R. L. Parfitt

• PhD
• Retired at Manaaki Whenua - Landcare Research

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The literature on the formation, structure and properties of allophane and imogolite is reviewed, with particular emphasis on the seminal contributions by Colin Farmer. Allophane and imogolite occur not only in volcanic-ash soils but also in other environments. The conditions required for the precipitation of allophane and imogolite are discussed....

Infrared spectroscopic techniques have been used to obtain a structural model for the surface reaction between iron oxides and phosphate ions. Two surface hydroxyl ions (or water molecules) are replaced by one phosphate ion. Two of the oxygen atoms of the phosphate ion are coordinated, each to a different Fe ³⁺ ion, resulting in a binuclear surface...

The organic matter in density and particle size fractions of an Andisol and an Inceptisol has been characterised by its C and N contents and infrared spectra. The soils have a similar texture but different clay mineralogy and are under two contrasting land uses represented by pasture and cropping. The Andisol samples were taken from sites which hav...

Adsorption isotherms were obtained for fulvic and humic acids on synthetic gibbsite and goethite and on a natural imogolite. The results were interpreted with the help of spectra of the adsorption complexes, and measurements of hydroxyl displaced. The mechanism of adsorption involved ligand exchange with the surface hydroxyl groups and hydrogen bon...

Long-term (c. 40 years) tree population and soil data from conifer/angiosperm forests that have developed since the last major volcanic eruption (ad 232) in the central North Island of New Zealand were used to test the hypothesis that the shift from conifer to angiosperm dominance away from the eruption centre represents a chronosequence. The propo...

Farms of different N status under grazed pasture were used to assess Galloway's model of N saturation in a soil in New Zealand

The fate of sodium monofluoroacetate (1080) in soil and water was measured using experiments with water in the lab and experiments in the field with soils and stream waters.

Future human well-being under climate change depends on the ongoing delivery of food, fibre and wood from the land-based primary sector. The ability to deliver these provisioning services depends on soil-based ecosystem services (e.g. carbon, nutrient and water cycling and storage), yet we lack an in-depth understanding of the likely response of so...

Valuing natural capital: New Zealand trades on its natural capital stocks. At the heart of these stocks are our soils. With the area of elite and versatile soils (i.e. LUC classes 1 and 2) limited to 1.4 million ha, most pastoral agriculture is practiced on less versatile soils. These include soils derived from loess, alluvium or coastal sands, all...

Bibliography to accompany the report 'Nutrient Management Science - state of knowledge'

We examined changes in soil pH and total carbon (C), nitrogen (N) and bicarbonate phosphorus (bicarbonate-P) in resampled sites under grazed pastures, using two data sets on commercial farms. These were a soil quality (SQ) data set (0–10 cm soil depth; samples collected along transects) and a soil profile data set from National Soils Database (NSD)...

The capacity of a soil to sequester organic carbon can, in theory, be estimated as the difference between the existing soil organic C (SOC) concentration and the SOC saturation value. The C saturation concept assumes that each soil has a maximum SOC storage capacity, which is primarily determined by the characteristics of the fine mineral fraction...

Careful temporal measurements of soil C and N stocks in pasture-based agriculture are needed to quantify effects of different grazing management practices on stocks for a wide range of soils. In a previous New Zealand study, 83 soil profiles were re-sampled two to four decades after an initial sampling. Soil C and N stocks were compared to that det...

The Ministry for Primary Industries commissioned scientists from the Soil and Land Use Alliance (AgResearch, Landcare Research, Plant and Food Research, and Scion) to review research on nutrient management science for the primary sector between 1998 and 2013. The aim was to identify the current state of scientific knowledge, the use and uptake of t...

Dissolved phosphorus (P) from various sources contributes to periphyton growth in rivers. The Manawatu catchment is in the southern North Island, and since it flows through pastoral farmland with soft rock geology, it carries nitrogen, P and sediment that lead to growth of periphyton. We estimated long-term average sediment P in rivers in the catch...

