2种稻虾共作模式对土壤有机氮矿化作用的影响

Effects of two rice-shrimp co-cultural models on soil organic nitrogen mineralization

  • 摘要: 【目的】研究2种稻虾共作模式对稻田耕层下部土壤有机氮矿化作用的影响及相关微生物对矿化作用的响应机制,为稻虾共生模式中虾类对土壤氮素肥力的影响机理研究及制定氮肥施用方案提供理论依据。【方法】采用对比试验,测定分析稻—红螯螯虾共作模式(RC)与稻—罗氏沼虾共作模式(RM)耕层下部(10~20 cm)土壤有机氮矿化作用相关参数、土壤氮素含量及微生物群落结构组成,并分析微生物群落与矿化参数的相关性。【结果】与试验初期相比,末期土壤全氮和铵态氮含量均有所下降,初期RC模式与RM模式间全氮含量无显著差异(P>0.05),而末期RC模式全氮含量显著低于RM模式(P<0.05,下同);试验末期RC模式中土壤累积氮矿化量、矿化势、可矿化氮比例分别为131.21±2.12 mg/kg,242.62±5.18 mg/kg,(0.31±0.01)%,分别显著高于RM模式的119.85±1.36 mg/kg,217.51±1.83 mg/kg,(0.28±0.01)%。微生物群落结构分析结果显示,至试验末期,RC模式Shannon指数显著低于RM模式,2种模式间群落结构组成有显著差异,RC模式中放线菌门相对丰度显著高于RM模式,而脱硫杆菌门、粘菌门、硝化菌门相对丰度则显著低于RM模式。相关分析结果表明,累积氮矿化量、矿化势、可矿化氮比例与放线菌门、绿弯菌门、变形菌门均呈极显著正相关(P<0.01,下同);而与拟杆菌门、脱硫杆菌门、粘菌门、硝化螺旋菌门呈极显著负相关。【结论】虾类的生活习性不同影响土壤微生物的群落结构组成,导致2种稻虾共作模式耕层下部10~20 cm土层土壤有机氮的矿化作用产生差异。在江苏省靖江市,与稻—罗氏沼虾共作模式相比,稻—红鳌螯虾共作模式中有机氮的矿化作用更强,矿化势等相关参数更高,具有较高的供氮潜力。

     

    Abstract: 【Objective】To analyze the effects of rice-shrimp co-cultural model on lower arable stratum of paddy soil nitrogen mineralization and microbial response mechanism,so as to provide a theoretical reference for study on mechanism of shrimp on soil nitrogen fertility and formulation of nitrogen fertilizer application scheme.【Method】Comparison experiment was conducted to determine the parameters related to arable stratum(10-20 cm),soil organic nitrogen mineralization,soil nitrogen content and microbial community structure under rice-Cherax quadricarinatus co-cultural model (RC)and rice-Macrobrachium rosenbergii(RM)co-cultural model. Meanwhile,the correlation between microbial community and mineralization parameters was analyzed.【Result】Compared with the beginning period,contents of soil total nitrogen and ammonium nitrogen decreased at final stage,and no significant difference in total nitrogen content between the two models at beginning period(P>0.05)had been found,while the total nitrogen content of RC was significantly lower than RM,at final period(P<0.05,the same below). The results showed that the cumulative mineralization,mineralization potential,and nitrogen mineralization ratio[131.21±2.12 mg/kg,242.62±5.18 mg/kg,(0.31±0.01)%]in RC were significantly higher than those in RM[119.85±1.36 mg/kg,217.51±1.83 mg/kg,(0.28±0.01)%]at the end of the experiment,respectively. Meanwhile,microbial community data showed that Shannon index of RC was significantly lower than that of RM at final period,and there were significant differences in community structure between RC and RM. In addition,the relative abundance of Actinobacteriota in RC was significantly higher than that in the RM,while the relative abundances of Desulfobacterota,Myxococcota,and Nitrospirota were significantly lower than that in the RM. Moreover,the correlation analysis showed that the cumulative nitrogen mineralization,mineralization potential,and the nitrogen mineralization rate were extremely positive corelated with the Actinobacteriota,Chloroflexi,and Proteobacteria(P< 0.01,the same below),but were extremely negative correlated with Bacteroidota,Desulfobacterota,Myxococcota,and Nitrospirota.【Conclusion】Different living habits of shrimp affect the composition of soil microbial community and create differences in arable stratum(10-20 cm)soil microbial community structure. Hence,In Jingjiang,Jiangsu Province,compared with the RM,there is stronger mineralization and higher values of the mineralization potential and other related parameters in RC,which is more beneficial to the growth of rice.

     

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