Effects Of Different Land Use Types Research Articles

Mycorrhizal Types Modulate Responses of Global Soil Microbial Biomass to Environments Across Varied Land Use Types

AbstractSoil microbial biomass (SMB) is a fundamental contributor to soil ecosystem services. Mycorrhizal fungi, a significant group of soil microbes, play essential roles in regulating carbon allocation and nutrient cycles. Acknowledging the profound importance of SMB and mycorrhizal symbiosis, our objective was to explore how mycorrhizal types modulate the global patterns of SMB across varied land use types (LUTs). Using data from 329 independent studies, we categorized vegetation species with defined mycorrhizal types into arbuscular mycorrhizal (AM) type (with 958 observations) or mixed AM and ectomycorrhizal (AM + ECM) type (with 481 observations). This categorization served as the foundation for our investigation into the impacts of various LUTs and environmental conditions (mean annual temperature, and mean annual precipitation, MAP) on global SMB patterns associated with specific mycorrhizal associations. The overall mean value of SMB was remarkably higher under AM + ECM type (92.23 ± 4.73 nmol/g) compared with that under AM type (49.45 ± 1.87 nmol/g) at a global scale. The primary factor contributing to this difference was the natural system. Additionally, the AM + ECM type (0.19 ± 0.01) exhibited a higher F:B ratio (Fungi‐to‐bacteria ratio) than the AM type (0.16 ± 0.001), attributed to the cumulative effects of different LUTs. Furthermore, SMB was markedly positively affected by aridity index under AM type and negatively influenced by temperature under AM + ECM type. Besides, MAP had a pronounced positive impact on SMB under AM type, while exhibiting a negative impact under AM + ECM type. Our study presented evidence affirming the essential role of mycorrhizal associations in shaping global patterns of SMB in response to environmental factors across varied LUTs.

Effects of different land-use types on the activity and community of autotrophic microbes in karst soil

CO2 fixation by soil autotrophic microbes could make considerable contribution to soil organic matter (SOM). However, the effects of different land-use types on the activity and community of soil autotrophic microbes are still unclear. In this study, the autotrophic carbon fixation (ACF) rates of karst soils with four land-use types were assessed by 13CO2 labelling. After 21 days incubation under alternate 12 h light with darkness, the ACF rate was 0.18 mg C·kg-1·day-1 in bare land soil, approximately 0.39 mg C·kg-1·day-1 in crop land and shrub land soils, while sharply increased to 1.54 mg C·kg−1·day−1 in grass land soil. The 13C nuclear magnetic resonance analysis of SOM showed that the fixed 13CO2 was mainly incorporated into carbonyl carbon in grass land soil, but largely incorporated into recalcitrant aromatic carbon in other land-use types, especially in bare land. Longer incubation time (21 days versus 7 days) greatly elevated ACF rate only in grass land soil (by about 4 times) under continuous light conditions, suggesting that longer incubation in light conditions largely stimulated microbial phototrophic CO2 fixation in grass land soil. Metagenomic analysis showed that the soil autotrophic microbial communities were prominently different among the four land-use types, and the autotrophic populations using bicarbonate as inorganic carbon species were most important for explaining the variations of autotrophic communities among the land-use types. Additionally, total nitrogen and soil organic carbon contents could be the key controlling factors of both ACF rates and structure of autotrophic microbial communities. Eventually, the change of soil properties caused by land-use type substantially affected the activity and community of soil autotrophic microbes, as well as the fate and stability of the assimilated CO2.

Seasonal Dynamics of Soil Enzymatic Activity under Different Land-Use Types in Rocky Mountainous Region of North China

