Les vertisols de Nouvelle-Calédonie

Cet article présente la distribution spatiale des vertisols en Nouvelle-Calédonie ainsi que leurs caractéristiques morphologiques et analytiques. Trois ensembles sont définis : vertisol calcimagnésien, vertisol hypermagnésien, vertisol sodique et acid

Assessing the effect of organic residue quality on active decomposing fungi in a tropical Vertisol using 15N-DNA stable isotope probing

15N-DNA stable isotope probing (15N-DNA-SIP) combined with 18S rRNA gene-based community analysis was used to identify active fungi involved in decomposition of 15N-labeled maize and soybean litter in a tropical Vertisol. Phylogenetic analysis of 15N-labeled DNA subjected to 18S rRNA gene-based community fingerprinting showed that organic residue quality promoted either slow (i.e. Penicillium sp., Aspergillus sp.) or fast growing (i.e. Fusarium sp., Mortierella sp.) fungal decomposers in soils treated with maize or soybean residues, respectively, whereas Chaetomium sp. were found as dominant decomposers in both residue treatments. Therefore, we have clear evidence that specific members of the fungal community used 15N derived from the two different organic resources for growth and stimulated early decomposition of maize or soybean decomposition. In conclusion, our study showed that 15N-DNA-SIP-based community analyses cannot only follow the flow of N from organic resources into bacteria, but also into the actively decomposing fungal communities of soils

PENERAPAN TEKNIK APLIKASI MOTIF VERTISOL PADA BUSANA PESTA MALAM

Vertisol adalah tanah yang kaya dengan kemampuan mengembang dan mengkerut dengan perubahan kelembaban tanah. Selama masa kering, volume tanah mengkerut, sehingga terjadi retakan tanah yang dalam dan melebar. Berdasarkan sumber ide tersebut, penulis membuat busana pesta malam dengan teknik aplikasi kain dengan motif vertisol. Teknik aplikasi kain diterapkan pada bagian rok secara menyeluruh. Tujuan siaga untuk melihat proses pembuatan dan penerapan teknik aplikasi motif pada busana pesta malam dan hasil jadi teknik aplikasi motif pada busana pesta malam. Proses pembuatan teknik aplikasi motif vertisol pada busana pesta malam menggunakan kain suede dimulai dari membuat desain motif yang sesuai dengan bentuk sumber ide tanah vertisol. Proses penerapan teknik aplikasi motif pada busana pesta malam dimulai dengan menyemat aplikasi pada bahan utama rok kemudian menata motif tersebut sesuai dengan desain. Kemudian dijahit menggunakan mesin jahit dan pada saat menjahit diberi jarak 0,3 cm dari tepi kain. Hasil jadi busana pesta malam dengan teknik aplikasi motif vertisol terlihat mirip dengan sumber ide yaitu tanah vertisol yang membentuk seperti rekahan. Pemilihan bahan dantone warna kecoklatan membuat gaun terlihat unik, indah dan elegan. Vertisol is a land rich in clay with the ability to expand and contract with changes in land moisture. During the dry period, the soil volume shrinks, resulting in deep and widening land cracks. Based on the source of these ideas, the authors make evening clothing with fabric application techniques with the advertiser motif. Fabric application is applied to the approved skirt section. The purpose of this paper is to find out the process of making and applying the vertisol application technique to evening party fashions and the results to be the application of the vertisol motif application to evening party fashions. The process of making vertisol motif application techniques in evening party outfits using suede fabric starts from making motif designs that are in accordance with the shape of the vertisol land idea. The process of applying the vertisol motif technique to evening party outfits starts with pinning the application to the main material of the skirt then arranging the motif according to the design. Then sewn using a sewing machine and when sewing are given a distance of 0.3 cm from the edge of the fabric. The results of the evening party fashion with the application technique of vertisol motifs look similar to the source of ideas namely vertisol land that makes like a crack. Choice of material colors and brownish tones make the dress look unique, beautiful and elegant

Effect of tillage practices on the soil carbon dioxide flux during fall and spring seasons in a Mediterranean Vertisol

In this study, we assessed the effect of conventional tillage (CT), reduced (RT) and no tillage (NT) practices on the soil CO2 flux of a Mediterranean Vertisol in semi-arid Morocco. The measurements focused on the short term (0 to 96 h) soil CO2 fluxes measured directly after tillage during the fall and spring period. Soil temperature, moisture and soil strength were measured congruently to study their effect on the soil CO2 flux magnitude. Immediately after fall tillage, the CT showed the highest CO2 flux (4.9 g m-2 h-1); RT exhibited an intermediate value (2.1 g m-2 h-1) whereas the lowest flux (0.7 g m-2 h-1) was reported under NT. After spring tillage, similar but smaller impacts of the tillage practices on soil CO2 flux were reported with fluxes ranging from 1.8 g CO2 m-2 h-1 (CT) to less than 0.1 g CO2 m-2 h-1 (NT). Soil strength was significantly correlated with soil CO2 emission; whereas surface soil temperature and moisture were low correlated to the soil CO2 flux. The intensity of rainfall events before fall and spring tillage practices could explain the seasonal CO2 flux trends. The findings promote conservation tillage and more specifically no tillage practices to reduce CO2 losses within these Mediterranean agroecosystems. (Résumé d'auteur

