Impacts of dairy farming systems on water quantity and quality in Brazil, Ethiopia, Nepal, New Zealand and the USA^*

Abstract

This study examined the performance of dairy farming systems in Brazil, Ethiopia, Nepal, New Zealand and the USA, based on existing databases of the Food and Agriculture Organization of the United Nations, and country-specific data sources. There are primarily three types of dairy farming, with pasturebased open grazing being the dominant one in Brazil and New Zealand. In the USA, stall-feeding is more popular, while mixed dairy farming is traditionally adopted in Ethiopia and Nepal. Compared to the mixed and pasture-based systems, the stall-feeding system puts more pressure on water quantity, as the water requirement to produce a given amount of concentrated feed required for a stall-feeding system is higher than to produce an equivalent amount of grass, crop residue and fodder required for pasture-based and mixed systems. Nitrate leaching, and subsequent contamination of water resources, is the biggest environmental problem, with the high-intensity stall-feeding in USA, followed by the pasture-based system in New Zealand, being the most challenging in terms of managing nutrient losses. Irrigation networks with sufficient and appropriate flow control structures, and irrigation scheduling that incorporates plant-available water, soil moisture and plant growth stages, are prerequisites for conversion of low-productive agricultural land into highproductive dairy farming.