Effects of different soil management methods on olive yield and quality in organic olive groves

Cover crops and organic mulch applications increase olive yield in a sustainable way, can contribute on the quality of olive and olive oil and perform a limiting effect on possible negative effects on the environment. By taking into consideration these effects, a field experiment was designed in organic olive grove at Atatürk Horticultural Central Research Institute in which 4 different ground management methods were implemented. The methods tested were organic mulch (straw), cover crops (vetch + oats), natural vegetation (no-till) and traditional tillage. The effects of these methods were evaluated in respect to olive yield and fruit quality. The trial aimed to find a sustainable olive grove management system that could be recommended to the producers. Tested ground management methods did not show any statistically significant effects on yields or on olive fruit quality. Even though some positive effects of cover crops on the soil properties have started to appear as confirmed by the significant differences obtained at the final sampling date, the effects of tested soil management methods' on soil properties did not differentiate clearly for most parameters. Economic analyses have shown that as the 3-year average, the highest income is obtained from cover crop plots. Although plots with mulch application revealed a good income, because of the high current cost of hay, it was not economically sound. Based on these results, it is possible to propose using cover crops – under conditions where there is no strong competition – instead of traditional tillage which has additional costs and possible negative effects on environment. It is expected that maintaining the same research plan for longer terms will further differentiate the effects of soil management methods and over the years, and significant impacts of applications will also be seen on yield and quality of the olives.