Optimization of Croplands for Efficient and Sustainable Resource Use and Management

Maria Cristina Punay Pammit, Julieta A. Delos Reyes, Antonio Jesus A. Quilloy, Danesto B. Anacio

Abstract


The farmers in Ilocos Norte, Philippines, produce vegetable crops during the dry season (November to May). During this time, they face simultaneous climatic and resource challenges, which impact their production decisions and threaten food security. Land use decisions at the farm level require trade-offs due to resource constraints and other inherent factors, thus, informed decision-making is called for. This study determines the optimal cropland allocation where farmers can earn the highest income given their level of existing resources and production objectives during the dry season. Only prime agricultural lands were considered, and it excluded livestock production due to resource limitations and more sophisticated models and analytical software required. Production data from 80 farmers were subjected to optimization through linear programming in Microsoft Excel Solver. Results revealed that the farmers should adjust their current production level and cropland areas during the dry season to further maximize profit. Particularly, the farmer-respondents should devote 2.22-ha croplands to tomato production to earn 208.09 percent higher profit, and another 2.90-ha for purple corn and peanut production to generate 41 percent more profit than their existing crop production system. The study provides scientific evidence that maximum income can be attained if the farmers in the study areas change their existing crop production to the identified best alternative. It also offers information that could be a basis for crafting a decision tool for efficient and sustainable agricultural land use and management in the respective areas. Future studies may consider incorporating price volatility, risk preferences of farmers, crop rotation requirements, and non-linear yield responses. Analysis of wider agricultural lands combined with livestock production may also provide a more comprehensive perspective.


Keywords


Agricultural Land; Cropland Allocation; Linear Programming; Optimization; Sustainability

Full Text:

PDF

References


J. V. Silva, P. Reidsma, F. Baudron, A. G. Laborte, K. E. Giller, and M. K. van Ittersum, “How sustainable is sustainable intensification? Assessing yield gaps at field and farm level across the globe,” Global Food Security, November 2020. [Online]. Available: https://doi.org/10.1016/j.gfs.2021.100552.

K. E. Giller, et al., “Communicating complexity: integrated assessment of trade-offs concerning soil fertility management within African farming systems to support innovation and development,” Agricultural Systems. vol. 2, no. 104, pp. 191–203, February 2011. [Online]. Available: https://doi.org/10.1016/j.agsy.2010.07.002.

A. Mohammadzadeh, J. Vafabakhsh, A. M. Damghani, and R. Deihimfard, “Optimal land allocation to crop production in different decision priorities and water availability scenarios: East Azerbaijan province of Iran,” Archives of Agronomy and Soil Science, vol. 68, no. 5, pp. 597-614, November 2020. [Online]. Available: https://doi.org/10.1080/03650340.2020.1843637.

C. A. Alonzo, J. M. Galabay, M. N. Macatangay, M. B. Magpayo, R. Ramirez, “Drought Risk Assessment and Monitoring of Ilocos Norte Province in the Philippines Using Satellite Remote Sensing and Meteorological Data,” AgriEngineering, no. 5, pp. 720–739, April 2023. [Online]. Available: https://doi.org/10.3390/agriengineering5020045.

B. M. Catudan and N. I. Martin, “Coping Mechanisms of Farmers to Various Adverse Conditions in the Ilocos.” 2013 Biennial Convention, Philippine Agricultural Economics & Development Association. [Online]. Available: https://paedacon.wordpress.com/wp-content/uploads/2013/10/fullpaper_catudan_bethzaida.pdf.

M. Cotter, K. Berkhoff, T. Gibreel, A. Ghorbani, R. Golbon, E. A. Nuppenau, and J. Sauerborn, “Designing a sustainable land use scenario based on a combination of ecological assessments and economic optimization.” Ecological Indicators, vol. 36, pp. 779–787, January 2014. [Online]. Available: https://doi.org/10.1016/j.ecolind.2013.01.017.

H. I. Cobuloglu and I. E. Büyüktahtakin, “Food vs. biofuel: An optimization approach to the spatio-temporal analysis of land-use competition and environmental impacts,” Applied Energy, vol. 140, pp. 418–434, February 2015. [Online]. Available: http://dx.doi.org/10.1016/j.apenergy.2014.11.080.

