Agricultural Landscapes Research Articles

Ecological Capacity and Bioenergy Potential of Agrocenoses as a Way of Sustainable Agriculture

Background: Calculation of bioenergy potential and ecological capacity are promising methods for assessing the state of an agro-landscape, allowing us to promptly respond to changes in its sustainability. The article presents the results of soil research and calculation of bioenergy potential of the farm territory in the zone of dry steppe on chestnut soils. Methods: Assessment of anthropogenic load on agricultural landscape is based on ecological standards and point system of relative fertility. The determination of the ecological capacity by BEPT of an agrocenosis occupied by winter wheat and sunflower was carried out according to the method of V.M. Volodin, R.F. Eremina, N.F. Mikhailova. Determination of erosion and geomorphological characteristics of the research object was carried out using geoinformation technologies. The basis for creation of digital elevation model (DEM) is the data of radar survey of the Earth surface (SRTM4). Result: Soils of the research object have low and average humus content. Nitrogen level in the soil varies from very low to good; nitrogen availability in the fields is average. Provision with mobile phosphorus is average. Soil potassium content is mostly high. As a result of calculations, it was found that in the conditions of the dry steppe zone, the bioenergy potential of the agrolandscape area occupied by winter wheat is 2735.72 GJ/ha, sunflower-2647.4 GJ/ha. At the same time, the ecological capacity of the field occupied by winter wheat is 2764.6 GJ/ha and sunflower-2676.8 GJ/h.

Seeds and farmers' rights as drivers of change on food systems

In the heart of Kenya's vibrant agricultural landscape lies a fundamental aspect crucial for food security, cultural heritage, and economic resilience: the right to seed. Embedded within the fabric of traditional farming practices, the right to seed encompasses the freedom of farmers to save, exchange, and utilize traditional and farmer-bred seeds. In Kenya, as in many other countries, this right is not only a legal concept but a cornerstone of agricultural sovereignty. However, its preservation faces challenges in the face of globalization, corporate interests, and evolving intellectual property regimes. Yet, amidst these challenges, significant strides are being made, with collaborative efforts at the global level, particularly through initiatives led by the Convention on Biological Diversity (CBD) and the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA), aimed at promoting and protecting farmers' rights. Every smallholder farmer has the right to safe, nutritious and healthy food and the ability to sustain themselves and their societies with the existing endorsed resources. The concept of farmers’ rights came out as a subject of debate in international agricultural circles, spearheaded by the Food and Agriculture Organisation of the United Nations (FAO). This includes the right to save, use, exchange and sell farm-saved seed and propagating materials, the right to protect traditional knowledge among others. In developing countries, the right to seed is a fundamental aspect of agricultural sovereignty and food security. This still emulates the subject debate from FAO. However, attention in scientific literature and policy circles for both seeds and farmers’ rights are compromised. This paper employs mediation analysis to explore the causal relationship between seed rights, farmers' rights, and food sovereignty, highlighting the pivotal role of smallholder farmers in shaping sustainable food systems. The findings underscore the importance of inclusive policies that prioritize farmers' rights and empower local communities to sustainably manage their seed resources. Key words: Farmer-managed seeds, seed banks, Access, smallholder farmers and benefit-sharing

Trajectories and drivers signalling the end of agricultural abandonment in Trás-os-Montes, Portugal

