Historic record of pasture soil water and the influence of the North Atlantic Oscillation in south-west England

The North Wyke Farm Platform is a National Capability funded by the Biotechnology and Biological Sciences Research Council in the UK (project number BB/J004308/1). Climate data were measured at the MIDAS Land Surface Station DLY3208 DEVON, UK, a weather station of the UK Meteorological Office. We would especially like to thank Dr Melannie Hartmann, NREL, Colorado State University for the inclusion and use of the DayCent model, and advice on preparation of model parameters.Peer reviewedPublisher PD

Carbon Sequestration by Fruit Trees - Chinese Apple Orchards as an Example

Apple production systems are an important component in the Chinese agricultural sector with 1.99 million ha plantation. The orchards in China could play an important role in the carbon (C) cycle of terrestrial ecosystems and contribute to C sequestration. The carbon sequestration capability in apple orchards was analyzed through identifying a set of potential assessment factors and their weighting factors determined by a field model study and literature. The dynamics of the net C sink in apple orchards in China was estimated based on the apple orchard inventory data from 1990s and the capability analysis. The field study showed that the trees reached the peak of C sequestration capability when they were 18 years old, and then the capability began to decline with age. Carbon emission derived from management practices would not be compensated through C storage in apple trees before reaching the mature stage. The net C sink in apple orchards in China ranged from 14 to 32 Tg C, and C storage in biomass from 230 to 475 Tg C between 1990 and 2010. The estimated net C sequestration in Chinese apple orchards from 1990 to 2010 was equal to 4.5% of the total net C sink in the terrestrial ecosystems in China. Therefore, apple production systems can be potentially considered as C sinks excluding the energy associated with fruit production in addition to provide fruits

Modelling the Effect of Climate Change on Environmental Pollution Losses from Dairy Systems in the UK

21 p.So far, there has been strong emphasis on studying the impacts of climate change on agriculture in terms of changes in food production; however, there is increasing evidence that agricultural ecosystems (e.g. livestock) will also be severely affected in terms of other goods and services. For example, patterns and loads of environmental pollution derived from nutrient losses are expected to change dramatically (e.g. increased run-off: Betts et al., 2007). There have been few studies that use a system-based approach to explore the complex interactions between farm inputs, response of system components and inherent site factors that give rise to changes in productivity, environmental pollution losses and agricultural services in future scenarios. This article describes the methodology and the results of a study to evaluate the effect of climate change only on losses of nitrogen (N) and carbon (C) from grassland-based livestock systems in 10 UK Regional Development Programme (RDP) areas. In order to do so, a modelling framework integrating different models at the crop and farm level was developed and implemented. Simulated projections suggest that farming systems will undergo different changes in food production and associated nutrient losses depending on different areas and time-slices. Potential trade-offs on other pillars of farm sustainability (e.g. net farm income, biodiversity and soil quality) were simulated and illustrated as an example

Assessment of soil water, carbon and nitrogen cycling in reseeded grassland on the North Wyke Farm Platform using a process-based model

The North Wyke Farm Platform (NWFP) generates large volumes of temporally-indexed data that provides a valuable test-bed for agricultural mathematical models in temperate grasslands. In our study, we used the primary datasets generated from the NWFP (https://nwfp.rothamsted.ac.uk/) to validate the SPACSYS model in terms of the dynamics of water loss and forage dry matter yield estimated through cutting. The SPACSYS model is capable of simulating soil water, carbon (C) and nitrogen (N) balance in the soil-plant-atmosphere system. The validated model was then used to simulate the responses of soil water, C and N to reseeding grass cultivars with either high sugar (Lolium perenne L cv. AberMagic) or deep rooting (Festulotium cv. Prior) traits. Simulation results demonstrated that the SPACSYS model could predict reliably soil water, C and N cycling in reseeded grassland. Compared to AberMagic, the Nor grass could fix more C in the second year following reseeding, whereas less C was lost through soil respiration in the first transition year. In comparison to the grass cifitivar of the permanent pasture that existed before reseeding, both grasses reduced N losses through runoff and conhibuted to reducing water loss, especially Prior in relation to the latter. The SPACSYS model could predict these differences as supported by the rich dataset from the NWFP, providing a tool for future predictions on less characterized pasture. (C) 2017 The Authors. Published by Elsevier B.V. This is an open access articleRN the CC BY licens

A conceptual framework for understanding ecosystem trade-offs and synergies, in communal rangeland systems.

