Study On Fluxes Of Methane Emission And Soil Physics-Chemistry Factors In Rice-goldfish Complex Ecosystem

Utilize the principle of rice -fish's intergrowth,the author carried out the study on goldfish breading in paddy field from March to October in 2004,in chang zhu village in Taojiang county of Hunan province, put certain amount of goldfish in paddy field to forming the rice-goldfish compound ecosystem. Then to test the fluxes of methane emission,the soil physics-chemistry factor and the water chemical factor. According to the statistical annlysis to the data,we know that ,there is a rule of day variation in the flux of methane emission . The discharge peak appear in 14:00-16:00,and it reach minimum in 0:00-4:00.But the flux of methane emission in rice-goldfish compound ecosystem is lower than that in contrast group, and it's difference is extremely remarkable. The peak of flux of methane emission in rice-goldfish complex ecosystem in the rice surviving stage and the fully tillering of rice .His 15.79mg/m2.h;10.074mg/m2.h. Respectively the coefficient correlation between the flux of methane emissiom and Eh celectric potential of paddy field reducing matter, active reducing matter is -0.8586,0.9547,0.82045 respectively, and it's variation reach the level of extremely remarkable.After one season, the weight of 0-20cm paddy field of rice-goldfish compound.ecosystem was decreased by 0.11g/cm3 ,the hole degree in soil was increased by 8.03%, and it's effect reaches the extremely remarkable. But the influence of non-capillary porosity is not obvious, the quick-acting nitrogen, qicck-acting phorphorus, quick-acting potassium,organic content have been improved by separately 11.96mg/kg,0.87mg/kg,4.49mg/kg,0.78mg/kg. This indicates that breeding goldfish in paddy field can improve the level of nutrition of soil notably,but the difference of pH is not obvious between that in the paddy-goldfish compound ecosystem and that in contract group .breeding goldfish in paddy field can improve the level of dissowed oxygen notably. The rale of day's variation has positive relation with the water temperature.It hit the maximum in 14:00-16:00 and it reach the minimum at 5:00. The density of NH4+ in water has positive correlation with the water temperature and the difference is not obvious relation to the time .The density of NH4+ in the water of rice-goldfish compound ecosystem is higher than that of the contrast group. The day's rale of S2- in the water of rice-goldfish compound ecosystem and the water of paddy field is thatboth reach the minimum at 18:00 and hit maximum in 4:00-5:00,but the density of S2-in the water of rice-goldfish compound ecosystem is little lower than that in the paddy field, and it's correlation to water few is not obvious. While the pH has positive correlation with water temperature, both in the rice-goldfish compound and paddy field. It hit maximum at 2:00pm and reach minimum at 6:00, and the pH of water in rice-goldfish compound ecosystem is lower than that of in paddy field.Rice fish intergrowth has certain benefit to the production of rice.The increasing production is 249kg. hm-2 more than the production of contrast group. The increasing production rate is 4. 98%, and the economic benefits is 1684 yuan more than the contrast group. Otherwise, the weeds in rice-fish compound ecosystem is out-of-eyes. In addition, the reap of goldfish in every district is 172(the total length is 13-15cm averagly),the rate of survival is 86%.