Persistence and colonization of gaps in sown swards of grass and clover under different sward managements

The effects of extensive sward management and patch size on the persistence and colonization of gaps in sown swards was examined by creating gaps of five different sizes (2·3, 7, 10, 14 and 19 cm in diameter) in four different sward treatments: a fertilized sward grazed to 4 cm, i.e. relatively intensive management, and three extensively managed unfertilized swards, which were not grazed or grazed to 4 cm or 8 cm. The swards were originally sown with ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), but had developed differences in species composition as a result of the management treatments imposed 2 years before and during the experiment. Light quality measurements, i.e. red-far red (R/FR) ratio, were used to determine when the light environment in the gaps no longer differed from that in control, uncut patches and this was used as an estimate of gap persistence. Persistence of gaps depended on both sward management and gap size. Gaps disappeared most rapidly in the ungrazed sward and fertilized 4-cm sward, and most slowly in the unfertilized 8-cm sward. Small gaps persisted for up to 2 weeks in all but 8-cm swards, whereas larger gaps were estimated to persist for up to 20–25 weeks in unfertilized, grazed swards. There was no evidence that the number of grass or dicotyledonous species increased in the gaps compared with the control areas. There were significant positive linear relationships between the vegetation that developed in gaps and that in the control, uncut patches, reflecting the different species composition of the established sward of the grazed (grass-dominant) and ungrazed (Ranunculus repens-dominant) treatments. For total grass dry matter and tiller numbers, as well as L. perenne tiller numbers, there was a small, but significant, effect of both patch size and sward management on the slopes of the regressions between the controls and gaps. The results are discussed in relation to the potential for species composition of sown swards to change as a result of gap creation.     

Effect of clothing constructions on core temperature during exercise and recovery at an ambient temperature

In this paper we investigated the human thermoregulatory responses, especially core temperature behavior during exercise and recovery at ambient temperature of 10 °C and 50 % R.H. under the conditions of wearing three kinds of clothing with same weight and different constructions. Six healthy men wore three kinds of clothing: one insulating the upper half of the body thinly and the lower half of the body heavily (clothing A, the weights in the upper and lower halves of the body were 489 g and 1278 g, respectively.), the second one insulating the upper half of the body heavily and the lower half of the body thinly (clothing B, 1212 g and 559 g, respectively.), and the third one insulating the upper and lower halves of the body moderately (clothing C, 899 g and 879 g, respectively.). The level of rectal temperature was the greatest during exercise in clothing C and the lowest during recovery in clothing A. The increasing and decreasing rates of core temperature during exercise and recovery, respectively, were the smallest in clothing B. These findings are discussed in terms of different cooling efficiency from the lower extremities and disfunction of counter current heat exchange system among clothing A, B, and C.     

Physicochemical control of durum wheat grain filling and glutenin polymer assembly under different temperature regimes

Durum wheat is grown in the Mediterranean area where drought and high temperature frequently prevail and impact grain texture, composition and yield. The purpose of this work was to examine the effect of high temperature on grain development and final composition according to the timing of exposure. High temperature (up to 27.5 °C) was applied either during the linear grain filling or drying phases or during whole grain development. The dynamics of grain dry mass, water, glutenin polymers, and protein bodies during grain development were determined. Irrespective of high temperature timing, the arrest of grain filling was observed at 45.9% grain moisture content. At that point, starch granules included in endosperm cells reached their physical packing limit, limiting further deposits. HT applied before physiological maturity shortened the duration of grain filling and resulted in a significant increase in grain protein concentration and in the proportion of vitreous grain. Late formation of sodium dodecyl sulfate (SDS)-insoluble glutenin polymers below 32% grain moisture content was also favored. The ability of wheat storage protein to form a viscoelastic matrix embedding starch granules at the beginning of grain desiccation is proposed to be mandatory for gaining vitreous grains and a high proportion of SDS-insoluble glutenin polymers.     