To reveal the effects of different land-use types on soil enzyme activities, soil samples were collected from 0–10, 10–20 and 20–30 cm soil layers to compare and analyze soil β-glucosidase (BG), urease (URE), protease (PROT) and catalase (CAT) activities in farmland (FL), abandoned land (AL) and three plantation forests: Platycladus orientalis (L.) Franco (PO), Robinia pseudoacacia L. (RP) and Quercus variabilis Bl. (QV) in the rocky mountainous region of North China. The results showed that the soil enzyme activities varied significantly under different land-use types, and the interannual mean values of FL and PO were remarkably higher than those of other land uses in the 0–30 cm soil layer, in which the soil BG and URE activities of FL were 22% and 12% higher than those of AL, and 428% and 179% higher than those of QV, respectively; the soil PROT and CAT activities of PO were 66% and 23% higher than those of AL, and 479% and 113% higher than those of QV, respectively. Soil BG, URE and PROT activities were all higher in June and lower in December, while soil CAT activity was slightly lower in June. The soil enzymatic activities all showed a notable decrease with the depth of the soil layer. Soil BG, URE, PROT and CAT activities were remarkably (p < 0.01) or significantly (p < 0.05) positively correlated with available nitrogen, available phosphorus, available potassium, dissolved organic carbon (DOC), NO3−-N, soil organic carbon, water content, clay and silt volume fraction, and significantly negatively correlated with sand volume fraction. Soil DOC and pH were important factors influencing soil enzymatic activity, implying that changes in soil enzymatic activity under different land-use types may be the result of a combination of temperature, moisture and plant type. In conclusion, PO plantations are conducive to improving the physicochemical and biological properties of soil and enhance soil fertility, which is a reasonable land-use method to achieve sustainable development in the rocky mountainous region of North China.

Responses of soil aggregate stability to organic C and total N as controlled by land-use type in a region of south China affected by sheet erosion

Soil aggregate stability is considered as one of the most sensitive parameters that reflect soil structure and quality, which is significantly influenced by soil organic carbon (OC) and total nitrogen (TN). However, the responses of soil OC and TN contents in both bulk soils and aggregates to aggregate stability as affected by land-uses remain unclear, especially under sheet erosion condition. Thus, aiming to investigate the effects of different land-use types on soil aggregate stability, aggregate-associated OC and TN contents and the relationships between them under sheet erosion condition in south subtropical zone of China, soil samples from four land-use types were collected at soil depths of 0–10, 10–20 and 20–30 cm, respectively. Results showed that soil water-stable aggregate content (WSA), mean weighted diameter (MWD), geometric mean diameter (GMD), aggregate-associated OC and TN were highest in woodland soil and showed significant differences among different land-use types (P < 0.05), which were mainly because of the differences on aggregate size distributions induced by soil erosion. Soil aggregate-associated OC and TN contents decreased with the increases of aggregate sizes. In addition, soil aggregate-associated OC and TN contents were negatively correlated with aggregate sizes, because of the strong bonding ability among OC, TN, clay particles and aggregates. Moreover, the interactions among soil aggregate-associated OC, TN and physicochemical properties contributed to 81.7 % of aggregate stability, which highlighted the vital role of OC and TN on maintaining soil aggregate stability under sheet erosion condition. Therefore, appropriate agricultural and engineering strategies focusing on the enhancement of aggregate-associated OC and TN should be carried out to maintain soil aggregate stability and reduce erodibility under global sheet erosion condition.

Effect of Different Land-Use Types on Soil Properties in Cheha District, South-Central Ethiopia

Land-use changes under poor management practices are among the major causes of decline in soil fertility and agricultural productivity in south-central Ethiopia. Therefore, the study of soil properties variations across land-use types will have implications for planning proper soil management strategies. This study assessed the effects of land-use types on soil physicochemical properties in the Cheha district, south-central Ethiopia. Seven land-use types, eucalyptus plantation, cultivated, grazing, shrub, enset (Ensete ventricosum), khat (Chata edulis), and natural forest, were considered in describing soil fertility. A total of 21 soil samples (0–20 cm depth) were collected randomly from three representative soil sampling plots across each land-use type and examined for their analysis of soil physicochemical properties. Results showed that land-use changes induced significant (p &lt; 0.05) differences in the soil OC, total N, CEC, pH, aluminum saturation, and Fe among land-use types were observed. Soils under eucalyptus plantation were considerably low in the sand (23.44%), silt (24.00%), and available water content (111.13 mm/m), whereas high in clay (52.56%) content and bulk density (1.39 g cm−3) as compared to enset land-use type. Compared to natural forest, soils under enset land-use type were high in soil OC (2.41%), total N (0.23%), and CEC (37.61 cmol (+) kg−1) followed by khat land-use. Correlation analysis also showed a highly significant positive relationship between soil OC and CEC but negative with bulk density, soil pH, and aluminum saturation. Total N in eucalyptus plantation, cultivated, khat, and enset lands were depleted by 56.0%, 40.0%, 36.0%, and 8.0%, respectively. Relative to forest land, lower exchangeable Ca, Mg, and Na contents were recorded in soils of cultivated land use. The extractable Fe, Mn, and Zn contents of soils were generally high and are not limiting for crop production. The intensive exploitation of land resources and improper soil management systems in the area could be the major factors for variations in soil properties across land-use types. Therefore, there is a need to develop integrated soil management practices that could help to restore soil nutrients and thereby minimize the continuing soil degradation for sustainable agricultural productivity.