W. Wu, Q. Yu, V. H. Peter, L. You, P. Yang and H. Tang, “How could agricultural land systems contribute to raise food production under global change?” Journal of Integrative Agriculture, vol. 13, no. 7, pp. 1432–1442, July 2014. [Online]. Available: https://doi.org/10.1016/S2095-3119(14)60819-4.

P. Peltonen-Sainio, L. Jauhiainen, E. Honkavaara, S. Wittke, M. Karjalainen and E. Puttonen. “Pre-crop values from satellite images for various previous and subsequent crop combinations,” Frontiers in Plant Science, vol. 10, pp. 1–13, April 2019. [Online]. Available: https://doi.org/10.3389/fpls.2019.00462.

S. Ma and Z. Wen, “Optimization of land use structure to balance economic benefits and ecosystem services under uncertainties: A case study in Wuhan, China,” Journal of Cleaner Production, vol. 311, August 2021. [Online]. Available: https://doi.org/10.1016/j.jclepro.2021.127537.

G. A. García, E. P. Rosas, A. García-Ferrer, and P. M. Barrios, “Multi-Objective Spatial Optimization: Sustainable Land Use Allocation at Sub-Regional Scale,” Sustainability, vol. 9, pp. 927, June 2017. [Online]. Available: doi:10.3390/su9060927.

C.M. Pascual, et al., Exploring Land Use Planning Options: Experiences and Challenges for Food and Water Security, Sustainability in Food and Water, An Asian Perspective, Springer Dordrecht, 2010, pp. 241-250. [Online]. Available: DOI 10.1007/978-90-481-9914-3.

T. Klein, A. Holzkamper, P. Calanca, R. Seppelt, and J. Fuhrer, “Adapting agricultural land management to climate change: a regional multi-objective optimization approach,” Landscape Ecology, vol. 28, pp. 2029–2047, September 2013. [Online]. Available: doi:10.1007/s10980-013-9939-0.

C. Wu, B. Chen, X. Huang, and Y. H. Dennis Wei, “Effect of land-use change and optimization on the ecosystem service values of Jiangsu province, China,” Ecological Indicators, vol. 117, no. 106507, October 2020. [Online]. Available: https://doi.org/10.1016/j.ecolind.2020.106507.

A. G. Laborte, “Multi-scale analysis of agricultural development: A modelling approach for Ilocos Norte, Philippines,” Agricultural Systems, vol. 94, no. 3, pp. 862-873, June 2007. [Online]. Available: https://doi.org/10.1016/j.agsy.2006.11.011.

F. M. Zenis, S. Supian, and E. Lesmana, “Optimization of Land Use of Agricultural Farms in Sumedang Regency By Using Linear Programming Models” IOP Conference Series: Materials Science and Engineering, vol. 332, no. 012021, October 2017. [Online]. Available: DOI:10.1088/1757-899x/332/1/012021.

M. T. Mellaku, T. W. Reynolds, and T. Woldeamanuel, “Linear Programming-Based Cropland Allocation to Enhance Performance of Smallholder Crop Production: A Pilot Study in Abaro Kebele, Ethiopia,” Resources, vol. 7, no. 76, November 2018. [Online]. Available: https://doi.org/10.3390/resources7040076.

A. Mohammadzadeh, J. Vafabakhsh, A.M. Damghani, and R. Deihimfard, “Optimal Land Allocation to Crop Production in Different Decision Priorities and Water Availability Scenarios: East Azerbaijan Province of Iran,” Archives of Agronomy and Soil Science, vol 68, no. 5, pp. 597-614, November 2020. [Online]. Available: https://doi.org/10.1080/03650340.2020.1843637.

G. P. L. Abella, F. P. Lansigan, and J. M. Tubay, “Agricultural Land Use Allocation Under Current and Projected Scenarios,” International Journal of Technology, vol. 12, no. 5, pp. 975-988, December 2021. [Online]. Available: https://doi.org/10.14716/ijtech.v12i5.5179.

Philippine Statistics Authority, “2019-2023 Crops Statistics of the Philippines,” www.psa.gov.ph, 2024. ISSN-2012-0487. [Accessed: April 1, 2025].

Q. Li, G. Hu, T.Z. Jubery, and B. Ganapathysubramanian, “A farm-level precision land management framework based on integer programming,” PLoS ONE, vol. 12, no. 3: e0174680, March 2017. [Online]. Available: https://doi.org/10.1371/journal.pone.0174680.