Agricultural abandonment has given rise to novel landscape dynamics worldwide. This paper investigates abandonment and post-abandonment dynamics in continental Portugal as a hotspot of landscape change. We mapped the spatial patterns and drivers of recent (1995–2018) land use changes in a remote mountainous region as post-abandonment trajectories, based on detailed land use/land cover data made available by the Portuguese government. We showed that ‘Revegetation’ trajectories, indicative of agricultural abandonment, were still widespread between 1995 and 2007. However, between 2007 and 2018, the landscape was much more stable with ‘Return to agriculture’ as the dominant change trajectory. To understand what drives landscape changes after abandonment, we explored the influence of a wide range of potential biogeophysical and socio-economic drivers on the observed trajectories. We contrasted different landscape outcomes in binary logistic regression models with the potential underlying drivers as independent variables. The regressions revealed that the most significant determinants of these alternating dynamics are existing land use, climate, slope, protection regime and accessibility. The results of the regressions are at times counterintuitive and give important indications of the changing spatio-temporal scales at which these variables exert influence on the landscape outcomes. However, the regression models’ limited accuracies highlight the need for deeper investigation of the socio-economic and historic context of the observed changes. Improved understanding of the (drivers of) alternative dynamics following agricultural abandonment can help inform policy decisions regarding agriculture and cultural landscape preservation.

Segetal plants of agricultural landscapes of the Southern Non‐Chernozem zone as a source of biological resources

Aim. To identify economically significant species of segetal plants of agrophytocenoses in the Southern Non‐Chernozem zone and assess their dynamics with changes in anthropogenic load.The study was carried out by analysing geobotanical descriptions of agrophytocenoses in the Southern Non‐Chernozem Zone. The species diversity of economically important species was established during the period of extensive farming (1929–1933), the beginning of intensification (1936–1938), a high level of intensification (1981–1983), and a period of decreasing intensity of farming (2012–2022).At all stages of the study, groups of forage, medicinal and honey plants were round to have a high species diversity. The presence of individual representatives of vegetable, vitamin, insecticidal and ornamental species in agrophytocenoses was established.Changes in the nature and degree of anthropogenic pressure on agrophytocenoses has led to a significant transformation of species composition and abundance of representatives of economically significant groups. The smallest number of these was noted in the 1980s. Currently, species diversity has increased due to a decrease in the intensity of agriculture in the region.

Assessing the Impact of Geospatial Susceptibility on the Rural Agricultural Landscapes of Village Settlements in Southwestern Nigeria

A theoretical framework for agricultural landscape pattern transitions in rural areas is proposed to fill the gap of current research with an empirical study in the Alabata farm settlement in Ogun State, Southwest Nigeria. Adopting the use of ArcGIS 10.8 and Surfer 27.3 the surface area and volume of the ground surface degraded and exposed to harsh weather conditions due to both natural and man-made anthropogenic activities causing runoffs and continuous soil erosion were calculated, which have affected agricultural production and sent some of the farmers packing, abandoning their farmlands. The farm settlement within the total sampled frame area of 1.50 km2 covers a total distance of 5.11 km. The sample frame was divided into 36 frames with similar ecological microclimates, topographical features, terrain, and soil types that fell into either of the two identified soil types: 1 and 2. The study involved the completion of a questionnaire onsite using three major criteria and only 23 farmers responded positively to the few questions as farmers who were either living on the farm or working as hired laborers on-site at the time of the visit. The transition characteristics of agricultural landscape patterns as represented in abandoned, degraded farmlands and orchards are analyzed from a local perspective.

The conservation island effect of commercial hunting of red-legged partridges (Alectoris rufa) in agricultural landscapes

The conservation island effect of commercial hunting of red-legged partridges (Alectoris rufa) in agricultural landscapes

Assessment of agroclimatic resources in agricultural landscapes of the Turkestan region of the Republic of Kazakhstan Askha

The article presents the scientific results of a study assessing agroclimatic resources in agricultural landscapes located in various natural zones of the Turkestan region of the RK (Republic of Kazakhstan). The research methods included classical and modern methods of mathematical statistics using digital technology and time series graphs to develop a mathematical model for climatic and hydrological indicators. Assessment of changes in indicators of agroclimatic resources in agricultural landscapes for 1941–2020 showed that the sum of air temperature, evaporation from the water surface and radiation balance of the daytime surface, characterising the energy resources of landscapes, increased by 10–15%, which contributes to increase in the total water consumption of agricultural land by 10–12%. Meanwhile, the decreasing tendency of the amount of precipitation by 5–10% in all natural climatic zones of the region has become one of the factors leading to a decrease in the natural moisture supply of the soil and vegetation cover of landscapes by 10–15%, acting as important environment-forming and ecological functions. The combined impact of these environment-forming factors has become the key reason for the increase in the deficit of agricultural land water consumption by 15–20%, the reduction of solar energy costs for the soil-forming process by 10–15% and the increase of the climate aridisation, and has become a signal for the need in the safety of agricultural activities, requiring the development of a set of adaptive measures to mitigate this process in the region.

