H. BEN HASSINE¹*

Z. SAÏDI¹

S. ROUZ¹

¹ Carthage University, Higher Agricultural School of Mograne, 1121, Tunisia

Abstract – For studying assessment of carbonates of surface horizons in terms of soils types cultivated in cereals under rainfall conditions in the North-West of Tunisia, and to search at witch granulometric fraction the fine particles of limestone appertain, twenty points covering the most pedogenic types of these zones, have been sampled at the 0-20 cm and 20-40 cm levels. The forty samples collected have served to determine the limestone contents of soils and to specify their particle size compositions. The results have confirmed the domination of fine particle size and the generalized presence of limestone with less or more important proportions. The comparison of the averages and variances of the obtained results has showed that differences between the values of the two horizons are not significant. This has permitted the use of the averages of the two horizons for the study of this limestone assessment according to soils types. The principal component analysis has especially put in evidence the limestone migration from the surface horizons of the cambisols. The use of method of simple linear regression has showed that the limestone particles are more joined to the fine silts fraction. This dependency can be explained by the fact that the fine limestone fraction would be the most sensible to the attack of the dissolution product (very diluted ammonium oxalate). Even this limestone is more abundant in the fine silts and it is not correlated to the clay and the fine sands, its assessment is generalized on the all particle size dimensions but with variable proportions. Its presence in the clayey fraction doesn’t make any doubt like the particles reactivity theory suppose, but it’s probably the extraction with diluted ammonium oxalate witch would be active preferably on the silts particles much more than the clayey fraction of this limestone.

Keywords: total limestone, active limestone, particle size, fine silts, cereal soils, Tunisia.

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Caractérisation agro-morphologique de trois espèces tunisiennes de Lotus

R. HAJRI^{1, 2*}

H.BELTAIF ³

M. BEN YOUNES¹

¹ Pôle Régional de Recherche Développement Agricoles du Nord Ouest semi-aride, Tunisie.

² Institut Supérieur Agronomique de Chott-Mariem, Univesité de Sousse.

³ Faculté des Sciences de Bizerte, Université de Carthage.

Abstract – This work is part of a forage and pasture legumes genetic resources collection and conservation program. Parameters related to plant architecture, plant height, diameter of the main stem, leaf size, number and length of pods and number of seeds per pod were used for morphologic and biometric characterization of three spontaneous species of birdsfoot trefoil (L. creticus L., L. edulis L. and L. ornithopodioides L.) collected from Thuburbo Majus region located at Zaghaouan governorate in Tunisia. Results indicated significant differences between these three Lotus species. Plants of L. creticus L. have an upright orthotropic architecture which is very suitable for mowing. Lotus edulis L. plants are creepy plagiotrope. They make good soil cover for erosion control. They are also interesting for grazing. The L. ornithopodioides L. plants have a mixed architecture which makes them adaptated for grazing. Producing more pods and seeds, this specie is excellent for forage production and species persistence for pastures.

Keywords: Lotus, genetic resources, Agro-morphological characterization.

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S. FKIRI*^,1,2

F. MEZNI¹

A. OUARGHI³

H. GHAZGHAZI¹

M. LARBI KHOUJA¹

A. KHALDI¹

Z. NASR¹

¹ National Research Institute of Rural Engineering, Water and Forestry, B.P 10, 2080 Ariana, Tunisia

² National institute of agronomy Tunis, BP 48, Tunis 1082, Tunisia

³ Superior Institute of Biotechnology Beja, Street Habib Bourguiba, Beja 9000, BP 382, Tunisia

Abstract – The phenolic compounds and antioxidant capacity of ethanol extracts, obtained from nineteen Pinus nigra provenances growing in Northwestern Tunisia, were invetigated. Phenols (Folin–Ciocalteu method), flavonoids (method based on the formation of a complex flavonoid–aluminium) and tannin (vanillin method) content were evaluated. The antioxidant capacity was determined using both phosphomolybdenum method and free radical scavenging activity (DPPH test). Total phenols ranged from 15.67 to 47.53 mg GAE/g of dry matter. The amount of flavonoids varies from 1.69 to 3.97 mg RE /g. Extracts showed an important antioxidant capacity ranging from 242.50 to 1206.87 GAE en mg/g for the total activity and from 36.08 to 99.05% for the free radical scavenging activity.

Keywords: Pinus nigra Arnold, variability, subspecies, phenolic compounds, antioxidant capacity.

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