Environment Economic Effect And Its Mechanism Of Rice-turtle-fish Symbiosis System

In this paper,we disscussed a ecological breeding symbiosis system of rice-turtle-fish.By means of environmental economics,the differences in rice growth and development,environmental effects and environmental economic benefits of rice-turtle-fish（RTF）,rice-turtle（RT）,rice-fish（RF）and rice single cropping model（RM）were compared and analyzed in order to explore the environmental economic effects and mechanism of the rice-turtle-fish symbiosis system.The results as follows:（1）The ricr-turtle-fish symbiosis system can promote the growth of root,forming strong lever effect,enhance the yield of rice.In the root character,the total root length,single root length,root volume and root dry matter of RTF,RT and RF models were significantly higher than that of RM model.The root activity of RTF,RT and RF at the tillering stage was28.91%,79.50%and 15.09%higher than that of RM model,respectively.The stem diameter,bending moment and single stem thrust resistance of RTF,RT and RF were significantly higher than that of RM model,and the single stem thrust resistance increased by 13.41%,6.87%and 6.79%respectively,of which RTF was 6.13%and 6.21%more than RT and RF.The RTF model of the highest rice yield was 6.97t·hm^-2,a rice monoculture pattern by15.21%.（2）The ricr-turtle-fish symbiosis system can improve soil physical structure,increase soil nutrient,fertilization effect formation.The surface soil bulk density of RTF,RT and RF model 0⁵cm in mature period were significantly lower than that of RM model,which decreased by 7.52%,5.26%and 2.26%respectively,and there was no significant difference in soil bulk density between 6¹0cm and 11-15cm.The total porosity of 0⁵cm soil layer in RTF,RT and RF mode is significantly higher than that in RM mode,which increased by5.17%,4.83%and 4.23%,respectively.The non capillary porosity,0⁵cm soil RTF,RT and RF patterns were all significantly higher than those of RM mode,and RTF,RT and RF mode had no significant difference（P<0.01）.The contents of available nitrogen in 0⁵cm soil layer of RTF,RT and RF models were higher than those in RM mode,reaching a very significant level（P<0.01）,which increased by 11.47%,6.06%and 9.13%respectively.The content of available phosphorus in the RTF,RT and RF models of each soil layer was higher than that of RM model,reaching a very significant level（P<0.01）.The content of available phosphorus in 0⁵cm soil layer RTF,RT and RF increased by 18.52%,13.52%and 10.95%respectively compared with the RM model.The content of available potassium in 0⁵cm soil,RTF,RT and RF were all higher than that of RM model,which increased by 13.72%,10.04%and 8.51%respectively,and the difference of 11¹5cm did not reach the very significant level（P<0.01）.（3）The ricr-turtle-fish symbiosis system has liquid financial income and the environment and significant economic benefit.The financial revenue of RTF,RT and RF is obviously higher than that of RM model,which is increased by 42704,15952 and25620CNY·hm^-22 respectively,and RTF mode is increased by 27472 and 17084 CNY·hm^-2respectively than RT and RF mode.The environmental and economic benefits of RTF,RT and RF were significantly higher than those of RM model,which increased by 43097,15482and 25903 CNY·hm^-2 respectively,and RTF mode increased by 27615 and 25093CNY·hm^-22 respectively than RT and RF models.