Slope aspect influences α-tocopherol, β-carotene, ergocalciferol contents and nutritive values of six clover species {Trifolium sp.)

The aim of this study was to determine α-tocopherol, β-carotene, ergocalciferol contents and some nutritive values of six clover species, namely, hare's-foot clover, field clover, suckling clover, narrow-leaved clover, mountain clover and purple clover, collected from different slope aspects (north-facing and south-facing slopes) of natural flora. Slope aspects affected all the β-carotene, α-tocopherol and ergocalciferol, crude protein, some mineral contents and cell wall components of clover species, and their interactions. The β-carotene (282.97 mg/kgDM), α-tocopherol (117.04 mg/kgDM) and ergocalciferol (8.92 μg/kgFM) contents were found to decrease significantly on the north-facing slope. The CP contents ranged from 17.90–22.0% and were higher in purple clover (22.0% DM) and narrow-leaved clover (21.67% DM) on the mountain's south-facing slope than other clover species. The south-facing slope aspect showed the highest ADF (25.14%) and ADL (4.45%) contents in hare's-foot clover, whereas NDF content (35.93–36.72%) had its highest contents in the field and hare's-foot clovers on this same site. For K content, mountain clover samples on the south-facing slope had the highest content (3.03%), while the other five clover samples had lower levels. Suckling and narrow-leaved clovers on the north-facing slope had significantly lower Ca contents (1.88–1.97%) than in the other four clovers. The P contents in mountain clover (0.23%) and hare's-foot clover (0.25%) on the north-facing slope were lower than that in the field, suckling, narrow-leaved and purple clovers on the same site. The suckling clover had the lowest Mg content (0.20%) on this slope aspect. It was concluded that a-tocopherol, P-carotene, ergocalciferol contents and other nutritive values of hare's-foot clover, field clover, suckling clover, narrow-leaved clover, mountain clover and purple clover were affected by slope aspect. Further, south-facing slope had positive effects on the mineral and vitamine contents of these clovers.