Özet:

In this study, randomly selected farmer irrigations in the Harran plain were monitored, field slopes, flow rates, field irrigation lengths, Christiansen uniformity coefficient (CU) and distribution homogeneity (DU), deep infiltration rate (DPR), water application efficiency (Ea), irrigation efficiency (Ia), water requirement efficiency (Er), tail water ratio (TWR) were determined. It has been observed that large parts of the fields receive insufficient water during irrigation, the size of the flow rates and the irrigation times are estimated according to the experience of the irrigation. In border irrigations, strips consisting of three furrows have been formed. When the water reaches the end of the field in the furrow or border, the water is cut off and there is usually no tail water in daytime irrigation. moisture water deficit is not taken into account in irrigation. During irrigation, it has been determined that the land leveling is generally not sufficient for surface irrigation and there are even slope differences in the same field. It has been observed that one of the main and perhaps the most important causes of excessive water losses in the irrigation system in the Harran Plain is uncontrolled night irrigation. Even when the need for irrigation water is intense, the fact that the irrigation water flows directly into the drainage channels all night confirms this view. Due to over-irrigation in the whole field, deep infiltration increased and Ea value decreased to 62%. In some irrigations, it was determined that the entire field was insufficiently irrigated, while in an irrigation with an Ea value of 88%, it was determined that half of the land was over-irrigated and the other half received insufficient water. In field surface irrigation applications, the deep infiltration values varied between 9 and 38%, while CU values were found in the range of 66-96 in all irrigations monitored. On the other hand, while DU values generally vary between 46 and 85%, irrigation efficiency (Ea) varies between 62-91%, it is understood that high Ea values are due to incomplete irrigation. At the end of furrows and borders, furrows and borders are usually closed to limit or stop irrigation water from flowing into open drainage channels. Observations have shown that although field and soil characteristics are similar, different furrow/border lengths are used. In general, it was observed that the length of the field and the length of the furrow or border were equal, and the irrigation lengths in the monitored irrigations vary between 108-570 m. Since the price of irrigation water depends on the areal size and product type, not the water volume, a lot of water have been flowed into the drainage channels in an uncontrolled manner, especially in uncontrolled night irrigations. Therefore, high water losses occur, while huge amounts of water are discharged through drainage channels, some of it accumulates in the low-lying lands downstream of the Harran plain, causing groundwater to rise and drainage and salinization problems become widespread.

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