In the first scenario (SCN1) the actual allocation of irrigation supplies were used while the second scenario (SCN2) was generated by using the maximum surface supplies required for crop use.
In the case of Sheikhupura Subdivision, the optimisation results suggested by the SWAGMAN Farm Model for the cropping pattern would increase the gross margins by about 6.7 and 69.00 percent from the current level of Rs 488.86 million to the expected level of Rs 521.90 and Rs 826.39 million for both scenarios, SCN1 and SCN2, respectively.
The SWAGMAN Farm Model results for SCN1 suggested reducing the area under cropping patterns like rice-wheat and Rabi fodder-rice under limited water conditions to about 7.00 and 4.29 thousand hectare, respectively.
The salts brought into soils of the Subdivision by capillary upflow through irrigation, and rainfall during cropping season would be 122.85 and 202.30 thousand tons for both the scenarios, SCN1 and SCN2 respectively.
This shifting of area under different crop rotations gave 6.1 and 29.36 percent increase in gross margins of the Subdivision, raising it from the current level of Rs 961.45 millions to Rs 1020.38 and Rs 1243.70 millions for SCN1 and SCN2, respectively.
In SCN1, the model results showed that rice-wheat and maize-wheat crop rotations were dropped but increased the area under sugarcane and Kharif fodder-wheat by 18.50 and 15.99 thousand hectares, respectively.
For the whole year, the crop water requirement of the cropping pattern proposed by the model was 408281 ML for SCN1 and 991725 ML for SCN2.
Existing gross margins were estimated to be Rs 1609.02 million while projected gross margins would be Rs 1921.64 and Rs 2030.49 millions for both SCN1 and SCN2, respectively.
In SCN1, about 20.96 thousand hectares of land for Kharif fodder-wheat was proposed by the model, which was only 9.55 thousand hectares in the actual scenario.
But due to water constraints in SCN1, the model proposed only 0.11 thousand hectares.