Author(s): Isa Ahmed Ghanim, Abdul Aziz Mohamed Abdul Kareem, Ahmed Ali Salih and Asudullah Al Ajmi
Article publication date: 2013-12-01
Vol. 31 No. 4 (yearly), pp. 269-275.
256
Keywords
Aphids, Leafhoppers, Plant bug, Natural Enemies, Tertiary Treated Water, Alfalfa, Cadmium (Cd), Lead (Pb).
Abstract
This study was conducted during the period April 2009 to March 2010 in the Northern Governorate, Kingdom of Bahrain to study the relation between water quality and Nitrogen, Phosphorus, Cadmium and Lead contents of alfalfa crop and insects living on it. The study was conducted on 6 farms, 3 irrigated with underground water and the other 3 irrigated with tertiary treated sewage effluents (TTSE). Plant samples were collected during April in 5 replications, randomly from each farm using a 25×25 cm metal frame for estimation of Nitrogen using (Kjeltec apparatus 2300), and Phosphorus by (Spectrophotometer), Cadmium and Lead content by (Atomic Absorption Spectrophotometer). Pitfall traps and sweeping nets were used to collect insects for analyses for Lead and Cadmium content. Results indicated that water type did not affect alfalfa, Nitrogen and Cadmium contents. Average Nitrogen content was 2.6 and 3% in alfalfa irrigated with groundwater and (TTSE), respectively. And Phosphorus content was 0.33 and 0.4% in alfalfa irrigated with ground water and (TTSE), respectively. Results also showed that irrigation with (TTSE) did not significantly affect Cadmium and Lead contents in alfalfa crop. The average concentrations of these two elements were 0.41 and 0.35 ppm, respectively, their concentrations in alfalfa irrigated with TTSE were 0.44 and 0.34 ppm, respectively. The concentrations of Cadmium and Lead in insects living on ground water irrigated alfalfa were 0.14 and 0.063 ppm, respectively, and in TTSE irrigated alfalfa were 0.338 and 0.076 ppm respectively. Cadmium and Lead concentrations were found to increase in the natural enemies of insects living on alfalfa irrigated with (TTSE) indicating biomagnification of those heavy metals in the food chain from alfalfa to insect pests and predators.