青田稻-鱼共生系统水稻密度对水稻生长及产量构成的影响

青田稻-鱼共生系统是首批入选联合国全球重要农业文化遗产系统(global important agriculture heritage system, GIAHS)保护的试点项目,该系统中最适水稻密度的选择关系到其更好地应用推广。对青田稻-鱼共生系统的水稻栽培密度开展了优化研究,分析3种水稻栽培密度(高、中、低密度株行距分别为20 cm×30 cm、30 cm×30 cm和40 cm×30 cm)下水稻的生长和产量构成,记录3种水稻密度青田田鱼(Cyprinus carpio var.color)的存活和生长情况。结果表明:低密度(40 cm×30 cm)条件下的水稻分蘖数和生物量在拔节期后均显著高于高密度;在3种密度中,低密度(40 cm×30 cm)下的水稻茎秆构成性状优势明显;栽培密度对水稻产量影响不显著。灰色关联度分析表明,与水稻产量关联度最大的茎秆构成因子是穗长、关联度最大的产量构成因子是千粒重。水稻中密度(30 cm×30 cm)栽培时青田田鱼的特定生长率(specific growth rate, SGR)达到最高值4.54%±0.03%,极显著高于高密度(20 cm×30 cm)时的3.62%±0.04%。各水稻密度下的青田田鱼的存活率(survival rate, SR)无显著差异。基于水稻生长和综合效益考虑,青田稻-鱼共生系统采用中密度(30 cm×30 cm)栽培方式可以在保证水稻不减产的同时获得更快的田鱼生长速率。

Effects of rice density of Qingtian rice-fish coculture system on rice growth and yield composition

Qingtian rice-fish coculture system is one of the first pilot sites of Global Important Agriculture Heritage System (GIAHS) designated by FAO in 2005. The optimization of rice-fish coculture mode such as the selection of optimal rice density in the coculture system will be much helpful to the local promotion of this rice fish coculture model. In this study, 3 rice planting density (by different line and plant spacing) were chosen in order to compare the effects of the rice spacing on the rice growth and yield, the survival rate (SR) and specific growth rate (SGR) of the fish (Cyprinus carpio var. color). The 3 rice cultivation densities (high, medium and low density) were plant spacings of 20 cm×30 cm, 30 cm×30 cm and 40 cm×30 cm, respectively. The results showed that:the tiller number and biomass of rice at low density (40 cm×30 cm) were significantly higher than those of the high density groups after elongation stage; there were obvious advantages of the rice stem characters at low density (40 cm×30 cm) among the 3 densities; and the cultivation density had no significant effect on rice yield. The grey correlation analysis showed that the greatest correlation with rice yield was the panicle length among the rice stem characters, and the greatest correlation with rice yield was the 1000-grain weight among rice yield compositions. The SGR of fish reached the highest value 4.54%±0.03% at the medium density (30 cm×30 cm), which was extremely significantly higher than that at the high density (20 cm×30 cm) 3.62%±0.04%. The survival rate of fish was not significantly different among treatments. Based on rice growth and production efficiency, the medium-density (30 cm×30 cm) of Qingtian rice-fish coculture system can be the priority to be used to get faster growth rates of fish while ensuring rice yield.