The Manga located, in the South-East of Niger knows wind erosion. This form of degradation favored the creation of sharp dunes. To remedy this situation, programs to fight against sand dunes are implemented. This study is conducted in Guidan Kadji (Maïné-Soroa). It compares the herbaceous flora of a treated dune that has received manure, a natural course and a living dune in the vicinity of Guidan Kadji. The method of aligned quadrat points was used for the phytosociological study. The treated dune has 24 species, 10 species for the natural course and 3 species for the living dune, the best represented families are the Poaceae with 9 species. Therophytes occupy more than 80% of the gross and weighted spectra. The species. Guineo-Congolese-Sudanese-Zambézian is the dominant phytogeographic type with more than 70% in the gross and weighted spectra. The cover is 4.25%, 71.02% and 95.81% for live dune, treated dune and rangeland respectively. The qualified forage is 1339.65 kg DM/ha or 1.33 T DM/ha for the natural dune versus 703.44 kg DM/ha or 0.70 T DM/ha for the treated dune. It is practically null (2.04 kg DM/ha or 0.002 T DM/ha) on the live dune. Overall, the regularity (>0.60 bits) is high and the Sörensen similarity (>80%) between the treated dune and the natural course is high. This study demonstrated that dune fixation can restore the flora of degraded dune systems, especially if the site is close to residential areas.

The use of organic manure is very old and practiced both in rainfed cultivation and in horticulture. In Niger it has been reported the presence of another source of organic manure called bat guano which is unknown to the population of the said country. The objective of this study is to describe the sector of guano exploitation in Niger. A series of questionnaires was formulated to describe the system of exploitation and use of bat guano. In addition to the agriculture and environment departments, three groups of stakeholders in the sector, including extractors and sellers, the trader (s) and users of guano were interviewed. The results of the investigations showed that to date, the only production and exploitation site of guano identified is that of Magarawa located in the department of Gouré in the Region of Zinder (Niger). The extraction is done using rudimentary tools (pick, knife, plastic) then bagged 40 and 85 kg. The quantity extracted per year is 332 tons. Marketing is mainly carried out by a single individual and the selling price is 4000 to 5000 FCFA per 85 kg bag of bat guano. The buyers are located in the vicinity of Gouré and the Diffa region, there is also a clientele coming from Nigeria. The users of guano are mainly horticulturalist in oasis basins. One of the biggest buyers is the commune of Guidimouni located in the southwest, 100km from Gouré. We conclude that this exploitation of bald guano is an income-generating activity and requires good organization.