The effect of temperature and water on the mechanical properties of wool fibres investigated with different experimental methods

The tensile and durability properties of single wool fibres were investigated with tensile testing method and lever equipment giving the results examined by Zhurkov’s kinetic equation under the effects of temperatures and water. Moreover, Differential Scanning Calorimetry (DSC) method was applied to determine denaturation and degradation peaks and corresponding enthalpies of wool fibre. It was shown that with increasing temperature, tensile properties and durability of the wool fibres decreased considerably. A great decrease on tensile properties was seen at temperatures higher than ∼200 °C after which a denaturation doublet of α-keratin and a wide thermal degradation peak were observed in DSC diagrams. Moreover, the wet fibres obtained lower tensile characteristics except breaking extension which increased by 9 % and 20 % for the fibres kept in water for one h and one month, respectively. However, the breaking extension of the fibre tested in water increased greatly by 73 % which indicates the important role of water molecules on the intermolecular interactions during stretching. The weakening effect of water molecules on the structure was also shown by DSC result of wet wool fibres at which the thermal degradation enthalpy of α-keratin and other histological components decreased by 22 %. The changes of the tensile and durability characteristics of wool fibres were compared and discussed in detail based on Zhurkov’s equation and intermolecular interactions.     

Modelling net photosynthetic rate of field-grown cocksfoot leaves under different nitrogen, water and temperature regimes

A simple multiplicative model using temperature, foliage nitrogen (N) concentration and water status was developed to predict the maximum photosynthetic rate (Pmax) of field‐grown cocksfoot (Dactylis glomerata L.) leaves when none, one, two or all the factors were limiting. The highest Pmax was 27·4 μmol CO₂ m^–2 s^?1 in non‐limited conditions, which was defined as the standardized Pmax value dimensionless (Pmax_s=1). Pmax_s increased 0·058 units per °C from 10°C to the optimum range (19–23°C) (Pmax_s=1) and then declined 0·077 units of Pmax_s per °C from 23 to 31°C. Pmax_s=1 was also measured from 59 to 52 g N kg^?1 dry matter (DM) foliage N. Pmax_s then decreased at the rate of 0·115 units per 10 g N kg^?1 DM from 52 to 26 g N kg^?1 DM, and 0·409 units of Pmax_s per 10 g N kg^?1 DM from 26 to 15 g N kg^?1 DM. For predawn leaf water potential (ψ_lp), Pmax_s=1 was measured from ?0·1 to ?1·2 bar but declined linearly at a rate of 0·078 units per bar of ψ_lp from ?1·2 to ?14·0 bar because of a linear decrease in stomatal conductance. An interaction between low N content (≤20 g N kg^?1 DM) and high temperature (>23°C) was also detected. Together, this multiplicative model accounted for 0·82 of the variation in Pmax_s.     

Effects of elevated CO2 concentration on growth and photosynthesis of Chinese yam under different temperature regimes

Chinese yam (‘yam’) was grown at different carbon dioxide concentrations ([CO₂]), namely, ambient and elevated (ambient + 200 μmol mol^?1), under low- and high-temperature regimes in summer and autumn, separately. For comparison, rice was also grown under these conditions. Mean air temperatures in the low- and high-temperatures were respectively 24.1 and 29.1 °C in summer experiment and 20.2 and 24.9 °C in autumn experiment. In summer experiment, yam vine length, leaf area, leaf dry weight (DW), and total DW were significantly higher under elevated [CO₂] than ambient [CO₂] in both temperature regimes. Additionally, number of leaves, vine DW, and root DW were significantly higher under elevated [CO₂] than under ambient [CO₂] in the low-temperature regime. In autumn experiment, tuber DW was significantly higher under elevated [CO₂] than under ambient [CO₂] in the high-temperature regime. These results demonstrate that yam shows positive growth responses to elevated [CO₂]. Analysis of variance revealed that significant effect of [CO₂] × air temperature interaction on yam total DW was not detected. Elevated-to-ambient [CO₂] ratios of all growth parameters in summer experiment were higher in yam than in rice. The results suggest that the contribution of elevated [CO₂] is higher in yam than in rice under summer. Yam net photosynthetic rate was significantly higher under elevated [CO₂] than under ambient [CO₂] in both temperature regimes in summer. Elevated [CO₂] significantly affected on the rate in yam but not in rice in both experiments. These findings indicate that photosynthesis responds more readily to elevated [CO₂] in yam than in rice.     

