Density and Seasonal Dynamics of Bemisia tabaci(Gennadius) Mediterranean on Common Crops and Weeds Around Cotton Fields in Northern China

The density seasonal dynamics of Bemisia tabaci MED were evaluated over two years in a cotton-growing area in Langfang, Hebei Province, northern China on cotton （Gossypium hirsutum L.） and six other co-occurring common plants, common ragweed （Ambrosia artemisiifolia L.）, piemarker （Abutilon theophrasti Medicus）, sunflower （Helianthus annuus L.）, sweet potato （Ipomoea batatas L.）, soybean （Glycine max L.）, and maize （Zea mays L.）. The whitefly species identity was repeatedly tested and confirmed; seasonal dynamics on the various host plants were standardized by the quartile method. B. tabaci MED appeared on weeds （the common ragweed and piemarker） about 10 days earlier than on cotton, or the other cultivated plants. The peak population densities were observed over a span of 2 to 3 weeks on cotton, starting in early （2010） or mid-August （2011）. The common ragweed growing adjacent to cotton supported the highest B. tabaci densities （no. on 100 cm2 leaf surface）, 12-22 fold higher than on cotton itself. Sunflower supported more B. tabaci than the other plants, and about 1.5-2 fold higher than cotton did, Our results indicate that weeds （esp. the common ragweed） around cotton fields could increase the population density of B. tabaci MED on cotton, while sunflower could act as a trap crop for decreasing pest pressure on cotton.

Effects of reclaimed water irrigation and nitrogen fertilization on the chemical properties and microbial community of soil

The ecological effect of reclaimed water irrigation and fertilizer application on the soil environment is receiving more attention.Soil microbial activity and nitrogen（N）levels are important indicators of the effect of reclaimed water irrigation on environment.This study evaluated soil physicochemical properties and microbial community structure in soils irrigated with reclaimed water and receiving varied amounts of N fertilizer.The results indicated that the reclaimed water irrigation increased soil electrical conductivity（EC）and soil water content（SWC）.The N treatment has highly significant effect on the ACE,Chao,Shannon（H）and Coverage indices.Based on a 16S ribosomal RNA（16S rRNA）sequence analysis,the Proteobacteria,Gemmatimonadetes and Bacteroidetes were more abundant in soil irrigated with reclaimed water than in soil irrigated with clean water.Stronger clustering of microbial communities using either clean or reclaimed water for irrigation indicated that the type of irrigation water may have a greater influence on the structure of soil microbial community than N fertilizer treatment.Based on a canonical correspondence analysis（CCA）between the species of soil microbes and the chemical properties of the soil,which indicated that nitrate N（NO3-–-N）and total phosphorus（TP）had significant impact on abundance of Verrucomicrobia and Gemmatimonadetes,meanwhile the p H and organic matter（OM）had impact on abundance of Firmicutes and Actinobacteria significantly.It was beneficial to the improvement of soil bacterial activity and fertility under 120 mg kg^-1 N with reclaimed water irrigation.

Recreational potential as an indicator of accessibility control in protected mountain forest areas

The article presents research findings related to recreational use of forests located in protected mountainous areas with forestage of over 80%. The study was designed to identify recreational potential of the Carpathian national parks （Bieszczady National Park, Bahia G6ra National Park, Goree National Park and Magura National Park; southern Poland） and to compare these findings with the actual number of visitors. The information received on the recreational potential of parks is important from the point of view of protection of natural resources and the financial situation of the parks. The calculated ratio may be an effective tool of management for park administration, that allows to reconcile statutory social and protective functions of national parks. The study determined the recreational potential of the forests with the use of recreational valorisation method designed for areas with varied terrain, and the evaluated factors included the stands of trees with their habitat and land relief. The permissible number of national park visitors, expressed as man- hour/ha/year ranges from 19.31 in Bieszczady National Park （BG： 19~ 35＇ E, 49~ 35＇ N） to 32.06 in in Bieszczady National Park （B： 22~ 40＇ E, 49~ lo＇ N）. In 3 out of 4 investigated parks, Magura National Park （M： 21025＇ E, 49~ 30＇ N）, Gorce National Park （G： 20~ lo＇ E, 49~ 35＇ N）, B） recreation carrying capacity was not exceeded, whether or not the strictly protected area is taken into account. Only in BG was the recreation carrying capacity exceeded by nearly 24%, or by 85% if the strictly protected area isexcluded from tourism-related exploitation. The presented procedure for monitoring access to mountain forests in national parks, from the viewpoint of natural resources conservation, can be applied in other mountainous areas covered with forests and exposed to tourist and recreational traffic, and in forests facing particular risk of recreational damage, e.g. in urban and suburban forests growing in areas with varied orography.

