Document Type : Research Article
Authors
Assistant Professor, Department of Agriculture, Payam Noor university, Tehran, Iran
Abstract
Introduction
Drought stress is one of the most important and most common limiting factors for plant growth in arid and semiarid regions. Asparagus (Asparagus afficinalis) is the most important species of asparagus and the fresh stem of this plant is harvested as its edible part and used as a vegetable and medicine. Asparagus is very rich in vitamins, flavonoids, saponins, and glutathione, which have anti-cancer properties, protect nerve cells, and protect the heart. Asparagus is a herbaceous, perennial plant growing to 100–150 cm tall, with two types of stems. One of the stems called spear, which is edible and has no leaves. The second, called fern which has needle leaves and is non-edible. This plant has thick and fleshy roots called rhizome (crown), which is resistant to winter cold and can remain in the ground for up to 25 years and give economic crops for up to 10-15 years. According to some studies, commercial cultivars of asparagus are sensitive to abiotic stresses such as drought stress. Drought stress during the growth of fern can reduce the production of stored carbohydrates in the crown roots and lead to a decrease in yield in the next season. Also, drought stress increases the fiber and reduces the quality of asparagus. Mulch is any material that is spread or laid over the surface of the soil and used for reasons such as saving water consumption by reducing evaporation from the soil surface, controlling soil erosion, adjusting soil temperature, controlling the growth of weeds, and improving the absorption of soil nutrients. Several researches have reported that the use of mulch is effective in increasing the resistance of plants to drought stress and also reducing the negative effects of drought stress on yield and its components.
Materials and Methods
This research was conducted as a factorial experiment based on a randomized complete block design in three replications in the crop year of 2021-2022 in a two-year asparagus field near Mashhad city. The experimental factors were the types of mulch (barley straw, asparagus straw and plastic) and drought stress levels including irrigation after 50 mm (no stress), 70 mm (mild stress), 100 mm (moderate stress) and 150 mm (severe stress) evaporation from pan class A. Planting of transplants in the field was done manually on April 9 2021. Each experimental plot with dimensions of 4 x 10 meters included 4 rows with a distance of 100 cm and a distance of 50 cm between plants. Weeding was done manually. Fertilization was done according to the soil analysis and the recommendations of the soil science laboratory. The date of applying water stress was from April 4 to September 1 2022. The average of traits recorded in the first harvest (April 21) and the second harvest (September 6) were used for variance analysis. Data analysis was done using MSTAT-C software and mean comparisons were done using LSD method at 5% probability level. The graphs were drawn using Excel software.
Results and Discussion
The results showed that fresh stem yield, number of harvestable stems, stem length, stem diameter, stem fresh and dry weight, and total leaf chlorophyll content decreased and leaf proline content increased significantly at different levels of water stress. The content of leaf carotenoids also decreased significantly compared to the control only in severe water stress. The use of mulch in non-stressed conditions caused a significant increase in all studied traits except proline, so that asparagus straw with a 76% increase in stem yield was in the first place, and barley straw and plastic mulch were in the second and third places. Also, mulching reduced the negative effects of water stress on all traits, so that the non-use of mulch in mild, moderate and severe stress caused a 21%, 36% and 46% reduction in shoot yield, respectively, and the use of asparagus straw caused 10 %, 13% and 16% decrease in the yield of stems.
Conclusion
Water stress, as the most important factor of physiological limitation in plants, negatively affects growth, development and yield of plants. The use of plant residue mulches, especially asparagus straw, between the rows of asparagus cultivation can increase the yield in conditions without drought stress, and in drought stress conditions. the yield can be protected from the negative effects of stress to a large extent.
Keywords
Main Subjects
)
Send comment about this article