Changes in soil morphology and properties under long-term soil management in humid tropical regions of Lampung, Indonesia

A humid tropical climate is characterized by high amounts of rainfall and high temperatures throughout most of the year. It results in elevated rates of soil weathering, soil loss, the leaching of cations, and the oxidation of the organic matter in the soil. The aim of this research was to observe the changes in soil morphology and soil properties due to the differences in soil management over a period of 20 years. Three types of soil management methods were applied, namely, intensive tillage (IT), minimum tillage (MT), and no tillage (NT). Basically, minimum tillage and no tillage are types of conservation tillage (CT). The results showed that, with IT management, the lower content of organic matter in the upper layer of the soil caused the soil to become lighter in color, which was characterized by higher chroma. The soil structure on the top layer of the soil changed from crumbs toward angular blocky. The topsoil was seen to be more friable than when the other two management methods were applied, while the lower layer was denser or more compact. Generally, the chemical properties of the soil with the CT management methods were better than those with the IT method, and those with the NT method were slightly better than those with the MT method.