IMPACT OF RICE STRAW AS PERIPHYTON SUBSTRATES IN EARTHEN FISH PONDS ON WATER QUALITY
Naglaa I.I. Shalaby1; Niema A. Aly2
and Soha M. Ahmed1
1 Limnology department, Central Laboratory For Aquaculture Research, Agricultural Research Center, Egypt.
2 Fish ecology and biology, Central Laboratory For Aquaculture Research, Agricultural Research Center, Egypt.
|Received 16/ 9/ 2018||
Accepted 28/ 10/ 2018
The present study was carried out in the world fish center during the period from the beginning of May to the end of November/ 2017 to investigate the effect of applying rice straw as Periphyton substrates in fertilized earthen fish ponds on water quality parameters. Six 1000 m3 earthen ponds were divided into two groups each of three replicates. Dry rice straw added to one of the two groups in a rate of 45 kg/pond to be appointed as periphyton substrates (T2), while the other group left without applying rice straw to act as control group (T1). Some water quality parameters (water temp. (T, ºC), dissolved oxygen (DO, mg/l), hydrogen ion concentration (pH), total alkalinity (T. Alk. Mg/l), total hardness (TH, mg/l), Calcium (Ca, mg/l), total dissolved solids (TDS, mg/l), nitrite (NO2, mg/l), nitrate (NO3, mg/l), total nitrogen (TN, mg/l), total phosphorous (TP, mg/l) and Chlorophyll “a” (Chl. “a”, µg/l) were measured fortnightly in source water, as well as in (T1) and (T2) ponds. The most important results obtained at the end of the study were as follow: there were no significant (P < 0.05) differences in the mean average of water temperature among source water and different treatments, while those values of dissolved oxygen, pH values, TDS, NO2, NO3, TN, TP and chlorophyll “a” values in source water were significantly (P < 0.05) lower than those values of both (T1) and (T2) treatments, while those of TH and Ca were significantly (P < 0.05) higher than those values of both (T1) and (T2) treatments. However, all measured parameters were within the acceptable ranges recommended by the international competent bodies. The investigated application found to increase the total count of phytoplankton in the order T1 > T2 > source water, with the dominance of cyanophyceae, while chlorophyceae dominated the other groups of periphyton which attached to rice straw mats.