Quantification of nitrogen dynamics and flows and mitigation of its losses in agricultural systems in the Indus basin of Pakistan

Curbing the polluting effect of introducing extra N into the global nitrogen (N) cycle, mainly as fertilizers for agricultural purposes, is identified as one of the major environmental challenges of the 21st century. Nitrogen (N) fertilizer production, transport and use are energy intensive, costly and environmentally polluting. Nitrogen use efficiency (NUE) in cropping systems is very low, often with only 30-40% of applied N being taken off in grain produced and a large proportion of the remainder being lost to the environment. Excess fertilizer N is leached and runs off causing eutrophication of waterways and pollution of groundwater, or lost to the atmosphere as gaseous N species contributing to the greenhouse effect and global warming. Fertilizer N loss also translates to economic losses for farmers. The contrasting situation is the underuse of fertilizers where farmers are mining the soils of nutrients and realizing low yields because they cannot get access to or afford fertilizers. This activity will seek to investigate, quantify and address: (1) fertilizer management and it’s over, inappropriate and under use; (2) N losses due to agricultural activities; (3) N flows associated with run off, leaching and erosion; and (4) fertilizer markets and distribution in the Indus basin, while considering a balance between the various ecosystem services related to food production and environmental quality. The first step in the process will be an assessment of the N flows in the Indus basin based on estimates of N fertilizer inputs and the expected N dynamics in the major cropping, horticultural and livestock systems. The information will be used as input in a biophysical hydrological model of the Indus basin (e.g. SWAT) to estimate/visualize the N flows. This is particularly relevant as a large proportion of agriculture in the basin is irrigated. The information and model will be used as a tool to identify and highlight target areas where various interventions can be made to better manage fertilizer and nutrients for improved ecosystem services including soil fertility, agricultural production and water quality. The work will be carried out in close collaboration with the local NARES and ARIs and it is through these agencies that N management strategies will be developed and disseminated as well as communicated to policy and decision makers.