Earthworm Communities and Activities in Rice Ecosystem under Different Soil Salinity Levels in Northeast Thailand

Abstract

Soil salinity is one of the most serious agricultural problems. This problem generates low soil productivity and soil ecosystem. Earthworms are one of the most important soil organisms in soil ecosystem (maintaining soil structure and the fertility of soil). Soil salinity has become one of the major determinants of crop productivity in Northeast Thailand. The aim of present study was size and composition of earthworm communities on related soil properties and rice growth under different soil salinity; 2 levels 1) low soil salinity (EC 2-4 dS/m) and 2) moderate soil salinity (EC 4-8 dS/m). Soil and earthworm cast were collected to analyze for soil chemical properties. The results showed that there was significant difference between density and size of different species of earthworms in different level of soil salinity. In rice ecosystem in moderate salt-affected area the earthworm species Drawida beddardi was the only one found at 95 days after rice sowing, while in low salt affected area the earthworm species, Glyphidrilus chiensis and Drawida beddardi were the most common species found at 45 days after rice sowing. Earthworms improve soil properties and rice growth rate. Oryza sativa L. (Khao Dawk Mali 105 and RD6) growth decreased with increasing levels of soil salinity.