Using Vermitechnology in Soil Rehabilitation for Rice Production in Salt-affected Area of Northeast Thailand

Abstract

Soil degradation resulting from salinity is a major obstacle to the optimal utilization of land resources. In Northeast Thailand, approximately 17% of the land is salt-affected due to salt bearing rocks, predominantly in Nakhon Ratchasima, Khon Kaen, Roi-Et and Mahasarakham provinces. The present extent of salt-affected soils in the Northeast already substantially restricts crop production in many areas especially rice production. This study aims to study using vermitechnology to rehabilitate saline paddy soil for rice production. The experiments were conducted to study the influence of earthworm and their activity on soil properties, production and growth of rice variety (Pathumthani 1) under the influence of salt. The results found that Activities of earthworms encourage the release of available plant nutrient, especially when associated with the utilization of organic matters. Applying 1% of biochar per 1 kg of dry soil, 650 kg of rice straw per Rai, and 1,000 kg of vermicompost per Rai can significantly increase organic carbon in soil in deteriorated paddy soil (EC= 0.08 – 0.13dS/m), slightly saline paddy soil level 1 (EC= 1.56 – 1.71 dS/m), and moderately saline paddy soil level 2 (EC= 2.90 – 3.47 dS/m). Moreover, the amount of total nitrogen, exchangeable sodium, exchangeable calcium, and exchangeable magnesium in soil also increased under all soil salinity level. The experiment under control condition indicated that activities of earthworms associated with the utilization of biochar, rice straw, and compost produced by earthworm enhanced the availability of plant nutrients. Furthermore, earthworms are soil organisms that benefit to soil property rehabilitation such as improving physical properties of soil by assisting on soil inversion. The burrowing by earthworm loosens the soil causing well drainage and aeration and improving water holding capacity. Activities of earthworms associated with the utilization of biochar, rice straw, and vermicompost in different soil salinity level under control condition enhanced growth rate of rice that increases rice productivity.