Soil Chemical Properties under Various Land-Use Types in the Karst Area with a Case Study in Shibing County of China

The effects of different land-use types on the pH, organic carbon, total nutrient, and available nutrients of soil in the 0–30 cm and 30–60 cm layers were studied using the gray relational analysis method. The research area is located in Baiduo village in the dolomite karst region and Shiqiao village in the limestone karst region of Shibing County, Guizhou Province, China. The land-use types investigated included shrubland, forest, grass slope, dryland, paddy field, pear orchard, and flue-cured tobacco field. The contents of organic carbon, total nitrogen, alkaline hydrolysable nitrogen, and available potassium, as well as the pH of the soil in the dolomite shrubland, were higher than those in the limestone shrubland. The total potassium, total phosphorus, and available phosphorus contents of soil in the limestone shrubland were higher than those in the dolomite shrubland. Among the four types of land-use most strongly affected by human activities (paddy field, dryland, flue-cured tobacco field, and pear orchard), the nutrient contents (except potassium in the upper soil layer) were higher than those in the lower layer. The differences in nutrient contents between upper and lower layers were relatively small in the dryland and the pear orchard, whereas they were large for the paddy field and flue-cured tobacco field. The gray relational degree of various land-use types decreased in the following order: dolomite shrubland &gt; forest &gt; grass slope &gt; pear orchard &gt; limestone shrubland &gt; paddy field &gt; dryland &gt; flue-cured tobacco field. The dolomite shrubland had the best soil quality, while the flue-cured tobacco field had the worst. Of the four types of land use most strongly affected by human activities, pear orchard had the best soil quality. This study can provide reference for soil nutrient management and sustainable management in karst areas.

Studying soil erosion by evaluating changes in physico-chemical properties of soils under different land-use types

The effects of different land-use types on physicochemical properties and erodibility indices in suitable utilization of soil are the most important issue to be investigated. That’s why the current study was carried out to investigate changes in physical, chemical soil properties and erodibility indexes under different land-use types i.e., larch-fir forests, adjacent pasture, and riparian areas. Soil samples were collected from different land use in the Meydan Pond micro-basin. Five subsamples were taken at the 0–10 cm depth at five different sampling spots in each one of the three land-use systems (i.e., forest, pasture, and riparian areas). Results showed that silt content was around 38% higher in the forest soils over pasture and the riparian areas. Dispersion rate (80%) and erosion ratio (11%) were significantly higher in riparian areas over the pasture. In conclusion, pasture soils are resistant to erosion due to the higher amount of clay percentage (95%) and aggregation rate (38%) as compared to riparian areas that are more erodible. It is concluded that the river basin should be arranged according to the land capability classes’ principles to protect the soil's fertile layer from erosion to achieve the maximum productivity of crops.

