Abstract
Although there has been a high interest to investigate the relationship between climate and crop yields in Indonesia, little evidence is available for crops in highland of the country. This study evaluates the relationships between global climate indices (Southern Oscillation Index, SOI; sea surface temperature, SST) and rain-fed crop yields in Gunungkidul district, highland of South-Central Java. Principal Component Analysis (PCA) approach was used to summarize the averaged SSTs during planting season for the El Niño monitoring regions: IOBW (Indian Ocean Basin-Wide), Niño.West and Niño.3. Crops yield of each sub-district of the area was detrended using a 5-year moving average to enhance reliability of the data. For some sub-districts, the first principal component of SSTs was negatively correlated to crop yield residuals of corn and soybean while SOI was positively correlated to that of corn and dryland paddy.
