Statistical Analysis of the Physico-Chemical Characterization of Three Arid Soils in the Hadjer-Lamis Region, Chad

The aim of this study is to carry out a physico-chemical characterization of three arid soils. Soil samples were taken from a horizon of 0-20 cm and analyzed as follows: texture, electrical conductivity, maximum water retention capacity and natural moisture content were determined at the Laboratory of Soils-Water-Plants (LASEP) in Chad. On the other hand, the organic matter rate, soil reaction, total and assimilable phosphorus, total nitrogen, total potassium, CEC, exchangeable bases, and C/N ratio were determined at the National Soil Office (BUNASOL) in Burkina Faso. XLSTAT software version 7.5.2 was used for this work, and tests for comparison of means were carried out using the Fischer method with a threshold of 5%. The results of these analyses give for each soil in this order (% clay, % silt, % sand), Dandi (19.5%, 17.5%, 63%), Karal (17%, 7.5%, 75.5%) and Mani (14%, 7%, 79%), all these three soils have a sandy-silty texture. The organic matter levels obtained overall are low: Dandi (0.68 mg/100 g dry matter), Karal (0.61 mg/100 g dry matter), Mani (0.61 mg/100 g dry matter), these results confirm the aridity of these soils. Total phosphorus levels in Dandi, Karal and Mani are 182.50 mg/100 g, 265.50 mg/100 g and 388 mg/100 g dry matter respectively, while assimilable phosphorus levels are 13.08 mg/100 g, 42.33 mg/100 g and 18.10mg/100g dry matter respectively. The three soils have a slightly basic pH-water: Dandi (8.07), Karal (7.29), Mani (7.03) as for the pH-KCl, they are as follows: Dandi (6.28), Karal (6.33) and Mani (6.03). Soil C/N ratios vary from 7.83 to 17.05, CEC from 12.82 to 23 meq/100 g, electrical conductivity from 160.50 to 666.50 µS/cm and maximum water retention capacity from 34.66 to 45.22%. Moisture levels ranged from 2.77 to 4.40% and saturation levels were Mani (19.50%), Dandi (41.09%) and Karal (53.43%). The sum of the bases, meanwhile, varies as follows Dandi (1205.55 mg/100 g dry matter), Mani (2094.68 dry matter) and Karal (2162 mg/100 g dry matter). The total potassium obtained in each of the soil samples is as follows: Dandi (480.50 mg/100 g of dry matter), Karal (483 mg/100 g of dry matter) and Mani (325 mg/100 g of dry matter) and finally, the total nitrogen content varied from 0.02 to 0.04 mg/100 g of dry matter.