Comparison of different optimization based land reallocation models

Highlights

• Land consolidation (LC) is a tool for supporting rural development.

• One of the most important steps of LC projects is land reallocation studies.

• MBO and SA algorithms were used for the first time in land reallocation.

• A fast, accurate and low cost land reallocation can made with MBO and SA algorithms.

• In terms of percentage of success, MBO method is more preferable than SA method.

Abstract

Land reallocation, which is an optimization problem in the field of engineering, is the process of reallocating parcels to pre-determined blocks according to the preferences of landowners. In practice, this is done manually and takes weeks or even months. The elongation of this process affects both the cost of the project and the project's acceptability by the landowners and thus the success of the project. Because the success of land consolidation projects is determined by the satisfaction of the landowners. For these reasons, the optimization-based land reallocation studies have been extensively carried out recently. However, these methods in the literature are not used in practice and the reallocation is still done manually. Therefore, for the first time in this study, two new reallocation models were developed to solve this problem by using Migration Birds and Simulated Annealing Algorithms and the results of these methods in a real project area were compared. Additionally, the results were compared to the conventional reallocation method (manual reallocation) to evaluate the performance of the methods developed. Both proposed methods provided a successful and practicable reallocation plan in a very short time with respect to the conventional one.

Introduction

As the world population is increasing rapidly, the importance of limited natural resources such as soil and water is gradually increasing. As a result of the rapidly growing population, food demand and security of the growing population can be provided by investing and supporting agricultural activities. For sustainable food security, the efficiency of agricultural land must also be ensured. One of the problems of current agriculture is land fragmentation. Land fragmentation has a detrimental effect on land use and agricultural productivity (Boonchom et al., 2017). Land fragmentation is the biggest barrier to sustainable agriculture and is a global problem largely related to agricultural activities. A primary method of circumventing this barrier is legislation to prevent more land parcels being broken up and to ameliorate existing difficulties. This is known as land consolidation (LC) (Cay and Uyan, 2013). LC is a land management tool that solves the problem of land fragmentation and increases agricultural productivity. Asian countries such as China, India, Nepal, Uzbekistan and Japan have been conducting land consolidation projects to increase agricultural productivity and improve rural infrastructure (Li et al., 2018). These projects have become a tool used to improve the quantity and quality of the cultivated areas, reduce the land fragmentation, regulate the land ownership structure, increase the modern agricultural development, beautify the rural environment and support the rural development and poverty reduction (Jiang et al., 2017).

Land consolidation projects in Turkey were carried out for the first time in 1961. Since then, 6 150 283 ha areas have been consolidated. Completing a 7.9 Million hectare-land consolidation project between 2018 and 2023 is among Turkey's-strategic plans. Namely, the 1st Generation Land Consolidation project of Turkey will have to be completed in the near future. Hence, the construction of these projects needs to be accelerated. This is only possible with the use of computer-based technology. Land consolidation projects in Turkey are performed whether by the request of the landowner (optional consolidation) or in the cases where the public benefit requires (mandatory consolidation). After taking the land consolidation decision, many steps are taken in these projects. One of these steps is interviews with landowners. During the interview, the landowner must report the parcels he owns and if he has a fixed facility. Fixed facility in the project area: it refers to structures such as house, barn, hayloft, warehouse, licensed well, and agricultural lands that are fruit orchards. Landowners often want to take their land from blocks with fixed facilities, the largest parcel, or the majority of the parcels. Landowners who do not prefer are reallocated from blocks with old parcels. However, interviews are required to obtain optimum efficiency from the project and to reduce the objections of landowners at the end of the project. The duration of a land consolidation project in Turkey depends on the size of the land but takes an average of 3 years. However, in case of an objection by the unsatisfied landowners, this period extends.

Land consolidation in Turkey is carried out with four major steps: pre-survey, planning, project and implementation. Land reallocation is the most important process in which the parcels are placed in predetermined blocks. In the conventional method, this placement is performed according to the preferences of the landowners and is called interview-based reallocation method. The parcels should be placed in the most suitable block as a single parcel as much as possible by taking into consideration the requests of the landowners. In addition to farmers’ requests some technical requirements such as, fixed facilities, road and irrigation network, optimal parcel size, parcel geometry, parcel size, social factors need to be taken into consideration when placing parcels in blocks. The new parcels to be created at this stage are tried to be placed to the best and most appropriate place of the existing blocks according to these parameters. It is clear that this placement does not have a single solution. If a problem does not have a single solution, it is necessary to find the best one. The best and most appropriate in here is according to the available parameters. It will also depend on the person modelling “the best solution” problem. Given all this, this is an optimization process of placing new parcels in blocks.

The issue of optimization in land consolidation has been analysed by many researchers in the last few years. For example, Leń (2018) studied to develop a universal algorithm for selecting groups of factors for purposes of prioritization of land consolidation which takes into account the geographic location of an investigated area. Kwinta and Gniadek (2017) proposed a methodology for obtaining parameters of the geometry of parcel description, which supports the process of decision-making in the field of land consolidation works. Martínez et al. (2013) developed a GIS-based semi-automatic software for the LC process. In scientific research in Turkey, optimization studies has carried out based on mathematical models for the reallocation process. These studies are: fuzzy logic application in reallocation (Cay and İscan, 2011), implementation of spatial decision support systems in block reallocation (Uyan et al., 2015), application of genetic algorithm and hybrid methods in reallocation (Ertunc et al., 2018). However, these studies could not be implemented due to legal procedures and partly they need manual intervention.

Land reallocation stage of land consolidation projects in Turkey is still performed manually and this situation causes many problems. Therefore, in this study, two new reallocation models were developed by using two different optimization methods to overcome this problem and the outcomes of these methods were compared in a real project area. Additionally, the results were compared to the conventional reallocation method to evaluate the performance of the methods developed.