黄土高原典型草原群落结构和土壤水分对划破的响应

划破是草原改良的基础措施之一,划破强度是划破措施的关键环节,划破对草原健康持续管理有重要意义。目前的研究主要集中在划破对植物群落结构和生产力的影响上,然而草原植物群落与土壤水分对划破强度的响应尚不清楚。在黄土高原典型草原开展不同程度的草地划破试验,探究不同划破强度（27.4%、46.3%和61.9%）对草地植物群落物种多样性、生物量和土壤水分的影响。结果表明：3个划破强度下划破带物种丰富度显著低于未划破带1-3种/m²,划破带和未划破带群落相似性分别低于整区23.85%-119.23%和44.43%-84.55%。地上生物量随物种丰富度的增加而增大,且地上生物量与Simpson指数和Shannon Weiner指数显著负相关。3个划破强度下未划破带地下生物量和总生物量分别高于划破带88.2%-134.6%、52.4%-67.8%、2.5%-16.6%和103.9%-152.9%、59.3%-75.8%、9.1%-22.6%。植物群落物种丰富度和地上生物量随划破强度的增加呈"驼峰"型曲线变化,当划破强度分别为43.7%-55.3%和43.8%-45.7%时,植物群落物种丰富度和生物量均最高。本试验阐明了划破对典型草原植物群落特征和土壤水分的作用机制,研究结果为采用划破措施实现草地培育和草原修复提供了科学依据,对保护草地生物多样性和提高生产力具有重要意义。

Responses of plant community and soil moisture to ripping intensity in the typical steppe of the Loess Plateau of China

Ripping is one of the basic measures for grassland improvement, and its intensity a key link in the process. Ripping is greatly significance for the sustainable management of grassland sustainability. The available studies have mainly focused on the impacts of the ripping on the plant community structure and productivity, while the response of plant community and soil moisture to the ripped intensity is still unclear. In order to explore the impact of the intensity of grassland ripped (27.4%, 46.3% and 61.9%) on the species richness, biomass and soil moisture of plant community, grassland ripped experiments were carried out in the typical steppe of the Loess Plateau. The results showed that the ripped intensity significantly affected the biomass of the plant community, species richness and soil moisture. The species richness of the ripped belt was significantly lower than that of the unripped belt by 1-3 species/m² under three ripped intensities. Compared with the whole area, the similarity of plant community in the ripped belt was lower by 23.85%-119.23%, while the unripped belt was lower by 44.43-84.55%. The aboveground biomass (AGB) of the ripped belt, unripped belt and whole area all increased with the increase of species richness and aboveground biomass was negatively correlated with Simpson index and Shannon Weiner index. When the ripped intensity was 27.4% and 61.9%, the AGB of the ripped belt and the unripped belt decreased with the increase of soil moisture. The belowground biomass (BGB) and total biomass of each ripped intensity were significantly negatively correlated with soil moisture. The BGB of the unripped belt under three ripped intensities was 88.2%-134.6%, 52.4%-67.8% and 2.5%-16.6% higher than that of the ripped belt, respectively. The biomass was 103.9%-152.9%, 59.3%-75.8% and 9.1%-22.6% higher than that of the ripped belt. The species richness and AGB of the plant community first increased and then decreased with the increase of the ripping intensity. When the ripping intensity was 43.7%-55.3% and 43.8%-45.7%, the species richness and biomass of the plant community reached the highest. The species richness, community similarity index, root-to shoot ratio and other indicators of the community were integrated to analyze the impact of ripped intensity on plant community diversity, biomass and soil moisture, and clarified the impact rule and mechanism of ripped on the characteristics of typical steppe plant community and soil moisture in this experiment. The results provide a scientific basis for the adoption of ripped measures to achieve grassland cultivation and restoration, and is of great significance for protecting grassland biodiversity and improving grassland productivity.