Assessing regional food security: A spatial analysis of food carrying capacity in Baki Subdistrict, Sukoharjo Regency – Indonesia

In Indonesia, addressing food security is challenged by a rapidly growing population, leading to increased consumption and diminished agricultural land availability due to ongoing land conversion. This study focuses on assessing the food carrying capacity in the Baki Sub-District as a critical component of regional food security. From a geographical perspective, the research employs spatial analysis to evaluate the food carrying capacity in the Baki Sub-District. Data collection involved the utilization of mathematical formulas, enabling a comprehensive analysis of the food carrying capacity. Spatial analysis was facilitated through a Geographic Information System (GIS). The findings reveal that a significant portion of the Baki Sub-District maintains a high food carrying capacity, particularly in the southern regions. However, areas proximate to Surakarta City, impacted by regional development, experience a reduction in food carrying capacity due to the conversion of agricultural land to residential use. This study contributes valuable insights into the spatial dynamics of food carrying capacity in the Baki Sub-District, providing essential information for regional food security planning.


Introduction
One of the issues that has been the concern of almost all countries in the world because of its influence on macroeconomic conditions is the issue of food security [1].In Indonesia, food security is also an important issue because it is related to the fulfillment of community welfare, which at a further level can affect economic and social stability [2], even political stability and security [1,3].The availability and affordability of food needs are still uneven in every region.The vast area and geographical conditions of the Indonesian archipelago are one of the causes of differences in the production of agricultural products in each region.
It is well known that the geographical conditions of the Indonesian archipelago are very diverse, including various soil types and fertility levels.The diversity of soil types and fertility levels affects the production of agricultural products [1].One of the materials that can increase soil fertility is volcanic material from volcanic eruptions.The number of volcanoes in an area will have a positive impact on the level of fertility in the area [4].Soils in Java Island with the influence of volcanoes that are still active and those that are inactive or dead have proven to be fertile areas for agricultural activities [3].1317 (2024) 012019 IOP Publishing doi:10.1088/1755-1315/1317/1/012019 2 Sukoharjo Regency is one of the regions in Central Java Province [5] which is geographically located between Merapi, Merbabu and Lawu Volcanoes.The presence of volcanic materials affects the fertility level of agricultural land in Sukoharjo District.Therefore, Sukoharjo District is one of the main producers of food crop agricultural products, especially for the Central Java region (Sadali, 2018) and generally for Indonesia.Sukoharjo District ranks 4th in the ranking of national food security index scores in 2018 [6].
Looking at these data, Sukoharjo Regency has an important role in maintaining the stability of national food security.This position needs to be maintained and even improved so that national food sovereignty can be realized.However, the challenge to maintain and even increase the productivity of agricultural products is not easy [7,8].The challenges faced include an increase in population and a decrease in agricultural land area [7,9,10].
Physical development is increasingly visible in Sukoharjo Regency.Like two sides of a coin, development always has positive and negative impacts.One of the negative impacts of regional development is the conversion of agricultural land [11].Population growth has implications for the increasing need for land for housing and supporting facilities [12,13].Agricultural land in locations close to growth areas often has to face the reality of being converted into residential areas and supporting facilities [14].
In terms of regional development, Sukoharjo Regency, especially Baki Sub-district, has been positively influenced by the development of Surakarta City.Its location, which is adjacent to and not so far from Surakarta City, makes Baki Sub-district get an abundance of blessings from the development of Surakarta City.The impact of this condition is that quite a lot of paddy fields have been converted into non-field land.Paddy fields in Baki Sub-district that have been converted into non-field functions in the last 7 years (2013-2020) reached 176.69 ha (Figure 1).This is not a small amount for a sub-district that serves as one of the rice producers in Sukoharjo Regency.The number of paddy fields that have been converted to non-field functions can reduce productive land for food agriculture [11].The implication of reduced agricultural land is a decrease in the production of agricultural products [14].If this condition continues, it is not impossible that it can threaten the food security of an area [15].For this reason, a food carrying capacity study is needed as an evaluation effort for sustainable food security.
In general, this research aims to evaluate the condition of agricultural land related to food carrying capacity in Baki Sub-district, one of the food producers in Sukoharjo Regency (Figure 2).Specifically, the objectives to be achieved from this research are: (1) to analyze food carrying capacity in Baki Subdistrict; (2) to spatially analyze food carrying capacity in Baki Sub-district.

