| 摘要 |
FIELD: agriculture, in particular, production of fish settling material on rice checks of irrigation system. ^ SUBSTANCE: method involves leveling surface of check; deepening discharge channels to 1.5-1.7 m depth with gradient toward discharge construction; flooding check; settling fish larvae in check on the second-third day after flooding; providing fish larvae keeping procedures; discharging water from check and catching young fishes. Phytophagous fish larvae, mullet and heat-loving American buffalo fish larvae are settled in check. Undersized 4-day aged and grown one-day aged white carp larvae, grown 14-18 day aged carp larvae are used for stocking. At fish settling density of undersized white carp larvae of (40-74).103 sps per hectare, grown white carp larvae of 13.103 sps per hectare, and carp larvae of (15.3-30.0).103 sps per hectare, fish larvae are kept in check at water temperature of +23 - +28 C, with temperature being increased at stable gain in weight of this year's brood to +34 C. Hydrologic growing mode in checks is maintained with water layer thickness of 0.12-0.20 m. Vegetative period of growing of this year's brood is 85-95 days. Young fishes are caught during third decade of September. With two-year selection of growing carp in adjacent rice checks, spawning of young fishes is provided, followed by growing of spawn and fattening of young fishes. Wintering is provided in irrigation channel. Settling of larvae in check is conducted with the use of one or two nests and carp as sire. Each nest includes one female and one or two males. For growing of young fishes, 15-day aged 0.3-0.5 g weight fries are settled and additional settling is provided so that fish density reaches 1000 sps per hectare; in case 40-day aged 5-10 g weight fries are settled, density is reduced to 600 sps per hectare. One-year aged mullet fishes of 30 g weight are settled in prepared checks for fattening with density of 250 species per hectare. In prepared checks for fattening of white carp and sheatfish, one-year aged 50-70 g weight fishes are used at density of 600-800 species/hectare and later transferred into discharge channels. In case rice checks prepared for "water steam" are to be stocked, fish larvae settling norm at average weight of carp of 50 g is set to be between 1000 and 1200 sps per hectare and of white carp having weight of 120-140 g to be set between 50 and 60 sps per hectare at hydrologic check mode of at least 0.45-0.50 m thick water layer. Method allows fish productivity of ponds to be increased to 0.2-0.3 t/hectare. ^ EFFECT: increased fish productivity and rice yield in checks, keeping of soil fertility and improved ecology control. ^ 11 cl, 6 tbl, 9 ex |