Y. Nie et al., “A Food-Energy-Water Nexus Approach for Land Use Optimization,” Science of the Total Environment, vol. 659, no. 1, pp. 7-19, April 2019. [Online]. Available: https://doi.org/10.1016/j.scitotenv.2018.12.242.

C. Buschbeck, L. Bitterich, C. Hauenstein, and S. Pauliuk, “Multi-objective Optimization Identifies Trade-offs Between Self-Sufficiency and Environmental Impacts of Regional Agriculture in Baden-Württemberg, Germany,” Journal of Agriculture, Food Systems, and Community Development, vol. 10, no. 1, pp. 43–62, October 2020. [Online]. Available: https://doi.org/10.5304/jafscd.2020.101.003.

R. Seppelt, S. Lautenbach, and M. Volk, “Identifying trade-offs between ecosystem services, land use, and biodiversity: A plea for combining scenario analysis and optimization on different spatial scales,” Current Opinion in Environmental Sustainability, vol. 5, no. 5, pp. 458–463, October 2013. [Online]. Available: https://doi.org/10.1016/j.cosust.2013.05.002.

A. Galan-Martin, C. Pozo, G. Guillen-Gosalbez, A.A. Vallejo, and L.J. Esteller, “Multi-stage linear programming model for optimizing cropping plan decisions under the new Common Agricultural Policy,” Land Use Policy, vol. 48, pp. 515-524, November 2015. [Online]. Available: https://doi.org/10.1016/j.landusepol.2015.06.022.

D. Makowski, E.M.T. Hendrix, M.K. Van Ittersum, and W.A.H. Rossing, “A framework to study nearly optimum solutions of linear programming models developed for agricultural land use exploration,” Ecological Modelling, vol. 131, no. 1, pp. 65–77, June 2000. [Online]. Available: https://doi.org/10.1016/S0304-3800(00)00249-0.

A. Kaim, A. F. Cord, and M. Volk, “A review of multi-criteria optimization techniques for agricultural land use allocation,” Environmental Modelling & Software, vol. 105, pp. 79-93, July 2018. [Online]. Available: https://doi.org/10.1016/j.envsoft.2018.03.031.

M.M. Najafabadi, S. Ziaee, A. Nikouei, and M.A. Borazjani, “Mathematical programming model (MMP) for optimization of regional cropping patterns decisions: A case study,” Agricultural Systems, vol. 173, pp. 218-232, 2019. [Online]. Available: https://doi.org/10.1016/j.agsy.2019.02.006.

Y. Liu, W. Tang, J. He, Y. Liu, A. Tinghua, and D. Liu, “A land-use spatial optimization model based on genetic optimization and game theory,” Computers, Environment and Urban Systems, vol. 49, pp. 1-14, January 2015. [Online]. Available: http://dx.doi.org/10.1016/j.compenvurbsys.2014.09.002.

Z. Jin and D. Ge, “Optimization of Sustainable Land Use Management in Water Source Area Using Water Quality Dynamic Monitoring Model,” Hindawi Computational Intelligence and Neuroscience, vol. 2021, no.1, pp. 1-10, December 2021. [Online]. Available: https://doi.org/10.1155/2021/3881092.

Y. Xu and L. Yao, “Integrating Climate Change Adaptation and Mitigation into Land Use Optimization: A Case Study in Huailai County, China,” Land, vol. 10, no. 12, November 2021. [Online]. Available: https://doi.org/10.3390/land10121297.

M. Xue, S. Ma, and S. M. ASCE, “Optimized land-use scheme based on ecosystem service value: Case study of Taiyuan, China,” Journal of Urban Planning and Development, vol. 144, no. 2, 1–11, March 2018. [Online]. Available: https://doi.org/10.1061/(ASCE)UP.1943-5444.0000447.

L. Zhang, S. Zhang, Y. Huang, M. Cao, Y. Huang, and H. Zhang, “Exploring an ecologically sustainable scheme for landscape restoration of abandoned mine land: Scenario-based simulation integrated linear programming and CLUE-S model,” International Journal of Environmental Research and Public Health, vol. 13, no. 4, pp. 1–10, March 2016. [Online]. Available: doi:10.3390/ijerph13040354.

