Objective: The long-term impacts of conventional tillage through compaction, soil erosion and loss of soil fertility have led to evaluation of this system. To mitigate these problems, simplified cultivation techniques (SCT) are increasingly practiced. The objective of this review is to clarify the effects of conventional tillage and minimum tillage on soil fertility. Methodology and Results: The methodology is based on a documentary research through a synthesis and a confrontation of the researches results of different authors. It is found that, after 5 to 6 years, conventional tillage lowers the fertility of the soil and reduces its productivity. There is a diversity of SCT with convincing results. These techniques leave more agricultural residues and allow an improvement of the indicator of organic matter on the soil by reduction of the mineralization. The STC, such as zero tillage, increase soil fertility and have the potential to reduce greenhouse gas emissions. Improving soil fertility increases yield with a saving in working time. Hydraulic conductivity increases when switching from conventional tillage to direct sowing. Compared to conventional tillage, SCT provide an ideal environment for soil fertility recovery. However, the adoption of SCT and no-till is subject to a constraint on the agricultural equipment used. The design of effective equipment remains the challenge to facilitate large-scale application of SCT. Conclusion and application of results: It is noticed that conventional tillage induce long-term disturbance of soil properties and reduce fertility. Simplified cultivation techniques and particularly a direct sowing have a positive effect on the amount of soil organic matter, its density and water retention, and final production. The specific direct seeder must be designed to accompany the mechanization of these techniques.

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The need to feed the population growth conducts to the development of material intensive production systems in many countries. However the absence of adequate policies has adverse consequences on the environment and the performance of the agricultural and rural sectors. Benin Republic, through its Strategic Plan for Agricultural Sector Development (PSDSA) focuses on improving food and nutrition security, improving farm level income and building resilience to climate change within the Government Action Plan (PAG Bénin Révélé) 2016-2021. The aim of this study is to analyze the current agricultural policies and his link with the current environmental policies in Benin Republic. The data from Ministries and Structures in charge of Agriculture, Environment, Health and Human being were used. Reports from some international organizations such as FAO, PNUD and FIDA were also used. It is observed and planed an increase in cultivation area, all crops yields and crops production from 2016 to 2021. That will involve the more use of agricultural machinery, fertilizers and pesticides. Added to the current environment challenges, it appears the risk of soil degradation, deforestation, water and air pollution, then global impact on the environment when this plan will be implemented. It is right that some Environment Impact Assessment (EIA) are purposed for many of the actions. However, these EIA are sometime neglected and sacrificed for the profitability of agricultural production. To achieve this agricultural goal without affect the environment, the respect of the adequate law and EIA for each single activity becomes necessary.

The deep assessment of agricultural mechanization inside developing countries could help for local action-taking. This study investigates the use of tractors between the poles of agricultural development (PAD) in Benin Republic. Using a multi-stage random sampling procedure and a questionnaire, 203 tractor users were surveyed in 43 municipalities distributed across the seven PADs of the country. Kruskal-Wallis tests were carried out to compare the different poles of agricultural development based on the mechanization level and tractor performances. Student-Newman-Keuls tests were used to structure the means of these variables. The results show a significant variation (P < 0.05) of the mechanization level between the PADs. Apart PAD1, all the poles use greater than 60 % manual equipment. Animal-drawn is most implemented in the northern part of the country (PAD1; 2 and 3). The use of tractors is lower over the country, and the PAD2 and PAD3 are the most users. From PAD4 to PAD7, the combination of manual tillage with animal power or tractor is not well represented, indicating manual tillagebased agriculture in these poles. In general, 53.20% of the users do not have a tractor parking and the repair center is quasi-absent (97.54 %). PAD2; 4 and 3 are most disc plow users. Mechanical sowing is more observed in PAD2 and 7 and absent in PAD1; 3 and 4. Moreover, the harvester is present in PAD2; 4; 6, and 7. On average, the highest mechanized area was 134.56 ha from PAD3, whereas, the lowest, 12.00 ha was found in PAD7. PAD7 spends more on plowing (47670 FCFA) than the other poles. The mechanized plowing is most slower in PAD7 (3.53 h/ha) while much faster at the PAD2 (1.96 h/ha). These results could help decision-makers for accurate actions taking to advocate for agricultural mechanization sectors in the country based on the weakness of each pole of agricultural development.