In 1959, Athol Rafter began a substantial programme of monitoring the flow of 14 C produced by atmospheric thermonuclear tests through New Zealand’s atmosphere, biosphere and soil. By building on the original measurements through ongoing sampling, a database of over 500 soil radiocarbon measurements spanning 50 years has now been compiled. The da...

Using data from pastoral soils sampled by horizon at 56 locations across New Zealand, we conducted a meta-analysis. On average, the total depth sampled was 0.93±0.026 m (± SEM), and on a volumetric basis, the total C storage averaged 26.9±1.8, 13.9±0.6 and 9.2±1.4 kg C m−2 for allophanic (n=12), non-allophanic (n=40) and pumice soils (n=4), respect...

Excessive amounts of nutrients in rivers promote biological growth of periphyton and macrophytes to nuisance levels. Of most concern, because they are immediately available for growth, are dissolved inorganic forms of nitrogen (N) and phosphorus (P), primarily as nitrate-N and dissolved reactive phosphorus (DRP). To help understand the sources of d...

The ecosystem services approach to resource management considers all services provided by ecosystems to all sections of the community. As such, it could be used to assess sustainability of human development and equity in resource use. To facilitate the approach, tools are required at the level of detail at which policy and management decisions are...

Although erosion occurs under pastures in New Zealand North Island hill country, previous work shows that the soils on mid-slopes (> 19°) have large and significant average gains of soil carbon (C) and nitrogen (N) over a period of about 30 years. Both sheetwash erosion (from patches of bare soil) and soil deposition (from upslope) could have occu...

Reactive nitrogen (N)is increasingly added to the New Zealand environment because of increased sales of N fertilizer and increased human population. The Greenhouse Gas Inventory now reports in detail on changes for N losses from grazing animals from 1990 to 2010. Using animal numbers, we made assessments of N inputs and outputs for the 16 regions o...

Nitrogen (N) fertilizer increases pasture production in New Zealand in a near linear manner and affects pasture composition, soil below-ground communities and N losses. We monitored N fertilized plots established in long-term low-fertility pasture over different time periods to compare changes in N availability on below-ground soil communities (par...

We have examined the effects of both pH and phosphate concentrations on molybdate sorption by four Chilean Andisols with varying chemical properties. For both anions adsorption decreased with an increase in soil pH and also with organic matter content in the soils. In general, more phosphate than molybdate was sorbed by the soils. The Freundlich eq...

Planting of Pinus radiata D. Don in previously grazed pastures is a common land-use change in New Zealand. Although carbon (C) accumulates relatively rapidly in the trees, there have been no studies of the annual effect on soil C content during the early years of establishment. Here, we study soil properties under P. radiata and pasture each year o...

Ground-based harvest operations in planted forests can adversely affect the soil and subsequently the productivity of the plantation. This study examined the effects of compaction, site preparation, and fertilization on soil physical and chemical properties and tree growth in a trial established at a second-rotation harvest on an imperfectly draine...

Interactions between soil nutrient cycling processes are likely to influence N losses following disturbance in forest ecosystems. During a 340-day laboratory incubation, we examined C and N transformations in three sandy soils of different N status from Pinus radiata D. Don plantations before clear-cutting. The soils were a high N status Andisol (l...

Several of the major processes that result in N loss from soil (nitrification, ammonia volatilization, and denitrification) discriminate against N-15 and fractionate the stable N isotopes, thus delta N-15 of ecosystem components has been suggested as an indicator of ecosystem N leakiness. This concept has been applied more successfully to native sy...

Grazed pasture is New Zealand's predominant agricultural land-use and has been relatively recently developed from forest and native grasslands/shrub communities. From the 1850s onwards, land was cleared and exotic pastures established. Phosphorus fertilizer was increasingly used after 1950 which accelerated N fixation by clover. In the last two dec...

Previous re-sampling of 31 New Zealand pasture soil profiles to 1 m depth found large and significant losses of C and N over 2–3 decades. These profiles were predominantly on intensively grazed flat land. We have extended re-sampling to 83 profiles, to investigate whether changes in soil C and N stocks were related to land use. Over an average of 2...