Effect of row spacing and direction of sowing on yield and yield attributing characters of wheat cultivated in Western Chitwan, Nepal

A field experiment was conducted to study the growth and productivity of wheat as affected by row spacing and direction of sowing at Rampur, Chitwan, Nepal during the 2007-2008 wheat growing season. The experiment was carried out in 3-factors factorial randomized complete block design comprising two varieties (Gautam and BL-2800), three row spacings (15, 20 and25 cm) and two row directions of sowing (east-west and north-south). The effects of variety and row direction of sowing on grain yield were significant (p < 0.05), but the grain yield was not affected by the row spacing treatment. BL-2800 variety produced higher grain yield (3.53 t·ha-1) as compared to Gautam (3.11 t·ha-1). Both wheat varieties yielded about 11% higher (p < 0.05) grain in the north-south sowing as compared to the eastwest sowing.

Crambe (<i>Crambe abyssinica</i>) Cultivation under Different Levels of Fertilization with Nitrogen, Phosphorus and Potassium

The effects of fertilization on crambe are poorly understood;in this sense, this study aimed to evaluate the crambe growth under different levels of nitrogen (0, 40, 80, 120 kg&#183;ha-1), phosphorus (0, 50, 100, 150 kg&#183;ha-1), and potassium (0, 30, 60, 90 kg&#183;ha-1) in a greenhouse. The height of the plants, the production of dried biomass and that of 1000 grains of crambe were evaluated. The height of the plants was impaired as a function of increasing doses of nitrogen. The interaction of nitrogen and phosphorus in the crambe crop increased the number of grains and dry shoot biomass. The growth and yield of the crop were not influenced by the use of potassium in mineral fertilization.

Advances in studies on the physiological and molecular regulation of barley tillering

Tillering is a crucial trait closely associated with yield potential and environmental adaptation in cereal crops,regulated by the synergy of endogenous(genetic)and exogenous(environmental)factors.The physiological and molecular regulation of tillering has been intensively studied in rice and wheat.However,tillering research on barley is scarce.This review used the recent advances in bioinformatics to map all known and potential barley tiller development genes with their chromosomal genetic and physical positions.Many of them were mapped for the first time.We also discussed tillering regulation at genetic,physiological,and environmental levels.Moreover,we established a novel link between the genetic control of phytohormones and sugars with tillering.We provided evidence of how environmental cues and cropping systems help optimize the tiller number.This comprehensive review enhances the understanding of barley’s physiological and genetic mechanisms controlling tillering and other developmental traits.

Greenhouse Gas Emissions from Intermittently Flooded (Dambo) Rice under Different Tillage Practices in Chiota Smallholder Farming Area of Zimbabwe

Agriculture is one of the biggest sources of greenhouse gases. Rice production has been identified as one of the major sources of greenhouse gases, especially methane. However, data on the contributions of rice towards greenhouse gas emissions in tropical Africa are limited. In Zimbabwe, as in most of Sub-Saharan Africa, there are very few studies that have explored greenhouse gas emissions from agricultural lands. This study reports the first dataset on greenhouse gas emissions from intermittently flooded rice paddies in Zimbabwe. The objective of this study was to quantify greenhouse gas emissions from dambo rice under different tillage treatments, which were conventional tillage, no tillage, tied ridges, tied fallows, and mulching. Average soil nitrous oxide emissions were 5.9, 0.2, 5.4, 5.2 and 7.8 μg·m-2·hr-1 for tied fallows, conventional tillage, tied ridges, mulching and no tillage respectively. Average methane emission was 0.35 mg·m-2·hr-1 and maximum as 1.62 mg·m-2·hr-1. Average methane emissions for the different tillage systems were 0.20, 0.18, 0.45, 0.52 and 0.38 mg·m-2·hr-1 for tied fallows, conventional tillage, tied ridges, mulching and no tillage respectively. Carbon dioxide emissions were 98.1, 56.0, 69.9, 94.8 and 95.5 mg·m-2·hr-1 for tied fallows, conventional tillage, tied ridges, mulching and no tillage respectively. The estimated emissions per 150 day cropping season were 1.4, 3.6 and 0.6 kg·ha-1 for methane, carbon dioxide and nitrous oxide respectively. We concluded that intermittently saturated dambo rice Paddys are a potential source of greenhouse gases which is important to global greenhouse gas budgets, thus, they deserve more careful study.

