Changes In Land Management Practices Research Articles

Spatiotemporal variation and controlling factors of dried soil layers in a semi-humid catchment and relevant land use management implications

The formation of dried soil layers (DSLs) is a broad consequence of climate change (i.e., through temperature increases and/or precipitation decreases) and poor land management practices, where these layers exist has severe negative effects (i.e., retardation of vegetation, negative water cycle balance) on the sustainability of restored ecosystems and health of agriculture. Because of the effort and time required, only sporadic in situ measurements on spatial and temporal DSL variation have been reported, particularly at a catchment scale. However, this information is essential for understanding mechanisms associated with evolutionary DSL processes as well as developing effective land management techniques. Accordingly, this study monitored soil water content to a 5 m depth over a 5-year period in a semi-humid catchment on the Loess Plateau while also investigating temporal DSL dynamics and dominant controls. In the semi-humid catchment, DSLs occurred at 90.7 % of all sampling sites. Spatially and temporally averaged DSL formation depth (DSLFD), DSL thickness (DSLT), and DSL soil water content (DSL-SWC) within the 0–5 m profile were 170 cm, 262 cm, and 9.52 %, respectively. Forest and shrubland DSL regimes were drier than those of grassland. These three DSL indices exhibited significant correlation with temperature variables, while only DSLFD variables significantly correlated to precipitation. Land use type was the predominant control of DSL variation at a catchment scale. A spatial DSLT variation comparison under different land use treatment positions determined the feasibility of planting grass at an upslope position and mixed forest/shrubland + grass at mid-slope and downslope positions in the semi-humid catchment, which provides a good case study for afforestation practices at a catchment scale. Findings from this study are intended to aid in catchment soil and water conservation, soil drought mitigation, and sustainable vegetation management practices on the Loess Plateau as well as other water-limited regions worldwide.

An invisible water surcharge: Climate warming increases crop water demand in the San Joaquin Valley’s groundwater-dependent irrigated agriculture

California’s bountiful San Joaquin Valley (SJV), a critical region for global fruit and nut production, has withstood two severe, multi-year droughts in the past decade, exacerbated by record-breaking high temperature and evaporative demand. We employed climate data and crop coefficients to estimate the crop water demand in the SJV over the past forty years. Our approach, using crop coefficients for Penman-Montieth modeled evapotranspiration, focused on the climate effects on crop water demand, avoiding the confounding factors of changing land use and management practices that are present in actual evapotranspiration. We demonstrate that increases in crop water demand explain half of the cumulative deficits of the agricultural water balance since 1980, exacerbating water reliance on depleting groundwater supplies and fluctuating surface water imports. We call this phenomenon of climate-induced increased crop water demand an invisible water surcharge. We found that in the past decade, this invisible water surcharge on agriculture has increased the crop water demand in the SJV by 4.4% with respect to the 1980–2011 timeframe—more than 800 GL per year, a volume as large as a major reservoir in the SJV. Despite potential agronomic adaptation and crop response to climate warming, increased crop water demand adds a stressor to the sustainability of the global fruit and nut supply and calls for changes in management and policies to consider the shifting hydroclimate.

Stability of soil bacteria in undisturbed soil and continuous maize cultivation in Northern Thailand.