Abstract. Several studies have provided compelling evidence that over long time scales of thousands to millions of years, and in the absence of catastrophic disturbances, ecosystem properties such as net primary productivity, decomposition, pedogenic processes, and nutrient cycling undergo substantial declines termed ecosystem retrogression. Retrog...

Increases in fertilizer inputs and livestock numbers affect plant species composition and richness; this in turn can affect the biodiversity of soil fauna and nutrient cycling in pastures. We selected two adjacent farmlets to study these effects. Since 1980, one farmlet (LF) had not received superphosphate fertilizer (SSP) and has a low stock densi...

Accurate measurement of dry bulk density is critical for determining stocks of elements such as carbon or nitrogen, in soils. During investigations of changes of soil carbon with time, we resampled soil profiles for bulk density using two methods, namely the driving hammer method and the carving method. The carving method involves gently pressing a...

In 1959, Athol Rafter began a substantial programme of monitoring the flow of 14C produced by atmospheric thermonuclear tests through New Zealand's atmosphere, biosphere and soil. The programme produced important publications, but also leaves a legacy of unpublished data critical for understanding soil C dynamics. A database of ~400 soil radiocarbo...

Quantitative information on the relationships between site quality and plantation productivity (dominated by the exotic species Pinus radiata) is required to achieve goals for sustainable forest production. Soil quality is a key component of site quality. A nationwide study of soil quality measurements is reported for 35 representative forest sites...

Data from a nationwide set of Pinus radiata D. Don plots established at a range of conventional stand densities were analysed at age 6 to (i) determine how environment and competition from weeds influence dynamic modulus of elasticity (E) of the lower stem base, (ii) develop a predictive multiple regression model of E for basal stemwood and (iii) i...

The CLUES model is an integrated catchment based model that designed to assist policy makers in understanding the implications of land use scenarios for water quality and a range of other indicators. CLUES integrates a number of existing models from several research providers, including SPARROW (catchment hydrology), OVERSEER and SPASMO (nutrient l...

We examined how a mixture of Pinus radiata D. Don and Cupressus lusitanica Mill. influences foliage element concentrations at 20 sites, covering a fertility gradient. Foliage element concentrations of plants at plot boundaries, where the two species grew adjacent to each other, were compared with those of plants at plot centres, where they were sur...

The OVERSEER® nutrient budgets model is increasingly being used by farmers and regional councils to assess N and P inputs and outputs from farms. There are, however, few data for low fertility and high fertility soils in hill country grazed by sheep. Two farmlets at AgResearch Ballantrae, near Woodville, with no-fertiliser (NF) and 375 kg ha-1 year...

A New Zealand data set of archived and resampled pasture soil profiles has identified a systematic pattern large soil C and N losses and gains that appear to be related to land-use intensity. We use isotope and organic geochemistry techniques in selected archived and resampled soil horizons to identify reasons for the observed large soil C and N lo...

Allophanic soils are known to accumulate organic matter, but the underlying mechanism is not well understood. Here we have investigated the sorption of humic acid (HA) by an allophanic clay in the presence of varied concentrations of either CaCl2 or NaCl as background electrolytes. Both the HA and the clay were separated from New Zealand soils. Muc...

A study has been conducted to provide information about the productive potential in the northern region of the Kapiti Coast District in New Zealand. The study aims at assisting the local community in long-term planning for the District Council, through their Long Term Council Community Plan (LTCCP). Horticultural enterprises have the potential to o...

New Zealand is committed to developing sustainable forest management practices as evidenced through Government involvement in international forestry agreements such as the Montreal Process, and the forestry sector's adoption of forest certification mechanisms. Despite this, there is little quantitative evidence of how plantation forestry affects si...

The Nanjing Declaration on Nitrogen Management calls for national governments to optimise N management by several strategies including assessment of N cycles. In New Zealand, reactive N continues to be added to the environment mainly by biological N fixation, and increasingly from N fertiliser additions. Here, we extend our work on N budgets in 200...

