Multiple small monthly doses of dicyandiamide (DCD) did not reduce denitrification in Waikato dairy pasture

The effectiveness of multiple small doses of the nitrification inhibitor dicyandiamide (DCD) to decrease denitrification under warm moist conditions was tested in a 1-year field trial on a grazed dairy pasture. DCD was applied approximately every 4 weeks as an aqueous spray onto ten replicate plots 3 days after rotational grazing by dairy cows. Each application was at the rate of 3 kg DCD ha⁻¹, with a total annual application of 33 kg ha⁻¹. Denitrification was assessed 5 days after each DCD application using the acetylene block method. At the end of the trial, the rate of degradation of DCD under summer conditions was measured. DCD significantly decreased the mean annual nitrate concentration by about 17%. Denitrification and denitrification enzyme activity were highly variable and no significant effect of DCD in decreasing denitrification was detected. In the summer month of December, DCD degraded rapidly with an estimated half-life of 5 ± 3 days (mean and standard deviation)

Regional Economic Implications of Water Allocation and Reliability

The understanding of how allocation decisions can maximise the economic returns to the community from water for irrigation has received little attention, but is a significant issue for regional councils, those interested in water allocation policy development, and for irrigated farmers. There is a tradeoff between the amount of irrigated area and the reliability with which it can be undertaken. Overseas studies have generated a curve with optimum levels of allocation which maximise the economic return to the community from the resource. The study on which this paper is based used a single case study to model the individual and regional economic outcomes for four scenarios of water allocation, using daily time step simulation models of the hydrological, irrigation, farm and financial systems over the 1973 – 2000 period. The results show that there is an increasing return to the region as the allocation from the resource increases, at the expense of lower returns to existing users.Irrigation, reliability, regional economic impacts, Agribusiness, Agricultural and Food Policy, Agricultural Finance, Community/Rural/Urban Development, Environmental Economics and Policy, Farm Management, Financial Economics, Institutional and Behavioral Economics, Land Economics/Use, Resource /Energy Economics and Policy,

The Potential Cost to New Zealand Dairy Farmers from the Introduction of Nitrate-Based Stocking Rate Restrictions

Introducing a stocking rate restriction is one possible course of action for regulators to improve water quality where it is affected by nitrate pollution. To determine the impact of a stocking rate restriction on a range of New Zealand dairy farms, a whole-farm model was optimised with and without a maximum stocking rate of 2.5 cows per hectare. Three farm systems, which differ by their level of feed-related capital, were examined for the changes to the optimal stocking rate and optimal level of animal milk production genetics when utility was maximised. The whole-farm model was optimised through the use of an evolutionary algorithm called differential evolution. The introduction of a stocking rate restriction would have a very large impact on the optimally organised high feed-related capital farm systems, reducing their certainty equivalent by almost half. However, there was no impact on the certainty equivalent of low feed-related capital systems.environmental regulation, dairy farms, whole-farm model, evolutionary algorithm, Environmental Economics and Policy, Livestock Production/Industries, Q12, Q52, C61,

Global Spatial Risk Assessment of Sharks Under the Footprint of Fisheries

Effective ocean management and conservation of highly migratory species depends on resolving overlap between animal movements and distributions and fishing effort. Yet, this information is lacking at a global scale. Here we show, using a big-data approach combining satellite-tracked movements of pelagic sharks and global fishing fleets, that 24% of the mean monthly space used by sharks falls under the footprint of pelagic longline fisheries. Space use hotspots of commercially valuable sharks and of internationally protected species had the highest overlap with longlines (up to 76% and 64%, respectively) and were also associated with significant increases in fishing effort. We conclude that pelagic sharks have limited spatial refuge from current levels of high-seas fishing effort. Results demonstrate an urgent need for conservation and management measures at high-seas shark hotspots and highlight the potential of simultaneous satellite surveillance of megafauna and fishers as a tool for near-real time, dynamic management

