The relationship between water intake rates,paddy ponding depth,and farmers’ water management techniques

Japanese farmers manage their irrigation water based on their past experiences and preferences, considering such factors as weather and available water (hereafter defined as content/h609g2laj0jydd1a/xxlarge8220.gif" alt="ldquo" align="MIDDLE" BORDER="0">empirical water managementcontent/h609g2laj0jydd1a/xxlarge8221.gif" alt="rdquo" align="MIDDLE" BORDER="0">). They elaborately control the intake and drainage rates of their own paddy fields to maintain optimal ponding depths. But these well-managed systems will drastically change because of the decreasing number of farmers. Therefore, it is necessary to clarify if the optimal ponding depth will be maintained within the limits of traditionally-allowed water intake rate from the main river. The first objective of this study was the quantification of actual water use in the paddy fields, resulting from the farmerscontent/h609g2laj0jydd1a/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> water management on the basis of their experience. The significance of the present water intake rate under empirical water management was studied for a paddy field command area of about 230 ha. Water intake rates and the water requirements of the whole area were investigated by measuring the flow rate at 17 points of irrigation and drainage canals. Characteristics of the farmerscontent/h609g2laj0jydd1a/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> empirical water management were investigated by measuring the hourly changes in inflow and outflow rates for a sub-area using an automatic measurement system, and an inferential method of determining water management patterns for the paddy fields was proposed. The newly-proposed inferential method was introduced in the tank model, which expresses the characteristics of water management in the command area. The Shuffled Complex Evolution Algorithm (SCE-UA) method was used for optimizing the model parameters. It was proven that the model accuracy improved when the farmerscontent/h609g2laj0jydd1a/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> empirical water management was taken into account. The optimal amount of water to be applied to the command area was quantified by the simulation. The second objective was to predict the effect of the decreasing number of farmers on future water use conditions. The simulated result indicates the difficulty of maintaining optimal ponding depth for the whole command area when the farmerscontent/h609g2laj0jydd1a/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> empirical water management is not maintained. In other words, results indicated that efficient water use requires an automatic water management system or a new pipeline system to replace the farmerscontent/h609g2laj0jydd1a/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> present empirical water management.     

Decomposition and phosphorus release from organic residues as affected by residue quality and added inorganic phosphorus

The combined use of organic residue and inorganic fertiliser-phosphorus (P) is appropriate in meeting both the short and long-term P requirement of crops. To assess the influence of added inorganic fertiliser-P on the processes of decomposition and P release from the residue and the relationships with quality, prunings of Gliricidia sepium, Leucaena leucocephela, Senna siamea, Acacia mangium and Paraserienthus falcataria were incubated without and with added inorganic fertiliser-P for 56 days. Soil was added only as inoculum. Decomposition rate and amounts of acid extractable-P (P release) were in the same order: G. sepium >S. siamea > L. leucocephela >P. falcataria > A. mangium. Unlike the other residues, A. mangium released no P despite the loss of half its mass during the 8 weeks of incubation. The residue P content correlated with P release. However, decomposition rate did not correlate with residue P content but with the lignin, polyphenol and cellulose content, and ratios to P. These ratios were negatively correlated with P release suggesting that lignin and polyphenol contents influence P release more when the residue-P content is low. Results suggest that rate of decomposition influences the release of P. The critical residue P content for P release was estimated to be 0.12% < P < 0.19%. Added P had no effect on decomposition and P release from the residues.     

Dimensional instability of cement bonded particleboard

This paper examines the dimensional instability of cement bonded particleboard (CBPB) and discusses the behaviour of CBPB during cyclic changes in relative humidities (RH). The results indicated that the changes of CBPB in both mass and dimensions reflected the changes in RH; in a cycle 90–65–35–65–90%RH the change of per percentage change in RH was 1.0:1.3:1.3:2.5 for mass, 1:2:2:1 for length and 1.3:1.1:1.0:1.0 for thickness. The changes were closely related to the structure of CBPB and the nature of the cement paste and wood chips. Thickness change was double that of the length change between 65 and 35%RH and triple that between 65 and 90%RH. The rate of change in mass was much higher than that in dimensions. The hysteresis loops were dissimilar to those of other wood and wood-based materials, with the loops of mass change closed between 65 and 90%RH, while the loops for dimensional changes were open. A set of the former loops moved upward and the latter moved downward with increasing number of cycles, corresponding to an accumulated increase in mass, but decrease in dimensions. The models developed for CBPB under constant and a single changing RH were successfully applied to changes under cyclic RH.The sorption behaviour and dimensional movement of CBPB has been shown to be influenced not only by RH, but also by its intermediate history, with the maximum values for change within every phase of sorption, in both mass and dimensions, being higher for the cycling between 35–90%RH than the cycling regime 35–65–90%RH. The ratios of dimensional changes to mass change of CBPB were greater under the latter regime than under the former regime.The senior author wishes to thank Professor W.B. Banks of University of Wales, Bangor for his constructive discussions and assistance and the British Council for partly financial support.     

