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Kenaf leaves are one of the kenaf parts which has a high potential to be utilized as a tea leave infusion in Malaysia. Kenaf leaves are known to have high antioxidant properties. Kenaf leaves tea (KLT) can be prepared through a simple process, however, the consumer perception of the uses of KLT was not evaluated in the Malaysian market. In this study, the antioxidant properties were evaluated through in-vitro gastrointestinal digestion (GID). It was proven that KLT contains a high amount of total phenolic and flavonoid content, tested using DPPH, ABTS and FRAP assays. Although the antioxidant properties were digested throughout simulated gastro and intestine digestion, their content remained quite high after the digestion. Therefore, KLT should have a high potential to be introduced to the Malaysian market. The consumer perception survey obtained a total of 397 responses and it was clear that Malaysians frequently consume tea products at least once a week. Most consumers preferred a slightly sweet and light-coloured tea. While the majority of the respondent was not aware of the existence of KLT, their market acceptability was high as there were 47.4% of respondents chose to try KLT product once it is made available in the market. KLT made from the freeze-drying technique preserved the antioxidants properties, and KLT market potential was proven relatively high due to consumer perception of KLT was similar to commonly available tea products.

Due to the increase in global demand for palm oil products, the oil palm industry has continued to expand in the past decades. Continuous production of fresh fruit bunches in oil palm plantation is essential to meet this growing demand. Meanwhile, the productivity of plantations is highly dependent on the supply of resources (e.g., water, fertilisers and sunlight) and on proper plantation management systems. The harvested fresh fruit bunches from oil palm plantations have to be immediately sent to palm oil mills to ensure the quality of the crude palm oil and crude palm kernel oil. In this study, oil palm plantation operations are optimised using an input–output model to determine maximum yield with minimum plantation size and greenhouse gases emissions. Multiple scenarios can be incorporated in the proposed model. To illustrate the proposed model, a case study of an oil palm plantation supplying fresh fruit bunches for a 60 t/h capacity palm oil mill in Malaysia is presented. Various plantation management practices with different resources supply constraints are considered. Based on the optimised result, the sustainability of a plantation is greatly improved. The plantation area needed to meet the requirement of the palm oil mill is reduced by 24% when using combined organic and inorganic fertilisers. A significant drop in greenhouse gases emissions from 282.95 to 200.73 kt CO2e/y can thus be achieved. This result implies that widespread use of such optimal practices can help meet growing global demand without the need to convert pristine ecosystems into new plantations.

Legume-based pastures in Australasia are predominantly perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.). These pastures have disadvantages such as limitations in the production and persistence of white clover and ryegrass in drought prone regions. With the increasing interest in organic agriculture, more complex pasture mixtures are seen as an alternative to the standard ryegrass-white clover (RWC) pasture. Although anecdotal evidence exists to support the benefits of alternative pastures, there is insufficient scientific evidence to support or refute these claims. The present study was conducted to compare three different alternative multi-species (mixed herb leys) (MSP) pastures with the standard RWC pasture with and without irrigation, in terms of biomass and biological nitrogen fixation (BNF) over a period of 1 year under field conditions in Canterbury, New Zealand. Isotopic dilution technique involving field 15N-microplots were used to measure BNF. Irrigation doubled dry matter yields (DMY) of all pastures compared with those under dryland. There was no significant difference between DMY of all pastures under dryland. However, under irrigation, MSP pastures out-yield RWC pasture in total and legume DMY. Red clover MSP produced significantly lower DMY than the comprehensive or lucerne MSP treatment, probably due to the ability of lucerne in extracting water from deeper soil depth. Seasonal changes in plant composition varied according to the species sown, soil moisture status and temperature. Total and seasonal amounts of N2 fixed followed the same trend as the DMY and were related to the DMY of legumes. On average, about 26–34 kg N was fixed per tonne of legume DMY, showing a uniformity across all pastures. Overall, based on the present results of 1-year study, the MSP pastures tend to result in higher DMY, BNF and legume growth compared with that of the RWC pasture, provided irrigation is available. With increased BNF, these irrigated MSP pastures may provide high quality feed to grazing animals.

