How pristine are tropical forests? An ecological perspective on the pre-Columbian human footprint in Amazonia and implications for contemporary conservation

Archeologists, paleoecologists and anthropologists argue that ecologists need to give greater consideration to the pre-historical influence of humans in shaping the current structure and composition of tropical forests. We examine these arguments within the context of Amazonia, and assess the extent to which (i) the concepts of “pristine forests” and “cultural parklands” are mutually exclusive, (ii) the aggregated distribution of some plants necessarily indicates enrichment planting, (iii) pre-Columbian human disturbance has increased forest biodiversity, (iv) pre-Columbian indigenous practices were always sustainable, and (v) if indeed, the ecological impacts of pre-Columbian peoples are relevant for modern biodiversity conservation. Overall, we reject the notion that “the pristine myth has been thoroughly debunked” by archeological evidence, and suggest that the environmental impacts of historical peoples occurred along gradients, with high-impacts in settlements and patches of Amazonian Dark Earth (ADE), lesser impacts where occasional enrichment planting took place in forests surrounding agricultural plots, and a very low influence (in terms of light hunting pressure and other types of resource extraction) across vast areas of Amazonia that may always have been far from permanent settlements and navigable rivers. We suggest that the spatial distribution of pre-Columbian finds is given more attention, and urge caution before case studies are extrapolated to the entire Basin. Above all, we feel that debates over “naturalness” and environmental impacts of pre-Columbian humans are of limited relevance to present and future biodiversity conservation, and can detract from the major challenges facing Amazonia and other tropical forest regions today.     

Using webinars to extend the reach of soil learning in New South Wales: A first look

Increasingly knowledge is shared using new web‐based channels. The use of these channels is relatively new in the realm of soil science. However, they may prove to be very useful for connecting time‐poor, geographically dispersed audiences in an efficient and cost‐effective way. There has been limited study of this form of knowledge sharing for natural science (let alone soil science). In New South Wales (NSW), Australia, the NSW Department of Primary Industries (NSW DPI) has coordinated the Soil Network of Knowledge (SNoK) monthly webinar over 3 years, with over 40 webinars targeting an audience of next users of soil information. Aggregated data collected from these webinars indicated that the majority of information is used for professional development by participants. Whether this will eventually lead to on‐ground practice change because of the improved professional and technical knowledge of participants is still a moot point and will require further investigation over time. The information collected on attendance and participation showed that webinars are a good way to connect with some target audiences such as other government bodies that have a historical relationship with NSW DPI. However, other target audiences that NSW DPI has always found difficulty in engaging, such as private advisers, require more active overtures to drive participation. The growing subscriber base is encouraging.     

Degradation of phosphonates. breakdown of soman (O-pinacolyl-methylphosphonofluoridate in wheat plants

The fate of pinacolyl methylphosphonofluoridate (Soman) in wheat has been studied. Using wheat grown in hydroponic culture and applying the compound Soman via the culture solution, it has been shown that Soman is rapidly hydrolysed in the plants and that the resulting pinacolyl hydrogen methylphosphonate is further degraded to methylphosphonic acid.     

The structure-activity relationship in herbicidal monosubstituted sulfonylureas

BACKGROUND: The herbicide sulfonylurea (SU) belongs to one of the most important class of herbicides worldwide. It is well known for its ecofriendly, extreme low toxicity towards mammals and ultralow dosage application. The original inventor, G Levitt, set out structure–activity relationship (SAR) guidelines for SU structural design to attain superhigh bioactivity. A new approach to SU molecular design has been developed. RESULTS: After the analysis of scores of SU products by X‐ray diffraction methodology and after greenhouse herbicidal screening of 900 novel SU structures synthesised in the authors' laboratory, it was found that several SU structures containing a monosubstituted pyrimidine moiety retain excellent herbicidal characteristics, which has led to partial revision of the Levitt guidelines. CONCLUSIONS: Among the novel SU molecules, monosulfuron and monosulfuron‐ester have been developed into two new herbicides that have been officially approved for field application and applied in millet and wheat fields in China. A systematic structural study of the new substrate–target complex and the relative mode of action in comparison with conventional SU has been carried out. A new mode of action has been postulated. Copyright © 2011 Society of Chemical Industry     

Fortification of Wheat Dough with Calcium and Magnesium Ions Affects Empirical Rheological Properties

This study evaluated the influence of calcium and magnesium ions on the empirical rheological properties of wheat flour to verify possible effects of these ions on processing because, in addition to their nutritional importance, they are also responsible for water hardness. Calcium (0–1.30 g/100 g) and magnesium (0–0.34 g/100 g) ions from sulfate salts were added to wheat flour, according to a central composite rotatable design. The farinograph and extensigraph properties of wheat flour and its mixtures were evaluated. The results were analyzed by response surface methodology. Calcium ions stood out for increasing water absorption, decreasing mixing stability, and producing a delayed effect on dough extensibility (reduced at 135 min). Magnesium ions influenced most flour rheological properties in a similar manner to oxidizing agents (increased dough stability, increased resistance to extension, and reduced extensibility), thus proving to be a possible replacement agent for these additives. An interaction effect of the combined calcium and magnesium ions was observed on dough development time. The results showed that effects on processing can occur when wheat flour fortification is made, and adaptations on wheat flour specifications, product formulation, and processing parameters may be required.     