Infiltration Characteristics and Hydrodynamic Parameters in Response to Topographic Factors in Bare Soil Surfaces, Laboratory Experiments Based on Cropland Fields of Purple Soil in Southwest China

Topography is an important factor that impacts the hydrological processes on sloping farmlands. Yet, few studies have reported the combined influences of slope gradient and slope position on infiltration characteristics and hydrodynamic parameters on sloping croplands in purple soil regions, an important area for agricultural productivity in Southwest China. Here, laboratory-simulated rainfall experiments were conducted in a steel trough (5 m long, 2 m wide, and 0.45 m deep), and rainfall lasted for 1 h at a rate of 90 mm h−1 to examine the variations in the infiltration rates and hydrodynamic parameters under varying slope gradients (i.e., 3°, 6°, 10°, 15°, 21°, and 27°) and slope positions (i.e., upper, middle, and lower), and explore the relationships between the infiltration rate and the soil detachment rate. The results showed that the infiltration rate decreased gradually with duration rainfall and ultimately approached a steady state in the six slope treatments. Cumulative infiltration ranged from 15.54 to 39.32 mm during rainfall, and gradually reduced with the increase of slope gradient. The Horton’s model outperforms other models for predicting the infiltration rate with an R2 value of 0.86. Factors such as Darcy–Weisbach friction, flow shear force, Manning friction coefficient, unit energy, and runoff depth varied in the following order: upper slope > middle slope > lower slope, whilst the Reynolds number and Froude number gradually increased along the slope transect from the upper to lower slope positions. A significant linear function was fitted between the soil detachment rate and the infiltration rate at the gentle slopes (3°, 6°, 10°), whereas an exponential relationship was observed at the steep slopes (15°, 21°, and 27°). Observation also suggested that 15° was the critical slope gradient of sediment detachment, infiltration characteristics, and hydrodynamic parameters. Our results provide theoretical insight for developing models that predict the impacts of topographic factors on hydrological characteristic and soil erosion in hilly agricultural landscapes of purple soil fields.

Aohan Dryland agricultural landscape with an 8000-year history of foxtail millet cultivation in China

Aohan Dryland agricultural landscape with an 8000-year history of foxtail millet cultivation in China

Geochemistry of urban waters and their evolution within the urban landscape

Urban populations and the sprawl of urban environments are increasing in the United States as well as globally. The local hydrologic cycle is directly impacted by urban development through greater generation of surface runoff and export of water through subterranean pipes networks to surface water bodies. These pipe networks carry waters that have potentially dramatic effects on the chemistry of groundwater and surface water bodies. In this work, we sampled waters from the Olentangy River and two subterranean outfalls that flow into the river in Columbus, Ohio United States. We measured the major ion, nutrient, and dissolved silica concentrations of each water source to identify how the urban landscape impacts the chemistry of a river that travels from an agricultural landscape to an urban environment. The outfalls had elevated concentrations of all major ions (Na+, K+, Mg2+, Ca2+, Cl−, SO42-) and H4SiO4. However, the Olentangy river typically had greater NO3− and soluble reactive phosphorus (SRP) concentrations. Sources of elevated ion export include road salts and combined storm runoff (Na+, Cl−), municipal water treatment practices (K+, Na+, SO42-), and concrete pipe weathering (Ca2+, Mg2+, K+, H4SiO4, SO42-). Utilizing stable isotopes of water, δ18O and δ2H, we identified that the water in the pipe networks is typically a mix of multiple precipitation events, but there is evidence of flushing following high-volume precipitation events. The contribution of high TDS waters from subterranean urban outfalls modified the ion abundance in the Olentangy river and produces a tendency towards freshwater salinization syndrome. This is particularly apparent when comparing the chemistry of the urban Olentangy to the agricultural corridor of the river and its other source waters. This research details the transformation of a river as it flows from an agricultural to urban landscape and provides data on the chemistry of source waters that facilitate the river’s chemical changes.

