Diyala Journal of Agricultural Sciences, 9(Special Issue): 31-39, 2017 Darwesh et al. 31 http://www.agriculmag.uodiyala.edu.iq/ APPLICATION THE DRIS EQUATION TO ASSESS THE NUTRIENT STATUS OF DUKAN AND DUHOK LAKES IN NORTHERN OF IRAQ Dalshad A. Darwesh1 Yahya A. Shekha Janan J. Toma Environmental Science Department- College of Science, Univ. of Salahaddin, Erbil, Iraq. 1 Corresponding author: dadazeezdarwesh72@gmail.com ABSTRACT This investigation was conducted to study the nutrient status of different lakes and to determine the productivity status of lakes by comparing the results of DRIS approach with the lakes productivity equations. Data for application of DRIS and TSI equations were collected from previous studies for Dukan and Duhok Lakes that conducted at different studies periods while water samples were taken and analyzed during 2013. The results of nutrient index showed that the Dokan Lake was more balance or adequate status of nutrient in 1980 compared with 2014, because there imbalance of nutrients indices recorded lower value (193.60) in 1980 compared with 2014 which attained (413.34). However data analysis was revealed that the lower value of NBI (129.52) was recorded in 2013 in comparison to the higher value NBI in 2000 in Duhok Lake. The DRIS also computed an overall index, which is the sum of the absolute sum of all DRIS indices, the lesser NBI the imbalance among nutrient referred to more productivity. In general the result indicate that nutrient index and nutrients imbalance index showed more balance in Dukan Lake in previous period in comparison with the recent period, vice versa for Duhok Lake. From TSI value revealed that the productivity of Dukan Lake decreased from (56.41) to (53.07) during 1980 and 2014, while the productivity of the Duhok Lake increased from (30.11) to (32.63) during 2000 to 2013. Key words: DRIS, Nutrient status, TSI, Dukan and Duhok Lakes. INTRODUCTION The trophic status referred to the level of productivity in a Lakes as measured by phosphorus, algal abundance, and depth of light penetration. Trophic status in clean lentic water based on amount of biological productivity occurring in the water (Chandrashekar et al., 2014). High nutrient concentrations in aquatic ecosystems can results in increased primary production (Dodds and Whiles, 2010). Higher primary productivity is not necessarily a predictor of poor ecological condition as it is natural for Lakes to shift from lower to higher trophic states but this is a slow process (Sullivan and Reynolds, 2004). Bioavailable nutrients, are generally thought to control primary production, or Received: 17/1/2016 Accepted: 23/1/2017 http://www.agriculmag.uodiyala.edu.iq/ mailto:dadazeezdarwesh72@gmail.com Diyala Journal of Agricultural Sciences, 9(Special Issue): 31-39, 2017 Darwesh et al. 32 http://www.agriculmag.uodiyala.edu.iq/ organic matter production, in lakes and reservoirs, light, temperature and micronutrients are important factors contribute to primary production (Novotny and Olem, 1994). As nutrient concentration and primary production increase, the water body classification can change from oligotrophic, mesotrophic, eutrophic and finally hypertrophic (Mahesh et al., 2014). Using the index, one can get a quick idea about the extent of productivity of a Lake (Sharma et al., 2010).The enrichment of bodies of water is associated with increased primary production and the occurrence of episodes of excessive development of algae or aquatic macrophytes, which may affect the use of the water for different purposes and for the protection of aquatic life (Santos et al., 2014). Trophic state index (TSI) that retains the expression of the diverse aspects of the trophic state found in multi-parameter indices yet also has the simplicity of a single parameter index, for water quality assessment of impounded water bodies was proposed by (Carlson, 1977). Carlson’s trophic state index can be computed from any of the three interrelated water quality parameters: Secchi disk depth (SDD), chlorophyll-a concentration (Chl a), and total phosphorous measurement (TP). The index has been widely accepted owing to its calculation simplicity and ability to communicate between researchers, government agencies, and local community residents (Cheng et al., 2001). The diagnosis and recommendation integrated system (DRIS) is a recent approach for interpreting plant tissue analysis indices. The DRIS proposed by (Beaufils, 1973) has been used The DRIS index scale that results from those calculations is continuous and easy to be understood (Walworth et al., 1986). This model is designed to determine when the nutrient contents of crops are excessive (positive indices), adequate (zero indices) or deficient (negative to determine the balance of N, P, K and S in wheat plant. Also many investigators has been studied DRIS approach like, (Sevenson et al., 1988; Hanson, 1981; Mackay et al., 1987; Al-Khafaji, 