Analysis of land suitability of clove (Syzygium aromaticum L.) in the humid tropics of South Sulawesi

South Sulawesi is one of largest clove-producing regions in Indonesia. The highest production was obtained in the Luwu, Regency area, but there needs to be data related to the wide distribution of clove development potential, especially in the Bua Ponrang District, the primary producer of clove commodities. Therefore, it is necessary to evaluate the suitability of clove plant land, which can show the area of its development potential in Bua Ponrang District, Luwu Regency. This study aims to analyze the suitability of land in the Bua Ponrang District for cloves, which can become a consideration for agricultural development in Luwu Regency. The method used in this study is a qualitative method with simple limiting factors with soil suitability assesment performed by comparing soil and physical environmental data with the suitability requirements of clove. The sampling method was purposive, conducted for each land unit most representative of the land unit map where clove exists, overlaid with geological maps, slope class maps and land use. The results of the analysis of the actual land suitability class, namely marginally suitable for clove (S3) to the boundary area of 6,222.18 hectares with limiting factors, namely air humidity, drainage, soil depth, total nitrogen (%), base saturation (%), available P (ppm) and slopes (%), which can be increased potential through improvement recommendations such as the addition of organic materials, fertilizers and terracing (conservation). The land suitability class is unsuitable for clove in the 2.570,12 hectares interface with limiting factors for erotion and slope hazard.


Introduction
Clove plant (Syzygium aromaticum L.) is a commodity with high selling value. The many uses of clove make it a needed commodity and increase its selling value [1]. Clove plants have environmental requirements to be able to grow and produce like loose soil. Good soil for clove growth is loose soil with a soil depth of 1.5 m, groundwater depth of more than 3 m from the soil surface and does not have a layer of impermeable soil. Andosol, latosol, regosol and red podzolic are soil types suitable for clove cultivation [5]. Land evaluation basically contains two main aspects of the land, namely physical resources and socio-economic resources. Physical resources are resources that are relatively stable including soil, topography and climate, while socio-economic resources vary depending on certain social and political conditions such as the area of land ownership, level of management, availability of labor, and other human activities [2]. Land evaluation is carried out to be able to achieve optimum land because the quality of land in each region varies and there are social changes and government policies [3]. According to the Directorate General of Plantations, the highest production of cloves in Indonesia is in Maluku Province. One of them is Amahai District, Central Maluku Regency which has a production  Based on data on clove plant production from the Agriculture Office of Luwu Regency, the productivity of clove plants in Bua Ponrang District has not been maximized. When compared with clove productivity in Amahai District, Central Maluku Regency, the productivity of Bua Ponrang District is still relatively low with productivity in the same year (2018) being 0.29 tons/ha with a planting area of 402 hectares. Bua Ponrang District and Luwu Regency are also producers of cloves which have great potential if they are further developed or optimized. However, in Bua Ponrang District, there is no information related to the analysis of land potential, especially for clove plants. In order for land management actions to remain sustainable and achieve optimum land use and land use according to its designation, analysis is needed to assess the potential of land resources by focusing on the limiting factors of cloves in land use.

Materials and methods
The tools and materials used in this study are shown in Table 1. The method used in this study is a qualitative method with simple limiting factors (simple method) [6] with land suitability assessment carried out by matching soil and physical environmental data with land suitability tables compiled based on land use requirements [6]. Data collection was carried out by means of a field survey. Field surveys were conducted to collect land biophysical data. Making a working map in question is making a map of land units, namely maps resulting from overlaid land cover maps, slope maps and geological maps. Land unit maps are used as a reference in determining sampling locations and observing soil profiles. Soil observation and sampling were carried out in each land unit. The sampling method was carried out by means of purposive sampling, namely sampling was carried out on behalf of each land unit by making a soil profile and was considered the most representative in each of these land units. The parameters of the research were soil color (Munsell soil color chart), soil texture (hydrometer), soil pH (pH meter), soil CEC and exchangeable bases (saturation of NH4Oac), P2O5 (Olsen and Bray), organic C ( Walkey and Black), N total (Kjeldhal) and K2O (25% HCl extract). Determination of land suitability for clove plants is adjusted to the suitability criteria for clove plants [6] shown in table 2.

Results and discussion
Bua Ponrang District is classified (Schmidt Ferguson climate classification) into climate type A (very wet) with an average number of wet months in the last ten years (2012-2021) is 12 months with total dry months for the last ten years being 7 months and humidity is 11 months [8]. The average air temperature in Bua Ponrang District (1991-2021) is 25.86°C [7] with an average air humidity in the last 11 years (2011-2021) of 86.39%. It has alluvium, lava and intrusion rock formations with a slope class range of 3-45% and land use is dominated by dry land and bush agriculture. In general, each land unit has surface rock <5 with good drainage except for land unit 1 which has obstructed drainage.

Potential land suitability
The land units that could not be repaired were land units 7, land units 10, land units 12, land units 14 and land units 16 which had a serious limiting factor for erosion and slope hazard and were included in category N (not suitable). Where this limiting factor indicates that the land unit is not suitable for clove cultivation and cannot be repaired because the slopes are observed to be steep. Land with high slopes cannot be used as agricultural land based on the safety level of use. There are many mechanisms that must be implemented in land management and require a large enough capital so that the management of the land requires special attention from the government. Land units that are very sloping are better conserved by reforesting so that the land degradation process can be stopped or at least can inhibit the  [9]. In addition, another way that can be done is to implement an agroforestry system. This agroforestry system is a way to restore land, limit erosion, regulate hydrological flows and restore soil fertility by combining forestry and sustainable agriculture [10] The limiting factor for water availability (wa) in this case is rainfall and humidity and the limiting factor for root media (rc) in this case the depth of the soil cannot be repaired because it is included in natural processes that occur naturally. From the results of the improvement efforts, potential land suitability is obtained, namely land unit 1 has the potential to change from S3oa,rc,nr,na to S3oa,rc, land units 2,3,11 and 13 have the potential to change from S3nr,na to S2wa (land unit 2) and S2wa,rc (land units 3, 11 and 13), land units 5 and 6 have the potential to increase to S2wa and land units 9 have the potential to change from S3na,eh to S2wa,rc.

Conclusion
The land suitability class of Bua Ponrang District is dominantly classified as marginally suitable (S3) for the development of clove plants and has the potential to increase its suitability by carrying out actions such as increasing soil fertility and proper slope management. The results of the actual land suitability evaluation for potential land shows that Bua Ponrang District, Luwu Regency has an actual land suitability class that has the potential to become a potential land area of 6,277.18 hectares.