M. T. Mellaku, T. W. Reynolds, and T. Woldeamanuel, “Linear Programming-Based Cropland Allocation to Enhance Performance of Smallholder Crop Production: A Pilot Study in Abaro Kebele, Ethiopia,” Resources, vol. 7, no. 4, November 2018. [Online]. Available: doi:10.3390/resources7040076. 2018.

B. Benli and S. Kodal, “A non-linear model for farm optimization with adequate and limited water supplies: Application to the South-east Anatolian Project (GAP) Region,” Agricultural Water Management, vol. 62, no. 3, pp. 187-203, October 2003. [Online]. Available: doi:10.1016/S0378-3774(03)00095-7.

P. T. Owombo, D. K. Adiyeloja, G. F. Koledoye, and M. A. Ijigbide, “Gross Margin Analysis of Amaranth Vegetable Production in Ondo State, Nigeria: A Gender Perspective,” Journal of Agriculture and Biodiversity Research, vol. 1, no. 6, pp. 91-96, 2012.

Bangko Sentral ng Pilipinas, “Financial Markets Reference Exchange Rate Bulletin,” www.bsp.gov.ph, 2025. [Online]. Available: https://www.bsp.gov.ph/SitePages/Statistics/ExchangeRate.aspx. [Accessed: August 1, 2025].

W. C. Enerlan and M. S. B. Bulayog, “Case Study on Profit-Maximizing Combination of Vegetable Crops for Small-Scale Farmers in Leyte, Philippines,” Review of Socio-Economic Research and Development Studies, vol. 4, no. 1, pp. 70-89, July 2021. [Online]. Available: https://ssrn.com/abstract=3876113.

A. Singh, “Better Water and Land Allocation for Long‐term Agricultural Sustainability,” Water Resources Management, vol. 36, pp. 3505–3522, June 2022. [Online]. Available: https://doi.org/10.1007/s11269-022-03208-y.

E. J. Mishan and E. Quah, Cost-Benefit Analysis, 6th ed., London: Routledge, 2020, pp. 1-404. [Online]. Available: https://doi.org/10.4324/9781351029780.

H. T. Ashebir, S. G. Kebede, and G. T. Mola, “Optimal Irrigation Scheduling of Garlic (Allium sativum L.) using Allowable Soil Moisture Depletion for Water Scarce Areas of Ethiopia,” Ethiopian Journal of Water Science and Technology, vol. 3, pp. 94-110, December 2020. [Online]. Available: DOI: 10.59122/1350A01.

S. C. Poonon, “Situationer and forecast of corn production in the Philippines: A time series approach,” Journal of Biodiversity and Environmental Sciences, vol. 23, no. 4, pp. 59-77, October 2023.

Philippine Statistics Authority, “Agriculture, Forestry, Fisheries: Crops,” https://openstat.psa.gov.ph, 2025. [Online]. Available: https://openstat.psa.gov.ph/PXWeb/pxweb/en/DB/DB__2E__CS/?tablelist=true&rxid=bdf9d8da-96f1-4100-ae09-18cb3eaeb313. [Accessed: April 1, 2025].

J. Magsasaka, “Watermelon (Pakwan) Cultivation Guide: All You Need to Know in Planting, Growing and Harvesting Watermelon,” www.juanmagsasaka.com, 2020. [Online]. Available: https://www.juanmagsasaka.com/2020/12/watermelon-pakwan-cultivation-guide- all.html?m=1. [Accessed: April 1, 2025].

Department of Agriculture-Agricultural Training Institute (ATI), Regional Training Center VII, “Watermelon Production Guide. Information Services Section,” https://ati2.da.gov.ph/ati-7/content/, 2020. [Online]. Available: https://ati2.da.gov.ph/ati-7/content/sites/default/files/users/user16/Watermelon%20Production%20Guide.pdf.

Japan International Cooperation Agency, “Survey on Issue Analysis of Food Value Chain in the Philippines (Final Report), www.jica.go.jp. 2019. [Online]. Available: https:// openjicareport.jica.go.jp/pdf/1000041342.pdf.

