Saffron response to irrigation regime, salinity and planting method

Abstract

Demand for water is being increased due to population growth, urbanization and economic development in addition to drought occurrence. Using saline water, especially in arid and semi-arid areas is unavoidable in order to overcome increasing water demand and water scarcity. In this study the effects of irrigation water salinity (0.45 (well water, S1), 1.0 (S2), 2.0 (S3), 3.0 (S4) dS m−1), irrigation water levels (100% (I1). 75% (I2) and 50% (I3) of saffron water requirement (WR)) and planting methods (basin (P1) and in-furrow (P2) planting) on yield and growth of saffron plant (Crocus sativus L.) was investigated in open field conditions. Results showed that reduction in saffron yield which is caused by irrigation water salinity or deficit irrigation can be compensated by the in-furrow planting method whereas saffron yield for the in-furrow planting method was 2.06 and 2.21 times higher than that obtained in the basin planting method; respectively, in the first and second growing seasons due to lower soil surface hardness and higher soil surface layer temperature in winter for better flower emergence and saffron growth in in-furrow planting. Deficit irrigation aggravated the effect of salinity stress and yield reduction by decreasing the threshold ECe as 9.5% and 20.9% and increasing the slope of salinity-yield production equation as 51.3% and 112.5% in the 75% WR and 50% WR in comparison with that obtained in 100% WR, respectively. Yield reduction coefficient was lower in in-furrow planting method, especially in 50% WR as the coefficient in the in-furrow planting method decreased 21% in comparison with that obtained in the basin planting method. Finally, the results indicated that saffron yield is more sensitive to water stress than salinity stress. In general, the recommended irrigation regime in basin planting is 100%WR in salinity levels of 0.45-3 dS m−1; however, in in-furrow planting, it is 75%WR in 0.45-1.0 dS m−1 salinity levels, and 100%WR in salinity level of 2-3 dS m−1.