| Because of the topography, hydrogeology and climate in inland area, there are numerous saline-alkali soil in Datong basin. It is so difficult to use these fields that agriculture in Datong basin cannot get rapid development. Drip irrigation is partial irrigation which is efficient to use water, and its low flow and high frequency guarantee high moisture in soils around root of plant which obviously improves the habitat of crop in saline-alkali soil. So it is suitable to irrigate crop on saline-alkali soil, and gets more and more research and application.The experiment of drip irrigation I did in Shuozhou is for ameliorating saline-alkali soil and improving the product of crop. The experiment includes two parts.To grasp the influence of saline-alkali soil on seed emergence and the way to improve seed emergence, the seed emergence in different grass seed varieties(lyme grass, sweet clover and alfalfa), soils(p H 10.03, 9.36, 8.68, 8.12 and EC 2.02, 1.237, 0.962, 0.454 mS/cm), sowing depths(1, 3 cm) and seed treatments(sun-cure and soaking treatment and untreated) was studied by laboratory test.The field experiment was to find out the influence of irrigation quantity(40%, 60% of evaporation) and frequency(3day, 6day)on growing of alfalfa and movement of water and salt in soil. It contributes to build better irrigation system and is useful for improving the production of alfalfa.(1)The results of laboratory test showed that lyme grass had the best salinealkaline resistance and sweet clover had the worst; the increase of pH and EC could cause the increase of seed emergence time and the reduce of seed emergence rate(pH>8.68 and EC>0.962 mS/cm); compared with the sowing depth of 3 cm, the sowing depth of 1 cm could significantly reduce seed emergence time and increase seed emergence rate; sun-cure and soaking treatment could significantly reduce seed emergence time and increase seed emergence rate.(2) The conclusions of field experiment went as following:a. Under drip irrigation, crop cultivation could regulate the distribution of water and salt in soil, so that alfalfa got better growing. During the irrigation interval, the moisture of surface soil got much decline because of evaporation, so the water in deeper soil moved up, and then water in soil was supplemented by the irrigation; the salinity of soil was dependent on the change of water in soil.b. The more quantity and the lower frequency in irrigation made larger wetting range, higher moisture content and less salinity.c. The water consumption of alfalfa increased first and then decreased, it depended on irrigation quantity and growing periods. The more quantity and the lower frequency made higher plant height, water-use efficiency and more products.d. The best irrigation system in experiment was that dripper discharge was 0.5 L/h, irrigation quantity was 60% of evaporation, and irrigation frequency was three day in seedling stage, six day in branch bud stage. |
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