Analysis of Agricultural Land Use Changes in Jombang Regency, East Java, Indonesia Using BFAST Method

Jombang is one of the regency in East Java province which is dominated by agricultural lands. This is caused by high levels of soil fertility due to volcanic eruption in the past. Recently, conversion of agricultural land to non-agricultural land has been increasing as accelerated by the growth of industrial sector. If this conversion occurs continuously, it will lead to decreasing of the agricultural production in Jombang. Therefore, it is an urgent to provide accurate and up-to-date information of agricultural land use changes. This research will investigate the temporal vegetation dynamics in paddy fields and to detect their changes in Jombang Regency. The Breaks For Additive Season and Trend (BFAST) method was used to identify the change pattern events in this study. This method can estimate the time and amount of the abrupt change in the time series datasets. Based on the temporal vegetation pattern, the agriculture land use in Jombang could be categorized into ten typical cropping patterns, namely: paddy-paddy-paddy, paddy-paddy-secondary crops, paddy-paddy-bareland, paddy-secondary crops-bareland, paddy-secondary crops-paddy, paddy-bareland-paddy, forest, sugarcane, non-agriculture, and mixed vegetation. Moreover, the results show that by the BFAST change detection, the change distribution of agriculture land use from the past ten years can be detected.