Increased stocking rate and associated strategic dry-off decision rules reduced the amount of nitrate-N leached under grazing

peer-reviewedThe effect of intensive agricultural systems on the environment is of increasing global concern, and recent review articles have highlighted the need for sustainable intensification of food production. In grazing dairy systems, the leaching of nitrate-N (NO3-N) to groundwater is a primary environmental concern. A herd-level factor considered by many to be a key contributor to the amount of NO3-N leached from dairy pastures is stocking rate (SR), and some countries have imposed limits to reduce the risk of NO3-N loss to groundwater. The objective of the current experiment was to determine the effect of dairy cow SR on NO3-N leached in a grazing system that did not import feed from off-farm and had the same N fertilizer input. Five SR were evaluated (2.2, 2.7, 3.1, 3.7, and 4.3 cows/ha) in a completely randomized design (i.e., 2 replicates of each SR as independent farmlets) over 2 y. Pasture utilization, milk production/hectare, and days in milk/hectare increased with SR, but days in milk/cow and milk production/cow declined. The concentration of NO3-N in drainage water and the quantity of NO3-N leached/ha per year declined linearly with increasing SR, and the operating profit/kg NO3-N leached per ha increased. Higher SR was associated with fewer days in milk/cow, resulting in a reduction in estimated urine N excretion/cow (the main source of N leaching) during the climatically sensitive period for NO3-N leaching (i.e., late summer to winter). We hypothesized that the reduction in estimated urine N excretion per cow led to an increase in urinary N spread and reduced losses from urine patches. The results presented indicate that lowering SR may not reduce nitrate leaching and highlight the need for a full farm system-level analysis of any management change to determine its effect on productivity and environmental outcomes

Perceptions of trekking tourism and social and environmental change in Nepal's Himalayas

The Himalayas are among the world’s youngest mountain ranges. In addition to the geologic processes of mountain building and erosion, they are also highly vulnerable to human influenced change, occurring at local, national, regional, and international scales. A photo-elicitation methodology is employed to show how residents perceive those changes from historical perspectives, as well as their current conditions and impacts on their daily lives. Nepal’s Khumbu region has undergone major social and environmental transformations since the 1960s when international trekking first began to influence the area's economy. The current perceptions of Khumbu residents of these changes is assessed through photo-elicitation interviews. Their responses are placed in the historical context of: (i) institutional and political changes, much of which have been driven by national government policies; (ii) social and economic changes, for which the tourism economy has been central; and (iii) environmental changes, reflecting the impacts of resource management and climate change. The mostly positive perceptions of Khumbu residents toward how their region has changed reflects general improvements in the physical and cultural landscapes of the Khumbu over time, as well as its continuing geographic isolation, which has helped to slow the rate of globalization, while also keeping the region a dynamic and popular tourist destination

Identification Of Important Criteria In Farm Systems Decisions Around Lake Taupo

Nitrogen leaching from agriculture contributes to contamination of Lake Taupo. Multiple criteria decision making was used to compare fourteen pre-defined farming systems which reduced, or maintained nitrogen losses. Case study participants included three to four each of Maori Incorporation representatives, owner-operators, Environment Waikato employees, and researchers. The total group identified criteria that were important in choosing between the systems. Profit and nitrogen outputs were provided for the systems. Individuals weighted criteria and subjectively scored each system’s performance against the remaining criteria. Systems were ranked using this information. Variation within and between groups was considerable. Key criteria included: profit; farm sustainability; labour; enjoyment; risk (Maori); lifestyle and environmental sustainability (owner-operators)

How does co-product handling affect the carbon footprint of milk? Case study of milk production in New Zealand and Sweden

Purpose This paper investigates different methodologies of handling co-products in life cycle assessment (LCA) or carbon footprint (CF) studies. Co-product handling can have a significant effect on final LCA/CF results, and although there are guidelines on the preferred order for different methods for handling co-products, no agreed understanding on applicable methods is available. In the present study, the greenhouse gases (GHG) associated with the production of 1 kg of energy-corrected milk (ECM) at farm gate is investigated considering co-product handling. Materials and methods Two different milk production systems were used as case studies in the investigation of the effect of applying different methodologies in coproduct handling: (1) outdoor grazing system in New Zealand and (2) mainly indoor housing system with a pronounced share of concentrate feed in Sweden. Since the cows produce milk, meat (when slaughtered), calves, manure, hides, etc., the environmental burden (here GHG emissions) must be distributed between these outputs (in the present study no emissions are attributed to hides specifically, or to manure which is recycled on-farm). Different methodologically approaches, (1) system expansion (two cases), (2) physical causality allocation, (3) economic allocation, (4) protein allocation and (5) mass allocation, are applied in the study. Results and discussion The results show large differences in the final CF number depending on which methodology has been used for accounting co-products. Most evident is that system expansion gives a lower CF for milk than allocation methods. System expansion resulted in 63- 76% of GHG emissions attributed directly to milk, while allocation resulted in 85-98%. It is stressed that meat is an important by-product from milk production and that milk and beef production is closely interlinked and therefore needs to be considered in an integrated approach. Conclusions To obtain valid LCA/CF numbers for milk, it is crucial to account for by-products. Moreover, if CF numbers for milk need to be compared, the same allocation procedure should be applied. © 2011 Springer-Verlag

The interaction between milk and beef production and emissions from land use change - Critical considerations in life cycle assessment and carbon footprint studies of milk

