Model of Numerical Spatial Classification for Sustainable Agriculture in Badung Regency and Denpasar City, Indonesia

Increasing number and activity of the population to meet the needs of their lives greatly affect the utilization of land resources. Land needs for activities of the population continue to grow, while the availability of land is limited. Therefore, there will be changes in land use. As a result, the problems faced by land degradation and conversion of agricultural land become non-agricultural. The objectives of this research are: (1) to determine parameter of spatial numerical classification of sustainable food agriculture in Badung Regency and Denpasar City (2) to know the projection of food balance in Badung Regency and Denpasar City in 2020, 2030, 2040, and 2050 (3) to specify of function of spatial numerical classification in the making of zonation model of sustainable agricultural land area in Badung regency and Denpasar city (4) to determine the appropriate model of the area to protect sustainable agricultural land in spatial and time scale in Badung and Denpasar regencies. The method used in this research was quantitative method include: survey, soil analysis, spatial data development, geoprocessing analysis (spatial analysis of overlay and proximity analysis), interpolation of raster digital elevation model data, and visualization (cartography). Qualitative methods consisted of literature studies, and interviews. The parameters observed for a total of 11 parameters Badung regency and Denpasar as much as 9 parameters. Numerical classification parameter analysis results used the standard deviation and the mean of the population data and projections relationship rice field in the food balance sheet by modelling. The result of the research showed that, the number of different numerical classification parameters in rural areas (Badung) and urban areas (Denpasar), in urban areas the number of parameters is less than the rural areas. The based on numerical classification weighting and scores generate population distribution parameter analysis results of a standard deviation and average value. Numerical classification produced 5 models, which was divided into three zones are sustainable neighbourhood, buffer and converted in Denpasar and Badung. The results of Population curve parameter analysis in Denpasar showed normal curve, in contrast to the Badung regency showed abnormal curve, therefore Denpasar modeling carried out throughout the region, while in the Badung regency modeling done in each district. Relationship modelling and projections lands role in food balance in Badung views of sustainable land area whereas in Denpasar seen from any connection to the green open spaces in the spatial plan Denpasar 2011-2031. Modelling in Badung (rural) is different in Denpasar (urban), as well as population curve parameter analysis results in Badung showed abnormal curve while in Denpasar showed normal curve. Relationship modelling and projections lands role in food balance in the Badung regency sustainable in terms of land area, while in Denpasar in terms of linkages with urban green space in Denpasar City’s regional landuse plan of 2011-2031.


Introduction
Increase in the number and activity of the population to meet the needs of their lives greatly affect the utilization of land resources [1][2][3]. Land needs for activities of the population continued to grow, while the availability of land is limited, so that there will be changes in land use [4,5]. Besides, the problems faced in the national food nowadays are the degradation of soil fertility [6], the import of rice, the competition of water use is increasing and the agricultural/rural infrastructure is still inadequate and the phenomenon of conversion of agricultural land nowadays.
The objectives of this research are (1) to determine spatial numeric parameter parameter of sustainable agriculture in Badung Regency and Denpasar City (2) to know the projection of food balance in Badung Regency and Denpasar City in 2020, 2030, 2040, and 2050 (3) to set the classification function Numerical spatial in making model of zonation of sustainable agriculture area in Badung Regency and Denpasar City (4) to determine the appropriate model of area to protect sustainable agricultural land in spatial and time scale in Badung Regency and Denpasar City.

