Agricultural Land Use Change in Tsirang

Tsirang Dzongkhag

Geo-Inquiry: How has agricutural landuse changed in Tsirang?

Agriculture is the main backbone of the country in Bhutan: more than 70% of its population depends on farming for their livelihood and youths are persistently supported by the country to takeover it as the part of employment. Especially in the Tsirang district, many youth take agriculture as a part of employment and produce good harvest comparing to other districts. However, the production varies from gewog (block) to gewog owing to topographical features, soil fertility, water and road connectivity to farm. Therefore, this study intends to examine the changes in the agriculture land use in Tsirang using the GIS and the LULC 2000 and 2016 datasets.

Out of 12 gewogs under Tsirang district, five gewogs revealed the highest agriculture land use in the year 2016 viz Kilkhorthang, Tsholingkhar, Gosarling, Semjong and Phuentenchhu. Similarly, Patakha, Bunglegang, Rangthangling, Mendelgang, Barzhong, Betini, Tsirangtoe and northern part of Phuentenchhu showed least agricultural changes over the years. The increased agriculture land used patterns are attributed by the suitable topographical features, soil fertility, and access to water and road connectivity and proximity to town. Likewise, least agriculture land use changes are attributed by the stiff slope, encroachment of wild animals and poor road connectivity. This study served as a reference to policy makers, agriculturist and forester to evaluate the impact of human-wildlife conflict and the allocation of budget to uplift the agriculture practices in least cultivated gewogs.

Materials & Methods

For the land use and land cover change analysis, two years, 2000 and 2016 land use land cover dataset was used to map the study area. The idea was to detect the change in, and status of, land use cover and the changes that have taken place, particularly in agricultural land, over the period using ArcGIS.

LULC 2016 data has more added features with three classifications of agriculture, namely chhuzing (wet land), kamzhing (dry land) and orchards. The LULC 2000 data has agriculture in general inclusive of all types of agricultural land. In order to have same output, classification of 2016 agricultural data was necessary to match with 2000 LULC data.

Step 1: LULC data 2000/2016 was loaded in ARC GIS and added dzongkhag shape file. Tsirang Dzongkhag was selected from table of attribute and exported and clipped through geoprocessing tool. LULC data of Tsirang Dzongkhag was acquired through extract by mask. Map properties were edited in Subfield values as subclass field under symbology. Feature to raster in search button feature was used to convert the data from feature to raster. Feature to raster cell size was kept as 30 to main accuracy. The level of detail (of features/phenomena) represented by a raster is often dependent on the cell (pixel) size, or spatial resolution, of the raster.

Step 2: To detect land use and land cover (LULC) change from multi-band and multi-temporal raster imageries, image interpretation and classification process is computed (Li et al. 2014).The LULC data was reclassified for 2016 LULC data to have comparable output. LULC data was reclassified by having same value for Chushing, Kamshing and Orchards since these are categories of agriculture in Bhutan. The values for rest of the features were kept unchanged as it would make any difference to agriculture land use changes.

Land Use Comparison

There is an increase in the agriculture land use in the year 2016 as compared to the year 2000.

Tsirang has both locational and seasonal advantage. It falls near to the border area of fertile land. Tsirang is centrally located and is well connected to most of the dzongkhags for market. Tsirang has idle weather condition for settlement and agriculture. Tsirang dzongkhag has experienced an increase in population size by about 4,183 persons during the intercensal period, a growth of 22.4% between 2005 and 2017 (PHCB,2017).

Subtantial increase in agricultural land could be seen in year 2016 compared to 2000 as indicated images on the left. Use the buttons on the image to navigate between the years. The increase may be due to the gentle weather, each summer and winter vegetable is grown fine within the district. Tsirang dzongkhag has a seasonal advantage in terms of vegetable production over alternative dzongkhags. Farmers of Tsirang take fresh local vegetables to Thimphu centenary farmers Market and other dzongkhags. The locally grown vegetables are grown organically which has led to increase in demand for vegetables. This has contributed as motivating factor for farmers to practice agriculture extensively.

The gewogs with the highest agriculture land use in the year 2016 as shown in figure 7 are Kilkhorthang, Tsholingkhar, Gosarling, Semjong and Phuentenchhu. Figure 8. topographical map of Tsirang shows topography of highest agriculture lands in Tsirang. These places are have gentle slope added with greater advantages of nearness to water source, good road connectivity and nearess to Damphu town.

The least agricultural changes were seen Patakha, Bunglegang, Rangthangling, Mendelgang, Barzhong, Betini, Tsirangtoe and northern part of Phuentenchhu. These places are located in the outskirts of the main town. These places are near to the forested area where wildlife conflicts are recurring issue. Moreover, Barshong and Patakha are located along the river cliff where agriculture practice is difficult. Tsirangtoe is a hilly area and thus has sloppy agricultural lands which are prone to soil erosion.

In the present study, visual assessment of LULC change was carried out using maps derived from Land use land cover datasets and using digital image processing techniques. Analysis revealed that agricultural areas increased during the years 2000–2016. The increase was significant. Most increase was seen in the gewogs of Kilkhorthang, Tsholingkhar, Gosarling, and Semjong. The increase could be due to the availability of fertile soil and favourable climate, Tsirang dzongkhag is considered agriculturally most productive. Every year, the agriculture production has increased. The land use land cover map show much changes in the agriculture land use between the years, 2000 and 2016. In the year 2020, Tsirang produced 3300 MT of vegetables and aims to produce 3800 MT of vegetables and fruits and other agricultural to supply to the western dzongkhag. (Yuden, February 1, 2021)

Findings and Limitations

The study on the changes in the agriculture land use using the two dataset of Land use land cover of years 2000 and 2016 of Tsirang Dzongkhag showed increase in the agriculture land use between the two years. The study found out that, in the year 2016, there was a greater area under agriculture. The agriculture land use would increase even more in Tsirang in future. With ban in all the vegetables, Tsirang will become the leading dzongkhag in the production in the country, thus helping the country to reduce imports of vegetables and to achieve food security in the country. The findings of this project can be helpful for systematic assessment of land and water potential, alternatives for land use and economic and social conditions in order to select and adopt the best land-use options. Its purpose is to select and put into practice those land uses that will best meet the needs of the people while safeguarding resources for the future.

However, there are several limitations of the study. We couldn’t get the land use land cover dataset of the year 2020 or 2021 to show the latest changes happening in agriculture land use. Additionally, as the LULC datasets were classified using different techniques, direct comparison between the two products must be taken with consideration.

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