Rotational shifting cultivation (RSC) in Northern Thailand serves the dual purpose of ensuring food security and meeting economic goals through maize cultivation. However, the research question remains: Does the dynamics of soil bacterial communities differ between maize monoculture and RSC fields with continuous fallow throughout the season? Therefore, the objective of this study was to investigate and compare the variation of soil bacterial communities in maize monoculture and fallow RSC fields. A continuous 5-year fallow field (undisturbed soil; CF-5Y) and a continuous 5-year maize cultivation field (M-5Y) in Mae Chaem District, Chiang Mai Province, Northern Thailand, were selected due to their similarities in microclimate, topography, and the 5-year duration of different field activities. Over the span of a year, we collected soil samples from the surface layer (0-2 cm depth) at both sites. These collections occurred at 3-month intervals, starting from March 2022 (summer season) and followed by June (rainy season), September (rainy season), December (winter season), and March 2023 (summer season). Soil bacterial diversity and composition were analyzed using 16S rRNA gene-based metagenomic analysis. The results found that undisturbed soil over a 5-year period exhibited more stability in the richness and diversity of bacteria across seasons compared with M-5Y. Notably, fertilizer application and tillage practices in M-5Y can enhance both the diversity and richness of soil bacteria. In terms of bacterial abundance, Proteobacteria prevailed in CF-5Y, while Actinobacteria dominated in M-5Y. At the genus level, Candidatus Udaeobacter dominated during the summer and winter seasons in both CF-5Y and M-5Y sites. Interestingly, during the rainy season, the dominant genus shifted to Bacillus in both CF-5Y and M-5Y fields. The soil bacterial community in M-5Y was strongly influenced by organic matter (OM) and organic carbon (OC). In contrast, in CF-5Y, there was no correlation between soil properties and the soil bacterial community, likely due to the lower variation in soil properties across seasons. β-Glucosidase was the dominant enzyme in both CF-5Y and M-5Y sites, and it showed a positive correlation with OM and OC. Further studies should continue to investigate soil bacteria dynamics, considering the changes in land management practices.

Linking Soil Structure, Hydraulic Properties, and Organic Carbon Dynamics: A Holistic Framework to Study the Impact of Climate Change and Land Management

AbstractClimate change and unsustainable land management practices have resulted in extensive soil degradation, including alteration of soil structure (i.e., aggregate and pore size distributions), loss of soil organic carbon, and reduction of water and nutrient holding capacities. Although soil structure, hydrologic processes, and biogeochemical fluxes are tightly linked, their interaction is often unaccounted for in current ecohydrological, hydrological and terrestrial biosphere models. For more holistic predictions of soil hydrological and biogeochemical cycles, models need to incorporate soil structure and macroporosity dynamics, whether in a natural or agricultural ecosystem. Here, we present a theoretical framework that couples soil hydrologic processes and soil microbial activity to soil organic carbon dynamics through the dynamics of soil structure. In particular, we link the Millennial model for soil carbon dynamics, which explicitly models the formation and breakdown of soil aggregates, to a recent parameterization of the soil water retention and hydraulic conductivity curves and to solute and O2 diffusivities to soil microsites based on soil macroporosity. To illustrate the significance of incorporating the dynamics of soil structure, we apply the framework to a case study in which soil and vegetation recover over time from agricultural practices. The new framework enables more holistic predictions of the effects of climate change and land management practices on coupled soil hydrological and biogeochemical cycles.

Changes in land management practices have reduced wind erosion in the cropping areas of far south-western NSW, Australia

Since the mid-1970s, approximately 250 000 ha of rangelands in semi-arid far south-western NSW, Australia, have been converted to cropping land use, resulting in substantial wind erosion. Wind erosion is of concern because of its adverse impacts on soils, agricultural production, aviation, energy supply, human health and ecosystem function. Over recent decades, multi-faceted extension programs have promoted sustainable land management practices to reduce wind erosion. Repeated biannual paddock surveys were undertaken between 2003 and 2022 to determine (1) the best land management practices (BMPs), that is, those that would reduce erosion while maintaining productivity and profitability, and (2) whether the use of the BMPs changed over time. The BMPs that reduce wind erosion included chemical fallow, standing stubble, and perennial pastures. Between 2003 and 2022, the proportion of sites with BMPs increased from 14% to 75%, and the proportion of sites with wind erosion fell from 23% to 9%. Practices that reduced ground cover and led to frequent erosion have declined, including tilled pasture, tilled stubble and grazed stubble. In drier years, livestock grazing crop stubble exacerbated the erosion hazard. In an attempt to understand where landholders obtain their information for land management practice change, the Western Local Land Services (LLS) conducted a social benchmarking survey in 2020 that indicated that the LLS was the third source of information for practice change after neighbours and other landholders, and stock and station agents. Although the LLS is a source of information, this study could not determine a causal link between LLS programs and practice change. Further research is required to test whether extension programs can reduce the overgrazing of stubble.

