Effect of Different Organic Production Systems on Saffron Flowering

چکیده مقاله

Saffron, as a member of Iridaceae is an economically important crop, and currently has more than 330-ton annual stigma production in Iran, which includes near 90% of its world production. Saffron stigma has many household and industrial applications like as a colorant and flavoring agent in cooking as well as use in medical and perfumery industries. Nowadays, more attention is paid globally on saffron as a medicinal plant. Hence, to ensure a safe, residue-free and reliable material for use in herbal drug industry, there is an urgent need to adopt strategies for its cultivation that are consistent with principles of good agricultural practices. It has been reported that organic cultivation is an appropriate strategy for cultivation of medicinal plants to improve their quality and quantity [1]. Therefore, the aim of this study was to investigate the effect of three organic production system (OPS) on saffron reproductive growth criteria during two growth seasons. For this purpose an experiment was conducted at research field of University of Birjand, during 2015-2018. Treatments were included low (LI), medium (MI) and high input (HI) organic production systems. In LI, MI and HI-OPS, respectively, 15, 30 and 45 ton ha-1 cow manure in the first year (fall 2015, just before corm planting) and 5, 10 and 15 ton ha-1 in the second and third years (fall 2016 and 2017) was used. In addition, during each growing season 1, 2 and 3 times hand-weeding was used for LI, MI and HI-OPS, respectively. Corm planting was done in October, 2015 and flowering parameters were measured in autumn 2017 and 2018, when field was two and three-years old, respectively. Flower yield for the LI, MI and HI treatments was 114, 172 and 294 kg ha-1 in the second growing season and 120, 204 and 260 kg ha-1 during the third growing seasons, respectively. These values for stigma yield were 1.40, 1.97 and 3.78 kg ha-1 in the second flowering season and 1.86, 3.97 and 2.29 kg ha-1 in the third flowering season, for LI, MI and HI production systems, respectively. Overall, OPS especially HI-OPS improved saffron yield during both flowering seasons. It should be considered that organic manure application in soils with low organic carbon has high positive impact on saffron growth and flowering, but had no considerable effect in a soil with 1.0% O.C. Totally, a fertile soil is the basis for good saffron production, but organic manure represents the best support for saffron, especially under drought conditions, supplying nutrients, but above all, improving soil moisture and soil structure