Improving soil chemical properties and okra (Abelmoschus esculentus) yield through complementary applications of biochar, and organic and inorganic fertilizers.

In spite of okra's importance to food security in developing countries, its production is limited by low soil nutrient and health status. A screenhouse study examined soil chemical properties, okra growth and yield under complementary application of biochar, organic and inorganic fertilizer in an Ultisol. The treatments comprised 5 kg soil each amended with 5 t biochar ha−1, 5 t poultry manure compost (SPM) ha−1, urea at 56 kg N ha−1, urea (28 kg N ha−1) + 5 t biochar ha−1, 5 t ha−1 (2:1, PM: biochar) (SPMB), urea (28 kg N ha−1) + 5 t ha−1 (2:1, PM: biochar) (SPMBF2). The treatments, replicated thrice, were arranged in a completely randomized design. There were two sets of plants terminated at 50% flowering (dry matter yield (DMY) and nutrient uptake) and at 10 wk post-planting for growth and yield determination. Results revealed that soil chemical properties, okra growth and yield increased responsively to the organic amendments. The SPM, followed by SPMB and SPMBF, enhanced soil pH (0.18–0.19 unit), total N (79–100%), organic carbon (75–100%), available P (55–58%) and exchangeable cations over the control and others (p < 0.05). These treatments also increased the plant's agronomic parameters: plant height (10–19%), number of leaves, leave area (21–31%), stem girth (33–51%), DMY (59–67%), and tissue Ca, Mg and K. The SPMBF2 – treated soil had the highest fruit yield (45 g pot−1). Conclusively, sole and complementary applications of biochar and compost improved soil chemical properties, and okra growth and yields. [ABSTRACT FROM AUTHOR]