Research Of Saline Soil Afforestation Technique In Coastal Argillaceous Saline-alkali Land

Afforestation in saline-alkali land is a challenging task facing many countries. The coastal argillaceous saline-alkali land which the salt content is so highly that it is not available for the seedling is one such area in China. The purpose of this paper is to research the suitable afforestation system in coastal argillaceous saline-alkali land. The water-salt dynamic of platform field with different isolation layer, the survival rate and growth of seedlings, the water-salt dynamic inside planting hole in new planting technique and conventional planting technique were determined in Nanpu Economic Development Zone, Tangshan.The soil of experimental field is easily lead to salt accumulation for the ground water line was above the critical depth. Through the platform field preparation, the salt of platform field discharged by the side. The soil conductivity decreased year by year from lOms/cm to 4ms/cm, then kept the value to a relatively stable state. The average annual soil moisture did not change significantly. There was a negative correlation between the soil water and salt. By the "up-down" process of rainfall, the soil salt showed the "down-up" while the soil moisture changed as opposite trend which is "up-down". The isolation layer was played an important role in drainage and salt resistance. The soil conductivity by different isolation way was significant while the soil conductivity by different distribution which contains slag and garbage architecture was not significant. The order of the soil conductivity by different isolation way was the "all-shop", "double-one bar" and "double bar". It was not significant by the "all-shop" and "double-one bar", so the "double-one bar" isolation layer was the best choice with the cost.The result of the moisture capacity, water absorption rate, evaporation and shape of base showed that the optimal formula of base was the volume ratio of new soil, peat, perlite and vermiculite which is 50:30:10:10, compound addition level 2.5g/base,5g/base and 7.5g/base, adhesive addition lever 0.005g/base and 0.01g/base. The seed survival rate of seed-base seeding afforestation was better than the direct seeding afforestation indicated that the base provide a well local growth environment. The best formula of seed-base was the volume ratio of new soil, peat, perlite and vermiculite which is 50:30:10:10, compound addition level 2.5 g/base. Adhesive has little effect on seed-base seeding afforestation. During the seedling growth, different compound and adhesive were not significant on survival rate and height. This is mainly because the harsh environment which contains high salt content and the wind, short woody of seed-base, combined with poor management and protection is not perfect, leading to the base could not fully play its part to improve seedling. The seed of Berberis thunbergii was the best appropriate seed for seed-base seeding afforestation technique. Though there was obvious effect in earlier afforestation period, the seed-base seeding afforestation had to dead for the harsh environmental conditions. Therefore, the seed-base seeding afforestation is not appropriate for the coastal argillaceous saline-alkali land.The survival rate and growth of seedlings, the water-salt dynamic inside planting hole in hole-film base planting afforestation technique and conventional planting afforestation technique were researched, these showed that the film can effectively prevented the infiltration of salt and reduce the evaporation, lateral roots that promote seedling roots to the shallow and lower salinity soil layers. While the matrix can conserve soil water, hole-film base planting afforestation technique which contains film and matrix can increase the survival rate and seedling growth, and is suitable for the coastal argillaceous saline-alkali land for it can provide a well environment for seedlings. Simultaneously, the Morus alba L. which is saline-alkali tolerant and high economic value is appropriate to adaptation in coastal argillaceous saline-alkali land.To sum up, the afforestation system in coastal argillaceous saline-alkali land contains platform field preparation and hole-film base planting afforestation technique. The content of new afforestation system in coastal argillaceous saline-alkali land can be summarized as platform field preparation, lining film and matrix, conserver water and resist salt, lateral root. the afforestation system in coastal argillaceous saline-alkali land is highly suitable for the use in afforestation of China's coastal argillaceous saline-alkali land, and may promote for more area for its simple and low cost. The results provide theoretical basis in afforestation and land reclamation in saline-alkali land.