Informatics Publishing Limited

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.

Full Text

   

Xiaodan Liu ¹, Kebin Zhang ¹, Mammo Siraj ¹, Lili Wang ¹

Affiliations
1 School of Soil and Water Conservation, Soil and Water Conservation Key Laboratory of Ministry of Education, Beijing Forestry University, Beijing 100083, CN

Abstract

Biocomplexity theory is becoming increasingly important in understanding natural vegetation dynamics and interrelation among all components of ecosystems. A study was conducted under this concept in order to investigate the impacts of different fencing periods and measures on plant community complexity in desert grasslands of Yanchi County of Ningxia Hui Autonomous Region. The study was carried out by using a quadrat method and based on the average length of the Huffman code to describe total complexity L(S), Rényi entropy H(S) as disorder-based complexity, and the difference D (S) = L(S)-H(S) as structural complexity. The relationship was also studied between three kinds of complexity index and the number of species, Importance value of dominant species. The results showed that enclosure increases disorder-based complexity index and structural complexity index, which makes total complexity index to increase. Therefore, fencing is an effective measure for vegetation restoration and rehabilitation while long-term fencing is not conducive to vegetation restoration. In this study disorder-based complexity index is higher than structural complexity index, which means that disorder-based complexity index has great effects on total complexity index. The relationship between L(S ) and H(S) is very close whereas the correlation between H(S) and D(S) is negative. There is significant relationship between the number of species and the three kinds of complexity index. The importance value of dominant species is not significantly correlated with structural complexity, which has significant negative correlation with the other indices.

Keywords

Fencing Period, Sandy Rangeland, Plant Community, Community Complexity, Semi-Arid Area.

Full Text

   

Xiaoteng Xu ¹, Kebin Zhang ¹, Lili Wang ¹, Zhiru Hao ¹, Victor Squires ², Li He ¹

Affiliations
1 School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, CN
2 Dryland Management Consultant, Adelaide 5892, AU

Abstract

Ten kinds of antibiotics belonging to tetracyclines, sulfonamides, quinolones and macrolides were detected in water samples from Haihe River, China. Sulfamethoxazole and sulfachlororyridazine had largest detection frequencies (100% and 86%), with the maximum concentrations of 330 ng/L and 380 ng/L, respectively. Friedman and Moran's I test indicated that the target antibiotics at different sampling sites were significantly different (p < 0.05), suggesting that the antibiotics detected in the Haihe River were primarily depended on proximal sources of antibiotics. Municipal wastewater plants, fishponds, and livestock's industries along the river were confirmed to import antibiotics to the tributaries, and then distribute into the mainstream. By studying the variations of relative compositions of antibiotics in both surface water and sediment, we found that sulfonamides had a much higher migration capacity than other antibiotics, quinolones and macrolides deposited in sediment after travelling short distance from sewage outfall and tetracyclines in pollution sources was strongly absorbed in the sediment.

Keywords

Antibiotics, Haihe River, Pollution Sources, Migration Capacity.

Full Text

   

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.

Full Text