Relationships among; soil organic matter (SOM), the feeding activity of the soil-dwelling scarab larva, Costelytra zealandica (White) (Coleoptera: Melolonthidae), amber disease and soil numbers of its causal agent, Serratia entomophila (Enterobacteriaceae), were studied. C. zealandica larvae may cause severe damage to pasture roots and reduce ryegrass and clover production. Entomopathogenic strains of S. entomophila are being used in a biocontrol programme in New Zealand as they induce inhibition of larval feeding activity and larval death 1–3 months from the onset of infection. A mature (38-year-old) and a young (4-year-old) pasture from Canterbury, New Zealand, were chosen for this study. Both pastures had the same soil type, very similar agronomic practices but different ages and therefore SOM contents. Soil from both sites was collected and amounts of C and N of different fractions of SOM were measured. Organic matter was 7.59% and 4.41% in the mature and young pastures respectively. Total C and N in soil and most fractions of SOM were significantly higher in the mature pasture than in the young pasture. Total C and N present in cold and hot water extractions combined, representing the labile SOM fraction, showed 45% less C and 37% less N in the soil from the young pasture than in the soil from the mature pasture. In both soils, approximately 10% of the total C and N was present in the labile SOM fractions. Populations of soil-borne indigenous bacteria, S. entomophila, were estimated in fresh and air-dried samples from both pastures. Soils from the two pastures contained a significantly different number of S. entomophila cells. A more than ten times higher population was present in fresh soil from the mature pasture compared with fresh soil from the young pasture. However, levels of S. entomophila decreased significantly when the soil was air-dried for experimental purposes. An experiment was designed to explore the interactions occurring among SOM quantity and quality, S. entomophila performance as a biocontrol agent and simulated root feeding activity of early third instars of C. zealandica. Larvae were placed individually in pots containing air-dried soil from one or other of the two pastures (n = 10 per treatment). The experimental pots were inoculated at three dose rates of a pathogenic strain of S. entomophila. The control pots were treated with nutrient broth free of S. entomophila. All pots were incubated in the laboratory under the same experimental conditions. Larval feeding activity was measured using pieces of carrot root. All pots were examined for infection, mortality, feeding rate and gain in live weight of each larva after 15 and 30 days. The mature pasture was associated with significantly higher amber disease and mortality than the young pasture. Also, a significantly higher gain in larval weight was observed in the young pasture soil, together with a higher rate of carrot consumption by larvae. It can be concluded that the content of labile SOM in both pastures may account for the differences observed in this study and could have a buffering effect on plant damage caused by soil-dwelling scarab larvae.

Effects of the herbicide metsulfuron-methyl on soil microorganisms and their activities in two soils were evaluated under laboratory conditions. Measurements included their populations, soil respiration, and microbial biomass. In the clay soil, bacterial populations decreased with increasing concentration of metsulfuron-methyl during the first 9 days of incubation but exceeded that of the control soil from day 27 onward. In the sandy loam soil, the herbicide reduced bacterial populations during the first 3 days after application, but these increased to the level of untreated controls after 9 days' incubation. Fungal populations in both soils increased with increasing metsulfuron-methyl concentrations, especially in the sandy loam soil. CO 2 evolution was stimulated in both soils in the presence of the herbicide initially, but decreased during days 3 to 9 of the incubation period before increasing again afterward. The presence of metsulfuron-methyl in the soil increased microbial biomass, except in sandy loam soil at the first day of incubation.