Character and Evolution of Sunken Groundwater-Harvesting Agroecosystems in Aeolian Sand since Early Islamic Times, between Iran and Iberia

ABSTRACT By reviewing traditional, sunken, groundwater-harvesting agroecosystems (SGHAS) in coastal and inland aeolian sand situated in Iran, Egypt, Gaza Strip, Algeria and Iberia, coupled with image interpretation and geospatial analysis, we study the innovation and function of recently excavated Early Islamic (EI; tenth-twelfth century), Plot-and-Berm agroecosystems along the southeastern Mediterranean coast of Israel. The SGHAS and EI agroecosystems, usually affiliated with nearby towns, possess an aeolian sand substrate enrichened with urban refuse and/or organic material. The long-term investment in SGHAS attained profitable water security in the form of temporally continuous, shallow groundwater, replenished by rainfall. The crops in SGHASs include a wide range of vegetables, watermelons, dates and grapes, implying that the EI crops were partly or fully different. The spotty, historic appearance of SGHAS since the fifteenth–sixteenth centuries temporally lags after the abandonment of the EI agroecosystems, does not support spatial and temporal connectivity of sand agriculture knowledge, but probably exemplifies the appearance of site-specific ingenuities derived from growing agro-technological knowledge, crop variety and needs for food security. This study demonstrates the importance of traditional analogues for interpreting research gaps of archaeological, agricultural landscapes and provides insight for establishing traditionally-based, sustainable agriculture in sand.

Non‐native invasive plants in tropical dry forests: a global review of presence, impacts, and management

Tropical dry forests (TDF) are among the most‐threatened terrestrial ecosystems, experiencing ongoing conversion to agricultural fields, pasture, and human settlements. Human disturbances are often precursors to invasion of ecosystems by non‐native species, but research on invasion patterns in tropical ecosystems is sparse, and there is no comprehensive synthesis of invasive species in TDF. We conducted a review of published scientific literature to catalog and synthesize information about invasion by non‐native plants in TDF ecosystems across the globe, drawing out patterns in the invasion of these ecosystems. We found that 130 invasive plant species were documented as present in TDF, but only 25 of these species were mentioned in three or more articles. Almost all 25 of these more‐studied invasive species—mostly pasture grasses, woody legumes, and climbers—have been intentionally cultivated for agricultural or ornamental purposes. Many of these plants are native to open‐canopy savanna or forest edge habitats and benefit from human‐altered disturbance regimes (burning, grazing, and fuelwood and timber harvesting) of TDF fragments within agricultural landscapes. Field studies show that management approaches incorporating invasive removal, native plantings, and reduction in agricultural disturbance (e.g. ungulate fencing and fire control) simultaneously are often the most successful at reducing invasive plant cover. However, management studies in TDF have focused on a limited number of invasive species, and most were conducted in India and Hawaii. Global differences in TDF soils, natural fire regimes, and historic and current land use by humans influence modern biogeographic patterns of invasion and the feasibility of restoration options.