Assessing Future Water Allocation under Climate Variability and Land Management Change in an Agricultural Watershed

ABSTRACTClimate change and population growth are increasing demand for water, causing water shortages across the United States. Decision makers need to understand the impact of climate on water allocation, particularly for watersheds with agricultural activity. The Missouri Salt River Basin (SRB) was selected for this study due to its soil characteristics, agriculturally dominated land use, and because it contains a major reservoir, Mark Twain Lake (MTL), which is the regional source of drinking water. The goal was to evaluate future water allocation in the SRB given projections of future climate and changing land management practices. Future climate data were input to the Soil and Water Assessment Tool, from which discharge outputs to MTL were entered in the Water Evaluation and Planning model to evaluate 2020–2059 crop and drinking water shortages. Water allocation strategies identified potential conflicts among users through scenario‐based approaches. The difference between water demand and supply was projected to increase by 100% because of climate change, from 3 to 6 million m3. Under a dramatic scenario, where irrigated land quadrupled, water shortage could be up to 38.5 million m3 (1,200% increase). Water withdrawals from the MTL may help alleviate part of the projected shortage; however, on‐farm pond storage would likely be more practical and cost‐effective. Overall, the paper provides a methodology for water allocation strategy.

How do large wildfires impact sediment redistribution over multiple decades?

AbstractWildfires have become an increasing threat for Mediterranean ecosystems, due to increasing climate change‐induced wildfire activity and changing land management practices. In addition to the initial risk, wildfires can alter the soil in various ways—depending on fire severity—and cause enhanced post‐fire erosion. Usually, post‐fire erosion studies focus on a short time window and lack the attention for sediment dynamics at larger spatial scales. Yet, these large spatial and temporal scales are fundamental for a better understanding of long‐term destructive effects of multiple recurring wildfires on post‐fire erosion processes and catchment sediment dynamics. In this study the landscape evolution model LAPSUS was used to simulate erosion and deposition in the 404 km2 Águeda catchment in north‐central Portugal over a 41‐year (1979–2020) timespan, including eight wildfires each burning >1000 ha. To include variation in fire severity and its impact on the soil, four burn severity classes, represented by the difference normalized burn ratio (dNBR), were parameterized. Although model calibration was difficult due to lack of spatial and temporal measured data, the results show that long‐term post‐fire net erosion rates were significantly higher in the wildfire scenarios (5.95 ton ha−1 yr−1) compared to those of a non‐wildfire scenario (0.58 ton ha−1 yr−1). Furthermore, erosion values increased with burn severity and multiple wildfires increased the overall catchment sediment build‐up. Simulated erosion patterns showed great spatial variability, with large deposition and erosion rates inside streams. This variability made it difficult to identify land uses that were most sensitive for post‐fire erosion, because some land uses were located in more erosion‐sensitive areas (e.g. streams, gullies) or were more affected by high burn severity levels than others. Despite these limitations, LAPSUS performed well on addressing spatial sediment processes and can contribute to pre‐fire management strategies, by identifying locations at risk of post‐fire erosion.

SOILomics; where Microbiome Genetics meets Precision Agriculture

Advances in genetics, soil biochemistry and microbiome analysis are opening up a new era in Precision Agriculture. In this direction, new techniques bring groundbreaking changes in land management practices through direct or indirect management of soil microbial communities. There is huge demand for the protection and enhancement of soil health and climate change resilience of crops. The increase in population, food consumption and fast approaching climate change pose a new threat to mankind that only by being proactive and highly prepared to deploy all novel and innovative stratagems in state-of-the-art soil microbiome precision agriculture can be avoided.

