Cropland Conversion and Its Effect on Rice Production in Lampung Province, Indonesia

Lampung Province is one of the national rice producers in Indonesia. This study aimed to determine the patterns of cropland conversion, specifically rice fields, and available rice fields from 2013-2018 and to analyze the effects of two independent variables (rice field area and rice field conversion rate) on the dependent variable, i.e., total rice production. The conversion rate was calculated from 2013 to 2018, then categorized into three classes, and spatially mapped with rice field area and availability. Multiple regression tests were conducted to determine the relationship between the two independent variables. Results show that while rice fields were concentrated in Lampung Selatan, Lampung Tengah, and Lampung Timur, their conversion to non-agricultural lands was found throughout the province. Rice field areas increased in the north and east but shrunk in the south, west, and center. The statistical analysis revealed that rice field area, conservation rate, and their combination do not affect the amount of rice production in most regencies/cities in the province.


Introduction
The agricultural sector plays a crucial role in Indonesia as it is the primary source of food production and provides livelihoods.Food resources encompass a wide range of products, both in processed and unprocessed forms, that are obtained from aquatic environments and natural resources.Rice, in particular, is the staple food for most Indonesians and is central to their dietary needs.
Lampung Province has seen a population growth of 1.65% between 2010 and 2020.This demographic change has led to a rising demand for rice each year.Unfortunately, rice fields are gradually decreasing in size as a result of land-use change into non-agricultural areas [1], posing a threat to food security in the province.Lampung is historically one of the leading rice-producing regions.According to the Bureau of Statistics (BPS), rice production decreased by 6.22%, aligned with a conversion rate of 10.19% observed in the province's rice fields from 2020 to 2021.This decline was higher than the national average of -2.3%.The primary reason for the decline is the reduction in rice field areas, a critical influencing factor of rice production.Rice fields have been repurposed for nonagricultural uses, such as toll roads, residential areas, industrial zones, cassava and rubber plantations, and orange tree orchards [2].Rice fields are more susceptible to conversion for non-agricultural than agricultural purposes [3,4], and this trend has also been observed in other regions like Sleman (Yogyakarta) and the newly established North Kalimantan due to infrastructure development in the Bulukan and Nunukan areas.
Topography, soil quality, water availability, and the presence of flora and fauna significantly affect the productivity of rice fields [5].According to the Office of Agriculture in the province, not every land in Lampung is arable and can be cultivated for rice production due to various constraints, such as water IOP Publishing doi:10.1088/1755-1315/1313/1/012030 2 scarcity and plant disease outbreaks [6].These challenges emphasize the importance of carefully managing land-use conversion to preserve rice fields in potential areas.If left unmanaged, this land-use change can threaten rice production and availability, even with existing intensification measures.Based on findings in Lapatandau et al. [7], demographic and economic growth are among the driving factors of rice field conversion.Moreover, they provided a perspective that extends beyond tracking the distribution of converted rice fields to understand the spatial dynamics of rice field availability and food resources.
Given the aforementioned issues, this study sought to identify the patterns of rice field conversion, rice field availability, and rice production and to analyze the impact of rice field area and conversion rate on total rice production.

Data collection
This research employed descriptive quantitative methods, used secondary data obtained from the government (Table 1), and presented them in tables and maps.

Topographic and land-use maps (RBI) of Lampung Province
To assist in analyzing and understanding the physical conditions of the province Geospatial Information Agency

Spatial and temporal distribution analysis
The conversion rate of rice fields (V, in %) was calculated using a partial method that compared the rice field areas in the previous year (Lt-1, ha) and the current year (Lt, ha), as proposed by Rizkiani and Sudrajat [8] and Santoso [9]: Furthermore, the analysis results were visualized into maps and graphs to show the spatial and temporal perspectives.The resulting conversion rates (X) were grouped into three classes (high, medium, or low) according to the median value (M) and the standard deviation (SD): -Low rate: X < M -1 SD -Medium rate: M -1SD ≤ X -High rate : M + 1 SD > X (Source: Azwar, 2012)