Influence of soil type differences on the distribution of DTPA extractable heavy metals in soils irrigated with industrial effluents

This study determined the effects of the application of industrial liquid waste from a textile factory on the distribution of DTPA extractable metals in a Pelli-Eutric Vertisol and an Eutric Fluvisol at Akaki in Ethiopia, classified according to the FAO-UNESCO Soil Classification System. The Fluvisol is slightly basic on the surface and has sandy clay to clay loam texture, while the Vertisol is strongly basic on the surface, and has clayey texture throughout the profile. Application of the industrial liquid waste modified and increased levels of DTPA metals in the treated Akaki soils compared to natural levels in the background soils. The Fluvisol has more DTPA extractable Fe, Mn, and Zn than the Vertisol. Surface Cu, Cd and Ni contents are higher in the Vertisol opposed to the Fluvisol. However, there is more enrichment of these metals within depth, in the Fluvisol. Pb concentrations in the Fluvisol are about twice as much as the Vertisol throughout the profile. Soil solution pH seems to have the greatest influence for most metals. Surface Cu and Ni of the treated Vertisol are more influenced by organic matter, while on the whole CEC has negative influence on metal availability because of competing ions. These metals generally decrease consistently with depth in the Vertisol, while in the Fluvisol the profile distribution is irregular. Leaching due to coarser textural composition and floodplain soil impacted by the contaminated river sediments are responsible for metal redistribution in the Fluvisol than in the Vertisol. There is thus greater risk of metal uptake by vegetables on the Fluvisol than the Vertisol. Key words/phrases: Background soils, contaminated soils, Fluvisol, industrial waste, Vertisol SINET: Ethiop. J. Sci Vol.26(1) 2003: 47-5

L´impact des aires protégées et des utilisations anthropogènes du sol sur la regeneration des terrains boisés à Acacia dans l´est du Burkina Faso

Regeneration success, persistence strategies (seedlings vs. coppicing), and population trend of Acacia spp. were tested under two land-use regimes in eastern Burkina Faso: (i) protected areas shielded to livestock grazing pressure, to logging, and using early annual fire as a management system; (ii) areas with high human impact (heavily and extensive livestock grazing, harvesting for wood and for medicinal plants). Generally, a good regeneration rate of Acacia species was observed in protected areas and a poor regeneration rate in areas with high human impact. Nevertheless, some species affiliated to the subgenus Aculeiferum as A. dudgeoni and A. polyacantha showed a good regeneration under both land use regimes. Juvenile plants less than 25 cm height of A. dudgeoni and A. gourmaensis increased by 116 to 50 % in areas with human impact as compared to their populations in protected areas. With SCD slopes varying from –0.40 to -0.70, the protected Acacia woodland displayed a stable population structure due to abundance of recruitment, and coppicing persistence (more common in the subgenus Aculeiferum) favoured by early annual fire. Consequently, the protected areas are favourable for Acacia woodland regeneration. Conversely, SCD slopes are positive or close to zero in areas of anthropogenic regime and showed a declining population, especially more marked with the subgenus Acacia due to permanent seed and seedling removal by livestock grazing. Nevertheless, the number of seedlings of some species was higher in areas under human pressure than in protected areas, especially for the subgenus Aculeiferum, improving the genetic variability and thus the long-term maintenance of the population. Key words: Acacia, early fire, land use, sudano-sahelien zoneLe statut de la régénération, les stratégies de persistance et la dynamique des Acacia spp. ont été évalués suivant deux modes d’utilisation dans la région est du Burkina Faso: (i) les zones protégées soustraites du pâturage extensif et de la coupe du bois, mais sont parcourues annuellement par des feux précoces ; (ii) les zones à forte impact anthropique (fort pâturage extensif, exploitations humaines diverses). En général, les zones protégées montrent un taux de régénération élevé des Acacia spp. alors que les zones anthropogéniques présentent une faible régénération. Néanmoins, certaines espèces affiliées au sous genre Aculeiferum comme A. dudgeoni et A. polyacantha montrent une bonne régénération dans les deux modes d’utilisation des terres. La population juvénile de moins de 25 cm de hauteur des espèces tel que A. dudgeoni et A. gourmaensis est 116 à 50 % plus élevée dans les zones anthropisées que dans les zones protégées. Avec des pentes de régression variant entre -0.40 à -0.70 dans les zones protégées, les populations présentent une structure stable due à l’abondance des plantules, et des rejets de souches maintenues par les feux précoces (plus fréquent dans le sous genre Aculeiferum). Par conséquent, les zones protégées sont plus favorables à la régénération des formations d’Acacia. A l’opposé, les pentes de régression sont positives ou proche de 0 dans les zones anthropisées montrant des populations peu stables particulièrement pour le sous genre Acacia à cause du prélèvement des semences et des plantules due au pâturage extensif. Néanmoins, les plantules issues de la germination de certaines espèces du sous Aculeiferum sont plus nombreuses dans les zones anthropisées que dans les zones protégées et pourraient améliorer la variabilité génétique pour la conservation à long termes des peuplements. Key words: Acacia, feux précoces, pâturage, utilisation des terres, zone soudano-sahélienn