Silage corn production in conventional and conservation tillage systems. Part I: Sustainability analysis using combination of GIS/AHP and multi-fuzzy modeling

This study was carried out to assess the sustainability of silage corn production in Fars province, Southwest Iran. Two tillage systems (conventional (T1) and reduced (T2)) and farm sizes (A1 ≤ 6 ha and A2 > 6 ha) were considered. The suitability of land for silage corn cultivation regarding soil and climatic factors was evaluated employing GIS/AHP. This is the first attempt in which GIS/AHP has been used to determine homogenous regions and consequent farmers’ selection from the regions. The sustainability of silage corn production was ascertained using multi-fuzzy modeling. Eight fuzzy models were designed including four sustainability aspects; i.e. agronomic, mechanization, social and economic. Land suitability analysis revealed that the total area classified as three suitability classes; i.e. “most suitable” (R1), “moderately suitable” (R2) and “marginally suitable” (R3). The lowest sustainability indices belonged to agronomic factors with “very low” to “medium” domains of sustainability. The final fuzzy model revealed that silage corn sustainability was 39.81 (“low” and “medium” with membership grades 0.509 and 0.491, respectively), 39.24 (“low” and “medium” with membership grades 0.538 and 0.462, respectively) and 35.36 (“low” and “medium” with membership grades 0.732 and 0.268, respectively) in R1, R2 and R3, respectively. It was found that using less water, fertilizers and chemical pesticides would result in noticeable enhancement in sustainability indices particularly agronomic. Since almost all the indices were higher in larger farms and reduced tillage system, it was suggested that the farmers should move toward using T2 in A2. Furthermore, it was recommended that more study is needed to find a substitute crop for R3 since it was classified as “marginally suitable” for silage corn.