Evaluation of the Saffron (Crocus sativus L.) Long-term Trend and Yield Stability in Razavi Khorasan Provinces

Monitoring of yield indicators, such as evaluating the trend and yield stability, can open the way for future policies and decisions in order to maintain and improve the yield of important agricultural products in Iran's agricultural systems. The aim of this study was to investigate and establish the stability of saffron yield in selected cities of Khorasan-Razavi province during the years 1400-1401 was conducted at Torbat Heydarieh University. To achieve this objective, data regarding saffron cultivation area and yield from various cities in Khorasan-Razavi Province were gathered from available statistics published by the Ministry of Agriculture Jihad, Iran, over 34 years (1365-1399). Following data validation, five cities – namely Torbat Heydarieh, Neishabur, Kashmir, Gonabad, and Taibad – were chosen based on the availability of comprehensive statistics. Additional information was then collated through questionnaires and forms by liaising with the agricultural jihad and research centers in each city. Utilizing regression analysis, this research delved into the long-term trends of yield and cultivated area, exploring relative and absolute yield residuals and investigating coefficients of yield changes. The study unveiled that the cultivated saffron area expanded across all surveyed cities until 2007-2008. However, in the latter years of the study, specifically in cities with high average saffron yield, such as Gonabad and Torbat Heydarieh, a marked decline in cultivated area was observed. Over the past 34 years, a notable decline in saffron yield has been observed in Torbat Heydarieh, Gonabad, and Kashmar. Notably, Gonabad, which had the highest average yield over this period, experienced the most substantial decrease in yield, amounting to 0.09 kg per hectare per year. Unfortunately, the degree of yield stability in the saffron cultivation ecosystems of the studied cities was not favorable. In particular, the relative residual yield across different cities ranged from 0.01% to 159.1%, indicating significant instability in saffron cultivation ecosystems within Khorasan Razavi province. The coefficient of variation of yield trends exhibited a decline in all surveyed cities except. The average rate of change in these cities was computed to be very low at -0.005% per year, implying that the enhancement of yield stability in these regions was occurring at a notably sluggish pace.