Intercropping and nitrogen enhance eucalyptus productivity through the positive interaction between soil fertility factors and bacterial communities along with the maintenance of soil enzyme activities

Abstract

AbstractThe nitrogen (N) demand of eucalyptus plantations is considered to be effectively supplemented by the addition of N‐fixing plants. However, the effects of intercropping combined with N fertilization on the enzyme activity, soil fertility, and bacterial relationships, such as bacterial‐mediated nutrient cycling, remain elusive. A pot experiment was performed to assess the effect of intercropping and fertilization on eucalyptus productivity, soil fertility, enzyme activity, and bacterial characteristics, in addition to any probable linkages between these factors and how the interactions promote eco‐friendly production in eucalyptus plantations. Intercropping eucalyptus combined with suitable N fertilization (3 g plant−1) resulted in a higher Chao1 and Shannon diversity of bacterial communities; increased soil fertility, pH, enzyme activity, and eucalyptus productivity; as well as generated a stronger positive interaction between dominant bacterial taxa and soil environmental variables. According to the network and structural equation model (SEM) analysis, the interaction between dominant bacterial taxa and soil environmental variables was clearly linked to N application, and deficient or excess N fertilizer may exert a detrimental effect on eucalyptus productivity. This suggests that reasonable N application in intercropping is a potentially sustainable solution for maintaining eucalyptus productivity and soil quality under N‐limited conditions.