Changing soil organic carbon with land use and management practices in a thousand-year cultivation region

Soil organic carbon (SOC) is a critical mass of global terrestrial carbon store that can be altered by land use and land management practices. As an important grain production area in the Yellow River basin, there have been intensive agricultural activities in the Guanzhong Plain for over 1000 years. The conversion of cropland into orchard and changes in land management practices could have altered the distribution and amount of SOC stores in the region. To determine spatial variations in SOC and its response to changes in land use and land management practices in the thousand-year cultivated region, SOC content was measured at 127 sites, including 117 sites in the 0–100 cm soil layer and 10 sites in the 0–1000 cm soil layer. The results showed a pronounced decline in SOC content with increasing depth in the upper 100 cm soil layer, whereas it was relatively low and stable in deeper soil layers. SOC stock in the 0–100 and 100–1000 cm soil layers accounted for 16.9% and 83.1%, respectively, of the total SOC stock in the 0–1000 cm soil profile. Compared with the 1980s, mean SOC stock in the 0–100 cm soil layer significantly increased (by 0.69 kg m−2) over the 40-year period. Furthermore, no significant difference was observed in SOC content between cropland and orchard land soils for both the 0–100 and 100–1000 cm soil layers. Land management practices (irrigation and fertilization), climatic variables (precipitation and temperature), and soil properties (pH and clay content) together influenced the spatial variations in SOC in the 0–60 cm soil depth. However, variations were dominantly driven by soil properties at depths below 60 cm. Therefore, while SOC in layers below 100 cm was critical for carbon budget estimations, SOC was not altered by changes in agricultural land use in both the shallow and deep soils of the study area. Agricultural management practices, soil properties, and organic carbon storage in deep soils need to be considered in future carbon budget studies in cultivated lands, especially in regions with deep soils.

SOILomics; where Microbiome Genetics meets Precision Agriculture

Advances in genetics, soil biochemistry and microbiome analysis are opening up a new era in Precision Agriculture. In this direction, new techniques bring groundbreaking changes in land management practices through direct or indirect management of soil microbial communities. There is huge demand for the protection and enhancement of soil health and climate change resilience of crops. The increase in population, food consumption and fast approaching climate change pose a new threat to mankind that only by being proactive and highly prepared to deploy all novel and innovative stratagems in state-of-the-art soil microbiome precision agriculture can be avoided.

Climate More Important for Chinese Flood Changes Than Reservoirs and Land Use

AbstractRiver regulations and changing land management practices are generally perceived to be the dominant drivers of river flood changes in countries with rapid economic growth, such as China. Here, we demonstrate based on the most comprehensive flood database to date, that climate variations dominate the spatial pattern of changes in annual flood peak discharge in China, despite intense human alterations of the river and land systems over the past four decades. Regional flood increases are mainly associated with increasing precipitation due to changes in the East Asian Summer Monsoon, tropical cyclones and the subtropical westerly jet. Regional flood decreases are due to decreased soil moisture in the North China plain. Our results highlight the need for flood management policies to go beyond local measures and adapt to the effects of climate change.

Challenges and prospects of climate change and agricultural land management practices in Ben Seshangul Gomez region Asosa zone, north west, Ethiopia

Challenges and prospects of climate change and agricultural land management practices in Ben Seshangul Gomez region Asosa zone, north west, Ethiopia

The Sentinel-3 OLCI Terrestrial Chlorophyll Index (OTCI): Algorithm Improvements, Spatiotemporal Consistency and Continuity with the MERIS Archive

