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Possibility and effects of using Ampullaria tischbeini (Dohrn) snail in saline paddy field

Jong-Song, Jo, Song-Ho, Pak, Song-Ok, Cha
Organic agriculture 2018 v.8 no.4 pp. 335-347
calcium, chlorides, exchangeable sodium, excretion, field experimentation, grain yield, herbicides, infiltration rate, mineral fertilizers, nutrients, organic production, paddies, paddy soils, porosity, saline soils, salinity, shell (molluscs), snails, sodium, soil fertility, soil organic matter, soil physical properties, soil remediation, sowing, texture, weeds
The main objective of orientation towards organic farming is to improve crop production and soil fertility. Organic farming using an Ampullaria tischbeini (Dohrn) snail in a saline paddy field not only limits the use of chemicals such as chemical fertilizers and herbicides but also improves the physical, chemical, and biological properties of the soil. The snail can survive in both non-saline and saline paddy fields. The results of the laboratory and field experiments show that the snail can survive in paddy fields with Cl⁻ concentrations of 0.15% or less (hereafter referred to as salinity). At the end of June (40–45 days after sowing), 2600–3300 snails per hectare are released to a saline paddy field. Artificially released snails not only remove almost all weeds but also improve the chemical, physical, and biological properties of the paddy soil. In the paddy soil, lots of calcium ions (Ca²⁺) are produced by the decomposition of dead snail shells. Calcium is required for saline soil remediation, as it will displace sodium and reduce the exchangeable sodium percentage. In the paddy field, the snail movements lead to an improvement in soil physical properties such as texture, water infiltration rate, and porosity. Furthermore, the snail excretions lead to significant increase in soil organic matter content and nutrients. In the saline paddy field with snails, rice yield was higher than that in the control plot (with no snail).