贵州省烟草青枯病害区根际土壤养分及酶活性特征分析

Characteristics of soil nutrients and enzyme activities in rhizosphere of tobacco affected by bacterial wilt in Guizhou Province,China

本文采用多点随机区组设计,以黔东南低山丘陵区(中亚热带季风性暖湿气候)、黔中丘陵盆地区(北亚热带季风湿润气候)和黔西北高原山地区(亚热带季风性湿润气候)三大气候区为研究区域,研究了贵州省不同气候下健康烟株和患青枯病烟株根际土壤养分及酶活性的差异,以及气候对此差异的影响,为从土壤肥力和酶活性方向探索青枯病害发生规律并进行病害预防提供理论依据。结果表明:与健康烟株相比,患病烟株根际土壤的pH值、有效磷和脲酶活性分别显著降低了4.66%、25.98%和21.92%;而有机质、阳离子交换量(CEC)、全氮、碱解氮、全磷、全钾和速效钾含量及过氧化氢酶活性均显著提高,且升高趋势在高海拔的亚热带季风性湿润气候下更为明显;Pearson相关性分析表明,健康处理的受测指标间呈显著相关性的指标更多且相关性更强;因子分析表明,根际土壤pH值、脲酶和磷酸酶活性偏低及CEC、全氮、全磷和速效钾含量及过氧化氢酶活性偏高有可能使烟草更易患青枯病;通过逐步判别分析可知,由土壤pH值、CEC、全氮、碱解氮和速效钾所构建的判别模型判别准确率达100%,可对未知植烟土壤上烟株是否易患青枯病进行预测预报。可见,烟草根际土壤CEC、全氮、碱解氮、速效钾偏高和土壤pH偏低可能更易使烟草患青枯病害,调控根际营养平衡对提高土壤抑病能力和构建抑病型土壤具有重要作用。

To explore the occurrence regularity of tobacco bacterial wilt and provide theoretical basis for disease prevention in the respect of soil fertility and enzyme activity, the difference of rhizosphere nutrients and enzyme activities between healthy tobacco and diseased tobacco which suffered from bacterial wilt in Guizhou Province and the effects of climate on this difference were studied with multi-site randomized complete block design in three climate zones named mountain-hill areas of southeastern Guizhou(mid-subtropical monsoon humid climate), the hilly basin of central Guizhou(northern subtropical monsoon humid climate) and the plateau mountainous area of northwestern Guizhou(subtropical monsoon humid climate). The results showed that compared with the healthy, rhizosphere soil pH, available phosphorus and urease activity of the diseased were significantly reduced by 4.66%, 25.98% and 21.92%, respectively;while organic matter, CEC, total nitrogen, alkali hydrolyzable nitrogen, total phosphorus, total potassium, available potassium and catalase activities were significantly higher, respectively, and the rising trend was more obvious in the humid subtropical monsoon climate at high altitude. Pearson correlation analysis revealed that the correlation between tested indexes of the healthy was more and stronger than the diseased. Factor analysis made the conclusion more clear that the lower the pH, urease and phosphatase activity and the higher CEC, total nitrogen, total phosphorus available potassium and catalase activities, tobacco might be more susceptible to bacterial wilt. The stepwise discriminant analysis indicated that the discrimination model whose discriminant accuracy was 100% was constructed by soil pH, CEC, total nitrogen, alkaline hydrolysis nitrogen and available potassium, which could predict the susceptibility of tobacco plants to bacterial wilt in unknown soil. In conclusion, tobacco rhizosphere soil CEC, total nitrogen, alkaline hydrolyzable nitrogen and available potassium were higher and soil pH was lower, which might be more susceptible to tobacco wilt disease. Regulation of rhizosphere nutrients balance will play an important role in improving soil suppressive ability to bacterial wilt and constructing disease-resistant soil.