Investigation of the Effects of Land Use on Chemical Water Quality Parameters; A Case Study of Başkonuş-Meydan Dam Lake in Kahramanmaraş

Water quality is in constant interaction with and changed according to time and place through natural and anthropogenic factors. It is also known that land use has a significant impact on water quality parameters. In this study, it was aimed to determine the effects of different land-use types (Forest, range and riparian) on water quality and which land-use type supports the most suitable drinking water for watersheds in the Baskonus Plateau in Kahramanmaras Province. The field studies were carried out in May 2019, and 2 sampling points were selected from each of the land-use types. Chemical properties (pH, EC) and some element concentrations (19 elements such as Al, As, Cu, B, Zn, Fe, P, Cd, Ca, Co, Cr, Pb, Mg, Mn, Mo, Ni, K, Na, and S) were investigated by using an ICP-OES. According to the results, the water obtained from forest areas is more suitable for drinking, having drinking water quality standards with a high pH value (7.59), and the Sulfur concentration of water obtained from range area (26.72 μg S /L) exceeded and did not comply with drinking water quality standards. When the chemical characteristics of the Meydan Dam were examined according to the regulated water quality standards declared in water pollution laws, it is clear that the dam basin has a high water quality standard (Class I). Therefore, a larger dam that can be built in this basin would be able to supply quality water that the Kahramanmaras metropolitan municipality needs. Consequently, before deciding on the construction of the dam for drinking water, land-use maps would be created in the basins, and the selection of basins that have dense and qualified forestland would provide quality water.

Land use effects on soil phosphorus behavior characteristics in the eutrophic aquatic-terrestrial ecotone of Dianchi Lake, China

Growing evidence suggests that land use has widespread effects on soil phosphorus (P) cycling, which can contribute to plant growth and environmental impacts. P pool and P behavior characteristics have identified as potential indicators of soil nutrient cycling and functions. In this study, we investigated effects of different land-use types (farmland and ecological buffer zone) on soil P fractions (i.e., labile P, moderately labile P, organic P, apatite P, and residual P) and soil P sorption-release characteristics at three sampling sites in the eutrophic aquatic-terrestrial ecotone of Dianchi Lake, China. In addition, we also identified key soil physicochemical properties that were significantly related to soil P fractions and sorption-release characteristics. Different land use induced changes in soil P fractions and P stocks. Organic P pool showed a significant difference between FL and BZ in all sites and other P pools displayed the site-specific responses. Soils in buffer zone have higher P buffer capacity (higher maximum sorption capacity and lower degree of P saturation) in comparison with farmland. Moreover, soil buffer capacity was significantly correlated with soil labile P. These results suggest buffer zone in lakeside may act as sink of P in reducing soil P loss. However, higher labile P and very low C: Po ratios (<100) in all soil samples indicate there is large amount of available P accumulated in soils and soil P loss risk in the aquatic-terrestrial ecotone is still high. Redundancy analysis results showed that the soil key physicochemical properties (soil organic carbon, total nitrogen, exchangeable Fe and Al concentration, and pH) were closely related to soil P fractions and sorption-release characteristics. Therefore, we conclude that soil P fractions (especially labile P, organic P) and key soil physicochemical indices are useful indicators for assessing the behavior of P in soils induced by different land use in the eutrophic aquatic-terrestrial ecotone of lakes.

Effects of land-use types on soil quality indices in ughoton community in Ovia north-east local government area, Edo state, Nigeria

The present study was conducted to examine the effects of different land-use types on soil quality indices. Surface soils were collected at 0-15 cm and 15-30 cm depth respectively from three land-use types: Cassava field, Oil palm, and Banana plantation. Samples were subjected to physical, chemical, and microbiological analyses using standard methods, and the result were subjected to descriptive statics. The extent of change in soil quality was assessed using soil quality indices as an index for soil fertility management. The result showed that oil palm plantation was highest in soil quality evaluated as compared to Banana and Cassava field. The fertility differences observed across the land use types were due to inherent soil properties such that farming practices that ensure accumulation of organic matter need to be encouraged in order to improve soil productivity. It is recommended that soil fertility management should be site-specific to enhance optimum yield and productivity.

Insight into the vertical characteristics of dissolved organic matter in 5-m soil profiles under different land-use types on the Loess Plateau.

