6.2. Impacts of reduced paddy fields on local environment

In the past few decades, in some developed countries and regions with long history of rice production, like Japan, Taiwan, and Korea, the area of paddy fields has been reducing, due to the changes of dieting system according to economic development and globalization, as shown in Figures 2 and 3. This reduction of paddy area might result in losing their multifunction with reduced rice production.

Figure 2. Changes of paddy cultivation area in Japan (source: [9, 19]).

The Japanese case of the reduction of paddy field area and its consequences are quickly reviewed. Japan had tried to establish complete self-sufficiency of rice historically, especially after the World War II. And then, it is finally realized in the 1960s, after long development investigation for improvement of paddy cultivation and fields including farming techniques and infrastructures of it.

rice production but also induces the changes of paddy irrigation system in the basin. The significance of paddy fields is to be reevaluated and reappreciated in terms of conserving the natural environment and sustaining the rural society and culture. The Japanese governments are challenging to revitalize agriculture and communities in rural areas, with some policy for conserving ecology and environment in rural area. The similar situation of reduced rice

Paddy Fields as Artificial and Temporal Wetland http://dx.doi.org/10.5772/intechopen.80581 155

In this chapter, implication of paddy cultivation and paddy fields is reviewed, focusing on

It is clear that paddy fields, paddy cultivation, and paddy irrigation need much water, land reclamation and preparation, and system to distribute water. Therefore, they have developed infrastructure, institution as well as interconnectedness of the farmers and other stakeholders. Significance of paddy fields as the artificial, temporal/seasonal wetland is to be assessed in comprehensive manner with aspects of agriculture, eco-environment, and hydrology. Since they use much water and might alter the local water balance and ecoenvironmental system with adverse effects, they are to be arranged appropriately in the hydrological and environmental regime of the region. Local communities established with paddy fields are to be organized continuously as the base for the society and culture and the potential to manage

consumption and paddy fields are seen in Korea and Taiwan.

Figure 3. Changes of rice consumption in Japan (source: [9, 19]).

flooding in the fields including its reasons and consequences.

7. Summary: concluding remarks

the future changes of environments.

Just after the reach to complete self-sufficiency, it had faced to the problem of over production of rice, which was caused by higher yield of rice, reduction of rice consumption with increased consumption of other food, including bread, meat as well as vegetables. The government asked farmers to convert their farm fields from rice to other crops with some portion of their farming plots, providing some subsidies. The rapid industrialization and urbanization also require paddy fields in the plain to be transferred to urban use. Consequently, the area of rice cultivation area has been decreasing as from about 3.3 million ha in 1960 to 1.56 million ha in 2017. It is a drastic reduction (Figure 2). During the same period, the rice consumption per capita per year of Japan has drastically reduced from about 127 to about 68 kg (Figure 3) [19].

With these changes, it could be easily recognized that the water ponding area, that is temporal water body or wetland, has reduced to the half of the peak, and the hydrological environment has been affected. It also means the degradation of multifunction of paddy fields. The wildlife is losing their habitats, and the biodiversity and the ecosystem developed historically have been modified.

In Japan, another problem is a reduction of farmers and their successors, which is another constraint to conserve paddy areas. The reduction of paddy fields means not only reduction of

Figure 3. Changes of rice consumption in Japan (source: [9, 19]).

rice production but also induces the changes of paddy irrigation system in the basin. The significance of paddy fields is to be reevaluated and reappreciated in terms of conserving the natural environment and sustaining the rural society and culture. The Japanese governments are challenging to revitalize agriculture and communities in rural areas, with some policy for conserving ecology and environment in rural area. The similar situation of reduced rice consumption and paddy fields are seen in Korea and Taiwan.
