Slow Release Fertilizers or Fertigation for Sugarcane and Passion Fruit Seedlings? Agronomic Performance and Costs

Abstract

The aim of this study was to assess the agronomic performance and costs of slow release fertilizers and fertigation in the production of sugarcane and passion fruit seedlings in tubes. Two experiments were carried out simultaneously, one with sugarcane seedlings (SP80-3280) obtained from stalks with one bud (4 cm) and the other with passion fruit (FB-300) from seeds. Both experiments were conducted in 200-cm3 tubes filled with composted pine bark-based substrate, with six treatments: (1) control; (2) standard fertilization (g 100 L−1 of substrate), (NH4)2SO4 (300) + KCl (200) + magnesium thermophosphate (200) + Osmocote® 15-9-12 Plus (600) + Osmocote® 19-6-10 Mini-Prill (600); (3) Osmocote® 15-9-12 Plus (600 g 100 L−1 of substrate); (4) Osmocote® 19-6-10 Mini-Prill (600 g 100 L−1 of substrate); (5) complete fertigation (g 100 L−1 of water), Ca(NO3)2 (80) + KNO3 (50) + MgSO4 (35) + (NH4)3PO4 (10) + ConMicros® Standard (2.5); and (6) macronutrient fertigation, equal 5. except ConMicros®. The results were as follows: (1) sugarcane (70 days) and passion fruit (52 days) seedlings were larger in the fertilized than control tubes; (2) standard fertilization, Osmocote® Mini-Prill, or Osmocote® Plus produced sugarcane and passion fruit seedlings with greater mass; (3) fertigations were the most inexpensive fertilizations; and (4) the slow release fertilizer Osmocote® 19-6-10 Mini-Prill presented larger seedlings, but it cost more (2–3 times) than fertigation. Substrate fertilization is essential for sugarcane and passion fruit seedlings’ production in tubes because the substrate itself is not able to provide enough nutrients for seedling development, and although standard fertilization and slow release fertilizers (Osmocote®) allow to produce larger seedlings, they are more expensive than fertigation.