EFFECT OF LONG-TERM CASSAVA CULTIVATION ON THE MORPHOLOGY AND PROPERTIES OF SOILS IN LAMPUNG, SOUTHERN SUMATRA, INDONESIA

Abstract

Cassava is easily cultivated and very tolerant of various soil conditions. It can be planted
almost anywhere, in various types of soil, even in marginal soil where other food crops are difficult to grow
properly. However, imposing higher productivity for two decades clearly reduced the quality of the soil. The
aim of this study is to determine the influence of long-term cassava planting (> 20 years) on the morphology
and properties of the soil, compared to mixed gardens which were rarely tilled, at 14 test sites in 10 locations
in Lampung, South Sumatra, Indonesia. Cassava cultivation over a period of more than 20 years was seen to
make the soil color brighter in both layers of soil which, in turn, affected the other soil properties. Cassava
cultivation for more than 20 years caused the surface horizons at half of the test sites to change from crumbs
to angular blocky and granular. The physical properties of the soil that was cultivated with cassava
plantations for more than 20 years did not differ significantly from those of the mixed garden soil which was
rarely tilled. However, a tendency was seen for the water available pores (WAPs) to decline. Cassava
cultivation for more than 20 years greatly reduced the soil organic carbon (at a critical value of 0.01) and
significantly reduced the soil pH, soil-CEC, and exchangeable bases (at a critical value of 0.1). However, the
long-term cultivation of cassava did not affect the base saturation, although there was a change in the number
of exchangeable bases and the CEC of the soil.