Variability of Maize Yield Over Different Soil Types and Land Suitability Indices In The Humid Tropics, South Sulawesi Indonesia

Abstract

An attempt of understanding the influence of land characteristics on crop yields is useful in designing site specific management of land resources. Characteristics of soil and climate in the humid tropics like Indonesia vary considerably among agroecological zones.   The primary aim of this study is to assess the correlation between land characteristics and maize yields; and to evaluate the variability of land index over different soil types in the humid tropics of South Sulawesi, Indonesia.  As many as 30 soil profiles were made at study area within fourteen different soil types with traditional maize cultivation. A linear regression with Pearson correlation analysis was undertaken to evaluate maize yields at different soil and climate characteristics.  It was found that soil pH, base saturation, and organic carbon have a significant correlation with maize yield with R² value of 0.705, 0.741, and 0.683, respectively.  The analysis also shows that correlation between land suitability index and maize yield reaches an R² value of 0.807.  The scatter points in the diagram depict a good indication that the higher the land index the better maize yield can be produced in the area under consideration.  Suitability analysis indicates that land suitability index (I) value ranges from 11.5 to 55.0, with  maize yield from  1.6  ton/ha (Typic Dystrudepts) to 5.2 ton/ha (Typic Haplustalfs) and parametric suitability classes are S2 (moderately suitable), S3 (marginally suitable), N1 (currently not suitable), and N2 (permanently not suitable).

Keywords: Land suitability index; humid tropics; maize; South Sulawesi