Grass Areas Research Articles

Carbon, nitrogen and biomass activity under different managements system in Rio Verde – Goias State (Brazil)

The aim of this study was verify alterations in soil biologic attributes under different management systems at Cerrado. Soil samples were taken at dry (july 2006) and wet (february 2007) season at Red distrofic Oxisol (50 – 70 % clay) in Rio Verde, Brazil (17 o 39’07’’S - 51 o 06’49’’O) under: native Cerrado (CE), 20 years old pasture (PA), 29 years old conventional tillage (CT), and 10 and 15 years old no-tillage (NT - 10 and NT - 15). Were analysed: soil and microbial carbon and nitrogen levels (C, N, Cmic and Nmic), Cmic:C and Nmic:N ratios, basal respiration (BR) and metabolic quotient (qCO 2 ). Higher soil moisture at wet season led 100 % higher Cmic and Nmic and lower qCO 2 level than dry season. Among the management systems, the grass cultivation , animal wastes and area reform were possibly majors factors with which led to higher Cmic e Nmic values in PA, indeed under degradation, than any other one. NT adoption was important to increase Cmic and Nmic, and at least after 10 years pointed out higher values than CT.C and N microbial were more sensitive than total C and N, while other biological parameters also did not show differences.

Are golf courses a source or sink of atmospheric carbon dioxide? A modelling approach

Sports facilities have been shown to have a positive impact on local biodiversity, quality of life, and the economy. Their impact on global carbon balances is less clearly understood. Increased concentrations of atmospheric carbon dioxide (CO2) have been linked with global climate change. Currently there is a debate as to whether amenity turf is a net source or a net sink for atmospheric CO2. The turf grass of a natural sports pitch will sequester carbon through photosynthesis, but there are numerous emission sources associated with the management of turf which release CO2 into the atmosphere. These include the engines used to power mechanized operations such as mowing and spraying, the application of agrochemicals, including fertilizers, and the disposal of waste. In order to determine whether a real-world example of a sports facility was a source or sink of carbon a mechanistic mass balance model was developed. Analysis indicated that the areas of the golf course that received the most management attention were a net source of carbon emissions. The magnitude of these releases was significantly different on an equal-area basis ( p < 0.01). The net carbon budget for turf grass areas across the whole golf course accounting for the sequestration by the turfgrass was −33.01 MgC/year. The mature trees that formed an integral part of the landscape of the modelled course had a significant impact on the net carbon balance, resulting in overall net sequestration of −177.3 MgC/year for the whole golf course, equivalent to −1.93 MgC/ha/year. The variability in the size, shape, and vegetation composition of different golf courses has a considerable impact on their net carbon balance, and the resultant environmental impact of sports facilities must be assessed on an individual basis.

The influence of grass biomass production on hippopotamus population density distribution along the Luangwa River in Zambia

Hippopotamus is a selective nocturnal grazer consuming 50 kg of grass. Due to its large body size, it requires large areas of grass often exceeding 5 hectares within 2-5 km of the water body to maintain good body condition. In this study, hippo population size and density, grass biomass and grazing capacity were assessed in March 2008 along a 165 km stretch of the Luangwa River. The study area was subdivided into study blocks, A, B, C, D, E and F. Methods used were: river bank total counts, quadrat sampling and identification of all grass species, clipping of grass in a quadrat, drying of clipped grass at constant temperature of 70oC and weighing to obtain dry weight. Grazing capacity of the hippo was estimated based on grass biomass values obtained during the study. Hippo population density was then matched with grass biomass distribution along the study blocks A-H. Total primary production was 62, 800 kg with mean biomass per study block of 7, 850 kg /ha-1 (in 2008). Grazing capacity was 1 hippo/6 ha-1. Grass biomass varied significantly between river segments being higher in study blocks A, B and E and lower in study blocks C, D, F and G. Mean hippo density was 33 individuals/km stretch of the river. Hippo density was found to be above 33/km in study blocks A, B and E which had higher biomass and lower than 33/km in study blocks C, D, F and G. Hippo population density distribution was found to be influenced by grass species diversity and amount of biomass produced which also determined grazing capacity. In light of global climate change and changing rainfall patterns, more studies are required to determine the influence of rainfall on primary production and how this would affect the increase or decrease in hippo density and grazing capacity in the long-term. Key words: Hippo, density, grazing capacity, grass biomass.

