All plots used in the experiments measured about 650 m2, and had a rice field area (550 m2) and a 1 m deep L-shaped trench (100 m2) that serves as a fish refuge. All plots were surrounded by a dyke, and had their own water in- and outlet.
All plots used in the experiments measured about650 m2, and had a rice field area (550 m2) and a1 m deep L-shaped trench (100 m2) that serves as afish refuge. All plots were surrounded by a dyke, andhad their own water in- and outlet.