1993; Caldwell, 1994; Soltanpour et al., 1995; Esmail et al., 1999; Sultan, 2005; Darwesh, 2007). Most of these study were carried out on plant and soil, while the DRIS equation has not applied to study the nutrients status of water body in Kurdistan region, thus the objectives of this investigation was to evaluate the nutrient status of different lakes and to determine the productivity of lakes by comparing the results of DRIS approach with the lakes productivity equations. http://www.agriculmag.uodiyala.edu.iq/ Diyala Journal of Agricultural Sciences, 9(Special Issue): 31-39, 2017 Darwesh et al. 33 http://www.agriculmag.uodiyala.edu.iq/ MATERIALS AND METHODS Data collection Data for application of DRIS and TSI equation were collected from previous studies for Dukan Lake (Shaban, 1980; Goran, 2014), for Duhok Lake from (Al- Nakshbandi, 2000), while samples were collected and analyzed for Duhok Lakes ( during 2013). Samples collection Water samples were taken in a clean polyethylene bottle from Duhok reservoir in different seasons during 2013 at three sites. Water transparency was measured by using Secchi disk. Total phosphate was measured by using persulphate digestion method, while chlorophyll- a determined by using acetone extraction procedure the absorbance were measured by spectrophotometer, total dissolved nitrogen using potassium persulphate (K2S2O8) as described in (APHA, 1998; Bartram and Balance, 1996). Study area The Dohuk dam is an earth-fill embankment dam (latitude: 36º 52′ 33″ N; longitude: 43º 00′ 13″ E). It was built on the Dohuk River just north of Dohuk city, Iraq. The dam was completed in 1988 with the primary purpose of providing water for irrigation. It is 60 m height and can withhold 52,000,000 m3 of water. The dam has a bell-mouth spill way with a maximum discharge of 81 m3/s. maximum length of reservoir is 4km and maximum width is about 1.7km, with maximum depth of 60m (Shekha et al., 2013) (Figure 1). The Dukan Dam is a multi-purpose concrete arch dam in Sulaymaniyah Governorate, Iraq (latitude: 35º 57′ 15″ N; longitude: 44º 57′ 10″ E). It impounds the Lesser Zab River, thereby creating Dukan Lake. The dam was built between 1954 and 1959 as a multi-purpose dam to provide water storage, irrigation and hydroelectricity. It is 116.5m height and can withhold 6,970,000,000 m3 of water. The catchment area is 11,690 km2 and surface area is about 270 km2 (Goran, 2014) (Figure 1). These equations (equation 1, 2, 3 and 4) were originally based on Carlson trophic static indices (Carlson, 1977). (Kratzer and Brezonik, 1981; Popovicova and Celi, 2009; Rahul et al., 2013). TSI (SD) = 60.0 − 14.41 ∗ ln(SD) [1] TSI (TP) = 14.42 ∗ ln(TP) + 4.15 [2] TSI (Chl) = 30.6 + 9.81 ∗ ln(Chl) [3] In which The TSI based on TN data was calculated using (Zbierska et al., 2015) equation: http://www.agriculmag.uodiyala.edu.iq/ https://en.wikipedia.org/wiki/Embankment_dam https://en.wikipedia.org/wiki/Dohuk,_Iraq https://en.wikipedia.org/wiki/Spillway https://en.wikipedia.org/wiki/Arch_dam https://en.wikipedia.org/wiki/As_Sulaymaniyah_Governorate https://en.wikipedia.org/wiki/As_Sulaymaniyah_Governorate https://en.wikipedia.org/wiki/Iraq https://en.wikipedia.org/wiki/Little_Zab https://en.wikipedia.org/wiki/Lake_Dukan https://en.wikipedia.org/wiki/Irrigation https://en.wikipedia.org/wiki/Hydroelectricity Diyala Journal of Agricultural Sciences, 9(Special Issue): 31-39, 2017 Darwesh et al. 34 http://www.agriculmag.uodiyala.edu.iq/ TSI (TN) = 54.45 + 14.43 ∗ ln(TN) [4] Carlson’s trophic state index (CTSI) = [TSI (TP) +TSI (CA) +TSI (SD)]/4 Where SD = Secchi Depth (m), TP = Total Phosphorous (µg/l), TN = Total Nitrogen, Chl = Chlorophyll (µg/l). The nutrients indices were calculated by using the following index equations by (Hallmark et al., 1987): N index= [f (N/P) +f (N/K) +f (N/Ca) +f (N/Mg) +f (N/Na) +f (N/S) +f (N/Chl)]/n P index= [-f (N/P) +f (P/K) +f (P/Ca) +f (P/ Mg) +f (P/Na) +f (P/S) +f (P/Chl)]/n K index= [-f (N/K) -f (P/K) +f (K/Ca) +f (K/Mg) + f (K/Na) +f (K/S) +f (K/Chl)]/n Ca index= [-f (N/Ca) -f (P/Ca) -f (K/Ca) +f (Ca/Mg) + f (Ca/Na) +f (Ca/S) +f (Ca/Chl)]/n A C B N N N Figure 1: Show map of: A- Northern part of Iraq, B- Duhok dam in Duhok city, C- Dukan dam in Sulaimanyah Governorate (Google Earth) http://www.agriculmag.uodiyala.edu.iq/ Diyala Journal of Agricultural Sciences, 9(Special Issue): 31-39, 2017 Darwesh et al. 35 http://www.agriculmag.uodiyala.edu.iq/ Mg index= [-f (N/Mg) -f (P/Mg) -f (K/Mg) -f (Ca/Mg) +f (Mg/Na)+f (Mg/S) +f (Mg/Chl) /n Na index= [-f (N/Na) -f (P/Na) -f (K/Na) -f (Ca/Na) -f (Mg/Na) +f (Na/S) +f (Na/Chl)]/n S index= [-f (N/S) -f (P/S) -f (K/S) -f (Ca/S) -f (Mg/S) -f (Na/S) +f (S/Chl)]/n Chl.index= [-f (N/chl) -f (P/chl) -f (K/chl) -f (Ca/chl) -f (Mg/chl) -f (Na/chl) -f (S/Chl)]/n The functions were calculated by using the following equations: f(A/B)=[(A/B)/(a/b) -1] (100/CV)when A/B>a/b, f(A/B)= [1- (a/b)/(A/B)] (100/CV)when A/B