PHYSICAL AND PHYSICO-CHEMICAL PROPERTIES OF SALINE SOILS AND EFFECTS ON YIELD AND QUALITY OF 'WILLIAMS' PEAR IN THE UPPER RIO NEGRO VALLEY, ARGENTINA

The objective of this work was to verify the physical and physicochemical properties of saline soils with relationship to the yield and quality of ‘Williams’ pears produced in the Upper Valley of Río Negro, Argentina. The trial was conducted on two parcels (I and II) in a commercial orchard in the 2008-2009 and 2009-2010 seasons. Soils were characterized morphologically and physical and physicochemical variables of the profile were identified. Five plants were selected randomly for the determination of the total yield per plant and the fruit were classified according to the size of the standard commercial box (18.2 kg). On each tree 20 fruit were sampled and analyzed for the following parameters: fruit maturity, fruit weight, fruit size, fruit firmness, soluble solids and total titratable acidity. The soil for plot I was saline (10-15 dS m-1) and slightly rich in sodium at the surface (PSE 20%) but more strongly in the sub-surface layer (PSE 35%). Organic matter was 3.63%. The total yield was 0.028 kg/TCSA. Plot II had a soil salt content similar to plot I, 30% less exchangeable sodium and higher organic matter content (4.32%). The total yield was 0.035 kg/TCSA. Plot II produced more fruit of medium size (100-110-120) and also more small fruit (135-150) than plot I. The correlation between total yield and soluble sodium and total yield and PSE is analyzed, as well as the properties of the fruit produced in plots I and II measured after both analyzed cycles.