Jhorar, Raj KumarGuru Prem2016-11-292016-11-292006http://krishikosh.egranth.ac.in/handle/1/88072Groundwater samples were collected from different tubewells located in tow villages and field experiments were conducted at a farmer field in village Jhanjrola-khera, district Gurgaon to investigate the occurrence of nitrate in the groundwater.. The surface soil of the study area was loamy, while subsurface soil (8.10 to 10.80 m) belongs to sandy loam. All the samples collected during different time periods showed nitrate concentration of about more than twice the maximum acceptable nitrate concentration for drinking water standards (45 mg L-1) as per the guidelines specified by WHO. Comparison of nitrate concentration in groundwater samples collected during pre and post monsoon periods indicated a slight decrease in nitrate concentration of groundwater during the post monsoon period. The EC of groundwater samples from village Mubarikpur varied from 1.25 to 2.35 dS m-1 while the EC of different groundwater samples of village Jhanjrola-khera was more than 5.91 dS m-1. The average nitrate concentration in the samples collected from village Mubarikpur (61.50 mg L-1) was lower than that of Jhanjrola-khera (83.89 mg L-1). Soil samples were collected from a exploratory bore hole and certain pumping tests were conducted. All the samples were within the low limit for available nitrogen (< 250 kg ha-1) and organic carbon (< 0.4 %), but high in terms of total nitrogen (> 0.06 %). Pumping tests were conducted for both the installed gravel-packed and an existing cavity type tubewells with respect to nitrate concentration in the pumped groundwater. The nitrate concentration did not change considerably with the discharge and time during the pumping tests. Nitrate concentrations in the pumped water varied from 1.54 to 1.59 me L-1 for both the tubewells. The shallow groundwater in the upper aquifer showed less amount of nitrate i.e. 1.44 me L-1 as well as lower groundwater EC of 3.47 dS m-1 against EC 7.41 dS m-1 for the pumped groundwater (bottom aquifer). Average transmissivity and hydraulic conductivity of the aquifer was found to be 239.71 m2 d-1 and 57.07 m d-1, respectively. Average values of storage coefficient, hydraulic resistance and leakage factor was found to be 2.05 x 10-3, 20.47 days and 70.0 m, respectively. Lower nitrate concentration in relatively shallow groundwater as compared to relatively deep groundwater, higher total nitrogen throughout the subsurface profile to a depth of 15 m and wide variation in nitrate content among tubewell water of contiguous villages indicated geological characteristics rather than agricultural practices as the main cause of the occurrence of high nitrate in the groundwater of Gurgaon district.enThesis