Coffee is a woody perennial evergreen dicotyledonous plant that doesn’t shade its leaves for the entire year and it is a member of the Rubiaceae family (Thanuja & Singh, 2017; Weldon, 2016). Now a days, only two main species are used to cultivate coffee crop (Arabica coffee, or Coffea arabica) accounting to about 75–80% of the coffee that are produced globally. Coffea canephora, often known as Robusta coffee, makes up about 20% of all coffee and has a flavor which is distinct from Arabica coffee (Thanuja & Singh, 2017). Both these species share the same characteristics, namely a vertical main trunk and primary, secondary, and tertiary branches that are typically plagiotrophic in nature. If they are left unpruned, they can grow up to ten meters in height, however upkeep is always necessary for convenient harvesting (Abdisa, 2020; Weldon, 2016).
The main plantation crop grown in India’s southern states is coffee, with a tiny amount of coffee produced in the northern states of India. Where Kerala, Tamil Nadu, and Karnataka are India’s three largest coffee-growing states. This first spot belongs to Karnataka, which produces 71.03 percent of all coffee in India. The only three districts in Karnataka where coffee is grown are Kodagu, Chikmagalur, and Hassan. Approximately 45.66%, 38.99%, and 15.45% of the state’s total area and 54.06, 34.10, and 11.84 percent of its total coffee production are accounted for by these districts (Thanuja & Singh, 2017).
India is an agrarian country, and the production of coffee is important to the national economy. Since, India’s economy is totally dependent on agriculture. India is now the world’s sixth-largest producer of coffee in terms of productivity. India is the nation most impacted by climate change, especially in the southern regions where coffee is grown, according to the 2015 Global Climate Risk Index. Thus, weather, topographic and soil properties play a crucial role in the establishment and development of coffee plantations, leading to significant intra-seasonal production fluctuation. As a result, there are notable differences in coffee production performance amongst the nation’s various geographic areas. Therefore, according to India’s annual economic report, farmers make 20–25% less money as a result of poor weather and soil related problems (Chengappa and Devika, 2016).
The earth’s average temperature has been rising in recent years due to climate uncertainty brought on by pollution, solid waste management, population development, surface and global warming, and ground water hydrology. These changes have resulted in drastic alterations to the ecosystem. Today’s impoverished farmers have significant obstacles in growing coffee crops because of the frequent occurrence of droughts, heavy rains, floods, and landslides (Chengappa and Devika, 2016). Additionally, the unavailability of labor (small holders), high capital income to develop road infrastructure, transportation facilities, production facilities, and open residential land are the challenging issues faced by the farmers as most of the coffee location are situated in mountainous regions (Pagiu et al., 2020). In upcoming days, the land use for coffee farming may be less likely due to limited land availability and government regulations i.e., government are pushing farmers to convert from less productive annual crops to perennial grasslands, plantations, etc. in order to transition to organic farming (ThiTuyen et al., 2019). Thus, these factors may have a bigger influence on coffee cultivation, and this risk also affects the ongoing production of food (Mishra et al., 2016; Sharma et al., 2021).
Further it leads to other major issues that need to be resolved as soon as
possible, like food scarcity, deforestation brought on by urbanization, deteriorating agricultural land, etc. The most important step in achieving this is to complete the land suitability process. Therefore, by taking into account land assessments with comparable specific land abilities and comparing them with land use needs, the land suitability technique gives agronomists a better explanation of all such concerns. Land suitability is the process of determining the potential of land types by knowing the relationship between the circum- stances of uses and the land to which they are placed. A new model and analysis are essential with use of large number of datasets as input variables for this kind of operation.
