Optimizing rainfed barley production by using nitrogen fertilizer and growth regulators in Khorram Abad and Poldokhtar agro-ecosystems

Document Type : Research Paper

Authors

• Saeideh Foladvand ¹
• Nosratolah Abbasi ²
• Fereshteh Darabi ¹
• Behroz Mir ³

¹ Department of Agronomy and Crop Breeding, Faculty of Agriculture, Ilam University, Ilam,I. R. Iran.

² Assis. Prof., Dept. of Agronomy, Faculty of Agriculture, Ilam University, Ilam, Iran

³ PhD in Agronomy, Lorestan Province Agricultural Jihad Organization,I. R. Iran.

Abstract

Keywords

• Spermidine
• Paclobutrazol
• Roots
• Chlormequat chloride
• Protein yiled

Main Subjects

• ..

_{EXTENDED ABSTRACT}

_Introduction

_{The projected growth of the world's population over the next few decades requires attention to the supply of food products to ensure the fulfillment of global demand. Due to the significant increase in the demand for barley and changes in the world's diet, one of the most important challenges faced by the agricultural sector in the last 20 years has been increasing the production of barley. Nitrogen is one of the widely used elements that plays an important role in the growth and physiology of agricultural plants. Therefore, a significant number of nitrogenous fertilizers is used to produce the product. Balanced consumption of chemical fertilizers, especially nitrogen fertilizers, seems necessary to achieve the optimal amount of the product and at the same time reduce the environmental risks. The use of growth regulators as one of the agricultural management solutions has been the focus of researchers. Growth regulators are made or natural chemical substances that are used directly with the aim of changing some structural processes of the crop plant. These substances improve the balance of hormones and growth in the plant and lead to an increase in quantitative or qualitative yield in the crop plant.}

_{Materials and Methods}

_{Research was conducted in two regions in the crop year of 2022-2023 in Poldokhtar and Khorram Abad cities. The experiment was carried out as a factorial design in the form of a basic randomized complete block design with three replications. The first factor includes four levels of nitrogen chemical fertilizers, including 0, 50, 100 and 150 kg.h-1 urea, and the second factor was foliar application of blank (spraying solution with distilled water), paclobutrazol (120 mg/liter), spermidine (1 mM), and chlormequat chloride (three grams per liter). Each test plot included 12 planting lines 4 meters long and with a distance of 20 cm from each other and the distance between the plots was considered to be half a meter. The number of plots in each block was 16 and in each experiment 38 plots, and the distance between the blocks was determined to be about one meter.}

_{Results and Discussion}

_{The average comparison results showed that the highest root dry weight was observed in the treatment of 100 kg.h-1 nitrogen fertilizer and chlormequat chloride foliar spraying at the rate of 7.25 grams per square meter, and the lowest amount in the absence of nitrogen fertilizer and foliar spraying at the rate of 4.45 grams. It was obtained in square meters. The highest seed yield was observed in the treatment of 100 kg.h-1 nitrogen fertilizer and paclobutrazol foliar spraying at the rate of 2686.4 kg/ha, and the lowest rate was obtained in the absence of nitrogen fertilizer and no foliar spraying at the rate of 1284.8 kg/ha. The highest protein yield was observed in the treatment of 100 kg.h-1 nitrogen fertilizer and paclobutrazol foliar spraying at the rate of 313.25 kg per hectare, and the lowest amount was obtained in the absence of nitrogen fertilizer and foliar spraying at the rate of 102.53 kg per hectare. The average comparison results showed that the highest total chlorophyll was observed in the treatment of 100 kg.h-1 nitrogen fertilizer and paclobutrazol foliar spraying at the rate of 10.38 mg/g of fresh weight, and the lowest amount was observed in the absence of nitrogen fertilizer and no foliar spraying at the rate of 5.88 mg/g fresh weight was obtained.}

_Conclusion

_{According to the results of this study, the use of nitrogen fertilizer and foliar application of growth regulators can significantly improve the quantitative and qualitative performance of barley in rainy conditions. Nitrogen fertilizer has increased the growth and yield and photosynthetic pigments of the barley plant. It seems that in rainy conditions, the plant was able to use nitrogen at the rate of 100 kg per hectare, probably in rainy conditions, where the amount of rainfall is strongly related to climatic and atmospheric conditions, the humidity was low during planting, and nitrogen, because it has a high correlation with available water, less has been able to be provided to the plant. In general, the use of nitrogen fertilizer at the rate of 100 kg per hectare and paclobutrazol can significantly improve barley production in rainy conditions in the two regions of Poldokhtar and Khorram Abad.}

_{Author Contributions}

_{Methodology, software, formal analysis, writing—original draft preparation, S.F; conceptualization, visualization, investigation, validation, resources, data curation, supervision, N.A.; writing—review and editing, F.D.; writing—review and editing, B.M}

_{All authors have read and agreed to the published version of the manuscript. All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.}

_{Data Availability Statement}

_{“Not applicable”}

_{Ethical considerations}

_{The authors avoided data fabrication, falsification, plagiarism, and misconduct.}

_{Conflict of interest}

_{The author declares no conflict of interest.}