The major inputs of nitrogen (N), phosphorus (P) and sulphur (S) as fertilizer and biological N2 fixation, and the major removals of these nutrients in harvested products (grain, meat and wool) for each year of the rotation of three pairs of farms were calculated. The farms were under a mixed cropping system of farming, common to the study area, in which grazed grass/white clover pasture and/or grass and white clover seed crops are grown in rotation with arable crops. One of each pair of farms was managed conventionally and the other was under an alternative organic or biodynamic system. The nutrient status of soils, harvested grain and pasture herbage were also measured along with the organic matter content and enzyme activities of the soils. Nutrient budgets (inputs minus outputs) for N, P and S on the conventional farms were generally balanced or positive so that the supply of these nutrients is unlikely to be limiting production. Nitrogen budgets were positive at all three alternative farms with biological N2 fixation accounting for most or all of the N input. One alternative farm had positive P and S budgets because of additions of compost, phosphate rock and elemental S. By contrast, at the other two alternative farms, net removal of P, and in one case S, occurred. In the other case, the S budget was balanced by one application (per rotation) of S fertilizer to the pasture. At these two sites, concentrations of grain N, P and S were lower than those at conventional sites and pasture herbage P and S concentrations were below recommended critical concentrations. Levels of total S and P and available P in soils were also lower on the alternative than conventional farms. Production on these alternative farms is relying on soil reserves of P and S, and additions of P and S will be required in the future to sustain current production levels. Organic C content and arylphosphatase, arylsulphatase and urease activities tended to be higher under alternative than conventional pastoral management. This was attributed to the longer pastoral phase under alternative (3–4 year) than conventional (1–2 year) management resulting in a small build up of organic matter. However, organic C content and enzyme activities were similar under conventional and alternative systems during the arable phase suggesting that conventional management had no adverse effect on soil biological activity.

The need for assessing sulphur (S) requirements in intensively-managed grassland ecosystems is becoming increasingly important because of the worldwide emphasis on sustaining non-renewable fertilizer resources and reducing atmospheric S emission. This paper reviews major factors affecting S cycling and efficient utilization of S fertilizers and soil S reserves in grazed grasslands. Models used for quantitatively describing S cycling in these ecosystems are also discussed. The review shows that most (95%) of the total soil S in intensively managed grazed grasslands is present as organic S and the remainder is in readily soluble and adsorbed S. Soil organic S that has been accumulated with time in grazed grasslands receiving regular S fertilizer applications can provide a significant amount of S for plant S nutrition. Carbon-bonded S is the major (50–85%) form of soil organic S, owing to the regular return of animal excreta and plant litter. Grazing animals have a major effect on the amount and rate of S cycling as most (87–90%) of S ingested by grazing animals is returned to soils as excreta. Excretal S is either recycled or subjected to leaching losses and transferred to stock camps. Leaching losses are expected to be higher in camp than in non-camp areas as camp soils contain higher soil organic and inorganic S fractions. Likewise more soil organic S is mineralized in camp than non-camp soils. This may provide S exceeding that taken up by plants and hence could lead to substantial S leaching losses in camp areas. This review identifies the lack of quantitative data on: (1) effects of soil microbial activity and plant S uptake on the fate of applied S fertilizers and excretal S in grazed grassland; (2) rates of soil S transformations as influenced by management and seasonal variables; (3) the contribution of soil organic S to plant S uptake and leaching losses in camp and non-camp areas of grazed grasslands. This scarcity of quantitative data is a major constraint in the development of dynamic S cycling models for predicting rates of S cycling and for estimating plant S requirements in grassland ecosystems where S cycling has not attained a steady state. When a steady state exists, mass-balance S models are more reliable than the traditional practice of using only soil or plant S tests for assessing long-term annual plant S rerequirements.

The paper presents study about the Product Service System, digital signal processing and IEC 61499 Standard. Product Service System talks about the importance of providing after sales service and some of its key concepts. Digital signal processing involves signal processing using various algorithms that can perform condition monitoring for oil and gas pipelines and IEC 61499 Standard is used to model these algorithms in to platform independent and easily configurable software.

