ABSTRACT Laser land levelling has been widely adopted across Uzbekistan in recent years, particularly in the Khorezm Region. This transition has reshaped field configuration: small checks (≤ 0.5 ha), previously recommended for preplanting salt leaching, have increasingly been replaced by larger basins (2–10 ha or more). However, the implications of enlarged check sizes for leaching efficiency and water use remain insufficiently understood. This study evaluates the effects of check size on the amount of water used for salt leaching and leaching performance in laser‐levelled irrigated fields of the Khorezm Region. Field experiments were conducted at two sites using checks ranging from 0.3 to 7.0 ha. The results demonstrate that check size strongly influences the amount of water used for salt leaching, water advance, leaching duration and uniformity of salinity reduction. Small checks (0.3 ha) required approximately 1428 m 3 ha −1 and achieved full coverage within 2.5 h, whereas medium (≈3.44 ha) and large (6.5–7.0 ha) checks required 2349 and 3188–3210 m 3 ha −1 , respectively, with substantially slower advance and less uniform desalination. Root‐zone salinity decreased markedly across all treatments. Scenario analysis indicates that limiting the check size to ≤ 1.0 ha could save ~4.0 million m 3 of water per season in the Urgench District.
Eshchanov et al. (Thu,) studied this question.