Mixing behaviour of a zero-developed dough compared to a flour–water mixture

The Z-blade mixing behaviour of zero-developed (ZD) doughs from the flours of two wheat cultivars of different gluten strength was compared to that of conventionally mixed dough made from the same flours. In farinograph experiments, use of ZD dough led to shorter development time (with less energy requirement), less stability time, and consequently earlier breakdown compared to conventional mixing of the corresponding flour–water mixture. Mixing of ZD doughs led to an almost similar decrease of glutenin macro-polymer (GMP) wet weight as that of doughs prepared from flour–water mixtures. However, comparison of wet weight of re-assembled GMP revealed that until time-to-peak (TTP) mixing, there was no difference in GMP recovery with respect to the starting material used in the z-blade mixing experiments. Beyond TTP, recovery of GMP in doughs prepared from both starting materials was reduced. The results of large-strain deformation rheology showed strong visco-elastic behaviour as characterised by the highest values of fracture properties (except ε_H), followed by a decline in those properties upon further mixing for doughs mixed from both flour–water mixture and ZD dough from both types of wheat cultivars. It was concluded that at mixing regimes before TTP, there was no difference between ZD doughs and flour–water mixtures in the mixer. When ZD dough is used as a starting material for dough preparation instead of flour, extra care should be taken not to over-mix the developing dough.     

A comparison of buffer and partial storage feeding of a straw/concentrate mixture to grazing dairy cows

A straw/concentrate mixture was offered to set-stocked dairy cows over a 24-week period. The cows were offered grazed herbage only (G), or grazed herbage with a straw/concentrate supplement offered either for 45 min after each milking (B), or overnight (P). The overnight treatment involved housing the cows between afternoon and morning milking. The straw/concentrate mixture contained 0·33 long barley straw, 0·28 barley, 0·12 soya bean meal, 0·25 molaferm and 0·02 minerals. During the first 8 weeks of the experiment an average of 2·25 kg of concentrate were fed, and from weeks 9–24, 2·0 kg of concentrate were fed.
The feeding of the straw/concentrate mixture led to a decrease in estimated herbage dry matter (DM) intake, particularly for treatment P. Estimated total DM intakes were increased throughout the experiment by offering the straw/concentrate mixture. However, total metabolizable energy (ME) intakes were only increased in mid-and late season.
Milk yield was higher in early season for treatment G; 28·1 kg d⁻¹ compared to 26·8 kg d⁻¹ and 25·5 kg d⁻¹ for treatments B and P respectively. In late season the cows in treatment G had lower milk yields; 13·3 kg d⁻¹ compared to 15·5 kg d⁻¹ and 16·8 kg d⁻¹ for treatments B and P respectively. Milk fat content was increased in early season in treatment P, and milk protein content tended to be reduced throughout the experiment for cows offered the straw/concentrate mixture overnight. Over the whole experiment there were no differences in yield of milk solids.     

大豆锈病越冬区气候区划研究

根据1951-2001年间全国743个气象站点的气象数据,结合大豆锈病越冬所需气候条件,采用地理信息系统分析获得了大豆锈病在我国越冬区区划图,以供我国各个地区统一协调管理大豆锈病时参考使用.根据生物气候相似距原理,以琼海为中心,以计算的前一年12月初到下一年2月底的时间段内各个旬均温、月最高温、月最低温、旬降雨量为气候要素,计算琼海与其余742个气象站点的气候相似距,用地理信息系统软件Arcmap对相似距值按Kriging法进行插值,生成的地图表明,大豆锈病可在海南岛、广东南部较大范围内越冬,而云南和广西只有局部地区适合大豆锈病越冬.该区划结果需要进一步实地调查验证.     

