Chairman
"If we introduce organic farming by using mud snails, we can raise crop yields while economizing on much labour and agro-chemicals."
Application of the organic agriculture with the freshwater snail Pomacea canaliculata is an important way to increase rice yields while not using herbicides and chemical fertilizers at all and is of great significance in protecting the soil ecological environment.
We have studied the possibility and saline soil remediation effects of using P. canaliculata snail in tidal flat paddy field, and has achieved many successes in this research field.
The most important problem of the application of organic farming using P. canaliculata snail is to ascertain the possibility of the survival and the breeding of the snail in saline paddy soil, and to answer a question of "can the weeds growing in tidal flat paddy field become food for the snails?".
From the results experiments, it can be concluded that the snail can safely survive and grow in tidal flat paddy fields with a salinity (i.e., Cl− concentration) of less than 0.15% which is the salinity limit for rice growth.
Furthermore, the results have shown that the weeds such as Enteromorpha linza, Cyperus amuricus Maxim, and Monochoria korsakowii in the tidal flat paddy field were removed, which indicates that the weeds can become food for the snail.
The effects of the application of organic farming using the snail on the amelioration of the tidal flat saline soil and the improvement of the soil fertility were investigated from the field experiments.
The snails' activities for survival in the paddy field lead to the improvement in the physical and chemical properties of the saline paddy soil.
The removal of weeds by the snails' activities and thus clearing the water in the paddy field can result in a favorable condition for the growth of rice roots by increasing the percentage of sunshine on the soil and the soil temperature.
Scratching the upper mud layer and increasing the soil porosity by the horizontal and vertical movements of the snails lead to an increase in the permeability and aeration of the soil.
A large amount of the snail shells that contain calcium carbonate (CaCO3) is accumulated in the soil and these shells are gradually decomposed by chemical and biological processes, which leads to in an increase in the Ca2+ content in the soil and triggered the replacement of excess Na+ from the cation exchange complex. As a result of the decrease in sodium (Na+), the physical and chemical properties of the soil are considerably improved.
Part of snail excretion stimulates the rice growth during that year by supplying different nutrients to the soil, while the others are accumulated into the soil for increasing the humus matter and nutrients, which leads to a continuous improvement of the soil fertility.
It can be seen from the results of the field study that the application of organic farming using the freshwater snail creates a favorable condition for the rice growth, and leads to a 9-10% increase in the rice productivity when the fertilizer is applied as before, while a 2-3% increase when only a 50% of the previously applied fertilizer is applied.
These results have been reported in the paper entitled "Possibility and effects of using Ampullaria tischbeini (Dohrn) snail in saline paddy field" (https://doi.org/10.1007/s13165-017-0200-z), published in the journal "Organic Agriculture".
