Piling up reactive nitrogen and declining nitrogen useefficiency in Pakistan: a challenge not challenged(1961–2013)

Abstract

Excessive nitrogen (N) application and reduced nitrogen use efficiency (NUE) are the key reasonsbehind N notoriety worldwide, including in Pakistan. We estimated the changes in NUE of Pakistanby calculating the N budget of Pakistan’s agriculture during the last 53years (1961–2013). A more thanten-fold increase in N input (including N fertilizer, biological N fixation, manure, and atmosphericdeposition) from 408 GgNyr−1(1961–1965) to 4636 GgNyr−1(2009–2013) highlights the fact thatPakistan is experiencing a massive expansion of N consumption. Significantly declining NUE (from58% to 23%) and sharply increasing surplus N (171 GgNyr−1to 3581 GgNyr−1) may cause N-relatedenvironment problems in the future if not handled immediately. Escalating gaseous N emissions ofNH3,N2O, and NO (70, 10, and 1 GgNyr−1to 1023, 155, and 46 GgNyr−1, respectively) is alreadyposing a serious threat in terms of impaired air quality. There is a dire need to devise/adapt strategiesand consistent policies for improving NUE, using proper management approaches at the grass rootlevel and applying appropriate legislative measures for judicious N use as per crops requirements.Moreover, promotion of a balanced use of fertilizers would help in improving NUE in agriculture.