Wheat is the most widely cultivated crop in Southern Italy, mainly under rainfed conditions. Planning suitable irrigation and fertilization strategies is a crucial issue for stabilizing production and thereby enhancing socio-economic development of farm communities. However, imposed irrigation and agronomic practices can generate more pressure on water resources and environmental burdens due to additional energy and fertilizers requirements. Life cycle assessment (LCA) has been recognised as a valuable tool for assessing the environmental impacts of agricultural production and has been applied widely to winter wheat production. While LCA consider only the environmental aspects, the concept of eco-efficiency (EE) has been used as an instrument to analyze farm sustainability, i.e. to relate economic value of an activity and its impact on environment. The aim of this study is to analyze the eco-efficiency of wheat cultivation under rainfed and irrigation conditions in Apulia Region, Southern Italy. The study applies a novel approach (EcoWater, 2014) based on a combination of the Life Cycle Assessment (LCA) following ISO principles and the assessment of Life Cycle Costing (LCC). LCA followed a problem oriented approach using CML-IA baseline 2000 impact assessment method. The system boundaries were defined following the "cradle to grave" approach (i.e. from the extraction of primary resources to final use in the field). The environmental burdens covered induced emissions through the production and use of fossil fuel, production and use of fertilizers and electricity usage for irrigation. A distinction was made between impacts coming from direct use of resources on-field (foreground) and resource production processes (background). Fertilizer (direct/indirect N2O and other substances) and diesel on-field emission were estimated and converted using the IPCC Guidelines. Emission values for production of fertilizers and power inputs (i.e diesel and electricity) were retrieved from LCA databases. Total Value Added (TVA) to the product due to water use estimated as a difference between of total economic value generated from water use (substracting non-water expenses from total value of products) and total financial cost related to water supply was employed to analyse the economic performance. Eco-Efficiency Indicators (EEI) were defined as ratios of the economic performance (total value added, TVA) to the environmental performance of the system (environmental impacts). The respective assessment was performed using Systemic Environmental Analysis Tool (SEAT) and the Economic Value Analysis Tool (EVAT) modeling tools. The analysis encompassed cause-effect relations and shows whether EE improves or declines and in which respect. Obtained results showed that optimal production with water application of 2000 m3/ha and associated agronomic practices generates on average about 55% additional emissions versus rainfed condition, with the highest impact for terrestrial eco-toxicity by 84% and the lowest for eutrophication potential by 26%. Given the additional fertilizer use for anticipating higher yield rates an increase of 11%, 16%, 17%, and 21% was estimated for climate change, eutrophication, acidification and respiratory inorganics impact categories, respectively. Impacts slightly increase with fertilization levels for human toxicity, terrestrial eco-toxicity and mineral depletion environmental categories. The economic analysis indicated that total value added of the system greatly depends upon the yields achieved, i.e. upon the level of water use. Total Value Added (TVA) to the product due to water use with a fixed market price of 250 EUR/tn was estimated 509 EUR (145.4 EUR/tn) and 929 EUR (143 EUR/tn) for rainfed and irrigated conditions, respectively. In a EE assessment an economically less advantageous product/strategy can compensate for this disadvantage with a better ecological performance, and vice versa. Estimated EEI showed that the additional agricultural production achieved under full potential irrigation compensates for additional emissions for almost all categories, except for human toxicity, terrestrial eco-toxicity and mineral depletion environmental categories. Analysis demonstrate the importance of the adopted irrigation practices and show that a product under limited (deficit) irrigation might have a greater EE than a product under full irrigation. The latter becomes less eco-efficient because the environmental impacts linearly increase with the increased water supply and corresponding agronomic practices and they cannot be always compensated by any higher total value added (for example in the case of human toxicity). Nonetheless, the results confirms that under current market conditions, irrigation remains a relatively profitable activity, as well as providing greater stability of income. If however, prices for water increase, seasonal precipitation is greater than 300 mm and market price is lower then 250 EUR per hectare, then the relative profitability of irrigation may decrease.