Dissolved organic matter (DOM) is a natural chemical component of all soils and influences soil organic pollutant migration, nutrient cycling, and global climate change. Previous field studies have focused on a single ecosystem, such as cropland, grassland, or forestland. However, the potential effect of different land-use types on the vertical distribution of soil DOM quantity and quality remains unclear. This study investigated the vertical characteristics of DOM in 5-m soil profiles under different land-use types (cropland, grassland, and forestland) on the Loess Plateau. The data from ultraviolet-visible spectral and parallel factor analysis of fluorescence excitation-emission matrix spectrophotometry were combined. These results indicated that the mean content of dissolved organic carbon (DOC) in the 30-yr forestland (203.33 mg kg-1 soil) was the highest, and the lowest was observed in the cropland (83.70 mg kg-1 soil). Meanwhile, the mean DOC content of the forestland increased through time, particularly after 20 years. In other words, afforestation activities only significantly affected soil DOM after a long time (over 20 years). The DOC content of the cropland initially increased and then decreased with soil depth in the 1-m soil profiles, which may be related to agricultural activities. Three fluorescence components, including two humic acid-like substances (C1 and C3) and a tryptophan-like substance (C2), were identified from all samples. The humic acid-like components significantly decreased by 51% with soil depth, while the tryptophan-like component increased by 49%, particularly in the cropland. The variation in ultraviolet-visible spectral and optical indexes also indicated that soil DOM was dominated by both microbial and terrestrial sources. These findings help to understand the dynamics of DOC in deep soil profiles and the biogeochemical effects of DOM in the natural environment.

The effect of different ecosystems on groundwater consumption in an agro-pastoral ecotone of northern China from an innovative perspective

Water has always been the core resource for ecological security and social development of human life, especially in arid regions. The effects of different land-use types on the local groundwater resources were studied in Guyuan county, Hebei province, China. The results showed that the higher biomass was measured in cabbage, corn silage, potatoes, and oat plots, and the least biomass was measured in the natural grassland. The greatest fresh:dry ratio of biomass and water contents in cabbage was 24.2 and 155.4 t/hm2, respectively. Potatoes, corn silage, and oats had higher water contents, which were 72.4, 66.3, and 37.0 t/hm2, respectively. Driven by economic interests, vegetables and potatoes that were grown in the local area used a large amount of water and were mainly sold to the other parts of the country or even abroad. The high water usage is a threat to groundwater resources and the local ecological security. In the future, both the economic benefits and emergy should be analyzed to determine the real value and to objectively evaluate the input and the output of the ecosystem to save scarce ecological resources and to protect the local ecological security. Rain-fed artificial grassland including Chinese leymus and corn silage has a high development potential from the perspective of water consumption and productivity.

Factorial Kriging analysis and sources of heavy metals in soils of different land-use types in the Yangtze River Delta of Eastern China.

The objectives of this study are to analyse the pollution status and spatial correlation of soil heavy metals and identify natural and anthropogenic sources of these heavy metals at different spatial scales. Two hundred and twenty-four soil samples (0-20cm) were collected and analysed for eight heavy metals (Cd, Hg, As, Cu, Pb, Cr, Zn and Ni) in soils of different land-use types in the Yangtze River Delta of Eastern China. The multivariate methods and factorial Kriging analysis were used to achieve the research objectives. The results indicated that the human and natural effects of different land-use types on the contents of soil heavy metals were different. The Cd, Hg, Cu, Pb and Zn in soils of industrial area were affected by human activities, and the pollution level of these heavy metals in this area was moderate. The Pb in soils of traffic area was affected by human activities, and eight heavy metals in soils of residential area and farmland area were affected by natural factor. The ecological risk status of eight heavy metals in soils of the whole study area was light. The heavy metals in soils showed three spatial scales (nugget effect, short range and long range). At the nugget effect and short range scales, the Cd, Hg, Cu, Pb and Zn in soils were affected by human and natural factors. At three spatial scales, the As, Cr and Ni in soils were affected by soil parent materials.

