Ecological footprint of beetroot and cabbage in different production systems

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1 ORIGINAL SCIENTIFIC PAPER Ecological footprint of beetroot and cabbage in different production systems Matjaţ Turinek 1, Maja Turinek 1, Silva Grobelnik Mlakar 1, Franc Bavec 1, Martina Bavec 1 1 Faculty of Agriculture and Life Sciences, University of Maribor, Pivola 10, 2311 Hoĉe, Slovenia (martina.bavec@uni-mb.si) Abstract Intensive industrial farming is, as a large polluter, evermore subjected to public pressure, as more sustainable ways of farming are demanded. However, there are no wholesome indicators to evaluate the sustainability of a production system (PS). Our goal was to extend and use a tool - the Sustainable Process Index (SPI) - for evaluating the sustainability of cabbage (Brassica oleracea L. convar. capitata) and beetroot (Beta vulgaris L.) production in 4 PS (conventional(con), integrated(int), organic(org) and biodynamic(bd)) and a control treatment. Results show great differences between the ecological footprint of PS (control<org<bd<int<con), where critical points in need of improvement during the production process become visible (fertilisation and machinery use). The calculated index of ecological efficiency reinforced the trend of the SPI results. SPI is a good and accessable tool for producers and policy makers. Key words: ecological footprint, production systems, vegetable production, Sustainable Process Index - SPI Introduction The world commission for environment and development (the Brundtlandt commission) coined the definition of sustainable development in the year 1987 it is development, which satisfies the needs of current generations without compromising the needs of future generations (WCED, 1987). But it is difficult to determine or use sustainable development in everyday practice. And it is even harder to measure it. Here indicators can be of help at defining and communicating questions on sustainable development and can be used to predict and follow results of political decisions. According to van der Werf et al. (2007) indicators and/or tools for evaluating sustainable development have to be chosen very carefully; regarding the method, which best suits the needs, set goals and expected results. Ecological footprint (EF) (Wackernagel and Rees, 1995) tries to summarize the biologically productive area, which is needed to produce yearly flows of materials spent by the population of a certain region (city, state, world) with all accompanying waste in the form of emissions (especially CO 2 ) and the area needed for building infrastructure. This is compared to the area available to a certain population or individual, called the biocapacity (Haberl et al., 2001). Data for the EF is usually excerpted from statistical databases; in the case of agriculture from yearly statistics of individual countries. The drawback of such data lies in the inaccuracy of the attained footprint for smaller units e.g. farm level. LCA (life cycle assessment) is a tool based on actual/real data, it assesses the environmental burden caused by a product, the production process or activity (Curran, 2008). It takes into account the technological processes of all activities, basic materials and transportation into and from the production unit. In the second step sources used for each single input are evaluated by adding the environmental impact, including the resulting emissions and waste. The result can be interpreted on a per unit of product basis (kg) or 147