Correlation between variables
Multivariate analysis was conducted in the SPSS program to discover the correlation between two independent variables (rice field conversion rate and rice field area) and the dependent variable, rice production.The analysis consisted of t-test and F-test, which aimed to prove the following hypotheses: H1: Rice field area (X1) determines rice production (Y) H2: Rice field conversion rate (X2) determines rice production (Y) H3: Rice field area (X1) and conversion rate (X2) simultaneously determine rice production (Y).H1 and H2 were proved using a t-test, while H3 was analyzed with an F-test.Afterward, a double regression test was conducted to predict the value of the dependent variable from the values of the two independent variables.This test produced a model summary table containing an R 2 value that explained the simultaneous effect of X1 and X2 on Y.The R 2 value was calculated using the equation below [9]: where ri is a coefficient of correlation (i: 1, 2, 3) for each pair of independent-dependent variables, xi is the conversion rate (x1) and the rice field area (x2), R is the coefficient of multiple correlation, and y is total rice production.

Determination of rice demand and availability
The rice demand in each regency in the province was calculated according to KFM or daily calory requirement, which was 2,600 or equivalent to 265 kg of rice per person per year [10,11].The amount of rice that the population needed was computed using the equations below: Afterward, rice availability was estimated based on data from the Food Security Agency using the equations below: where P is rice production (calculated from dry milled grains (DMG), tonne/year), s is a reduction factor in the form of seeds (0.9%), f is animal feed (0.44%), w is rice residues (5.4%), c is the conversion factor from dried milled grains to rice grains (63.82%),Pnet is netto rice production in dried milled grains (kg), Rnet is netto rice production in rice grains (kg).With four planting seasons per year, the annual rice availability was estimated using the equation below:

Physical and socioeconomic conditions of the study area
Lampung Province encompasses a total area of 33,553.35ha, which comprises the mainland, 188 small islands, and the sea.The province is divided into thirteen regencies and two cities.The physical landscape is composed of diverse topographies and vegetation covers (Figure 1).Physically, it has five topographic units: hilly to mountainous areas, rolling to undulating areas, alluvial plains, tidal swamps, and river basins.The hilly area is predominantly covered by primary or secondary forest vegetation, and the rolling to undulating terrain is characterized by various plantations (e.g., cloves, coffee, and pepper) and croplands (maize, rice, and vegetables).The alluvial plains are located in the east and west; the eastern one is situated in Lampung Tengah and spans until the eastern coast, which is the lower reach of rivers originating in Lampung Timur.Lampung is located below the equatorial line at 5S and has a humid tropical climate, significantly affecting its air temperature and humidity.Climate records in 2021 showed temperatures in the range of 19.6-34.8C,with a high monthly average of around 27.1C, with an average humidity of 81.7% and a minimum of 37% during the dry season.
The most recent data in 2021 showed that the province had a total population of 9,081,792, with the majority residing in Central Lampung Regency and Bandar Lampung City.Since 2020, Lampung has been the second most populous province in Sumatra.However, the population is not evenly distributed across the regencies/cities due to geographical constraints and transportation/public facilities.Economically, most agricultural activities in Lampung began in the Dutch Colonial period through the 1313 (2024) 012030 IOP Publishing doi:10.1088/1755-1315/1313/1/0120304 transmigration program.During that time, people were relocated to, among others, Gading Rejo-Pringsewu, Wonosobo, and Trimurjo-Metro to clear forests and create primary or uncontaminated lands for agriculture to develop the irrigation system and increase the economy of the transmigrants.Transmigration proves influential on agricultural development in the province.However, in 2019, the number of farm workers decreased, while the number of industrial workers tripled due to industrialization.

Figure 1. Map of the topographic conditions of the Lampung Province
Source: Geospatial Information Agency (Data Analysis, 2023)