Effects of Different Land-Use Types on Soil Erosion Under Natural Rainfall in the Loess Plateau, China

The Loess Plateau, which is located in the arid and semi-arid areas of China, experiences significant soil erosion due to intense human activities and soil erodibility. It is necessary to explore and identify the land-use types or land-use patterns that can control soil erosion and achieve certain agricultural production capabilities. This study established runoff plots with two slope gradients (5° and 15°) in north of Yan'an, one area of the Loess Plateau, with 3 single land-use types (cultivated land, CL; switchgrass, SG; and abandoned land, AL) and 2 composite land-use types (CL-SG and CL-AL). From 2006 to 2012, we continuously monitored the rainfall characteristics, runoff depth, soil loss, vegetation coverage, and soil physical properties. The results indicated a general trend in the number of runoff and soil loss events for the 5 land-use types: CL = CL-SG > CL-AL > SG> AL. The general trend for runoff depth, soil loss, their magnitudes of variation, and the slopes of rainfall-runoff regression equation was CL > CL-SG > CL-AL > SG > AL, whereas the rainfall threshold for runoff generation exhibited the opposite trend. Results of nonparametric test regarding runoff depth/EI30 and soil loss/EI30, where EI30 is the product of rainfall kinetic energy and the maximum rainfall intensity over 30 min, and the runoff depth-soil loss relationship regression indicated that the effect of CL-AL was similar to that of SG; SG was similar to AL; and CL-AL, SG, and AL were superior to CL with regard to soil and water conservation. Runoff depth and soil loss significantly increased as the slope gradient increased. Runoff depth and soil loss were significantly correlated with the soil particle size composition and bulk density, respectively. The strongest significant correlations were found between runoff depth and vegetation coverage as well as between soil loss and vegetation coverage, which showed that vegetation coverage was the primary factor controlling soil erosion. Therefore, the composite land-use type CL-AL and the artificial grassland (SG) are appropriate options because both soil conservation and a certain degree of agricultural production are necessary in the study area.

Differences in Biogeochemical Properties and Microbial Activities in Stream Segments with Changes in Land-use Type

Changes in land-use type can affect soil and water properties in stream ecosystems. This study examined the effects of different land-use types on biogeochemical properties and microbial activities of a stream. We collected water and sediment samples in a stream at three different sites surrounded by varying land-use types; a forest, a radish field and a rice paddy. Nitrogen contents, such as nitrate, nitrite and total nitrogen in the stream water body, showed significant differences among the sampling sites. The highest nitrogen values were recorded at the site surrounded by cropland, as fertilizer runoff impacted the stream. Soil organic matter content in the sediment showed significant differences among sites, with the highest content exhibited at the forest mouth site. These differences might be due to the organic matter in surrounding terrestrial ecosystems. Microbial activities determined by extracellular enzyme activities showed similar values throughout all sites in the water body; however, the activities in the sediments exhibited the highest values near the forest site and mirrored the soil organic matter content values. From these results, we conclude that different land-use types are important factors affecting water and sediment properties in stream ecosystems.

Physical properties and organic matter of Fluvisols under forest, grassland, and 100 years of conventional tillage

Although a large number of papers deal with effects of land-use change on soil properties, less attention is directed to the long-term effects of different land-use types on soil physical properties and organic matter in the lowland ecosystems.The objective of this study is to assess the long-term cumulative effects of change in land-use type on some soil properties in the continental lowland ecosystems of Western Serbia. Three adjacent land-use types (deciduous forest, natural grassland and arable soils that have been converted from forests for more than 100years) were chosen for the study. Disturbed and undisturbed soil samples were collected from nine sites at each of the three different land-use types from the depths of 0–10, 10–20 and 20–30cm in noncarbonated Fluvisol. Conversion of forest to grassland and arable soil has led to significant decrease in total porosity (TP), infiltration rate (IR) and soil organic matter (SOM). The bulk density (BD) was lower in forest compared to the adjacent grassland and arable (ex-forest) soils. In addition, microaggregate stability, determined by the clay dispersion ratio (CDR) and aggregated silt and clay (ASC) indices, was significantly higher in forest than in grassland and arable soil. In conclusion, the results of this study indicate that removal of permanent vegetation in the conversion process from forest and grassland areas to cultivated land may lead to loss of soil productivity and serious soil degradation. Obviously, there is a need for greater attention to developing sustainable land use practices in management of these ecosystems to prevent further degradation of soils in the region.