The emerging technology of wireless sensor network (WSN) has changed the way people interact with the physical world. WSN produces myriad interdisciplinary research issues on information processing, control, communication and computation. It has also provided new paradigm for factory automation that has remarkable impacts on control, tracking, monitoring, and diagnostics of the manufacturing processes and equipments. This paper will provide a short survey on the research issues and implementation challenges coming with wireless networked control, distributed signal processing, condition-based maintenance and industrial efforts for standardization of communications, protocols and smart transducers.

This paper is based on a research effort aimed at developing a generic device interface and a protocol discovery methodology that can discover user-defined messages of an otherwise standard protocol. Our research focus is on the SEMI standard protocols used in communication between semiconductor manufacturing equipment and host stations for various purposes like recipe downloanding, status enquiry, and process monitoring through data retrieval. This paper describes an in-house developed methodology and framework for discovering user-defined messages from an "unknown" machine in order to rapidly set up communication with a host station based on existing knowledge, logic rules, and "deciphered" communication packets from host-initiated enquiries. This method allows an equipment builder to shorten the delivery time of a newly developed machine because it automates the communication configuration. The end-user benefits from our method because he can start integration of "unknown" equipment at a much earlier stage because of the automatic configuration of the communication middleware.

This paper presents an intelligent prediction and monitoring system for equipment failure prediction to support equipment maintenance, diagnostics and prognostics in manufacturing environment. The system architecture and implementation techniques, such as agent framework, real-time data acquisition and federated communication are briefly described. Details are given on the intelligent prediction engine which is the key component of the system. A case study for machining tool useful lifetime prediction is presented to demonstrate the usability of the system.

To develop advanced manufacturing systems and industrial automation equipment, a distributed control application platform (DCAP) is proposed (A. Aendenroomer et al., 2003). The DCAP can collect data from any device over heterogeneous networks, and control, monitor and optimize the operations of complex plants. Our discussions are focused on only two key components of the DCAP: how to manage heterogeneous devices and how to transmit data and commands among DCAPs. The background is introduced first. The methods employed to manage the heterogeneous devices and transmit commands and data are then discussed. An example is given to illustrate the schemes for designing and implementing a DCAP. Finally, a brief conclusion and future directions are given.

With the availability of powerful embedded CPU, it is possible to integrate multiple proprietary devices and field-buses into a system. This paper proposed the CDM (common device model) as a universal model for the devices and field-buses. With the universal interface of CDM, the system could manipulate the data from/to the devices in a universal way. CDM is composed of two parts: common device interface and device drivers. The novel model has been applied for robot control based on the distributed control application platform.

During the development of advanced manufacturing systems and industrial automation equipments, the developer has to consider a lot of Control Applications (CA). There are always growing need, for manufacturers to improve their capacity and flexibility to quickly respond to market requirements by designing novel CAs, modifying legacy ones and integrating them together. In the paper, Distributed Control Application Platform (DCAP) is presented as a control platform for developing CAs of advanced manufacturing systems. The DCAP can collect data over a heterogeneous control network from any device. The DCAP can then control, monitor and optimize the operations of the systems, whether for large and complex plants or for simple and single-user devices. The DCAP provides a software framework and tools to develop and deploy CAs for complex manufacturing systems. With the help of the DCAP, it is easy and fast to build complex control systems. A modular robot based manufacturing work cell system is adopted as a case study and the DCAP is used to develop CAs for the system.

This paper addresses various issues related to design and deployment of a Web-enabled distributed control application platform for industrial automation. The built-in Web functions enable programming and execution of remote control applications through a Web browser. New control applications can be created and existing control applications can be reconfigured and tuned on the fly. A case study is also described.

