Document Type : Research Paper
Authors
1
Agricultural Engineering Research Department, Qazvin Agricultural and Natural Resources Research and Education Center, AREEO, Qazvin, Iran.
2
Associate Professor,Irrigation Systems Research Department, Agricultural Engineering Research Institute
3
Department of Water Engineering, College of Aburaihan, University of Tehran, Varamin, Iran
Abstract
Introduction
Traditional orchards are the gardens that are mostly outside the city. Typically, traditional orchards surrounding the city of Qazvin can be mentioned. The traditional Qazvin orchards, known for their 1400 years of existence, are one of the examples of optimal use of nature. The construction of traditional Orchards around the city of Qazvin shows that the person considered the way of peaceful living with nature more than ever, and pursued sustainable development, albeit with a slow process (Akhavizadegan, 2002). The features of traditional orchards, mixed cultivation, customs and traditions related to the division of gardens, the division of water and property. Traditional Orchards have been designed with a few goals. The first objective of the construction of this garden has been the direct and economical use of these gardens. The second cause has been the creation of green spaces around cities. This greenery encompassed the cities and made the cities appear as good-weather islands, even in arid and semi-arid regions (such as Isfahan, Shiraz and Qazvin). The third reason for the construction of traditional Orchards was to control the upstream floods and to prevent flood damage to farms and lower villages.
The results of various research studies indicate that the use of remote sensing techniques due to capabilities such as wide and integrated vision, the variety of data forms, digitally Data, providing timely and integrated data, wide and easy data availability, rapid access to remote locations and their high accuracy, can be used in large-scale planning in the water and environment study. (Aynew, 2003; Timmermans et al., 2007; Sun et al., 2011; Giorgos et al, 2017).
Considering the historical importance of traditional orchards, providing and identifying its water needs is one of the most important issues regarding the maintenance of gardens. However, due to the presence of traditional orchards on the outskirts of the city and the deviation of the outflow of flood during recent years, the debate has focused on the need to supply traditional alternative gardens to the traditional orchards. Hence, the first step in preserving and reviving these gardens is to estimate its water requirement. In this regard, due to the irregular cropping pattern of the mentioned gardens, estimating the need for traditional orchards using remote sensing facilities is considered.
Materials & Methods
The traditional orchards in Qazvin great importance due to historical dates and habitat of drought resistant species, frostbite, pests and diseases. On the other hand, such as seasonal flood management in these gardens, the importance of preserving these gardens has been doubled. The traditional orchards of Qazvin have spread in three directions in the east, south and west of this city, which in the past few days (less than half a century) has an area of more than 3,000 hectares of productive gardens (Akhavizadegan, 2002). Providing water for gardens has been one of the most important issues for gardeners since the past. Water scarcity has been indicative of the central role of water in the sustainability of gardens since the past and has been mentioned in historical records.
The traditional orchards in Qazvin are irrigated from four rivers called Arenjak, Bazar, Zoyar, Dalichay and a flood river called Weshteh in winter and spring. The waters of these rivers are mostly covered by melting of winter snow and spring rains from the northern mountains of Qazvin. The irrigation of traditional orchards mostly occurs twice a year, one in winter and one in spring. Due to the development of the city of Qazvin and the problems of exploitation and lack of attention to them, the area of traditional orchards around the city of Qazvin has declined in recent years.
In this research, ecological law is estimated in traditional orchards of Qazvin using remote sensing techniques and SEBAL algorithm, because SEBAL is an intermediate method that uses both empirical and physical parameters simultaneously (Terreza, 2006). The components of the SEBAL algorithm are more empirical and require less grounding information. The model includes a number of computational steps for image processing, the final calculation of evapotranspiration and energy exchange between the earth and the atmosphere (Kinoti et al, 2010). In the SEBAL algorithm, by using solar radiation reflections recorded by satellite sensors and using aerodynamic relationships, the amount of energy remaining is calculated as the energy necessary for the occurrence of the evapotranspiration process, followed by the amount of evapotranspiration at the moment Satellite passes will be obtained.
Landsat 8 satellite imagery is used in this research. Landsat satellite images are Path= 165 and Row= 35 are the main input data. The spatial resolution of the Landsat images is 30 meters and the width of the cover strip is 185 kilometers per image. The reason for the selection of the satellite images mentioned above was the high precision of the location and the availability of the images. The images were selected on days without clouds and dust. However, the important feature of the images used is that at the time of maximum water supply needs of the garden has been to provide water. Satellite imagery used to estimate the vegetation index of traditional orchards on dates 2013/06/19, 2013/7/21, 2014/7/21, 2014/7/24, 2015/06/25 and 2015/07/27 for the region studied. Since remote-sensing raw images always have errors in geometry (geometric errors) as well as values recorded for pixels (radiometric errors). Operations related to pre-processing, processing, performing corrections and calculations of image bands using ENVI software. To carry out the SEBAL algorithm, we need air humidity to obtain the temperature of the dew point and wind speed in the study area, which is also provided by Qazvin Synoptic Station.
Discussion of Results & Conclusions
The study of the level and density of vegetation index in traditional orchards around the city of Qazvin showed that despite the fact the area of green and semi-green gardens (in terms of the threshold of vegetation density) has been greatly reduced. The spatial distribution map of the vegetation index in the traditional orchards area showed that vegetation density index variations are very variable in the study area. In other words, on the basis of the vegetation map of the southern region of Baghestan, it is in a juicy situation. In the western and eastern parts of Qazvin, about 800 hectares of traditional gardening, despite the maintenance of land use, have very poor vegetation, thinness and in some cases it does not have vegetation. The results of this research and the researches have shown that remote sensing technologies can play an effective role in determining the maps of urban and suburban green spaces, vegetation density analysis, estimating the water requirement and providing an optimal model of water resources utilization. Make Estimated initial water requirement using remote sensing capabilities in traditional orchards that have ancient trees, different vegetation densities, varieties of crops and orchards and irregular crop types are important and effective in managing water resources and comprehensive management of green spaces. The results of satellite data show that if the accuracy of the images used is accurate when selecting the time, using the remote sensing data, factors such as classification and vegetation density and the amount of water requirement can be analyzed. Several studies have confirmed this (Jiang et al, 2010; James et al, 2009 Kundu et al, 2018; Grosso et al, 2018).
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