The effect of changes in land use on waterfowl species turnover in Finnish boreal lakes

Effects of different land-use types on nutrient and chemical run-off have been widely researched, but the total effect of changes in land use on communities of aquatic species is poorly known. We evaluated the effect of land-use change on waterfowl communities of boreal lakes. We conducted the study with topographicmaps and GIS-techniques in central Finland. We compared changes in the structure of waterfowl communities with changes in land use around 15 lakes over a period of 50 years. Over the period, agricultural land and bogs were reduced in area, while ditched areas increased significantly. The numbers of waterfowl breeding pairs and species increased slightly on the majority of lakes. The largest increases in breeding pairs were for Goldeneye Bucephala clangula and Teal Anas crecca. Interestingly, Mallard Anas platyrhynchos decreased in terms of both breeding pairs and the number of occupied lakes, although it has increased nationally. We found evidence of decreasing pair numbers of Mallards on lakes where adjacent dwellings increased in number. Changes in land use correlated with those in waterfowl communities but lake size appears to affect these results.After controlling for the effect of lake size, only the number of adjacent dwellings correlated significantly with changes in the number of breeding pairs ofMallards. According to our results, changes in the area of agricultural, bog or ditched land around lakes could not be clearly linked with changes in waterfowl communities.

Land use effects on the properties of an Alfisol on the Jos Plateau, Nigeria

This study was carried out to determine the effects of different land-use types on the properties of an Alfisol on the Jos Plateau, Nigeria. Areas being used for nature conservation (forest), grazing and maize cultivation were chosen, and the three are contiguous within a nearly level, moderately well-drained site. Within each of the three land-use areas, a plot of 30 x 20 m was chosen. Each plot was divided into 6 grids of 100 m2 size. Within each of these grids, four sampling sites were chosen by throwing up a coin four times. The four surface soil (0–5 cm depth) samples taken at the points where the coin landed, were mixed to form the composite sample, out of which sizeable portion was taken. This means that six soil samples were taken for each land use area (forest, grass, and cultivated). Same procedure was repeated for each of the following soil depths 5–15, 15–30 and 30–50 cm. Laboratory soil analyses were carried out while analysis of variance was used to test the significance of mean difference. The results show that forest clearing for grazing and maize cultivation has lead to significant decreases in most soil fertility variables. Organic matter levels of the grassland and cultivated soils are just about 28% and 13%, respectively, of that of the forest soil in the 0–5 cm depth, while they are 36% and 19%, respectively, in the 5–15 cm depth. Exchangeable cations and effective cation exchange capacity are also significantly higher in the forest soils. The effects are attributable to soil organic matter decomposition and nutrient removal resulting from forest clearance, maize cultivation and grazing. Hence, for sustained agricultural productivity, the soils require adequate inorganic and organic fertilizer additions together with appropriate cultural practices such as agroforestry, crop rotation and mixed cropping involving legumes.

Effects of different land-use types on soil quality in the hilly area of Rawalakot Azad Jammu and Kashmir

Vegetative cover plays an important role for the quality of soil especially in hilly and mountainous areas such as Azad Jammu and Kashmir where erosion is a major threat to the ecosystem and productivity. The study focuses on the impact of land-use types on soil quality by measuring the differences in chemical and physical properties at three sites in adjacently located natural forest land (forest), fallow grassland (grass) and arable land (arable). Soil samples from 0-15 and 15-30 cm depth were collected and examined for particle distribution, dry bulk density, organic matter (OM), pH, macro- and micro-nutrients. Land-use types had a significant effect on primary soil particle distribution. Highest clay content was found in forest and highest sand content in arable. Forest had relatively the highest levels of OM, macro- and micro-nutrients and arable the lowest. Most of the properties of the 0-15 cm surface level of grass were similar to those observed in the 15-30 cm level in forest. Arable exhibited lowest nutrient status and poorest physical conditions, indicating a degrading effect of arable cultivation practices on soil. Grass and arable showed, compared to forest, a 30–60% average increase in bulk density and 26–66% average decrease in OM. Regression analysis showed a significant correlation of OM with available phosphorus and potassium while it had negative correlation with dry bulk density and pH. Natural vegetation appeared to be a main contributor of soil quality as it maintained the organic carbon stock, and increased the nutrient status of soil and is therefore important for sustainable development of Azad Jammu and Kashmir and other similar areas. Furthermore, OM was shown to be an important indicator of soil quality.