Communal rangelands are a global resource of significant benefit to society through the provision of critical ecosystem goods and services such as carbon sequestration, water and livestock forage. The relative importance of the ecosystem goods and services provided by communal rangelands is driven by the social and environmental priorities of a range of different stakeholders at the local, regional and national level. Understanding the potential ecosystem service trade-offs (and synergies) is vital for making informed and inclusive decisions as part of the process of stakeholder engagement, both in goal setting as well as evaluating the appropriateness of outcomes in rangelands. However, application of trade-offs approaches to communal rangelands, has frequently been limited by a lack of adequate stakeholder engagement to help define important factors such as the diverse objectives of end users and the broader institutional and policy environments that frame them. To help address this, we propose a framework that conceptualises the links between different actors and trade-offs at three key levels, using communal rangelands in South Africa as a case study. Firstly, we explore environment trade-offs between key ecosystem services, largely determined through public sector engagement in the formulation of environmental policy. Secondly, we examine the potential for environmental policies to create community-environment trade-offs between the needs of local communities and those of society more broadly. Thirdly, we consider community trade-offs reflecting the many different social and economic priorities of people living in communal systems. We suggest that the framework will find greatest application in the initial process of determining potential ecosystem service trade-offs and associated land use scenarios with key stakeholders, and then subsequently in connecting the trade-offs back to these stakeholders, following analysis, as part of a ‘discussion support’ process. We also discuss the broader applicability of this approach to rangelands systems outside of South Africa

A synthetic analysis of greenhouse gas emissions from manure amended agricultural soils in China

Application of manure has been recommended as an effective strategy to mitigate climate change. However, the magnitude of greenhouse gases emission derived by application of manure to agricultural soils across environmental conditions still remains unclear. Here, we synthesized data from 379 observations in China and quantified the responses of soil nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) emissions to manure (Org-M) in comparison to chemical fertilizers (Min-F) or non-fertilizers (Non-F). The results showed that N2O, CO2 and CH4 emissions were significantly affected by Org-M compared to Min-F (percentage change: −3, +15 and +60%, P <0.05) and Non-F (percentage change: +289, +84 and +83%, P<0.05), respectively. However, at the same amount of total N input, Org-M decreased soil N2O emission by 13% and CH4 emission by 12%, and increased soil CO2 emission by 26% relative to Min-F in upland soils. For paddy soils, N2O, CO2 and CH4 emissions differed by −3%, −36% and +84% between Org-M and Min-F (i.e., Org-M minus Min-F). Thus, practices such as application of manure instead of chemical fertilizer and decreasing nitrogen input rate need to be highly considered and optimized under different soils and climate conditions to mitigate GHGs emission in China

On correlation between canopy vegetation and growth indexes of maize varieties with different nitrogen efficiencies

Studying the canopy spectral reflection characteristics of different N-efficient maize varieties and analyzing the relationship between their growth indicators and spectral vegetation indices can help the breeding and application of N-efficient maize varieties. To achieve the optimal management of N fertilizer resources, developing N-efficient maize varieties is necessary. In this research, maize varieties, i.e., the low-N-efficient (Zhengdan 958, ZD958), the high-N efficient (Xianyu 335, XY335), the double-high varieties (Qiule 368, QL368), and the double inefficient-type varieties (Yudan 606 YD606), were used as materials. Results indicate that nitrogen fertilization significantly increased the vegetation indices NDVI, GNDVI, GOSAVI, and RVI of maize varieties with different nitrogen efficiencies. These findings were consistent with the performance of yield, dry matter mass, and leaf nitrogen content and were also found highest under both medium and high nitrogen conditions in the double-high variety QL368. The correlations of dry matter quality, leaf nitrogen content, yield, and vegetation indices (NDVI, GNDVI, RVI, and GOSAVI) at the filling stage of different N-efficient maize varieties were all highly significant and positive. In this relationship, the best effect was found at the filling stages, with correlation coefficients reaching 0.772–0.942, 0.774–0.970, 0754–0.960, and 0.800–0.960. The results showed that the yield, dry matter weight, and leaf nitrogen content of maize varieties with different nitrogen efficiencies increased first and then stabilized with the increase in the nitrogen application level in different periods, and the highest nitrogen application level of maize yield should be between 270 and 360 kg/hm2. At the filling stage, canopy vegetation index of maize varieties with different nitrogen efficiencies was positively correlated with yield, dry matter weight, and leaf nitrogen content, especially GNDVI and GOSAVI on the leaf nitrogen content. It can be used as a means to predict its growth index