2 Agroecology and Organic Agriculture equivalent area (ha), where areas used outside of the production unit are included (van der Werf et al., 2007). The only drawback of this tool is the limited comparability of the gained data on a world or state level. Consequently LCA needs to be joined with other indicators or tools. Research in the area of the EF or the LCA in agriculture is still developing. Furthermore, to our knowledge up-to-date there has been no scientific research published on comparing production of vegetables in different production systems using a joint framework of the EF and LCA called the Sustainable process index - SPI (Narodoslawsky and Krotscheck, 1995; Krotscheck and Narodoslawsky, 1996; Sandholzer and Narodoslawsky, 2007). With a long-term field trial we tried to fill this void and bring some more clarity to the discussion of sustainability of various production systems. In this sense experimental data from a long-term field trial is used in this paper, therefore results reflect conditions in reallife situations and farming systems. Material and methods Long-term field trial The long-term field trial is located at the experimental site of the University Agricultural Centre, University of Maribor. The mean air temperature of the area in the growing period (May-September) was 18,6 C, total rainfall in the same period amounted to 436 mm. Thirty 7m 10m experimental field plots were established in autumn 2007 on a dystric cambisol (deep) (average ph value 5.5 (0.1 KCl solution), soil soluble P at g/kg -1 and soil soluble K at g/kg -1 in ploughing soil layer), within two different five-course crop rotation designs. In one rotation there are typical crops for this region (two years of red-clover grass, wheat, white cabbage, oil pumpkins), the other one is an alternative crop rotation (two years of red-clover grass mixture, spelt, red beet, false flax/garden poppy). Four production systems + control plots were arranged in a randomised complete block split-plot design with four replicates. The farming systems differed mostly in plant protection and fertilization strategies (Turinek, 2009). The farming systems used are defined by the valid legislation and standards conventional (CON) (MKGP, 2008), integrated (INT) (MKGP, 2002; MKGP, 2008; Dţuban, 2009), organic (ORG) (EC, 2007), biodynamic (BD) (EC, 2007; Demeter International, 2009) and control (MKGP, 2008) farming system, where no fertilization/plant protection was used. SPIonExcel tool In order to include easily applicable tools that give an overall picture of environmental impacts of products and processes and on top of that offer insights into the steps of a life cycle that exert the largest environmental pressures, Life cycle assessment with the Sustainable Process Index (SPI), a member of the EF family, is well suited for this task (Sandholzer and Narodoslawsky, 2007). We will not go into details of this method, as they are described in several research papers (Krotscheck and Narodoslawsky, 1996; Sandholzer and Narodoslawsky, 2007). However, SPIonExcel was developed to bring the underlying methodology into an easy applicable form. It calculates the EF of a process and SPI of a product or service through the input that characterizes the process given by an eco-inventory. The eco-inventories used for the calculation of the overall footprint contain engineering mass and energy flows of processes in terms of input and output flows (Sandholzer and Narodoslawsky, 2007). From the attained footprint an additional ecological efficiency of production systems was calculated using the following equation: ecological footprint Ecological efficiency of production = yield (1) th Croatian & 5 th International Symposium on Agriculture

3 The SPI as calculated by Eq. (1) gives an indication of the cost in terms of ecological sustainability of a given product or service (Sandholzer and Narodoslawsky, 2007). The number indicates what fraction of the overall ecological budget of a production system is used to provide this good or service - in our case 1 kg of beetroot or cabbage dry matter (DM) yield. Lower values indicate better environmental performance of production systems. Data used All work done on the trial in 2008 was carefully monitored and recorded. Data collected from the field trial were transformed into tasks done in a system in one year and the time needed for those tasks (e.g. ploughing, seeding, harrowing, spraying, etc.). Because of the nature of the trial, where not all operations could be done by machines (e.g. spraying), reallife operational times were taken from the University Agricultural Centre Farm, where the experiment took place. The footprint was determined for 1 ha of area. Statistical analysis Data for the ecological efficiency of production were analysed by one-way ANOVA with production system as a factor using Statgraphics Centurion (Version XV, StatPoint Technologies, Inc., Warrenton, VA) and were followed by means comparisons after Duncan (Hoshmand, 2006). Values given within the paper are means ± standard error (SE). Results and discussion When looking at the results of the EF of production systems for cabbage and beetroot, a high proportion of the final footprint with CON and INT systems derives from the use of mineral fertilizers and pesticides (Table 2). However, ORG and BD systems have higher footprints in the field of machinery use impacts, mainly because of manure spreading, harrowing and the use of BD preparations with the BD system. The surprising fact is, that also control plots for cabbage and beetroot production leave an EF of ,0 m 2 and ,4 m 2, respectively. This means that only by using current standard machinery to till the soil and produce crops, we already leave a great environmental impact and consume times more land than is needed to plant the crops on. In this sense there is great need for improvement in the current agricultural practice and the way we understand, till and work the soil. Furthermore, alternative fuels (e.g. plant oils) and more efficient machinery are a must in order to minimize the impact of agricultural production on the environment. Some good examples of prospective development in this area already exist. However, when the total EF area of CON cabbage and beetroot production, which amounts to ,4 m 2 and ,2 m2, respectively, is visualized, it takes some effort to perceive and realize the vast impact this industrial way of farming really has on the environment and ecosystems. The INT system does not perform any better, although it is publicised and advertised as nature friendlier and as one of the sustainable agricultural systems (MKGP 2002). Results of the ecological efficiency of production give an even more insightful picture, as yields are taken into the equation (Table 3). When compared to the CON system, significantly higher efficiency (4.6, 5.7 and 4.2 times higher) was attained with the use of the control, ORG and BD farming systems for cabbage production, respectively. Similar values can be observed for beetroot production. One has to keep in mind, however, that these are the results for the first year of vegetable production after grass-clover, thus values and ratios will probably change in the next 2-3 years of the trial, where control plots are 149

