Nature Environment and Pollution Technology

Ruiping Hou ¹, Kebin Zhang ¹, Bilal Ahmad ¹, Lili Wang ¹, Xiao Wang ¹

Affiliations
1 School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, CN

Abstract

A pilot study of hydrological effects of litter and soil layers was carried out on different density plantations of Pinus sylvestris L. Var. mongolica Litv. in the southeast of Mu Us Sandland. For the purpose of evaluating the hydrological function of litter and soil quantitatively, 30 standard plots (10 types of forest×3 replications) were investigated. The soil physical characteristics and water-holding capacity were determined. The results showed that: (1) The total storage capacity of litter among 10 forest types, generally followed by the sequence of forest densities, were P_III = P_IV > P_X > P_VII > P_IX > P_VI > P_VII > P_V > P_II > P_I; the maximum water-holding capacity and effective water-holding capacity of litter, for 10 forest types, were 2.46-8.23 t/hm² and 0.163-6.42 t/hm², respectively. (2) There were no significant differences in water content, bulk density and the maximum water-holding capacity of soil amongst these forest types, with the variation range of 8.94-16.54%, 1.10-1.66 g/cm³ and 200.43-266.43 t/hm², respectively. However, the non-pore porosity of soil among these 10 forest types varied greatly with a variation range of 0.99-4.32%. The hydrological effects of soil were the highest in the P_III and P_IV plots, and the lowest in the P_I plot. (3) The power function model can better indicate high correlation coefficients between the water absorption rate of litter and its immersion time, and also between the water-holding capacity of litter and its soaking time. The stable infiltration rates of soil in 10 different forest stands were consistent, while they varied greatly with a range of 0.11-0.89 mm/min after 20 minutes. (4) In this study, the hydrological effects of forest litter and soil in P_III and P_IV plots were the best, and the optimal afforestation density was 1500 to 1800 plants per hectare. The results show that thinning should be done timely and appropriately in this study area to prevent the recession of a forest stand. Besides, it is unapproachable whether Pinus sylvestris Var. mongolica can be planted in large scale or in high density, and further research is needed.

Keywords

Forest Litter, Water-Holding Capacity, Hydrological Effect, Pinus sylvesiris L. Var., Mongolica Litv.

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Lili Wang ¹, Kebin Zhang ¹, Ruiping Hou ¹, Xiaoteng Xu ¹, Xiao Wang ¹, Xiaodan Liu ¹

Affiliations
1 School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, CN

Abstract

Fencing has been used as a main measure for rangeland and pasture rehabilitation all over the world. By quadrat method, the vegetation of Yanchi County of Ningxia Hui Autonomous Region has been investigated for the impacts of different fencing time on vegetation community structure and biomass. The result shows that it increases biodiversity and makes the vegetation community more stable. But long time fencing is not conducive to vegetation recovery. The Biodiversity Index in the edge areas and peripheral areas reached to highest level in the 4^th and 5^th year after fencing respectively. The Richness Index (R₁) and Comprehensive Diversity Index (D, H) of the edge areas are 22, 2.26, 6.18, and those in the peripheral areas reach to 13, 1.67 and 3.24. Then biodiversity index decreased as fencing time increases. Under different fencing measures, the Biodiversity Index in the core area is the highest. So fencing is an effective measure for vegetation restoration. The vegetation coverage and biomass in the peripheral areas are the largest. This shows that rational uses of grassland are beneficial to vegetation recovery. Strip tillage doesn't have obvious effects on vegetation recovery, and it suggested that grazing or cutting can be used in this region for rangeland and pasture rehabilitation.

Keywords

Fencing Time, Exclusion Measures, Biodiversity, Sandy Rangeland, Semi-Arid Area.

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