There is a trend among equipment builders to become more competitive by adding more and more features into their products. This process, which tremendously increases the complexity, is triggered by the aim to reach objectives like high reliability, speed and accuracy. In order to deal with this increasing complexity, SIMTech's manufacturing execution technology (MET) group has stated the objective to define methodologies and trajectories to describe and generate modules that can collaborate in a federated structure to become the archetype of tomorrow's equipment. In line with this, a research program has been started, which aims to deliver a platform for developing and deploying embedded control applications for a federated control environment. This platform is currently at the beginning stage of development, although a few key modules have already been completed or are close to completion, being a "communication broker" (ComBroker) and a "common device interface" (CDI). This paper focuses on the communication broker.

A prototype was developed of a generic platform which can be used for building reconfigurable distributed embedded controllers. The platform provides the tooling for assembling a component-based controller framework for distributed control and for generating Control Applications (CApps), which can run on such a controller and execute certain control functions. The Object Model was used for device drivers, as well as for non-mandatory components and implemented by respectively a Common Device Model (CDM) and a Component Management Model (CMM). By incorporating CDM and CMM into the framework's architecture it is possible to reconfigure the controller by plugging or unplugging components and drivers-remotely and on-the-fly-e.g. to cater for different hardware or to implement different control strategy. A case study, wherein a Distributed Control Application Platform was used to control a robot for production cell simulation, demonstrated the concept of remote configuration and control of applications developed with the platform.

This review reveals that crop residues of common cultivated crops are an important resource not only as a source of significant quantities of nutrients for crop production but also affecting soil physical, chemical, and biological functions and properties and water and soil quality. When crop residues are returned to the soils, their decomposition can have both positive and negative effects on crop production and the environment. Our aim as agricultural scientists is to increase the positive effects. This can only be achieved with the better understanding of residue, soil, and management factors and their interactions, which affect the decomposition and nutrient release processes. Data on nitrogen benefits and nitrogen recoveries from residues show that a considerable potential exists from residues, especially leguminous residues, not only in meeting the N demands of the succeeding crops, but also in increasing the long-term fertility of the soils. In addition, crop residues and their proper management affects the soil quality either directly or indirectly. Intensive cropping systems are very diverse and complex, so no one residue management system is superior under all situations. Ideally, crop residue management practices should be selected to enhance crop yields with a minimum adverse effect on the environment. It is suggested that in each cropping system, the constraints to production and sustainability should be identified and conceptualized to guide toward the best option. Multidisciplinary and integrated efforts by soil scientists, agronomists, ecologists, environmentalists, and economists are needed to design a system approach for the best choice of crop residue management system to enhance both agricultural productivity and sustainability.

Quaternary loess deposits containing charcoal and in situ organic matter constituents from Banks Peninsula, New Zealand, were subjected to various physical and chemical treatments before radiocarbon assay. A stepwide procedure was used in which each component was radiocarbon dated before and after the treatments were applied. The criterion adopted for judging the effectiveness of a treatment is an increase in the radiocarbon age of loess layer. On this basis the oldest and therefore the most reliable date was obtained from the intra-loess charcoal and its humic acid extract. By comparison, the radiocarbon ages of organic matter constituents of the whole or partitioned loess were much younger, and are considered to represent only average ages for the particular layers concerned. No advantage was gained by dating the carbon-enriched clay-humus fraction as opposed to whole loess samples. There is an apparent conflict between our dates and current interpretation of loess stratigraphy and chronology in the South Island of New Zealand, which requires further investigation. This uncertainty apart, the upper layers of multiple loess deposits are clearly much older than earlier reports indicate, and it follows that the correlation of these deposits with late-glacial events both within and beyond New Zealand is even more tenuous and unreliable than previously thought to be the case.

Six New Zealand topsoils of widely different origins and properties were subjected to 6m HC1 hydrolysis and the distribution of N fractions and amino acids were determined qualitatively and quantitatively. Of the total-N in the soils studied 83–91%, was hydrolysable with 6 m HCl. The largest proportion of the hydrolysable N was α-amino acid N (38– 42%). followed by hydrolysable-unknown N (HUN) (14–24%), and NH 4 + -N (14–22%). A significant proportion (25–50%) of the HUN fraction was accounted for by the non α-amino acid-N. Oxidative (3% H 2 O 2 ) hydrolysis released N-phenoxy amino acid-N and possibly N-compounds which were complexed with phenols and sugars. All soils had a similar amino-acid composition with a predominance of acidic amino-acids.

