Optimal nitrogen fertilizer decisions for rice farming in a cascaded tank system in Sri Lanka: An analysis using an integrated crop, hydro-nutrient and economic model

Kanthilanka, H.; Ramilan, Thiagarajah; Farquharson, R.J.; Weerahewa, Jeevika

doi:10.1016/j.agsy.2023.103628

Cited by 6 publications

(4 citation statements)

References 67 publications

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“…The possible environmental impact of the current cultivation pattern on the Mahakanumulla cascade is presented by Figures 6, 7. Following Kanthilanka's (2022) equations, given the nature of the dry zone soil and other external factors, the nitrate leaks and soil loss in this LHG-rich system are demonstrated here. Accordingly, about 6,662 tons of soil are removed from the system annually due to cultivation during the regular rainy season and about 34 tons of nitrates are leaked.…”

Section: Resultsmentioning

confidence: 97%

“…Soil loss was estimated using published soil loss estimations by various scientific studies (Table 9). The nitrate leaching amount was calculated using estimates from Kanthilanka (2022). Nitrate leaching at the field level for rice and maize during the Yala and Maha seasons for the varied rate of N application in LHG poorly-drained soil is as follows.…”

Section: Computation Of the Extent Of Environmental Degradationmentioning

confidence: 99%

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Resource-use efficiency and environmental sustainability in the village tank cascade systems in the dry zone of Sri Lanka: An assessment using a bio-economic model

Dayananda¹,

Weerahewa²,

Weerasooriya³

2023

Front. Sustain. Food Syst.

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IntroductionVillage tank cascade systems (VTCSs) were built in ancient Sri Lanka as autonomous and climate-resilient agro-ecological systems. This study examines crop choices, farming profitability, and environmental sustainability under alternative rainfall regimes and market interventions in the Mahakanumulla VTCS of the Anuradhapura district.MethodA bio-economic model was developed to represent farming activities in the VTCS for the 2018-19 Maha and 2019 Yala cultivation seasons with data gathered from secondary sources and a key informant survey. The objective function of the model was the maximization of profits from farming. Resource limits were set for four types of land (highlands and lowlands in the Maha and Yala seasons), two types of labor (hired and family), and twelve-monthly water constraints. Six different models were developed for the six sub-divisions of the VTCS, considering the water-management hierarchy of the system. The models were simulated under alternative rainfall regimes and market interventions. The optimal crop mixes, farm profits, and shadow prices of resources associated with the baseline scenarios were compared with those of the counterfactual scenarios.Results and discussionThis analysis clearly illustrated that water and labor are the key determinants of the system. Also, when 922 ha of lowlands and 205 ha of uplands were allocated per annum for crop cultivation under normal environmental conditions, the annual profitability of the VTCS was LKR 111 million. During drought periods, a sharp reduction in profits was observed in the Maha season. Year-round drought caused a 77% profit reduction compared to the baseline. The Maha drought alone caused a reduction of 47%. The introduction of a buy-back arrangement for chili and maize helped farmers to increase profits by 185 and 28%, respectively, under normal climate scenarios, turning to 954 and 5% during extreme drought scenarios, compared to the baseline. The least nitrate leaching and soil losses occurred in green chili cultivation. The introduction of market-based solutions is recommended to address extreme climate events experienced by the rural communities dependent on the VTCSs in Sri Lanka.

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Section: Resultsmentioning

confidence: 97%

Section: Computation Of the Extent Of Environmental Degradationmentioning

confidence: 99%

Resource-use efficiency and environmental sustainability in the village tank cascade systems in the dry zone of Sri Lanka: An assessment using a bio-economic model

Dayananda¹,

Weerahewa²,

Weerasooriya³

2023

Front. Sustain. Food Syst.

