Phenolic Constituents from the Fruits of Areca catechu and Their Anti-bacterial Activities Influence of different planting spacing of areca nut intercropping with Vanilla on soil microbes and nutrients Effect of different fertilization and irrigation practices on soil ammonia volatilization of Arecanut (Areca catechu L.) Research on the ratio and contents of N, P, K by arecanut (Areca catechu L.) leaves in different growth conditions