地膜残留量对新疆棉田蒸散及棵间蒸发的影响

为探讨残膜对干旱区农田蒸散耗水特征的影响,在新疆阿克苏典型覆膜滴灌棉田开展2 a小区试验研究,设计0、225、450 kg/hm2共3种不同的地膜残留量,采用水量平衡法,微型棵间蒸发仪法,于主要生育时期测定并计算土壤含水量、蒸散量、棵间蒸发量、作物蒸腾量、棵间蒸发占蒸散的比例。结果表明:随着地膜残留量增加棵间蒸发量、棵间蒸发占蒸散的比例呈增大趋势,而蒸散量及作物蒸腾量则逐渐减小。与无残膜处理相比,225和450 kg/hm2处理全生育期田间无效耗水的棵间蒸发量分别增加了9.27和22.20 mm,棵间蒸发占蒸散的比例增幅分别为2.6%和6.1%,作物蒸腾量降低34.89和55.94 mm。在棉花生育期内,棵间蒸发占蒸散的比例(E/ET)与叶面积指数(leaf area index,LAI)呈幂函数关系,各处理间棵间蒸发占蒸散的比例对叶面积指数的响应差异不同,450 kg/hm2处理蒸发占蒸散的比例随着LAI的增加,曲线下降趋势较明显;无残膜处理棵间蒸发占蒸散的比例与LAI的决定系数最高,均在0.9以上。土壤水分利用率也随残膜量的增加依次降低,当残膜量由0增加到450 kg/hm2时,土壤水分利用率从28.25%降至24.91%,可见,残膜增大了农田的无效耗水,不利于土壤水分的有效利用。研究可为制定缓解或克服残膜危害的应变调控技术提供依据。     

Infiltration characteristics of volcanic sloping soils on Mt. Elgon,Eastern Uganda

Water infiltration is an important hydrological process that influences runoff and soil loss patterns in mountain ecosystems. In this paper, we present results on spatial variation in infiltration in croplands on the volcanic soils of Mt. Elgon, in Eastern Uganda. Twelve experimental sites with slope gradients ranging from 12 to 32% were established. Infiltration tests were carried out with a double ring infiltrometer and three measurements were taken at the upper, middle and lower sections of each experimental site to assess the local variability of infiltration. In addition soil information was collected on each experimental site. The soil infiltration data were then evaluated to fit to four commonly used water infiltration models: (1) Philip (1957), (2) Green–Ampt (1911), (3) Horton (1940) and (4) Kostiakov (1932). The twelve experimental sites cover two cropping systems: annual (6 sites) and perennial (6 sites) crops. Based on the results, we examine the spatial variability of infiltration, the relationship of infiltration to landscape position, and the influence of soil composition on infiltration rates on the slopes. The factors affecting spatial variability of soil infiltration were analysed using correlation and regression techniques. Steady state infiltration rates generally increased with the slope gradient and were crop type independent (P < 0.05). The performance of the four applied water infiltration models was generally good with mean R² values ranging from 0.79 to 0.87, although all the models tended to over-predict the steady state infiltration rates at most sites. Overall, the Philip's and Kostiakov gave better results than the Horton and Green–Ampt models in reproducing the infiltration process on Mt. Elgon.     

Effect of Adding Different Dietary Fiber Sources on Farinographic Parameters of Wheat Flour

Breadmaking is a complex process that involves a series of parameters that must be controlled. Rheological measurements are often used to predict the behavior of wheat dough during processing and the quality of the final product. There are many different dietary fiber sources that can be used to enhance the nutritional quality of bread. However, they will affect processing and final product quality. Response surface methodology (RSM) was employed to study the effects of adding different dietary fiber sources (wheat bran, resistant starch, and locust bean gum) on farinographic parameters of wheat flour. The experiments were conducted according to a 2³ central composite rotational design (CCRD). With the experimental results or responses (farinographic parameters), the effect of each variable was calculated and the interactions between them were determined. Models that explain the effects of the different fiber sources on water absorption, arrival time, dough development time, and mixing tolerance index of wheat flour were established. The fiber sources interacted for some of the parameters analyzed, demonstrating that if two or more sources of dietary fiber are present in the mix, they might act different to what would be expected of the sum of them. It was also noticed that for most parameters, wheat bran and locust bean gum had a greater influence on farinographic parameters than resistant starch. The simultaneous presence of the three fibers, within the ranges studied, contributed to an increase in water absorption, arrival time, and mixing tolerance index, and to a reduction in departure time and dough stability.     

Effect of fluoride on axenic cultures of diatoms

Algal bioassay studies on the effect of F concentrations on diatoms Nitzschia palea (freshwater) and Amphora coffeaeformis (brackishwater) were conducted in the laboratory. Significant enhancement of growth occurred in N. palea at F concentrations between 10 and 110 mg L^?1. In A. coffeaeformis statistically significant stimulation occurred at 70 mg L^?1 F and above 90 mg L^?1 F the growth declined. The results indicate that the diatom N. palea and A. coffeaeformis can tolerate high F concentration.