Spatiotemporal analysis of land use/cover change pattern and population growth in Ngawi Regency

Many factors drive land use and land cover change (LULC) including biophysical and socio-economic conditions. Since Ngawi Regency is one of the areas passed by the toll road, in this study we selected Ngawi as the study area to provide an understanding of the land use/cover dynamics caused by economic factors. This study aims to (1) analyse the distribution of land use/cover change before and after the toll road exists and (2) investigate its relationship with population growth. Data on land use/cover was visually interpreted from satellite imageries (2012 and 2020). Population data was taken from the regional statistics bureau. LULC was detected using a Geographic Information System (GIS). The results show that rice fields dominated land use (44.43% and 42.71% of all existing land use in 2012 and 2020, respectively). A land conversion from a rice field to a toll road has been observed covering 45.45 Ha. Although there was an increase in population from 2012 to 2015, the population number gradually decreased from 2016 to 2020. This result indicates that despite the existence of a toll road, it has less relation to the population dynamic in the study area in which other factors may play a role.


Introduction
Human activity is widely known as one of the main contributors to land use and land cover change.It affects the natural environment and causes disasters and changes in social and economic conditions [1].Humans have modified the environment for thousands of years to meet their basic needs.Over the past two centuries, the impacts of human activity on the earth's surface have grown significantly, changing entire landscapes, and ultimately affecting the earth's hydrological and climate cycles.Rapid population increase, migration, and acceleration of socio-economic activities have intensified changes to the environment over the last few centuries [2,3].These uncontrollable socio-economic human activities cause changes in its use and function [4].
Land is the most efficient resource in the development, where almost all physical development will involve land, such as transportation, agriculture, settlements, forestry, industry, and mining.With increasing human needs, the use of land will also increase, from agriculture to dry fields, from fields to settlements, and settlements to settlements.The factors influencing changes in land use are said to be very diverse, from economic, population, land values, accessibility, number of facilities, and infrastructure [5,6].Population growth, in particular, is known as a factor contributing to land conversion due to the higher demand for settlement and industry area [7].Therefore, defining land use change is an important issue given the long-term impact on the environment.
Spatial perspective studies all phenomena on the earth's surface, both phenomena that occur naturally and phenomena of life and the processes by which these phenomena occur, such as interrelationships, 2 interactions, and even interdependencies between humans and nature or nature and humans.The prior study used spatial analysis for determining the land use changes and evaluating it to the detailed regional planning in Sleman [8].Another study by [9] focused on the dynamics of land cover in Ternate.In different areas, a study [10] attempted to analyze urban expansion with the help of a Geographic Information System (GIS), while [11] gave particular attention to the use of remote sensing for the development of residential and industrial areas, which is also related to disaster [12].There have been studies that used remote sensing data with GIS to extract land cover change information.However, the relationship between land cover change and population growth, especially in the surrounding toll road area is less known.Widodaren sub-district is one of the sub-districts in Ngawi which is passed by toll road.The toll construction began in September 2013 and was completed in November 2018.Therefore, this study aims to analyze the distribution of land use/cover in 2012 and 2020.The objective is also to identify the distribution of land use change and its effect on the rate of population growth in the Widodaren sub-district, Ngawi Regency.Satellite imagery was taken from Google Earth Pro, and a topographical map was obtained from Indonesia Geoportal (https://tanahair.indonesia.go.id/portal-web).Interpretation of remote sensing imagery was carried out using time series images (2012 and 2020) which were then georeferenced and interpreted visually.These steps resulted in land use maps for 2012 and 2020.