Literature Review
Protection of sustainable food crops is a system and process in planning and establishing, developing, utilizing and nurturing, controlling and supervising the sustainable agriculture land of food and its area. Sustainable food crop is one of the government's policies in controlling the rate of conversion of agricultural land, especially rice fields in Indonesia. Sustainable food crops has the objective of (1) protecting sustainable agriculture and food lands, (2) ensuring the availability of sustainable food for agriculture, (3) realizing food self-sufficiency, sustainability and sovereignty, (4) protecting the ownership of agricultural land belonging to farmers (5) improving the welfare and prosperity of farmers and communities, (6) increasing the protection and empowerment of farmers, (7) increasing the provision of employment for decent living, (8)  This will have an impact on local food security, and the subak as a world cultural heritage will lose its existence as an irrigation system in Bali.
In terms of soil and water conservation, Subak has been in use since the seventh century with a semi-technical and simple watering system. Subakrice field also serves as flood control, rainfall catcher, especially located in the upper river. Rice crops as oxygen (O2) contributors on micro and macro scale [9]. The various requirements stipulated in Law no. 41 Year 2009, then should all Subakrice field in Bali need special attention about its existence. The existence of the need for nonagricultural development, such as housing, tourism, shops, industry and infrastructure facilities, limited land conversion is needed, especially in urban areas, government and tourism centers.
The act no. 41 of 2009 on the protection of sustainable agricultural land in Article 9 includes land suitability, availability of infrastructure, land use, technical potential of the land and the extent of the unity of land. The physical condition of the region consists of: the location position of the watershed, irrigation facilities, rainfall, the shape of the region /relief Slope, altitude, rainfall, suitability of agroecosystem lands, conformity to spatial planning and land use, are linked to areas that need to be protected in sustainable food agriculture [

Preliminary Stage
This research activity began from literature study to get initial information about the condition of the research area from previous research results, either in the form of data from reports and maps that already exist. Literature studies was as a reference for field study planning. Preliminary studies include: analysis of data and information from satellite imagery and base maps (roads, rivers, irrigation canals, and administrative boundaries), land use maps, site planning observations. Interpretation of satellite imagery was for tentative landuse map making, area description, surveys and soil making sampling for agro-ecosystem land suitability requirements and for constructing thematic maps of land suitability of agro-ecosystems.

Data Analysis and Interpretation of Satellite Imagery
Interpretation of satellite imagery for the identification, description and classification of land use and landform analysis was done by using three analytical methods: (1) elemental analysis, (2) pattern analysis, and (3) physiography analysis. Element analysis is conducted with nine elements, namely: shape, and size, color and contrast, texture and pattern, shadow, location, and association. These nine elements are used for land use classification. Subsequently, a tentative map of landuse was made before field observation.

Land Resource Data Updates
Data updating focusd on map creation process on a scale of 1: 50,000, such as maps of conformity to regional landuse (strategic protected and conservation areas, agricultural cultivation areas, nonagricultural cultivation areas), land use (irrigated, mixed), watershed (upstream, middle and downstream), irrigation type (technical, semi technical, simple and rain-fed), shape / relief (flat, undulating, hilly and mountainous), slope of origin (> 40% 25-40%, and< 25%), rainfall / agroclimate zone, height (> 500, 100 -500, and <100 m asl), land suitability agroecosystem (S1, S2, and S3), land productivity (5, 2.5 -5 and <2.5 tons / ha / MT) and distance from the city center (> 5 km, 2.5 -5 km, 2.5 km) and minimum area (> 5 ha, 2 -5 Ha and <2 ha). creation by vectorisation of satellite image, watershed area by vectorisation of satellite image, irrigation field irrigation type using spatial data and attribute of subak Denpasar city, rainfall obtained from BMKG Region III Denpasar, agro ecosystem land suitability for paddy rice can be calculated from the results of the sampling point from subakin Denpasar City, land productivity obtained from subak database of Denpasar City and rice field sampling in Denpasar City. The distance from the city center was calculated by buffer method, the minimum area was calculated from the result of spatial distribution of ricefield in Denpasar city in 2015.

