title: Phosphorus Distribution In Relation To Soil Landscape Groups In Steep North Island Hill Country In New Zealand

authors: Arrowsmith, Max

subjects: Phosphorus

abstract: Phosphorus fertiliser is necessary to maintain the production of New Zealand hill country pastures. Technological advances in GIS and GPS have given aerial fertiliser applicators more precision than ever before.  The key question is; to what extent do soil chemical properties vary within hill country landscapes, and is a knowledge of the variability able to be used to differentially apply fertiliser, maximise P fertiliser use efficiency, and minimise P loss to waterways? The objective of this thesis was to quantify the phosphorus variability on Blue Duck Station, a summer-moist hill-country farm located in the Central North Island of New Zealand. The soil comprised Allophanic Soil (Andisols) on the flat to low slopes with Brown Soil (Inceptisols) on the steeper hills.
Blue Duck Station was delineated into six soil-landscape groups (north facing medium slopes, north facing steep slopes, south facing steep slopes, south facing medium slopes, flat ridge tops, and flat valley floors, based on slope, aspect, and elevation using GIS. Three replicate units were randomly selected from each of the six soil-landscape groups, which gave 18 study-sites in total. For each study site, one transect sample and five grid samples were collected. Olsen P, Anion Storage Capacity, pH, Sulphate-sulphur and Cations (Mg, Na, K, Ca) were determined.
The Olsen P ranged from a mean of 6.8 in the south facing medium slopes to 21.2 in the north facing medium slopes. North facing medium slopes and valley low floors had higher mean Olsen P values than all other landscape groups (P<0.01) and also had the greatest variability in Olsen P values. The majority of Olsen P values were considered ‘low’ or ‘very low’. Soil pH was consistent, ranging between 5 and 5.4, whilst anion storage capacity (ASC) levels ranged from 35% to 85%. High ASC levels indicated soils of volcanic origin, containing tephra, whereas low ASC levels were associated with soil predominantly derived from tertiary sedimentary rock.
At Blue Duck Station, the application of higher rates of P fertiliser to south facing steep slopes and south facing medium slopes, with medium rates of P fertiliser addition to north facing steep slopes and ridge low slopes would optimise fertiliser use. There is limited benefit in applying fertiliser to north medium slopes and flat valley floors as Olsen P is near optimal for this environment and stock transfer will continue to add nutrients to these areas.
The variability within a sample site (between grid and transect samples) was often greater than the range of variability the means across all the landscape groups. Due to such large sample variability, difficulties arise when attempting to recommend accurate fertiliser regime, or sampling programs. The soil analysis results from a small number of samples should be treated with caution.  
The Best Management Practice for soil sampling the Central North Island Hill Country would be to avoid sampling small exceptional areas like flat valley floors and flat ridge tops. Focusing sample regimes on a number of transects across northern and southern slopes would give more representative results.