Image analysis and bending properties of model OSB panels as a function of strand distribution,shape and size

The technique of image analysis has been used to assess the quality of model oriented strand board panels by investigating the relationships between shape and size of strands, the distribution of strands and bending properties. A batch of commercial strands was analysed by image analysis and the distribution of the shape and size of strands was quantified. The strands were categorised into five strand types as a function of size and aspect ratio. In general, strand shapes were observed to be mostly rectangular and there was also a wide variation in strand dimensions in commercial material. Bigger area strands had low aspect ratios and small strands had high aspect ratios. Half of the commercial strands were longer than 100 mm.Model OSB panels were manufactured in the laboratory by hot pressing strand mats formed from each of the five strand types. Strands were laid up by hand into the forming mat and following pressing the orientation and shape of strands was evaluated by image analysis and the panels were tested in a three point bending. Large area (type 3) strands with high aspect ratios produced model panels with optimum strand orientation and mechanical properties.Type 3 panels were also fabricated from strands dropped through a slotted forming device in order to simulate the delivery of strands to the forming line under factory conditions. As the height of strand delivery increased from 0 to 100 to 200 mm the disorientation of strands in the pressed panels progressively increased and as a result mechanical properties in bending were reduced.Image analysis is therefore a powerful tool for evaluating the distribution of commercial strand shapes and the relationship between strand geometry, strand orientation and the mechanical properties of oriented strand board.     

Effects-based Assays in the Earthworm Aporrectodea caliginosa: Their Utilisation for Evaluation of Contaminated Sites before and after Remediation (8 pp)

Goal, Scope and Background   In a preliminary ecological risk assessment, potential adverse effects of contaminants are often evaluated by measuring chemical residues and comparing these with regulatory guidelines. However limitations with this approach with regards to establishing actual effects have resulted in the increasing usage of sublethal effects-based assays, including biomarkers, to evaluate the hazard posed by contaminants in the environment. In this study a number of effects-based endpoints in the earthworm Aporrectodea caliginosa were evaluated to determine their comparative sensitivity for assessment of adverse effects of soil contaminated with petroleum hydrocarbons. Methods   Adult and juvenile earthworms were exposed for 4 weeks to sublethal concentrations of soil collected before and after remediation of a petroleum-contaminated site. A suite of endpoints were measured in these earthworms, including mortality, fecundity, growth, and juvenile maturation, and two less traditional endpoints, the biomarker, the neutral red retention assay (NRRA) and an avoidance behaviour test. Results and Discussion   Cocoon viability in this species is not a reliable parameter to measure, due to low viability in controls and a high coefficient of variation. Growth in adult earthworms was a more sensitive parameter than cocoon production. Maturation and growth of juveniles have been proposed as more sensitive endpoints than adult cocoon production and growth respectively. This was not apparent in the growth parameters, but maturation of juveniles did appear to be more sensitive than cocoon production by adults. The NRRA was a more sensitive parameter than cocoon production, and the NRRA and growth were both affected at the lowest concentration tested. The NRRA response appeared to be more sensitive than growth, but NRRT was only evaluated in one soil only, while the other parameters were assessed in two soils. However, the NRRA has previously been found to be more sensitive than growth after exposure to a number of contaminants. The avoidance behaviour assay exhibited similar sensitivity to growth and fecundity and could therefore be useful as a simple pre-screening test. Conclusion   The chronic endpoints, growth, cocoon production, and juvenile maturation parameters, were all sensitive endpoints for detecting exposure to the petroleum-hydrocarbon-contaminated soil. The NRRA was the most sensitive of the endpoints assessed and could be used as an early-warning indicator to predict adverse impacts. Avoidance behaviour could be used as a simple pre-screening test to evaluate contaminated soils prior to more extensive and invasive testing. Recommendations and Perspective   Measuring chemical concentrations in environmental samples is not always useful, as the toxicological impacts of exposure to these concentrations are not always discernible. However, the use of effects-based endpoints, either in situ or in the laboratory using laboratory-reared earthworms, can account for the bioavailability of chemicals in the soil, and can therefore provide information on the toxicological impacts of exposure. The assays tested in this research were sensitive indicators of exposure, and therefore can be used to determine potential ecological risks at contaminated sites and to monitor the progress of remediation at these sites.     

