These indicators have also been used in previous studies as environmental indicators in agriculture

This included their outputs, the market prices for their products,their wage bill and the cost of each input. In the sample, some farms depend exclusively on the family for labour input while others use hired workers.Given that western agriculture is still predominantly characterised by family farms , there is a long established tradition of including family labour in institutional reports and research studies that seek to provide comparable farm incomes . Therefore, we calculate and add the opportunity cost of family work by applying the average hourly cost of external wages in our sample to the number of hours of family work on each farm so as to calculate income before and after wages. Our environmental performance indicators are paddy field GHG emissions and energy consumption, distinguishing between direct and indirect consumption.

The GHG protocol distinguishes three scopes which help identify the information that needs to be collected about the discharged and induced greenhouses gases : Scope 1 deals with emissions released directly by the company. This includes production and service processes owned or controlled by the company as well as the corporate fleet of cars and trucks. The GHG protocol covers only the six GHGs listed in the Kyoto protocol. CFCs and NOx are excluded, it is argued,on political grounds.Scope 2 coverse missions indirectly caused by the generation of purchased electricity. And Scope 3 includes emissions from suppliers of inputs and downstream emissions from distribution, use and end of product. Scope 3 extends this accounting scope to emissions indirectly attributable to the purchase of all kinds of goods and services such as semi-manufactured goods, transportation services, waste disposal services, outsourced activities, etc.

This study considers all three Scopes. Unfortunately,we did not have access to measurements of other environmental externalities of rice production, such as, impact on human health, loss of biodiversity,wildlife and landscape degradation, water filtering or the substitution of natural wet lands . These environmental impacts regrettably lie outside the scope of this paper. The collection and conversion of data were made possible thanks to a joint enterprise involving the authors and the researchers of an EU-funded project for assessing the potential of agriculture to combat climate change . This project seeks to apply a common evaluation system in the four largest agricultural economies of the EU so as to identify suitable farming practices.This has resulted in the development of diagnostic software capable of converting the data collected via surveys into direct  and indirect energy consumption, both expressed in gigajoules  per year. To this end, a questionnaire was first designed to facilitate information collection and to enable aconsistent level of comparison.

With the data, and on the basis of a series of consultations with experts in the field of rice production in the region, the team were able to build the environmental indicators that are used in this study. These data refer to both physical and monetary measurements of farm size, location, annual yields, brand and age of machinery used, litres of fuel consumed, kilograms of seeds planted, amounts of fertilisers, herbicides and pesticides used in the field, characteristics and amounts of water required, and flooding practices during the season. These raw data were then converted into GHG emissions and energy consumption statistics.ISO 14064-1 and the GHG protocol  guidelines were followed to convert the data collected into GHG emissions. Emissions of different GHGs were converted and are expressed in equivalent tons of carbon dioxide per year. The main audience for the results of the study are the farmers included in the sample given that the project studies current practices in order to identify best practices and innovative methods for improving environmental performance. On the conclusion of the study, two meetings were held with the farmers in order to share our results and to suggest practices that help combat climate change.The study sample comprises nine farms. Of the nine farms, eight practise the various techniques of conventional farming and one operates as an organic farm.In total, nine farmers attended a personal interview with the authors of the study.

The selection of farmers was made based on the personal availability to participate and the comparability among farms. In accordance with the ethical agreement governing interviews, the specific identity of the participants cannot be disclosed. Five farms specialise in a variety of rice known by the name of gleva,and four specialise in a variety known as bomba. The varieties of rice produced, the size of the farms and the yield productivity per hectare of the farms included in the sample can be considered representative of rice farms in Spain.All the data collected adhere to the same definitions and were measured applying the same rules. All figures and data correspond to the same year,that of 2011.The inclusion of an organic farm allowed comparisons to be drawn, given that previous research suggests that organic farming tends to have a lower environmental impact .