As erosion control and water conservation are almost always important issues, information on water use between different plantation species may be of significant management value for guiding decisions on species selection. The main and interactive effects of species and fertilisation on annual water loss and drainage in three-year old Cupressus lus...

Data taken from 261 4-year-old trees growing within a nationwide set of site quality plots where Pinus radiata D. Don and Cupressus lusitanica Mill. were established at high stand densities (40,000 stems ha−1) were analysed to (i) determine how site, species and fertilisation influence the wood properties basic density and green dynamic modulus of...

Since 1990, agricultural use of land in New Zealand has intensified and some areas have received increasing loads of phosphorus (P) fertilisers. This has led to increased concentrations of animal stock units on pastures. As both stock units and human populations increase, there is increasing concern about P loss from land and towns to waters. In or...

The objectives of this study were to determine the influence of site, fertilisation and age on fibre length and develop predictive models of fibre length from a comprehensive set of climatic, edaphic and stand variables. Data were collected from a nationwide set of 22 site quality plots where Pinus radiata D. Don was established at high stand densi...

Land-use in New Zealand poses risks to water quality in streams and lakes, yet there have previously been few tools used in New Zealand to predict the effects of land-use change at catchment to national scale. The CLUES spatial decision support system has been developed recently to assist with the assessment of land-use change on water quality, far...

Studies of changes in soil organic carbon (SOC) stocks normally limit their focus to the upper 20–30 cm of soil, yet 0–20 cm SOC stocks are only ∼40% of 0–1 m SOC. Accounting for only the upper 20–30 cm of SOC has been justifiable assuming that deeper SOC is unreactive since it displays 14C-derived mean residence times of hundreds or thousands of y...

The conversion of two-thirds of New Zealand's native forests and grasslands to agriculture has followed trends in other developed nations, except that pastoral grazing rather than cropping dominates agriculture. The initial conversion of land to pasture decreased soil acidity and elevated N and P stocks, but caused little change in soil organic C s...

The long-term nature of forest crop rotations makes it difficult to determine impacts of forestry on soil nutrients that might be depleted by forest growth. We used small scale, highly stocked plots to compress the length of the rotation and rapidly induce nutrient depletion. In the study, two species (Pinus radiata D. Don and Cupressus lusitanica...

A greenhouse study was conducted to determine if concentrations of fluoride (F), which would be added to acid soils via P fertilisers, were detrimental to barley root growth. Increasing rates of F additions to soil significantly increased the soil solution concentrations of aluminium (Al) and F irrespective of the initial adjusted soil pH, which ra...

Soil organic matter contains more C than terrestrial biomass and atmospheric CO2 combined, and reacts to climate and land-use change on timescales requiring long-term experiments or monitoring. The direction and uncertainty of soil C stock changes has been difficult to predict and incorporate in decision support tools for climate change policies. M...

Although density-specific stiffness, E/rho, (where E is Young's modulus and rho is wood density) is often assumed constant by the elastic similarity model, and in determination of critical buckling height (H(crit)), few studies have tested this assumption within species. Here this assumption is tested for Pinus radiata growing across an environment...

The Nanjing Declaration on Nitrogen Management, signed in Nanjing in October 2004, calls for national governments to optimize N management by several strategies including assessment of N cycles. Here we develop a first N budget for New Zealand (267,000km2), at both national and regional scales. The national inputs are estimated to be 36.5kg/ha, mai...

The reactions of phosphate with natural samples of allophane, ferrihydrite, hematite and goethite were measured for up to 30 d. The amount of phosphate sorbed on allophane showed the biggest increase with time whereas the amount sorbed on goethite showed the least increase with time. The total amount of phosphate sorbed either at high levels of pho...

The adsorption of oxalic acid on synthetic goethite (α‐FeOOH) was studied using adsorption isotherms. Infrared spectra were obtained for goethite‐oxalate complexes at several points on the isotherms. On a goethite preparation with a phosphate sorption capacity of 200|μmolg ⁻¹ the amounts of oxalate strongly adsorbed varied from near zero at pH 8 to...