Modelling agricultural landscape complementation for natural pest control

Abstract Pest‐regulating natural enemies often require crop and non‐crop habitats to persist and be effective. These habitats offer hibernation sites, alternative prey or floral resources but can also be complementary in when they provide resources. The relative contribution of these different habitats to the performance of pest‐regulating insects is largely unknown, since it is difficult to study empirically. Landscape‐based population‐dynamical modelling can fill this research gap. In this study, we modelled the dynamics of predatory hoverflies (Diptera: Syrphinae) and their aphid prey in a collection of habitats. These hoverflies are dependent on different habitats for different reasons. While their larvae predate on aphids, adult hoverflies require floral resources. Resources are often segregated in different habitats. In addition, they are only temporarily available in any habitat type. In our model, hoverflies move between different habitats and select where to feed and where to produce off‐spring based on optimal foraging considerations. The model represents habitats common in arable landscapes and their temporal availability of resources is parameterized based on field observations. The model shows that effective pest suppression will only occur in the presence of at least three different habitats, including two crops that provide prey resources at different times of the year. A woody habitat with shrubs and trees provide aphid prey very early and late in the season, whereas an early crop and a late crop cover the period in between. In addition, these habitats need to provide floral resources in the same period as aphids, for example by flower strips in the margins of crop fields or blossoming trees or shrubs in the woody habitat. Under the model assumptions, the best pest suppression is obtained when the woody habitats take up 6% to 10% of the landscape. In addition to yearly population fluctuations, also bi‐ or multi‐yearly cycles may occur, depending on the composition of the landscape. Synthesis and applications. Our model shows when an agricultural landscape is ‘complete’ for natural enemies (and for effective pest control). For this, it needs to contain multiple habitats that supply floral and prey resources in different periods of the year.

Advancements in smart agriculture through innovative weed management using wavelet-based convolution neural network

Smart agriculture has shifted the paradigm by integrating advanced technologies, particularly weed management. This paper introduces an innovative approach to weed control by applying a Wavelet-based Convolution Neural Network (WCNN). In the era of precision agriculture, our study explores the integration of WCNN into real-world scenarios, emphasizing its adaptability to diverse environmental conditions. Utilizing the spatial-frequency analysis features of wavelets and convolutional neural networks, the WCNN model is the most effective at finding weeds, classifying them, and managing them specifically in agricultural fields in real-time. This research contributes to the scientific discourse on smart agriculture and addresses the challenges of invasive weeds, presenting a sustainable solution for optimizing resource utilization. Our investigation includes a detailed exploration of WCNN’s adaptive learning mechanisms and dynamic adjustment to changing agricultural landscapes. The model seamlessly integrates with existing smart farming infrastructure, showcasing a substantial reduction in manual intervention and a simultaneous increase in agricultural productivity. We incorporate fog computing and resource optimization into our framework, enhancing the efficiency of onboard data processing. To evaluate the real-world efficacy of WCNN, we conducted comprehensive experiments in texture classification and image labelling using two distinct datasets: the plant seedling and soybean weed datasets. Results demonstrate the superior performance of WCNN, achieving higher accuracy in training and test scenarios with significantly fewer parameters than traditional CNNs. For the soybean weed dataset, WCNN achieved remarkable accuracy in the training (0.9970) and testing (0.9987) phases, with correspondingly low losses of 0.0109 and 0.0048. The WCNN model demonstrated high accuracy during training (0.9739) and testing (0.9902), with minimal losses of 0.0898 and 0.0239 in the plant seedling dataset.

Agricultural Land Use Mapping Analysis Using the Geographic Information System in Temu Village

The agricultural sector remains a significant source of income for the people of East Sumba, particularly in Temu Village, Kanatang District, which spans 46.50 km². In Temu Village, a large portion of the population engages in farming and gardening, utilizing agricultural land that includes rice fields, fields, and plantations. Analyzing the current use of this land is crucial for predicting agricultural yields and proposing optimal land use strategies to ensure sufficient local food production. However, the distribution of agricultural land has not been thoroughly mapped, leaving gaps in information regarding the location and potential of these lands. This research aims to map the agricultural potential of Temu Village using Geographic Information System (GIS) technology through overlay and scoring methods, resulting in informative land use maps. The findings reveal that fields dominate the agricultural landscape with 1.648903 km² or 81.10% of the total agricultural land, highlighting the primary focus on field crops. Rice fields cover 0.270512 km² or 13.30%, while gardens occupy the smallest area of 0.113825 km² or 5.60%. These results demonstrate the potential for effective geographical management of plantations, rice fields, and agricultural fields based on their respective areas.

