Saffron-pumpkin/watermelon: A clean and sustainable strategy for increasing economic land equivalent ratio under limited irrigation Alireza Koocheki * , Parviz Rezvani Moghaddam, Seyyed Mohammad Seyyedi Department of Agronomy, Faculty of Agriculture, Ferdowsi University of Mashhad, P.O. Box 91779-48974, Mashhad, Iran article info Article history: Received 4 June 2018 Received in revised form 4 August 2018 Accepted 18 October 2018 Available online 20 October 2018 Keywords: Crocus sativus Dormancy period Intercropping Irrigation scheme Land equivalent ratio abstract Generally, from the onset of dormancy to flowering, saffron farms are free of vegetation. Therefore, nutrients loss due to soil erosion, increased soil temperature and reduced land use efficiency are the most obvious problems of sole saffron cultivation, occurring over this period. Herein the intercropping advantage of saffron with watermelon or pumpkin and its effects on growth, yield and economic land equivalent ratio under limited irrigation were evaluated as a three-year field experiment (2014e2017) with a randomized complete blocks design arranged in factorial with three replicates. In this study, limited irrigation regimes on pumpkin and watermelon (14 and 28 days intervals) and cropping systems (saffron, pumpkin, watermelon, saffron þ pumpkin and saffron þ watermelon) were considered as the first and the second factors, respectively. Except for 2014, the individual effects of irrigation scheme and cropping systems on flower number and dried stigma yield were significant. In 2015, 2016, in comparison to saffron monoculture, intercropping significantly increased flower number and dried stigma yield. Moreover, in these years, increase in irrigation interval from 14 to 28 days significantly reduced average fruit weight in pumpkin and watermelon. The maximum land equivalent ratio and economic land equivalent ratio of saffron were found in saffron-pumpkin intercropping system with 14 days irrigation interval. Intercropping could positively affect saffron corms growth and N and P concentrations in the corms. In sum, considering the water shortage in arid and semi-arid regions, saffron-pumpkin or saffron- watermelon intercropping increases land efficiency and improves farmers’ income during perennial life cycle of saffron. © 2018 Published by Elsevier Ltd. 1. Introduction Saffron, a member of the Iridaceae family, is a spice derived from the flower stigma of Crocus sativus (Halvorson, 2008). It is culti- vated in arid and semi-arid regions of the world, especially in Iran (Khanali et al., 2016; Sepaskhah and Kamgar-Haghighi, 2009). In 2016, Iran's saffron cultivation area and production were 105,000 ha and 336 ton, respectively, which mainly are concen- trated in Northeast of the country in Khorasan-Razavi Province (Agricultural statistics, 2017). Accordingly, Iran is known as the most important saffron producer in the world as 89% of world's production is grown in Iran. The average saffron yield in Iran is about 3.2 kg ha 1 (Agricultural statistics, 2017). Saffron plays a vital role in the agricultural economy of the province where drought effects are most severe (Bouzarjmehri et al., 2016; Nasabian and Jafari, 2016). Low water requirement, specific growing cycle which is mainly during winter and having some unique morphological characteristics such as narrow and tough leaves make saffron compatible with arid regions (Azizi- Zohan et al., 2009; Koocheki and Seyyedi, 2016b, Koocheki et al., 2014; Mirsafi et al., 2016; Yarami et al., 2011). Saffron as a crop has a perennial life cycle (Koocheki and Seyyedi, 2015). Saffron is propagated through vegetative means using mother corms (Gresta et al., 2008; Rajaei et al., 2009). In botanical point of view, mother corms are modified underground stems with several buds (Kumar et al., 2009; Rubio-Moraga et al., 2014). These buds form new corms during growing season which called daughter corms (Koocheki and Seyyedi, 2015). After flower- ing in autumn, daughter corms start to form (Gresta et al., 2016; Koocheki et al., 2016a). In March saffron growth reaches to its maximum and in the middle of May daughter corms formation completed. At this stage, above ground parts dry out and daughter corms remain dormant until environmental conditions are * Corresponding author. E-mail address: akooch@um.ac.ir (A. Koocheki). Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro https://doi.org/10.1016/j.jclepro.2018.10.209 0959-6526/© 2018 Published by Elsevier Ltd. Journal of Cleaner Production 208 (2019) 1327e1338