Patch vegetation and water redistribution above and below ground in south‐east Spain

AbstractTwo sites, one dominated by Anthyllis cytisoides and the other by Retama sphaerocarpa in south‐east Spain were instrumented to measure soil matric potential to a soil depth of 1 m and soil water content to 2·75 m depth within shrubs and grass areas. Soil cores and underground surveys were taken to estimate root length and soil texture, ground cover volume was measured and runoff traps were installed to estimate overland flow in grass and shrub areas. The outcome of the results was summarised as a conceptual model to describe the flow of water within patch vegetation, where the main dominating factor of patch vegetation was found to be the function of shrub canopy/root systems. The results illustrated that not only the dynamics of runoff/runon between grass and shrub areas were significant in redistributing rainfall, but also the morphology of shrub species caused significant differences to the accumulation and movement of water in shrub zones. A comparison of growth and flowering times of grass and shrub species showed that soil water availability for each species differs throughout the year. Such an understanding of water movement within patch vegetation of different species shows that sustainable management practices of semi‐arid areas must take into account not only natural vegetation patterns, but also the function of each plant type. Copyright © 2011 John Wiley & Sons, Ltd.

Nitrogen Mineralization in Riparian Soils along a River Continuum within a Multi‐Land‐Use Basin

Nitrogen dynamics in riparian systems are often addressed within one land‐use type and are rarely studied on watershed scales across multiple land uses. This study tested for temporal trends and watershed‐wide spatial patterns in N mineralization and identified site factors related to N mineralization. We measured net N mineralization in situ at monthly intervals for 1 yr at 32 riparian sites along the 124‐km length of the Calapooia River, Oregon. We observed seasonal trends of mean net N mineralization with relatively low rates in the fall (29.8 kg N ha−1 yr−1) and winter (30.1 kg N ha−1 yr−1) and relatively high rates in the spring (122.1 kg N ha−1 yr−1) and summer (99.7 kg N ha−1 yr−1) when conditions for microbial activity and decomposition were likely enhanced. Annual net N mineralization on an area basis ranged from −13.5 to 234.0 kg N ha−1 yr−1 with a mean for all sites of 50.1 kg N ha−1 yr−1 Annual net N mineralization per kilogram of soil ranged from −16.2 to 207.1 mg N kg soil−1 yr−1, with a mean for all sites of 64.4 mg N kg soil−1 yr−1 Regression analysis revealed hardwood basal area and coverage of grass as significant positive predictors of kilograms of N mineralized per hectare. Location along the river explained 22% of the variability of N mineralization per hectare, indicating that riparian areas may function differently along the length of the river.

