Abstract: This study investigated the sod-culture of olive orchards either intercropped with vetch (Vicia sepium) or with natural grass mulch applied. Measurements were taken of the soils’ physical and chemical properties, enzyme activities and the number of microorganisms. The number of new olive shoots, rate of flower bud differentiation, per inflorescence flower number and a number of other indexes were also measured. The results showed that the sod-culture produced by both vetch intercropping and natural grass mulching improved the soil water content, alkali-hydrolysable nitrogen content, available phosphorus content, soil urease activities, phosphatase and invertase activities. As a whole, the enhancement effect of intercropping with vetch was higher than that of natural grass mulching. Both intercropping with vetch and natural grass mulching improved the content of soil organic matter and reduced soil pH values. Intercropping with vetch reduced catalase activity, while natural grass mulch increased catalase activity. The sod-culture produced by both intercropping with vetch and natural grass mulching increased the number of the soil bacteria, actinomyces and fungi, inhibited new shoot elongation and improved the development of short and middle length bearing branches. This is very beneficial for improving the structure of fruit-bearing branches. Intercropping with vetch also improved the flower bud differentiation rate and the number of flower buds per length of the single branch, and especially the bud differentiation rate in short shoot branches. In conclusion, the sod-cultures produced in olive orchards by both intercropping with vetch and natural grass mulching checked the over-luxuriant growth of new shoots and promoted flower bud differentiation by improving soil properties and fertility levels.

Key words: sod-culture, soil property, floral physiology, olive