The Ocean and Land Colour Instrument (OLCI) on-board Sentinel-3 (2016–present) was designed with similar mechanical and optical characteristics to the Envisat Medium Resolution Imaging Spectrometer (MERIS) (2002–2012) to ensure continuity with a number of land and marine biophysical products. The Sentinel-3 OLCI Terrestrial Chlorophyll Index (OTCI) is an indicator of canopy chlorophyll content and is intended to continue the legacy of the Envisat MERIS Terrestrial Chlorophyll Index (MTCI). Despite spectral similarities, validation and verification of consistency is essential to inform the user community about the product’s accuracy, uncertainty, and fitness for purpose. This paper aims to: (i) describe the theoretical basis of the Sentinel-3 OTCI and (ii) evaluate the spatiotemporal consistency between the Sentinel-3 OTCI and the Envisat MTCI. Two approaches were used to conduct the evaluation. Firstly, agreement between the Sentinel-3 OTCI and the Envisat MTCI archive was assessed over the Committee for Earth Observation Satellites (CEOS) Land Product Validation (LPV) core validation sites, enabling the temporal consistency of the two products to be investigated. Secondly, intercomparison of monthly Level-3 Sentinel-3 OTCI and Envisat MTCI composites was carried out to evaluate the spatial distribution of differences across the globe. In both cases, the agreement was quantified with statistical metrics (R2, NRMSD, bias) using an Envisat MTCI climatology based on the MERIS archive as the reference. Our results demonstrate strong agreement between the products. Specifically, high 1:1 correspondence (R2 >0.88), low global mean percentage difference (−1.86 to 0.61), low absolute bias (<0.1), and minimal error (NRMSD ~0.1) are observed. The temporal profiles reveal consistency in the expected range of values, amplitudes, and seasonal trajectories. Biases and discrepancies may be attributed to changes in land management practices, land cover change, and extreme climatic events occurred during the time gap between the missions; however, this requires further investigation. This research confirms that Sentinel-3 OTCI dataset can be used along with the Envisat MTCI to provide a data coverage over the last 20 years.

Earthworm abundance and functional group diversity regulate plant litter decay and soil organic carbon level: A global meta-analysis

A previous review of earthworm impacts on greenhouse-gas emissions concluded that earthworms elevated soil CO2 emissions with no apparent influence on soil organic carbon (SOC), especially in laboratory incubations and in agroecosystems. This conclusion suggests that the elevated soil CO2 emissions may come from enhanced plant litter decomposition. Despite the known important role of earthworms on regulating ecosystem processes, a quantitative analysis of the relationship between earthworms and decomposition in global terrestrial ecosystems is still missing. Here, we present a quantitative synthesis of earthworm effects on plant litter decomposition and SOC based on 340 observations from 69 independent studies. We found a positive correlation between earthworm density and the rate of plant litter decay, and that the presence of earthworms doubled the amount of litter mass loss on average. The presence of all three (anecic, epigeic and endogeic) earthworm functional groups was associated with higher litter mass loss than when either one or two functional groups were present. Anecic earthworms caused the strongest effect on litter mass loss, followed by epigeic earthworms, and there was no apparent influence by endogeic worms. Although the effect of earthworms on SOC was not significant based on all observations, the presence of any two of the three functional groups alone or two (epigeic and endogeic, or anecic and endogeic) and three (anecic, epigeic and endogeic) functional groups together decreased SOC concentrations. Our results indicate that the effect of earthworms on litter and SOC decay depends strongly on earthworm functional groups and diversity, and that a high diversity of earthworm functional groups accelerates litter mass loss and SOC decay. We anticipate that changes in land management practices are likely to alter ecosystem carbon cycling through alteration of earthworm abundance and diversity.

Projections of declining fluvial sediment delivery to major deltas worldwide in response to climate change and anthropogenic stress

