辽河三角洲盐碱地不同造林模式的防护效应研究

Protective Effects of Shelterbelts of the Different Allocation Mode in the Saline-alkali Soil of Liaohe River Delta

为了研究不同造林模式对盐碱地的土壤改良及防护效应,选取辽河三角洲盐碱地11块典型防护林,测定林地内环境因子、土壤物理性质、土壤含盐量,并对林内外草本生物多样性进行统计.结果表明：不同造林模式的防护林在夏季均能起到改善小气候的作用,其中可降低林内空气温度2.2℃,提高林内空气湿度10.2％,降低林带背风面风速1.3 m·s-1,且混交林对小气候的改善程度高于纯林,其中白榆刺槐混交林可降温达3.7℃,增加湿度25.3％,改善温湿度效果最明显,其次是白蜡刺槐混交林,小胡杨纯林改善温度效果最不明显,仅能降低林内温度1.1℃;混交林能明显降低0～40cm土层的密度和增加土壤孔隙度,而纯林改善土壤孔隙度效果不显著;不同防护林均能降低盐碱地的土壤含盐量,混交林降低幅度在60％～88％之间,可以将重度盐碱地改良为轻盐碱地,除刺槐纯林外,其他纯林改良盐碱地效果不显著;防护林还可显著增加林内草本多样性.在盐碱地上营造混交型防护林防护效应较明显,11种造林模式中白蜡刺槐混交林和白榆刺槐混交林效果最好,白蜡沙枣和白蜡小胡杨次之.

The protective effects of shelterbelts of the different allocation were studied through determining microclimate factors, soil physical properties, salinity and forest plant diversity were determined in 11 typical protective forests in Liaohe River Delta. The results showed that shelterbelt played the role of improving the microclimate in the summer,and the effect of mixed forest was higher than that of the pure forest,which reduced the air temperature of 2.2℃,and increased the air humidity of 10.2%, and reduced the shelterbelt leeward wind speed of 1.3m·s^-1. The effect of Ulmus. pumila and Robinia~ pseudoacacia mixed platation （URMP） on temperature and humidity was best, then Fraxinus. chinensis and R. pseudoacacia mixed platation （FRMP）. Mixed forest could improve significantly 0-40cm soil density and porosity; pure forests could only improve unremarkably soil porosity. Shelterbelt could reduce soil salt content, mixed forest decreased in the range of 60%-88%, soil salt content reduced cut to 3%o（light salinity） or less. The effect of pure forest on reducing soil salt content was little. Improvement of plant diversity was significant in protective forest. The protection of the mixed plantation is better than the pure plantation in the saline-alkaline. URMP and FRMP are the best among the 1 l typical protective forests.