4 Agroecology and Organic Agriculture expected to produce lower yields. The ORG and BD systems are expected to have significantly higher ecological efficiencies of production compared to the other systems. Table 2 The EF for 1 ha of cabbage and beetroot production in Production system control CON INT ORG BD Cabbage: Production area (m 2 ) Machinery (m 2 ) Fertilizers and pesticides (m 2 ) Seed (m 2 ) Total footprint (m 2 ) Index (%) Beetroot: Production area (m 2 ) Machinery (m 2 ) Fertilizers and pesticides (m 2 ) Seed (m 2 ) Total footprint (m 2 ) Index (%) Table 3 Ecological efficiency (EE) of cabbage and beetroot production for 2008 expressed in m 2 of impact for 1 kg of produced DM yield. Means ± SE, n=3. Different letters indicate statistically significant differences at P 0.05 (Duncan test). Production system control CON INT ORG BD Cabbage, *: EE (m 2 kg -1 ) 83,2±26,6 b 384,6±37,6 a 321,2±69,7 a 67,7±11,5 b 91,5±23,2 b Beetroot, *: EE (m 2 kg -1 ) 118,4±16,9 c 1.497,8±174,4 a 668,2±93,2 b 167,9±19,8 c 186,2±29,0 c n.b. Lower values indicate better ecological efficiency. Conclusion To discontinue the use of mineral fertilizers and pesticides would obviously improve the EF and ecological efficiency of the nowadays prevalent CON and INT farming systems. In addition, the efficient use of machinery and inventing new forms of working the soil will be of crucial importance in the future in order to make all of our current farming systems more sustainable. Acknowledgement The results presented in this paper are an output of the research project J4-9532: The quality of food dependent on the agricultural production method, funded by the Ministry of Higher Education, Science and Technology of Slovenia. References Curran, M. (2008). Life-Cycle Assessment. In: Encyclopedia of Ecology. Oxford: Academic Press, pp Demeter International (2009). Production Standards for the use of Demeter, Biodynamic and related trademarks. Available at: /st_production_e09.pdf [Accessed February 2, 2009] th Croatian & 5 th International Symposium on Agriculture

5 Dţuban T. (2009). Tehnološka navodila za integrirano pridelavo zelenjave: leto pages. Ljubljana, Ministrstvo za kmetijstvo, gozdarstvo in prehrano. EC (2007). Council Regulation (EC) No 834/2007 of 28 June 2007 on organic production and labelling of organic products and repealing Regulation (EEC) No 2092/91. Available at: 189:0001:0023:EN:PDF [Accessed February 2, 2009]. Haberl H., Erb K.H., Krausmann F. (2001). How to calculate and interpret ecological footprints for long periods of time: the case of Austria Ecological Economics, 38: Hoshmand A.R. (2006). Design of Experiments for Agriculture and the Natural Sciences Second Edition 2nd ed.. Chapman & Hall/CRC. Krotscheck C., Narodoslawsky M. (1996). The Sustainable Process Index a new dimension in ecological evaluation. Ecological Engineering, 6: MKGP (2002). Pravilnik o integrirani pridelavi zelenjave. Available at: [Accessed September 20, 2009]. MKGP (2008). Zakon o kmetijstvu. Available at: objava.jsp?urlid=200845&stevilka=1978 [Accessed September 20, 2009]. Narodoslawsky M., Krotscheck C. (1995). The sustainable process index (SPI): evaluating processes according to environmental compatibility. Journal of Hazardous Materials, 41: Sandholzer D., Narodoslawsky M. (2007). SPIonExcel-Fast and easy calculation of the Sustainable Process Index via computer. Resources, Conservation and Recycling, 50: Turinek M. (2009) Ecological footprint of some field crops and vegetables in different production systems. Maribor, Faculty of Agriculture and Life Sciences, Dissertation thesis. van der Werf H.M., Tzilivakis J., Lewis K., Basset-Mens C. (2007). Environmental impacts of farm scenarios according to five assessment methods. Agriculture, Ecosystems & Environment, 118: Wackernagel M., Rees W. (1995). Our Ecological Footprint: Reducing Human Impact on the Earth. 160 pages. Canada, New Society Publishers. WCED, (1987). Our Common Future. 400 pages. US: Oxford Paperbacks. 151