The Tungabhadra irrigation command area (TBP) in Karnataka, India, has three scenarios: the head, mid and tail reach command areas. The head reach has ample good quality canal water availability, and the mid reach area has limited canal water availability. In recent decades, rice–rice monocropping in vertisols, especially by these head and mid reach farmers, has led to not only water shortages but also the development of waterlogging and secondary soil salinization in the tail (lower) reach of the command due to seepage. As the soil salinity in the head reach was less severe, a slightly wider drain spacing of 60 m was adopted over 15 ha. In the case of the mid reach, salinity was slightly higher than the head reach but slightly less than the tail reach, hence 50 m drain spacing was laid out over 24 ha. Due to the slightly higher soil salinity at the tail end of the command, a closer drain spacing of 40 m was adopted over 11 ha. In all these scenarios, the drain depth was 1.0 m. Despite differences in irrigation water availability and different soil salinity conditions, the study clearly indicated over six seasons that the SSD system is a viable solution for the reclamation of waterlogged saline soils and enhancing rice productivity in all three scenarios of the TBP command.

中文翻译：

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印度卡纳塔克邦 Tungabhadra 项目指挥部不同情景下地下排水 (SSD) 控制内涝和土壤盐分的经济可行性

印度卡纳塔克邦的 Tungabhadra 灌溉指挥区 (TBP) 具有三种情景：头部、中部和尾部到达指挥区。上游有充足的优质运河水供应，而中游地区的运河水供应有限。近几十年来，尤其是这些上游和中游农民在垂直土壤中进行水稻-水稻单作，不仅导致水资源短缺，而且由于渗漏导致指挥部下游（下游）发生内涝和次生土壤盐渍化. 由于水头河段土壤盐分不太严重，在 15 公顷的土地上采用了 60 米的稍宽排水间距。在中游的情况下，盐度略高于头河段但略低于尾河段，因此在 24 公顷的范围内布置了 50 米的排水间距。由于命令尾端土壤盐分稍高，在 11 ha 范围内采用了 40 m 的较近排水间距。在所有这些情况下，排水深度均为 1.0 m。尽管灌溉水的可用性和不同的土壤盐分条件存在差异，但研究清楚地表明，在六个季节中，SSD 系统是在 TBP 命令的所有三种情况下开垦淹水盐渍土和提高水稻生产力的可行解决方案。