Document Type : Research Paper

Authors

• Hossein Beyrami
• Hossein Parvizi
• Amir Parnian
• Hadis Hatami

Assistant professor, National Salinity Research Center, Agricultural Research, Education and Extension Organization (AREEO), Yazd, Iran

Abstract

ABSTRACT
Introduction
Soil and water salinization is a worldwide problem, especially in irrigated areas, causing decrease in crop yield and the continuous loss of arable fields. Halophytes are the natural genetic source of salt tolerance traits and can be used for revegetation and remediation of salt-affected lands, and also as an alternative crop or biofuel. Due to the limited quality of water resources in the country and considering that the major regions of Iran's area are considered to be arid and semi-arid, it is important to cultivate plants with high tolerance to environmental stresses such as drought and salinity. The quinoa (Chenopodium quinoa Willd.) plant is important because of its ability to be cultivated in saline areas and irrigated with saline water. According to previous research, quinoa is an optional halophyte, and its irrigation is possible up to sea level salinity. Quinoa (Chenopodium quinoa Willd.) is one of the plants that has outstanding economic and agronomic advantages among the crops; it is particularly important in terms of forage production. There is no reliable and accurate information about the amount of water consumption by this plant in Iran. Considering the climatic characteristics and water shortages in the country, as well as the development plan for the cultivation of this plant due to its high nutritional value, attention to its water requirement becomes more important. For this reason, the importance of precise irrigation design and planning is needed in order to improve the performance of irrigation water usage in this region.
Materials and Methods
This research is conducted aim to determine the effects of different levels of moisture and salinity on the yield, some morphological traits, and some yield components of quinoa (Chenopodium quinoa Willd.) in field conditions during two growing seasons (2020-2022) in Yazd, Iran. The experiments were carried out in a factorial experiment in a randomized complete block design, which included two irrigation water salinity levels of 5 and 12 dS/m and four irrigation levels of 60, 80, 100, and 120% to provide the amount of allowable moisture depletion (MAD equal to 50%) in the root zone, in three replications. Experimental plots were designed with dimensions of 5×7 meters. Applying the amount of irrigation was done according to the determination of the field capacity levels and the permanent wilting point moisture measured (using a pressure plate device) before the start of the experiments. In this regard, according to this information, on the day of irrigation, the amount of soil moisture in each of the plots was measured at the root zone, and based on the treatments, the amount of water required was calculated, and irrigation was applied to the determined moisture level. Irrigation was carried out in the form of flooding, and the volume of irrigation water for each treatment was controlled by the volume contour and applied separately at each interval. At the end of the experiment, quinoa was harvested in a one-square-meter grid, and then plant height, panicle length and width, and stem diameter were measured. After the plant's drying, the weight of the seeds and the weight of the whole shoot were measured in different treatments.
Results and Discussion
The results showed that the different levels of salinity and soil moisture cause significant changes in biomass yield, seed yield, and harvest index. Also, the results indicated that changes in salinity levels and moisture levels caused significant differences in plant height, stem diameter and panicle length, panicle width, and 1000-seed weight (P<0.01), but their interaction was not significant. For two levels of salinity, the maximum biomass (9.28 tons/ha) was observed by supplying 100% of the depleted soil moisture based on MAD = 50%. According to the yield-water use function, the maximum seed yield for 5 and 12 dS/m irrigation water salinity was observed in treatments that supplied 115% and more than 120% of depleted soil moisture based on MAD = 50%, respectively. With the increase in salinity stress from 5 to 12 dS/m, biomass weight decreased by 23% and seed yield decreased by 17%. Based on the results, the average volume of applied water in fall cultivated quinoa under the 5 dS/m irrigation water salinity was 4900 m3/ha during the growth season (90 days).
Conclusion
In the autumn planting of the Titicaca variety of quinoa, with a planting period of about 90 days in arid and semi-arid regions like Yazd, water consumption is about 450 to 550 mm. But in conditions of moisture deficiency, it is possible to grow this plant. Because it has a lower yield reduction slope than other plants under drought and salt stress conditions. Furthermore, the results indicated that the salinity of the soil profile increased in deficit irrigation conditions (60% and 80% of depleted soil moisture based on MAD = 50%) due to the lack of leaching requirements.

Keywords

• Soil moisture deficit
• Maximum allowable depletion
• Salinity stress
• Yield

Main Subjects

• Soil, Water and Plant Relationships