Gas composition of the surface air in Moscow during the extreme summer of 2010

In summer 2010, anomalously hot weather occurred in the European part of Russia. It was caused by a blocking anticyclone of an unusually high intensity. West winds were stopped in the whole column of the troposphere, from the Earth's surface up to the lower stratosphere, for two months. During this entire period, the concentration of gaseous and aerosol pol� lutants grew in the nearsurface air. In the end of July and the first half of August, this extreme situation become even more complicated due to the arrival of air masses from the areas of forest, peat, and grass fires to Moscow. By the measurements data from the station of the Institute of Physics of the Atmosphere, Russian Academy of Sciences (IPA RAS), the concentrations of reactive gases NO, NO 2 , CO, and O 3 exceeded both the average daily and the general maximum permissi� ble concentration (MPC). The concentrations of greenhouse gases CO2, CH4, and other hydrocarbons were also excessive. Analysis of variation in gas content in the nearsurface air and in the atmospheric bound� ary layer has shown a close dependence on vertical stratification of the atmosphere. The blocking anticyclone above the European part of Russia recorded in summer 2010 significantly exceeded all the previously recorded ones in its dura� tion. According to (1), the duration of summer block� ing anticyclones in the Northern and Southern Hemi� spheres has not exceeded three weeks for the last forty years, while the longest periods of anticyclonic weather in winter have not lasted more than a month. Anomalies in the frequency and intensity of atmo� spheric blockings were recorded most often in the years of El Nino/La Nina phenomenon, including 2010 (see, for instance, (2)). The formed hot weather lead to the outbreak of numerous forest and peat wildfires. In total, 29 000 wild� fires were recorded in summer 2010 with a total burned area of 1.2 million ha (3). And though the wildfire intensity in 2010 was weaker than in some other years (e.g., 40 000 wildfires with a total burned area of about 1.5 million ha were recorded in 1972; 28 000 wildfires of 4.2 million ha, in 1998; 29 000 wildfires of 2.4 mil� lion ha, in 2009), the economic, ecological, and social consequences were more significant. The most important consequence of the emer� gency situation that appeared in summer 2010 was change in the chemical composition of the atmo� sphere above the European territory of Russia and West Siberia. Cities and settlements were covered with a dense haze when they happened to be in smoke trails of forest and peat wildfires. The presence of obviously extreme quantities of aerosols in the nearsurface air caused extreme concern and a demand for introduc� tion of required protective activities (3). No less nega� tive an effect on people's health and ecosystems was made by a significant change in gas composition of the atmosphere.

Foraging habitat selection by breeding Common Kestrels Falco tinnunculus on lowland farmland in England

Capsule Breeding Common Kestrels prefer to forage over recently cut grass than all other habitat types on farmland. Aims To identify foraging habitat and prey of Common Kestrels during the breeding season. Methods We observed seven pairs of Common Kestrels during the breeding season over three years, using fixed vantage point observations. We recorded foraging attempts, and habitat and prey data for where the birds chose to forage. Compositional Analysis was used to establish use of each habitat category relative to that habitat’s availability within the Kestrels’ observed foraging ranges. Results We found that Kestrels select habitats non-randomly, with cut grass (le;5cm, all cut less than two weeks previously) being the most used relative to availability. Prey taken varied with grass height: the ratio of mammals to invertebrates was greater on cut grass (4.36 mammals: 1 invertebrate) than on longer, uncut grass swards (1.73 mammals: 1 invertebrate). Conclusion Our results highlight the importance of areas of long and short grass in close juxtaposition, to provide conditions suitable for prey and access to them, respectively. The creation and maintenance of such small-scale habitat heterogeneity will be the key to maximizing the benefits of English agri-environment schemes for Common Kestrels.

A análise do uso da terra no entorno do trecho oeste do Rodoanel Mario Covas na cidade de São Paulo por meio de técnicas de Sensoriamento Remoto

The construction of a highway may interfere with urban dynamics when transform the land use around it. The western section of the road axles Mario Covas in the Metropolitan area of Sao Paulo in the neighborhoods of Perus and Jaragua in Sao Paulo city was studied with the characterization of the use and occupation of land around it. We did a survey of information with field work and were used remote sensing techniques for mapping. In a GIS have been made both types of digital classification, an analog and a automatic, a high resolution (IKONOS of 2002) and aerial photographs of 1994. For the comparative analysis showed that the classification analog was the most suitable for temporal analysis, because it allowed the preparation of thematic maps and better visualization of the results. With the quantitative analysis of the generate classes and worked, it was concluded, it was concluded that, in the year 1994 to 2002, the dense green area increased, the area of grass and scattered trees fell, the area of bare ground decreased, the built area increased. The results were organized in thematic maps showed the temporal analysis.