Deltas are resource rich, low-lying areas where vulnerability to flooding is exacerbated by natural and anthropogenically induced subsidence and geocentric sea-level rise, threatening the large populations often found in these settings. Delta ‘drowning’ is potentially offset by deposition of sediment on the delta surface, making the delivery of fluvial sediment to the delta a key balancing control in offsetting relative sea-level rise, provided that sediment can be dispersed across the subaerial delta. Here we analyse projected changes in fluvial sediment flux over the 21st century to 47 of the world’s major deltas under 12 environmental change scenarios. The 12 scenarios were constructed using four climate pathways (Representative Concentration Pathways 2.6, 4.5, 6.0 and 8.5), three socioeconomic pathways (Shared Socioeconomic Pathways 1, 2 and 3), and one reservoir construction timeline. A majority (33/47) of the investigated deltas are projected to experience reductions in sediment flux by the end of the century, when considering the average of the scenarios, with mean and maximum declines of 38% and 83%, respectively, between 1990–2019 and 2070–2099. These declines are driven by the effects of anthropogenic activities (changing land management practices and dam construction) overwhelming the effects of future climate change. The results frame the extent and magnitude of future sustainability of major global deltas. They highlight the consequences of direct (e.g. damming) and indirect (e.g. climate change) alteration of fluvial sediment flux dynamics and stress the need for further in-depth analysis for individual deltas to aid in developing appropriate management measures.

Trends and indicators for quantifying moth abundance and occupancy in Scotland

Moths form an important part of Scotland’s biodiversity and an up-to-date assessment of their status is needed given their value as a diverse and species-rich taxon, with various ecosystem roles, and the known decline of moths within Britain. We use long-term citizen-science data to produce species-level trends and multi-species indicators for moths in Scotland, to assess population (abundance) and distribution (occupancy) changes. Abundance trends for moths in Scotland are produced using Rothamsted Insect Survey count data, and, for the first time, occupancy models are used to estimate occupancy trends for moths in Scotland, using opportunistic records from the National Moth Recording Scheme. Species-level trends are combined to produce abundance and occupancy indicators. The associated uncertainty is estimated using a parametric bootstrap approach, and comparisons are made with alternative published approaches. Overall moth abundance (based on 176 species) in Scotland decreased by 20% for 1975–2014 and by 46% for 1990–2014. The occupancy indicator (based on 230 species) showed a 16% increase for 1990–2014. Alternative methods produced similar indicators and conclusions, suggesting robustness of the results, although rare species may be under-represented in our analyses. Species abundance and occupancy trends were not clearly correlated; in particular species with negative population trends showed varied occupancy responses. Further research into the drivers of moth population changes is required, but increasing occupancy is likely to be driven by a warming summer climate facilitating range expansion, whereas population declines may be driven by reductions in habitat quality, changes in land management practices and warmer, wetter winters.

Characterizing grassland fire activity in the Flint Hills region and air quality using satellite and routine surface monitor data

Prescribed grassland fires in the Flint Hills region of central Kansas and northern Oklahoma are a common tool for land management. Local to regional scale impacts on air quality from grassland fires in this region are not well understood, which is important as these types of prescribed fires may increase in the future to preserve broader areas of native grasses in the central U.S. Routine air quality and deposition measurements from sites in and near the Flint Hills were examined for coincident increases during periods of increased prescribed grassland fires. Prescribed fire activity in this region was quantified using satellite detections and multiple publicly available data products of area burned information. March and April comprise over half (41 to 93%) of all annual fire detections in the Flint Hills region seen from satellites between 2007 and 2018 excluding drought years. Annual total fire detections in this region range between 1 and 12 thousand and account for approximately 3% of all fire detections in the contiguous U.S. Annual acres burned ranged from 0.2 to 2 million acres based on U.S. EPA's National Emission Inventory, which accounts for 4 to 38% of grasslands in the area. A comparison of weekly standardized anomalies suggests a relationship between periods of increased grassland fire activity and elevated levels of PM2.5 organic carbon, elemental carbon, and potassium. Daily 1-hr maximum ozone (O3), ammonia (NH3), sulfur dioxide (SO2), and oxidized nitrogen gases measured at Konza Prairie also had increased levels when prescribed grassland fire activity was highest. This detailed characterization of prescribed fire activity in the Flint Hills and associated air quality impacts will benefit future efforts to understand changes in atmospheric composition due to changing land management practices.