Statistical methods helping and hindering environmental science and management

Environmental scientists face the reality that many of their journals’ editors and referees routinely insist that results be accompanied by statements of statistical significance, obtained from two-sided tests of point-null hypotheses. Many in these three groups of people appear only vaguely a ware of the arbitrarinessoften invoked by this procedure and of the information sterility in a single p-value. The interpretation to be made of the failure of a test to attain such significance is not clear. For such reasons, some colleagues (and senior statisticans) have called current usage of the procedures into serious question. Some reasons for this dislocation and some of the more dramatic consequences for environmental science and management are presented. Interval and Bayesian approaches can offer remedies.     

Phenotypic and QTL analyses of herbage production-related traits in perennial ryegrass (<Emphasis Type="Italic">Lolium perenne</Emphasis> L.)

Phenotypic and genetic evaluation of morphological traits associated with herbage biomass production was undertaken in a perennial ryegrass (Lolium perenne L.) biparental F₁ mapping population (n = 200) with parent plants from cultivars ‘Grasslands Impact’ and ‘Grasslands Samson’. Morphological traits measured on three clonal replicates of the parental genotypes and 200 F₁ progeny in a glasshouse in two separate trials (autumn and spring) included: dry weight (DW), leaf elongation rate (LER), initial tiller number (TNs), final tiller number (TNe), site filling (Fs), tiller weight (TW), leaf lamina length, leaf tip and ligule appearance rates (ALf, ALg) and leaf elongation duration (LED). Principal component analysis of patterns of trait association identified negative correlation between TNs or TNe, and TW as the primary basis for morphological difference and indicated that either high LER or long LED could reduce TN. Plants with higher LER tended to have increased DW. Quantitative trait loci (QTL) were detected on all seven linkage groups (LG) of a perennial ryegrass linkage map for all but three traits. A total of 61 QTL were identified, many of which clustered at 15 shared genome locations. Significant genotype by environment effects were encountered, evidenced both by variation between experiments in genotype rankings and by a general lack of commonality for QTL for the same traits in the different experiments. Only five QTL, for ALf, ALg and TN, were conserved between autumn and spring trials. A QTL for TN and DW on LG6 is a strong candidate for application of MAS in future plant improvement work and was found to be co-linear with QTL for equivalent traits reported on chromosome 2 in rice.     

Influence of Storage Environment,Surface Coating,and Individual Shrink Wrapping on Quality Assurance of Guava (<Emphasis Type="Italic">Psidium guajava</Emphasis>) Fruits

Guava (Psidium guajava) fruits of cv. L-49 with individual shrink wrapping using 9 content/r1m16070058xw671/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0"> LLDPE film could be successfully stored up to 12 days at ambient and 18 days in evaporative cool chamber with negligible loss in vitamin C content. The untreated fruits lose 25–30% of ascorbic acid within 1week after harvest. Delay in senescence and metabolic activities as supported by less changes in soluble solids, sugars, acidity, respiration, and ethylene evaluation rate was also observed in individual shrink wrapped fruits in cool chamber. The spoilage of fruits by Fusarium rots was significantly less in cool chamber in individually shrink wrapped fruits followed by Sta-fresh treatment. Sta-fresh was more effective in cool chamber than ambient. Individually stored wrapped fruits scored a better value of sensory score than Sta-fresh under both the storage condition.     

Dimensional instability of cement bonded particleboard: Modelling CBPB as a composite of two materials

