Influence of agroecological practices on soil fertility in the Savanes region of Northern Togo

Abstract

In the Savanes region of Northern Togo, several agroecological practices and field types are encountered. The objective of the study was to assess the effect of these practices and field types of soil fertility parameters and soil carbon and nitrogen stocks. Six combinations of practices and eight field types were involved. For agroecological practices, soil samples were taken from 0-20 cm to determine soil parameter levels. For field types, samples were taken from 0-5 cm, 5-10 cm, 10-20 cm and 20-30 cm to determine carbon and nitrogen stocks. Soil pits were described at the level of agroecological practice. The results show that the carbon (C%) and nitrogen contents (N%) of the agroecological practices [Cordons Pierreux_Fumure Organique_Association and/or rotation (CP_FO_A/R: 0.630; 0.057), Bandes enherbées_Fumure Organique_Association and/or rotation (BE_FO_A/R: 0.442; 0.050), Association and/or rotation (A/R: 0.516; 0.042) et Fumure Organique_Association and/or rotation (FO_A/R: 0.456; 0.048)] were statistically higher than those of non-agroecological practices [monocultures of Zea mays and Sorghum bicolor (Mono_Cer: 0.331; 0.025) and permanent rice cultivation (Riz_Per: 0.334; 0.023)]. For the other parameters (Assimilable Phosphorus, Exchangeable Potassium, Exchangeable Sodium, Cationic Exchange Capacity, pHwater, pHKCl), levels were statistically identical. In terms of field types, C stocks were higher in hut fields with organic manure (CCsFO) and bush fields cultivated under cowpeas [Parkia Biglobosa (CBN) (8.27 t.ha-1; 9.22 t.ha-1) on 0-5 cm and (36.44 t.ha-1; 30.25 t.ha-1) on 0-30 cm. The C stocks of bush fields with and without organic manure (CBr; CBrFO)], lowland fields with manure and alluvial terrace fields (CTA) were lower. The agroecological practices, organic manuring and agroforestry have a positive effect on soil fertility and soil carbon storage in the Savanes region of Northern Togo.