text: Phosphorus Distribution In Relation To Soil Landscape Groups In Steep North Island Hill Country In New Zealand Phosphorus fertiliser is necessary to maintain the production of New Zealand hill country pastures. Technological advances in GIS and GPS have given aerial fertiliser applicators more precision than ever before.  The key question is; to what extent do soil chemical properties vary within hill country landscapes, and is a knowledge of the variability able to be used to differentially apply fertiliser, maximise P fertiliser use efficiency, and minimise P loss to waterways? The objective of this thesis was to quantify the phosphorus variability on Blue Duck Station, a summer-moist hill-country farm located in the Central North Island of New Zealand. The soil comprised Allophanic Soil (Andisols) on the flat to low slopes with Brown Soil (Inceptisols) on the steeper hills.
Blue Duck Station was delineated into six soil-landscape groups (north facing medium slopes, north facing steep slopes, south facing steep slopes, south facing medium slopes, flat ridge tops, and flat valley floors, based on slope, aspect, and elevation using GIS. Three replicate units were randomly selected from each of the six soil-landscape groups, which gave 18 study-sites in total. For each study site, one transect sample and five grid samples were collected. Olsen P, Anion Storage Capacity, pH, Sulphate-sulphur and Cations (Mg, Na, K, Ca) were determined.
The Olsen P ranged from a mean of 6.8 in the south facing medium slopes to 21.2 in the north facing medium slopes. North facing medium slopes and valley low floors had higher mean Olsen P values than all other landscape groups (P<0.01) and also had the greatest variability in Olsen P values. The majority of Olsen P values were considered ‘low’ or ‘very low’. Soil pH was consistent, ranging between 5 and 5.4, whilst anion storage capacity (ASC) levels ranged from 35% to 85%. High ASC levels indicated soils of volcanic origin, containing tephra, whereas low ASC levels were associated with soil predominantly derived from tertiary sedimentary rock.
At Blue Duck Station, the application of higher rates of P fertiliser to south facing steep slopes and south facing medium slopes, with medium rates of P fertiliser addition to north facing steep slopes and ridge low slopes would optimise fertiliser use. There is limited benefit in applying fertiliser to north medium slopes and flat valley floors as Olsen P is near optimal for this environment and stock transfer will continue to add nutrients to these areas.
The variability within a sample site (between grid and transect samples) was often greater than the range of variability the means across all the landscape groups. Due to such large sample variability, difficulties arise when attempting to recommend accurate fertiliser regime, or sampling programs. The soil analysis results from a small number of samples should be treated with caution.  
The Best Management Practice for soil sampling the Central North Island Hill Country would be to avoid sampling small exceptional areas like flat valley floors and flat ridge tops. Focusing sample regimes on a number of transects across northern and southern slopes would give more representative results.

year: 2013

title: Pilot-scale continuous pyrolysis of Pinus Radiatta sawdust

authors: Sichone, Kavwa

abstract: Lakeland Steel Limited developed a pilot plant for pyrolysing sawdust which proved successful in recent trials with sawdust and organic waste processing. Lakeland Steel was approached by a client to perform a preliminary economic assessment of a mobile sawdust pyrolysis unit. Feedstock properties such as proximate composition, elemental composition, calorific content, thermal decomposition reaction kinetics, and drying properties were determined. Pilot plant trials investigated the effects of processing parameters on product yields and properties. The parameters were feedstock moisture content at 15, 30 and 60%, reaction temperature at 400, 450 and 500°C and reactor auger speeds at 15, 20 and 25 rpm. Experiments at 60% moisture could not be performed to completion as the auger blocked repeatedly. The other two moisture contents showed that moisture content enhanced heat exchange properties of the feedstock and this generally increased the amount of volatile organic matter released. It was observed that for 15% moisture sawdust increase of temperature did not consistently exhibit an increase in degree of devolatilisation of organic matter. However, the 30% moisture sawdust showed an increase in devolatilisation with increase in temperature. The effects of increasing reactor auger speed had the most consistent trend with which an increase in speed showed a decrease in degree of devolatilisation thus increasing char yield.
A preliminary economic feasibility assessment was performed for the base case scenario which processed 29,000 tonnes/per year of green sawdust pre-dried to 15% moisture content at 400°C. The facility produced 5,250 tons biochar, 2,140 tons oil and 6,290 tons syngas per year. The syngas was recycled for heating and excess heat was also recovered from product cooling operations. However an additional 170 kg/hr. of natural gas was required to produce the required processing temperatures during start-up. The base case assessment was uneconomic, operating costs, including labour, were $1,200,000 per year and sales were $780,000 per year, assuming biochar could be sold for $150 per tonne. A sensitivity analysis showed that the process economics could be favourable assuming lower capital costs by eliminating the need for a rotary dryer and 50% reduction of labour costs by process automation. Provided that the char is sold at $150 per ton a payback period of four years can be achieved.

