Physico-Chemical Characterization of Soils for the Promotion of Precision Agriculture in Irrigated Rice Cultivation in the Zio Valley in Togo

Abstract

To sustainably improve rice production in the Zio valley, this study characterized the soils of the developed area. More specifically, the study: (i) determined the Physico-chemical properties of soils and (ii) analyzed the impact of rice cultivation on these chemical parameters. Thirty-six (36) fields of producers were selected and distributed in the 4 villages of the irrigated perimeter: 10 in Kovié, 9 in Mission Tové; 9 in Ziwonou, and 8 in Assomé. The samples were manually collected at a depth of 0-30 cm and analyzed at the soil laboratory of the Togolese Institute of Agronomic Research (ITRA). Physically, the soils are sandy-loamy in Kovié (100%), sandy-loamy in Mission Tové (56%), clayey in Assomé (57%), and Ziovonou (78%). Chemically, the soils are acidic with an average pH of 5.57. They present low (0.89%) and moderate (1.3%) limitation levels respectively for nitrogen and organic matter, very severe for assimilable phosphate (2.3±0.16 ppm), and cation exchange capacity (4.64±0.26 meq/100g of soil) and severe for exchangeable potassium (0.14±0.01 meq/100g of soil). The study also showed a significant decrease in the quantities of Nitrogen, Carbon, Potassium exchangeable, and cation exchange capacity respectively of 57%, 72%, 56%, and 85% compared to 1964. The adoption of cultural practices having a less negative impact on the chemical characteristics of the soil combined with an update of the adapted fertilization formulas become imperatives to ensure sustainable exploitation of the perimeter.