Mineral N stock and nitrate accumulation in the 50 to 200 m profile on the Loess Plateau

Nitrogen (N) stored in deep profiles is important in assessing regional and/or global N stocks and nitrate leaching risk to groundwater. The Chinese Loess Plateau, which is characterized by significantly thick loess deposits, potentially stores immense stocks of mineral N, posing future threats to groundwater quality. In order to determine the vertical distributions of nitrate and ammonium content in the region, as well as to characterize the potential accumulation of nitrate in the deep loess profile, we study loess samples collected at five sites (Yangling, Changwu, Fuxian, An'sai and Shenmu) through a 50 to 200 m loess profile. The estimated storage of mineral N varied significantly among the five sites, ranging from 0.46 to 2.43 × 104 kg N ha−1. Ammonium exhibited fluctuations and dominated mineral N stocks within the whole profile at the sites, except for the upper 20–30 m at Yangling and Changwu. Measured nitrate content in the entire profile at Fuxian, An'sai and Shenmu is low, but significant accumulations were observed to 30–50 m depth at the other two sites. Analysis of δ15N and δ18O of nitrate indicates different causes for accumulated nitrate at these two sites. Mineralization and nitrification of manure and organic N respectively contribute nitrate to the 0–12 and 12–30 m profile at Changwu; while nitrification of NH4+ fertilizer, NO3− fertilizer and nitrification of organic N control the nitrate distribution in the 0–3, 3–7 and 7–10 m layer at Yangling, respectively. Furthermore, our analysis illustrates the low denitrification potential in the lower part of the vadose zone. The accumulated nitrate introduced by human activities is thus mainly distributed in the upper vadose zone (above 30 m), indicating, currently, a low nitrate leaching risk to groundwater due to a high storage capacity of the thick vadose zone in the region

Soil organic carbon storage impacts on crop yields in rice-based cropping systems under different long-term fertilisation

peer reviewedRice production in the Yangtze River Basin accounts for 44.4 % of China's total rice production. Exploring the response of crop yields to soil organic carbon (SOC) storage under various fertilisation treatments for maintaining high and sustainable crop yields is an urgent issue. A database containing information on crop yields, SOC content, environmental factors (climate and soil properties), and nutrient input from fertilisation was established from seven long-term experimental sites located in the middle and lower reaches of the Yangtze River Basin (operational since the 1980s/1990s) in two lowland rice-based cropping systems (i.e., rice–wheat rotation and rice–rice rotation systems). The study considered four treatments: no fertiliser application (CK); application of chemical nitrogen, phosphorus, and potassium fertilisers (NPK); application of manure (M); and a combination of NPK and M (NPKM). Results showed that the NPKM treatment produced the highest crop yields, followed by the NPK/M and CK treatments. The NPK and NPKM treatments generally had higher sustainable yield indices (SYI, 0.34–0.74) and lower coefficients of variation (CV, 11–32 %) than the M and CK treatments (SYI: 0.29–0.62 and CV: 15–44 %) in both cropping systems across all sites. Crop grain yields were significantly increased with increasing SOC storage (0–20 cm) and followed a logarithmic regression in both systems, suggesting that a further increase in SOC content could lead to higher yields. Structural equation modelling indicated that fertilisation, soil properties, and climate together explained 75–77 % of the variance in crop yield in the two systems. The primary contributing factors were fertilisation and its associated changes in soil nutrients. Chemical fertilisers mainly had direct effects on crop yields, while manure had both direct and indirect (through improvements in soil properties) effects on crop yields. In the rice–rice system, SOC alone had both direct and indirect (through the improved availability of soil nutrients) positive effects on crop yields. Our findings emphasise the potential benefits of sequestering SOC not only for enhancing crop production but also for improving the stability and sustainability of crop yield from paddy fields