Deriving critical loads for the Agra region in India

A steady state mass balance (SMB) method was used to calculate the critical load of S and N for soil. The present load of sulphur (160.6 Eq ha−1 year−1), nitrogen (49.6 Eq ha−1 year−1) and ammonium (172.4 Eq ha−1 year−1) were calculated from wet and dry depositions collected from the Agra region. The values of the critical load of S and N for soil with respect to Cenchrus ciliaris (Anjan grass) were 309.2 and 381.8 Eq ha−1 year−1, respectively. The present loads are lower than the critical loads in this region. The critical loads calculated by the SMB method from the experimental data are in agreement with the results obtained from the RAINS-Asia model for this region.