The effects of 5 different nitrogenous fertilisers (ammonium sulphate, ammonium sulphate + N-serve, potassium nitrate, poultry manure, and urea) each at 5 application rates (0, 150, 300, 450, or 600 kg N/ha) on the total nitrogen (N) and nitrate content of 2 varieties of spinach (Spinacea oleracea L.) and 1 variety of beetroot (Beta vulgaris L.) were evaluated in a pot experiment using Wakanui silt loam soil. The nitrification inhibitor, N-serve, was used to retard the microbial conversion of ammonium to nitrate. Total N and nitrate N generally increased with increasing rates of N applied. Potassium nitrate application resulted in the highest N uptake levels, and poultry manure application gave the lowest. N-serve depressed N uptake at 600 kg N/ha applied. Plants accumulated nitrate to a level potentially hazardous to health at only the highest rate (600 kg N/ha) of potassium nitrate, ammonium sulphate, and urea applied. Differences between the 2 varieties of spinach tested were not significant.

This review concerns the movement of foliar-applied substances through the leaf with an emphasis on plant nutrients. The movement of substances through the cuticle is well documented and is only outlined here. Knowledge of subsequent movement of substances throughout the leaf is rather sketchy. The various possible pathways of movement are outlined and discussed. Both symplastic and apoplastic movement seem possible. Ionic uptake and movement within leaves is complicated by photosynthesis which is occurring within many of the cells and by complex ionic movement associated with stomatal movement.

Humus samples derived from peat, moss or ornithogenic sources in the Antarctic continent have been examined by 13 C nuclear magnetic resonance techniques. The 13 C spectra show that the humus has undergone very little chemical modification. A fulvic acid fraction from a moss derived soil is almost entirely α- and β-glucose. The results also show that lignin is not a necessary precursor for aromatic components in soils. It is suggested that the aromaticity and carbohydrate content of certain soils is governed by the low temperature which influences the degree of humification.

Soil NH + 4 -N and NO − 3 -N at five soil depths (0–10, 10–20, 20–40, 40–60, 60–80 cm) and some environmental variables were measured in a field trial under fallow and wheat for 9 months. Significant linear and quadratic relationships were obtained relating soil NH + 4 -N, NO − 3 -N, NH + 4 -N + NO − 3 -N, and NH + 4 -N + NO − 3 + total-N uptake by wheat to soil heat accumulation (temperature), moisture, and rainfall. R 2 values generally decreased with soil depth and the maximum value (37%) was obtained for NO − 3 -N changes in the topsoil (0–10 cm). Although a considerable amount of variation in the inorganic values recorded is not included in the equations, our results suggest that the development of the above relationships particularly of the quadratic type are useful to predict crop requirements for N by measurement of environmental variables in the field.

The C 2 H 2 reduction (A.R.) assay was investigated for quantitative measurement of symbiotic N 2 fixation in established legume-based pastures under field conditions. It was found that the rate of C 2 H 4 production was relatively constant for approx 6 h. For an accurate estimation of the N 2 fixing activity, many field samples are required to overcome the errors due to the inherent spatial distribution of white clover ( Trifolium repens L.) within the pasture. Furthermore, it is necessary to physically integrate the day-to-day and diurnal variations in the N 2 fixing activity of the legume to obtain a reliable estimate of the rate of C 2 H 4 production and hence symbiotic N 2 fixation. The A.R. assay and an 15 N technique were compared for measuring symbiotic N 2 fixation in established pastures. A 3 h incubation in the A.R. assay gave the best estimate of symbiotic N 2 fixation relative to the 15 N technique. The 1 h incubation over-estimated and the 6 h incubation under-estimated the rate of symbiotic N 2 fixation.