Spatial and temporal patterns of the rice field conversion
The conversion of rice fields into non-agricultural lands occurs in not only urban areas but also rural regions.The rice fields in Lampung decreased from 365,176 ha in 2013 to 364,158 ha in 2018, indicating a loss of 1,108 ha in six years between the beginning and the end of the observation period.The conversion of croplands, including rice fields, has been a widespread problem in Indonesia, and it can only be reversed by opening new rice fields.It reduces the total harvested area and, simultaneously, deteriorates the productivity of the surrounding regions, thus substantially diminishing food availability.Therefore, it is necessary to evaluate and formulate strategies to improve the welfare of farmers to prevent the conversion of rice fields for presumably more profitable non-agricultural purposes, which threatens national rice production.
Figure 2 shows that the conversion rate of rice fields into non-rice fields in Lampung increased from 2013 to 2015 but decreased to below zero from 2015 to 2018.The conversion rate in the first half of the period increased due to the implementation of a new regulation (LP2B) that protects rice fields in the province in 2014.From its introduction in 2014 until 2017, the decline in the conversion rate was successfully stopped, and more areas were transformed into croplands.Agricultural extensification refers to the expansion of agricultural land by clearing and cultivating unproductive land with crops.The reduction of rice fields was centered in the south and west due to the increasing demand for industrial complexes, residential areas, factories, and offices [10].The construction of toll roads also created a multiplier effect in the form of areal zoning to build new industrial centers, e.g., in Lampung Selatan, Tanggamus, Mesuji, Lampung Tengah, Way Kanan, Tulang Bawang, Tulang Bawang Barat, Pesawaran, and Bandar Lampung City.These areas experienced a significant reduction in rice fields in 2018.Part of the Bukit Barisan Mountains in the west is suitable for vegetable farming and plantations.Meanwhile, Lampung Tengah, which had the most extensive rice fields in 2013-2018, maintains its rice production by extensification.Table 2 shows the average rice field conversion rate in the south, north, central, east, and west during the 2013-2018 period.In the north, rice fields were changed into non-agricultural land at a rate of 2.44%, indicating that the government and the community worked together to expand the agropolitan area per Regional Regulation No. 1 of 2010 on the Spatial Plan of Lampung Province for 2009-2029.In the east and center the conversion rates moderately 1.39% and -0.32 because that area is a rice barn.Meanwhile

