Evaluation of agrobiodiversity in Ilam Province (during 2004-2016)

Introduction:
Diversification of agriculture is considered an important strategy to overcome the challenges faced by many developing countries due to the opportunities it offers to face heterogeneous production conditions, increase income generation through entry into new markets, and risk management. Conservation of biodiversity is one of the sustainable development concepts in agriculture. Excessive attention to the number of products and the extreme use of off-farm inputs, regardless of other ecological functions of these systems, has led to the reduction of biodiversity at all levels. In this context, a comprehensive plan for monitoring crop diversity and identification of factors influencing diversification is necessary. Accordingly, this study was conducted to evaluate the temporal and spatial changes in the biodiversity of agricultural systems in the Ilam province during 2004 and 2016.
Material and methods:
Data were gathered from statistical yearbooks and reports from the Plan and Budget Organization and Organization of Jihad Agriculture. Stepwise regression analysis was used to identify the factors influencing regional crop diversity fluctuation over time (Also, stepwise recursive regression analysis was used to evaluate the determinant factors in the changes of diversity in agricultural systems.). In order to evaluate the spatial variation of crop diversity in irrigated agroecosystems and its determinants factors, the Shannon-Weiner diversity index was calculated. Based on the assumptions of the study, the influencing factors on the spatial variation of crop diversity were classified into geographical factors, climate and ecological factors, sociocultural factors, economic factors, and management factors. Then, insignificant factors on crop diversity were excluded from the model and finally, the most important determinant on variations between different regions of the province remained in the model.
Results and discussion:
The findings of this study revealed that over the 12-years period, the general trend in the changes of production systems was a decreasing one; so the agricultural systems’ diversity in all counties, except for Ilam and Dehloran, had decreased, of which the highest value of the Shannon-Weiner diversity index was calculated 1.90 in 2016. The main reason for this increase in diversity was the increase in the number of vegetable crops and reducing the area under cultivation of dominant crops (wheat and barley) during the studied period. Furthermore, the main determinant factors of diversity in the agricultural systems of Ilam Province were the number of villages with inhabitants, average annual net income of a rural household, number of cooperatives, number of dusty days, agricultural land areas, number of production units, age of the beneficiary, minority percentage, amount of urea fertilizer, number of family members, and literacy rate, respectively.
Conclusion:
Studying the critical points in the agricultural systems of Ilam Province indicated that the top-priority actions to improve sustainability and increase the diversity of these systems are educating farmers, helping them reach economic stability and improving production management and water resources management.