Prediction of air filter efficiency and pressure drop in air filtration media using a stochastic simulation

In this paper, we discussed the relationship of filter efficiency and pressure drop with the porosity, fiber diameter and filter thickness by Geodict®. We found that filter efficiency has exponential relationship with filter porosity, fiber diameter and thickness. Furthermorethe pressure drop has a linear relationship with filter thickness and exponential relationship with filter porosity and fiber diameter, respectively. The influence of electrostatic charge on the particle deposition has been investigated. Simulation results were compared with the actual test results by TSI 3160.     

Effects of elevated CO2 concentration on bulbil germination and early seedling growth in Chinese yam under different air temperatures

The present study investigated the effects of elevated carbon dioxide concentration ([CO₂]) and air temperature on the germination of seed bulbils and the seedling vigour of two Chinese yam lines. Plants were grown under two [CO₂] levels, ambient and elevated (ambient + 200 μmol mol^?1), and two mean air temperature regimes, 22.2 °C (ambient + 1.4 °C) and 25.6 °C (ambient + 5.2 °C). Elevated [CO₂] did not affect bulbil germination under both air temperature regimes. During the early growth stage, the dry weight (DW) of leaves, vines, shoots, roots, belowground parts (roots + tubers) and whole plants were higher under elevated [CO₂] than ambient [CO₂] for both lines under the low- and high-temperature regimes. The values of vigour indexes (index I = germination % × seedling length and index II = germination % × seedling DW) were also higher under elevated [CO₂] than ambient [CO₂] for both lines. These results indicated that Chinese yam seedlings respond positively to elevated [CO₂] during the early growth stage. The above:belowground DW ratios were lower under elevated [CO₂] than ambient [CO₂] in seedlings with very small new tubers for both yam lines, indicating that elevated [CO₂] strongly affected the root growth in the early growth stage. The DWs of post-treatment seed bulbils were higher in the elevated [CO₂] under both air temperature regimes. The results showed that Chinese yam used a smaller amount of the reserves in seed bulbils under elevated [CO₂] than under ambient [CO₂].     

Improving maize growth and development simulation by integrating temperature compensatory effect under plastic film mulching into the AquaCrop model

Temperature compensatory effect, which quantifies the increase in cumulative air temperature from soil temperature increase caused by mulching, provides an effective method for incorporating soil temperature into crop models. In this study, compensated temperature was integrated into the AquaCrop model to investigate the capability of the compensatory effect to improve assessment of the promotion of maize growth and development by plastic film mulching(PM). A three-year experiment was conducted ...     

Modelling and experimental studies of air permeability of nonuniform nonwoven fibrous porous media

The fibrous porous materials stand out as a unique class of porous media. The air permeability of these media is very important for a wide variety of medical and technical applications. It is observed that the air permeability of these media is different at different locations owing to the nonuniformity in fibre packing density. This observation is taken into consideration while developing an analytical model of air permeability of nonuniform fibrous porous media. This model is reported in this article and demonstrated with the help of practical examples of real nonwoven fibrous porous materials. The theoretical results are found to be in satisfactory agreement with the experimental ones.     

A new experimental study of influence of fabric permeability, clothing sizes, openings and wind on regional ventilation rates

In this study, a local ventilation rates (VR) measuring system based on stead-state method was developed. This system can measure the local VR of the right arm, the left arm, the chest and the back locations of the upper body garment simultaneously. The whole clothing VR can also be computed. To study the influence of fabric permeability, clothing sizes, hem opening, and wind on local VR of the right arm, the chest and the back of the working garments, 9 jackets with different sizes and fabric permeability (permeable, semi-permeable and impermeable) were made. The results showed that the local VR for each garment location were significantly different. The chest had the largest local VR. Clothing ventilation rates were not liner with garment sizes. Closing garment bottom decreased more air exchange for chest and back comparatively. Wind increased both local and whole VR significantly. But the impacts were different according to different locations.     