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“…Reducing chemical pollution is critical to maintain water quality. An over-reliance on agrochemicals and subsidised fertiliser has resulted in major impacts on the VTCS environments, particularly on water quality and soil health [122][123][124]. The diminishing surface and groundwater quality due to human activities, such as the excessive use of pesticides, fertiliser, detergents, and waste dumping, puts the sustainability of the system at risk [9,119,[125][126][127][128][129][130].…”

Section: Mapping Of Research Clustersmentioning

confidence: 99%

Sustainability and Productivity of Village Tank Cascade Systems: A Bibliometric Analysis and Knowledge Mapping

Ratnayake,

Reid,

Larder

et al. 2024

Sustainability

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Research on social–ecological systems is rapidly expanding globally in response to human-induced climate change, biodiversity loss, and ecosystem degradation. Safeguarding these traditional agroecosystems is vital according to the 2030 Agenda for Sustainable Development. In the last decade, there has been a growing research interest in the Village Tank Cascade Systems (VTCSs) of Sri Lanka, recognised as social–ecological systems. However, few studies have systematically analysed VTCS research in Sri Lanka. To examine this apparent knowledge gap in more detail, a bibliometric analysis and knowledge mapping were conducted to systematically analyse and interpret the state, trends, clusters, and emerging fields of VTCS research. In total, 159 peer-reviewed research publications between 1985 and 2023 were obtained from the Web of Science Core Collection, Scopus databases, Google Scholar, and ResearchGate to perform this analysis. Furthermore, this study employed the Sustainability Assessment of Food and Agriculture systems (SAFA) tool, developed by the Food and Agriculture Organization of the United Nations, to map the inclusion of sustainability and productivity dimensions in VTCS research, in alignment with the objectives set forth by the 2030 Agenda for Sustainable Development. The study provides insight into dominant and neglected areas of future VTCS research.

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“…In agriculture, the augmentation of soil fertility usually involves substantial fertilizer applications to bolster crop yields ( Brtnicky et al, 2023 ). However, the excessive reliance on chemical fertilizers has led to a range of environmental concerns, including biodiversity loss, soil acidification and degradation, greenhouse emissions, and contamination of ground and surface water systems ( Searchinger et al, 2018 ; Yu et al, 2020 ; Kanthilanka et al, 2023 ). To mitigate the adverse repercussions of chemical fertilizer application, organic fertilizers have emerged as a potential alternative strategy ( Chen et al, 2020 ; Kumari et al, 2024 ).…”

Section: Introductionmentioning

confidence: 99%

Synergistic effects of rhizosphere effect and combined organic and chemical fertilizers application on soil bacterial diversity and community structure in oilseed rape cultivation

Wang,

Qin,

Zhang

et al. 2024

Front. Microbiol.

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The combined application of chemical and organic fertilizers has been recognized to enhance soil fertility and foster the soil microbial ecosystem. However, the optimal ratio of chemical and organic fertilizers in oilseed rape cultivation is still uncertain, and the role of rhizosphere effect is still unclear. Thus, this study aimed to elucidate the impacts of varying ratios of chemical and organic fertilizers on the structure and potential functionalities of rhizosphere and non-rhizosphere soil microbial communities. The interplay of microbial communities with soil properties and oilseed rape root exudates was investigated in controlled pot cultivations receiving varying ratios of chemical and organic fertilizers. Results indicated clear segregation in the soil bacterial community, influenced by both fertilization treatments and rhizosphere effects. The bacterial community structure significantly correlated with nitrate nitrogen, organic acids, and dissolved organic carbon (DOC) content. Rhizosphere effects led to increased bacteria abundance, reduced diversity, and decreased network stability. Notably, F3 treatment receiving 25% chemical and 75% organic fertilizers showed a significantly higher abundance at 1.43 × 1011 copies g−1 dry soil, accompanied by increased species and genetic diversity, and ecological network complexity. This treatment also yielded the highest aboveground biomass of oilseed rape. However, the application of organic fertilizers also increased the risk of plant pathogenicity. This study reveals the impact of fertilizers and rhizosphere effects on soil microbial community structure and function, shedding light on the establishment of more effective fertilization schemes for oilseed rape agriculture.

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Optimal nitrogen fertilizer decisions for rice farming in a cascaded tank system in Sri Lanka: An analysis using an integrated crop, hydro-nutrient and economic model

Cited by 6 publications

References 67 publications

Resource-use efficiency and environmental sustainability in the village tank cascade systems in the dry zone of Sri Lanka: An assessment using a bio-economic model

Resource-use efficiency and environmental sustainability in the village tank cascade systems in the dry zone of Sri Lanka: An assessment using a bio-economic model

Sustainability and Productivity of Village Tank Cascade Systems: A Bibliometric Analysis and Knowledge Mapping

Synergistic effects of rhizosphere effect and combined organic and chemical fertilizers application on soil bacterial diversity and community structure in oilseed rape cultivation

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