مدیریت بیابان (May 2023)
The Effect of Agronomical Management on the Growth Characteristics of the Forgotten Cannabis (Cannabis sativa L.) Plant in the Semi-Arid Climate
Abstract
IntroductionHarsh ecological conditions, including water scarcity, have limited vegetation life in desert areas. Consequently, the cultivation of drought-resistant plants compatible with desert areas and their expansion, while creating suitable vegetation, increases biodiversity, controls desertification and is oriented towards the sustainability of desert ecosystems. Cannabis is a drought-tolerant plant which, because of its great genetic diversity, has the ability to grow in different climates, particularly in semi-desert areas. Appropriate agricultural management enhances the vegetation, production and productivity of agricultural products. In this context, it is important to study planting date and plant density as factors impacting production. Planting dates must be chosen to allow sufficient time for each stage of growth and development. The use of optimal plant density may improve plant growth and increase plant yield by reducing intra-plant competition. Results of search on two densities of cannabis plants of 8 and 16 plants per m-2 in Birjand, the highest seed yield was obtained from a density of 16 plants per m-2. Finding on densities of 50, 150, and 250 plants per m-2 in Mashhad, and 30, 90, and 150 plants per m-2 in Shirvan reported that as the density of cannabis plants increased, the flowering date decreased in both regions. Given the arid and semi-arid climate of South Khorasan, planting plants compatible with the climate of the region, such as cannabis, can increase vegetation cover while producing an acceptable yield. The objectives of the current research are to study the effect of agricultural management on the growth characteristics of the forgotten cannabis plant in semi-arid climate of Birjand. Material and MethodsThe current research was carried out in Center of Agriculture and Natural Resources Research if South Khorasan, located at 59′ 13° east longitude and 53° 32′north latitude, and 1491m above sea level. South Khorasan province has a desert and semi-desert climate. Before preparing the soil to determine the required amount of chemical and organic fertilizers, the soil in the field was analyzed. Data on temperature changes and the total number of sunny hours of various months during the cannabis growing period were received from the Birjand weather station. The experiment was conducted as a split plot based on a randomized complete block design with three replications. Treatments investigated included planting date on three levels of May 12, May 27 and June 11 as the main plot and plant density at three levels of 22.2, 11.1 and 7.4 plants per m-2 as the sub plot. In this research, the phenological characteristics including the number of days to emergency, days to flowering, days to seed filling, days to physiological maturity, length of vegetative period, length of reproductive period, length of flowering period, and morphological characteristics including plant height, number of main stem branches, stem diameter and seed yield were investigated. Statistical analysis of the data was done using SAS software and the comparison of averages was done based on Duncan's 5% multiple range test. Results and DiscussionThe results showed that the impact of planting date on all morphophenological traits was significant, with the exception of stem diameter. The delay in planting between May 12 and June 11 significantly reduced the length of phenological stages, and vegetative growth of cannabis, and ultimately caused a 48% decrease in seed yield. Late cultivation, due to the increase in temperature, the plant completes its vegetative growth faster. The delay in planting by shortening the period of effective growth, reducing the photosynthetic potential of the plant, and coinciding with the period of seed filling with low temperatures and shortening of the day has led to a decrease in the quantity and the filling speed of the seeds, and subsequently the yield of the seeds decreases. It has been reported that a 20-day delay in seeding from 10 May led to a 46% decrease in seed yield under climatic conditions in Azerbaijan. The effect of plant density on morphological traits, number of days until flowering of female plants, days until seed set, days until physiological maturity, length of vegetative period, length of flowering period and seed yield were significant. The increase in density from 7.4 to 22.2 plants per m-2, while delaying flowering, increased seed yield by 15.4%. Increased plant density due to higher plant height and increased number of plants per unit area increased seed yield. Results of search on two densities of cannabis plants of 8 and 16 plants per m-2 in Birjand, the highest seed yield was obtained from a density of 16 plants per m-2. To achieve proper yield performance, and develop cannabis cultivation- as a plant compatible with the semi-desert region- the planting date of May 12 and the density of 22.2 plants per m-2 can be used.
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