Barn owl site occupancy and breeding success in relation to land use and nest box characteristics

AbstractAgricultural landscapes play a crucial role in enhancing biodiversity because of their widespread presence over the Earth and their ability to encompass diverse ecosystems. Recognizing this, numerous governments are incentivizing farmers through direct payments to adopt sustainable practices, such as managing extensive pastures and meadows, planting wildflowers, or establishing hedgerows. However, the benefit of such sustainable practices on vertebrate species is not well understood. From 2018 to 2020, we investigated nest occupancy, fledging success, and clutch size of a Swiss population of barn owls (Tyto alba) with respect to nest box characteristics and the presence of extensive agriculture and urbanization in areas surrounding nest boxes. Our results revealed that extensively used pastures were positively associated with site occupancy but negatively associated with clutch size. The proportion of urban areas was negatively related to both site occupancy and clutch size. The altitude of the nest box location was negatively correlated with occupancy, and the number of nest boxes placed at the same site (either 1 or 2) was positively correlated with site occupancy. Moreover, clutch size, but not fledging success, was larger in nest boxes placed outside barns than in nest boxes placed inside barns. Based on these findings, we recommend installing nest boxes at locations <700 m in altitude and in pairs on the same barn, incorporating biodiversity promotion areas into agricultural landscapes, and avoiding dense urban areas in favor of rural zones with lower urban density. Understanding the nuanced relationships between nest box characteristics, environmental factors, and breeding success provides valuable insights for optimizing artificial nesting sites and enhancing the overall reproductive success of barn owls.

Multi-Annual Study of Eriogaster catax (Linnaeus, 1758) (Lepidoptera, Lasiocampidae) Oviposition Strategy in Transylvania's Largest Population: Key Insights for Species Conservation and Local Land Management.

This study provides new insights into the oviposition strategy of Eriogaster catax (Linnaeus, 1758) (Lepidoptera, Lasiocampidae), an endangered species of moth found in semi-natural habitats within agricultural landscapes. Protected under various European directives and listed as Data Deficient by the IUCN, E. catax inhabits warmer regions of the Western Palearctic. Despite noted geographic variations in its ecological preferences, few studies have statistically significant data on its ecology. Our six-year study, conducted within the largest known population of E. catax. in Romania, reveals critical data on its oviposition preferences, including the species' tendency to utilize Prunus spinosa L. and Crataegus monogyna Jacq. shrubs at an average height of 80.48 ± 34.3 cm, with most nests placed within the 41-80 cm range and containing an average of 186 ± 22 eggs. The study also addresses the species' vulnerability to human activities such as bush trimming, agricultural burning, and uncontrolled grazing, particularly due to its low oviposition height. These findings underscore the negative impact of overgrazing and burning practices, particularly when conducted on a large scale, on the conservation of E. catax. The detailed ecological requirements identified in this study are essential for developing effective conservation strategies and habitat management practices. Furthermore, the study highlights the importance of local community involvement and public education in raising awareness about biodiversity and the conservation of endangered species.

The impact of technologies for the development and use of virgin, fallow lands on agroecological stability and soil fertility