Data collection techniques
Data on population, rice field area, and crop yields were obtained from the Sukoharjo Regency Central Bureau of Statistics.Spatial data including data on the administrative area, road network, river network, and land use of Baki Sub-district were obtained from the Indonesian Earth Map published by the Geospatial Information Agency.

Data analysis method
To calculate the food carrying capacity of Baki Sub-district, a mathematical approach (1) was used, which considers food availability and demand in each village.The formula used is [16]: Description: DDP = Food Carrying Capacity Lp = Harvest area (ha) Pd = Total population (people) KPB = Rice demand per capita, 154.1 kg/capita/year (Food Security Agency) Pr = Average land production per hectare (kg/ha) 0,632 = Constant for conversion from paddy to rice Based on the DDP formula, the food carrying capacity value can be interpreted as follows: DDP > 1 = high food carrying capacity DDP = 1 = optimum food carrying capacity DDP < 1 = low food carrying capacity Spatial analysis of food carrying capacity is conducted using Geographic Information Systems (GIS).Spatial analysis with GIS for food carrying capacity has been commonly used [14,17,18].

Overview of the Research Area
Baki Sub-district is one of the sub-districts in Sukoharjo Regency, Central Java Province.Baki subdistrict occupies an area of 2,197 hectares or about 4.71% of the area of Sukoharjo Regency [19].The distance from the capital of Sukoharjo Regency is approximately 15 km.The area to the north is bordered by Kartasura Sub-district and Surakarta City, the south is bordered by the Regency, the east is bordered by Grogol Sub-district, and the west is bordered by Gatak Sub-district.
According to data from BPS Sukoharjo, 2020, Baki Sub-district is administratively divided into 14 villages consisting of 35 hamlets/services, 110 RW, and 369 RT [5].According to the classification of villages in the sub-district, 2 villages are considered Swasembada villages and 12 villages are considered Swakarya villages.The names of the villages and their areas are presented in Table 1.  1 shows that the village with the largest area is Mancasan Village, which is 276 hectares (12.56%), while the village with the smallest area is Kadilangu Village, which is 111 hectares (5.05).

Land Use
Most of the land in Baki Sub-district has been utilized by the community for various types of uses.In relation to the food carrying capacity of the region, the land use in Baki Sub-district can be classified into paddy fields, yards and others (Figure 3).Paddy fields occupy 1,199 hectares, yards occupy 854 hectares, and other land uses occupy 144 hectares.The land use of each village is presented in Table 2.
Table 2 The area with the most extensive rice fields is Mancasan Village with an area of 158 ha.The second largest area is in Kudu Village, which is 146 hectares.The smallest area of paddy fields is in Gentan village, which is 17 hectares.The largest land use for yard is in Gentan Village, which covers 118 hectares, while the smallest is in Bentakan and Duwet Villages, which cover an area of 29 hectares.

Rainfall Rate
Monthly rainfall can describe weather conditions in an area.In relation to food carrying capacity, rainfall is related to the availability of water for rice farming activities in rice fields.Monthly rainfall is the average rainfall in one month recorded at one observation station.Monthly rainfall data and average monthly rainfall in Baki Sub-district can be seen in Figure 2.
The highest rainfall occurred in January at 490 mm while the lowest rainfall occurred in July and August at 0 mm.A more complete diagram of monthly rainfall (in millimeters) in Baki Sub-district is presented in Figure 4.

Population size and distribution
The total population of Baki Sub-district in 2019 is 85,277.42,248 of the population are male and 43,029 are female.The village with the highest population is Gentan Village, which is 9,511 people.
The village with the smallest population in Baki Sub-district is Kadilangu Village, with a population of 4,227.The complete population data for each village is presented in Table 3.

Population density
Population density is the number of people per square kilometer.In Baki Sub-district, the average population density is 3,882 people per square kilometer.The highest population density is in Gentan Village at 6,892 people per square kilometer.The lowest population density is in Kudu Village at 2,121 people per square kilometer.The complete population density data for each village in Baki Subdistrict is presented in Table 3.

Food Carrying Capacity
To calculate the food carrying capacity of Baki Sub-district, a mathematical approach is used that considers food availability and needs in each village.

Harvest area
Harvest area is the accumulated harvest area in one year.In one year, rice can generally be harvested 3 times for those who get good irrigation.However, there are also farmers who harvest rice twice a year because it is interspersed with planting secondary crops once a year.Generally, those who planted rice twice and then planted secondary crops were areas that were far from irrigation channels so that in the dry season they did not or had difficulty getting water from irrigation.Farmers choose to plant secondary crops because they require less water than rice.The area, rice field area, and harvest area of each village are presented in Table 4.  4, it can be seen that the largest harvest is in Kudu Village with a harvest area of 320 ha.This result was obtained from three times harvesting on 146 ha of paddy fields.The least harvest is in Gentan Village with a harvest area of 51 ha.The result was obtained from 3 harvests on 17 ha of paddy fields.The rice field in Gentan Village is the smallest compared to other villages in Baki Sub-district.

