Environmental Sustainability Assessment of Two Crop Ecosystems with Ecological Footprint Analysis Approach (Case Study: Dez Catchment)

Wheat and maize are important and strategic crops in Iran. These crops are widely grown in the Dez catchment area. Therefore, due to climate change, recent droughts, water bankruptcy in the country, low water consumption efficiency in agriculture, and the excessive consumption of input which pose a serious threat to agriculture and food security, it is necessary to achieve a correct understanding of the sustainable production of crops in the region. Improper use of chemical fertilizers, pesticides, fossil fuels, machinery causes irreversible damage to the environment. To reduce these adverse environmental effects of methods the idea of sustainable agriculture and the transformation of agriculture from high-input to low-input consumption is very important. The footprint index determines the amount of pressure on nature caused by man or other man-made systems. The carbon uptake criterion is used as a basis for assessing the ecological footprint. Ecological footprint estimates the amount of productive land needed to compensate for the environmental impacts of a particular activity by calculating resource consumption and carbon dioxide production. According to studies, each hectare of land can absorb 1.8 tons of carbon. The carbon uptake criterion is used as a basis for assessing the ecological footprint.

The method of the present study has a practical approach because it is in line with achieving sustainable agricultural development. This research was carried out in the cropping year of 2019-2020 at the Dez catchment. To determine the environmental sustainability of agriculture we used the modified ecological footprint method presented by Kissinger and Gottlieb (2012) and Guzman et al (2013). In this study, the ecological footprint was determined based on a place-oriented approach by obtaining energy consumption of the inputs, and the amount of crop and land energy. All the variables were collected in the form of a questionnaire and through interviews with 400 farmers of wheat and maize in the study area. Equivalent factors were also selected from similar studies. Independent samples t-test was performed between the two crops to determine whether there are differences in evaluation of EF.

The results of evaluating the ecological footprint method of wheat and maize cultivation in the study area at the level of one hectare were 3.50 and 4.66 global hectares, respectively. The results of the ecological footprint assessment for wheat and maize showed that both cropping systems are in an unsustainable state in terms of the environment. These systems produce 1.7 tons and 2.86 tons of excess carbon to produce wheat and maize, respectively which are more than the ecological capacity of one hectare to absorb environmental pollution. For both wheat and maize crops, nitrate fertilizer with 40.85% and 49.36%, diesel fuel with 18.57% and 17.60%, and water consumption with 14.57% and 16.31%, respectively, had the greatest impact on environmental instability in the study area. Mean comparison of the ecological footprint between the two crops showed that there was no significant difference between wheat and maize. The high ecological footprint of traditional agriculture was consistent with previous studies (Naderi Mahdei et al, 2015; Kissinger and Gottlieb, 2012; Bevec et al, 2011). Also, the important role of nitrate fertilizer and fossil fuels in increasing environmental hazards and ecological unsustainability was consistent with Fallahpour et al, (2012). It should be noted that No study was found to contradict the findings of the current study.

Both wheat and maize cropping systems were not environmentally sustainable and the total consumption inputs for both crops; chemical fertilizers, especially nitrate fertilizer and then diesel fuel have had the greatest impact on environmental instability in the study area. As a final result, the ecosystem of irrigated wheat production is more desirable than grain maize in terms of environmental sustainability, therefore, the production of both crops, especially maize, must be done with the highest accuracy and consider environmental considerations in the region.