Effects of irrigation times and sea-ice water with different salt concentrations on soil water and yield of cotton

In order to study the sea-ice water irrigation technology in the region near Bohai of China, the field micro-plot experiment was conducted to research soil moisture change and cotton yields using sea-ice water with different irrigation times and five salt concentrations (1, 3, 5L, 7 and 9 g/L) in 2008. The results showed that sea-ice water irrigation could improve soil moisture, especially during preplanting and seedling stage. The soil moisture content increased by about 22.85%-31.32% compared with CK (no irrigation) under the irrigation amount of 450 m3/hm2 each time could effectively relieve spring drought in cotton field. The cotton yields, boll number per plant and boll weight were the highest with sea-ice water of 1 g/L salt concentration (irrigated 3 times), which increased cotton yields by 38.63% compared with CK. The sea ice water of 3 g/L salt content (irrigated 2 times) increased yields by 29.8%. The cotton yields had decreasing trends with increased salt concentration of sea ice water used. The yields reduction rate with sea-ice water of 9 g/L salt concentration (irrigated 3 times) was 28.48% compared with CK (no irrigation). considering the desalinization technology, which and the long effects of salt concentrations of sea-ice water on soil and cotton yields, the results showed that sea-ice water of 3 g/L salt concentration could be used for cotton irrigation, in combination with drainage practices. In normal rain years, the sea-ice water could be irrigatted for cotton crops two times (before seedtime and at seedling stage) and irrigaton quantity was 450 m3/hm2 each time.