Previous papers have quantitatively indicated that the total movement of cement bonded particleboard (CBPB) is equal to the sum of the movement of its components. This paper examined the efficacy of the law of mixtures when applied to the movement of a wood-cement composite under internal swelling or shrinkage stresses. Abundant data generated in companion papers were first manipulated to develop the universal formulae for predicting the movement of components. In conjunction with previous numerical results from image analysis of the structure of CBPB, and the orientated elasticity and stress algorithms, the models for theoretically predicting mass and dimensional changes of CBPB were derived. Validation studies were conducted and these demonstrated an excellent agreement of the theoretical predictions with experimental data for both mass and dimensional changes of CBPB due to internal swelling or shrinkage stresses during adsorption and desorption. The success also implied that CBPB can be treated as a composite and its properties can be well derived by the law of mixtures even though CBPB is an unusual type of composite having a very high volume fraction of wood chips, but a very high mass fraction of cement paste.Notation E_RT Mean transverse modulus of elasticity of wood - E_L Longitudinal modulus of elasticity of wood - E_p Modulus of elasticity of cement paste - E_wa Modulus of elasticity of embedded wood chips at content/6184c1dx293tugje/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> angle - E_{content/6184c1dx293tugje/xxlarge952.gif" alt="theta" align="BASELINE" BORDER="0">} Modulus of elasticity of wood chips at content/6184c1dx293tugje/xxlarge952.gif" alt="theta" align="BASELINE" BORDER="0"> direction - E_{content/6184c1dx293tugje/xxlarge981.gif" alt="phiv" align="MIDDLE" BORDER="0">} Modulus of elasticity of wood chips at content/6184c1dx293tugje/xxlarge981.gif" alt="phiv" align="MIDDLE" BORDER="0"> direction - G_LRT Mean transverse shear modulus of wood - content/6184c1dx293tugje/xxlarge916.gif" alt="Delta" align="BASELINE" BORDER="0">L(T)_{cpcontent/6184c1dx293tugje/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">} Length/width (thickness) change of CBPB at content/6184c1dx293tugje/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> angle - content/6184c1dx293tugje/xxlarge916.gif" alt="Delta" align="BASELINE" BORDER="0">L(T)_p Length (thickness) change of cement paste - m_pf Mass fraction of cement paste in unit mass of CBPB - m_wf Mass fraction of wood chips in unit mass of CBPB - content/6184c1dx293tugje/xxlarge916.gif" alt="Delta" align="BASELINE" BORDER="0">M_cpj Mass change of CBPB at the various conditions tested - content/6184c1dx293tugje/xxlarge916.gif" alt="Delta" align="BASELINE" BORDER="0">M_pj Mass change of cement paste at corresponding conditions - content/6184c1dx293tugje/xxlarge916.gif" alt="Delta" align="BASELINE" BORDER="0">M_wj Mass change of wood chips at corresponding conditions - content/6184c1dx293tugje/xxlarge916.gif" alt="Delta" align="BASELINE" BORDER="0">M(L; T)_w/P Mass, length or thickness changes of wood chips or cement paste at various conditions - t Duration of exposure - content/6184c1dx293tugje/xxlarge957.gif" alt="ngr" align="BASELINE" BORDER="0">_LRT Mean transverse Poissoncontent/6184c1dx293tugje/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">s ratio of wood - V_pf Volume fraction of cement paste in unit mass of CBPB - V_wf Volume fraction of wood chip in unit mass of CBPB - content/6184c1dx293tugje/xxlarge961.gif" alt="rgr" align="MIDDLE" BORDER="0">_cp Density of CBPB - content/6184c1dx293tugje/xxlarge961.gif" alt="rgr" align="MIDDLE" BORDER="0">_k Density of wood chip or cement paste - content/6184c1dx293tugje/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">_{cpcontent/6184c1dx293tugje/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">} Overall stresses of CBPB at content/6184c1dx293tugje/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> angle - content/6184c1dx293tugje/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">_L Stress in the longitudinal direction of wood - content/6184c1dx293tugje/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">_RT Mean stress in the transverse direction of wood - content/6184c1dx293tugje/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">_p Stress of cement paste - content/6184c1dx293tugje/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">_{wcontent/6184c1dx293tugje/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">} Stress of the wood chips at content/6184c1dx293tugje/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> angle - content/6184c1dx293tugje/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">_{content/6184c1dx293tugje/xxlarge952.gif" alt="theta" align="BASELINE" BORDER="0">} Stress of the wood chips at content/6184c1dx293tugje/xxlarge952.gif" alt="theta" align="BASELINE" BORDER="0"> direction - content/6184c1dx293tugje/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">_{content/6184c1dx293tugje/xxlarge981.gif" alt="phiv" align="MIDDLE" BORDER="0">} Stress of the chip at content/6184c1dx293tugje/xxlarge981.gif" alt="phiv" align="MIDDLE" BORDER="0"> direction - content/6184c1dx293tugje/xxlarge949.gif" alt="epsi" align="BASELINE" BORDER="0">_{cpcontent/6184c1dx293tugje/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">} Strain in CBPB - content/6184c1dx293tugje/xxlarge949.gif" alt="epsi" align="BASELINE" BORDER="0">_p Strain of cement paste - content/6184c1dx293tugje/xxlarge949.gif" alt="epsi" align="BASELINE" BORDER="0">_WL Strain in the length of wood chips - content/6184c1dx293tugje/xxlarge949.gif" alt="epsi" align="BASELINE" BORDER="0">_WT Strain in the thickness of wood chips - content/6184c1dx293tugje/xxlarge949.gif" alt="epsi" align="BASELINE" BORDER="0">_{wcontent/6184c1dx293tugje/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">} Strain in wood chips - content/6184c1dx293tugje/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> Angle between the longitudinal direction of wood chips and surfaces or edges of CBPB - content/6184c1dx293tugje/xxlarge952.gif" alt="theta" align="BASELINE" BORDER="0"> Angle between wood chips and edges (length direction) of CBPB - content/6184c1dx293tugje/xxlarge981.gif" alt="phiv" align="MIDDLE" BORDER="0"> Angle between wood chip and vertical coordinate - A, B, C Coefficients related to the feature of materials and exposure conditions The senior author wishes to thank Professor W.B. Banks of University of Wales, Bangor for his constructive discussions and assistance and the British Council for partly financial support.