Tephra samples from Whakatane Ash and Rotoma Ash in central North Island of New Zealand were subject to a wide range of chemical treatments in order to isolate different components of soil organic matter for radiocarbon dating. These samples were radiocarbon-dated before and after treatments and were then compared with radiocarbon dates derived from charcoal in the same tephra formation. Tephra deposits when dated as whole samples without prior chemical treatments, yielded unreliable radiocarbon dates. The reliability was improved by chemical treatments, particularly those involving acid hydrolysis with 6 M HCl or 72% H 2 SO 4 . Improvement, however, was less using the classical humus extraction and fractionation procedure.

The effect of Gigaspora margarita an endomycorrhiza—forming fungus, on the growth and chemical composition of perennial ryegrass plants grown at three concentrations and two sources of N were studied. The yield of plant tops was significantly depressed by mycorrhizal infection. Mycorrhizal plants had higher concentrations of free NH 4 + (and, consequently, higher cation excess concentrations), suggesting an impairment of protein synthesis possibly resulting from an inhibited supply of C. Total oxidizable C, soluble sugar content and C/N ratios were lower in mycorrhizal plants, suggesting that the mycorrhizal fungi were competing with the host for photosynthetically-derived C, consequently causing growth depressions. A possible mechanism of this competition is discussed.

The problem of harmonic penetration in power networks is of increasing importance. One method of estimating the penetration is to measure the harmonic voltages at points of common coupling and at selected locations in the network. This paper presents a method of solution which predicts harmonic penetration using a digital computer. The method of calculation is based upon the concept of conventional load flow. In conventional load flow only the fundamental frequency component of the voltage is calculated. In the proposed method this can be extended to any desired frequency range and these voltages at different frequencies are calculated simultaneously. The major obstacles to such an approach would be the establishing of a mathematical model and valid assumptions to ensure consistent convergence. The proposed method overcomes both of these obstacles. The method had been tried on a sample network with different starting points and with different loading conditions, and consistent convergence was obtained.

Selected horizons of three present-day New Zealand soils and paleosols underlying them were studied, using standard soil chemical and mineralogical methods of the New Zealand Soil Bureau and a sensitive amino acid method. The chemical and mineralogical data obtained contributed little to the recognition of buried soils. Amino acid-nitrogen levels, on the other hand, showed significant differences between the various soil horizons. In all cases, they decreased with depth, except that whenever a paleosol occurred there was a definite and significant increase with respect to that present in the overlying horizon. Differences in amino acid levels between horizons were found to be valuable as indicators for the presence of paleosols that have been identified in the field. In addition, they confirmed the pedological differentiations of buried soil horizons.

Humic and fulvic acids from several sources were separated into three spectral types depending upon their infrared absorption characteristics. Those belonging to Type I showed equally strong bands at 1720 and 1600 cm−1, with no discernible absorption being evident at 1640 cm−1. A distinguishing characteristic of the preparations giving spectra of Type II was a very strong 1720 cm−1 band, a shoulder at 1650 cm−1, and the absence of a 1600 cm−1 band. The preparations of Type III showed pronounced bands indicative of proteins and carbohydrates. Observed spectral changes in the 1700-1600 cm−1 region indicated that the humification process consisted, in part, of a loss of COOH groups and a change in the environment of CO from the free or weakly H-bonded state to strongly chelated forms.