Two most critical factors to address in environmental system analysis of future milk production are 1) the link between milk and beef production, and 2) the competition for land, possibly leading to land use change (LUC) with greenhouse gas (GHG) emissions and loss of biodiversity as important implications. Different methodological approaches concerning these factors, in studies on environmental impacts of dairy production, sometimes lead to contradictory results. Increasing milk yield per cow is often one of the solutions discussed in order to reduce GHG emissions from milk production. However, when also accounting for other systems affected (e.g. beef production) it is not certain that an increase in milk yield per cow leads to a reduction in total GHG emissions per kg milk. In the present study the correlation between carbon footprint (CF) of milk and the amount of milk delivered per cow is investigated for 23 dairy farms (both organic and conventional) in Sweden. Use of a fixed allocation factor of 90% (based on economic value) indicates a reduction in CF with increased milk yield, while no correlation can be noted when system expansion is applied. The average CF for two groups of farms, organic and high yielding conventional, is also calculated. When conducting system expansion the CF is somewhat lower for the organic farms (which have a lower milk yield per cow, but more meat per kg milk), but when a 90% allocation factor is used, the CF is somewhat higher for the organic farms compared to the high yielding conventional farms. In analysis of future strategies for milk production, it is suggested that system expansion should be applied, in order to also account for environmental impacts from affected systems. Thus, scenarios for milk and meat production should be analysed in an integrated approach in order to reduce total emissions from the livestock sector. How to account for emissions from LUC is highly debated and there is no current shared consensus. Different LUC methods result in significantly different results. In this study, four different LUC methods are applied, using data for organic milk production and high yielding conventional milk production systems in Sweden. Depending on which LUC method was applied, the organic system showed about 50% higher or 40% lower CF compared to the conventional high yielding system. Thus, when reporting CF numbers, it is important to report LUC-factors separately and clearly explain the underlying assumptions, since the method of accounting for LUC can drastically change the results. \ua9 2011 Elsevier Ltd. All rights reserved

The impact of various parameters on the carbon footprint of milk production in New Zealand and Sweden

The carbon footprint (CF) of milk production was analysed at the farm gate for two contrasting production systems; an outdoor pasture grazing system in New Zealand (NZ) and a mainly indoor housing system with pronounced use of concentrate feed in Sweden (SE). The method used is based on the conceptual framework of lifecycle assessment (LCA), but only for greenhouse gas (GHG) emissions. National average data were used to model the dairy system in each country. Collection of inventory data and calculations of emissions were harmonised to the greatest extent possible for the two systems. The calculated CF for 1kg of energy corrected milk (ECM), including related by-products (surplus calves and culled cows), was 1.00kg carbon dioxide equivalents (CO2e) for NZ and 1.16kg CO2e for SE. Methane from enteric fermentation and nitrous oxide emissions from application of nitrogen (as fertiliser and as excreta dropped directly on the field) were the main contributors to the CF in both countries. The most important parameters to consider when calculating the GHG emissions were dry matter intake (DMI), emission factor (EF) for methane from enteric fermentation, amount of nitrogen applied and EF for direct nitrous oxide emissions from soils. By changing one parameter at a time within 'reasonable' limits (i.e. no extreme values assumed), the impact on the total CF was assessed and showed changes of up to 15%. In addition, the uncertainty in CF estimates due to uncertainty in EF for methane from enteric fermentation and nitrous oxide emissions (from soil and due to ammonia volatilisation) were analysed through Monte Carlo simulation. This resulted in an uncertainty distribution corresponding to 0.60-1.52kg CO2e kg-1 ECM for NZ and 0.83-1.56kg CO2e kg-1 ECM for SE (in the prediction interval 2.5-97.5%). Hence, the variation within the systems based on the main EF is relatively large compared with the difference in CF between the countries. © 2011 Elsevier Ltd

Increased stocking rate and associated strategic dry-off decision rules reduced the amount of nitrate-N leached under grazing

peer-reviewedThe effect of intensive agricultural systems on the environment is of increasing global concern, and recent review articles have highlighted the need for sustainable intensification of food production. In grazing dairy systems, the leaching of nitrate-N (NO3-N) to groundwater is a primary environmental concern. A herd-level factor considered by many to be a key contributor to the amount of NO3-N leached from dairy pastures is stocking rate (SR), and some countries have imposed limits to reduce the risk of NO3-N loss to groundwater. The objective of the current experiment was to determine the effect of dairy cow SR on NO3-N leached in a grazing system that did not import feed from off-farm and had the same N fertilizer input. Five SR were evaluated (2.2, 2.7, 3.1, 3.7, and 4.3 cows/ha) in a completely randomized design (i.e., 2 replicates of each SR as independent farmlets) over 2 y. Pasture utilization, milk production/hectare, and days in milk/hectare increased with SR, but days in milk/cow and milk production/cow declined. The concentration of NO3-N in drainage water and the quantity of NO3-N leached/ha per year declined linearly with increasing SR, and the operating profit/kg NO3-N leached per ha increased. Higher SR was associated with fewer days in milk/cow, resulting in a reduction in estimated urine N excretion/cow (the main source of N leaching) during the climatically sensitive period for NO3-N leaching (i.e., late summer to winter). We hypothesized that the reduction in estimated urine N excretion per cow led to an increase in urinary N spread and reduced losses from urine patches. The results presented indicate that lowering SR may not reduce nitrate leaching and highlight the need for a full farm system-level analysis of any management change to determine its effect on productivity and environmental outcomes