Improvement of Soil Biology and Rice Yield in Peat Land Ecology Using Aqueous Extract of Costus Afer: Soil Regenerative Agriculture under Rice Cropping

Abstract

Conventional chemical fertilizer is harmfulness for the ecology and agriculture sustainability especially, in marginal agroecosystem of peat land (Histosol) which requires safeguarding for its’ potential of carbon sequestration however. Aqueous extract of Costus Afer was proposed as alternative input for rice production on peat land in South Côte d’Ivoire: a first trial was laid out with five (5) rates incrementing by 166.66liters/ha up to 666.66 applied in three splits (T4) and once (T5). Rice variety named VA6 was transplanted (20 cm × 20 cm) for three cropping cycles. A second trial was conducted during single cropping cycle adding the conventional fertilizer practice (T6) for the profitability assessment. Treatment induced high variability of rice grain yield (9.36 – 2.21 tha-1) during the Trial 1 and across both while, the yield was almost stable by treatment across cropping seasons (1-3) with significant effect for T4 and T5. Grand mean of rice yield recorded for both trials revealed lowest value for T6 (2.32 tha-1) while Costus solutions have induced more than 3.00 tha-1 and highest profit (293500 FCFA/ha) accounted for T5 with a net gain of 130 000 FCFA/ha/cycle according to Trial 2. There was a significant effect of the treatment on soil structural stability index recording a slight increase under Costus practice while soil pH (6.3 – 6.4) was favorable to bacteria, fungi, spore and endogenic cast of lumbric. Hence, the study supported the use of aqueous extract of Costus Afer as alternative input for regenerative agriculture especially, for rice cropping on peat land. However, the optimum rate should be more explored by further study