Estelle J. Dominati

Nitrogen Cycling from Increased Soil Organic Carbon Contributes Both Positively and Negatively to Ecosystem Services in Wheat Agro-Ecosystems

Soil organic carbon (SOC) is an important and manageable property of soils that impacts on multiple ecosystem services through its effect on soil processes such as nitrogen (N) cycling and soil physical properties. There is considerable interest in increasing SOC concentration in agro-ecosystems worldwide. In some agro-ecosystems, increased SOC has been found to enhance the provision of ecosystem services such as the provision of food. However, increased SOC may increase the environmental footprint of some agro-ecosystems, for example by increasing nitrous oxide emissions. Given this uncertainty, progress is needed in quantifying the impact of increased SOC concentration on agro-ecosystems. Increased SOC concentration affects both N cycling and soil physical properties (i.e., water holding capacity). Thus, the aim of this study was to quantify the contribution, both positive and negative, of increased SOC concentration on ecosystem services provided by wheat agro-ecosystems. We used the Agricultural Production Systems sIMulator (APSIM) to represent the effect of increased SOC concentration on N cycling and soil physical properties, and used model outputs as proxies for multiple ecosystem services from wheat production agro-ecosystems at seven locations around the world. Under increased SOC, we found that N cycling had a larger effect on a range of ecosystem services (food provision, filtering of N, and nitrous oxide regulation) than soil physical properties. We predicted that food provision in these agro-ecosystems could be significantly increased by increased SOC concentration when N supply is limiting. Conversely, we predicted no significant benefit to food production from increasing SOC when soil N supply (from fertiliser and soil N stocks) is not limiting. The effect of increasing SOC on N cycling also led to significantly higher nitrous oxide emissions, although the relative increase was small. We also found that N losses via deep drainage were minimally affected by increased SOC in the dryland agro-ecosystems studied, but increased in the irrigated agro-ecosystem. Therefore, we show that under increased SOC concentration, N cycling contributes both positively and negatively to ecosystem services depending on supply, while the effects on soil physical properties are negligible.

Pedometric Valuation of the Soil Resource

Soil forms the thin skin of the Earth and is the site of many ecological processes, transformations, and fluxes. It forms the substrate for most of the activities that take place at the Earth’s surface, including almost all food production and human occupation, and underpins both natural and managed ecosystems. Soils differ in their structure, composition, and ability to function under a use. Soil is a multifunctional resource that affects human well-being both directly (e.g., food provision) and indirectly (e.g., surface and groundwater supplies) and that affects all near-land surface ecological processes. Clearly, soil is “valuable” as that term is understood in common language. The pedometric program as outlined in this book, i.e., the development of “quantitative methods for the study of soil distribution … as a sustainable resource,” should therefore include an attempt to quantify this value. Chapter 1 of the present book lists as the third of four items on the pedometric agenda “evaluating the utility and quality of soil,” and it is in this sense that we attempt in this chapter to define and quantify the value of the soil resource. This process is referred to as “valuation.”

Looking to the future of land evaluation at farm scale

ABSTRACT Land evaluation has a long history of describing and quantifying the sustainable productive capacity of land, but there is a global recognition of the need for this discipline to evolve and recognise other services, beyond food production, provided by landscapes which contribute to human well-being, as well as account for impacts on receiving environments. In this paper, we explore if a natural capital ecosystem service approach could be added to the land evaluation and farm planning process to enable the quantification and valuation of all benefits obtained from farm landscapes. Bringing (i) ecological theory (that provides the relationship between stocks and processes and supports the premise that the manipulation of key stock attributes changes ecosystem function and service provision) together with (ii) land evaluation (a process embedded in geology, geomorphology and soil science, which in actual practice puts heavy emphasis on an agro-technical analysis) and (iii) farm planning (which has more of a focus on socio-economic constraints to the production system) enables more of the interactions between the intensity of a use and practice and the natural and built capital stocks, as they influence the provision of all services to be examined. Furthermore, the analysis of the farm businesses can be extended beyond production and associated financial analysis only, to an integrated analysis that includes other services. The proposed approach addresses a number of the limitations of the current approach to land evaluation and farm planning.

Change in ecosystem service provision within a lowland dairy landscape under different riparian margin scenarios

ABSTRACT Riparian margins can provide a range of environmental, social, and production benefits both on-farm and off-farm. However, our understanding of the relative advantage between various riparian-margin management options is limited. We aim to advance this knowledge by modelling change in food provision, water quality regulation, contact recreation, and amenity ecosystem services in response to riparian-margin management. Estimations in performance were made under grazed; fenced 1 m-wide grass-strips; and fenced 5 m-wide multi-tier planted riparian margin scenarios within a lowland dairy farming landscape as typical in the North Island, New Zealand. Our study allows for simultaneous analysis across the range of ecosystem services (provisioning, regulating, and cultural) and across spatial scales (farm, river network, catchment) as relevant to current policy focus for riparian management. We show both grass-strips and multi-tier planted margins can maintain or increase production values, while also making important contributions to environmental stewardship and community values. Under a multi-tier planted margin scenario, provision of amenity values also increases. Importantly, we also show that riparian management alone is not adequate to address detrimental outcomes of land use on receiving environments, and should be part of wider farm management practices used to maximise opportunities for sustained ecosystem service provision. This is an important consideration for land management policies.

Understanding Soils’ Contribution to Ecosystem Services Provision to Inform Farm System Analysis

Amongst our natural resources, soils are often forgotten and poorly represented in resource management decision-making processes. Increasing global concerns about soil degradation combined with the ever-growing demands for the finite land resource demonstrate that the time is rapidly arriving when land evaluation needs to include consideration of all the ecosystem services provided to humans by a combination of land type, climate, land use and management practices. The feasibility of using an ecosystems approach to address this gap in land evaluation procedure and provide better soil security is explored here.