不同轮作模式下旱地番茄土壤理化性质及细菌群落组成特征

Soil physical and chemical properties and bacterial community composition in dryland tomato under different rotation patterns

为研究不同轮作模式对旱地番茄土壤肥力及细菌群落组成特征的影响,以旱地番茄-豆角-糯玉米-旱地番茄(LVZm)、旱地番茄-豆角-西葫芦-旱地番茄(LVCp)、旱地番茄-豆角-花生-旱地番茄(LVAh)、旱地番茄-豆角-葱-旱地番茄(LVAf)、旱地番茄-豆角-秋葵-旱地番茄(LVAe)、旱地番茄-豆角-黄瓜-旱地番茄(LVCs)、旱地番茄连作(CK)为研究对象,测定土壤容重、土壤团聚体结构、土壤养分、土壤酶活性、细菌丰富度和多样性,并通过主成分分析选出最优轮作模式。结果表明不同轮作处理对土壤容重、土壤团聚体结构和土壤养分的影响存在差异。与对照相比,LVZm、LVAh、LVAf和LVCs处理显著降低了土壤容重;除LVAe处理外,各轮作处理均显著降低0~10 cm土层的<0.25 mm土壤团聚体含量;除了LVAf处理和LVAe处理有机质含量与对照差异不显著,其余轮作处理有机质含量都显著增加;全氮、全钾差异不显著;除了LVCs处理全磷和碱解氮显著低于对照,其余各轮作处理均显著高于对照;除LVAe处理外,各轮作处理有效磷和速效钾含量均显著高于对照;与对照相比,各轮作处理pH和电导率降低或显著降低,碱性磷酸酶、脲酶、蔗糖酶和纤维素酶活性均增加或显著增加,过氧化氢酶、脲酶和蛋白酶变化不明显。细菌群落组成测定结果表明变形菌门、放线菌门、酸杆菌门、绿弯菌门、芽单胞菌门为各处理的优势菌门,除绝大多数的未知菌属外,溶杆菌属、Subgroup_6、假平胞菌属、藤黄单孢菌属为优势菌属。聚类分析结果表明,LVZm处理和LVAf处理细菌群落结构最相似,LVCp处理与各处理细菌群落结构相差最大。主成分分析(PCA)结果表明,LVAh处理优于其他处理。综上所述,轮作改善了土壤肥力,改变了土壤细菌群落结构,其中以旱地番茄-豆角-花生-旱地番茄轮作模式效果最好。

In order to study the effects of different rotation patterns on soil fertility and bacterial community composition of dryland tomato, dryland tomato-Phaseolus vulgaris-waxy corn-dryland tomato(LVZm), dryland tomato-Phaseolus vulgaris-zucchini-dryland tomato(LVCp), dryland tomato-Phaseolus vulgaris-peanut-dryland tomato(LVAh), dryland tomato-Phaseolus vulgaris-Allium fistulosum-dryland tomato(LVAf),dryland tomato-Phaseolus vulgaris-okra-dryland tomato(LVAe), dryland tomato-Phaseolus vulgaris-cucumber-dryland tomato(LVCs), and continuous cropping of dryland tomato(CK) were used as research objects. The soil bulk density, soil aggregates, soil nutrient content, soil enzyme activity, bacterial richness and diversity were determined, and the optimal rotation mode was studied by principal component analysis. The results showed that the effects of different crop rotation treatments on soil bulk density, soil aggregates and soil nutrients were different. Compared with the control, the LVZm, LVAh, LVAf and LVCs reduced soil bulk density significantly. Except LVAe treatment, every crop rotation treatment significantly reduced the content of aggregates less than 0.25 mm in 0-10 cm soil layer. Compared with the control, the organic matter contents of all crop rotation treatments increased significantly except LVAf and LVAe treatments. There was no significant difference in total nitrogen and total potassium. Compared with the control, total phosphorus and alkali-hydrolyzed nitrogen of all crop rotation treatments increased significantly except LVCs treatments. Compared with the control, the contents of usable phosphorus and available potassium in all crop rotation treatments increased significantly except LVAe treatments. The pH and electrical conductivity of each rotation treatments decreased or significantly decreased, compared with the control, decreased the alkaline phosphatase, urease invertase and cellulase significantly increased, and the variation of catalase, urease and protease was not obvious. The results of the bacterial community composition showed that Proteobacteria, Actinobacteria, Acidobacteria, Chloroflexi and Gemmatimonadetes were the dominant phyla. Lysobacter, Subgroup_ 6, Sphingomonas and Luteimonas were the dominant genera. The results of cluster analysis indicated that the bacterial community structures of LVZm and LVAf were the most similar, and the difference of bacterial community structures between LVCp treatment and the other treatments was the largest. By principal component analysis, the LVAh treatment was better than other treatments. In summary, crop rotation can improve the soil fertility and change the soil bacterial community structure, and LVAh its the best rotation mode.