R. V. Gerpacio and A. P. Aquino, Socioeconomic Impacts of Bt Eggplant: Ex-ante Case Studies in the Philippines. International Service for the Acquisition of Agri-biotech Applications (ISAAA): New York and SEAMEO Southeast Asian Regional Center for Graduate Study and Research in Agriculture (SEARCA): Los Baños, 2014, pp. 1-338. [Online]. Available: https://www.isaaa.org/resources/publications/socioeconomics_impacts_of_bt_eggplant/download/Socioeconomics%20Impacts%20of%20Bt%20Eggplant.pdf.

E. D. Flores, R. SM. Dela Cruz, and M. C. R. Antolin, “Postharvest Handling Systems and Losses of Eggplant in Major Producing Areas of the Philippines,” Asian Journal of Postharvest and Mechanization, February 2018. [Online]. Available: doi: 10.13140/RG.2.2.13543.09128.

Philippine Statistics Authority, “Major Vegetables and Root Crops Quarterly Bulletin, April-June 2023,” www.psa.gov. ph, 2023. [Online]. Available: https://psa.gov.ph/vegetable-root-crops/eggplant. [Accessed: August 13, 2025].

H.D. Aumentado and M. A. Balendres, “Diseases of Eggplant (Solanum melongena L.) and Sustainable Management in Asia,” Plant Pathology & Quarantine, vol. 14, no. 1, pp. 98–117, September 2024. [Online]. Available: doi: 10.5943/ppq/14/1/9.

R. G. Maghirang, M. L. D. Guevarra, and G. S. Rodulfo, “Eggplant Production Guide,” https://cagayanvalley.da.gov.ph, 2009, Department of Trade and Industry-BMSMED: Makati City and DOST-PCAARRD: Los Baños. [Online]. Available: https://cagayanvalley.da.gov.ph/wp-content/uploads/2018/02/Eggplant.pdf. [Accessed: April 1, 2025].

R. M. Briones, “The Fertilizer Industry and Philippine Agriculture: Policies, Problems, and Priorities,” Philippine Journal of Development, Vol. 43, No. 1, November 2017, Philippine Institute for Development Studies. [Online]. Available: DOI: https://doi.org/10.62986/pjd2017.43.1b.

T. Sequeros, et al., “Mungbean in Southeast Asia and East Africa: varieties, practices and constraints,” Agriculture & Food Security, vol.10, no. 2, January 2021. [Online]. Available: https://doi.org/10.1186/s40066-020-00273-7.

Department of Agriculture-Regional Field Unit No. 02, “Tomato Production Guide,” https://cagayanvalley.da.gov.ph, 2008, Department of Agriculture-Agricultural Training Institute: Tuguegarao City. [Online]. Available: https://cagayanvalley.da.gov.ph/wp-content/uploads/2018/02/Tomato.pdf. [Accessed: April 1, 2025].

T. J. P. de Leon, and J. A. Manalo IV, “Affordances in crop diversification: Three cases from the Philippines,” Asian Journal of Agriculture and Rural Development, vol. 14, no. 2, pp. 34–50, May 2024. [Online]. Available: DOI: 10.55493/5005.v14i2.5089.

R. S. Langngag and R. L. Ladwingon, “Efficacy of organic fertilizers to Kalingas purple corn,” International Journal of Biosciences, Vol. 22, No. 4, pp. 148-155, April 2023. [Online]. Available: DOI: http://dx.doi.org/10.12692/ijb/22.4.148-155.

Department of Agriculture-Bureau of Agricultural Statistics, “Cost and Returns of Onion Production,” www.psa.gov.ph, Department of Agriculture: Quezon City, 2007.

Department of Agriculture-Regional Field Unit No. 02, “Pepper Production Guide,” https://cagayanvalley.da.gov.ph, 2017, Tuguegarao City, Cagayan. [Online]. Available: https://cagayanvalley.da.gov.ph/wp-content/uploads/2018/02/Pepper.pdf. [Accessed: April 1, 2025].

R. G. Maghirang, M. L. D. Guevarra, and G. S. Rodulfo, “Eggplant Production Guide,” https://cagayanvalley.da.gov.ph, 2009, Department of Trade and Industry-BMSMED: Makati City and DOST-PCAARRD: Los Baños. [Online]. Available:

https://cagayanvalley.da.gov.ph/wp-content/uploads/2018/02/Eggplant.pdf. [Accessed: April 1, 2025].

