African Journal of Botany

African Journal of Botany ISSN: 2314-9825, Vol. 9 (2), pp. 001-014, February, 2021. © International Scholars Journals

Full Length Research Paper

Eucalyptus camaldulensis Dehnh. Offers Excellent Potential to Reduce NO₃¯ Concentration in Groundwater

Mehrdad Mohammadnia¹ Sayyed Ahang Kowsar² and Che Fauziah Ishak³

^1,2Fars research center for agriculture and natural resources, Shiraz, I.R.Iran.

³University Putra Malaysia.

Accepted 01 December, 2020

Abstract

Geologic and fertilizer N negatively impact the groundwater in the Gareh Bygone Plain (GBP) in southeastern I.R. Iran. Moreover, the floodwater used since 1983 for the artificial recharge of groundwater (ARG) to alleviate the water crisis in the GBP contains 60.30 ± 21.60 mg L^-1 geologic NO₃¯ on average. This has the potential to intensify the contamination. As the Agha Jari Formation, which supplies the NO₃¯contaminated runoff, covers 27680 km² in the southern I.R. Iran, an untold number of people will be affected with nitrate poisoning where such waters are inevitably used for the ARG. Dissolved NO₃¯ concentrations were monitored monthly for a year in 30 shallow wells in a sandy-gravelly aquifer in the GBP to quantify the effects of different landuse and Eucalyptus camaldulensis Dehnh. on nitrogen retention. A laboratory experiment was also conducted to verify the potential nitrate absorption of the eucalyptus and NO₃¯ surface adsorption potential of the calcareous sand. Our results suggest that landuse and management practices significantly impacted groundwater NO₃¯ (P<0.05), EC (P<0.01), and its pH (P<0.05) in the GBP. Floodwater NO₃¯ was highly reduced when passed through the vadose zone where NO₃¯ was absorbed by the eucalyptus roots and adsorbed by the free CaCO₃ in the calcareous alluvium. The amount of NO₃¯ retained by the roots was 770 fold the amount retained by the free CaCO₃ particles on the surface area basis_. Therefore, establishing forested filter zones within the ARG systems using more efficient and native plant species supplies safer drinking water for rural inhabitants and desert-dwellers.

Keywords: Eucalyptus camaldulensis Dehnh, NO₃¯ Concentration in Groundwater.