Factors Effecting the Implementation by Landowners of Riparian Management Policies

The results of this project are intended to assist social agencies using educational or economic incentives, to promote voluntary adoption by farmers of riparian management policies. Farmers attending workshops in Taranaki in April 1998 were surveyed to identify the criteria they used to select their preferred riparian policies and reject others. Farmer use of decision criteria was analysed using the Analytical Hierarchy Process and its results compared with their likelihood of using the policies. The riparian management policies included in the study were: permanently excluding livestock, planting timber trees, planting conservation trees, excluding fertilisers, excluding chemicals, or doing nothing distinctive. The farmers most preferred the planting of conservation trees in riparian areas to the other policies. Their policy preferences were highly correlated (r = 0.76-0.96) with policy benefits, but appeared unrelated to the results of the cost benefit analysis. Further research is needed into farmer decision making on their riparian management before a decision model can be developed that satisfactorily explains farmer behaviour

Regional Economic Implications of Water Allocation and Reliability

The understanding of how allocation decisions can maximise the economic returns to the community from water for irrigation has received little attention, but is a significant issue for regional councils, those interested in water allocation policy development, and for irrigated farmers. There is a tradeoff between the amount of irrigated area and the reliability with which it can be undertaken. Overseas studies have generated a curve with optimum levels of allocation which maximise the economic return to the community from the resource. The study on which this paper is based used a single case study to model the individual and regional economic outcomes for four scenarios of water allocation, using daily time step simulation models of the hydrological, irrigation, farm and financial systems over the 1973 – 2000 period. The results show that there is an increasing return to the region as the allocation from the resource increases, at the expense of lower returns to existing users

Land-water interactions in five contrasting dairying catchments: issues and solutions

Monitoring of five dairy farming catchment streams in New Zealand shows they have high concentrations of N and P forms and faecal indicator bacteria. Suspended solids (SS) concentrations are sometimes high because of poor riparian management. Trend analysis and specific yields of N, P and SS for two streams that have been monitored for five years indicates that little change has occurred in water quality. However, improved water quality has been detected in the trends for two streams that have been monitored for 10 years, as a result of reductions in point sources and improved stock management (less intensive grazing and better stream bank fencing) that have taken place over the longer period. Surveys of farm management practices have been conducted at two-yearly intervals and best management practices are recommended for farming in each catchment, based on identified linkages between land use and water quality

The Potential Cost to New Zealand Dairy Farmers from the Introduction of Nitrate-Based Stocking Rate Restrictions

Introducing a stocking rate restriction is one possible course of action for regulators to improve water quality where it is affected by nitrate pollution. To determine the impact of a stocking rate restriction on a range of New Zealand dairy farms, a whole-farm model was optimised with and without a maximum stocking rate of 2.5 cows per hectare. Three farm systems, which differ by their level of feed-related capital, were examined for the changes to the optimal stocking rate and optimal level of animal milk production genetics when utility was maximised. The whole-farm model was optimised through the use of an evolutionary algorithm called differential evolution. The introduction of a stocking rate restriction would have a very large impact on the optimally organised high feed-related capital farm systems, reducing their certainty equivalent by almost half. However, there was no impact on the certainty equivalent of low feed-related capital systems

Land-water interactions in five contrasting dairying catchments: issues and solutions

Monitoring of five dairy farming catchment streams in New Zealand shows they have high concentrations of N and P forms and faecal indicator bacteria. Suspended solids (SS) concentrations are sometimes high because of poor riparian management. Trend analysis and specific yields of N, P and SS for two streams that have been monitored for five years indicates that little change has occurred in water quality. However, improved water quality has been detected in the trends for two streams that have been monitored for 10 years, as a result of reductions in point sources and improved stock management (less intensive grazing and better stream bank fencing) that have taken place over the longer period. Surveys of farm management practices have been conducted at two-yearly intervals and best management practices are recommended for farming in each catchment, based on identified linkages between land use and water quality.Resource /Energy Economics and Policy,