Fertilizer application and chemical fertility of a lixisol in a crop rotation system in the southern Sudanian zone of Burkina Faso

Abstract

The lack of organic matter in soils and the high cost of mineral fertilizers are constraints to the intensification of agricultural production in Burkina Faso. The aim of this study is to evaluate the effects of the joint application of organic and mineral matter on soil fertility under crop rotation conditions. The study was carried out at the research station in Farakoba, from 2018 to 2020. The system was a 4x4 split-plot factorial with 3 replications. The 4 treatments corresponded to 4 crop rotations used as the main factor and 4 manures as the secondary factor. We used 4 rotation sequences: Sorghum-Fonio, Soya-Fonio, Mung bean-fonio, Sorghum-Mung bean. The four secondary treatments corresponded to four fertilizers: control with no fertilizer application; NPK and urea; Compost+poultry manure; Compost+poultry manure+Burkina phosphate). Results showed that legume-cereal rotations resulted in a 2.3% drop in C/N ratio, while the total exchangeable base (TEB) and the cation exchange capacity (CEC) increased by 82.53% and 24.08% respectively compared to the soil at the start of cultivation. Compared to the soil at the beginning of the crop, the soya-fonio rotation resulted in CEC and TEB increases of 26.87% and 86.55% respectively. The Compost+poultry manure treatment recorded significantly higher TEB and CEC contents, followed by the Compost+poultry manure+Burkina Phosphate and Compost+NPK+Urea treatments. Compared to the Compost+NPK+Urea treatment, the Compost+Poultry manure +Burkina Phosphate treatment resulted in TEB and CEC increases of 18.7% and 5.06% respectively. The results showed a negative and non-significant correlation between C/N and the parameters Ca, Na, Mg, TEB, CEC and saturation level. On the other hand, the correlation between C/N and K was positive and non-significant (r=0.036). In a context of high mineral fertilizer costs, fertilization techniques and productivity of systems can therefore be improved by combining local fertilizing resources such as poultry manure, Burkina phosphate and legume rotations.