Retention of ethylene glycol monoethylether (EGME) and ethylene glycol (EG), and sorption of nitrogen and water vapour, were studied on a wide range of soils from New Zealand and Fiji. EGME retention was mainly affected by the amount of EGME liquid present in the desiccator, the interaction with the desiccant (CaCl2), the amount of residual water i...

Adsorption isotherms, the infrared spectra of adsorbed species, and the amount of hydroxyl released when oxalate is adsorbed, all indicate that adsorption of oxalate, benzoate and phosphate at low solution concentrations occurs only on A1(OH)(H2 O) sites exposed on edge faces of the platy gibbsite crystals studied. This is confirmed by the finding...

The properties of contrasting soils occurring under a 1050–1600 mm rainfall gradient are described. The soils range, with increasing rainfall, from Typic Fragiaqualfs to Andic Dystrochrepts. Sand mineralogy of these soils indicates that they have formed in essentially similar parent materials consisting largely of quartzo-feldspathic loess with adm...

Data from a nationwide set of Pinus radiata site quality plots established at high stand densities and grown over a period of 4 years were analysed to (i) determine how site and fertiliser influence dynamic modulus of elasticity (E) of the stem at the tree base, and (ii) develop a predictive model of E for basal stemwood. Site had a highly signific...

New Zealand is committed to developing sustainable forest management practices as evidenced through Government involvement in international forestry agreements such as the Montreal Process, and the forestry sector's adoption of forest certification mechanisms. In support of this commitment, it has been identified that there is little quantitative e...

The growth of forest species in soil development chronosequences becomes increasingly phosphorus (P)-limited with time, as P is weathered, eroded and leached from soil. Foliar nitrogen (N) concentrations also tend to decrease with soil age when vegetation may be limited in both N and P. Here we report on soil development in temperate rain forests a...

Angiosperm trees often dominate forests growing in resource‐rich habitats, whereas conifers are generally restricted to less productive habitats. It has been suggested that conifers may be displaced by angiosperms except where competition is less intense, because conifer seedlings are inherently slow growing, and are outpaced by faster‐growing angi...

Legume-based pastures generally rely on soil biological activity to provide nitrogen (N) for plants. This study examined seasonal pasture growth in nine adjacent hill pastures, under sheep or beef, with different long-term managements, including certified organic, no fertilizer, and conventional fertilizer application, that formed a soil-fertility...

The aim of this study was to examine how shifts in soil nutrient availability along a soil chronosequence affected temperate rainforest vegetation. Soil nutrient availability, woody plant diversity, composition and structure, and woody species leaf and litter nutrient concentrations were quantified along the sequence through ecosystem progression a...

Globally, soil organic matter contains approximately 1500 Pg C to 1 m soil depth and 2300 Pg C to 3 m depth—more than biomass and atmospheric CO 2 combined. Efforts to account for the effects of land-use or vegetation change on soil organic carbon (SOC) stocks normally limit their focus to the upper 20–30 cm of the soil profile, yet 0–20 cm SOC sto...

Globally, land-use change is occurring rapidly, and impacts on biogeochemical cycling may be influenced by previous land uses. We examined differences in soil C and N cycling during long-term laboratory incubations for the following land-use sequence: indigenous forest (soil age = 1800 yr); 70-year-old pasture planted after forest clearance; 22-yea...

Soil organic C is often suggested as an indicator of soil quality, but desirable targets are rarely specified. We tested three approaches to define maximum and lowest desirable soil C contents for four New Zealand soil orders. Approach 1 used the New Zealand National Soils Database (NSD). The maximum C content was defined as the median value of lon...

The conversion of hill country pastures to exotic forest plantations has occurred rapidly in New Zealand over the last 10 years. This land-use change affects properties of the mineral soil, especially nitrogen (N) cycling. Here we studied the changes in soil in situ N mineralisation, in leaching, and microbial biomass, when Pinus radiata D. Don is...

