宁南黄土丘陵区典型草原土壤性状对地表扰动植被恢复的响应

Soil is the existent base of grassland vegetation, and changes of soil properties can bring on changes of vegetation. Typical steppe in hilly area of the Loess Plateau is the important herd base and ecological barrier in the south of Ningxia. Land surface layer disturbed measures in large aere, such as parallel ditches and fish-scale pits, change soil properties and influence vegetation restoration. Therefore, studies on influence effects of land surface layer disturbed restoration measures on soil properties in typical steppe in hilly area of the Loess Plateau is of important significance to vegetation restoration in this area. In order to discuss the responses of soil properties to land surface layer disturbed vegetation restoration in typical steppe in hilly area of the Loess Plateau, the main ecological restoration measures including being ungrazed, parallel ditches and fish-scale pits of different ages will be selected as studying objects. The soil physicochemical and biological characters, characteristic of soil seed bank and plant communities under three restoration measures will be studied by some theories and methods of grassland ecology and restoration ecology. The interrelation of vegetation characters，soil seed bank and soil characteristics will be discussed. The influence of soil properties change on vegetation succession will be illuminated. The influence effects and mechanism of land surface layer disturbed vegetation restoration measures on soil properties in typical steppe in hilly area of the Loess Plateau will be revealed, and ecological restoration effect of three measures named being ungrazed, parallel ditches and fish-scale pits will be estimated. The aim of these studies could provide theory evidence for grassland ecological construction in hilly area of the Loess Plateau.

土壤是草地植物赖以生存的基础，其性状的改变会导致植被变化。作为宁夏重要牧业基地和生态屏障的宁南黄土丘陵区典型草原，在生态恢复中大面积采用的开挖水平沟和鱼鳞坑等地表扰动方式改变了草原土壤性状，影响了植被的恢复。因此研究地表扰动恢复措施对黄土丘陵区草原土壤性状影响效应对该区进行植被恢复具有重要意义。为了探讨黄土丘陵区典型草原土壤性状对地表扰动植被恢复的响应，本项目拟以宁夏黄土丘陵区典型草原不同实施年限的封育、水平沟和鱼鳞坑三种主要人工恢复措施为研究对象，采用草地生态学和恢复生态学的理论和方法，研究不同恢复措施影响下的土壤理化性质、生物学性状、土壤种子库和草地植物群落特征，探讨土壤性状、土壤种子库和植被特征间相互关系，阐明土壤性状变化对植被演替的影响，揭示地表扰动植被恢复措施对典型草原土壤性状的影响效应及机理，评价封育、水平沟和鱼鳞坑措施的生态恢复效果，为黄土丘陵区草原生态建设提供理论依据。

宁南黄土丘陵区典型草原是宁夏重要牧业基地和生态屏障，该区在生态恢复中大面积采用的封育、水平沟和鱼鳞坑措施改变了草原土壤性状，研究这些措施对土壤性状影响效应对该区植被恢复具有重要意义。. 项目以宁夏黄土丘陵区典型草原封育、水平沟和鱼鳞坑三种生态恢复措施实施0年（1年）、3年、6年、10年和15年的草地为对象，通过调查测定，比较了各措施影响下的土壤理化生物学性状、种子库和草地植被特征，探讨了土壤性状、种子库和植被间相互关系，评价了各措施生态恢复效果。结果表明：各措施下植物群落可划分为8个类型，群落演替序列各异、处在不稳定的演替阶段。随恢复年限延长，封育草地植被盖度、高度及地上生物量增加，水平沟和鱼鳞坑盖度呈上升趋势。封育草地植被盖度、高度及地上生物量最高，但物种丰富度、多样性、均匀度指数下降。植物种群多为聚集分布，生态位重叠系数呈鱼鳞坑＞水平沟＞封育。水平沟和鱼鳞坑土壤粘粒比例高于封育，鱼鳞坑土壤容重最高。封育草地土壤水稳性团聚体及其破坏率最低，但土壤有机质等养分最高。土壤有机碳及全氮储量呈封育>鱼鳞坑>水平沟。土壤微生物总量、放线菌和真菌数量、量碳量氮含量、蔗糖酶、蛋白酶等活性在封育草地较高。土壤质量表现为封育>水平沟>鱼鳞坑。鱼鳞坑、水平沟和封育均可提高土壤种子库植物种数和种子库密度，种子库和地上植被的相似性较低。土壤容重、有机质、速效氮、全氮、微生物总量与植被盖度、生物量密切相关。影响该区群落分布的土壤因子主要为容重、有机质、速效氮、全磷和含水率，含水率是影响植被特征的最主要因子。研究认为，水平沟和鱼鳞坑一定程度上增加了植物物种和种子库多样性，封育有利于多年生草本物种数、盖度、地上生物量和土壤质量的增加，但长期封育降低了植被物种多样性。研究从一个较长时期探讨了封育、水平沟和鱼鳞坑地表扰动措施对草地植被和土壤性状的影响，为该区生态恢复提供了理论依据和实践指导。