Comparison of the environmental indicators of phosphorus efficiency and the balance between saffron and wheat production systems in the Qaenat region, Iran

Improving the resource use efficiency in agro- ecosystems is an important factor for reducing environmental pollution. To evaluate phosphorus (P) efficiency and balance indicators, research was conducted in wheat and saffron production systems in the Qaenat region (South Khorasan Province, Iran) during 2011 and 2012, based on the method of the Organization for Economic Co-operation and Development (OECD). The required information about wheat and saffron cultivation was collected via questionnaires and the required coefficients were obtained from various literatures. The results showed that the phosphorus efficiency and balance indicators were significantly different between distinct districts only in the case of wheat crops. The highest P efficiencies of wheat and saffron farms were 7.21% and 2.93%, respectively. Additionally, P efficiency and balance indicators showed a significant difference between both crops in some districts, so that wheat had higher P efficiency than saffron, which was mainly because of the different amounts of animal manure applied to these crops. There was no significant difference between the different ages of saffron farms for P efficiency and balance. Furthermore, there was a significant negative correlation between P efficiency and balance indicators. It would appear that there are many opportunities for improving the efficiency of P and to prevent environmental pollution through the optimization of management decisions.