1 Department of Agroecology - Agrohydrology and Water Quality, Department of Agroecology, Science and Technology, Aarhus University2 Department of Agroecology - Climate and Water, Department of Agroecology, Science and Technology, Aarhus University3 Shiraz University4 Afgrødevidenskab5 Department of Agroecology - Climate and Water, Department of Agroecology, Science and Technology, Aarhus University
Plant growth and economic yield decreases when high salt concentrations build-up in the root zone. Quinoa is a facultative halophyte crop, which can withstand saline conditions. There is no documentation of the threshold soil electrical conductivity that cause yield reduction in quinoa under field conditions. In this study the threshold electrical conductivity of soil saturation extract (ECe) and maximum ECe corresponding to no economic yield of quinoa (cv. Titicaca) were determined. The experimental factors were five levels of saline solution (0, 10, 20, 30 and 40 dS m-1) imposed during flowering stage followed by either full irrigation (FI) with tap water, or progressive drought (PD), during the seed filling period. The FI0 yield was 2.45 t ha-1, which was not significantly different from seed yield of PD0. The maximum relative yield (with respect to the FI0 treatment) was 97% obtained in PD0 and the minimum relative yield was 47% observed at 40 dS m-1 saline solution (FI40). The results showed that quinoa can grow under highly saline conditions although the seed yield decreases with increased ECe. The threshold ECe of quinoa was estimated to be between 3-6 dS m-1. There was 50% reduction in seed yield of FI40 and PD40 treatments at ECe of 24 dS m-1. The ECe leading to no economic seed yield was xtrapolated to be 51.5 dS m-1. The results showed that quinoa can be classified as a salt tolerant crop according to the Mass and Hoffman classification.
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IICID 21st International Congress on Irrigation and Drainage, 2011