稻虾共作模式对涝渍稻田土壤理化性状的影响

Effect of integrated rice-crayfish farming system on soil physico-chemical properties in waterlogged paddy soils

  • 摘要: 稻虾共作模式是一种以涝渍水田为基础,以种稻为中心,稻草还田养虾为特点的复合生态系统。本文通过10年(2005-2015年)定位试验,以中稻单作模式为对照,研究了稻虾共作模式对0~10 cm、10~20 cm、20~30 cm和30~40 cm土层土壤理化性状以及水稻产量的影响;采用投入产出法,评估了稻虾共作模式的经济效益。结果表明,长期稻虾共作模式显著降低了15~30 cm土层的土壤紧实度,其在15 cm、20 cm、25 cm和30 cm处的土壤紧实度较中稻单作模式分别降低了20.9%、29.9%、24.8%和14.7%。长期稻虾共作模式提高了0~40 cm土层中>0.25 mm水稳性团聚体数量、平均质量直径和几何平均直径,但降低了0~20 cm土层的团聚体分形维数。相对于中稻单作模式,长期稻虾共作模式显著提高了0~40 cm土层有机碳、全钾和碱解氮含量,0~30 cm土层全氮含量,0~10 cm土层全磷和速效磷含量以及20~40 cm土层速效钾含量。稻虾共作模式显著降低了0~10 cm土层还原性物质总量,但提高了20~30 cm土层土壤还原性物质总量。稻虾共作模式的水稻产量较中稻单作模式显著提高,增幅为9.5%,其总产值、利润和产投比较中稻单作模式分别增加了46 818.0元·hm-2、40 188.0元·hm-2和100.0%。可见稻虾共作模式改善了土壤结构,增加了土壤养分,提高了水稻产量以及经济效益,但增加了10 cm以下土层潜育化的风险。

     

    Abstract: Integrated rice-crayfish system is a complex ecological system based on waterlogged paddy field cultivation characterized with crayfish fed by rice straw. Using rice monoculture system as the control, a 10-year (2005-2015) field experiment was conducted to study the effects of integrated rice-crayfish system on rice yield and soil physico-chemical properties at soil depths of 0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm. The economic benefit of integrated rice-crayfish system was evaluated using the input-output method. The results indicated that long-term integrated rice-crayfish system significantly reduced soil compaction at the 15-30 cm layer. The soil compaction in 15 cm, 20 cm, 25 cm and 30 cm soil was lower in integrated rice-crayfish system than in rice monoculture system by 20.9%, 29.9%, 24.8% and 14.7%, respectively. Long-term integrated rice-crayfish system increased soil water-stable aggregates (>0.25 mm) content, aggregate mean weight diameter (MWD) and geometric mean diameter (GMD) in the 0-40 cm layer, but decreased aggregate fractal dimension (D) in the 0-20 cm layer. Compared with rice monoculture system, long-term integrated rice-crayfish system significantly increased the contents of soil organic carbon, total K and available N in the 0-40 cm layer, then total N in the 0-30 cm layer, total P and available P in the 0-10 cm layer and available K in the 20-40 cm layer. The total amount of reducing matter in the 0-10 cm soil layer of the long-term integrated rice-crayfish system was lower than that in the monoculture rice system, but it was higher in the 20-30 cm soil layer. Rice yield in integrated rice-crayfish system significantly increased by 9.5% than that in the monoculture rice system. The output, profit and ratio of output to input in integrated rice-crayfish system were higher than those in the monoculture rice system by 46 818.0 ¥·hm-2, 40 188.0 ¥·hm-2 and 100.0%, respectively. It was therefore clear that integrated rice-crayfish system improved soil structure, enhanced soil nutrient and increased rice yield and economic benefit. However, it also increased the risk of soil gleying in the 10 cm depth.

     

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