Centre for Soil and Environmental Research

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  • PublicationOpen Access
    Effect of soil moisture status and animal treading on N₂O emissions and the effectiveness of a nitrification inhibitor mitigation technology
    (New South Wales Department of Primary Industry, 2013-09) Di, Hong J.; Cameron, Keith C.; Ball, B.; Podolyan, Andriy; He, J.; Michalk, D. L.; Millar, G. D.; Badgery, W. B.; Broadfoot, K. M.
    Nitrous oxide (N₂O) is a potent greenhouse gas with a long term global warming potential about 298 times that of carbon dioxide (CO₂). In grazed grassland, most of the N₂O is emitted from nitrogen (N) excreted by the grazing animal, particularly in the animal urine. When the soil is wet, such as that in winter grazing conditions, animal grazing can cause soil structural damage, leading to soil compaction. The combination of a wet soil plus soil compaction is particularly conducive for N₂O production. A nitrification inhibitor technology using dicyandiamide (DCD) has been developed to reduce N₂O emissions from grazed grassland (Di and Cameron 2002; 2003). However, the efficacy of this technology under wet and compact soil conditions has not been well studied. The objectives of this study were to determine: (1) The impact of soil moisture content on the abundance of ammonia oxidizers and N₂O emissions; (2) the impact of animal treading on N₂O emissions; and (3) The effectiveness of the nitrification inhibitor DCD in reducing N₂O emissions, as affected by soil moisture status and animal treading.
  • PublicationOpen Access
    Urine patch area coverage of an intensively stocked dairy pasture
    (Lincoln University., 2010-08) Moir, James L.; Cameron, Keith C.; Di, Hong J.; Fertsak, Ulrike
    The objective of this study was to develop a new method to quantify seasonal and annual urine patch area coverage under an intensive dairy farming system.
  • PublicationOpen Access
    15N and 18O values of soil emitted N2O from a New Zealand pasture amended with lactose-depleted dairy factory effluent and urea - preliminary results
    (Lincoln University. Centre for Soil and Environmental Quality) Ford, Christopher I.; Bol, R.; Clough, Timothy J.; Sherlock, Robert R.; Di, Hong J.; Cameron, Keith C.
    The study presents some preliminary data of the influence of LD-DFE on the 18O and 15N values of N2O from a New Zealand pasture soil.
  • PublicationOpen Access
    The spatial distribution and area coverage of urine depositions in grazed pastures in NZ
    (Lincoln University., 2006) Moir, James; Fertsak, Ulrike; Cameron, Keith; Di, Hong
    In grazed pasture systems, grazing animals deposit urine and dung causing high nutrient loading to a relatively small proportion of the total grazed area. The majority of ingested nitrogen (N) is excreted in urine, and high N loading in the urine patch is of particular environmental concern because of the potential for leaching of soil nitrate N from the patch and the subsequent potential degradation of ground and surface water quality. Animal stocking rate and stock type are key factors driving the quantity of nutrient, especially N, which may be deposited as urine and dung to pasture soils. Therefore the total paddock area receiving urine deposits in any time period is critical to the understanding of nutrient cycling and nutrient loss in grazed pasture systems. Some theoretical estimates of this critical area coverage value have been made by researchers, but quantitative field spatial data is scarce and seasonal components have often been ignored in earlier estimates. Consequently, much variability and uncertainty still surrounds the current estimate of annual urine patch area coverage in grazed pasture systems, and how area coverage varies with different stocking rates and stock type. A new method using global positioning system (GPS) and geographic information system (GIS) technology was developed and successfully used to quantify the spatial distribution and area coverage of urine patches deposited by grazing animals. Accurate measurements of urine patches over a period of twelve months were made for two farm types, which are typical of New Zealand grazed pasture systems: (i) an irrigated dairy farm and (ii) a sheep and beef hill country farm. At two field sites urine patch areas were visually identified from the enhanced pasture growth in those areas and their area and spatial location recorded with GPS at regular time intervals. The GPS data was analysed in a GIS system. These data were then used to calculate seasonal and annual urine patch coverage in the paddocks on an area basis. On the dairy farm at an effective stocking rate of 3.5 cows ha-1 (c. 32 standard stock units [ssu] ha-1) the