Effects of cover crops species on Passiflora edulis nutrition

This work was carried out to evaluate the impact of cover crops species in the nutrient cycling, soil quality, and passion fruit (Passiflora edulis; PF)-productivity. The treatments consisted of four leguminous species: forage Arachis pintoi, Crotalaria spectabilis, Canavalia ensiformis, Cajanus cajan, cultivated in the interrow area, plus a control treatment (spontaneous species). In the first year, there was a significant effect of the cover crop on PF fruit production and on phosphorus (P), sulphur (S) and copper (Cu) concentration in leaves. The highest fruit productions were observed in the A. pintoi and the control treatments. The highest concentration of P was found in PF plants cultivated with C. ensiformis. Nevertheless, neither colonisation of plant roots by vesicular-arbuscular mycorrhizal (AM) fungi nor soil phosphatase activity, nor soil P content could explain the differences in the tissue P concentration. The cover crop and PF plants increased the number of AM spores in the soil. C. spectabilis negatively affected the S content in PF plants tissue. The fruit production was significantly correlated with the content of S in tissue, but not with the soil sulfatase acitivity. In the control treatment, PF plants accumulated less Cu than with cover crops species. Biochemical parameters such as soil phosphatase and arylsulfatase activities were not significantly different among treatments, which is possibly related to soil fertility. In PF rows, the root-knot nematode Meloidogyne was found to be mainly associated with the C. spectabilis treatment. However, no negative effects on PF fruit production were associated with the presence of this plant-parasite.