Thoughts of a Travelling Ecologist,6 On monitoring

Monitoring.We,ecologists,hear the word nearly every day.From the most unexpected corners this word springs out,much used and abused.One one hand,it is often used by my peers to justify their work,their project or even their existence as scientists.They claim to do useful work,because they monitor some phenomenon or another.This,goes the ar-

The Effect of Phytohormones on Lavender （Lavandula Angustiflia Mill.） Organogenesis

Lavender （L. angustifolia） is a genus of flowering plants in the mint family, Lamiaceae. It is an aromatic shrub with multiple stems growing 30 to 60 cm tall. It is native to Asia, Europe and Mediterranean regions and grows on hilly areas and coastlines. The evergreen leaves are narrow and long and covered in fine hairs, which normally contain the essential oils. The leaves are also pinnately toothed, or pinnate. The plant blooms between April and June, and flowers are purple produced on violet bracts. All parts of the plant have a strong and scented odor and a bitter taste. The flowers and leaves are used as an herbal medicine. Lavender essential oil is extracted by distilling flowers and leaves, Essential oil has higher levels of linalyl acetate （40%）, butyric acid, propionic acid, valeric acid, free linalool. Considering the lack of information about lavender tissue culture, the current experiment＇ was aimed to study the effect of phytohormones on lavender callus induction and organogenesis. The lavender explants （leaf and apical meristem） were cultured onto MS media supplemented with different phytohormones. According to the observations, 5 mg/L NAA and 5 mg/L KIN treatment caused leaf and root formation, which were originally derived t^om dense and green calli. The MS medium containing 5 mg/L IBA and 5 mg/L Kin was effective just on leafy explants so that explants formed into leaves after callus induction. Application of 5 mg/L NAA and 5 mg/L BAP on apical meristem explants produced shoot and root after callus induction. However, complete plants were produced after sub-culturing the samples. In conclusion, MS medium supplemented with 5 mg/L NAA and 5 mg/L BAP was selected as the best medium for lavender tissue culture.

Assessing the response of dryland barley yield to climate variability in semi-arid regions,Iran

Precipitation and temperature are the most abiotic factors that greatly impact the yield of crop,particularly in dryland.Barley,as the main cereal is predominantly cultivated in dryland and the livelihood of smallholders depends on the production of this crop,particularly in arid and semi-arid regions.This study aimed to investigate the response of the grain yield of dryland barley to temperature and precipitation variations at annual,seasonal and monthly scales in seven counties of East and West Azerbaijan provinces in northwestern Iran during 1991-2010.Humidity index(HI)was calculated and its relationship with dryland barley yield was evaluated at annual and monthly scales.The results showed that the minimum,maximum and mean temperatures increased by 0.19℃/a,0.11℃/a and 0.10℃/a,respectively,while annual precipitation decreased by 0.80 mm/a during 1991-2010.Climate in study area has become drier by 0.22/a in annual HI during the study period.Negative effects of increasing temperature on the grain yield of dryland barley were more severe than the positive effects of increasing precipitation.Besides,weather variations in April and May were related more to the grain yield of dryland barley than those in other months.The grain yield of dryland barley was more drastically affected by the variation of annual minimum temperature comparing with other weather variables.Furthermore,our findings illustrated that the grain yield of dryland barley increased by 0.01 t/hm^(2) for each unit increase in annual HI during 1991-2010.Finally,any increase in the monthly HI led to crop yield improvement in the study area,particularly in the drier counties,i.e.,Myaneh,Tabriz and Khoy in Iran.