Nitrogen (N) is the major nutrient that limits pasture growth in New Zealand. Here we test the hypothesis that N supply to herbage from soil microbial mineralization is a function of both the quantity and quality of the soil organic matter, and that this underlying process is similar under conventional and organic management. Preliminary results fo...

We have investigated the sorption of Cu and Cd by allophane and its complexes with a soil humic acid (HA), varying in carbon content from 14–123 g kg−1. The sorption of Cu and Cd was measured at pH 5.0 and 5.5, using the batch technique and a single concentration (2mM) of Cu or Cd in the presence of LiClO4. The sorbed metals were partly desorbed by...

Following the tree harvest, the biogeochemistry of a catchment is modified by changes in soil temperature and moisture, and nutrient cycling. We monitored soil-solution and stream-water chemistry, and soil properties in a Pinus radiata D. Don plantation in New Zealand before and after clear-cutting and replanting in 1997. The annual rainfall during...

Total organic carbon (C) and natural ¹³C abundance were measured in adjacent allophanic soils (Andisols) and non-allophanic soils (Inceptisols) under maize (Zea mays L.) and ryegrass pasture (Lolium perenne L.) to assess the C turnover rate in soils of contrasting mineralogy and specific surface area. The allophanic soil contained more total C than...

Given recent negotiations of the Committee of Parties to the United Nations Framework Convention on Climate Change, soil C accumulation related to soil conservation efforts may be counted as C credits in national C balance calculations under the Kyoto Protocol. It has been proposed that in some instances, erosion can establish a dynamic equilibrium...

The stabilization of organic matter in soil by interaction with aluminium (Al) or allophane is important in maintaining soil quality, and in retarding the decomposition of soil organic matter. Complexation of Al by soil organic matter may also ameliorate Al toxicity. Here we use 13C-NMR spectroscopy to assess the interaction of soil organic matter...

Following tree harvest, the nitrogen (N) cycle is modified by changes in plant uptake, substrate availability, soil temperature and moisture. We used 15N labelled needles and small-wood (5–10mm diameter) from Pinus radiata D. Don in a 30-month field incubation at two contrasting sites to follow decomposition processes after clear-cutting and replan...

To ensure the sustainability of land systems in terms of nutrient cycling and maintenance of soil physical conditions, there is a need to understand soil organic matter (SOM) and its dynamics. It has been suggested that soil-carbon (C) models developed internationally do not perform well under New Zealand's unique climatic and soil mineralogical co...

The measurement of the specific surface area of soils may be useful for ranking soils in their ability to sorb polar compounds such as some pesticides and pollutants. For A horizons with varied mineralogy, particularly those containing large amounts of soil organic matter, this is problematic. We have estimated the surface area of a range of topsoi...

We conducted a 7-week laboratory incubation experiment to evaluate the effect of leaching on net C and N mineralisation in soils. The soils were collected from adjacent fields of long-term pasture and maize, where each field contained an Inceptisol and an Andisol. The concentration of clay mineral was 200 g/kg halloysite in the Inceptisol and 120 g...

Since the 1930s, large areas of marginally productive pasture and/or scrubland have been converted to plantation forests dominated by Pinus radiata. In the 1990s, up to 100,000 hectares of new plantings occurred each year, many into land used previously for pasture. Current plantation forest area is about 1.7 million hectares. This land-use change...

Although several studies have quantified either C mineralisation or net N mineralisation in particle-size fractions, no work has examined simultaneous C and net N mineralisation. Therefore, we conducted an 18-week laboratory incubation to compare simultaneous mineralisation in sand, silt, and clay fractions. The soils (silt loams) were collected fr...

Soil organic matter is a major component of biogeochemical cycles and is important in maintaining soil quality. We investigated relationships between soil organic C and various soil and site properties that may influence long-term soil C accumulation across a range of soil orders in New Zealand. We used pedon and climatic data for 167 pedons under...