CASBEE－HI作成過程における緑の環境改善効果をめぐる論点

CASBEE for Heat Island Relaxation ,revised and updated in July 2010, reappraises greenery, more specifically, trees as being effective in mitigating a thermal environment. In concrete terms, tall and medium height trees and ground cover plants were assessed independently as cover over the ground, and it was established that the amount of evapotranspiration in the area of a tree crown was 3 times that of the same area of turf grass. In this paper we, as a committee, have used objective data to verify the process in the argument and established fresh criteria for evaluating medium and tall tree. Finally we have discussed our perceptions of what we think is currently lacking in the field of greening from the view of the continuing to improvement to performance evaluation.

Effect of intercropping, phosphorus fertilization and rhizobium inoculation on the growth and nodulation of some leguminous and cereal forages

A field experiment was carried out for two consecutive seasons (2005/2006 and 2006/2007) in the Demonstration Farm of the Faculty of Agriculture at Shambat, University of Khartoum, Sudan, to study the effect of intercropping, phosphorus application and Rhizobium inoculation on the performance of some leguminous and cereal forage crops. The treatments used were pure stand, a mixture of Clitoria, lablab and Sudan grass, phosphorus fertilizer and Rhizobium inoculation. They were laid out in a completely randomized block design with three replications. Growth attributes, number of nodules, weight of nodules and prussic acid (HCN) were measured. Results showed that stem thickness was significantly affected by intercropping and addition of phosphorus. Sole crops produced forage with thicker stems during the growth of the first crop, while intercropped plants treated with phosphorus developed thicker stems during the second cut (ratoon). The plant cover was significantly higher for Clitoria than the other species. Intercropping and addition of phosphorus increased plant height of Sudan grass. The leaf area of Clitoria was increased with the addition of phosphorus and intercropping in the first crop, but sole Clitoria scored higher leaf area during the second cut. Lablab leaf area was significantly increased with addition of phosphorus and intercropping in the two seasons. Intercropping of Sudan grass with lablab and Clitoria resulted in large leaf area of Sudan grass. Leaf to stem ratio of Clitoria was mainly increased with the addition of phosphorus. Intercropping lablab with Clitoria significantly increased lablab leaf to stem ratio. The two-combination intercropping of Sudan grass increased its leaf to stem ratio. Rhizobium inoculation, legume to legume intercropping and addition of phosphorus enhanced nodulation and increased the number and weight of nodules. Phosphorus significantly reduced the amount of HCN in the forage of Sudan grass.

Biosolids Effects in Chihuahuan Desert Rangelands: A Ten-Year Study

Arid and semiarid rangelands are suitable for responsible biosolids application. Topical application is critical to avoid soil and vegetation disturbance. Surface-applied biosolids have long-lasting effects in these ecosystems. We conducted a 10-year research program investigating effects of biosolids applied at rates from 0 to 90 dry Mg ha−1on soil water infiltration; runoff and leachate water quality; soil erosion; forage production and quality; seedling establishment; plant physiological responses; nitrogen dynamics; biosolids decomposition; and grazing animal behavior and management. Biosolids increased soil water infiltration and reduced erosion. Effects on soil water quality were observed only at the highest application rates. Biosolids increased soil nitrate-nitrogen. Biosolids increased forage production and improved forage quality. Biosolids increased leaf area of grasses; photosynthetic rates were not necessarily increased by biosolids. Biosolids effects on plant establishment are expected only under moderately favorable conditions. Over an 82-mo exposure period, total organic carbon, nitrogen, and total and available phosphorus decreased and inorganic matter increased. Grazing animals spent more time grazing, ruminating, and resting in biosolids-treated areas; positive effects on average daily gain were observed during periods of higher rainfall. Our results suggest that annual biosolids application rates of up to 18 Mg ha−1are appropriate for desert rangelands.

