玉米/花生间作条件下土壤环境因子的相关性和主成分分析

Correlation and Principal Component Analysis of the Soil Environmental Factors in Corn/Peanut Intercropping System

玉米/花生间作具有明显的间作优势,对作物生长和产量均有促进作用。为了阐明玉米/花生间作效应机制,测定了玉米/花生间作根际土壤养分含量、酶活性和微生物数量的变化规律,并对这些环境因子进行相关性和主成分分析。结果表明,与单作玉米和单作花生相比,玉米/花生间作显著提高了根际土壤的全氮、有效氮、有效磷含量以及脲酶和酸性磷酸酶活性,促进了间作玉米根际土壤细菌和微生物总数量显著增加。相关分析表明,有效磷含量与脲酶和酸性磷酸酶活性呈极显著正相关(P<0.01),脲酶活性和酸性磷酸酶活性显著正相关(P<0.05),真菌和放线菌数量显著正相关(P<0.05)。总钾含量和p H值、蔗糖酶活性呈显著负相关(P<0.05),蛋白酶和过氧化氢酶呈极显著负相关(P<0.01)。主成分分析获得3个主成分,解析贡献率分别为48.981%,43.617%和7.402%。第一主成分主要是放线菌、真菌、有效磷等组成,第二主成分主要为有机质和p H,第三主成分主要是总氮和细菌。经标准化后计算栽培措施得分显示:间作花生得分最高1.937,其次是间作玉米1.008,两者均显著高于单作玉米和单作花生。该研究表明玉米/花生间作系统的生态环境优于单作系统,机制解析为玉米/花生间作可明显促进土壤有效氮磷含量、脲酶和酸性磷酸酶活性及微生物数量的增加,进而改善土壤微生态环境。

Corn/peanut intercropping is a popular cultivation method in southern China and has the advantages of apparently improved plant growth and increased yield compared with monoculture. In order to elucidate the mechanism of corn/peanut intercropping, changes in nutrients, enzymes and microorganisms in the plough layer soil after corn/peanut intercropping were determined. The correlation and principal component analysis were also done. The results showed that the total nitrogen, available nitrogen, available phosphorus, urease activity and acid phosphatase activity of rhizosphere soil were significantly increased by intercropping corn and intercropping peanut compared with mono-cropping corn and mono-cropping peanut systems. Correlation analysis showed a significant positive correlation between the activity of available phosphorus, urease and acid phosphatase(P<0.05), and the content of fungi and actinomyces(P<0.05). A significant negative correlation between total pH, invertase and potassium(P<0.05), protease and catalase were noticed(P<0.01). The analytical contribution rates of the three principal components were 48.981%, 43.617% and 7.402%, respectively. The first principal components were actinomycetes, fungi and available phosphorus, the second principal components were mainly organic matter and pH, and the third principal components were total nitrogen and bacteria. After standardized calculation, the highest score was 1.937 for intercropping peanut and 1.008 for intercropping corn, both of which were significantly higher than the mono-cropping control, respectively. This indicates that the intercropping system is better option than the mono-cropping system due to higher soil nutrient, microorganism, urease and acid phosphatase activities. Therefore, corn/peanut intercropping can improve rhizosphere soil microecological environment. This study lays a solid theoretical foundation and provides technical guidance for the analysis of intercropping mechanism of corn and peanut.