平茬密度对荒漠草原人工柠条林间生境的影响

合理平茬对柠条林更新复壮及科学利用具有重要意义。以宁夏荒漠草原6 m带距人工柠条林(中间锦鸡儿,Caragana intermedia)林间草原为研究对象,研究了全平(QP)、隔一带平茬两带(G1P2)、隔一带平茬一带(G1P1)、隔两带平茬一带(G2P1)、未平茬(WP)五种密度(间距)平茬后柠条林间植被和土壤性状、小气候和土壤风蚀特征等变化。结果表明:(1)G2P1处理下林间植被物种总数、密度、高度和地上生物量最高,物种丰富度、多样性指数以G1P1、G2P1较高。(2)0—40 cm土壤容重以G1P1、G2P1较低,但机械组成无明显变化规律;土壤有机质、速效钾、全氮和速效氮以G2P1最高,但速效磷G1P1最高;土壤平均含水量以G2P1较高,达到8.33%,G1P2和WP最低,WP水分垂直变异系数最大。(3)处理间气温和风速无显著差异;风蚀量以QP、G1P2和WP较高,G1P1与G2P1较小。研究认为,适宜的密度平茬对人工柠条林间生境有改善作用,宁夏荒漠草原人工柠条林平茬时可采取隔两带平茬一带的方式。

Effects of different cropping densities on the habitat of artificial Caragana intermedia in desert steppe

The reasonable stubble is of great significance to the renewal, rejuvenation and scientific utilization of Caragana intermedia. Taking 6 m belt of Ningxia desert steppe from the artificial Caragana intermedia forest steppe as the research object, we studied the effects of the vegetation traits, soil physical and chemical properties, air temperature, wind speed and soil wind erosion which caused by five different management practices of stubble spacing, such as all stubble (QP), stubble two belts with one belt no stubble (G1P2), stubble one belt with one belt no stubble (G1P1), stubble one belt with two belts no stubble (G2P1), no stubble (WP). The results showed that (1) the total number, density, height and above-ground biomass of forest vegetation were the highest under G2P1, while the species richness and diversity index were higher in G1P1 and G2P1. (2) The soil bulk density of 0-40 cm is lower with G1P1 and G2P1, but the mechanical composition had no obviously change under different treatments. The soil organic matter, available potassium, total nitrogen and available nitrogen were the highest in G2P1, but available phosphorus was the highest in G1P1. From April to November, the average soil water content was higher in G2P1 with 8.33%, while it was the lowest in G1P2 and WP. The moisture of WP had the largest vertical coefficient of variation. (3) There was no significant difference in average temperature and wind speed between forests under each treatment (P > 0.05). The amount of wind erosion was higher with QP, G1P2 and WP, but it was smaller in G1P1 and G2P1. The study suggests that the appropriate density of stubble can improve the habitat of artificial Caragana intermedia. G2P1 method can be adopted when the artificial Caragana intermedia forest in Ningxia desert steppe was cutting.