Abstract

Soil quality constitutes a major factor for crops growth. This study aimed at determining the sustainable soil conservation practices that would increase maize growth as well as production and improve the soil moisture. Two experimental sites were chosen: Dan localized on Acrisol and Za- zounmè localized on ferralsol. Two cropping seasons were investigated: the long rain seasons of 2018 and 2019. The experimental design was split-plot with four replications. The main factor was tillage with three modalities: no-tillage (NT); ridging parallel to the slope (PR); Isohypse ridging (IR) and the second factor was mulching with four amounts: 0, 3, 5 and 7 t.ha^-1. Tillage, mulch amount and their interaction significantly influenced the soil moisture, maize growth and yield over the two investigated cropping seasons at both sites whereby the highest values were obtained under IR for tillage, 7 t.ha^-1 (for mulch amount) and IR7M (for the interaction tillage x mulch amount). Overall, IR significantly increased the maize growth speed by 8% at Dan and by 16% at Za-zounmè; the maize grain yield by 33% at Dan and by 30% at Za-zounmè and the soil water content by 24% at Dan and 20% at Za-zounmè, in comparison with No-Tillage. An increasing effect of mulch amount was also observed. As far as mulching is concerned, the highest values (in average of LR2018 and LR2019) of growth speed (3.77 cm.day^-1 at Dan and 4.08 cm.day^-1 at Za-zounmè); grain yield (3003.03 at Dan and 3471.09 kg.ha^-1 at Za-zounmè) and soil water content (26.89 mm at Dan and 20.44 mm at Za-zounmè) were observed. This suggests that isohypse ridging associated with an appropriate amount of organic  mulch could be  an  option  to mitigate dry spells and drought and improve local farmers’ income in the area of low rainfall in sub- Sahara Africa.

Key words: Crop residues, tillage practices, conservation agriculture, food security, watershed of Zou.