Abstract

Introduction
Mechanization is one of the main factors in the development of agriculture and is one of the examples of the application of technology in the agricultural sector, which makes it possible for the agricultural sector to reach the stage of industrial and commercial production. Agricultural mechanization, as a basic approach in the production of agricultural products, provides goals such as timely performance of agricultural operations, reduction of production costs, reduction of labor intensity, better management of agricultural inputs, quantitative and qualitative improvement of production and, in principle, the possibility of economic and mass production of products. There are inequalities in the development of agricultural mechanization, which is partly affected by natural factors, but human factors also play a significant role in its occurrence. Planning for the development of mechanization is one of the most important components in the development plan of the agricultural sector.
The requirement for correct planning regarding agricultural mechanization depends on recognition of the existing situation. In order to determine the existing situation and comparing the mechanization status of each region to another, there is a need to have defined and meaningful indicators and criteria. The consciousness of the current situation and the distance between different regions as well as obtaining the optimal level can be used to provide a suitable program and development of mechanization for finding and resolving the disturbances and inequalities. In this research, the indicators of rice mechanization in central and southern regions of Guilan province were investigated and compared. According to the results, the current state of mechanization of rice has been determined and the necessary solutions for their improvement have been provided.

Methodology
Guilan province is one of the northern provinces of Iran, with an area of 14711 square kilometers which stands the second ranking (31% of total) in terms of area harvested. A study was conducted during the years 2020 and 2021 for determination of indicators that govern the mechanization development in the central and southern regions of Guilan province. The studied areas were as rasht and khomam (in the central areas of guilan province) with an area under rice cultivation of 62430 hectares and roudbar (in the southern areas of guilan province) with an area under rice cultivation of 3375 hectares. The field method or field study was employed in terms of broad-based (holistic) and deep-based (depth-based) methods and its subset based on questionnaire for data collection in this research. Due to the lack of access to all villages of each city, one village was randomly selected and after checking their conditions, the relative homogeneity of the area was determined and the obtained information was generalized to other places. Collecting of data was done by completing the questionnaires through available statistical sources, field surveys and interviews with farmers. Data were collected from reliable authorities such as the Guilan agricultural jihad organization, agricultural jihad management of the cities, agricultural jihad centers, and the statistics of the Ministry of Agricultural Jihad. From the obtained data, the mechanization indices including degree of mechanization, mechanization level, mechanization capacity, machine power, machine productivity level, mechanization economic efficiency and machine farm efficiency were calculated.
The results revealed that in the central and southern regions of Guilan, the degree of mechanization was 65.1 and 78.9 percent, the level of mechanization was 2.71 and 9.12, horsepower per hectare, the economic efficiency of mechanization was 0.89 and 0.83 tons per horsepower, the average capacity of mechanization was 431.73 and 853.20 horsepower in hour per hectare, respectively. Transplanting by a 4-row rice transplanter in both regions had the highest productivity coefficient. The lowest productivity coefficient assigned to the spraying operation by a motorized backpack sprayer (4.72%) in the central areas and the mouldboard plow in primary tillage by a tractor (1.79%) in the southern region. On average, in the central and southern regions, there was one tractor for every 35 and 5 hectares, a tiller for every 5 and 11 hectares, a transplanter for every 46 and 31 hectares, and a combine harvester for every 88 and 56 hectares, respectively. For every 100 farmers, there were 3 and 5 tractors, 24 and 2 tillers and 2 and 1 transplanters, respectively.

Conclusion
The degree of mechanization for tillage and transplanting operations in the central and southern regions of Guilan province demonstrated a good circumstance based on the sixth state plan of development. According to the expectations, by the end of the sixth plan, the degree of mechanization in harvesting operation was acceptable in the south of Guilan, but in the central, in order to reach the expectations, there is a need to reinforce and import more machines for improving the level of mechanization. The degree of mechanization in plant protection operation for both regions had unfavorable situation. Therefore, measures should be taken for replacing appropriate machines. The level of rice mechanization was higher in the south region than the central. from the above-mentioned reasons, the level of mechanization of rice in the southern region can be attributed to the multiple usage of the driving machines for paddy fields and other crops, the low area under rice cultivation and the large number of tillers and tractors, the lack of companies providing mechanized services, and little time available to farmers to carry out land preparation, transplanting, protection, and harvesting in these regions. The findings also show that tractors and tillers, which are the most important sources of power supply, are not evenly distributed across the central and southern regions. tractors and other self-propelled machines have not been distributed based on the area under cultivation and the economic, climatic, and cultural conditions of the farmers. The smallholder farmers tended to possess a self-propelled machinery while this caused either unused power in rural areas or used only for a short period of time. In some cases, tractors and tillers were used in unrelevant tasks such as transportation and handling. The highest productivity coefficient in the central and southern regions were related to the transplanting by a 4-row rice transplanter. But the lowest productivity coefficient was assigned to the spraying operation by a motorized backpack sprayer (4.72%) in the central areas and the mouldboard plow in primary tillage by a tractor (1.79%) in the southern region. The low productivity coefficient of these machines has represented their lower usage in paddy fields. The highest mechanization capacity in the studied regions was related to the primary tillage by a tractor mounted moldboard plow. The lowest consumed energy in the central and southern regions were related to weeding by a three-row power weeder and spraying by a motorized backpack sprayer which were 18.25 and 8.32 horsepower-hour per hectare. Due to the high cost of purchasing self-propelled machinery and the smallness of the land, the average ratio of self-propelled machinery to operator was not appropriate, which brought the operators a great deal of weakness in performing operations at the proper time.