两种基于芦苇秸秆还田的改良措施对崇明东滩围垦土壤理化性质和微生物呼吸的影响

Effect of Two Improving Measures Based on Returning Phragmites communis Straw on Soil Phy-chemical Properties and Microbial Respiration of the Reclaimed Lands in Chongming Dongtan,China

在崇明东滩湿地公园设置了3块实验田,研究基于芦苇直接还田(处理Ⅰ)和堆肥后还田(处理Ⅱ)的处理措施对盐碱土壤的改良效应以及对土壤微生物呼吸和植物生长的影响,并通过主成分分析法评价仅考虑传统土壤肥力指标及加和了土壤微生物呼吸和植物生物量等碳收支指标的土壤综合改良效应。结果表明,两种模式都能显著提高土壤的养分。总氮、总磷和总钾均显著高于对照(P<0.05),有机质较对照分别提高10.8%(P=0.053)和10.9%(P=0.052);地上生物量为对照的344%(P=0.000)和167%(P=0.000),但土壤微生物呼吸仅分别较对照提高14%(P=0.085)和43%(P=0.001)。主成分分析结果显示仅考虑传统的土壤肥力指标,对照、处理Ⅰ、处理Ⅱ的综合得分分别为-0.641、0.260、0.381,加和土壤微生物呼吸与植物生物量后综合主成分得分为-1.011、0.644、0.367。这表明按传统评价指标,处理Ⅱ是较好的改良模式,但加和了土壤微生物呼吸与植物固碳量等碳收支指标后,处理Ⅰ得分高于处理Ⅱ,因此这是一种相对低碳化的改良模式。

Returning crop straw to land is generally an important measure to soil improvement.Phragmites communis is the most plentiful straw resource in Chongming Island,China.However,few studies on returning Phragmites communis straw and its soil improving effect have been reported.In the experiment,three experimental fields in Chongming Dongtan were selected to study the effect of two improving measures based on returning Phragmites communis straw（measure I：returning Phragmites communis straw plus tillage and fertilization;measure Ⅱ：returning Phragmites communis straw after composting plus tillage and fertilization） on phy-chemical properties and microbial respiration of saline-alkali soil.In addition,the principal components analysis（PCA） was used to evaluate the comprehensive soil improving effect of the two improving measures.The results showed that both measure I and measure Ⅱ could significantly increase soil nutrient,e.g.TN、TP、TK by 48%、48%、19% and 24%、74%、105%,and soil organic carbon by 10.8% and 10.9%,in comparison with the control.Plant biomass was as 3.44 times and 1.67 times high as that in the control,but soil microbial respiration increased by only 14% and 43%.The PCA results indicated that synthetic scores of the control,measure Ⅰ and measure Ⅱ were-0.641,0.260 and 0.381 respectively when just considering the traditional soil fertility index.However,after adding soil carbon turnover index,such as soil microbial respiration and plant biomass,the synthetic scores were-1.011、0.644 and 0.367,respectively.Therefore,measure Ⅱ was the optimal mode in the view of the traditional standard,but when taking soil microbial respiration and plant biomass into accounts,the score of measureⅠ was higher than measure Ⅱ.Thus,measure Ⅰ was relatively a low carbon improving mode.