Geospatial Analysis of Abandoned Lands Based on Agroecosystems: The Distribution and Land Suitability for Agricultural Land Development in Indonesia

The Indonesian land area is 191.1 million ha, part of which is abandoned land in various agroecosystems that have the potential for expanding the agricultural area. The purpose of this research was to geospatially analyze abandoned land based on its agroecosystem at the national and district levels, as well as to evaluate the land suitability of the land for expanding agricultural development. The methods included: (1) geospatial analysis of the national land cover map at a scale of 1:250,000 combined with soil and climate information to identify abandoned land and examine its agroecosystem, (2) selecting representative districts in each agroecosystem for visual interpretation using high-resolution imagery, i.e., SPOT 6/7, (3) assessing the land suitability of abandoned land for agricultural development at the national and district levels, and (4) predicting national abandoned land and its land suitability. The essential finding is the identification of abandoned land at around 42.6 million ha in Indonesia distributed over six agroecosystems, with the widest being in dry lowland and wet climates. Then, 54 districts were selected to characterize abandoned land by using SPOT 6/7 high-resolution imagery and were interpreted visually. It was found that the abandoned land covered approximately 16.9 million ha. The distribution of abandoned land from the interpretation of satellite imagery was smaller than that of geospatial analysis due to differences in the map scale and the use of ancillary data. The identification of abandoned land from high-resolution imagery should be carried out for all regions of Indonesia to accurately map the distribution of the abandoned land and characterize the properties. However, it requires a large amount of time, cost, and facilities to complete the inventory. The geospatial analysis that combined imageries and ancillary data identified 27.7 million ha of abandoned land suitable for expanding the agricultural area. The largest suitable abandoned land for the purpose was found in the lowlands with a wet climate, especially in Papua, Kalimantan, and Sumatra islands. The identified suitable abandoned land of 54 districts differed by scale, in which it was 11.2 million ha at the scale of 1:250,000 and 8.5 million ha at the scale of 1:50,000, respectively. The potential land expansion for food crops, particularly paddy fields, was only 2.2 million ha, located in mineral swamp land, which was predominantly located in Papua, with inadequate accessibility. Expanding paddy fields for national food security in the future would be constrained by less suitable land resources, while the near future challenge is the competition of land allocation for agricultural and non-agricultural sectors, as well as for food crops and plantations.