Rice production
Rice production is the amount of rice produced from productive paddy fields in one year.Similar to the harvest area discussed earlier, rice paddy production is also an accumulation of harvests for one year.In one year, there are rice fields that are able to achieve three harvests, but there are also those that only harvest twice.Rice production of each village in Baki Sub-district is presented in Table 5.
Based on Table 5, it can be seen that the highest rice production was achieved by Mancasan Village with a total of 2,938 tons.Meanwhile, the smallest rice production was in Waru Village with a total of 141 tons.In order to calculate the region's food security, data on average rice production in kg/ha is required.For this reason, rice production in tons was converted into kilograms before the average production was calculated.From the results of the calculation, the highest average for rice production per hectare of rice field was in Siwal Village, producing 7,621 kg/ha.Meanwhile, the lowest average for rice production per hectare of rice field was in Waru Village with an average of 792 kg/ha.

Value of harvested area by population
The value of harvested area by population is obtained from the total harvested area per hectare for one year divided by the total population.The harvested area by population in each village is presented in Table 6.6 shows that the highest value of harvested area by population is in Kudu Made Village, which is 0.07.Meanwhile, the lowest value of harvested area by population is 0.01 in two villages, Gentan and Purbayan village.

Rice consumption per capita
The rice consumption per capita refers to the standard set by the Food Security Agency, which is 154.1 kg/capita/year.

Average rice production
The average rice production is obtained from multiplying the average rice production (grain) by the grain-to-rice conversion constant which is 0.632.The results of the analysis of the average value of rice production per village are presented in Table 7.

Spatial distribution of food carrying capacity in Baki Sub-district
The spatial distribution of food carrying capacity in Baki Sub-district was analyzed using geographic information system (GIS).Analysis of food carrying capacity with geographic information systems has also been carried out by Ndoen et al. [17].The results of the spatial analysis of the food carrying capacity of Baki sub-district are presented in Figure 6.By depicting spatially, it can be seen that areas with high food carrying capacity are mostly located in the southern part of Baki sub-district, while areas with low food carrying capacity are generally located in the northern part of Baki sub-district.When associated with regional development, areas with low food carrying capacity are generally developing areas, especially those adjacent to Surakarta City.The increasingly limited land for settlements in Surakarta City has made many people who work or do activities in Surakarta City choose to live or build houses in hinterland areas such as Baki Sub-district.This has an impact on the reduction of agricultural land due to its conversion to residential use.

Conclusion
Based on the research conducted as described in the previous discussion, it can be concluded that the food carrying capacity in Baki Sub-district is generally classified as high.There are eight villages with high food carrying capacity, namely Ngrombo, Mancasan, Gedongan, Bentakan, Kudu, Menuran, Duwet and Siwal.Meanwhile, villages with low food carrying capacity are Jetis, Kadilangu, Bakipandeyan, Waru, Gentan, and Purbayan.Spatially, the distribution of low food carrying capacity areas is spread in most of the northern area of Baki sub-district, while high food carrying capacity areas are found in the southern area of Baki sub-district.Village areas close to Surakarta City are influenced by the development of the area, but it has an impact on the conversion of agricultural land into residential land, thus reducing the food carrying capacity.

Figure 1 .
Figure 1.Conversion of Agricultural Land to Settlement in Baki Sub-district

Figure 4 .
Figure 4. Monthly rainfall diagram in Baki sub-district

Figure 5 .
Figure 5. Food carrying capacity of Baki sub-district

Table 1 .
Villages and Area in Baki Sub-district

.
Land use of each village in Baki Sub-district

Table 3 .
Population density of each village in Baki Sub-district

Table 4 .
Total area, rice field area, and harvested area of each village in Baki Sub-district

Table 5 .
Rice production of each village in 2019

Table 6 .
Harvested area by population

Table 7 .
Average rice production per hectare of each village Food carrying capacity of each village Food carrying capacity in this study was analyzed using the analysis unit of village.The results of the analysis are shown in Table8.The table shows that most villages in Baki sub-district have high food carrying capacity.Some villages have low food carrying capacity.

Table 8 .
Food carrying capacity of each village in Baki Sub-district