黄土丘陵区典型植被类型草本层生态学特性与环境解释

在野外调查的基础上研究黄土丘陵区4种典型植被类型（达乌里胡枝子群落、白羊草群落、人工刺槐林、人工柠条林）草本层生态学特性，通过室内土壤养分和水分含量测定分析群落间环境因子的差异，并对群生态学指标和环境因子进行相关分析。研究结果表明:（1）豆科、禾本科、菊科植物重要值在4种群落中均很高，群落间各科物种重要值差异显著。（2）群落物种多样性表现为:人工刺槐林 > 人工柠条林 > 达乌里胡枝子群落 > 白羊草群落；群落盖度表现为人工刺槐林 > 白羊草群落 > 达乌里胡枝子群落 > 人工柠条林；草本群落地上生物量表现为:白羊草群落 > 人工刺槐林 > 达乌里胡枝子群落 > 人工柠条林。（3）土壤有机质、全氮、速效氮和速效钾含量表现为:工刺槐林 > 白羊草群落 > 达乌里胡枝子群落 > 人工刺槐林，达乌里胡枝子群落和白羊草群落土壤全磷、速效磷含量较高。（4）土壤水分含量表现为:白羊草群落（8.43%） > 达乌里胡枝子群落（7.60%） > 人工柠条林（6.43%） > 人工刺槐林（5.85%）。（5）群落盖度、草本群落地上生物量与土壤养分指标正相关，物种多样性与土壤养分的关系相对复杂；群落盖度及物种多样性均与土壤水分含量负相关，草本群落地上生物量与土壤水分含量相关性不显著。

Biological Characteristic and Its Environmental Interpretation of Herbosa Under the Typical Vegetation Types in Loess Hilly Region

Community biological characteristics of herbosa under four typical vegetation types (Lespedeza daurica community, LDC; Bothriochloa ischaemum community, BIC; planted locust forest, ALF; planted caragana stand, ACS) were studied based on field investigation, environmental factors of each community were analyzed by measuring soil nutrient and moisture content, and analysis on correlation between biological indexes and environmental factors was carried out. The results were shown as the followings. (1) Important values of Leguminosae, Gramineae and Compositae plants are quite high in four communities, and significant differences existed in each family between four communities. (2) Species diversity showed the sequence: ALF > ACS > LDC > BIC; community coverage showed the order: ALF > BIC > LDC > ACS; above-ground biomass of herb showed the order: BIC > ALF > ACS > LDC. (3) Contents of soil organic matter, total nitrogen, available nitrogen and available potassium showed the order: ALF > BIC > LDC > ACS, higher contents of soil total phosphorus, available phosphorus were observed under BIC and LDC. (4) Soil moisture content showed the order: BIC(8.43%) > LDC(7.60%) > ACS (6.43%) > ALF(5.85%). (5) Positive correlation between community coverage, above-ground biomass and soil nutrient was found, relationship between species diversity and soil nutrient was complicated. Both community coverage and species diversity were negatively correlated with soil moisture content. Correlation between above-ground biomass and soil moisture was not significant.