Difference in pH value and nutrient and bacterial diversity in the carya cathayensis forest soil under different management models

Abstract

To optimize management of the Carya cathayensis forest through the diversity and function of soil bacteria, disease index, soil pH, and nutrient and soil bacterial diversity were investigated under ecological management and excessive management during the Botryosphaeria dothidea infected period using 16S rRNA gene high-throughput sequencing technology. The correlations between each interrelationship factors were also analyzed. Results showed that the disease index of the ecologically managed forest was 3.3±3.35, which was significantly lower than that of the excessively managed forest with 81.9±1.27. Moreover, ecological management significantly improved the ability of hickory forest resistant to B. dothidea. The soil pH value of the ecologically managed forest was near neutral with a reading of 6.64±0.06, which was significantly higher than that of excessively managed forest soil with 5.80±0.04. The contents of available phosphorus, available potassium, and available nitrogen in the excessively managed forest soil were 18.10±0.58 mg/kg, 698.63±11.24 mg/kg and 227.13±3.81 mg/kg, which were significantly higher than those in the ecologically managed forest respectively, with 14.94±0.27 mg/kg, 497.13±6.19 mg/kg and 195.28±6.01 mg/kg. There were 14 and 21 major bacterial genera found in the ecologically and excessively managed forest soil samples, respectively. In ecologically managed forest soils, the dominant genera were Sphingomonas, Gaiella and Ly-sobacter, and the relative abundance of these was significantly higher than excessively managed forest soils. Bryobacter, Candidatus Solibacter, and Bradyrhizobium were the dominant genera in the excessively man-aged forest soils, and their relative abundance was significantly higher than the ecologically managed forest soils. There was no significant difference of OTUs or Ace, Chao, Shannon and Simpson indices between ecologically and excessively managed forest soils. Redundancy analysis (RDA) and Monte Carlo testing showed that pH value, available phosphorous and available nitrogen had significant effects on the bacterial flora of the dominant bacterial species in the soil (P < 0.05). Our results can provide valuable references for the sustainable management of hickory forests.