Abstract:To investigate the effects of different drip irrigation belt layout modes on the distribution of soil phenolic acids, enzyme activities, and microorganisms in the fruit characteristics-crop intercropping system, and to preliminarily explore the relationship between soil phenolic acids and soil biological factors under intercropping drip irrigation conditions, a typical apple (Malus pumila L.)-soybean (Glycine max L.) intercropping system in the loess region of western Shanxi was used was the research object, with three types of drip irrigation belt spacing (L1, L2, L3). The spatial distribution changes of soil phenolic substances, enzyme activity, and microbial quantity under different water distributions were analyzed, and based on this, stepwise regression model was used to analyze the interrelationships among these three soil factors. The results showed that except for benzoic acid and phloroglucinol, the distance between drip irrigation belts had a significant impact on the distribution of phenolic acids (p<0.05), and had a significant impact on the enzyme activity and the distribution of microbial population except for catalase (p<0.05). In the vertical direction, different drip irrigation belt layout modes resulted in more distribution of phenolic acids in deep soil, the number of microorganisms and some enzyme activities first decreased and then increased with the deepening of soil layer in L1 and L2 treatments; In the horizontal direction, the effects of different drip irrigation belt layout modes on the distribution of soil phenolic acids, bacteria, and fungi were consistent with the intercropping control treatment, increasing with the increase of distance from the tree. Under the condition of drip irrigation, phenolic acids except p-hydroxybenzoic acid were significantly inhibited by urease, catalase and actinomycetes, and the total amount of phenolic acids in intercropping soil was less than that in monocropping. L1 treatment had the highest soil enzyme activity and total microbial biomass, while L2 treatment had the lowest accumulation of phenolic acids in the soil. Among them, L2 treatment had a relatively high level of soil enzyme activity on the basis of the lowest accumulation of phenolic acids. Therefore, it is recommended to adopt the pattern of arrange a drip irrigation belt at intervals of one row of soybean in the fruit-crop intercropping system, improving the soil micro-ecological environment can alleviate the inhibition of allelochemicals at the same time.