Spatial distribution of rice fields and rice production
In Lampung, rice farming is practiced extensively, primarily due to the continued land expansion to improve lowland rice production.Like other regions outside Java Island as the center of national demographic and economic growth, Lampung has a lower population density that facilitates the expansion of rice cultivation.The spatial distribution of rice field areas during the observed years remained largely consistent (Figure 4).This consistency can be attributed to the uneven distribution of administrative boundaries and the presence of areas that have, from the outset, extensively utilized their land for rice cultivation due to favorable geographical conditions.Examples of such areas include Lampung Tengah, Lampung Timur, Lampung Selatan, and Tulang Bawang.Figure 5a presents maps illustrating the distribution of rice field areas in Lampung in 2013 into three classes: low (< 7,908 ha), medium (between 7,908 and 39.057 ha), and high (> 39.057 ha). Figure 5b presents maps illustrating the distribution of rice field areas in Lampung in 2013 into three classes: low (< 8.106 ha), medium (between 8.106 and 39.208 ha), and high (> 39.028 ha).Bandar Lampung and Metro Cities were classified as two administrative regions with low rice field areas, which can be attributed to their notably small areas, 18,331 ha and 7,315 ha, respectively.Further, Bandar Lampung primarily serves as an administrative, residential, and commercial hub and is not designated as a rice production center.Located in the south, Bandar Lampung has a multiplier effect on its surroundings, i.e., economic fluctuations, often in regions with a strong interconnection with the focal area [11].In the south, the Lampung Selatan Regency maintains close ties with Bandar Lampung City, as evident from the establishment of the Sumatra Institute of Technology in Jatiagung District on Jl.Terusan Ryacudu, a road that directly links this regency to Bandar Lampung.Additionally, Lampung Selatan has Bakauheni Harbor and Radin Inten II International Airport, which facilitates transportation between local areas and islands.This, in turn, generates a high multiplier effect characterized by significant population growth.The conversion rate of rice fields into built-up land was considerably high (-20%) during the 2017-2018 period.Lampung Selatan had a larger rice field area than Pesawaran⎯another district in the southern region, but in these years, the conversion rate was substantially higher in the latter (14.44% expansion) than in the former (2% expansion).
The central region includes Lampung Tengah Regency, Metro City, and Pringsewu Regency, which share a common feature: a substantial proportion of rice fields in their respective areas.Topographically, these regions are alluvial plains formed due to sedimentation by rivers that flow into Lampung Timur.Therefore, they are characterized by lowland terrain and gentle slopes, and the elevation gradually decreases eastward.Rice fields with an irrigation system were established upon the arrival of immigrants from Banten, who cultivated rice from the coast of Lampung Selatan to Lampung Timur.Currently, districts like Trimerjo (Lampung Tengah), Metro, and Gadingrejo (Pringsewu) have the highest rice field density in the province.The above irrigation system has been duplicated and developed into multiple irrigation systems in Way Sekampung.Lampung Timur and Tulang Bawang are located east of the southern region.Geographically, they share some similarities with the central region, presenting itself as an alluvial plain.Lampung Timur physically consists of undulating areas, extensive alluvial plains, and tidal regions.Previous research indicates that alluvial deposits contain various mineral compositions [16], depending on the source of weathering.Typically, alluvial rice fields are rich in feldspar, thus ensuring long-term soil fertility.Another characteristic of alluvial plains is the presence of numerous rivers, suggesting abundant water supplies.The rice fields in the eastern region account for 27.9% of the total rice field area in the province and 52.8% of them are irrigated.Notably, Tulang Bawang witnessed the largest number of new rice fields during the 2013-2018 period, up to 6,022 ha or a positive conversion rate of 35.47%.This substantial increase can be attributed to programs promoting the establishment of new rice fields and initiatives to enhance planting indices (IP) in specific areas through the additional planting area (LTT) program [2].The Tulang Bawang government has also initiated intensification, extensification, and diversification activities to boost food self-sufficiency.This commitment has been recognized with national awards in the agricultural sector between 2007 and 2012.
Geographical, social, and local government policies influence the distribution of rice fields in Lampung.The southern region accounts for 13.8% of the province's rice field area (irrigated and rainfed).However, due to urbanization, the southern rice fields gradually diminish.On the contrary, sustainable rice fields can be found in the eastern, central, and northern regions, where the government is actively promoting agricultural expansion despite challenges like drought in Lampung Utara and Tulang Bawang Barat and flooding in Mesuji.
The governments of Lampung Tengah, Pringsewu, Lampung Timur, Tulang Bawang, and Pesawaran are committed to maintaining their roles as key rice producers in the province.An example of this commitment is designating more croplands through the LP2B (Land for Food Crops) program, and according to Regional Regulation No. 17 of 2013, these districts have exceeded their respective LP2B targets.On the contrary, in 2018, Lampung Barat, Tanggamus, and Lampung Utara had yet to achieve the said targets, and Pantai Barat had yet to implement the LP2B program at all.
Figure 6a presents maps of rice production in Lampung in 2013 into three classes: low (<62.069tonnes of dry milled grain or DMG), medium (between 62.069 and 388.467 tonnes of DMG), and high (> 388.467 tonnes of DMG).In 2013, Lampung produced 3,042,419 tonnes of dry milled grains (DMG), with an average rice production of 202,827 tonnes of DMG for all regencies/cities.Lampung Utara was the largest rice-producing area, contributing 673,564 tonnes of DMG, or 22.14% of the total rice production in 2013.Conversely, Pesisir Barat had the lowest rice production, with 72,506 tonnes of DMG, accounting for only 2.38% of the provincial production.Cities like Bandar Lampung and Metro, with limited rice field areas, naturally had the lowest rice production, as they primarily serve as residential, administrative, industrial, trade, and cultural centers.
Figure 6b presents maps of rice production in Lampung in 2018 into three classes: low (<90.890tonnes of dry milled grain or DMG), medium (between 90.890 and185.419tonnes of DMG), and high (> 185.419 tonnes of DMG).By 2018, the total rice production in Lampung had reached 4,106,646 tonnes of DMG, marking a 35% increase compared to 2013.Although there was a sharp increase in production in 2017, it was immediately followed by a decrease in 2018.The average rice production reached 388,467 tonnes of DMG.Lampung Tengah maintained its status as the top rice producer, contributing 724,923 tonnes of DMG, or equivalent to 17.65% of the total rice production.Significant increases in rice production were observed in Mesuji and Tulang Bawang Barat, which could be attributed to the large-scale establishment of new rice fields in 2017.However, several regions experienced a decline in rice production, including Tanggamus, Lampung Selatan, Lampung Timur, Lampung Tengah, Pesawaran, and Tulang Bawang Barat.The rice productions of Lampung Timur, Tanggamus, Tulang Bawang, and Mesuji showed increased contributions during the 2013-2018 period, while those of Lampung Selatan, Lampung Tengah, and Lampung Timur reported some declines.
Because the total rice field area was shrinking, increased rice production could be attributed to rice productivity improvement.Rice productivity is defined as the weight of dry milled grains produced per hectare.In the 2013-2018 period, rice productivity consistently increased and reached 11.28 tonnes of IOP Publishing doi:10.1088/1755-1315/1313/1/0120309 DMG per hectare.Tanggamus had the highest productivity, 18.11 tonnes of DMG per hectare, whereas Lampung Tengah had a much lower productivity, 9.33 tonnes of DMG per hectare, even though it is the province's rice granary.Conversely, Metro City reported the lowest productivity at 11.28 tonnes of DMG per hectare, while Bandar Lampung City had a high rice productivity of 14.45 tonnes of DMG per hectare, potentially due to better access to agricultural facilities and improvements.Factors influencing productivity include subsidized fertilizers (type and amount), water availability during the dry season, the use of superior or resistant varieties, and resistance or susceptibility to pests.Kanan), southern (Pesawaran), and western regions (Tanggamus).Mesuji experienced a remarkable 195% acceleration in rice production in 2018, improving its production from low to medium.Meanwhile, regions closer to the Bukit Barisan Mountains reported decreased rice production due to unsuitable land resources for rice cultivation.In 2013, regions with low rice production were situated in the west (Lampung Barat and Pantai Barat), south (Bandar Lampung City), center (Pringsewu and Metro City), and north (Tulang Bawang Barat and Mesuji).In 2018, Pesawaran's rice production was categorized as low because of substantial fluctuations in rice yields, with rice production increasing by only 23% from 2013 to 2018.The rice production in the western region remained unchanged because its main administrative and economic functions did not involve rice farming.

