Document Type : Original Article
Authors
1 Assistant Professor., Agricultural Engineering Research Department, Qazvin Agricultural and Natural Resources Research and Education Center, AREEO, Qazvin, Iran.
2 Professor,Agricultural Engineering Research Institute (AERI), Karaj, Iran
3 Assistant Professor, Department of Animal Sciences Research, Agricultural Engineering Research Department, Qazvin Agricultural and Natural Resources Research and Education Center, AREEO, Qazvin, Iran.
Abstract
Extended Abstract
Introduction
Despite the importance of determining indicators of water consumption management in the agricultural sector for use in national macro-planning, so far, indicators of water consumption management in the production of agricultural and horticultural crops have received less attention. This matter is of double importance regarding the programs to improve the efficiency of water consumption. In this regard, the determination of the volume of applied water, as one of the important and influential indicators in agricultural planning, should be considered. Therefore, conducting a research that can lead to more accurate information about the volume of water used for various agricultural and horticultural crops in the country is necessary, and its results can be of great help to the decision-making of officials related to water and agriculture.
The review of the conducted research showed that the accurate determination and monitoring of the current status of water consumption management indicators, including the volume of water consumed and the efficiency of irrigation water, as part of the important and influential indicators in agricultural planning in different regions of the world. Several studies have been conducted focusing on the analysis of the volume of olive water consumed in different places. Meanwhile, the researches done inside the country are mainly focused on the analysis of water needs, estimation of evapotranspiration, effects of lack of irrigation in different stages of growth and recognition of drought tolerant varieties of olives, and estimation of the amount of water consumed by olives. The monitoring of the current situation of water resources exploitation in olive groves in the country has received less attention. In this research, regardless the amount of water needed for evaporation and transpiration of olive plants, the amount of water consumed by olive growers in Qazvin province during the cropping season of 2017-2018 has been measured.
Methodology
Qazvin province is one of the main regions of olive production in the country, and the most important olive growing areas of the province are located in Tarom region, the area between Gilan and Zanjan provinces. The area of olive orchards in the province in 2017 was 9,300 hectares, and the area of fertile olive orchards was about 6,500 hectares. Also, the average yield of olives in the province is estimated at 2977 kg/hectare. This research was conducted with the aim of directly measuring the water consumption of olives in the olive production region of Qazvin province (Tarom region). Olive is the main product of gardeners in most villages of this region and is the only source of income for many villagers. So that more than 90% of gardeners' economy depends on the production of olives, and olives are their main product in 45 villages out of 105 villages in the region. In this regard, due to the severe limitation of water resources in the region and the development of new olive orchards, it is necessary to pay attention to the volume of water consumed by the orchards and plan based on the monitoring of the current state of water resources exploitation. In this research, measuring the amount of olive water consumed by considering various factors such as irrigation method, size of garden plots, soil texture, quality of water and soil resources, planting intervals and the level of education of the users were done. For this purpose, gardens for measuring water consumption were chosen in such a way as to cover the diversity of these factors. The volume of water given was measured with WSC flume (depending on the flow rate from type 3 to 5) or ultrasonic flow meter without interfering in the farmers' irrigation program. In the current research, in order to monitor the flow rate of the pumping station in drip irrigation systems, an ultrasonic flow meter device model PERCISION FLOW190PD was used and after the hydraulic test and calibration, the flow rate of the pumping station was measured in the selected gardens. After determining the amount of water entering the garden by carefully monitoring the garden irrigation schedule (watering time, irrigation cycle, irrigation times during the growth period), the amount of water consumed by the olive crop was measured for each of the selected gardens. Also, effective rainfall was estimated by SCS method. The water requirement of the reference plant was prepared and estimated using the Penman-Monteith method using the average data of the last 10 years for the target area from the nearest meteorological station. The water requirement of the reference plant was converted to the net water requirement of the plant by applying the plant coefficient. The yield of the crop at the end of the cropping season was also measured and the efficiency of water consumption was calculated and compared in each of the studied orchards.
Results and Discussion
The results showed that the range of irrigation water depth changes was between 5 and 30 mm with an average of 18 mm and a standard deviation of 17.7 mm. The minimum and maximum times of irrigations were 18 and 90 with an average of 39 and a standard deviation of 19.91. The average volume of applied water in the studied olive orchards in Tarom region was 6006 m3/ha with a standard deviation of 1517 m3/ha in all types of irrigation methods. The average yield of olives in the studied orchards in 2018 was equal to 5.46 tons/ha with a standard deviation of 4.8 tons/ha, which was higher than the average yield of olive in Qazvin province (3 tons/ha). According to the amount of water consumed and the yield, the average irrigation water efficiency in the studied orchards was 1.13 kg/m3 and the irrigation water efficiency and effective rainfall was equal to 0.78 kg/m3. In this regard, the highest index of agricultural water productivity index was recorded in dense olive groves of the region with the amount of 3.58 kg/m3. The most important reasons for the high agricultural water productivity index can be mentioned such as appropriate plant nutrition, proper fertilization of the land, soil texture modification, observance of horticulture principles, low-problem irrigation system, regular and correct irrigation cycle, and trained workers.
Conclusions
What can be concluded from this study is that water is not the only factor and input influencing the performance of olive product, several factors are also involved. In other words, the yield of the product can be increased even with less water consumption and with the management of other inputs and the technical and management conditions of the garden. This issue is very important in the country's water shortage situation where most of the trustees and operators focus on water management to increase performance. In general, it can be said that the performance of olive product, in addition to water, depends on various other factors, paying attention to each of them can play a more important role in improving performance and increasing productivity. Also, the comparison of the average volume of water consumed and the average water requirement of the olive crop indicates that the average amount of water given to olives (6006 m3/ha) is less than its actual requirement, both based on the recent 10-year meteorological data and it is also based on the information of the National Water Document. So, in general, it can be said that there is a lack of irrigation in the gardens. On the other hand, due to severe climate changes in recent years, there has been a big difference between the calculated values of the water requirement of crops and the information of the National Agricultural Water Document, which shows the need to update the National Agricultural Water Document in different regions of the country.
Keywords
Main Subjects
)