Analysis of spatial data and interpretation of Satellite
Collecting and building vector data in Badung regency started with suiting subakrice field with landuse plan by digitizing landuse of Badung Regency in 2013-2033, building landuse data by digitizing satellite image, watershed location obtained from BPDAS UndaAnyar, irrigation system obtained from spatial data and attribute of subak of Badung regency, rainfall obtained from BMKG. The slope data is obtained from the topographical map, the height of the place was obtained from topographic maps. The suitability of agro-ecosystem land for ricefield was obtained from the result of sampling point of subak of Badung regency, land productivity was obtained from subak database of Badung regency and sampling of subak rice field. The distance from the city center is calculated by the buffer method (area) applied, the minimum area was calculated from the result of the width of subak area ofBadung regency of 2013. The data of each spatial per parameter was done by weighting and scoring, then all parameters were overlaid/intersected to combine spatial data values. After the overlay process then total scoring was calculated by calculating feature on the application. Population data in dbf format of overlay results was conducted to determine the class population. Then statistical analysis was done to get standard deviation, maximal, minimum, average and total value. The result of population statistical analysis obtained some modeling obtained from standard deviation [9], by formula: s = standard deviation xi = value of x number-i = average n = number of data Each modeling was analyzed by grouping the data of statistical analysis using select featured expression feature, so get some model that is model 1 to model 5. Each parameter and modeling was arranged with cartography rule with layout feature of composer manager then mappingper parameter in Denpasar and Badung regency as well as zonation map of subak land respectively in Badung regency and Denpasar city.

Establishment of Ricefield Area
The availability of image data in different time periods (2002 and 2015) makaes the land use balance was only calculated for Denpasar City area through overlay -intersect method in QGIS menu. The landuse map was generated from satellite image interpretation. Field check was conducted from the interpretation of satellite imagery for mapping of landuse in 2015.
Analysis of existing ricfield data of 2012 and landuse balance was calculated manually by comparing different year data with the same image data source. Land use classification refers to the National Land Agency classification system. This classification was based on a structured hierarchy, because the classification of cover / land use according to Bakosurtanal (2005)

Criteria Parameter, Classification and Mapping of Sustainable Food Crops
The criteria and mapping of GIS-based PLPPB areas refers to the classification studies, by modifying the weights and scores according to the physical condition of the region [9,12]. Based on the population ring can be made classification of subak land zonasi in some modeling that is:

Food Balance Year 2020-2050 for Badung Regency and Denpasar City
The food balance was calculated based on projected population growth and land conversion. In Badung Regency the food balance is calculated for each Sub-district, while Denpasar city was calculated for whole city.

1) Projected population growth
Population projection is a scientific calculation based on certain assumptions of population growth variable. Population variables include: birth, death and migration, the three components of this variable that determine the size of the population and its characteristics in the future. Calculate the balance of food Year 2020-2050 Kota Denpasar and Badung regency. Calculate the projection of population growth by doing (1) collecting secondary data of Badung regency population per subdistrict, (2) collecting secondary data of population of Denpasar City. Calculating the projection of Badung regency population was done by using Mathematical Method [13]. The 2040 landuse projection is calculated by subtracting the area of urban green area with ten-year land conversion, but if the land area is smaller than the City of Denpasar (12,778 ha) multiplied by 30% or 833.4 ha then the land area in 2040 is 833.4 ha. In the law, open green space is grouped into two, namely private sector (garden / yard owned by public / private) and Public green space (managed and owned by local government). Private gren space by 10% of the total area, while Public green space is 20% of the total area. The projection for 2040 uses public green space by 30%. The land projection in 2050 is calculated by subtracting the projected 2040 results by less than ten years of landuse, but if the land area is smaller than the area of Denpasar (12,

Result of Badung Regency
The results showed that the projection of food balance in Badung regency was in Petang District with productivity of 7 ton / ha, Abiansemal, Mengwi, Kuta Utara and Kuta respectively with   Table 1, and Table 2 listed the data of suitability for rice field area in food balance by modeling in Badung Regency        Table 4 listed the data of suitability of ricefield area in food balance by modeling in Denpasar City.