| As agricultural irrigation water, sea-ice water has great potential because of the richness of water resources and low salt concentration. This paper based on previous studies, the relevant field irrigation experiments have been made in terms of the safely and efficiently agricultural use of sea-ice water resources. A field experiment was conducted on the Zhongjie Farm of Hebei province to research the temporal and spatial change of soil moisture and soil salinity by different irrigation condition from April 2007 to November 2008. Discussion on the sea-ice water safe efficient utilization index system and matching technology. The main conclusions are as follows:1. The effect of soil water dynamics under sea-ice water irrigation: (1) Sea-ice water irrigation can obviously improve soil moisture, especially at before seedtime and seedling stage. The increase amplitude was 22.85%～31.32%. It can effectively relieve spring drought in cotton field. Soil moisture increases with increasing irrigation times. (2) High salinity density is beneficial to water infiltration, so increasing middle and lower layer soil moisture. b-3 compared with a-3 the most soil moisture increase amplitude at 20～80 cm; 5g/L and 7g/L soil moisture increase amplitude at 60～80 cm and 40～100 cm.2. The effect of soil salinity dynamics under sea-ice water irrigation: (1) Sea-ice water irrigation is mainly beneficial to leaching of 0～40cm root layer soil salinity at seedling stage. Different irrigation treatments compared with CK has decreased 20.75%～54.64% and 1.08%～62.16% at the 0～40 cm soil salinity at seedling stage and boll opening stage. Every sea-ice water irrigation treatments soil salinity are higher than CK under 40cm. Therefore, Sea-ice water irrigation could effectively leaching root layer soil salinity. It is beneficial to cotton growth and development. (2)Sea-ice water irrigation could obviously increase soil salinity more than well water irrigation on cotton growth prophase, especially the sea-ice water flood irrigation increased most. After rainy season, soil salinity leaching seriously by rainfall. There was little difference between Sea-ice water irrigation and well water irrigation treatments in soil salinity after flowering stage. The results showed that the salt concentration is 3 g/L sea-ice water irrigation with flood irrigation or drip irrigation under mulch can't lead to noticeable salt accumulation after one growing season.3. The effect of salt ions and salt accumulation rate under sea-ice water irrigation: (1) Sea-ice water irrigation take Na+, Cl-, K+, Ca2+, Mg2+, SO42- etc. into the cotton field soil. Every salt ion increases with increasing salinity density and different irrigation number of times. Content of Na+, Cl- and K+ higher than initial value after one growing season, but Ca2+, Mg2+, SO42- lower than initial value. (2)Using the salt concentration≤5g/L sea-ice water irrigation didn't causing salification on the soil surface. The salt concentration of 1 g/L, 3 g/L and 5 g/L sea-ice water irrigation treatments soil are desalination.The desalination rate are 57.22%, 3.28% and 18.34% respectively. On the same salt concentration situation, that salt accumulation rate reduce with increasing irrigation number of times. Looking from the soil vertical profile, salt accumulation rate increases with soil depths. Salt concentration≤7 g/L and 9g/L sea-ice water irrigation treatments salt deposit seriously. In conclusion, using the salt concentration≤5 g/L sea-ice water is safety.4. The effect of cotton yield and fiber quality under sea-ice water irrigation: (1) The yield, boll number per plant and cotton boll weight were the most in c-1 treatment.The seed cotton yield reached 4186 kg/hm2. It could more increase than CK yield by 1166 kg/hm2, about 38.63%.The second one is b-3, that increase yield by 29.8%. The seed cotton yield presents a decreasing trend with salinity density increasing. Salt concentration≤7 g/L treatments had not yield reduction, but c-9 treatment compare with CK had significantly yield reduction, the yield reduction rate reached 28.48%. Boll number and cotton boll weight had the same changing rule. (2) The irrigation modes of drip irrigation under mulch could significantly increased boll number per plant and cotton boll weight compared with CK,so it could significantly improve seed cotton yield and WUE. The yield increased by 22%. Well water treatment yield more than sea-ice water, but every index didn't have significant differences. The fiber quality was no obvious difference except cotton fibre specific breaking strength. (3)Increasing irrigation number of times and salinity density could decrease cotton fiber quality,but had no significant influence. Every quality index in lower level when salt concentration 9 g/L of sea-ice water.5. Sea-ice water secure and efficient irrigation index and supporting measures: The study for the indexes of secure and efficient irrigation and put forward a set of sea-ice water secure and efficient irrigation supporting measures. The best sea-ice water irrigation institution is b-3(before seedtime and at seedling stage). Flood irrigation amount was 450 m3/hm2 each time, drip irrigation under mulch amount was 225 m3/hm2 each time. Adopting drip irrigation under mulch was beneficial to improve WUE, cotton yield and fiber quality. Adopting sea-ice water irrigation must matching irrigation and drainage, tillage, fertilization measures, such as construction of platform field, soil preparation, basal dressing and irrigation before seedtime, using saline soil amendment, mulch sowing technology, pest management and so on.
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