Growth,PAR use efficiency,and yield components of field-grown Vicia faba L. under different temperature and photoperiod regimes

N-fixing legume crops may be a good component of a general plan to improve cropping system efficiency. For this purpose, crop suitability to specific environments must be established. To estimate the yield potential we examined the growth and yield response of faba bean (Vicia faba L.) crops to different thermal and photoperiod regimes. Irrigated field experiments were conducted in northwest Spain for 3 years (2004–2007) with cv. ‘Alameda’ sown on five different dates in each year from mid-autumn to mid-spring. Environmental conditions experienced by plants across sowing dates were largely different. Sowing date had a great influence on biomass, grain yield and its components. This effect was associated with changes in PAR captured, PAR use efficiency (PUE) and biomass allocation to the different organs. Critical leaf area index (LAI_cr) tended to increase and the extinction coefficient, k, to decrease as the sowing date was delayed. Earlier sowing dates intercepted more radiation over the whole season than the spring sowing dates. Greatest crop growth treatments (2nd and 3rd sowing dates) had the highest values of PAR use efficiency probably due to more adequate temperatures for photosynthesis and a large number of reproductive sinks. The highest grain yield (7733 kg ha⁻¹) was obtained with the mid-February sowing date, which produced the most pods and seeds per m², the largest harvest index (62.0%), and large maximum leaf area index (5.41). Low yields of mid-autumn (1st) and mid-spring (5th) sowing dates were associated with reduced pods and seeds per m². Temperature and photoperiod had a large impact on faba bean growth, development, and yield. Best yields were obtained when abundant assimilate supply and moderate temperatures were available during pod set.     

Development and testing of a surface roughness measurement device based on aerial ultrasonic reflections

Paddy and Water Environment - Repairs of concrete irrigation channels in Japan are guided to a large extent by the degree to which their walls have degraded over decades of use. Current methods of...     

Weight loss of potatoes as affected by age,temperature, relative humidity and air velocity

The factors affecting potato tuber weight loss were studied by suspending individual tubers of Kennebec, Red Pontiac, and Norgold Russet potatoes in chambers where temperature, relative humidity, and air flow past the tubers could be controlled. The results of a regression analysis indicated that the age of the tubers closely followed by temperature was most highly correlated to weight loss. Tuber weight and relative humidity were next and about equally correlated with weight loss. Air velocity had the lowest correlation coefficient Prediction equations for predicting the weight loss of the potato tubers as a function of the various environmental and potato tuber variables were developed from a step-wise regression analysis program. The standard error for these regression equations was about ±1.5% weight loss from the predicted value The weight loss of the tubers in this experiment are likely higher than bulk stored potatoes because of the greater surface area exposed to air flow. Also, other than temperature, the other variables (air velocity, relative humidity, and potato weight) were relatively uncontrolled and therefore had high variations. A plot of weight loss versus time indicates a non-linear response with greater variation as time increases.     

不同栽培密度对棉花产量及经济性状的影响

在高肥水的栽培条件下。研究了不同栽培密度下单株铃数、单铃重、表分及皮棉产量的变化，并进行关联度分析，并确定各因素与密度之间的关联序。蛄果表明．在12000-57000株／hm^2的栽培密度范围内，随着密度的增加，单株铃数逐渐减少．而单铃重、表分的变化很小，皮棉产量有下降的趋势，在12000株／hm^2栽培密度下皮棉产量最低。在21000株／hm^2的栽培密度下单株铃数最多、单铃重最大、皮棉产量最高。     

Yield and yield components of saffron under different cropping systems

This study was conducted to evaluate yield and yield components of saffron (Crocus sativus L.) in response to (i) production system (PS) (irrigated vs. non-irrigated); (ii) corm size (CS) (medium −2.25 to 3 cm diameter vs. small corms <2.25 cm diameter); (iii) planting depth (PD) (10 cm vs. 20 cm); and iv) planting density (PDEN) (51 corms m⁻² vs. 69 corms m⁻²).This fully replicated multifactorial design was started in August 2000, and carried through November 2003, when the fourth saffron harvest took place. The total and average fresh weight of stigmas, and the number of flowers were measured at each harvest.Results indicate that three of the four factors tested (PS, CS and PD) had a significant effect on the quantitative yield during the two most productive flowering years (2001 and 2002) and on the total flowering. Irrigated cultivation, medium size corms and 10 cm planting depth had the greatest effect in increasing the quantitative production of saffron.Yield was also affected by planting density in contrasting ways. Whereas at high PDEN yield increased per unit of surface, at low PDEN, yield increased with respect to the initial number of corms planted.The fresh weight of stigmas per flower yield component, an important aspect that determines the quality of the spice, was enhanced when corms were planted at 20 cm depth and when irrigation was applied to the crop.     