ECO-EFFICIENCY OF WHEAT CULTIVATION UNDER RAINFED AND IRRIGATED CONDITIONS
Vito Cantore
2015
Abstract
Wheat is the most widely cultivated crop in Southern Italy, mainly under rainfed conditions. Planning suitable irrigation and fertilization strategies is a crucial issue for stabilizing production and thereby enhancing socio-economic development of farm communities. However, imposed irrigation and agronomic practices can generate more pressure on water resources and environmental burdens due to additional energy and fertilizers requirements. Life cycle assessment (LCA) has been recognised as a valuable tool for assessing the environmental impacts of agricultural production and has been applied widely to winter wheat production. While LCA consider only the environmental aspects, the concept of eco-efficiency (EE) has been used as an instrument to analyze farm sustainability, i.e. to relate economic value of an activity and its impact on environment. The aim of this study is to analyze the eco-efficiency of wheat cultivation under rainfed and irrigation conditions in Apulia Region, Southern Italy. The study applies a novel approach (EcoWater, 2014) based on a combination of the Life Cycle Assessment (LCA) following ISO principles and the assessment of Life Cycle Costing (LCC). LCA followed a problem oriented approach using CML-IA baseline 2000 impact assessment method. The system boundaries were defined following the "cradle to grave" approach (i.e. from the extraction of primary resources to final use in the field). The environmental burdens covered induced emissions through the production and use of fossil fuel, production and use of fertilizers and electricity usage for irrigation. A distinction was made between impacts coming from direct use of resources on-field (foreground) and resource production processes (background). Fertilizer (direct/indirect N2O and other substances) and diesel on-field emission were estimated and converted using the IPCC Guidelines. Emission values for production of fertilizers and power inputs (i.e diesel and electricity) were retrieved from LCA databases. Total Value Added (TVA) to the product due to water use estimated as a difference between of total economic value generated from water use (substracting non-water expenses from total value of products) and total financial cost related to water supply was employed to analyse the economic performance. Eco-Efficiency Indicators (EEI) were defined as ratios of the economic performance (total value added, TVA) to the environmental performance of the system (environmental impacts). The respective assessment was performed using Systemic Environmental Analysis Tool (SEAT) and the Economic Value Analysis Tool (EVAT) modeling tools. The analysis encompassed cause-effect relations and shows whether EE improves or declines and in which respect. Obtained results showed that optimal production with water application of 2000 m3/ha and associated agronomic practices generates on average about 55% additional emissions versus rainfed condition, with the highest impact for terrestrial eco-toxicity by 84% and the lowest for eutrophication potential by 26%. Given the additional fertilizer use for anticipating higher yield rates an increase of 11%, 16%, 17%, and 21% was estimated for climate change, eutrophication, acidification and respiratory inorganics impact categories, respectively. Impacts slightly increase with fertilization levels for human toxicity, terrestrial eco-toxicity and mineral depletion environmental categories. The economic analysis indicated that total value added of the system greatly depends upon the yields achieved, i.e. upon the level of water use. Total Value Added (TVA) to the product due to water use with a fixed market price of 250 EUR/tn was estimated 509 EUR (145.4 EUR/tn) and 929 EUR (143 EUR/tn) for rainfed and irrigated conditions, respectively. In a EE assessment an economically less advantageous product/strategy can compensate for this disadvantage with a better ecological performance, and vice versa. Estimated EEI showed that the additional agricultural production achieved under full potential irrigation compensates for additional emissions for almost all categories, except for human toxicity, terrestrial eco-toxicity and mineral depletion environmental categories. Analysis demonstrate the importance of the adopted irrigation practices and show that a product under limited (deficit) irrigation might have a greater EE than a product under full irrigation. The latter becomes less eco-efficient because the environmental impacts linearly increase with the increased water supply and corresponding agronomic practices and they cannot be always compensated by any higher total value added (for example in the case of human toxicity). Nonetheless, the results confirms that under current market conditions, irrigation remains a relatively profitable activity, as well as providing greater stability of income. If however, prices for water increase, seasonal precipitation is greater than 300 mm and market price is lower then 250 EUR per hectare, then the relative profitability of irrigation may decrease.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
