Summary
Agropastoral systems in mountainous regions of northern
Tunisia are undergoing profound transformations related to the changes that are
both on the social and economic organizations and cultural practices. As part
of study of the following areas Zaghouan Siliana and Beja, this work showed the
importance of introducing the cultivation of legumes mainly sulla (Hedysarum
coronarium L.) variety Bikra 21 in the farming systems in mountain areas
especially for small farmers. The field survey on the practice of crop rotation
in Tunisian mountains and the typology of the farms showed that the propitious
profiles for the practice of rotation are among the farmers using this
profession more than a decade, married, 40 years old and has an elementary
school level or more. The environment for the rotation is represented by the
landlord and whose principal activity is farming, located within 10km of the
weekly market, and browsing a paved or a semi paved road. The model for mixed
farming (cattle, sheep or both), having a plain or a sloping topography with a
sandy soil or clay, a useful surface of over then 10 ha profile is favorable
for the practice of rotation. This situation is found in 25.7, 16.4 and 15.4%
of cases respectively in Beja, Siliana and Zaghouan. The multivariate analysis
allowed a better understanding of the nature of links between the different
production parameters of a given region, showing that the farmers in Zaghouan,
Beja and Siliana are characterized by a knowledge of the rotation type growing
up, respectively, absent, low to medium. The performance analysis of Bikra 21
has shown the ability of the variety to adapt climate, soil and social area
contexts. The growth rates of the vegetation of sulla for mowing and grazing
varied between 0.176 and 1.236 cm / mm of rain. The dry matter yields of sulla
are obtained between 974 and 5490kg DM / ha. The efficiency of water use by
sulla varies with the order and the operating way between 0.77 and 4.58 kg
MS/m3 for mowing and 0.78 and 4.11 kg MS/m3 Rain for grazing. The energy
production of prairie of sulla is between 828 and 4666UFL/ha. Operating
techniques of sulla, give it the status of a cleaning plant. Trials of
treatments of sulla wet, showed that the positive effect of the bursting of the
stems only appears after 48 hours wilting for silage from a sulla 1st and 2nd
years respectively without and with reversal .
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The technique of wilting stems bursting with saves free dry
matter and good silage for fodder conservation. Chemical analysis showed that
only ERP31 sulla silage-2, RP31-2, EP31-2 and RP21 are classified as excellent
silage. Comparative testing of artificial rain simulation cumulative 170 mm in
60 minutes between patches of sulla, durum wheat (Triticum durum
Desf.) and unworked fallow, with slopes ranging from 4 , 8 and 12%, have
revealed that the installation of sulla has created a stream of water from 1.2
to 5.8 while for the unworked fallow water loss ranged from 6.3 to 36.21.A 12%
slope, runoff rates were 3.4 et 23.2% respectvely for sulla and durum wheat .
Under the same conditions, the sulla promotes water infiltration by 99%,
against 76.6% for durum wheat. Compared to the unworked fallow, a cover based
on sulla on a slope 12% reduced by 10 times the amount of soil eroded. In the
sediment loads carried by rainfall erosion, clay represents 55% of the total,
with a nitrogen content of 32ppm, and organic matter content of 3.5%.
Therefore, improved vegetation cover and the organic state land tends to
revitalize and especially secure areas of grain production, fodder and
livestock.
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