Neutron activation analysis using dysprosium as a tracer to measure spray drift

Neutron activation analysis was used to determine the level of dysprosium (Dy) in spray deposits within and up to 100 m downwind from plots of winter wheat treated with an Ulvamast (Mk2) sprayer. Spray was collected on filter papers positioned horizontally 0, 0·45 and 0·75 m above the ground at 10, 30 and 100 m downwind and 36 m upwind within the sprayed plots. The minimum detectable quantity of dysprosium was found to be 1·62 × 10^?3 μg for a filter paper matrix. The concentration of dysprosium on ground collecting surfaces was significantly higher than at other sampling heights. Deposits within the sprayed areas were significantly higher than at all sampling points downwind. There was no significant difference between the deposits measured at different distances downwind or between the samples taken at different heights above the ground. Samples from the field can be sent for neutron activation analysis to the Imperial College Reactor, which has suitable facilities. This technique has the advantages of sensitivity, safety in the field, speed of analysis and reasonably low cost when compared with other quantitative techniques which require expensive solvents for extraction.     

Using the Gluten Peak Tester as a tool to measure physical properties of gluten

The functional properties of wheat are largely dictated by composition and interactions of the gluten proteins. All flours contain gliadin and glutenin, but produce baked products of varying quality, which provides evidence that gluten proteins from different wheats possess different properties. A common method to study differences in gluten properties, which is utilized in this study, is fractionation/reconstitution experiments to understand how various gliadin to glutenin ratios and how fractions from different wheat sources affect gluten aggregation properties. Gliadin and glutenin from a vital wheat gluten were fractionated with 70% ethanol and reconstituted at various gliadin to glutenin ratios. Gliadin and glutenin from a Canadian eastern soft, eastern hard and western hard wheat (14% moisture) were fractionated and substituted between flours at the native gliadin to glutenin ratio. Gluten combinations were evaluated with a Gluten Peak Tester at constant temperature and mixing. Varying gliadin to glutenin ratio showed that 50:50 is optimal for fast gluten aggregation while amount of glutenin dictates strength. Substitution experiments showed that replacing good quality gluten fractions with those from a lower quality wheat decreases gluten quality, and vice versa. Data also showed that cultivar specific differences in gliadin and glutenin are more important in dictating gluten strength (torque), while gliadin to glutenin ratio dictates aggregation time (PMT) independent of the source of fractions. The study demonstrated the ability of the improved method to evaluate gluten aggregation by controlling for all variables except the one being tested. The data also revealed information about gluten aggregation properties never before seen.     

Using the Gluten Peak Tester as a tool to measure physical properties of gluten

The functional properties of wheat are largely dictated by composition and interactions of the gluten proteins. All flours contain gliadin and glutenin, but produce baked products of varying quality, which provides evidence that gluten proteins from different wheats possess different properties. A common method to study differences in gluten properties, which is utilized in this study, is fractionation/reconstitution experiments to understand how various gliadin to glutenin ratios and how fractions from different wheat sources affect gluten aggregation properties. Gliadin and glutenin from a vital wheat gluten were fractionated with 70% ethanol and reconstituted at various gliadin to glutenin ratios. Gliadin and glutenin from a Canadian eastern soft, eastern hard and western hard wheat (14% moisture) were fractionated and substituted between flours at the native gliadin to glutenin ratio. Gluten combinations were evaluated with a Gluten Peak Tester at constant temperature and mixing. Varying gliadin to glutenin ratio showed that 50:50 is optimal for fast gluten aggregation while amount of glutenin dictates strength. Substitution experiments showed that replacing good quality gluten fractions with those from a lower quality wheat decreases gluten quality, and vice versa. Data also showed that cultivar specific differences in gliadin and glutenin are more important in dictating gluten strength (torque), while gliadin to glutenin ratio dictates aggregation time (PMT) independent of the source of fractions. The study demonstrated the ability of the improved method to evaluate gluten aggregation by controlling for all variables except the one being tested. The data also revealed information about gluten aggregation properties never before seen.     