observed annual urine patch area coverage was 22%. The mean urine patch radius was 30.5 cm. Mean urine patch radius ranged from 27 to 35 cm between seasons. The observed average urine patch area was 0.28 m2. Urine patch coverage was shown to increase with increased stocking rate (cows ha-1 or cow grazing days). For the sheep and beef farm at an effective stocking rate of 15.1 ssu ha-1 the observed annual urine patch area coverage was 16.8% for the study paddock. Average urine patch coverage was 19.3% and 14.3 % on flat areas (0 – 3°) and hill slopes (7 – 15°) respectively. This result confirms that a higher grazing pressure occurred on flat areas than on hill slopes. For the observed one-year period, the mean urine patch radius was 25 cm. Mean urine patch radius ranged from 19 to 29 cm between seasons. The observed average urine patch area was 0.19 m2. This study has successfully used GPS and GIS technology to make initial measurements of the spatial distribution and area coverage of urine depositions in grazed dairy and sheep and beef pastures in New Zealand. Field measurements for this study are ongoing.
  • PublicationOpen Access
    Verification of the implementation of CWM1 in the HYDRUS Wetland Module
    (Lincoln University, 2013) Palfy, Tamas Gabor
    The Constructed Wetland Model N°1 (CWM1) is a numerical biokinetic model describing microbial transformation and degradation processes in subsurface flow constructed wetlands. In this master thesis the CWM1 implementation in the HYDRUS wetland module was verified using data from previously conducted controlled environment column experiments. These twenty day long batch experiments used synthetic wastewater and three different plant species (Carex rostrata Stokes, Schoenoplectus acutus Muhl. Ex Bigelow and Typha latifolia L.) in addition to unplanted replicates at four different temperatures. The minimum number of adjusted parameters between the sixteen simulated columns was targeted, and it was found that: (1) initial bacterium concentrations, (2) initial adsorbed ammonia nitrogen concentrations, and (3) root oxygen loss rate for each simulation inevitably needed to be set separately. For all other parameters the same values have been used. Some biokinetic parameters had to be adapted during calibration to match measured data. This was required to allow anaerobic, anoxic and aerobic processes to run parallel and explained by the local effect of root zone re-aeration. The simulation results were evaluated by conventional visual and numerical and a new goodness of fit analysis method, deflection analysis. The new method was introduced to compare simulations to measured data with standard deviation. Simulated contaminant concentrations had a very good fit to measured values of NH₄-N and SO₄-S and a reasonable good fit to measured values of COD versus time.
  • PublicationOpen Access
    Final report: Review of New Zealand Specific FracGASM and FracGASF Emissions Factors
    (2009-01) Sherlock, Robert R.; Jewell, P.; Clough, Timothy J.
    FracGASM and FracGASF are important factors within national nitrous oxide (N₂O) emissions inventories. These factors represent the proportions of manure-N and fertiliser-N respectively that are released into the atmosphere, principally as ammonia, NH₃, to become indirect sources of N₂O when re-deposited on land surfaces elsewhere. Currently the NZ N₂O inventory uses the IPCC defaults of 0.2 and 0.1 for FracGASM and FracGASF respectively. The use of 0.2 for FracGASM in New Zealand’s N₂O inventory recently came under the scrutiny of the ‘Expert Review Team’ (ERT) of the United Nations Framework Convention on Climate Change (UNFCCC) secretariat. Amongst other things, the ERT encouraged NZ to: “investigate a country-specific FracGASM or document why the IPCC default value is considered appropriate for New Zealand conditions”. This current review forms part of that investigation. In this review we have attempted to locate and scrutinise all (mostly field-based) studies of relevance to the magnitudes of FracGASM and FracGASF as used in NZ’s current N₂O inventory. Following a brief introduction (section 1) sections 2 and 3 focus on the factors influencing the production and emission of NH₃(g) and NOx(g) from soils and also provide an overview of the techniques employed for their measurement. Sections 4 and 5 then focus respectively on international and local (NZ) studies of relevance to FracGASM. In section 6 we review international and NZ data on NH₃(g) emissions from mainly urea and diammonium phosphate fertilisers and then follow that in section 7 with a review of NOx emissions from animal excreta and fertiliser applied to pasture. Section 8 summarises all major findings and recommendations.
