As part of the joint research conducted by Japan and China on the agricultural development of the Mu Us Shamo Desert, surveys on soil physical properties, moisture consumption, and the irrigation effect have been carried out on several plants in the fields of the Mu Us Shamo Research Center since 1985. Using these results, schedules were established for the irrigation of a pilot farm which was constructed at the Research Center in 1991.
The irrigation schedules were mainly based on the design guidelines of the Ministry of Agriculture, Forestry and Fisheries of Japan. As a result, the dimensions for the irrigation interval and water quantity per irrigation unit were estimated under the various plants in the pilot farm. From these design dimensions and the daily rainfall measured during the past 27 years, the net water requirement was estimated considering the effective rainfall. Also, the characteristics of the irrigation and rainfall could be explained by discussing the ratio of the total net water requirement to the total evapotranspiration, which subsequently indicates the factors in the pilot farm's future water management.
Finally, in order to prevent the salinization of soils and groundwater and to select suitable irrigation methods, some recommendations are given for better use of technology in conservation management for the pilot farm.

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In areas of low canal density, irrigation water may take a long time to reach its destination. This is due to the long distance involved between irrigation canals and drainage canals. Such low levels of irrigation canal density require high levels of water evaporation, meaning that the total water requirement under such conditions is large.
In this study differences between areas with tertiary canal irrigation (Muda II project area) and those without tertiary canals (Muda I project area) were compared. Particular note was taken with regard to, first, the different progress of presaturation water and, second, the different amounts of water required under each type of irrigation condition. Two irrigation blocks with tertiary canal facilities and two without them were selected and compared from both coastal and inland areas in the first cropping season (dry season) of 1988, and the differences in the progress of presaturation water due to the differing levels of canal density and topographical gradients were noted. Water requirements were lower in the areas provided with tertiary irrigation facilities than in those without tertiary canals in both the coastal and inland areas.

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In many Indonesian food crop fields, paddy rice is cultivated in the rainy season and other, secondary crops are grown in the dry season. Those secondary crops usually suffer from excessive water conditions due to the plowsole layer formed through paddy rice cultivation. This study simultaneously analyzes the effect of excessive and deficient water conditions on crop yields by the newly revised stress day index (SDI) method, which consisted of two indicators related to two bounds, upper and lower, of the appropriate range of soil water conditions for crop growth. The proposed SDI showed a high degree of linear correlation with soybean yield observed in experimental fields. The results of other methods which merely analyzed soil water deficit are compared with that of the present study, and advantages of the proposed method are indicated.

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Flow conditions which could not be explained occurred in the stilling basin and outfall channel of the 40-vent main regulator of the Muhuri Irrigation Project in Bangladesh. Analysis of flood discharge data revealed that the design discharge for the structure was not exceeded; yet abnormal scour occurred in the outfall channel, and the brick block rip-rap placed thereon was damaged. A model study was conducted to understand the causes of such unusual local erosion downstream of the stilling basin and to provide answers to two main questions:
-Is potential scour serious in terms of the stability of the structure?
-What protective measures could be taken to stabilize the scour at a safe level?
Using a 1: 30 scale model, the probable maximum scour was simulated, and the performance of alternative rip-rap designs, including that of the existing one, were examined. The results of this study supplemented by field scour data collected during subsequent flood seasons indicated that even if the flow rate through the regulator approaches the design flood discharge, the downstream scour is not likely to extend up to an elevation of -10.7m, a scour level observed in the previous year at a lower discharge level. It also showed that the existing rip-rap blocks were marginally undersized and that consequently the rip-rap was prone to failure if flow conditions departed from the uniform. A suitable method of scour protection downstream of the stilling basin at the regulator exit also evolved from the study.

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An investigation was organized to determine the present state of leveling accuracy of paddy fields in Thailand. Different types of paddy fields were selected and evaluated for their leveling accuracy, which has been expressed in terms of range and standard deviation by measuring surface elevations at grid points. In most places, it was observed that these values varied widely from place to place. These indices are influenced by plot size, investment cost and farmers' enthusiasm. The repercussions of leveling accuracy on other factors like grain yield, bund height and machinery were also discussed.

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