Karakteristik fiska dan mekanika pada berbagai jenis tanah

Abstract

Soil physical properties, as well as biologrcal and chemical propwties, affect crop production and growth in relation with water availability and physical environment for plant g~owth. Also, mechanical properties of soil become important in agriculture for learning the soil carrying capacity for agricultural machinery and its effect toward rooting environment. This reseacl~ was conducted with the objective of learning the basic physical, hydraulic and mechanical properties of various types of soil and studying their interrelations with soil colloid. Research method comprise soii sampling in the'fie!d &om various locations in West Java, Central Java and South Sumatra. Analysis of physical, chemical, mineralogical and rnechanicai properties of soil with standard rnethd, was conducted in laboratory of Department of Soil Science, Faculty of Agriculture and Department of Agricultural Engineering Faculty of Agricultural Technology, Bogor Agricultural University fiom January to September 2003 Result of this research show that physical and mechanical properties of each soil type studied, differ from each other. The studied soils have textural classes sandy loam. loamy sand, clay, silty clay and clay loam. Soil with coarse textural class (sandy loam and loamy sand) had buld density ( I . 18 - 1.30 gr/crn3) higher than those of clay textured soit, lower total porosity (5 1.73 - 52.24%), very low Coefficient of Linear Extensibility (COLE) (0.005 - 0.001), Index of aggregate stability (IS A) ranging from very unstable to stable (39.55 - 54.47) and permeability ranging from rapid to very rapid (12.56 - 25.18 d o u r ) . Content of available water in this soil is very low (2.5 - 3.0%) Soil with medium textural class (clay loam) had lower bulk density (0.53 - 0.66 gr/cm3) as compared with bulk density of common m i n d soil, h&er tad porosity (74.30 - 78.58%) as ascompared with clay textured mil (24.5 1 - 68.16%), very high values of COLE (0.268 - 0.353). aggregate stability with ranged from very unstable to stable (32.56 - 4830) an permeability class with was somewhat rapid ( 8.87 - 10.23 cm/hour) . Content of available water in this soil is vw high (32.6 - 35.4%). Soils with clay textural class clay, silty clay and silty clay i loam) had higher bulk density (0.83 - 2.02 gr/cm ) as cumpared with medium textured soils (0.53 - 0.66 gr/cm3). COLE values ranging b m low to very high (0.020 - 0.366), aggregate stab&@ ranging fiom very unstable to very stable (3 1.44 129.551, and permeability ranging h m very slow to modemrely rapid (0.04 - 1 1 -39 cmm0ur)- Available soil water ranged liom very low to very high (3.0 - 26.5%). Most of the mils studied, had kaolinitic clay mineral. Podsolik soil of Jamga and Grumusols had smdte clay miad w h m other types of soil had mixed clay minerd (Planowl of Serang, Alluvial of Kmwang, Muvial of Brebes and Medireran of Ciampea). Soil with medium textural class (Andosd) were dominated by Allophane mineral.