Survey of Soil Properties of Representative Vine, Olive, and Citrus Cultivations in Peloponnese, Southern Greece

Citrus, olives, and vines are among the crops that dominate agriculture in southern Greece. A soil sampling campaign was carried out in 30 different representative sites of Peloponnese, Greece, almost exclusively dominated by vineyards and olive and citrus orchards. Soil samples were analyzed for pH; calcium carbonate (CaCO3); organic matter; total nitrogen (N); ammonium (NH4); nitrate (NO3); available phosphorus (P); exchangeable potassium (K), magnesium (Mg), and calcium (Ca); and diethylenetriaminepentaacetic acid (DTPA) manganese (Mn). The results suggest that soil organic carbon (C) and total N in the soil, followed by available P, K, and Mn, are the major soil fertility constraints to crop production in the area. Most of the studied soils (77%, 84%, and 61% for vine, olive, and citrus, respectively) were within the favorable pH range for the crops, and 22%, 14%, and 29% of soils in vine, olive, and citrus fields respectively had high CaCO3 values (>20%). Also, 91%, 75%, and 76% of soils in vine, olive, and citrus fields respectively had organic C content below the threshold value of 20 g kg(-1). Similar trends were found for total N. Concentration of NH4 in soils was found to be high for the 67% of data, and 46%, 55%, and 29% of soils in vine, olive, and citrus fields respectively had available P below the threshold value of 12 mg kg(-1). Low Mg content was found for 24%, 55%, and 7% of soils in vine, olives, and citrus fields respectively. Potassium levels less than the critical value of 0.26 cmol kg(-1) were found for 20%, 50%, and 33% of vine, olive, and citrus fields respectively. On the other hand, across all the studied sites, 67% of the soils contained high exchangeable Ca (>20 cmol kg(-1)) and 58% of Mn data varied in low levels (<5 mg kg(-1)).