  • PublicationOpen Access
    The effects of urea and ammonium sulphate nitrate (ASN) on the production and quality of irrigated dairy pastures in Canterbury, New Zealand
    (Fertilizer and Lime Research Centre, Massey University, 2003-12) Moir, James L.; Cameron, Keith C.; Di, Hong J.; Roberts, A. H. C.; Kuperus, W.
    This paper examines the effects of two different forms of nitrogen (N) fertiliser, urea and ammonium sulphate nitrate (ASN) on the production and quality of spray irrigated dairy pastures in Canterbury. Pasture production and a wide range of pasture quality parameters were measured in a mowing trial of randomised design on the Lincoln University dairy farm. Treatments consisted of three fertiliser forms (urea, urea plus sulphur (S) and ASN) applied at two annual rates ofN (150 and 250 kg N ha⁻¹). Measurements included pasture dry matter (DM) yield, botanical composition, pasture N and S uptakes, 'standard' pasture quality measurements, such as carbohydrate and protein levels, and a detailed assessment of levels of individual proteins in the pasture. Under the conditions of this trial representing typical centre-pivot irrigation and high soil fertility, the total annual dry matter yield ranged from 15.9 (Control) to 19.4 (ASN 250) t DM ha⁻¹ and was strongly influenced by rate of N fertiliser application but not fertiliser type. ASN showed a small significant yield advantage (P < 0.05) over urea at the 150 N rate but not at the 250 N rate. Clover levels did not vary significantly with type or rate of fertiliser applied. Pasture quality, as measured by 'key' quality indicators was generally unaffected by fertiliser treatments throughout the season, although some differences in specific amino acid levels were detected. The implications of the impacts of N fertiliser use on pasture quality are discussed.
  • PublicationOpen Access
    Fractionation of copper, nickel, and zinc in metal-spiked sewage sludge
    (American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, 2001) McLaren, R; Clucas, L
    The enrichment or spiking of sewage sludge with heavy metals for experimental purposes is a fairly widely used, although sometimes controversial, technique. A study was undertaken, using a sequential fractionation scheme, to assess the degree of incorporation of Cu, Ni, and Zn into sewage sludge samples spiked with these metals and incubated for 6 mo. For all three metals, substantial proportions of the metals were incorporated into the sludge matrix, particularly as evidenced by their occurrence in the oxide-bound, organic-bound, and residual fractions. In particular, for Cu very little of the added copper remained in the sludge supernatant solution after 6 mo of incubation and, apart from at the highest level of Cu addition, there was very little difference in the fractional distribution of Cu between the Cu-spiked and non-Cu-spiked sludges. For Ni and Zn, however, although there was substantial incorporation of these metals into the sludge, the higher levels of Ni and Zn addition resulted in greater proportions of the metals in the most soluble fractions (soluble, exchangeable, specifically sorbed) compared with nonspiked sludges. The fractionation data for Ni also showed that large additions of Cu and Zn can affect the fractional distribution of Ni in the sludge. The drying of sewage sludge prior to analysis was shown to increase metal solubility in the sludge samples, and the potential implications of this finding for the prediction of sludge metal bioavailability are discussed.