Quantifying major sources of uncertainty in projecting the impact of climate change on wheat grain yield in dryland environments

Modelling the impact of climate change on cropping systems is crucial to support policy-making for farmers and stakeholders.Nevertheless,there exists inherent uncertainty in such cases.General Circulation Models(GCMs)and future climate change scenarios(different Representative Concentration Pathways(RCPs)in different future time periods)are among the major sources of uncertainty in projecting the impact of climate change on crop grain yield.This study quantified the different sources of uncertainty associated with future climate change impact on wheat grain yield in dryland environments(Shiraz,Hamedan,Sanandaj,Kermanshah and Khorramabad)in eastern and southern Iran.These five representative locations can be categorized into three climate classes:arid cold(Shiraz),semi-arid cold(Hamedan and Sanandaj)and semi-arid cool(Kermanshah and Khorramabad).Accordingly,the downscaled daily outputs of 29 GCMs under two RCPs(RCP4.5 and RCP8.5)in the near future(2030s),middle future(2050s)and far future(2080s)were used as inputs for the Agricultural Production Systems sIMulator(APSIM)-wheat model.Analysis of variance(ANOVA)was employed to quantify the sources of uncertainty in projecting the impact of climate change on wheat grain yield.Years from 1980 to 2009 were regarded as the baseline period.The projection results indicated that wheat grain yield was expected to increase by 12.30%,17.10%,and 17.70%in the near future(2030s),middle future(2050s)and far future(2080s),respectively.The increases differed under different RCPs in different future time periods,ranging from 11.70%(under RCP4.5 in the 2030s)to 20.20%(under RCP8.5 in the 2080s)by averaging all GCMs and locations,implying that future wheat grain yield depended largely upon the rising CO2 concentrations.ANOVA results revealed that more than 97.22% of the variance in future wheat grain yield was explained by locations,followed by scenarios,GCMs,and their interactions.Specifically,at the semi-arid climate locations(Hamedan,Sanandaj,Kermanshah and Khorramabad),most of the variations arose from the scenarios(77.25%),while at the arid climate location(Shiraz),GCMs(54.00%)accounted for the greatest variation.Overall,the ensemble use of a wide range of GCMs should be given priority to narrow the uncertainty when projecting wheat grain yield under changing climate conditions,particularly in dryland environments characterized by large fluctuations in rainfall and temperature.Moreover,the current research suggested some GCMs(e.g.,the IPSL-CM5B-LR,CCSM4,and BNU-ESM)that made moderate effects in projecting the impact of climate change on wheat grain yield to be used to project future climate conditions in similar environments worldwide.

Thoughts of a travelling ecologist 15. Are arthropods in decline and does it matter?

The world population continues to grow, although there are signs that the trend is slowing, and the human population may actually be facing a decline (Bricker & Ibbitson,2019). Nonetheless, the human impact is now so large that it threatens numerous other species. Recent assessments of the state of the natural world underlines that extinctions are not the only relevant criterion to indicate that the human race harms other beings: since 1970, the populations of an estimated 10,000 species of vertebrates declined by over half (WWF,2014). Another striking example of human influence on the living world is on bird abundance. Domesticated chicken ( Gallus gallus domesticus ) is today the world′s most numerous bird with a standing population of 22.7 billion (FAO,2018), which is an order of magnitude greater than the standing stock of the most abundant wild bird species, the red-billed quelea ( Quelea quelea ) at approximately 1.5 billion (Craig,2010).

Linkage of microbial living communities and residues to soil organic carbon accumulation along a forest restoration gradient in southern China

Background:Forest restoration has been considered an effective method to increase soil organic carbon(SOC),whereas it remains unclear whether long-term forest restoration will continuously increase SOC.Such large uncertainties may be mainly due to the limited knowledge on how soil microorganisms will contribute to SOC accumulation over time.Methods:We simultaneously documented SOC,total phospholipid fatty acids(PLFAs),and amino sugars(AS)content across a forest restoration gradient with average stand ages of 14,49,70,and>90 years in southern China.Results:The SOC and AS continuously increased with stand age.The ratio of fungal PLFAs to bacterial PLFAs showed no change with stand age,while the ratio of fungal AS to bacterial AS significantly increased.The total microbial residue-carbon(AS-C)accounted for 0.95-1.66% in SOC across all forest restoration stages,with significantly higher in fungal residue-C(0.68-1.19%)than bacterial residue-C(0.05-0.11%).Furthermore,the contribution of total AS-C to SOC was positively correlated with clay content at 0-10 cm soil layer but negatively related to clay content at 10-20 cm soil layer.Conclusions:These findings highlight the significant contribution of AS-C to SOC accumulation along forest restoration stages,with divergent contributions from fungal residues and bacterial residues.Soil clay content with stand age significantly affects the divergent contributions of AS-C to SOC at two different soil layers.

