Changes in temperature and precipitation on rice cultivation (case study of Zarin Shahr)

Abstract

Today, rice is the main food of more than half of the world's population and rice is cultivated in five continents and more than forty countries. Rice is one of the main meals of Iranian people, until 1340, Iran exported more or less rice every year, and since then, due to the improvement of the economic situation of the people and the rapid increase in population, despite the great measures taken by the government in providing large quantities of rice, the country has not been able to respond, and the country is also an importer of rice. Due to the existence of different climates in the country of rice in special weather conditions, the main limitations of rice production are the increasing shortage of labor, water shortage and changing the pattern of agricultural work from meeting needs to commercializing land, confronting the process of world trade liberalization, preserving natural resources, changing the pattern of food consumption, land ownership and production structure. In the new economic conditions, agriculture has lost its centrality to some extent, has become more complicated and is closely related to the global economy. The issues that agricultural development is currently facing are very different from the past. Adequate, basic and long-term investment for the production of new technologies such as hybrid rice and biotechnology seems necessary to increase production and meet the future food needs of mankind. Due to its importance in this research, it has been tried to evaluate the data through field, library and SPSS statistical methods to quantitatively evaluate different atmospheric factors and the effects of each on the growth of rice, so that by applying a correct agricultural management, the proper use of the nature of the studied area can be achieved.

Key words: rice, climate, Lanjan, Zarinshahr. Foreword

All agricultural plants are different from each other in terms of biological characteristics and environmental needs, while the physical characteristics of the earth's surface are also very different from one region to another. Many variables affect the growth and development of the plant, including. The length of the day, the amount of solar energy received, the amount of rainfall available for transpiration, the temperature during the growing season and the amount of nutritional mineral elements needed by the plant in the soil can be mentioned. Farmers can change and modify many of these variables, all of which are necessary for the successful growth of the plant. In dry areas, irrigation can be a supplement to rainfall, chemical fertilizers add nutrients to the soil, and the temperature and day length are also controlled by growing crops in closed environments where heat and light are under control. Can be corrected. But making all these changes in the natural environment requires spending a lot of money. Of course, there are also regions in the world where the growth of a particular crop plant will take place in the best way without making such reforms, and knowing the Chinese of these regions helps to explain the distribution of crop plants. (Greig, David, 2012, p. 26)

Temperature is one of the main determining factors in the geography of agricultural plants. Most of the plants in the temperate zone will not grow until the temperature reaches above 6°C, and this threshold is higher in the case of tropical plants. Low temperatures are dangerous and can delay germination in the spring, and severe frosts may kill growing crops. While early frosts in late summer damage crops that are ready for harvest, some autumn plants need low temperatures in winter, i.e. vernalization, to germinate in spring. (Greig, David, 1382, p. 35)

Soil moisture is essential for plant growth, because without water, plants wither and die, and crops cannot absorb the nutrients they need from the soil. Moisture affects crop growth in two ways. First, crops are very different from each other in terms of the amount of water needed to achieve optimal performance. For example, wheat and rye can grow in areas with annual rainfall between 25 and 100 cm. But tea needs more than 254 cm of rain to grow.

Secondly: There is a relationship between water storage and the performance of agricultural plants that does not have a linear trend. As the amount of water storage increases, it increases. But after reaching the optimal performance point, it decreases. (Greg David, 2012, p.(Greg David, 2012, p. 38)

In dry areas, it is not possible to produce crops without irrigation. In semi-arid areas, it is possible to grow crops without irrigation, but only a limited range of crops can grow in such conditions. The rate of yield is low and its fluctuations are high, and semi-humid areas have similar problems, but it is less obvious. (Greg David, 1382, p. 38)

Another problem is the seasonal distribution of rainfall, apparently enough rain is possible. It is concentrated in a very short season of the year, thus the range of cultivable crops is very limited, like what happens in the Sahel country. Or precipitation may occur in winter, while the optimal thermal conditions for the effective growing season are in spring and summer. But most of the problems related to rainfall and the growth of agricultural plants occur in semi-arid areas where the amount of rainfall is insignificant and fluctuates greatly from year to year.

By moving away from the optimal rainfall area, not only the amount of yield decreases, but the amount of fluctuation also increases from year to year. This event happens especially in semi-humid and semi-arid areas.

Thus, in the south of vast plains, with the decrease in rainfall, the percentage of crop failure increases. In areas of high rainfall variability, rainfall is often concentrated in one season, and is channeled through low pressure areas whose course varies greatly from year to year. (Greg David, 1382, p. 41)

When low temperatures cause freezing. Extracellular ice is formed. The reason for the spatial organization of freezing is not clear, but it is likely that it depends to some extent on the slope of the osmotic potential. Intracellular ice formation is thought to always be fatal. The formation of ice causes a decrease in leaf water and an increase in the concentration of soluble substances inside the cell, and in addition, at the same temperature, the water vapor pressure in the vicinity of ice is lower than the water vapor pressure in the vicinity of liquid water. These two features cause the movement of more water from the cell to the place of extracellular ice formation, as a result of which the cell tends to shrivel. (Woodward, F.I., 1374, p. 103) In this research, an attempt has been made to improve the quantitative and qualitative level of this product while examining the climate and its effects on rice cultivation in the Lanjan region.

This treatise is organized in five chapters:

Chapter One: General

Chapter Two: Natural Situation, Agriculture, Effects of Water and Climate on Rice Plant in the Region

Chapter Three: Method Research

Chapter Four: Statistical Analysis

Chapter Five: Conclusion and Suggestions

1-2 Introduction

Rice is the staple food of more than half of the world's population. Rice is cultivated in five continents and more than forty countries. From the equator to 45 degrees north, i.e. Hungary, and in the southern hemisphere to Australia, rice cultivation is common. All Iranians love rice, and most of the families who can afford to eat rice, dedicate one meal of their meal to rice as much as possible.

Until 1340, Iran exported more or less rice every year, and since then, as a result of the improvement of the economic situation of the people and the rapid increase of the population, despite the great measures taken by the government in providing large quantities of rice, our country has not been able to respond and is also an importer of rice.

Is it? You know that in the conversion of rice, each higher percentage of moisture is equal to one kilogram more rice and each kilogram of rice feeds 5 to 6 hungry people. (Mohammedzadeh-1389-p. 320)

The farmers of the areas around the Zainderoud river consider rice cultivation to be the most economical crop due to the lack of arable land and the presence of underground and running water, and the cultivation of this crop, in addition to the desire of the farmers, solves the problems. Socially and economically, Lanjan is a densely populated area. Due to the arrival of domestic and foreign cultivars in the region, none of the cultivars has yet been able to find a place because the domestic and foreign high-yielding cultivars often lacked quality or were not liked by the people, and the qualitative cultivars were not welcomed by the farmers due to their low yield.