Selection of a compatible biocontrol strain mixture based on co-cultivation to control rhizome rot of ginger

Rhizobacteria and Trichoderma spp. that were antagonistic against Fusarium oxysporum f.sp. zingiberi and Pythium splendens inciting rhizome rot disease of ginger were identified. In vitro assays identified positive interactions for growth, antifungal and chitinase gene expression between antagonistic TEPF-Sungal (Burkholderia cepacia) and S2BC-1 (Bacillus subtilis) with S17TH (Trichoderma harzianum), and vice versa. In comparison with the other strains and strain mixtures, one strain mixture, TEPF-Sungal + S17TH, recorded a maximum rhizome production of 84% efficiency with less incidences of yellows and rhizome rot at an 84.2 and 79.7% reduction over the pathogen control, respectively, in a polyhouse with a challenge inoculation with the pathogens. Inoculation of the mixture of biocontrol agents was associated with an increase in known defence gene products such as chitinase etc., so we speculate that these are involved in the mechanism of disease suppression. In field experiments, the strain mixture reduced yellows and rhizome rot to 45.9 and 49.3% over the untreated control, respectively, which is comparatively better than that produced with fungicide (44.3 and 45.3%, respectively). The treatment also produced an increased rhizome yield with an average increase of 60.0% relative to the control.     

A novel concept for the control of parasitic weeds by decomposing germination stimulants prior to action

A new concept for controlling parasitic weeds is described. By decomposing germination stimulants prior to action no germination of seeds can take place anymore. Ethanol fractions of the strigolactone (SL) analogues viz., the standard synthetic analogues GR 24 and Nijmegen-1, and analogues derived from tetralone and coumarine, were added to an aqueous buffer with a pH ranging from 6 to 8 and the half lifes (t_1/2) of the hydrolysis were measured. Nijmegen-1 hydrolysed faster than GR 24 and the analogue from tetralone was the most stable one at all pH's. It was found that the aqueous solutions of either borax or thiourea rapidly decompose typical SL analogues, including GR 24 and Nijmegen-1, within an hour. The hydrolysis of SLs by borax was monitored with UV spectroscopy and for thiourea gas chromatography was used. This decomposition of SLs by either borax or thiourea in natural conditions would deprive the seeds of the parasitic weeds of the essential germination stimulants and as a consequence not allow them to germinate. Hence, conditions for an effective weed control are fulfilled.     

Self-made microlysimeters to measure soil evaporation: a test on aerobic rice in northern Italy

Soil water balance researches aimed at improving crop water use efficiency often require the determination of soil evaporation. In this technical note, the performance of simple and cheap self-made microlysimeters for the measurement of soil evaporation was tested in an aerobic rice field managed by intermittent irrigation. Six microlysimeters obtained by cutting commercial PVC pipes and closing the bottom ends with caps were positioned in appropriate PVC outer casings installed into the soil. Three measurement campaigns (for a total of 11 measurement periods) were carried out in different vegetation cover conditions (rice development, rice maturity and after the crop harvest). Evaporation amounts were analysed with respect to climatic data, vegetation cover and soil water status and, finally, compared with the simulated results of a FAO Penman–Monteith “dual crop coefficient” model implemented with site-specific data. Evaporation rates in the three campaigns were closely dependent on the evaporative demand of the atmosphere ETo (R ² = 0.96, 0.98, 0.96), while the slope of the linear regression curve was strongly related to the vegetation cover (b = 0.29, 0.12, 0.94); soil water content, always rather high during the experiments, did not affect the evaporation rate. Measured and simulated evaporation amounts showed a close agreement: the linear regression was characterized by slope and R ² of 0.98 and 0.95, while RMSE and NSE indices were 0.15 and 0.94. From the tests conducted, we can conclude that the self-made microlysimeters presented in this note are affordable instruments for measuring soil evaporation, at least in temperate climate conditions.     

