Effect of organic amendments on the chemical properties and carbon mineralization in the oasis soil of arid regions and date yield (Southern Tunisia)
Abstract
The oases constitute highly diversified production systems, with the date palm being their
pivotal species. Due to several threat on these agroecosystems, the improvement of its management
becomes necessary. The specific studied area for this research is the Etilet oasis in Kebili,
southwestern Tunisia.
The experimental protocol involves four treatments, each with three replicates: farm manure
(FM), date palm waste compost (DPC), a mixture of farm manure and compost (FM+DPC),
and a control soil (C). This study aims to investigate the effects of these organic amendments
on soil properties and date yield. The gypsium soils of the Nefzaoua region are characterized
by a very low organic matter content and a deficiency in major elements. The findings indicate
an improvement in nearly all studied physico-chemical properties of the soil when compared to
untreated soil (C). The total organic carbon (TOC) content exhibited a marked increase in the
amended plots compared to the control soil (C), with the combined treatment showing a surge
of over 0.92%. Major soil elements, total nitrogen (TN), phosphorus (P), and potassium (K),
significantly increased following the application of amendments. The combination of farm manure
and date palm compost (FM+DPC) was particularly effective, with nitrogen (up to 0.2%)
and phosphore and potassium levels rising to 123 ppm and 217 ppm, respectively. Furthermore,
the amendments also demonstrated an enhancement in date production with an average of 96
kg/palm foot for the plants amended with combined treatment.
The various applied amendments showed a significant improvement in soil quality, having a
positive impact on date yield, with a preference for the combined amendment (FM+DPC).