Effects Of Rice Frog Co-Culture On Soil Ecology Of Rice Paddy,Rice Growth,Yield And Quality Traits

Rice production generally requires a large amount of pesticides to control pests and diseases,and also needs to invest in a large number of fertilizer to supply the system’s nutrient,thus leads to the low biodiversity and highly vulnerability of the paddy ecosystems,repeated outbreaks of diseases and pests occur,ultimately it will cause ecological,environmental and food safety problems.With the rapid improvement of China’s economic and living standards,people are having increasing demands for green organic foods which shows a certain prospect for paddy ecology development.Therefore,this study explored the effects of Rice-Fogs co-culture,by introducing predators Rana tigrina cantor into rice paddy systems,the rice yield,quality and soil microbial community were analyzed.In this study,two rice varieties,Meixiangzhan 2(aromatic rice)and Huanghuazhan(non-aromatic rice)were chose,and two integrated culture mode rice monoculture(RM)and rice-frog co-culture(RF)were separately set up.The rice-frog co-culture,three densities were set:3 frogs/m~2(RF3),6 frogs/m~2(RF6)and 9 frogs/m~2(RF9).A total of 8 treatments,3 repetitions were set,using a completely randomized block design.The effects of rice-frog co-culture on agronomic characters,yield and composition factors,rice quality,rice field pests and physical and chemical properties of paddy soil were studied,and the effects of the main component of the aroma2-acetyl-1-pyrroline(2-AP),its synthetic precursor and related enzymes were also analyzed.The results are as follows:1.There was no significant change in the content of total nitrogen,total phosphorus and total potassium in the field.The contents of organic matter,alkali nitrogen,available phosphorus and available potassium under rice-frog co-culture was better than the RM treatment at the maturity stage.There was significantly difference on soil microbial community composition and structure between rice-frog co-culture and rice monoculture.2.Rice-frog co-culture improved soil nutrient content,increased the height,tillering and leaf chlorophyll content,improved the net photosynthetic rate.The rice-frog co-culture has obvious control effects on rice leaf roller and rice plant hopper at the rice heading stage.3.The number of effective panicles and yield of rice is significantly improved in rice-frog co-culture,and the seed setting rate,the grain number,effective panicle number and other yield indicators are also increased.Rice-frog co-culture can significantly improve the brown rice rate,polished rice rate and whole milled rice rate and under RF6 treatment the effect is the highest;Rice-frog co-culture also improved the nutritional quality of rice,F6 treatment in Meixiangzhan 2 produced a most significant increase in protein content.4.Rice-frog co-culture can significantly increase the content of aroma 2-AP in aromatic rice,and the formation and accumulation of 2-AP is related to proline,pyrroline-5-carboxylic acid,soluble protein,and the improvement of proline dehydrogenase activity,pyrroline-5-carboxylate synthase activity,and ornithine transaminase activity.The content of 2-AP accumulation was the highest in the RF6treatment.5.In summary,the new culture mode about fragrant rice cultivation and rice-frog co-culture is the combination of"increasing production","increasing the aroma"and"controlling pests"mode.This study shows the breeding of 6 frogs/m~2(RF6)was the optimal density.The relevant results of this study can provide scientific guidance and practical basis for the extension and application of aromatic rice co-culture and paddy field ecological model.