浅谈提高水稻产量的几项措施

结合精细整地、培育壮秧、本田管理、精打细收等环节讨论了提高水稻产量的具体措施,并针对床土配制、苗床管理、水肥管理等细节进行详细讲述。     

Comparison of color techniques to measure the color of parboiled rice

A combination of digital camera, computer and graphic software can provide a less expensive and more versatile technique to determine the surface color of parboiled rice compared to instrumental color measurement. The instrument was used to measure rice powder and whole rice. Pearson correlation coefficients and sample paired t-test on total color difference (ΔE), L and b values were calculated. The value of ΔE of samples from the instrumental technique was 0.69–4.61 (powder), 4.7–10.2 (whole rice) with a coefficient of variance (CV) ranging from 3.5 to 25.3% and from 15.4 to 46.6%. Meanwhile, the digital image technique gave a ΔE value ranging from 4.2 to 13.77 with a CV from 6.3 to 21.2%, respectively. A highly significant correlation (R² = 0.7451, R² = 0.8074, R² = 0.7518,) was obtained for ΔE between instrumental (powder and whole rice), Vision Builder and instrumental (powder), and instrumental (whole rice) and Vision Builder. The chromatic b value of instrumental for powder had a significant correlation with the Vision Builder data (R² = 0.7741). The results suggest that although the digital image provided the surface color of parboiled rice, it was less accurate than the instrumental for powder. Therefore results from the digital image should be interpreted with caution.     

Depression of potato yields by Bordeaux mixture during a dry summer

Potatoes have been sprayed each summer for the past few years with Bordeaux mixture, DDT, zineb, and combinations of these materials in an effort to discover any possible influence they may have on chipping quality.     

The biotype concept and its application to insect pests of agriculture

The use of the term biotype of insect pests of agriculture is discussed in the broad context of species, populations and individuals. There have generally been two quite distinct usages and thus two different concepts. The first is a general concept which applies, confusingly, both to individuals and to populations of a species which share certain biological characteristics, usually concerning virulence on different host varieties, with little or no knowledge of their genetic bases. This is generally synonymous with the term host race, used by many authors. The second is a very specific concept in which a particular gene or genotype for virulence in a pest is known to correspond with a particular gene for resistance in a host plant—the gene-for-gene relationship. We argue that the first concept is so general as to be of little value, and in some examples, such as the brown planthopper of rice, is potentially misleading. The specific concept depends on detailed genetic analyses which are available for very few examples and is thus of limited applicability. We conclude that the confusion of the two distinct concepts is dangerous. It is not possible to argue from the general to the specific. The term biotype has often been used to cover our ignorance of the detail of any particular insect/plant interaction.     

Delignification of wheat straw using a mixture of carboxylic acids and peroxoacids

Wheat straw was pulping by an Organosolv process using a mixture of acetic acid/formic acid/water (AA/FA/water). In order to make easier the bleaching step, it was possible to improve the delignification in an efficient and selective manner by using peroxoacids in acidic organic medium. First a solution of peroxoacids was synthesized by adding hydrogen peroxide in a mixture of acetic acid/formic acid, without any inorganic acids as catalyst. Then this mixture was added to the unbleached pulp. Several parameters (temperature, extraction alkaline, reaction time …) were investigated.This simple and innovative way to use peroxoacids allows to overcome problem due to the control of their stability in aqueous medium and proves to be perfectly complementary to the cooking method in a carboxylic acid medium. Low kappa numbers and high viscosity were obtained. Strength properties of the pulp after the peroxoacids step were improved.     

A quantitative model of the ensilage process in lactate silages

A model of the ensilage process is presented which can be used to predict silage quality in lactate silages. The model simulates the major microbial and biochemical processes during ensilage, including aerobic respiration, hydrolysis of hemicellulose. growth and death of lactic acid bacteria and their production of lactic and acetic acids, reduction in pH, change in soluble sugar content, increase in osmotic potential, and proteolysis. The model is designed to operate on mixtures of grasses, legumes, or whole-plant corn. Parameters for the model are developed from published silage experiments and pure-culture bacterial studies. The model gives reasonably accurate predictions of key silage quality parameters, but further experimental work is needed on growth of lactic acid bacteria and on plant-enzyme proteolysis. Predicted final pH depends primarily on the pH at which bacterial growth and death rates are equal. Initial bacterial concentration affects the time to rapid pH change, while maximum bacterial growth rate affects the rate of decline thereafter.