Simulation of Nitrogen Leaching Loss in Irrigated Rice Fields

Abstract

The intensive agricultural production in the state of Punjab has resulted in higher N03-N concentration in ground water due to over use of agro-chemicals, which leads to ground water pollution. The LEACHM model developed by Wagenet & Hutson (1992) was modified and used to predict the nitrogen leaching losses from nitrogenous fertilizers in Rice fields. The nitrogen transformations considered are enzymatic hydrolysis of urea, nitrification and denitrification, all represented by first order kinetics. The total measured cumulative nitrogen leaching loss on 95th day after the transplanting of nursery of paddy was observed 32.2 per cent and 29.6 per cent at 60 cm and 90 cm depth below the ground surface, respectively. The model-estimated nitrogen leaching losses at 60 and 90 cm matched fairly well with the observed values in the field. The paired t- test showed that there was no significant difference between the measured and the estimated values at 5 per cent significance level.