The effect of irrigation systems on the yield and productivity of paddy fields in Gilan province

Academic Thesis for Master's Degree

Field: Agriculture, Major: Agricultural Management

Abstract

Water is known as one of the most important basic resources in the development process in every human society. Water crisis is one of the important environmental challenges of the Middle East region. The present research was conducted with the aim of investigating and explaining the effects of different irrigation systems on the yield and productivity of paddy fields in Gilan province. This research is a part of quantitative research in terms of the dominant approach and is based on practical purpose. The statistical population of this research is the rice farmers of Gilan province. Using the table of the minimum sample size required by Bartlett et al. (2001), the sample size was determined to be 1064 and due to the low return rate of questionnaires in social and economic studies, 10% was added to the sample size. As a result, 1170 questionnaires were distributed, of which 1109 questionnaires were returned. By considering each irrigation method as a class (traditional, modern and combined), the stratified sampling method was used to select the samples. Also, taking into account the lack of proportional distribution of the studied irrigation methods in the studied cities, the available sampling method was used to select samples in each group and class. The data collection tool in this research was a questionnaire containing a number of closed and open questions. The formal and content validity of the questionnaire was determined using the opinions of specialists and experts, and the reliability of this study was also determined using Cronbach's alpha method of 5%. The central and dispersion statistics such as standard deviation and mean were used to rank and prioritize the items of different parts of the research. In the analytical part, the significant statistical relationships between the variables and also the type of relationships between the researched variables have been investigated, and for this purpose, parametric statistical methods such as analysis of variance or F test, Duncan's test have been used. In this study, the productivity indicators that Ehsani and Khalidi (2008) have used in their study on water productivity in agriculture have been used. In order to determine the non-parametric indicators of the partial productivity of the water input used in rice cultivation, CPD, BPD and NBPD productivity indicators have been used. Investigating the water productivity indicators of different rice varieties in paddy lands covered by three irrigation systems in Gilan province through the calculation and analysis of non-parametric indicators of the partial efficiency of the water input used in rice cultivation showed that the CPD index for all types of rice varieties in the three traditional, integrated and modern irrigation systems is equal to 0.215, 0.205 and 0.21 respectively. The results of the analysis of variance showed that there was a significant difference with a probability of 95% from the statistical point of view between the mentioned index in the above three irrigation systems and the result of Duncan's test also confirmed this difference between the integrated and traditional irrigation systems. The CPD index for native rice cultivars in three irrigation systems, traditional, combined and modern, was equal to 0.199, 0.197 and 0.2, respectively, and the results of variance analysis showed that there is no statistically significant difference between the three irrigation systems in terms of the mentioned index. The BPD index for different rice cultivars in three irrigation systems, traditional, integrated and modern, was equal to 8736, 8320 and 8498, respectively, and the results of variance analysis of the BPD index of various rice cultivars in three irrigation systems showed that there is a statistically significant difference with a probability of 95%, and the results of Duncan's analysis also confirmed the existence of this difference between the two irrigation systems, traditional and integrated. The NBPD index for different rice cultivars in the three traditional, combined and modern irrigation systems was 6775, 6382 and 6517 rials, respectively, and the results of the variance analysis also showed that there was a significant difference between the NBPD index of the rice cultivars in the three irrigation systems with a probability of 95% from the statistical point of view, and the results of Duncan's test also confirmed the significant difference between the NBPD index of the rice cultivars in the combined and traditional irrigation.

1-1- Introduction

Increasing population, agricultural development and the need to produce various food products in recent decades have led to heavy exploitation of the country's limited water resources. Although water covers three-fourths of the earth's surface, about three percent of the world's water is fresh and can be used in agriculture. According to the studies conducted by the World Food and Agriculture Organization in 93 developing countries, the excessive exploitation of water will lead to a decrease in water resources and as a result, endangering food security.. Although water covers three-quarters of the earth's surface, about three percent of the world's water is fresh and can be used in agriculture. According to studies conducted by the World Food and Agriculture Organization in 93 developing countries, the excessive exploitation of water has led to a decrease in water resources and, as a result, endangering food security. Based on the analysis of the International Institute of Water Management, there are two theories about the allocation of water for agriculture:

1 food supply for the growing population of the planet, water harvesting from surface and underground sources with a growth of 11%

2 optimal efficiency of water resources by increasing the efficiency of consumption in the agricultural sector

Our country has one third of the world's average rainfall and with 0.36% of the total renewable resources and 1% of the world's population will have a major contribution to this challenge, and in the meantime, the agricultural sector with about 90% of water consumption has the greatest mission in optimal consumption. Besides, the increase in physical efficiency without considering the increase in economic efficiency, which is called "water efficiency in economic production", will not have the desired and final result (Shayan Far, 2012).

Rice, along with wheat, are the two basic grains that provide the daily calories of the people of Iran, and Gilan province, having about 35% of the cultivated area and almost the same amount of production, supplies the food needs of about 18 million of the country's population. is Considering the important role of water in rice production, the need to investigate and pay attention to water productivity in paddy fields in the direction of sustainable production is of particular importance, and the investigation of water consumption management methods in Gilan paddy fields indicates that there are currently three types of water resource exploitation systems for the purpose of irrigation of fields (Gilaan Jihad Organization, 2018). They are mainly irrigated from the rivers of the internal basin of the network, and their area is over 62,277 hectares.

2- Modern land refers to a network that includes at least network 1 and 2.

3- Consolidated land (semi-modern) refers to a network that has one of the following characteristics:

A- It has a dam or a diversion dam. B- It has a catchment opening or the main water transfer channel.

Traditional lands are also referred to a network that lacks modern and consolidated characteristics of lands. In this research, the economic and social aspects of water consumption management in paddy fields have been investigated and water productivity indicators have been evaluated in three traditional, integrated and modern irrigation systems in order to attract more attention from planners and decision makers and to provide scientific and practical solutions by experts and specialists. rtl;">Water crisis is one of the most important environmental challenges in the Middle East region. Many experts are concerned that the use of water resources in Iran will cause serious problems in the future regardless of its limitations. The limitation of the country's water resources and the use of seed in irrigation, especially rice cultivation, has revealed the need to increase the efficiency of the valuable input of water in the cultivation of this crop (Darijani et al., 2013). In fact, in water productivity, the role of each unit of water in the gross national product or gross domestic product is discussed. If we look at water consumption in Iran from this point of view, the efficiency of water consumption in its productivity is very low in Iran (Alizadeh, 1380). In this situation, the most important challenge of the agricultural sector is to increase water efficiency and produce more food from less water (Dehghani, 1386). Due to Iran's location in the arid and semi-arid region of the world, as well as the occurrence of drought and water shortage in recent years, the issue of water has become the most important challenge for the country's agriculture. Rice farming, as an irrigated crop and a plant that needs more water than many other plants, on the one hand, and the need to maintain and sustain rice production on the other hand, makes addressing the issue of water even more important (Yazdani, 1385).

Gilan province has about 7.7% of renewable water in the country, and the volume of renewable water in Gilan is about 10 billion cubic meters, and the water requirement of the entire paddy fields of the province is about 3 billion cubic meters are estimated.