Sustainable organic substrate production using millicompost in combination with different plant residues for the cultivation of Passiflora edulis seedlings

The use of sustainable organic substrates of recognized quality is essential in the production of seedlings of fruit species. In this context, the present study aimed to formulate different sustainable organic substrates based on millicompost combined with different proportions of locally available organic waste, such as coconut fiber (Cocos nucifera) powder, gliricidia (Gliricidia sepium) and elephant grass shavings (Pennisetum purpureum) for the production of Passiflora edulis seedlings. The organic substrates used were as follows: S1- millicompost; S2- commercial substrate and substrates formulated based on millicompost: S3%–25% millicompost + 25% gliricidia + 25% elephant grass + 25% coconut fiber; S4%–50% millicompost+ 50% elephant grass; (S5) 50% millicompost+ 50% gliricidia; (S6) 50% millicompost+ 50% coconut fiber. At 56 days of sowing, the following morphological parameters were evaluated: shoot dry mass (SDM); root dry mass (RDM); plant height (PH); number of leaves (NL); stalk diameter (SD); root volume (RV); leaf area in cm 2 (LA); seedling vigor (SV) and clod stability (CS). The nutrient contents (N, P, K, Ca and Mg) accumulated in the shoot dry mass of the seedlings were determined after this period. The organic substrates that provided seedlings with significantly higher parameters (P <0.05) of SDM, RDM, PH, NL, SD, RV, LA, SV and CS were as follows: S1> S6> S5. The other substrates (S2, S3 and S4) presented seedlings with morphological parameters similar to each other. In addition, there was a greater accumulation of P, K Ca and Mg (P <0.05) in the shoot dry mass of the seedlings developed on the substrates S1> S6> S5. The substrates S6 and S5 represent two new options of sustainable substrates, being effective in the production of yellow passion fruit seedlings with excellent vegetative growth rates.