NECTARINE PRODUCTIVITY AND FRUIT QUALITY UNDER SWINE MANURE FERTILIZATION: RESULTS FROM A THREE-YEAR FIELD TRIAL

The disposal of swine slurry is becoming a serious problem due to pollutant effects of the nitrogen and phosphorus content of this material. In order to evaluating the possibility of application of swine effluent as fertilizer for orchards, a field trial has been conducted during 2008-2010. The final results of the trial are presented in this paper. The trial has been conducted in a ‘Spring Bright’ nectarine [Prunus persica (L.) Batsch] commercial orchard in Cuneo province, Northern Italy, on a 1 ha study area following a randomized block design with three replications of five treatments: liquid slurry (LS), covered slurry (CS), solid fraction (SF), mineral nutrition (MN), and an unfertilized control (NF). Optimal quantity of liquid and solid materials and best surface for distribution were also calculated according to soil properties and nutrient requirements of the orchards. Measurements of yield, yield efficiency and crop load were used to evaluate the orchard productivity. Fruit quality was assessed at harvest and after refrigeration (4 to 5°C) storage for ten days in normal atmosphere. According to statistical ANOVA analysis, statistically significant differences have been not shown both for productivity and quality. Also the analysis after ten days of postharvest does not present statistically significant differences. Final results show that there are no differences in orchard productivity and fruit quality using swine liquid manure as fertilizer. Nevertheless longer term applications (more than three years) have to be investigated to confirm these results during the whole lifetime of the orchard.