Estudio micrográfico de las placas mecanizadas

There is a common assumption while assessing productivity that the value of inputs into production are assumed to be equal to their total costs (York, 2011). This theory assumes that free inputs, such as many natural resources, do not add measurable value to farmers. Although water in New Zealand is free, it obviously has substantial benefits for many farmers. There are costs associated with accessing water, but the water itself is not priced. When valuing natural resources, selecting a proxy price for a free good is contentious. York (2011) suggests the good’s production cost or using an existing market price from within the country are the most available and least controversial options. However, production costs generally value the cost to provide water and not the value of water itself so may significantly under- estimate the value of water. For example, Lynch & Weber (1992) found the public value of water resources was much higher than the value of water to farmers. They found the value of in-stream flows of the Ashburton River to Canterbury residents averaged between $2.47 and $5.15 million; however, the value of water to farmers in the Ashburton catchment was only $0.62 million.

The economic value of groundwater resources to users in the Waimea Plains is estimated at $250 million and represents around 1% of New Zealand’s total consumptive water allocation and 3% of New Zealand’s groundwater allocation (White et al., 2001). This equates to $38 to $42 million for irrigators on the Waimea Plains (marginal value of $240 to $300/m3). Applying the economic value of Waimea Plain’s groundwater to New Zealand’s total consumptive water allocation would attain an economic value of around $24 to $25 billion (White et al., 2001). Additionally, if non-consumptive uses were included the value would increase significantly (White et al., 2001).

Irrigation in Canterbury – Hurunui

Infrastructure improvement projects have been proposed for the Hurunui Catchment in North Canterbury to increase water availability for irrigation. The current area of irrigated land in the catchment is about 22,300 ha, of a total catchment area of 246,600 ha. Over 99% of the base irrigation occurs in the plains area (comprising over 76,000 ha), which has the highest productivity and revenue potential (Daigneault et al., 2011). The plains area produces a high proportion of the catchment’s nutrient loads and GHG emissions and also has the greatest potential to alter its environmental outputs through changes in farm inputs and land use (Samarasinghe et al., 2011).

Valuation of Impacts 149 Total catchment income before irrigation development was estimated at $224.4 million

(Daigneault et al., 2011). There is a large difference in farm incomes for farms with and without irrigation and there is little additional water available in the region to be allocated (Daigneault et al., 2011). Increasing water availability by as much as 86% will only increase total catchment income by 1.7% after additional capital and operation costs from the project are taken into account (Daigneault et al., 2011). Increased production will also increase environmental outputs such as N and P, as well as CO2 emissions from additional farm operations and energy used for irrigation (Daigneault et al., 2011). Additionally, costs to other sectors of the local economy that are reliant on good water quality could increase (Daigneault et al., 2011); however, these have not been accounted for in productivity models.

Furthermore, it is estimated that less than 4,000 of the nearly 20,000 ha of newly irrigated water available would be used on a yearly basis. This is because most land owners would be unable to economically change their land use and inputs while meeting environmental limits; thus catchment income would only increase by 0.3% (Daigneault et al., 2011). The net present value of the Hurunui Water Project was estimated to be in the order of millions to irrigators. In contrast, Kerr (n.d.) argues that the proposed irrigation scheme not only has the potential to impose net costs on society as a whole, but may also be unviable for irrigators. This is because external costs were not included in assessments.

Value of irrigation to dairy

Assessments on an accurate value of water are not possible for the scope of this thesis as water does not have a fixed price. Furthermore, the volume of water that dairy farms use is unknown. A rough estimate of water use could substitute the proportion of irrigated dairy land area as the proportion of water use. However, this is likely to underestimate the volume of water used by dairy if dairy land uses more water per unit of land than other land uses. Of the area equipped with irrigation, dairy covered 49% in 2012. In 2010, 5791.2 million m3 was allocated for irrigation; thus, approximately 2802.9 million m3 per year may be used on dairy land. Water has been priced for the proposed Ruataniwha water storage and irrigation scheme at $0.23/m3 (Hawke's Bay Regional Investment Company, 2014), likely to be used mainly for dairy. Using this water price, estimated water used for dairy nationally is valued at $644.7 million per year. Although this price may not be representative of water prices for agriculture in many catchments, this represents another externality of dairy farming, as farmers largely do not pay for water.

Valuation of Impacts 150

9.2.

Land

Very little cost estimates exist for environmental impacts experienced on land from dairy farming. Those explained here are mainly experienced by farmers and effect dairy productivity, rather than impacts and costs endured by the public.