  • PublicationOpen Access
    Fungal inoculum properties : Extracellular enzyme expression and pentachlorophenol removal by New Zealand Trametes species in contaminated field soils
    (American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, 2007) Ford, C; Walter, M; Northcott, G; Di, Hong; Cameron, Keith; Trower, T
    This study was conducted to improve the ability of indigenous New Zealand white-rot fungi to remove pentachlorophenol (PCP) from contaminated field soil. The effects of different bioaugmentation conditions on PCP removal and extracellular enzyme expression were measured in the laboratory. The conditions were fungal growth substrate and co-substrate composition, culture age, and Tween 80 addition to the contaminated soil. The fungi used were Trametes versicolor isolate HR131 and Trametes sp. isolate HR577. Maximum PCP removal was 70% after 7 wk from a 1043 mg kg⁻¹ PCP-contaminated soil inoculated with an 11-d-old fungal culture of T. versicolor isolate HR131. There was minimal production of undesirable pentachloroanisole by the fungi. Tween 80 addition had no affect on PCP removal. Poplar sawdust was more suitable as a fungal growth substrate and a co-substrate amendment for PCP removal and extracellular enzyme expression than the locally available pine and fir sawdust. Pentachlorophenol removal was not necessarily correlated with extracellular enzyme expression. The research results demonstrate that PCP biodegradation was affected by inoculum culture age, by the presence of a co-substrate amendment, and by growth substrate composition after white-rot fungal bioaugmentation into PCP-contaminated field soils.
  • PublicationOpen Access
    Fungal inoculum properties : Extracellular enzyme expression and pentachlorophenol removal in highly contaminated field soils
    (American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, 2007) Ford, C; Walter, M; Northcott, G; Di, Hong; Cameron, Keith; Trower, T
    This study was conducted to improve the pentachlorophenol (PCP) bioremediation ability of white-rot fungi in highly contaminated field soils by manipulating bioaugmentation variables. These were the dry weight percentage of fungal inoculum addition (31–175 g kg⁻¹), PCP concentration (100–2137 mg kg⁻¹ PCP), fungal inoculum formulation, and time (1–7 wk). Five fungal isolates were used: the New Zealand isolates Trametes versicolor (L.: Fr.) HR131 and Trametes sp. HR577; the North American isolates Phanerochaete chrysosporium Burds. (two isolates) and Phanerochaete sordida (Karst.) Erikss. & Ryv. Pentachlorophenol removal, manganese peroxidase, and laccase activity, and the formation of chloroanisoles in the contaminated field soils were measured. The majority of PCP removed by the Trametes isolates was in the first week after bioaugmentation. The maximum PCP removal by the fungi varied from 50 to 65% from a 1065 mg kg⁻¹ PCP contaminated field soil. Pentachlorophenol was preferentially converted to pentachloroanisole (PCA) by the Phanerochaete isolates (>60%), while 2 to 9% of the PCP removed by two Trametes isolates was converted to PCA. A pH increase was measured following bioaugmentation that was dependent on PCP concentration, fungal inoculum addition, and formulation. This, together with rapid initial PCP removal, possibly changed the bioavailability of the remaining PCP to the fungi and significantly decreased the sequestering of PCP in the contaminated field soils. The research supports the conclusion that New Zealand Trametes spp. can rapidly remove PCP in contaminated field soils. Bioavailability and extractability of PCP in the contaminated field soil may significantly increase after bioaugmentation.
  • PublicationOpen Access
    Reducing nitrate leaching losses from a Taupo pumice soil using a nitrification inhibitor eco-n
    (New Zealand Grassland Association, 2007-11) Cameron, Keith C.; Di, Hong J.; Moir, James L.; Roberts, A. H. C.
    The decline in water quality in Lake Taupo has been attributed to nitrogen (N) leaching from surrounding land areas. Pastoral agriculture has been identified as a significant contributor to this N transfer to the lake through animal urine deposition. There is therefore an immediate need for new management options to reduce N losses. The objective of this study was to measure the effectiveness of using a nitrification inhibitor (eco-n) to reduce nitrate leaching losses from a pasture soil of the Taupo region. A 3-year study was conducted using twenty lysimeters on Landcorp's 'Waihora' sheep and beef farm, within 10 km of Lake Taupo. The results show that animal urine patches were the main source of nitrate leaching (>95% of the total annual loss) and that eco-n significantly (P<0.05) reduced nitrate leaching losses from urine treated lysimeters. When the lysimeter results were combined with a detailed GPS survey and GIS analysis of urine patch coverage of the farm it is concluded that eco-n reduced annual nitrate leaching losses by between 23 and 32%, with an average reduction of 27%. Thus eco-n represents a practical technology that pastoral farmers could adopt today, to assist them to meet new water quality standards in sensitive catchments near Lake Taupo and the upper Waikato River.