text: Pilot-scale continuous pyrolysis of Pinus Radiatta sawdust Lakeland Steel Limited developed a pilot plant for pyrolysing sawdust which proved successful in recent trials with sawdust and organic waste processing. Lakeland Steel was approached by a client to perform a preliminary economic assessment of a mobile sawdust pyrolysis unit. Feedstock properties such as proximate composition, elemental composition, calorific content, thermal decomposition reaction kinetics, and drying properties were determined. Pilot plant trials investigated the effects of processing parameters on product yields and properties. The parameters were feedstock moisture content at 15, 30 and 60%, reaction temperature at 400, 450 and 500°C and reactor auger speeds at 15, 20 and 25 rpm. Experiments at 60% moisture could not be performed to completion as the auger blocked repeatedly. The other two moisture contents showed that moisture content enhanced heat exchange properties of the feedstock and this generally increased the amount of volatile organic matter released. It was observed that for 15% moisture sawdust increase of temperature did not consistently exhibit an increase in degree of devolatilisation of organic matter. However, the 30% moisture sawdust showed an increase in devolatilisation with increase in temperature. The effects of increasing reactor auger speed had the most consistent trend with which an increase in speed showed a decrease in degree of devolatilisation thus increasing char yield.
A preliminary economic feasibility assessment was performed for the base case scenario which processed 29,000 tonnes/per year of green sawdust pre-dried to 15% moisture content at 400°C. The facility produced 5,250 tons biochar, 2,140 tons oil and 6,290 tons syngas per year. The syngas was recycled for heating and excess heat was also recovered from product cooling operations. However an additional 170 kg/hr. of natural gas was required to produce the required processing temperatures during start-up. The base case assessment was uneconomic, operating costs, including labour, were $1,200,000 per year and sales were $780,000 per year, assuming biochar could be sold for $150 per tonne. A sensitivity analysis showed that the process economics could be favourable assuming lower capital costs by eliminating the need for a rotary dryer and 50% reduction of labour costs by process automation. Provided that the char is sold at $150 per ton a payback period of four years can be achieved.

year: 2013

title: Cultural justice, ethics and teaching

authors: Nairn, Ray

subjects: Maori

abstract: Te Tiriti o Waitangi provides both a basis for cultural justice in this society and an explication of the term; each of the articles identifying a significant aspect of cultural justice. First, there is the guarantee to the Maori signatories that the Crown would protect their independence - tino rangatiratanga, (also read as authority, autonomy or self-determination) [Article II]. In Article III Maori are promised that they will also have the “Rights and Privileges of British subjects”. Finally, in Article I, Maori cede to the Crown the right to govern, to make laws to protect all peoples from the evil consequences of lawlessness. The 1835 Declaration of Independence located legislative authority in the Wakaminenga (the gathered rangatira meeting in Congress); and in 1840, in the context of the Crown promises, Maori authorised the Crown to exercise that authority. For Maori Te Tiriti specifies cultural justice for interactions between Maori and settlers in the new society. Maori are guaranteed the right to self-determination (and the economic and social resources to make that practical) in their relations with New Zealand society. They are also entitled to the same opportunities as other citizens. The latter rights, embodied in local legislation and international covenants to which we are signatory, are not alternatives to the prior right of Maori people to their (cultural) autonomy. The exercise of legislative and organisational authority must be exercised in a manner consistent with the promises which clearly requires consultation and negotiation with Maori.

text: Cultural justice, ethics and teaching Te Tiriti o Waitangi provides both a basis for cultural justice in this society and an explication of the term; each of the articles identifying a significant aspect of cultural justice. First, there is the guarantee to the Maori signatories that the Crown would protect their independence - tino rangatiratanga, (also read as authority, autonomy or self-determination) [Article II]. In Article III Maori are promised that they will also have the “Rights and Privileges of British subjects”. Finally, in Article I, Maori cede to the Crown the right to govern, to make laws to protect all peoples from the evil consequences of lawlessness. The 1835 Declaration of Independence located legislative authority in the Wakaminenga (the gathered rangatira meeting in Congress); and in 1840, in the context of the Crown promises, Maori authorised the Crown to exercise that authority. For Maori Te Tiriti specifies cultural justice for interactions between Maori and settlers in the new society. Maori are guaranteed the right to self-determination (and the economic and social resources to make that practical) in their relations with New Zealand society. They are also entitled to the same opportunities as other citizens. The latter rights, embodied in local legislation and international covenants to which we are signatory, are not alternatives to the prior right of Maori people to their (cultural) autonomy. The exercise of legislative and organisational authority must be exercised in a manner consistent with the promises which clearly requires consultation and negotiation with Maori.

year: 1993