M. Danga, M. L. Mehriya, U. N. Shukla, G. R. Mali, and V. Laxmi, “Effect of weed management on growth and yield of mungbean [Vigna radiata (L.) Wilczek],” International Journal of Chemical Studies, vol. 8, no.4, pp. 3430–3432, June 2020. [Online]. Available: DOI: https://doi.org/10.22271/chemi.2020.v8.i4aq.10184.

T. Fujinaga, S. Yasukawa, and K. Ishii, “Tomato Growth State Map for the Automation of Monitoring and Harvesting,” Journal of Robotics and Mechatronics, Vol.32, No.6, December 2020. [Online]. Available: DOI: https://doi.org/10.20965/jrm.2020.p1279.

L. P. Wigati, Sutrisno, and E. Darmawati, “Losses and waste of tomato and red chili along the supply chain,” IOP Conference Series: Earth and Environmental Science, vol. 230, September 2018. [Online]. Available: doi:10.1088/1755-1315/230/1/012001.

D. Han, et al., “Advances in Mechanized Harvesting Technologies and Equipment for Chili Peppers” Agriculture, vol.15, no.11, May 2025. [Online]. Available: DOI: https://doi.org/10.3390/agriculture15111129.

DA-RFO No. 02, “Onion Production Guide,” https://cagayanvalley.da.gov.ph, 2012b. DA-RFO No.2: Tuguegarao City, Cagayan. [Online]. Available: https://cagayanvalley.da.gov.ph/wp-content/uploads/2018/02/onion_production_guide.pdf. [Accessed: April 1, 2025].

A. V. Domingo, “Economic appraisal and strategic analysis of the onion industry in the Philippines,” International Journal of Advanced and Applied Sciences, vol. 10, no. 8, pp. 78-90, June 2023. [Online]. Available: DOI: https://doi.org/10.21833/ijaas.2023.08.009.

R. D. Buenaseda, A. Daloonpate, and K. Vijitsrikamol, “Determinants of Using Cold Storage Technology: Insights from Onion Farmers in Bongabon and San Jose City, Nueva Ecija, Philippines,” ASEAN University Symposium for Sustainable Food System Faculty of Economics, April 2024. [Online]. Available: DOI: https://doi.org/10.22004/ag.econ.344460.

E. J. F. Guillermo and D. J. K. Edrada, “Clustered farming: How it supports small-scale farmers and boosts HVC production in Ilocos Norte,” www.pia.gov.ph, 2024. [Online]. Available: https://pia.gov.ph/clustered-farming-how-it-supports-small-scale-farmers-and-boost-hvc-production-in-ilocos-norte/. [Accessed: April 1, 2025].

Agricultural News Agency, “Purple corn exports totaled US$1,175,386 between January and August,” www.agraria.pe, 2023. [Online]. Available: https://agraria.pe/noticias/exportaciones-de-maiz-morado-suman-us-1-175-386-entre-enero--33257. [Accessed: July 2025].

The Freeman, “The power of purple: Why more farmers should grow this purple corn,” www.philstar.com, 2023. [Online]. Available: https://www.philstar.com/the-freeman/cebu-business/2023/07/06/2279090/power-purple-why-more-farmers-should-grow-purple-corn. [Accessed: July 2025].

N. Kasron, N. N. Ramli, R. Rusli, N. A. Saari, and N. F. M. Noh, “Public Willingness to Pay For Purple Corn Attributes,” Optimum: Jurnal Ekonomi dan Pembangunan, vol. 13, no. 1, pp. 60-69, March 2023. [Online]. Available: DOI: https://dx.doi.org/10.12928/optimum.v13i1.6668.

C. M. Balba, T. P. Baltazar, R. C. Dacones, D. D. Solis, Jr., and M. G. B. Gatan, “Peanut Production in Central Luzon, Philippines: An Assessment of Farmer Practices, Challenges, and Profitability,” Agricultural Science, vol.7, no.1, May 2025. [Online]. Available: DOI: https://doi.org/10.30560/as.v7n1p95.




DOI: https://doi.org/10.47738/jads.v7i3.1129

Refbacks

  • There are currently no refbacks.


Barcode

Journal of Applied Data Sciences

ISSN : 2723-6471 (Online)
Publisher : Bright Publisher
Website : http://bright-journal.org/JADS
Email : taqwa@amikompurwokerto.ac.id (principal contact)
    support@bright-journal.org (technical issues)

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0