Water erosion threatens large areas around the world. Donga is one of the witness of Gully erosion in northern Benin which induces serious threats to the natural habitats. This study was conducted to evaluate soil moisture content in different donga type (microdongas, mesodongas and megadongas) and its variation at different topographic level. The thermogravimetric soil moisture measurement technique was used for moisture estimation on saturated and unsaturated soil. Data were analyzed through ANOVA-test and T-test with SAS software. The results showed that soil moisture content varied according to donga types. On unsaturated soil, higher difference (2.75%, p-value =0.0328) was obtained in mesodongas at the middle followed by megadongas at the middle (2.6%, p-value = 0.034). On saturated soil, higher difference was obtained in mesodongas at the upstream (6.51%, p-value <.0001) at downslope (4.55%, p-value = 0.0032) and in the middle (4.32%, p-value = 0.0328) followed by microdongas at the upstream (2.25%, p-value <.0001). It is expected that this paper will be useful for the researchers looking for soil moisture information in sub arid and subhumid zone at different topographic level to develop afforestation strategies based on species that can make the best use of soil water.

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In agriculture, water has become a limiting factor because of the effects of climate change felt by farmers. This situation seriously compromises agricultural production through pockets of drought, delayed and early cessation of rains and then an increase in the length of the dry season. Aims: This study aims to evaluate the effect of tillage and vegetative mulch on soil physical properties and maize water use efficiency in ferralitic soil of southern Benin. Study Design: The Factorial Complete Randomized Block Design with 4 repetitions was implemented. Place and Duration of Study: The experimental site is located at Allada, in southern Benin, and conducted between May 2017 and July 2017. Methodology: Tillage (No-tillage, flat tillage) and straw mulch rate (0%, 50%, 75% soil cover) and their interaction was been tested during this study. The physical properties of soil and maize water use efficiency were determined. Results: Tillage significantly reduced soil temperature by 2.65% and improved soil permeability by 60%. Tillage also significantly improved water use efficiency for maize grain from 3.88 to 7.88 kg.mm-1.ha-1 and for maize biomass from 12.67to 23.31 kg.mm-1.ha-1. Mulching significantly improved soil moisture from 11.54% to 13.13%, water use efficiency for maize grain from 4.26 to 7.58kg.mm-1.ha-1 and for maize biomass from 14.50 to 22.05 kg.mm-1.ha-1. Mulching also significantly reduced soil temperature by 11%. The combination of tillage and mulching significantly improved water use efficiency for maize grain and biomass production. The highest water use efficiency (8.87 kg.mm-1.ha-1 for maize grain and 25.17 kg.mm-1.ha-1 for maize biomass) was achieved with tillage combined with mulching at 75% soil cover. The interaction between these two factors significantly reduced soil temperature by 11.30% (tillage combined with mulch at 75% soil cover) compared to control (no-tillage and no-mulch). Conclusion: This study showed that tillage and mulching at 50% or 75% soil cover improves soil physical properties and water use efficiency for maize production in the context of climate change.

Aims: Crop production is exposed to climate change phenomenon resulting in change in rainfall amount and long drought spells. Good conservation practices are important in yield improvement. This study aims to assess the effect of tillage and vegetative mulch on maize growth rate, yield and harvest index in ferralitic soil of southern Benin. Study Design: The complete randomized block design (CRBD) with 4 repetitions was implemented. Place and Duration of Study: The experimental site is located at Allada, in southern Benin, and conducted between May 2017 and July 2017. Methodology: During this study, two factors were tested (Tillage and mulch) and 6 treatments have been obtained of combination of two factors level (No-tillage, tillage and 0%, 50%, 75% mulch). The growth parameters, yield parameters and harvest index were determined. Results: The results indicated that tillage and mulching significantly influenced the growth rate, leaf surface and leaf number of maize plants. Tillage increased to 54% the grain yield compared to no tillage whereas 50% and 75% mulch promoted the highest grain yield. Considering the combination of tillage and mulching, LM50 (Tillage + 50% mulch) and LM75 (Tillage + 75% mulch) treatments resulted in about 85% increase of grain yield compared to direct seeding without mulch. Conclusion: These results reflect the importance of soil cover in improving of maize productivity.