Influence of soil properties on yield and fruit maturity at harvest of 'Williams' pear

In the Upper Rio Negro Valley, northern Patagonia (Argentina), there is a large variability of soils and the success of a fruit plantation depends mostly on soil characteristics. The main objective of this work was to determine the relationships between yield and fruit internal maturity at harvest of pear trees (Pyrus communis L.) grown in soils with different properties. The soil around each of 30 trees was morphologically characterized by measuring physical, physic-chemical, and chemical variables. At harvest time, total and commercial yields were measured, and maturity was determined by measuring flesh firmness, soluble solids, and titratable acidity. According to edaphic variables, soils were classified into five groups. Yields presented significant differences among such groups and growing seasons. The distribution of commercial sizes was similar in soils with fine texture, and high K content (897 and 663 mg kg-1) and cation-exchange capacity. Smaller fruits predominated in soil groups with high salinity (6.1 dS m-1 in surface and 10.8 dS m-1 in subsurface horizons) and shallow depth. The soil group with the highest salinity presented fruits with 11% more titratable acidity compared to all other groups. The soil group with the smallest depth presented fruits with high levels of flesh firmness (11.18 kg cm-2) and soluble solids (14.8%). The selected set of edaphic variables allowed us to differentiate groups of soils and analyze its influence in pear tree yield, commercial sizes, and fruit internal maturity