Results and Discussion
Figure 3 presents the land use/cover map for 2012 and 2020.It shows that land use/cover in 2012 was dominated by rice fields with an area of 4914.67 hectares or 44.43% of the total land use in the Widodaren sub-district (Table 1).The next land use is forest with a total of 3610.25 hectares (32.64%).Settlement areas covered 837.88 hectares (7.58%), and the last class was the plantation with only 408.48 hectares (3.69%).The agricultural area was largely located in Banyubiru Village with 624.12 hectares or 12.7% of the total area of rice fields in Widodaren.The village with the largest settlement was Sidolaju Village with an area of 108.17 hectares or 12.99% of the total settlement area in Widodaren sub-district.
Land use in 2020 was still dominated by rice fields with an area of 4752,65 hectares (or 42,98% of Widodaren sub-district), followed by forest (3617,88 hectares or 32.71%), and settlements with an area of 879,45 hectares (7.96%) (Table 2).Sidomakmur Village became the area with the largest dominance of rice fields with an area of 604,92 hectares or equivalent to 12.72% of the total area of rice fields in Widodaren.There was a striking difference in the built-up land.In 2020, it shows a toll route, which takes up a land area of 59,06 hectares.This route stretches straight from the north side to the east.On the other hand, ricefields experienced a decrease of 162,02 hectares, equivalent to 3.38% and residential area increased by 41,57 hectares (4.45%).
Figure 4 shows the population of Widodaren District in a period of 9 years (2012 to 2020).According to the table, there was a very high population growth from 2013 to 2014.The population has increased from 71,502 to 76,629 people with a percentage of 7.17%.Meanwhile, from 2015 to 2019 there was a gradual decline in the population.Finally, a big decline occurred from 2019 to 2020 showing several 4,309 people or 5.75% of the population.From Figure 3, we found that land use/ cover in both years of observation was dominated by rice fields.Interestingly, there was a fluctuating number of populations in the 9 years (Figure 4).According to a news report written by https://bpjt.pu.go.id/ about the construction of the Toll Road, the construction began in September 2013 and was completed in November 2018.Supporting the results from [14] and [15], our results showed that the 59,06 ha of toll road construction contributed to the increase in the residential area.Nevertheless, the larger residential area did not correlate to the population growth in the study area.According to [16] who analyzed changes in regional development before and after the construction of toll roads, it was found that there was a decrease in turnover of more than 50% and there were 40 shops out of business.However, restaurants that are referred to by truck drivers have not experienced a large decrease in turnover.It was added that the toll road route is also not profitable for the region that is the driving destination.Considering that the Widodaren sub-district is also passed by the non-toll inter-provincial route, this route has become the main route between provinces.
With the disadvantage of having the toll route for Widodaren District, it does not mean that there are no other ways to seek the welfare of the local population.It is mentioned that population growth is one of the factors driving the new trading area [17].Regional Regulation No. 10 of 2011 concerning Spatial Planning for the Ngawi Regency 2010-2030 stipulates as a regional planning guide.So the dominance of rice fields must be maintained to comply with the spatial plans provided by the government.As such, regional planning needs a spatial approach as supporting data for planners [18].

Conclusions
This study analyses the land use/cover changes before and after the toll construction and also sees its relationship with population growth.Our finding shows that the dominance of land use in the Widodaren sub-district in 2012 and 2020 was rice fields, while the least land use/ cover in both years was plantation.In 2020, it can be seen a new land use/cover from the Google Earth imagery which is the toll road.This toll road stretches straight from north to west intersecting various other land uses.Land use changes mostly occurred in Karangbanyu Village.Changes in land use that occurred in Widodaren District cannot be said to be significant, because the changes not occurred in a large area.This is also supported by population data for Widodaren District from 2012 to 2020.Our observation is that the construction of toll roads does not affect the increase in population.This means that other factors may contribute to the number of populations in the study area.

Figure 1
shows the location of the Widodaren sub-district covering an area of 88.42 km 2 , from 111 o 13'25" East Longitude to 07 o 24'10" South Latitude.The area is in the middle of Ngawi Regency and borders directly with Manting sub-district, Karanganyar sub-district, Pitu sub-district, Kedunggalar sub-district, Jogorogo sub-district, Ngrambe sub-district, and Sine sub-district.The population was 74,993 in 2019 [13].

Figure 1 .
Figure 1.Area of study in Widodaren sub-district.
Figure 2 illustrates the diagram of the research.

Figure 5 6 Figure 5 .
Figure 5 shows changes in land use/cover 9 years from 2012 to 2020.It was observed that the most extensive change occurred in Banyubiru Village with a total area of change of 51 hectares or the equivalent of 25.15%, while the smallest change was Sekaralas Village, namely with an area of 3.44 hectares or the equivalent of 1.7%.Although the area of change is not large, many land changes have occurred in the village.
Hartono H, Machfoedz M M and Setiaji S 2017 Monitoring Land Cover Changes in the Disaster-Prone Area: A Case Study of Cangkringan Sub-District, the Flanks of Mount Merapi, Indonesia In Forum Geografi vol 31 pp 209-19 [9] Rakuasa H and Pakniany Y 2022 Spatial Dynamics of Land Cover Change in Ternate Tengah

Table 1 .
Land use/ cover area of Widodaren sub-district in 2012.

Table 2 .
Land use/ cover area of Widodaren sub-district in 2020.

Table 3 .
Land use/land cover change of Widodaren sub-district in 2012 and 2020.