Mapping change in key soil properties due to climate change over south-eastern Australia

Climate change will lead to altered soil conditions that will impact on plant growth in both agricultural and native ecosystems. Additionally, changes in soil carbon storage will influence carbon accounting schemes that may play a role in climate change mitigation programs. We applied a digital soil mapping approach to examine and map (at 100-m resolution) potential changes in three important soil properties – soil organic carbon (SOC), pH and sum-of-bases (common macro-nutrients) – resulting from projected climate change over south-eastern Australia until ~2070. Four global climate models were downscaled with three regional models to give 12 climate models, which were used to derive changes for the three properties across the province, at 0–30 and 30–100 cm depth intervals. The SOC stocks were projected to decline over the province, while pH and sum-of-bases were projected to increase; however, the extent of change varied throughout the province and with different climate models. The average changes primarily reflected the complex interplay of changing temperatures and rainfall throughout the province. The changes were also influenced by the operating environmental conditions, with a uniform pattern of change particularly demonstrated for SOC over 36 combinations of current climate, parent material and land use. For example, the mean decline of SOC predicted for the upper depth interval was 15.6 Mg ha–1 for wet–mafic–native vegetation regimes but only 3.1 Mg ha–1 for dry–highly siliceous–cropping regimes. The predicted changes reflected only those attributable to the projected climate change and did not consider the influence of ongoing and changing land management practices.

Corrigendum to: Mapping change in key soil properties due to climate change over south-eastern Australia

Climate change will lead to altered soil conditions that will impact on plant growth in both agricultural and native ecosystems. Additionally, changes in soil carbon storage will influence carbon accounting schemes that may play a role in climate change mitigation programs. We applied a digital soil mapping approach to examine and map (at 100-m resolution) potential changes in three important soil properties – soil organic carbon (SOC), pH and sum-of-bases (common macro-nutrients) – resulting from projected climate change over south-eastern Australia until ~2070. Four global climate models were downscaled with three regional models to give 12 climate models, which were used to derive changes for the three properties across the province, at 0–30 and 30–100 cm depth intervals. The SOC stocks were projected to decline over the province, while pH and sum-of-bases were projected to increase; however, the extent of change varied throughout the province and with different climate models. The average changes primarily reflected the complex interplay of changing temperatures and rainfall throughout the province. The changes were also influenced by the operating environmental conditions, with a uniform pattern of change particularly demonstrated for SOC over 36 combinations of current climate, parent material and land use. For example, the mean decline of SOC predicted for the upper depth interval was 15.6 Mg ha–1 for wet–mafic–native vegetation regimes but only 3.1 Mg ha–1 for dry–highly siliceous–cropping regimes. The predicted changes reflected only those attributable to the projected climate change and did not consider the influence of ongoing and changing land management practices.

Application of high-resolution telemetered sensor technology to develop conceptual models of catchment hydrogeological processes

Mitigating agricultural water pollution requires changes in land management practices and the implementation of on-farm measures to tackle the principal reasons for water quality failure. However, a paucity of robust empirical evidence on the hydrological functioning of river catchments can be a major constraint on the design of effective pollution mitigation strategies at the catchment-scale. In this regard, in 2010 the UK government established the Demonstration Test Catchment (DTC) initiative to evaluate the extent to which on-farm mitigation measures can cost-effectively reduce the impacts of agricultural water pollution on river ecology while maintaining food production capacity. A central component of the DTC platform has been the establishment of a comprehensive network of automated, web-based sensor technologies to generate high-temporal resolution empirical datasets of surface water, soil water, groundwater and meteorological parameters. In this paper, we demonstrate how this high-resolution telemetry can be used to improve our understanding of hydrological functioning and the dynamics of pollutant mobilisation and transport under a range of hydrometerological and hydrogeological conditions. Furthermore, we demonstrate how these data can be used to develop conceptual models of catchment hydrogeological processes and consider the implications of variable hydrological functioning on the performance of land management changes aimed at reducing agricultural water pollution.