Effects Of Crayfish Activity On Paddy Field Environment In Rice-crayfish Coculture

Comprehensive planting and breeding of rice fields is an efficient ecoagricultural model for aquaculture economic animals while growing paddy rice.At present,rice-fish coculture,rice-crab coculture,and rice-duck coculture are not perfect,and further studies are needed.Especially for rice-crayfish coculture,due to its rapid development in recent years,the scale expands unceasingly,at the same time because of crayfish eats miscellaneous fast growth,good dig holes,etc.,with the interaction between rice and paddy environment needs to be further studied.In this study,a 2-year rice-crayfish coculture field experiment was conducted to set up different C/N feeding patterns and comparisons of different rice planting densities.Soil,water,and rice photographs above the traps at different growth stages were collected and combined with crayfish traps.The amount of catch,growth of rice,and crayfish production are designed to answer the following questions:(1)How are crayfish distributed in paddy fields?(2)What factors influence the distribution of crayfish?(3)How did the crayfish activity affect the paddy environment? The study has achieved the following main results.1.Activity of crayfish in rice fields and its influencing factors?Rice leaf gap,rice planting density,ring ditch setting,different C/N feeds,etc.will all affect crayfish activity.From the catch size and field statistics of crayfish,we can see that:(1)The catch of crayfish on the edge of paddy field platform is significantly higher than that of paddy field(P<0.05);(2)The distribution of crayfish is positively correlated with the leaf gap of rice;(3)The catch size of crayfish of the rice planting density 32cmx16 cm group was significantly lower than that of rice(32cm x 24 cm and 32 cm x 32cm)(P<0.05);(4)Crayfish had the highest catch traps in C/N was 12 groups(feed + bran group);(5)Crayfish fed the feed group The number of caves was significantly higher than that of the dietary bran group(P<0.05)and the dietary bran group(P<0.05);(6)The crayfish production was highest in the dietary bran group.2.Effect of crayfish activity on paddy field environment?The rice-crayfish coculture beneficial to the improvement of soil fertility and needs further improvement.Compared with the rice monoculture group,the ricecrayfish co-culture group reduced soil compaction.Compared with the initial period of the experiment,(1)the ammonia-nitrogen content in the rice-crayfish coculture(feed + bran + sugar)decreased by 35.52%,reaching a significant level(P <0.05);(2)Total decline in soil total phosphorus in rice-crayfish coculture;(3)The soil organic matter in four treatment groups showed an upward trend,and the increase in soil organic matter content in rice-crayfish coculture was higher than that in the rice monoculture;(4)The soil organic carbon in four treatment groups declined overall trends showed that the decline in soil organic carbon in the rice-shrimp co-authoring group was higher than that in the rice monoculture group;(5)The soil urease in four treatment groups showed a decreasing trend overall.Among them,the rice-crayfish coculture group(feed + bran)and rice-crayfish coculture(feed + Bran + sugar)reached significant level(P <0.05);(6)Dehydrogenase of dietary bran sugar group increased significantly(P <0.05);(7)At the end of the experiment,the soil alkaline protease was significantly reduced by 71.88%(P<0.05)in rice-crayfish coculture(feed + bran + sugar);the soil cellulase in the dietary bran group increased significantly by 22.59%(P<0.05).The rice-crayfish coculture has a certain ecological effect of reducing environment pollution.The water indexes(ammonia nitrogen,nitrate nitrogen,nitrate nitrogen,nitrite nitrogen,total nitrogen,and total phosphorus)in four treatment groups showed a high initial concentration,followed by a rapid decline,tending to a stable trend,and there was no significant difference between treatment groups(P>0.05).