Determining the Optimal Irrigation Amount and Salinity in Quinoa (Chenopodium quinoa) by Surface-Response Method

Document Type : Research Paper

Authors

• jalal gharibvan notorki ¹
• halimeh piri ²
• parviz haghighatjoo ²
• amir naserin ³
• mahdi asadi loor ⁴

¹ phd student, Department of Water Engineering, College of Water and Soil, University of Zabol, Zabol, Iran

² Department of Water Engineering, College of Water and Soil, University of Zabol, Zabol, Iran

³ Department of Water Engineering, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Ahvaz – Iran

⁴ Department of Water Engineering, Islamic Azad University of Ahvaz, Ahvaz, Iran

Abstract

Keywords

• Pulse Irrigation
• Fiber Percentage
• Deficit Irrigation
• Quinoa Quality

Main Subjects

• ..

EXTENDED ABSTRACT

Introduction

 Quinoa (Chenopodium quinoa L.) has been introduced as one of the crops to ensure food security in the world, which can tolerate water and drought stress to some extent. However, the development of its cultivation in the conditions of water stress and drought in Khuzestan province should be based on determining the limits of irrigation water and determining the threshold of tolerance to salinity. There are many methods to optimize the parameters in agriculture and each one is used for specific purposes due to having weak points and strengths. The use of small data that can be collected in the field is one of the basic factors for choosing the optimization method in agriculture. The response surface method is known as one of the modern optimization methods and its application in the agricultural sector is expanding day by day.

Materials and Methods

To achieve this goal, the present research was conducted in a research farm located in Baghmalek city, in the east of Khuzestan province, at the longitude of 49 degrees and 51 minutes east and latitude of 31 degrees and 41 minutes north in the crop year of 2022-2023. In this research, the quinoa plant was grown under drip irrigation and pulsed. Irrigation adequacy of 60 to 100 percent of water requirement (codes -1 to +1) was done in different plots. Water salinity treatments were applied at two levels of 0.5 and 0.6 deci-siemens/meter. Thus, in the condition of no salinity stress (code +1), pulse irrigation was done with three pulses of fresh water. But in the condition of complete salinity stress (code -1), pulse irrigation was done in three pulses of salt water. Level-response method was used to determine the optimal limits of these parameters.

Results and Discussion

By increasing the quantitative characteristics of the root, the dry and wet weight of the fodder also increases. On the other hand, this trend is not seen for qualitative parameters because no direct trend was seen between the increase of qualitative and quantitative parameters. The optimal level of irrigation water quantity and salinity is displayed in white. In fact, if the amount of irrigation water is between -0.3 and +0.5 and the salinity stress is considered between -1 and zero; The best mode is obtained to achieve optimal values. Of course, this range may not simultaneously increase the value of all quantitative and qualitative parameters. Based on the obtained results, the dry weight of fodder decreased to 6845.7 kg/hectare in the optimal condition. This amount is about 43% less than the maximum amount of fodder harvested in the field and equal to the average weight of dry fodder obtained in this research. The fresh weight of fodder also decreased to 24827.9 kg per hectare compared to the target value. This value is close to the average yield of fodder obtained in the research. However, the amount of fiber reached 15.9%. The percentage of fiber obtained in the research farm was between 14-19%, and the optimal percentage of fiber was about 5% less than the average percentage of fiber. The amount of soluble sugars in fodder reached 10.4%, which was about 4% more than the target amount. The dry and wet weight of the roots were calculated as 0.45 and 94.9 grams, respectively, which were 55 and 61% lower than the target values, respectively. The optimal amount of irrigation water was equal to 60% of the water requirement and the pulse method code was equal to zero. In fact, if the pulse irrigation method is done in the form of fresh water-salt water-fresh water and by providing 60% of the water requirement of the quinoa plant; Optimal values ​​will be obtained.

Author Contributions

J.Gh. conducted the experiment, measurements, analyses and drafted the frst manuscript. H.P wrote the original draft and editing. Other colleagues collaborated on the research as consultants. All authors have read and agreed to the published version of the manuscript.

Data Availability Statement

Data available on request from the authors.

Acknowledgements

The authors would like to thank the reviewers and editor for their critical comments that helped to improve the paper.The authors gratefully acknowledge the support and facilities provided by the Department of Water Engineering, College of Water and Soil, University of Zabol, Zabol, Iran.This work was supported by University of Zabol [grant number: UOZ-GR-1837].

Ethical considerations

The authors avoided data fabrication, falsification, plagiarism, and misconduct.

Conflict of interest

The author declares no conflict of interest.