In some parts of irrigated farmlands in arid areas, decreasing crop productivity caused by secondary salinization due to excessive irrigation and poor drainage has become a serious problem. Water saving is required in such areas, but it is not easy to shift to a more efficient irrigation method due to lack of funds and difficulty in procuring equipment. For these reasons, furrow irrigation, although causing large infiltration losses, is still being widely practiced.
In order to save water in furrow irrigation through the use of a method which can be easily adopted by farmers, a Simplified Surge Flow irrigation method (hereinafter referred to as ‘Simplified SF’), which is a simple version of the regular Surge Flow method (hereinafter referred to as ‘SF’), was contrived. In SF, water is applied intermittently, about 4 times by using pipelines and valves, to obtain water-saving effect. On the other hand, in the Simplified SF, a single furrow irrigation (conventional furrow irrigation) is just divided into two. In this research, the water-saving effect of the Simplified SF was verified on irrigated farmlands exhibiting remarkable secondary salinization in Uzbekistan.
In the furrow infiltration test, the cumulative infiltration at 60 minutes after the start of flooding, in the soil that has been supplied with water before one day, decreased by 9.5 mm compared with that of the dry soil; and the basic intake rate also decreased to less than 50%.
In the comparative irrigation test between the conventional furrow irrigation method and the Simplified SF on 100 m furrow (slope: 1/800), the speed of water advance during the second water supply by the Simplified SF increased, and the total duration it took for the irrigation water to reach the end of the furrow (irrigation time) was 6,026 seconds (about 100 minutes); this was 742 seconds (about 13 minutes) shorter than that of the conventional method, which had an irrigation time of 6,768 seconds (about 113 minutes). These results therefore showed that the Simplified SF could reduce the amount of water supplied to the furrow and the amount of oversupplied water by 11% and 15%, respectively.
This present study demonstrates the potential of the Simplified SF as an effective water-saving method in the developing countries facing water management problems. It should be noted, however, that the water-saving effect of the Simplified SF was lower than the 21% obtained with the use of regular SF in Fergana, Uzbekistan. In addition, stagnation of irrigation water due to the unevenness of furrows may have affected the water-saving effect of the Simplified SF. Therefore, to deal with the future challenges concerning the application of the Simplified SF in the field, it is necessary to consider optimal furrow length, as well as measures to suppress the influence of uneven furrows.
In the 1980s, there was a risk of desertification due to successive drought in Niger. In order to address the problem, Farmer Managed Natural Regeneration (FMNR), which aimed to develop agroforestry (AF) by selecting healthy sprout regenerated from the residual woody perennial root left in the field, was introduced. AF is to use the field three-dimensionally, and produce a large amount of biomass. AF contributes to prevention of soil and wind erosion, as well as to various effects such as improvement of soil fertility and field micro-meteorology. Several cases of desertification prevention by AF are discussed, and the direction of AF method which is inexpensive and easy for farmers to accept is examined.
The climate change is most influenced in the land at so-called a steppe country, such as Mongolia. Mongolia’s pastureland is degraded or desertified and to influence their ecosystem and way of life.Many Japanese NGO groups are conducting tree-planting program in Mongolia at present, but tree-planting work becomes wasteful for animal harm for much tree-planting program. Participation of a local resident is indispensable for promotion of the tree-planting program for the continuation. Tree-planting program requiring long term to get the profit, combination with the economical profit is indispensable for the success of the project. Prickly Plant KARAGANA to traditionally be worthless plant is converted into cash plant by Agro-forestry for the sustainability for the project. Increasing interest to the afforestation, an economic incentive, nomadic behavioral changes on TTM will be promoted.
We investigated land consolidation projects of paddy fields during recovery and reconstruction processes after the Great East Japan Earthquake in Miyagi Prefecture. Transitions in decision making and consensus building for restart of farming after a Tsunami disaster were analyzed, challenges in each stage extracted, and corresponding cases compared. Through a series of investigations, we verified usage and effect of various support measures prepared by the national and local governments based on the stage and work progress of the recovery and reconstruction processes. Measures that contributed to the recovery and reconstruction were as follows; 1) preparation of basic GIS data on agricultural infrastructure, 2) maintenance and formation of regional communities, 3) presentation of plans and goals by the national and local governments, and 4) provision of funds, human resources, know-how from outside, including financial support from the national and local governments. Through this study, we determined it is necessary to maintain and activate regional communities to prepare for large disasters.