Up to date, many researchers have applied methods to regulate the weights of factors for production of coffee crop to find out suitable land like Geographic Information System (GIS) approaches (Muliasari et al., 2022; Salas Lopez et al., 2020; Karim et al., 2020; Rono and Mundia, 2016; Nurfadila et al., 2020; Hidayat et al., 2020; Rahmatika et al., 2022; Hidayat et al., 2020; Abdisa, 2020; Ndabasanze, 2018; Bich and Phuong, 2023; Fachruddin et al., 2020; Nugraha, Prayitno, and Khoiriyah, 2021; Pravitasari et al., 2023; Chairani et al., 2017; Zhang et al., 2021; Eshete, 2022; Gross, 2014; Musli- hah et al., 2020; Ranjitkar et al., 2016; Nzeyimana et al., 2014; Neupane and Pangali Sharma, 2022; Pravitasari et al., 2023; Bindumathi, 2014; Nuary et al., 2022; Mighty, 2015; Rahmawaty et al., 2021; Barus et al., 2015; Hartono et al., 2018;Dermawan et al., 2018;Silaban et al., 2016; Weldon, 2016; Salima et al., 2012; Santoso and Ayu, 2022; Purba et al., 2019; Chairuddin et al., 2023; Tram et al., 2023; Pham et al., 2021; Gruter et al., 2022; Zhang et al., 2021; Ochoa et al., 2017; Gomes et al., 2020; D’haeze et al., 2005; Chemura et al., 2015; Raharja, 2016; Auliansyah, 2019; Liem & Duyen, 2020; Azsari et al., 2022), Fuzzy (Nurfadila et al, 2020; Neswati et al., 2023; Ranjitkar et al., 2016; Bindumathi, 2014; Zhang et al., 2021), AHP (Salas Lopez et al., 2020; Rono and Mundia, 2016; Abdisa, 2020; Zhang et al., 2021; Neupane and Pangali Sharma, 2022; Bindumathi, 2014; Mighty, 2015; Weldon, 2016; Pham et al., 2021; Zhang et al., 2021), parametric method (Marbun et al, 2019; Lop- ulisa et al., 2020; Juita et al., 2021; Nurdin et al., 2022; Pagiu et al., 2020; Juita et al., 2020), Non parametric methods like chi square test, ANOVA, Wilcoxon, Kolmogorov Smirnov tests (Ryder, 1994), MaxEnt (Zhang et al., 2021; Nuary et al., 2022; Purba et al., 2019; Gruter et al., 2022; Gomes et al., 2020; Chemura et al., 2015) and Weighted Overlay Analysis (Muliasari et al., 2022; Salas Lopez et al., 2020; Rono and Mundia, 2016; Rahmatika et al., 2022; Abdisa, 2020; Ndabasanze, 2018; Marbun et al., 2023; Chairani et al., 2017; Nzeyimana et al., 2014).
The literature revealed that traditional Multi-criteria Decision Analysis (MCDA) approaches to mapping land suitability for different agricultural crops are limited by a number of issues. These include: (i) AHP and fuzzy methods did not perform well in controlling land feature weights and computing LS values (Pramanik, M. K., 2016; Mistri & Sengupta, 2019; Reza et al., 2020; Zhang et al., 2015); (ii) AHP is limited to five to nine covariate or covariate groups and must closely monitor the upper limit of 0.10 CR, as advised by Saaty’s method, so that the inclusion of extra significant criteria results in further complex processing (Radocaj et al., 2021; Zhang et al., 2015); (iii) To evaluate the relative importance of the criteria discretely, the AHP method requires information from experts or multiple scientists and further if a variety of datasets are available, then using scientific data or objectives are required while deriving the pairwise comparison matrix (Zhang et al., 2015; Talukdar et al., 2022); (iv) Precaution should be taken when utilizing the AHP as any inaccurate parameter assessment may affect the weights and scores that are allocated (Hassan et al., 2020; Ramamurthy et al., 2020). Consequently, MCDA and AHP 9approaches are time consuming and cost-effective procedures in ground surveying and sampling without covering the spatio-temporal properties. Thus, Machine Learning (ML) models offer a potential remedy for the GIS-based MCDA in land suitability’s aforementioned shortcomings to map suitable zones in large spatio-temporal scales. Also, ML provides more complex computational efficiency and accuracy than traditional methodologies. Thus, through several research studies, it was suggested that ML algorithms outperform other modelling techniques for non-linear correlations to a variety of elements and environmental characteristics (Radocaj et al., 2021).
According to the previous researchers, a very few studies have been conducted or tested using machine learning like Bayesian network (Lara-Estrada et al., 2017; Lara-Estrada et al., 2021; Estrada, 2019), PCA (Irawan et al., 2022), MDA (Irawan et al., 2022), Correlation test (Irawan et al., 2022), Regression (Lopez-Carmona et al., 2023; Neswati et al., 2023; Marbun et al., 2023), Decision tree (Trangmar et al., 1995), ALES model (D’haeze et al., 29005; Trangmar et al., 1995) and Ecological niche modelling (Ranjitkar et al., 2016) in terms of land suitability and land capability for production of coffee crop. From the literature, it was noticed that an inadequate study on machine learning models to identify the suitable zones for coffee cultivation in the Malnad region of Kodagu district was carried out (Bindumathi, 2014). These limitations so prompted this work to suggest a new contribution to the literature. This study provides information on the coffee suitability zones and may improve regional land use laws.
The main objective of this work is to compare GIS based machine learning techniques to map the suitability of land in Somwarpet Taluk of Kodagu district for cultivation of coffee. To build decisional maps based on machine learning, a set of eight soil chemical properties (N, pH, Fe, S, K, EC and OC), one climatic factor (rainfall) and two topographic parameters (slope and elevation) were selected as the spatial input. Therefore, by taking into account of such parameters, this methodology can aid systematic assessment of coffee cultivation for the actual status of land suitability in Somwarpet Taluk of Kodagu district. Thus, this proposed approach is unique and a helpful tool for decision makers as it combines soil macronutrients data, topography and climatic data with use of soil micronutrients contents. The results of the study will help stakeholders and decision-makers to accomplish sustainable development objectives and keep raising regional coffee production output in Somwarpet Taluk of Kodagu district.