【作者】 张建锋；

【导师】 彭镇华；

【作者基本信息】 中国林业科学研究院 ， 林学， 2005， 博士

【摘要】 地(G)的土壤含盐量比较高，而营养水平、土壤酶活性也比较高。灌木林地(S)的土壤含盐量比较高，而营养水平、土壤酶活性却比较低，属于立地条件较差的地块。与盐碱荒地(U)相比，它的含盐量降低不少，而营养水平、土壤酶活性也有所改善，说明通过栽植耐盐树木，提高植被覆盖率来改良盐碱荒地是可行的。林地(F和MF)的调查结果进一步说明了这一问题。林地(F和MF)的土壤含盐量比较低，营养水平、土壤酶活性比较高。还可以看出，刺槐与紫穗槐混交林的效果很好，一方面是它们都有一定的耐盐性，另一方面，都是固氮植物，能够自我积累营养。 黄河三角洲地区有种子植物189种，隶属40科120属；另外，还有蕨类植物3科3属4种。植被主要包括人工植被和天然植被两种类型，其中，人工植被以刺槐林为主，约1万hm~2；天然植被主要有湿生植被和盐生植被两种植类型，包括10余种群落。黄河三角洲植物群落演替的过程实质上就是生境地下水埋深和土壤盐分的变化过程，换言之，地下水埋深和土壤盐分是黄河三角洲植物群落演替的两个主要生态因素。 在黄河三角洲地区，每年都有新的陆地形成。新生陆地有不同的利用方式。为了探讨林业利用的效果，选择典型新生陆地营造了混交林。20年后调查发现，混交林能有效降低土壤含盐量，防止土壤返盐退化。综合不同模式林分对土壤的抑盐效果、养分及有机质含量、对组分树种的生长和林地生产力的影响，发现以刺槐为目的树种可选择隔行与白蜡株间混交，其它混交林可选择刺槐为伴生树种，但混交方式和混交比例应有所不同；白榆刺槐混交宜选择5：5行带状混交或隔两行隔株混交；臭椿刺槐混交宜选择1：1行间混交；以杨树为目的树种可选择与刺槐1：1行间混交，行间种植紫穗槐；白蜡与刺槐行状混交效果也较好。 黄河三角洲地区还有大面积的湿地。本文还对湿地生态系统面临的主要问题及生态修复措施进行了讨论。更多还原

【Abstract】 Based on the project conduction of China Forest Eco-nets System Research and former work foundations, the topic of land degradation mechanism and ecological rehabilitation techniques in Yellow River Delta (YRD) region was chosen as the postdoctoral report.Land degradation was defined that land quality and productivity decline due to adverse natural factors in addition to irrational land use. Thus land degradation behaved that land bio-product reduction, potential production decrease, land resources lose and production conditions worsening. It referred with soil erosion, desertification, salinization, leanness, acidification, swamp and pollution, etc. In another word, it could be concluded that soil physical degradation, chemical degradation and biological degradation. In this report the problems concerned with land degradation such as desertification, soil & water erosion, salinization, mine abandon land, soil & water erosion in dry valley area, road construction were discussed.According to statistics, there was 2.0 × 10~9 km~2 degraded land on the earth, while soil & water erosion area was 2.642 ×10~7 km~2, which took 28.3% of the whole world farmland. In China there was soil & water erosion area 3.56×10~6 km~2, which took 37.1% of the total land area up to 2002. By 2004, there was desertification area 1.74 ×10~6 km~2 in the country. In view of some relative research results driving factors of land degradation were analyzed as well. Thereby combating measures mainly concerning ecological rehabilitation techniques were put forward.YRD lied at Bohai sea gulf, was one of the three biggest deltas in the country. Total land area covered 12000 km~2, while averagely 0.5hm~2 per capita, arable land was 0.19hm~2 per capita in the region. As well known that the region was alleviated, so that its natural resources were rich. However here rainfall was less, mineral content in更多还原