  • PublicationOpen Access
    Using nitrogen : what is best practice?
    (South Island Dairy Event (SIDE), 2005-06) Cameron, Keith C.; Di, Hong J.; Moir, James L.; Christie, R.; Pellow, R.
    Feed shortages occur in spring because the rate of pasture growth is below the cow demand. Spring pasture growth rate is slow in the South Island because the soil temperature is low and the rate of nitrogen (N) supply from the soil to the plant is also slow. Until recently the only option available to increase the nitrogen supply to pasture plants during the spring was to apply nitrogen fertiliser. However, the development of eco-n nitrification inhibitor technology for pastures opens up a new avenue for increasing the nitrogen supply in spring by reducing the nitrogen losses from the soil over winter. This paper discusses best practice use of nitrogen fertilisers and the benefits of using eco-n nitrification inhibitor technology.
  • PublicationOpen Access
    Clean and green with 'eco-n'
    (South Island Dairy Event (SIDE)., 2004-06) Cameron, Keith C.; Di, Hong J.; Moir, James L.; Christie, R.; Van, D. W. T.
    Lincoln University and Ravensdown Fertiliser Co-operative have developed a new soil treatment technology, called 'eco-n' technology, that can reduce the environmental impacts of dairy farming and at the same time help farmers to grow more grass. Research shows that eco-n can: reduce nitrate leaching by 60 per cent; reduce potassium, calcium and magnesium leaching by more than 50 per cent; reduce nitrous oxide emissions (a potent greenhouse gas) by 80 per cent; and increase pasture production by over 10 - 12 per cent per year. This paper will cover the science behind the eco-n technology and the practical application and economics of using eco-n technology.
  • PublicationOpen Access
    Improved nitrogen management with eco-n nitrification inhibitor : an example of "growing for good"
    (New Zealand Large Herds Association, 2005-04) Cameron, Keith C.; Di, Hong J.; Moir, James L.; Christie, R.; Pilbrow, R.
    The recent report by the New Zealand Parliamentary Commissioner for the Environment, called "Growing for Good", highlighted the adverse impacts that nitrate leaching can have on water quality. It called for a 'redesigning for sustainability' of New Zealand farming in order to reduce the impacts of intensive farming and achieve more sustainable farming systems. Reducing the leaks in the nitrogen cycle provides an opportunity to reduce the impact of dairying on the environment. The development of a new soil treatment method, called eco-n technology, can be used to improve the efficiency of the nitrogen cycle, reduce the environmental impacts of dairy farming and at the same time increase farm productivity. The development of 'eco-n' technology by Lincoln University and Ravensdown Fertiliser Co-operative Ltd is therefore a significant step towards 'redesigning for sustainability'. Our research results show that eco-n can: reduce nitrate leaching by 60%; reduce cation leaching by 50%; reduce nitrous oxide emissions (a potent greenhouse gas) by 75%; increase spring pasture production by 20%; and increase annual pasture production by 15% per year. This paper will cover the science behind the development of eco-n technology and the practical application of using eco-n technology.
