Agroecological zoning of Zanjan province for estimating yield potential and yield gap in dryland-base chickpea production systems

It is essential to understand crop yield potentials and exploitable gaps to detect yield constraints of crops. Yield gap analysis is a method to evaluate our systems distance from actual capability of a region to produce a given crop which will direct researches and help for cropping patterns design and programming. Moreover، knowledge on a region capability could result in investigating on given crop. Thus، this research was aimed to quantify water-limited potential yield، comparison of actual and potential yield and yield gap analysis of chickpea production in Zanjan province. Also Geographical Information System (GIS) approach was used to produce agroecological zoning maps. Averaged water-limited potential yield in Zanjan province was assessed as 727 kg ha-1 (varied from 559-1075 kg ha-1) using a simple simulation model of chickpea. With considering averaged actual yield as 408 kg ha-1 (average of three years، from 2009-2011)، mean yield gap was evaluated as 43% (varied from 24-59%)، which its average value is equal to 320 kg ha-1 (varies from 157-475 kg ha-1). The most important finding was the possibility of considerable increasing of yield in studied province in comparison with current yield. Our results on yield gap revealed that with covering of 80% potential yield، it is possible to increase yield from 5 to 95% (48% in average). Improvement of sowing، protection and harvesting managements are the main and lowest-cost options to fill the chickpea yield gap in Zanjan Province.