The estimated runoff from the cultivated land of various tehsils in Kharifand rabiseason is presented in Tables 8 and shown in Fig 6. It is observed that total runoff from cultivated land is the maximum in Narkher and minimum in Ramtek tehsil of Nagpur district.

Figure 6: Estimated runoff from the cultivated land of various tehsils

The amount of pollutant generated in agricultural land use of a tehsil unit is the function of different cropping pattern, rainfall variation, fertilizer applied and area under cultivation. Considering the amount of fertilizer applied and fertilizer requirement by different types of crops, the amount of fertilizer used was estimated. The corresponding remaining fertilizer i.e. the excess nutrient load which remains in the soil after Kharifand Rabiseason from each Talukais presented in Tables 9 and 10.

This amount of load generated from each Talukawas classified in different ranges and mapped onto the base map for Kharifand Rabiseason as shown in Figure 7 and 8, respectively. It is seen that most of the Talukas generate nutrient load in the range 2051450 kg To 4081517 Kg per year. The highest load is generated from the agricultural land in Narkher Taluka.

Figure 7: Total nutrient load generated in Kharif season

Figure 8: Total nutrient load generated in Rabiseason

The unused fertilizer is carried with overland flow after the rainfall, which either meets the nearby water body or spreads over the land. The direction of runoff flow from agricultural land is also shown in Figure 5. It is observed that agricultural areas in Narkher, Katol, Bhiwapur and Umrer Talukas do not contribute to water pollution, whereas the areas near Major River Kanhan severely contribute to surface water pollution. This is shown in Figure 9 by creating a buffer zone of 2 km radius around each water body in GIS and mapping slope direction on it. Direction of slope indicates the sensitivity of water body to receive agricultural pollution from adjacent area. It is observed that the water bodies in Narkher, Kuhi and Maunda Taluka, which generates highest pollution load, would receive maximum nutrient loading from agricultural runoff and maximum nutrient loading from agricultural runoff in Narkher goes into the Vardha catchments.

Figure 9: Buffer- zone Map with 2Km distance around water bodies in Nagpur District

The simulated pollutographs i.e. the graphs showing pollutant load carried with runoff after Kharifand Rabiseason in three major talukas which generate maximum agricultural pollution load are presented in Figs 10 to 12. (i.e. pollutograph for TN ad TP.) Since, the fertilizers are again applied in the same proportion at the start of each Kharifand Rabiseason, there is accumulation of nutrient in the soil. The accumulated load is considered for simulation of pollutographs for the next cycle of Kharifand Rabiseason and are termed as projected scenarios. The projected pollutographs for subsequent Kharifand Rabiseason in talukas with highest nutrient loading are also presented in Figures 10 to 12.

Figure 10: Nitrogen and Phosphorus Load in the Runoff from Narkher Taluka

Figure 11: Nitrogen and Phosphorus Load in the Runoff from Kuhi Taluka

Figure 12: Nitrogen and Phosphorus Load in the Runoff from Maunda Taluka