Thoughts of a travelling ecologist 10.Will fighting exotics ever succeed?

We live in the Age of Extinctions-the call for naming our time＂Anthropocene＂is no more than hubris and escapism from this colossal sin.Although the6thmass extinction has possibly already started（Barnosky et al.,2011）,and it may prove the largest so far to be endured by life on Earth,efforts are needed not to turn this into the Age of Loneliness,when humans may find themselves Masters of the Earthbut alone（Wilson,2014）.

Thoughts of a travelling ecologist 12.The plight of the monarch butterfly

Nature conservation needs people who care about nature,and the efforts to convince people to care about the fate of nature has extensively relied on selected charismatic species,the'conservation icons'.One famous example is the great panda,Ailuropoda melanoleuca,well known as the World Wide Fund for Nature(WWF)logo.When it comes to invertebrates。

Thoughts of a travelling ecologist,7 In memoriam Tibor Jermy

My former colleague,Tibor Jermy,Hungarian entomologist,died recently,at the age of 97.He was the Director at the Plant Protection Institute in Hungary when I started my research career-many years ago-as a young scientist.That same year,having reached retirement age,he gladly resigned from the directorship and returned to the workbench,to continue a productive research career for another ca.30 years,before he had to give up work in the laboratory,due to his decli-

Growth and yield responses of broccoli cultivars to different rates of nitrogen in western Chitwan, Nepal

A field experiment was conducted with the objective to determine the optimum rate of nitrogen (N) fertilizer for effective growth and yield of two varieties of broccoli in southern plain of Nepal. The experiment was laid out with two-factorial completely random block design (RCBD) comprising two varieties of broccoli (Calabrese and Green Sprouting) and five N rates (0, 50, 100, 150 and 200 kg ha-1) with three replication in each treatment combinations. The effects of variety and N rate on total curd yield were significant but the interaction effect was non-significant. Green Sprouting produced 11% higher total curd than Calabrese. Similarly, curd production increased N rate up to 200 kg ha-1 reaching a maximum of 14.47 t ha-1. This indicated that optimum level of N could be beyond the rates tested in this study, which needs further experimentation.

Tissue Culture of Calla Lily (Zantedeschia spreng.): An Updated Review on the Present Scenario and Future Prospects

The calla lily(Zantedeschia spreng.)is a bulbousflower native to the tropical regions of Africa.Calla lily has gained significant popularity in the international market owing to its intricate morphology and prolonged flowering duration.Despite such advantages,for two sub-groups of calla lily,known as group Zantedeschia and group Aestivae,there are challenges in terms of hybrid production due to the‘plastome-genome incompatibility’there-between.Tissue culture is a fundamental biotechnological tool used in gene editing research,with a focus on disease resistance andflower color in calla lily breeding programs.The present review provides a brief background on the history and development of the calla lily,as well as a comprehensive and critical summary of calla lily tissue culture research.The regeneration pathways for both group Zantedeschia and group Aestivae can be divided into de novo organogenesis and somatic embryogenesis.Both groups are capable of obtaining replants through such means.However,only some species in group Aestivae have been reported to be successful in the somatic embryogenesis pathway.In the present review,special attention was paid to the influence of explant types,plant growth regulators,and culture conditions on both de novo organogenesis and somatic embryogenesis in calla lily tissue culture.Ultimately,future research prospects were determined based on integrated analysis of recent progress in calla lily tissue culture research.

Thoughts of a travelling ecologist 11.The marriage of invasion biology and social science is preordained

The human race now declared that it rules the world.We'officially'declared the start of a new era in the history of the Earth,the Anthropocene.The Executive Committee of the International Union of Geological Sciences accepted the proposal that

Thoughts of a Travelling Ecologist,4 The tale of the aphid predators: why can we expect transgenic crops to cause environmental effects?

First,let me state the obvious: ecologists have been too polite to tolerate intrusion by colleagues from other fields ( mostly from molecular biology ) who felt it necessary to pontificate about the ecological impacts of transgenic crops. Such pieces usually present,often in forceful language,the author' s belief that transgenic technology is beneficial,without negative effects,