INFLUENCE OF MOWING DOWN FLOATING-LEAVED PLANTS ON WATER BODY STRUCTURE IN LAKE SUWA

Numerous attempts have been conducted in order to recover emergent plants and submerged plants in various lakes. However, floating-leaved plants, which make water quality worse, have been rarely focused. The purpose of this paper is to evaluate the effect of mowing down the floating-leaved plants area partially in Lake Suwa, where floating-leaved plants-dominated state is observed in shallow zone. We measure water temperature, turbidity and water velocity inside and outside of the floating-leaved plants area. It is confirmed that 1) The variation range of water temperature inside of floating-leaved plants area is smaller than that of outside. 2) Floating-leaved plants lessen the vertical water circulation. 3) Outside of floating-leaved plants area is easier to be influenced by cold water than inside when cold water intrude into water grass area. 4) Turbidity inside of floating-leaved plants area is higher than outside. 5) The leaves of floating-leaved plants become the resistance of surface current.

Survival and growth of exotic grasses under plantations of ACACIA mollissima in north-west Himalaya

The experiment was conducted in the existing plantations of A. mollissima having three density classes (D1, D2 and D3) at Dr. Y. S. Parmar University of Horticulture and Forestry Solan (India). Adjacent grassland was considered as control. Three exotic grasses viz., Setaria sphacelata var. Narok (S1), Setaria sphacelata var. Kajungula (S2) and Panicum maximum (S3) were planted under each density class and the grassland in the month of July. Survival and growth parameters (density and basal area) of these grasses were recorded after first growing season. Survival (%), density and basal area of exotic grasses decreased significantly under trees. Survival (%) varied from 73.33 to 82.22 in grassland and 50.00 to 7.8% under plantations. Density (tillers/m2) of exotic grasses varied from 28.42 to 39.47 in grassland and 11.92 to 27.22 under plantations. Basal area (cm2/m2) of the grasses ranged from 9.56 to 43.05 in grassland and 0.58 to 15.19 under plantations. D3 density of trees showed more adverse effects on grasses followed by D2 and D1. Among the three grasses Panicum maximum showed more tolerance to the effect of trees. However, the other two grasses showed moderate success under trees.

Bullous Leg Lesions Caused by Culicoides Midges after Travel in the Amazon Basin

A 36-year-old man presented with 1 day of blistering lesions on the lower extremities. Two days before presentation, he had traveled to several rural communities in the Peruvian Amazon. During that trip, he had hiked through several areas of damp soil, decaying plants, and dense grass reaching up to 50 cm in height. He awoke the next morning with numerous confluent, erythematous, pruritic, non-blanching papules that were circumferential around both ankles. Over the next day, multiple bullae up to 4.5 cm in diameter developed with surrounding edema (Figure 1). The patient was treated with prednisone (50 mg daily) by mouth for 3 days, followed by routine wound care with topical antimicrobials, dressings, and topical hydrocortisone for pruritus. The lesions stabilized in size by the third day and had largely resolved by 14 days with minimal scarring. Figure 1. View of the patient's right ankle 1 day after travel, with prominent bullae and numerous confluent papules. Soft-tissue edema is obscuring the medial malleolus. This figure appears in color at www.ajtmh.org. This case was caused by midge bites, likely from the hematophagous species Culicoides paraensis and insinuatus (Figure 2). These small insects are widespread in the Peruvian Amazon, where they favor wet areas, grass, and decaying vegetation such as the remains of banana (platano) trees.1 Approximately 1 mm in size and noiseless, they are difficult to see and may be overlooked in vector-avoidance strategies despite being vectors for Oropouche virus and other pathogens. Bites to humans may manifest as an immediate-type hypersensitivity reaction with urticaria or as presumably delayed-type reactions with papular, ulcerating, or bullous lesions that can require weeks to resolve.2 Travelers to rural regions in the tropics should adhere carefully to vector precautions, including the use of N,N-diethyl-meta-toluamide (DEET), permethrin, and physical barriers such as heavy boots and tucked-in trousers to prevent bites and their potential consequences. Figure 2. Dissecting microscope images (40×) of a female C. paraensis collected near Iquitos, Peru in the vicinity of where the subject traveled. (A) Thorax and legs. (B) Head. (C) Abdomen. (D) Wing. This figure appears in color at www.ajtmh.org.