Concern has been expressed (Rasmussen er nl., 1976; Crutzen and Ehhalt, 1977; Bremner and Blackmer, 1978; Cicerone et al., 1978) about possible detrimental effects to the earth’s ozonosphere due to a suggested increase in tropospheric N,O. This increase could result from the expanding use of artificially-manufactured nitrogenous fertilizers. In pastoral agriculture in a number of countries (e.g. New Zealand and Australia) high concentrations of N are constantly being voided as urine on pastures by grazing animals. This may present a situation for NzO production and release to the atmosphere. Whereas artificial fertilizers are normally applied by broadcasting or banding, sheep and cattle urine is voided in discrete patches in which the concentration of applied N frequently exceeds the equivalent of 1000 kg haa’ (Doak, 1952; Barlow, 1974). Under these conditions soil pH increases and high concentrations of NOT-N can accumulate. Such effects may give rise to chemodenitrification routes for subsequent NzO release (Nelson and Bremner, 1970). Nitrous oxide fluxes from urine patches in grazed pastures have not been studied extensively, mainly because of the difficulty in measuring the very small amounts of N20 released in air samples. Using the highly sensitive electroncapture gas chromatograph method (Rasmussen et al., 1976) we report long-term release rates of N,O from nitrogenous fertilizers and sheep urine applied to grazed pasture blocks and short-term release rates from laboratory incubation of pasture soils. Our results demonstrate a positive stimulation of initial N,O release when sheep urine was applied to the soil compared with similar applications of ammonium sulphate and urea. An established ryegrass (Lolium perenne L.) white clover (Trifolium repens L.) grazed pasture in the Lincoln College Sheep Stud Farm was used. The soil is a Templeton silt loam (Cox et ul., 1971) a Dystric Ustochrept. It has the following properties: pH (1: 2.5 water) = 6.2, total N =0.31x, NOT-N = 26 peg gg’, NH:-N = 45 fig g’, organic C = 4.2%, field capacity = 34%. Eight blocks (165 x I65 x 150 mm) of soil complete with undisturbed pasture herbage were cut from the site and fitted into 5 1 polypropylene containers. These were transferred to a laboratory window-box and maintained there under ambient lighting and temperature conditions (20°C) for 45 days. During this period watering (to 32% average moisture capacity-see Fig. 1) was carried out. All pasture blocks except the controls received on each of 3 occasions 0.5 g N as either ammonium sulphate, urea or sheep urine in lOOmI of water: equivalent approximately to 200kgNhaa’, giving a total application of about 600 kgN ha-‘. Control pasture blocks received 100 ml of distilled water. Duplicates of each treatment were used. The sheep urine was collected from cannulated Romney ewes, analysed for pH (7.1) total N (1.37 g lOOmI-‘) and urea-N (1.26 g 100 ml-‘) and stored frozen till required. Subsequent analysis upon thawing showed no chemical changes associated with these N fractions. Nitrous oxide fluxes were measured using an intermittent enclosure technique in which air-tight lids were fitted to the polypropylene containers and the released N,O allowed to accumulate in the enclosed headspace (approx. 1 1). The lid was closed for about 1 h, during which time at least 2 air samples (I ml) were removed using a gas-sampling valve (Carle 8 port) and analysed for N,O. The analytical system consisted of a Varian 2800 gas chromatograph fitted with a 3 m x 3 mm O.D. stainless steel column of Porapak Q maintained at 20°C. This was connected to a PyeUnicam linearized pulsed electron-capture detector maintained at 35OC. The carrier gas was O,-free Nz at a Bow rate of 50 ml min’. Adequate separation of NzO from the potentially interfering gas CO, was achieved (Cicerone et al., 1978): their retention times being 195 s and 242 s respectively. The primary standard calibration gas was a 104 ~1 NzO 1-l in N2 gas mix (Matheson, U.S.A.). Secondary NzO-air standards were prepared by diluting known volumes of the primary standard gas with known volumes of compressed air. N,O peak areas were calculated automatically on a Varian Aerograph Model 408 integrator. To study initial N,O release rates under non-saturated soil aerobic conditions, small scale incubations were performed. Samples of air-dry soil (10 g

Some statements referring to our work on 13 C NMR of humic and fulvic acids have been recently reported in this journal by Ruggiero and co-workers. They are discussed in order to avoid possible misinterpretations.