pollution in freshwater ecosystems. Reducing agricultural pollution at the source is critical for protecting the freshwater ecosystem and preserving soil health and nutrients for long-term productivity. To achieve this goal, mapping agricultural pollutants from the agricultural field and watershed, particularly in the presence and absence of conservation practices, is vital. The objective of the study was to map the daily pollutant loads from a pair of 7.83 ha commercial cotton fields as well as a small watershed to study the effects of conservation practices - filter strips and cover crops - using process-based APEX (Agricultural Policy Environmental eXtender) model and data-driven machine learning models. Of the two paired fields located at Little River Ditches Watershed in northeastern Arkansas, we implemented cover crops in-field during the fallow season and filter strips at the edge-of-field during the crop-growing season in the treatment field only but not in the control field. The results from monitoring of the runoff from the two fields found that cover crops significantly reduced median peak flow and sediment load by 49% and 43%, respectively. Similarly, filter strips effectively reduced runoff by 36%, peak flow by 49%, sediment load by 46%, total phosphorus by 4%, and total nitrogen by 7%, on average. Additionally, the APEX model and nine machine-learning models were employed to simulate pollutant loads with and without these conservation practices in these fields. The APEX model simulations indicated that cover crop and filter strips treatment significantly reduced runoff, sediment, total phosphorus, and total nitrogen by 41%, 56%, 64%, and 57%, respectively. Furthermore, measured and APEX model simulation results demonstrated no significant difference in cotton yield due to cover crops. Machine learning model predictions further verified that cover crops and filter strips reduced runoff by 33%, sediment by 46%, total phosphorus by 47%, and total nitrogen by 44%. This study showed that the performance statistics of advanced machine learning models such as LSTM, CNN, and hybrid models outperformed conventional machine models, which usually experienced overfitting problems.Water quantity and quality data were also measured daily from a 53.78 km² (5378 ha) Little River Ditches Watershed, a predominantly agricultural watershed in northeastern Arkansas. The ArcAPEX model was used to simulate the runoff, sediment, and nutrient loads in the watershed. Scenario-based ArcAPEX simulations showed that implementing cover crops and filter strips in 30% of the watershed area could reduce runoff by 5%, sediment by 26%, total phosphorus by 22%, and total nitrogen by 19%. The measured and simulated results from the field and watershed demonstrated that conservation practices such as cover crops and filter strips can effectively reduce pollutant load without negatively impacting crop yields. These findings highlight the importance of integrating conservation practices into agricultural management to enhance runoff water quality while maintaining sustainable crop production.

English

ISBN: 9798280757240Subjects--Topical Terms:

589570
Natural resource management.
Subjects--Index Terms:

Agricultural Policy Environmental eXtender

Assessment of Effects of Agricultural Conservation Practices at the Field and Watershed Scales: Measurement and Modeling /
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245 1 0 $a Assessment of Effects of Agricultural Conservation Practices at the Field and Watershed Scales: Measurement and Modeling / $c Arjun Thapa.
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300 $a 1 electronic resource (277 pages)
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500 $a Source: Dissertations Abstracts International, Volume: 86-12, Section: B.
500 $a Advisors: Aryal, Niroj Committee members: Reba, Michele L.; Jha, Manoj Kumar; Masasi, Blessing; Gaire, Sunil Kumar.
502 $b Ph.D. $c North Carolina Agricultural and Technical State University $d 2025.
520 $a Healthy freshwater resources are essential for both human and ecosystem well-being. Maintaining the quality of water bodies in a fresh and pristine condition requires that surface runoff, which feeds into these water bodies, remains free from pollutants. However, intensive agricultural activities to increase crop production to meet global food demand have significantly contributed to sediment and nutrient pollution in freshwater ecosystems. Reducing agricultural pollution at the source is critical for protecting the freshwater ecosystem and preserving soil health and nutrients for long-term productivity. To achieve this goal, mapping agricultural pollutants from the agricultural field and watershed, particularly in the presence and absence of conservation practices, is vital. The objective of the study was to map the daily pollutant loads from a pair of 7.83 ha commercial cotton fields as well as a small watershed to study the effects of conservation practices - filter strips and cover crops - using process-based APEX (Agricultural Policy Environmental eXtender) model and data-driven machine learning models. Of the two paired fields located at Little River Ditches Watershed in northeastern Arkansas, we implemented cover crops in-field during the fallow season and filter strips at the edge-of-field during the crop-growing season in the treatment field only but not in the control field. The results from monitoring of the runoff from the two fields found that cover crops significantly reduced median peak flow and sediment load by 49% and 43%, respectively. Similarly, filter strips effectively reduced runoff by 36%, peak flow by 49%, sediment load by 46%, total phosphorus by 4%, and total nitrogen by 7%, on average. Additionally, the APEX model and nine machine-learning models were employed to simulate pollutant loads with and without these conservation practices in these fields. The APEX model simulations indicated that cover crop and filter strips treatment significantly reduced runoff, sediment, total phosphorus, and total nitrogen by 41%, 56%, 64%, and 57%, respectively. Furthermore, measured and APEX model simulation results demonstrated no significant difference in cotton yield due to cover crops. Machine learning model predictions further verified that cover crops and filter strips reduced runoff by 33%, sediment by 46%, total phosphorus by 47%, and total nitrogen by 44%. This study showed that the performance statistics of advanced machine learning models such as LSTM, CNN, and hybrid models outperformed conventional machine models, which usually experienced overfitting problems.Water quantity and quality data were also measured daily from a 53.78 km² (5378 ha) Little River Ditches Watershed, a predominantly agricultural watershed in northeastern Arkansas. The ArcAPEX model was used to simulate the runoff, sediment, and nutrient loads in the watershed. Scenario-based ArcAPEX simulations showed that implementing cover crops and filter strips in 30% of the watershed area could reduce runoff by 5%, sediment by 26%, total phosphorus by 22%, and total nitrogen by 19%. The measured and simulated results from the field and watershed demonstrated that conservation practices such as cover crops and filter strips can effectively reduce pollutant load without negatively impacting crop yields. These findings highlight the importance of integrating conservation practices into agricultural management to enhance runoff water quality while maintaining sustainable crop production.
546 $a English
590 $a School code: 1544
650 4 $a Natural resource management. $3 589570
650 4 $a Agronomy. $3 2122783
650 4 $a Agriculture. $3 518588
650 4 $a Conservation biology. $3 535736
650 4 $a Water resources management. $3 794747
653 $a Agricultural Policy Environmental eXtender
653 $a Cotton crop
653 $a Cover crops
653 $a Edge-of-field monitoring
653 $a Filter strips
653 $a Machine learning models
690 $a 0528
690 $a 0408
690 $a 0473
690 $a 0595
690 $a 0285
710 2 $a North Carolina Agricultural and Technical State University. $b Agricultural and Environmental Sciences. $e degree granting institution. $3 3825842
720 1 $a Aryal, Niroj $e degree supervisor.
773 0 $t Dissertations Abstracts International $g 86-12B.
790 $a 1544
791 $a Ph.D.
792 $a 2025
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31938880