Detection of ancient reindeer pens, cultural remains and anthropogenic influenced vegetation in Byrkije (Børgefjell) mountains, Fennoscandia

Significant parts of Fennoscandia have been used by Saami reindeer husbandry for many centuries, and this has altered the vegetation cover. Cultural remains like abandoned reindeer pens (giedtieh) and milking pens (buhtjeme-aevieh) are found in connection to abandoned seasonal dwellings (låavth-gåetieh and derhvie-gåetieh) for the reindeer Saami groups. The abandoned pens still appear as oval shaped areas of luxuriant grass- and herb-rich vegetation surrounded by meager mountain vegetation, due to slow growth of vegetation. This paper presents a study on using visual analysis of aerial and satellite imagery, multispectral classification (hyper-clustering) and linear spectral unmixing (SAM) of satellite imagery to detect Saami cultural remains. Visual analysis of high spatial resolution satellite imagery (QuickBird-2) and aerial photography enabled detection of maintained and abandoned reindeer pens, milking pens and old individual dwelling sites. Signs of them can also be detected by middle resolution imagery (Landsat TM/ETM+ and IRS-P6) but are to coarse to use since the spatial extent of these remains is to small to detect without prior knowledge of their location in the landscape. Using the classification methods on the fused Landsat ETM+ PAN imagery, we were able to detect the pens substantial to almost perfect (70–95% accuracy). The hyper-clustering method was slightly better than the SAM-method, but the first was more labor demanding. The results from this study show that use of satellite imagery is a helpful tool for the detection of even subtle traces in vegetation of cultural activities in large-scale mountain landscapes.

Spatial variability models of CO2 emissions from soils colonized by grass (Deschampsia antarctica) and moss (Sanionia uncinata) in Admiralty Bay, King George Island

AbstractSoil CO2 emission is an important part of the terrestrial carbon cycling and is influenced by several factors, such as type and distribution of vegetation. In this work we evaluated the spatial variability of soil CO2 emission in terrestrial ecosystems of maritime Antarctica, under two contrasting vegetation covers: 1) grass areas of Deschampsia antarctica Desv., and 2) moss carpets of Sanionia uncinata (Hedw.) Loeske. Highest mean emission was obtained for the Deschampsia (4.13 μmol m-2 s-1) developed on organic-rich soil with a strong penguin influence. The overall results indicate that soil temperature is not directly related to the spatial pattern of soil CO2 emission at the sites studied. Emission adjusted models were Gaussian and exponential with ranges varying from 1.3 to 2.8 m, depending on the studied site and vegetation cover.

Life history traits of the pseudometallophyte Thlaspi caerulescens in natural populations from Northern Europe

We examined recruitment, survival, life cycle and fecundity of two metallicolous (M, on metalliferous calamine soils) and two non-metallicolous (NM, on normal soils) populations of Thlaspi caerulescens in Belgium and Luxemburg. In each population, permanent plots were monitored over two reproductive seasons. In M populations, plots were located in two contrasting environments (grass versus grove) in order to test the influence of vegetation cover on life strategy. Our results show that the monocarpic life cycle is dominant in all populations of T. caerulescens. However the length of the pre-reproductive period varies from several months (winter annuals) to 1 year or more (perennials), and is partly related to plant origin (M versus NM). Most plants growing in metalliferous environments were annuals, whereas NM plants were mostly perennials. These differences in life cycle were related to differences in survival during summer, which was better in NM than in M populations. Within each M population, different survival conditions and life cycles were observed according to vegetation cover. Plants growing in grass areas were mostly annuals and had a low survival rate in summer whereas grove plants were mostly perennials and survived better in summer. Our results suggest the selection of stress avoiders (shortening of life cycle) in M populations of T. caerulescens but only for individuals growing in grass areas. Summer survival seems to play a key role in selection of life strategy in T. caerulescens.

