A robust assessment of water used in agriculture, including livestock production systems and supply chains, is critical to inform diversification and the development of productivity and sustainable food production systems. This paper presents a detailed analysis of water used and consumed in nine dairy milk processing plants spread across Punjab, India’s leading dairy milk-producing state. Over the five years (2015–2019), the direct water use (DWU) was quantified at 3.31 L of groundwater per kg of milk processed. Only about 26% of the direct water used was consumed, including evaporative losses in various milk processing operations, while the remaining 74% was returned as effluent discharges. The average total water footprint (TWF), accounting for both direct and indirect water consumption, was quantified at 9.0 L of water per kg of milk processed. The majority share (~89%) of the total water footprint was contributed by the indirect water footprint associated with the consumption of electricity (energy) in dairy milk processing activities. The plant’s milk processing capacity and processing products mix also affected significant seasonal and annual variations in the direct and indirect water footprints of dairy milk processing. The analysis also found an inverse relationship between the average total water footprint and the average monthly amount of milk processed in the study plants. Therefore, efforts to reduce the indirect water footprint (associated with energy consumption), the treatment and recycling of effluent discharges, and the optimization of milk processing capacity, the dairy processing product mix, and the locations of dairy processing plants are expected to help reduce the water footprint of dairy processing in the state.

Context: Dairy farming will be increasingly scrutinised for its environmental impacts, in particular for its impacts on freshwater quality in New Zealand and elsewhere. Management and mitigation of high nitrate losses is one of the greatest water-quality challenges facing dairy farming in New Zealand and other countries. Management of critical flow pathways and nitrate-attenuation capacity could offer potential solutions to this problem and help maintain dairy-farming productivity, while reducing its water-quality impacts. Aims: The present paper reviewed the key water-quality issues faced by dairy farming and assessed potential of emerging edge-of-paddock technologies, and catchment-scale nutrient-attenuation practices, to reduce nitrate losses from dairy farming to receiving water bodies. Methods: We developed a conceptual catchment-scale modelling analysis assessing potential natural and built attenuation of nitrate losses from dairy farming in the Tararua and Rangitikei catchments (located in the lower part of the North Island, New Zealand). Key results: This exploratory analysis suggests that a reduction of greater than 25% in the river nitrate loads from dairy-farming areas could potentially be achieved by spatially aligning dairy land with areas of high subsurface nitrate-attenuation capacity, and by managing critical flow pathways using innovative edge-of-field technologies such as controlled drainage, drainage-water harvesting for supplemental irrigation, woodchip bioreactors, and constructed wetlands in the study catchments. Conclusions: The research findings highlighted the potential to better understand, map and effectively utilise existing natural and new built-in nitrate-attenuation capacity to significantly reduce water-quality impacts from dairy farming across environmentally sensitive agricultural catchments. This knowledge and tools could help farmers close the gap between what can be achieved with current, in-field mitigation practises and the nitrogen-loss allocation imposed by regulatory authorities. Implications: However, the research findings presented here are based on a coarse-scale, conceptual modelling analysis, and therefore further research is recommended to develop tools and practices to better understand, map and effectively utilise existing natural and new built-in nitrogen attenuation capacity at farm-scale to achieve productive and environmentally friendly pastoral dairy farming across agricultural landscapes.