Correlation analysis between rice field area, conversion rate, and total rice production
Table 3 summarizes the statistical effects of rice field area and conversion rate on total rice production in Lampung from 2013 to 2018, assessed at the regency/city level.Table 4 shows how much the combined effect of rice field area and conversion rate can explain variations in total rice production.The regencies/cities were categorized into three groups based on the correlation analysis.The first group comprises twelve areas: Lampung Barat, Tanggamus, Lampung Selatan, Lampung Tengah, Lampung Utara, Tulang Bawang, Pringsewu, Mesuji, Tulang Bawang Barat, Pesisir Barat, and Bandar Lampung.These areas showed Sig.values > 0.05, t-count < t-table, and f-count < f-table, meaning that H1, H2, and H3 were rejected.This outcome implies that rice field area, land-use conversion rate, and their interaction have no significant effect on rice production.The first two factors alone could explain 11.9 to 63.3% variations in rice production (Table 4).Other factors, such as technology, human resources, soil fertility, and capital, play a more significant role in influencing rice production.Specifically, changes in rice field area and conversion rate do not affect 13% of regencies/cities with high rice production and 53% with medium rice production.The second group consists solely of Metro City, where H1 and H3 were accepted, but H2 was rejected.This suggests that rice production is influenced by rice field area and the combined effect of rice field area and conversion rate, but not by conversion rate alone.The combined effect was the most significant, accounting for 88.1% of the total effect.Metro City allocates its land predominantly for rice fields compared to other land uses.
The third group includes Lampung Timur, Way Kanan, and Pesawaran.Their test results showed Sig.value < 0.05, t-count > t-table, and f-count > f-table, meaning the hypotheses H1, H2, and H3 were accepted.This implies that rice field area, conversion rate, and their combined effect determine rice production.The combined effect ranged from 83.9 to 95.9% (Table 4).Notably, changes in rice field area and conversion rate do not affect 6.7% of regencies/cities with high rice production and 13.3% with medium rice production.In summary, the rice field area and the conversion rate do not significantly affect rice production in Lampung.Land was once a critical factor in agricultural production, but other determinants now surpass its significance due to technological advancements.These additional factors include natural elements (climate and soil), technology, human resources, and more [43].Moreover, there are constraining factors that reduce production levels.Hayes [5] confirmed that climate change alone affects up to 70% of agricultural production in Yogyakarta.Land suitability for rice farming is also a determining factor because the physical, chemical, and biological soil characteristics that meet plant growth requirements may vary across geographies.Additionally, the analysis was limited to six years due to limited data availability and changes in data collection methods by the Bureau of Statistics since 2019.
Strategies implemented to intensify rice production are not exclusive to Java but extend to Sumatra, as seen in Lampung Province.These strategies aim to reduce the influence of natural factors and enhance anthropogenic role in rice productivity.With limited land resources, intensification has become necessary, for instance, by selecting superior or resistant rice varieties and increasing harvesting frequency.Rice variety determines stem height and durability, which directly impact grain yield.Indonesia predominantly cultivates the Javanica variety, characterized by its distinctive grain shape.This characteristic results in lower yields than the Indica rice commonly grown in East Asia.Increasing harvesting frequency is a strategy to maintain rice production levels even when there are alterations in land use [9].Since 2022, the provincial government has encouraged farmers to harvest four times a year.Adopting rice harvesting tools is also part of intensification, as observed among farmers in Lampung Tengah.
It is essential to recognize that not only rice field area but also land management and suitability, soil fertility, climate, capital, seed selection, fertilization, and irrigation are all factors that shape agricultural production.This multifaceted approach has ensured that most regencies/cities in Lampung Province maintain a food surplus despite substantial fluctuations in rice field area over the last six years.Meanwhile, agricultural intensification is continuously implemented in regencies that depend heavily on rice fields, such as Way Kanan, Pesawaran, Metro City, and Lampung Timur.Properly executed intensification initiatives likely lead to increased rice production.

