Saffron response to irrigation water salinity, cow manure and planting method

Abstract

Saffron (Crocus sativus L.) is the most strategic and expensive crop in the Islamic Republic of Iran. Shortage and salinity of irrigation water are two major constraints that influence saffron production in arid and semi-arid regions. The objective of the present study is to investigate the effects of irrigation water salinity, cow manure levels and different planting methods as strategies for coping with the impacts of salinity on yield and growth of saffron. Experimental design was a split–split plot arrangement in randomized complete block design with salinity levels of irrigation water as the main plot, cow manure levels as the subplot and planting method as the sub-subplot in three replications. The salinity levels consisted of 0.45 (well water, S1), 1.0 (S2), 2.0 (S3), and 3.0 (S4) dSm−1. The fertilizer levels were 30 (F1) and 60 (F2) Mgha−1 of cow manure for the first growing season and 15 and 30Mgha−1 for the second growing seasons. The planting methods were basin (P1) and in-furrow (P2). Saffron (stile/stigmas) yield declined by about 38% by increasing water salinity to highest level. Saffron yield in the in-furrow planting method was higher than 3.5 times that in the basin planting, which indicates that the in-furrow planting method can be recommended as a highly efficient method for saffron planting, by providing a probably appropriate soil temperature condition for corms growth. Higher cow manure application (60Mgha−1) increased saffron yield by about 23%, due to improving soil fertility and supplying the nutrient requirements of plant. Maximum threshold ECe for saffron yield was 1.1dSm−1 that occurred under in-furrow planting method and cow manure application rate of 60Mgha−1 and saffron yield reduction coefficient was on average 40% per unit soil salinity increase. Finally, saffron can be considered as a salt-sensitive crop. High salt sensitivity of saffron could be remediated by using the in-furrow planting method and cow manure application.