  • PublicationOpen Access
    Fractionation of arsenic in soil by a continuous-flow sequential extraction method
    (American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, 2001) Shiowatana, J; McLaren, R; Chanmekha, N; Samphao, A
    Batch sequential extraction techniques for fractionating metals or metalloids in soils are time consuming and subject to several potential errors. The development of a continuous-flow sequential extraction method for soil As is described and assessed, having the benefits of simplicity, rapidity, less risk of contamination, and less vulnerability to changes in extraction conditions compared with traditional batch methods. The validated method was used to fractionate soil As using water, NaHCO₃, NaOH, and HCl, followed by digestion of the residue with HNO₃, and HF acids. The extracts and digests were analyzed for As by graphite furnace atomic absorption spectrometry. Good recoveries of total soil As (97–115%) were obtained and fractionation data generally comparable with those obtained using conventional batch techniques. Soils from a tin-mining area in Thailand and soils from As-contaminated cattle (Bos taurus) dip sites in Australia were used to test the applicability of the method, and to demonstrate the usefulness of the extractogram obtained. The ability to produce detailed extractograms for As and other elements (Al, Fe, and Ca) enabled an examination of elemental associations in individual fractions. With the exception of As extracted with HCl, the extractograms generally support previous suggestions of the likely forms or associations of As present in the different soil fractions.
  • PublicationOpen Access
    Seasonal fluctuations in phosphorus loss by leaching from a grassland soil
    (Soil Science Society of America, 2004) Toor, G; Condron, L; Di, Hong; Cameron, Keith
    Phosphorus losses from soils have been reported to impair the water quality, resulting in deaths of fish and other marine animals, and can harm human health. The objective of this study was to determine the seasonal distribution of P forms and losses in leachate collected from intact soil monoliths (70-cm depth, 50-cm diam.) of a Lismore stony silt loam soil (fine-loamy, mixed, superactive, frigid Aquic Cumulic Hapludoll) during a 2-yr period. The experiment included different combinations of mineral P fertilizer at 45 or 90 kg P ha⁻¹ yr⁻¹ and/or farm dairy effluent (FDE) at 200 or 400 kg N ha⁻¹ yr⁻¹, which contained 41 to 95 kg P ha⁻¹ yr⁻¹. Amounts and forms of P in leachate collected during the irrigation (IR; November–April) and nonirrigation (NIR; May–October) seasons were compared. Results showed that P losses were higher in particulate forms (mainly particulate unreactive phosphorus, PUP) during the IR seasons. This may be because of regular inputs of high intensity flood IR (92 mm per application), which increased the dislocation of particles in the soil profile, thereby resulting in higher PUP losses. On the other hand, the amount of natural rainfall was much lower (usually <20 mm per event) during the NIR seasons that resulted in less dislocation of particles compared with the IR seasons; hence, lower P losses as PUP but higher losses as dissolved unreactive phosphorus (DUP). Variation in P losses during the different seasons suggest the need to develop mitigation strategies that should focus on reducing DUP losses during the NIR and PUP losses during the IR season.
  • PublicationOpen Access
    Phosphorus exchangeability and leaching losses from two grassland soils
    (American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, 2002) Sinaj, S; Stamm, C; Toor, G; Condron, L; Hendry, T; Di, Hong; Cameron, Keith; Frossard, E
    Although phosphate phosphorus (P) is strongly sorbed in many soils, it may be quickly transported through the soil by preferential flow. Under flood irrigation, preferential flow is especially pronounced and associated solute losses may be important. Phosphorus losses induced by flood irrigation were investigated in a lysimeter study. Detailed soil chemical analyses revealed that P was very mobile in the topsoil, but the higher P-fixing capacity of the subsoil appeared to restrict P mobility. Application of a dye tracer enabled preferential flow pathways to be identified. Soil sampling according to dye staining patterns revealed that exchangeable P was significantly greater in preferential flow areas as compared with the unstained soil matrix. This could be partly attributed to the accumulation of organic carbon and P, together with enhanced leaching of Al- and Fe-oxides in the preferential flow areas, which resulted in reduced P sorption. The irrigation water caused a rapid hydrologic response by displacement of resident water from the subsoil. Despite the occurrence of preferential flow, most of the outflowing water was resident soil water and very low in P. In these soils the occurrence of preferential flow per se is not sufficient to cause large P losses even if the topsoil is rich in P. It appears that the P was retained in lower parts of the soil profile characterized by a very high P-fixing capacity. This study demonstrates the risks associated with assessing potential P losses on the basis of P mobility in the topsoil alone.