A farm level approach to define successful mitigation strategies for GHG emissions from ruminant livestock systems

Abstract

Ruminant livestock systems are a significant source of greenhouse gases (GHGs). Thus far, mitigation options for GHG emissions mainly focused on a single gas, and are treated as isolated activities. The present paper proposes a framework for a farm level approach for the full accounting of GHG emissions. The methodology accounts for the relevant direct and indirect emissions of methane, nitrous oxide and carbon dioxide, including carbon sequestration. Furthermore, the potential trade-off with ammonia volatilisation and nitrate leaching are taken into account. A ruminant livestock farm is represented with a conceptual model consisting of five pools: animal, manure, soil, crop and feed. The carbon and nitrogen inputs, throughputs and outputs are described, and the direct emissions are related to the carbon and nitrogen flows. The indirect emissions included in the methodology are mainly carbon dioxide emissions from energy use and nitrous oxide emissions related to imported resources and nitrogen losses. The whole farm approach is illustrated with a case of two dairy farms with contrasting livestock density and grassland management. It is shown that the inclusion of carbon sequestration and all indirect emissions have a major impact on the GHG budget of the farm. For one farm, the effect of four mitigation options on the GHG emissions was quantified. It was concluded that a whole farm approach of full accounting contributes to a better insight in the interactions between the carbon and nitrogen flows and the resulting emissions, within and outside the farm boundaries. Consequently, the methodology can be used to develop efficient and effective mitigation strategies.

Influence of increasing temperature and nitrogen input on greenhouse gas emissions from a desert steppe soil in Inner Mongolia

“…World-wide grassland occupies about 24% of the land area and contributes to 17% of total agricultural GHG emissions (Schils et al 2005). In China, grasslands occupy about 400 million ha.…”

Energy consumption in mixed crop-sheep farming systems: what factors of variation and how to decrease?

“…This work, which was based on both field observations and on simulations at farming system level (Schils et al, 2005;Matthews et al, 2006), aimed to highlight the main factors of EEf. It is essential to distinguish EEf and at sheep unit level (EEs), as the efficiency of cash crop unit (EEcc) is much higher than EEs and is a major contributor to EEf (Bochu, 2007).…”

Predicting the profile of nutrients available for absorption: from nutrient requirement to animal response and environmental impact

“…However, the drawbacks of current empirical energy and protein systems described in the previous sections also limit prediction of animal response and subsequently excretion of unused nutrients. Another example is the whole-farm model with five subsystems (animal, feed, manure, soil, crop) of Schils et al (2005) to estimate methane emissions. In the animal submodel, methane production is a linear function of milk production assuming a fixed conversion factor of 0.01 kg methane produced per cow per year per kg milk.…”