Increases in productivity gained by agricultural intensification often have an ecological cost, but this is typically paid for in a different time or location. For example, depleting underground freshwater aquifers or exhausting energy reserves means ‘borrowing’ these resources from future generations. Another example is erosion of hill country, which adds sediment to rivers and contributes to flooding of lowlands.
The expansionist phase of agricultural production in New Zealand came to an end in the mid-20th century. Since then, there has been a drive towards agricultural intensification – to produce more milk, lambs, wool, meat or crops from the same land area. This has accelerated since the 1970s, due to increasingly competitive overseas markets. Farmers have increased productivity by using new technologies and using more water and fertiliser.
In 2004, after an extensive inquiry, the Parliamentary Commissioner for the Environment issued a report, Growing for good. It found that intensified farming was causing many pressing environmental problems, including declining water quality in many areas. According to the report, the growth in demand for irrigation water appeared to be unsustainable in some regions.