NF desalinated water ‘improves marginal agriculture’

Agricultural experiments conducted at Ben-Gurion University of the Negev in Israel consistently show that irrigation with desalinated water promotes a higher productivity of resources such as water and inorganic fertilizers per unit of marketable yield compared with current practices.

Crops grown at the Josefowitz Oasis Project with desalinated water at a 25% lower irrigation and fertilizer rate than best-practice brackish water irrigation guidelines did not show any detectable detrimental effect on the marketable yield. On the contrary, yield increases were observed for sorghum and millet.

Dr Andrea Ghermandi of the Zuckerberg Institute for Water Research (ZIWR) presented a paper on the research at the recent European Desalination Society conference in Barcelona. His research colleagues were Drs Rami Messalem (ZIWR), Rivka Offenbach, and Shabtai Cohen (Central and Northern Arava R&D).

According to Ghermandi, in the Middle East the lack of freshwater promotes the exploitation of marginal quality sources such as brackish aquifers, but the sustainability of the current management practices is questionable.

An agricultural facility aimed at the environmentally sustainable production of crops in arid environments was built and tested at the Yair agricultural research station in Hatzeva, Israel. The facility relies on solar-powered desalination with nanofiltration (NF) membranes to treat the local brackish water and produce high-quality irrigation water.

Using NF membranes allows for less pumping energy and yet supplies the plant with essential elements. Red beet, a salt-tolerant crop, is grown with the concentrate stream eliminating the need for its disposal and with potential net economic benefits.

Agricultural experiments with variable irrigation water quality and application rate for four different staple crops were conducted over two growing seasons between September 2010 and June 2011. The desalination plant operated at low pressure and energy consumption with little maintenance over the whole period.

The experiments were conducted in the Arava Valley of Israel, south of the Dead Sea. The Arava basin is extremely arid and its agricultural activities rely extensively on brackish groundwater from the local aquifers.

Further research at the agricultural facility in Hatzeva is currently focusing on achieving even higher water savings and on the economic viability of the system with different crops and water salinities.