Diversity of cropping systems in Iran

Function of agricultural ecosystems is based on genetic resources, management practices and also on biotic and abiotic factors. Genetic pools are indicative of biodiversity in agroecosystems and today this has a rather wider concept and includes all organisms of plat, animal, microorganisms and origins which contribute directly or indirectly to food products. Despite the ecological importance of biodiversity in agricultural sustainability, little attention has been given to this issue worldwide and particularly in Iran. For protection and utilization of agrobiodiversity, extensive understanding of their criteria and temporal and spatial distribution at all levels is required. In this study an attempt was made to evaluate agricultural biodiversity in Iran at all levels. For this purpose necessary data was collected from 183 countries in 27 provinces of the country and proper statistical analysis and different relevant indices was calculated. Present article is based on the first part of the series of articles prepared. Based on the results, distribution of all field crops, cropping systems, cropping intensity, rotation index and rotation efficiency index was investigated. It is apparent that there are two main cropping systems in the country, namely wheat -based and rice -based. The former is more extensive than the latter. Average cropping intensity index in the country is less than that for Asian, but it is comparable with the world average. Conventional crop rotation is not much diverse and all with short periods. This has caused a low efficiency for rotation systems. Polyculture has no significant role in this context and in general agricultural biodiversity at the ecosystem level is relatively poor and management tendency is towards monoculture of irrigated crops in short rotation periods. Keywords: Agrobiodiversity, Cropping systems, Crop rotation, Cropping intensity, Iran.