نتائج سنتين من التجارب الميدانية لإدارة الملوحة في بساتين الفستق

Between 2023 and 2025 we compared three salinity management strategies across four trial plots in a pistachio orchard with saturated-extract electrical conductivity between 6 and 8 dS/m. The aim was to find a strategy that both lowers root-zone salinity and is defensible in terms of water use.

Trial design

1. Control plot: the grower's existing management, unchanged.
2. Plot A: a single heavy winter leaching event.
3. Plot B: leaching split across four applications through the season.
4. Plot C: split leaching combined with granulated gypsum applied at the start of the period.

Main findings

Despite high water use, Plot A produced no durable reduction in salinity; conductivity returned to baseline by mid-season. Plot B performed better, but without structural remediation infiltration remained the limiting factor.

Plot C gave the best outcome: root-zone conductivity down to about 4.2 dS/m by the end of year two, using less water than Plot A. The reason is straightforward — by displacing sodium, gypsum improved infiltration and made leaching more effective.

The economics

The cost of granulated gypsum in Plot C was significant in year one, but counting water saved and the yield gain in year two, payback worked out at under two seasons. In Plot A the extra water, with no durable result, was effectively a net cost.

Limitations

The trial ran at a single site on one cultivar, so generalising the results warrants caution. Irrigation water quality also varied over the period; this is accounted for in the analysis but its effect cannot be fully isolated.