Assessment of soil fertility variation in an olive orchard and its influence on olive tree nutrition.

Soil fertility variation at olive orchard scale was studied in a rainfed olive orchard located on a topographical sequence in the centre of Tunisia (34.37 N 10.16 E). Soil parameters such as pH, organic matter, gypsum, lime, N, P and K contents and soil electrical conductivity were determined in samples obtained at 1m depth and used to characterize soil fertility. Leaf samples from olive trees (cv Chemlali) 80 yrs old and at squared spacing distance (24x24 m apart) were collected in mid-July 2005 to verify plant nutritional status. A regular 200m x 200m sampling grid was established and the intersection points were georeferenced. Each soil fertility component was analyzed statistically and …