土地利用方式对喀斯特地区环境小气候日动态的影响

2007年6月，通过典型样地观测，研究了广西凌云县典型喀斯特地区5种不同土地利用方式下光照强度、气温、空气相对湿度、土壤温度、表层（0～5 cm土层）土壤含水量的日动态.结果表明：不同土地利用方式改变了地上植被的组成、覆盖度和高度，进而改变了环境小气候，研究区不同土地利用方式的小气候质量依次为林地＞灌林＞草地＞农耕地＞石漠化裸地; 石漠化裸地光照强度较强、气温和土壤温度较高、空气相对湿度和土壤含水量较低，且各因子的变幅均较大，样地环境趋于干热化;与石漠化裸地相比，林地、灌林地、草地和农耕地内的光照强度分别下降96.4%、52.0%、17.0%和44.2%，气温分别下降30.1%、20.2%、12.7%和17.8%，空气相对湿度分别提高129.2%、57.2%、18.0%和41.2%，土壤温度分别下降11.5%、8%、2.5%和5.5%，表层土壤含水量分别提高42.6%、33.2%、15.7%和14.0%，林地与灌林地各因子的变幅相对趋缓，样地环境趋于凉湿化.各样地光照强度、气温和土壤温度之间呈正相关，三者均与空气相对湿度、土壤含水量呈负相关，空气相对湿度与表层土壤含水量呈正相关.

Effects of land use type on diurnal dynamics of environment microclimate in Karst zone.

In June 2007, the diurnal dynamics of light intensity, air temperature , air relative humidity, soil temperature, and surface soil (0〖KG-*2〗-〖KG-*7 〗5 cm) water content of five land use types in the typical Karst zone of Lingyu n City in Guangxi Zhuang Autonomous Region were observed. The results showed tha t different land use types altered the composition, coverage, and height of abov eground vegetation, which in turn changed the environment microclimate to differ ent degree. The microclimate quality was in the order of forestland>shrub land>g rassland>farmland>rock land. On rock land, the light intensity, air temperature, air relative humidity, soil temperature, and soil water content were higher, an d the diurnal variation of the five climatic factors was notable, with the micro climatic conditions changed towards drier and hotter. Compared with those on roc k land, the light intensity on forestland, shrub land, grassland, and farmland d ecreased by 964%, 520%, 170% and 442%, air temperature decreased by 30 1%, 202%, 127% and 178%, air relative humidity increased by 1292%, 572 %, 180% and 412%, soil temperature decreased by 115%, 8%, 25% and 55%, and soil water content increased by 426%, 332%, 157% and 140%, respecti vely. The five climatic factors on forestland and shrub land had lesser fluctuat ion, with the microclimate tended to cool and wet. Light intensity, air temperat ure, and soil temperature correlated positively with each other, and had negativ e correlations with air relative humidity and soil water content. A positive cor relation was observed between air temperature and soil water content.