Relevance. The research was carried out in order to analyze the impact of technologies for the development of virgin and fallow lands on erosion processes in the steppe zone in the 60s and modern conditions.Methods. The analysis of approaches to the prevention of soil degradation and desertification of the territory is carried out based on materials obtained in the steppe zone of the Republic of Khakassia in the second half of the XX century and in modern conditions. We used the results of the application of technologies for the development of virgin and fallow lands of Tselinnoye LLC in different periods. Information about dust storms was taken from data from the Bey and Shire weather stations. In 1954–1960 when plowing the chernozem of the southern virgin lands, technology was used using plows, huskers and other tillage tools. The lack of adapted ways of developing and using new lands has led to an outbreak of wind erosion of soils over large areas, including in the south-east of the country.Results. The dump system of soil treatment during the mass development of virgin and fallow lands in the 60s, without taking into account soil, climatic and other conditions, led to a strong development of wind erosion. The number of days with dust storms in Khakassia reached up to 4.8–11.6 per year. In modern conditions, the removal of highly ventilated soils from arable lands and the use of strip placement of crops and minimal tillage on the rest of the arable land contribute to increasing the erosion resistance of agricultural landscapes. The use of the Tornado 500 herbicide in August during the development of the deposit reduces the erodibility by 2.5 times, compared with the technology with its introduction in early summer.

A landscape-based approach to design flower blocks may reduce mammalian predator activity and protect ground-nesting farmland birds

AbstractHigh predation rates threaten many ground-nesting farmland birds and are difficult to address through conventional measures such as lethal predator control or fencing. Landscape-based approaches for conservation measures promise an alternative by reducing predator - bird encounters, but require detailed knowledge of landscape effects on predation risk. Different habitat elements attractive to predators could have opposing effects on neighbouring nesting habitats, with implications for conservation: Increased predation risk due to higher predator activity (A) or reduced predation risk by distracting predators (B). Here we focus on the placement of conservation measures using flower blocks targeted at Grey Partridges in a Central European Farmland. Based on a three-year camera trap dataset, we investigated effects of landscape structure and composition on mammalian predator activity within flower blocks at two scales (100 m and 500 m radius around the camera) with generalized linear mixed models. Length of linear edge structures, i.e., field block borders, was most important, with a greater availability of linear edge structures leading to a decrease in predator activity at both scales (hypothesis B). Conversely, predator captures at both scales increased with increasing extensive vegetation area (i.e., permanent grassland, flower blocks and fallows) and in proximity to roads, indicating that these may attract predators and increase predator densities (hypothesis A). Our results suggest that a landscape-based approach can mitigate predation risk for ground-nesting birds in flower blocks and analogous conservation measures. Highly structured, small-scale agricultural landscapes seem to be particularly important for reducing mammalian predator activity in flower blocks.

Potential phosphorus mobilization from riparian vegetation following freezing

Phosphorus (P) rich runoff from agricultural landscapes is a major contributor to freshwater eutrophication. Vegetated riparian zones are often employed to retain P from field runoff before it enters streams. In cold regions, vegetation has the potential to release P to runoff following freezing; however, it is unclear if this differs with winter frost severity, riparian zone local topography, vegetation type, and/or exposure to flooding/inundation. To explore the vulnerability of riparian vegetation to winter P losses, this study quantified soil and vegetation P concentrations from 8 riparian zones in Canada at different topographic positions within each riparian site (upper/field edge, lower/water edge) in both the fall and spring seasons and related this to observed surface temperatures and water levels throughout the non-growing season. This was complemented by two laboratory mesocosm experiments in which (1) plant samples were subjected to moderate (−40C) and severe (−250C) simulated winter frost treatments to quantify changes in their water extractable P (WEP) content, and (2) mesocosms were inundated with water to determine if dissolved P concentrations in flood water differed when plants were left intact, clipped but left on the soil surface, or harvested. Greater soil and vegetation P concentrations were observed at upper locations (field edge), and this remained consistent following freezing; however, vegetation WEP concentrations increased with greater simulated frost severity. In the field, temperatures were moderated by snow cover and although differences with riparian zone position were apparent between fall and spring collected samples, changes in P pools did not appear to be related to frost severity or inundation in the field. The mesocosm experiment revealed that harvesting vegetation considerably reduced dissolved P concentrations in flood water. This study shows that vegetated riparian zones can act as a source of P to streams during the winter non-growing season, and highlights the potential for riparian vegetation management in reducing P losses from riparian zones in cold climates.