Life cycle assessment of milk produced in two smallholder dairy systems in the highlands and the coast of Peru
Introduction
Milk production is associated with environmental impacts such as acidification and eutrophication of soil and water bodies or global warming caused by the emission of greenhouse gases (De Vries and Boer, 2010). Interest in the development of methods in order to better understand such possible environmental impacts associated with the production and consumption of products has increased recently (ISO, 2006). Life cycle assessment (LCA) is a method developed in order to assess the environmental aspects and potential environmental impacts throughout a product’s life cycle and provides a widespread insight into the environmental burdens associated with a product or a human activity (ISO, 2006). Some studies have already applied LCA on typical regional (Hospido et al., 2003) or national (Chen et al., 2005, Basset-Mens et al., 2009) milk production systems or focussed on comparisons of conventional with organic production systems (Thomassen et al., 2008, Boer, 2003) or different production scenarios (Basset-Mens et al., 2009, Casey and Holden, 2005). No LCA on milk production has so far been elaborated for a tropical region.
Milk production in Peru has grown quickly during the last 15 years (up to 60% between 1990 and 2003; (FAOSTAT, 2008)) and the sale of milk is an important source of income especially for smallholder farmers. Most of the studies mentioned above have identified the production and use of feed to be the main contributor to the total environmental impact of milk. Furthermore the production level significantly influences the environmental performance if the impact is expressed per unit of milk produced (Thomassen et al., 2009). Dairy feed and milk production levels vary considerably between the smallholder milk production systems in the Peruvian highlands and the coastal region. In the Peruvian highlands, smallholder milk production is based on local Criollo cattle on permanent pastures supplemented with ryegrass-clover (Bartl et al., 2009) whereas dairy cows at the coast are Holstein-Friesian breed and are fed a diet consisting of fodder maize and concentrate (Gómez, 2008).
The hypothesis tested in this study was that typical Peruvian smallholder dairy systems in the Andean highlands and at the coast have different potential environmental impacts mainly due to different feeding systems and milk production levels.
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Material and methods
In this project we applied an attributional LCA (Rebitzer et al., 2004), which analyses the resource inputs and the emissions within a defined system attributed to the production of 1 kg energy corrected milk (ECM). According to ISO 14044 (ISO, 2006) the study includes a goal and scope definition, inventory analysis, impact assessment and interpretation of results.
Life cycle inventory for 1 kg ECM
Permanent pastures contribute to 84.5% of all land used in the highlands and 96.7% of the water is consumed for the irrigation of forages. The land use for milk production at the coast is distributed between production of forages (58.3% of total land used) and concentrate ingredients (41.7%). Most of the water (77.8%) and energy (76.9%) used at the coast are spent for the production of the concentrate ingredients (Table 5).
Ammonia, N2O and CH4 emissions to the air are higher by 144, 70 and 477%
Method and data availability
When interpreting the LCA results it has to be considered that due to the lack of real farm data regarding emissions, the environmental impact calculated with an LCA differs from the actual environmental impact (Thomassen et al., 2008). Especially when comparing different systems producing the same product the accuracy of data has to be high and a large amount of data has to be available (Basset-Mens and Werf, 2005). Thanks to detailed data collection for other purposes sufficient accurate on
Conclusions
The environmental burden of 1 kg energy corrected milk (ECM) produced in two typical smallholder Peruvian production systems in the highlands and at the coast were shown to differ considerably with impacts being higher by 333, 87 and 219% in the highland than in the coastal system for global warming potential, acidification and eutrophication, respectively. The highland system was characterized by a high land occupation and a high emission of methane per kg ECM. On the other hand, emissions per
Acknowledgements
We gratefully acknowledge the participation of the farmers in Chalhuas, Sallahuachac and San Felipe and of the administration personnel of the Asociación de Ganaderos de la Irrigación San Felipe. The provision of data by Fabia Parola is very much appreciated. This work was supported by ETH Research Grant CH1-03 08-3.
References (81)
- et al.
Applications of reduced tillage in hills of central Nepal
Soil and Tillage Research
(2006) - et al.
Economic evaluation of the current and alternative dual-purpose cattle systems for smallholder farms in the central Peruvian highlands
Agricultural Systems
(2009) - et al.
Effect of diet type on performance and metabolic traits of Peruvian local and introduced cow types kept at 200 and 3,600 m of altitude
Livestock Science
(2009) - et al.
Scenario-based environmental assessment of farming systems: the case of pig production in France
Agriculture Ecosystems and Environment
(2005) - et al.
Eco-efficiency of intensification scenarios for milk production in New Zealand
Ecological Economics
(2009) - et al.
Analysis of greenhouse gas emissions from the average Irish milk production system
Agricultural Systems
(2005) - et al.
The water footprint of cotton consumption: an assessment of the impact of worldwide consumption of cotton products on the water resources in the cotton producing countries
Ecological Economics
(2006) - et al.
IJM: comparing environmental impacts for livestock products: a review of life cycle assessments
Livestock Science
(2010) - et al.
Systems dynamics and the spatial distribution of methane emissions from African domestic ruminants to 2030
Agriculture Ecosystems and Environment
(2008) - et al.
Simplified life cycle assessment of Galician milk production
International Dairy Journal
(2003)