The potential role of spineless safflower (Carthamus tinctorius L. var. inermis) as fodder crop in central Italy

The present study aimed at assessing how nitrogen (N) fertilization affects nutritional characteristics of spineless safflower grown under Mediterranean conditions and evaluating a 2-days wilting treatment on moisture reduction and pH before ensiling. Spineless safflower, sown in November 2008, was grown in 3 m x 18 m plot (45 plants m-2). A randomized complete block design (RCBD) one cultivar x four N-fertilization levels (N0=0 kg/ha, land allocation, N1=35 kg/ha, N2=70 kg/ha, N3=105 kg ha-1) (3 replicates each level) was adopted. At mowing (May 2009, before blooming) the crop biomass production was recorded. Wilted plant material for each plot was collected and pH was measured. Dried and ground samples (1 mm mesh) were analyzed for crude protein (CP), lipids (EE), crude fibre (CFom), neutral detergent fibre (aNDFom), acid detergent fibre (ADF), lignin (ADL) and ash (ASH) content. All data were analyzed by ANOVA and difference among means was assessed significant at P<0.05. Biomass production showed a nitrogen-dose relationship [from N0=1.80±0.29 to N3=2.71±0.20 t ha-1 dry matter (DM), P<0.01]. N-fertilization significantly affected the CP content, with the highest values (17.52±0.26% DM) observed for the N3 fertilization level. The other nutritional characteristics (EE: 1.36±0.23% DM; CFom: 41.70±3.65% DM; aNDFom: 44,6±2.71% DM; ASH: 12.74±0.74% DM) were not or only slightly affected (ADF: 34.15±2.14%; ADL: 9.53±2.35) (P<0.05) by the N-fertilization. After the 2-day wilting treatment, the highest pH (5.99±0.08) was found for N2 treatment, while the lowest one (5.85±0.06) was recorded for the N0 level (P<0.01). The wilting treatment gave a sufficient moisture reduction, allowing satisfactory preservation of safflower by ensiling. Spineless safflower shows an interesting potential to be grown for ruminants feeding purposes in Mediterranean area. N-fertilization plays an important role as far as productivity of safflower and its CP content are concerned. Further studies are in progress to fully characterize safflower as fresh and preserved forage resource for crop-livestock production systems in central Italy.