Patch occupancy, number of individuals and population density of the Marbled White in a changing agricultural landscape

Metapopulation theory predicts the occurrence of animals in habitat patches. In this paper, we tested predictions based on this theory, including effects of spatial autocorrelation, to describe factors affecting the presence, local number of individuals and density of the Marbled White butterfly Melanargia galathea in habitat patches spread across the agricultural landscape of southern Poland. This agricultural landscape has undergone significant changes in recent decades due to the country’s political transformation and is currently characterized by a large proportion of fallow (abandoned) land. We compared 48 occupied habitat patches with 60 unoccupied ones. Positive spatial autocorrelation was found in the number and density of individuals in habitat patches. The probability of patch occupancy was higher for patches that were larger, had a higher proportion of edges, were located closer to the nearest neighbouring local population and to the nearest piece of fallow, contained a smaller area of cut grass, and also had more nectar resources. The number of Marbled Whites in habitat patches was positively related to the patch area, the distance to the nearest fallow and the abundance of nectar resources, but was negatively related to the density of shrubs. The density of individuals was positively related to abundance of flowers, proportion of edge in a patch and distance to the nearest fallow, but it was negatively related to patch area, vegetation height and grass cover. These results indicate that recent land-use changes in agricultural landscapes have had both positive and negative effects on the presence and local number of individuals and density of the Marbled White. These changes affect the metapopulation of the species through changes in habitat quality and landscape connectivity in the area surrounding habitat patches.

Differences in distribution patterns around river confluences among hydrophilic vegetation groups

AbstractIn riparian areas, the distribution patterns of plant species are generally considered to depend on their flooding tolerance. Areas around river confluences are known to experience frequent and/or strong flooding events and provide diverse habitats for plants in riparian areas. However, the degree to which hydrophilic vegetation types increase their distribution around confluences may depend on their flooding tolerance. To test this hypothesis, we compared patch numbers and total areas of ten vegetation groups between confluences and single‐flow areas. The vegetation groups were classified on the basis of life form and morphology of dominant species. Additionally, we compared total area of natural bare ground (an index of flooding disturbance) between confluences and single‐flow areas. We found that patch numbers of annual grass, forb, and vine, perennial grass and forb, and riparian forest vegetation, as well as total areas of annual forb and vine, perennial grass and forb, bamboo and riparian forest vegetation, and natural bare ground, were greater around river confluences than in single‐flow areas. On the other hand, patch numbers of shrub vegetation and total areas of annual grass, perennial vine, willow, and shrub vegetation decreased around confluences. These results suggest that confluences enhance diverse, but not all, types of habitat for hydrophilic vegetation. Thus, river confluences are a key element in maintaining diverse riparian vegetation.

A numerical modelling approach for biomass field drying

In grass conservation systems, the field drying process of cut grass is an important function since it determines subsequent losses and possible hazardous effects of during silage. The drying process of harvested grass was evaluated using two different numerical approaches. Firstly, an existing experimentally-verified analytical model was used. Several parameters were improved from previous studies such as the evaluation of stomata conductance from outside climate variables. Secondly, a CFD modelling approach was applied to open field drying process of the biomass. The cut biomass in the field was simulated using the equivalent macro-porous medium approach. Experimental values were used to obtain realistic and accurate boundary conditions. The developed CFD model was validated using the existing analytical model that is based on evaporations as estimated from the Penman equation. An acceptable agreement between simulated and measured values of water content was obtained. The mean difference in the estimated outputs from the two models was 8%. Condensation occurred during the night and was correctly simulated by both types of models. In general, a good correspondence was found between the two approaches. The use of the CFD model reveals the climate heterogeneity in the grass area and also, creates the possibility of applying the model as a decision support model for an enhanced treatment of the grass after cutting.