稻虾共作模式的“双刃性”及可持续发展策略

“Dual character” of rice-crayfish culture and strategies for its sustainable development

近年来,稻虾[水稻-克氏原螯虾(小龙虾)]共作模式由于其较高的综合效益而在全国范围内得以大力发展。其中以湖北省稻虾共作发展最为迅速,面积大,技术也较为成熟,并形成了"潜江模式"。本文介绍了稻虾共作模式的特点及其发展情况,以湖北省稻虾共作模式为研究对象,采用产业调查,结合试验示范和定位试验,研究了稻虾共作模式的生产和生态效应,重点分析了稻虾共作模式的"双刃性"。稻虾共作模式的"双刃性"主要体现在(1)稳粮增效,但同时存在重虾轻稻的现象:稻虾共作模式较传统水稻单作模式可增产4.63%~14.01%,改善稻米品质,但部分稻虾共作模式中忽略水稻的管理,导致水稻产量偏低;(2)提高土壤肥力,但同时加剧了土壤次生潜育化:稻虾共作模式土壤中易氧化态有机碳(ROC)、全氮、全磷、全钾含量要高于传统水稻单作模式,但稻虾共作模式土壤颜色偏暗,土壤结构更为紧密,潜育化明显;(3)涵养水源,但同时可能增加水资源消耗:稻虾共作模式中地下水位高的稻田水分利用率提高,储水功能增强,但地下水位低的稻田可能增加50%~80%的耗水量;(4)减肥减药、提高水体养分含量,但同时增加了水体富营养化的风险:稻虾共作模式肥料和农药成本分别降低了79.5%和50.0%,稻虾共作模式田面水的全氮、全磷含量及硝态氮、氨态氮含量均高于水稻单作;(5)虫害减轻,但某些病害加重,同时生物多样性发生变化:稻虾共作模式螟虫发生减轻,但基腐病加重,生物多样性随共作年限先降低后又增高。根据以上现状与问题,本研究提出了稻虾共作的模式优化及建议,如因地制宜,避免盲目发展;研究标准,规范化发展;优化模式,科学水肥调控;因势利导,防治病虫草害,为稻虾共作模式的可持续发展提供依据。

Rice-crayfish culture has been greatly developed in China in recent years due to its high comprehensive benefits.Especially,rice-crayfish culture has been rapidly developed in Hubei Province,where has a large area and proven technique of rice-crayfish culture,and developed the“Qianjiang Mode”.In this paper,we introduced the characteristics and the development of rice-crayfish culture,and studied the production and ecological effects of rice-crayfish culture in Hubei Province by investigation,demonstration and long-term experiment.And the“dual character”of rice-crayfish culture was illuminated.The“dual character”of rice-crayfish culture was mainly reflected by the following phenomena.(1)Rice-crayfish culture stabilized food synergy,but favored crayfish over rice.Rice yield of rice-crayfish culture was increased by4.63%?14.01%compared with conventional rice culture,and the rice quality was improved.But sometimes the rice yield was decreased due to the poor management for rice.(2)Rice-crayfish culture improved the soil fertility,but aggravated the soil gleization.The contents of readily oxidizable organic carbon(ROC),total N,total P and total K in soil of rice-crayfish field were higher than those of conventional rice field,but soil color was darker,structure was tighter,the gleization was obvious.(3)The rice-crayfish culture conserved water,but in some cases increased water consumption.The water use efficiency and water conserving capacity in field with high groundwater level were higher,but water consumption was increased by50%?80%in field with low groundwater level.(4)The rice-crayfish culture decreased fertilizers and pesticides application,increased water nutrient concentration,but also increased the risk of water eutrophication.The costs of fertilizers and pesticides were decreased by79.5%and50.0%,respectively.The total N,total P,nitrate-N and ammonia-N concentrations were higher in the surface water of rice-crayfish field.(5)The pests amounts were deceased,but some disease occurrence increased and biodiversity changed in rice-crayfish field.The lepidoptera pests were decreased,but the basal rot was heavier,and the biodiversity was decreased firstly,then increased by years in rice-crayfish culture.Finally,we made some suggestions for improving the rice-crayfish culture,such as adjusting managements to local conditions and decreasing blindness,standardizing development,optimizing pattern and regulating water and fertilizer utilization,and scientific control of disease,pests and weed.These suggestions may ensure the sustainable development of rice-crayfish culture.