Conclusion
The conversion rate of rice fields into non-agricultural areas has been found to vary across regions and time.In Lampung Province, the conversion rate averaged 0.12% per year from 2013 to 2018.The lowest conversion rates were observed in the north (2.44% per year) and the east (1.39%).To deal with this issue, the government has been focusing on creating new rice fields in the eastern region, mainly because its geographical conditions remain favorable for rice farming.In contrast, the highest conversion rates were found in the southern (-3.73%), western (-0.67%), and central regions (-0.32%).The southern and central regions have become congested due to urban development, while the geographical conditions in the western region are more suitable for plantations.
The majority of rice fields are concentrated in Lampung Tengah (77,721 ha), Lampung Timur (57,543 ha), Tulang Bawang (51,722 ha), and Lampung Selatan (45,634 ha).This distribution is partly due to their broad administrative areas, with some designated for rice farming.Areas with high rice production in the 2013-2018 period were Lampung Selatan, Lampung Tengah, and Lampung Timur.
In summary, it is generally observed that rice field area and conversion rate in this province do not significantly affect rice production, individually or in combination.Their influence on rice production is mainly seen in Lampung Timur, Way Kanan, Pesawaran, and Metro City.

Figure 5 .
Figure 5. Classification of rice field areas in Lampung Province in 2013 and 2018 Source: BPS-Statistics of Lampung Province, 2014-2019

Table 1 .
Research data and their sources

Table 2 .
located in the lowlands, have abundant water sources, and have been designated as rice production centers by the local government.Lampung Tengah is the province's rice barn; Lampung Timur and Metro City have irrigation networks that provide adequate water for irrigated rice farming.The province's average conversion rate from 2013 to 2018 was 0.12%, indicating an addition of 0.12% rice fields per year in the last six years.The highest conversion rate was identified in Bandar Lampung City (-7.29% per year), while the lowest conversion rate, indicating an increase in the rice field area, was in Mesuji Regency (6.96% per year).In 2018, a significant reduction in rice fields was found in the south and west, where industrial estates were built.Average rice field conversion rates by region

Table 3 .
T-test and F-test results linking rice field area and conversion rate to total rice production by regency/city

Table 4 .
Coefficients of determination (R 2 ) showing the percentage of total rice production explainable by the combined effect of rice field area and conversion rate