Predicting the date of harvest of vining peas by means of air and soil temperature sums and node countings

Predictions of the date of harvest of vining peas (Pisum sativum L.) were performed by means of statistical models. Simple models based on sowing-to-harvest prediction criteria and two-component models based on a combination of sowing-to-emergence and emergence-to-harvest prediction criteria were applied. The criteria used were number of days, and soil and air temperature sums, with base temperature in the range 2.6–3.8°C and 3.0–6.0°C, respectively.The best predictions of the harvest date were obtained with two-component models, and sowing-to-emergence predictions criteria based on soil temperature were better than others examined. Among two-component models, the smallest error of prediction-2.4 days-was obtained with the model using sowing-to-emergence soil temperature sums with base temperature 3.0°C, and emergence-to-harvest number of days as prediction criteria. The prediction model traditionally used in practice applies sowing-to-harvest air temperature sums with base temperature 4.5°C as prediction criterion, and the error of prediction of this model was 4.3 days.Close linear relationships were found between number of nodes and air temperature sums accumulated from sowing or emergence. In consequence, the number of nodes is a reliable indicator of the actual air temperature sum status of the crop.Some practical aspects of applying two-component models and node counting for predicting the date of harvest of vining peas are discussed.     

Aflatoxin contamination of corn under different agro-environmental conditions and biocontrol applications

Biological control of the fungus Aspergillus flavus has been shown to be effective in reducing aflatoxin contamination in corn. This study compared field application of a bioplastic-based formulation for delivering atoxigenic A. flavus isolates in Northern Italy and the Mississippi Delta.Due to an extremely hot and dry summer at the Italy site in 2012, aflatoxin contamination was approximately seven times higher than in 2011. In 2011, and 2012, application of bioplastic granules inoculated with the atoxigenic isolate A. flavus NRRL 30797 at 15 and 30 kg ha⁻¹ resulted in a reduction of aflatoxin contamination by 67.2 ± 4.1% and 94.8 ± 5.3%, respectively. The higher application rate was also effective when soil abundance of A. flavus was artificially increased by applying contaminated corn residues. At the Mississippi site, summer 2012 was also hot and dry, with high levels of aflatoxin contamination. In fields planted with non-Bt or Bt hybrids, application of biocontrol granules inoculated with A. flavus NRRL 30797 or NRRL 21882 at 30 kg ha⁻¹ reduced aflatoxin contamination to up to 89.6%. Field experiments on two continents showed that bioplastic-based A. flavus formulations markedly reduced aflatoxin contamination under different agro-environmental conditions and infestation intensities.     

不同光照条件下大豆体内异黄酮的含量与分布

用ＨＰＬＣ检测了不同光照处理大豆组织中异黄酮的含量。结果显示：幼苗子叶异黄酮含量大大高于叶片和根中的含量;光照处理后,子叶中异黄酮的含量降低,而叶片和根中的异黄酮含量上升;异黄酮含量较低的品种,幼苗光照后子叶中异黄酮含量上升较多。幼苗子叶中的异黄酮以大豆甙和染料木甙及其丙二酰衍生物为主,叶片中主要含有染料木甙及其丙二酰衍生物,根中异黄酮组分以丙二酰大豆甙为主;异黄酮组分因品种不同显示出一定差异。     

不同转化时间、不同转化温度对甘蔗品质指标的影响分析

甘蔗蔗汁转化转光度的分析是整个甘蔗品质分析的重要步骤,用恒温水浴摇床对不同转化时间、不同转化温度作试验,结果对甘蔗蔗汁转化转光度的影响达极显著水平,对甘蔗蔗糖分也达极显著水平,从不同转化时间的变异系数CV%的变化判断,转化时间10min时变异系数CV%最小;从不同的转化温度变化来看,60℃、65℃、70℃在不同的转化时间中,在60℃、10min时呈最大值.