Methodology Development for Land Degradation Level Identification in Dryland for Utilization of Abandon Land for Agricultural Purposes

Abstract

Land degradation is a serious threat for dry-land agriculture. It is urgent to develop standard methods to identify degradation level which is accepted by all institutions related to degradation inventory in Indonesia. The research objectives are : (I) To develop methodology for identification of land degradation levels in dryland for reconnaissance and semi-detail scales; (2) To draft manual for land degradation level inventory in dryland for reconnaissance and semi-detail scales. This study area comprised of three sub districts i.e. 1) Babakan Madang subdistrict, 2) Sukamakmw subdistrict, and 3) Cigudeg subdistrict of Bogor Regency, West Java. Observation and assessment of characteristics was sampled for key region detennined based on its accessibility and its representativeness on degradation levels. There are five categories of land degradation intensities (lahan kritis) which are highly degraded, degraded, slightly degraded, potentially degraded and not degraded Discriminant function analysis was then employed to identify significant variabel determined degradation level and cluster analysis to clustered each sample. Assessment on land degradation established by Ministry of Forestry and Estate showed that percent-correct of classification as much as 51,67%. It was indicated that grouping classes required for next assessment, therefore fiom five groups of land degradation there were grouped into three groups: (1) Not degraded soil, (2) Potentially or slightly degraded grouped into slightly degraded and (3) Degraded and highly degraded grouped into degraded soil. Clasification into two groups of land degradation were (1) Not degraded soil consist of degraded and slightly degraded and (2) degraded soil. Reclasification based on three classes resulted 75% percent correct of clasification, while two classess of degradation resulted 86,68% correct classification. Temporary result shows that variables for land degradation indicators on reconnaissance inventory were erosion symptoms, conservation practice and solum depth. Variables for semi-detail land degradation inventory were all visual variables and all physical and chemical properties such as CEC, base saturation, Hidrogen exchanged, and soil texture. Range of characteristics were not determined yet due to instability result of importance variables fiom different result analysis.