Effect of shifting cultivation on distribution of nutrient elements and carbohydrates within water-stable aggregates in northern Iran

This study attempts to evaluate the nutrient element and carbohydrate distribution within Water-Stable Aggregates (WSA) of two natural ecosystems, native forest and pasturelands, under different land uses. Soil samples were collected from depths of (0-20) cm in Typic Haploxeroll soils. The overall pattern indicated that Mean Weight Diameter (MWD) and WSA were greater in the pasture and forest soils compared with the adjacent cultivated soils and aggregates of > 1.0 mm size were dominant in the uncultivated soils, whereas the cultivated soils comprised aggregates of the size < or = 0.5 mm. Distribution of organic carbon, nitrogen, phosphorus and carbohydrates within the WSA showed preferential enrichment of these parameters in the macroaggregate fraction (4.75-1.0 mm) for the uncultivated soils and microaggregate fraction (> 0.25 mm) for the cultivated soils. Average distribution of total exchangeable bases within WSA showed that cultivation of forest pastureland soils significantly led to reduce in these nutrient in the 4.75-2.0 mm fraction and increase in concentration of these cations in < 0.25 mm fraction. Since smaller aggregates are preferentially removed by erosion, this study emphasizes the need for sustainable soil management practices that they will minimize nutrient loss when forest or pastures lands are converted to cropland.     

Natural bee-honey based biostimulants confer salt tolerance in onion via modulation of the antioxidant defence system

Plant biostimulants are an emerging trend of crop management products which can enhance nutrient uptake, plant growth and productivity under various abiotic stresses. The ability of diluted bee-honey extract (DHE) to enhance the tolerance of onion plants to salinity stress has been investigated. Two-season field experiments were consecutively conducted in 2015/16 and 2016/17 to study the effect of 25–50 g/L DHE foliar application on growth, yield, physio-biochemical attributes, and antioxidative defence of two onion cultivars (i.e. Giza^Red and Giza-20) grown on a saline soil (EC = 8.81 dS m^?1). Results exhibited that DHE significantly increased biomass production, bulb yield and water use efficiency, leaf photosynthetic and pigments contents. Additionally, DHE applicati\on also improves osmoprotectants, membrane stability index (MSI) and relative water content (RWC), and enzymatic and non-enzymatic antioxidants of both onion cultivars in comparison with untreated control plants. In general, both cultivars showed a similar response to the DHE. Results of this study highlighted the potential impact of DHE as a promising plant bio-stimulant for overcoming the harmful effects of soil salinity stress by increasing the activity of plant antioxidative defence systems     

Climate change,migration and human rights in Bangladesh: Perspectives on governance

Bangladesh experiences some of the most severe impacts of climate change, with impacts already evident in the coastal regions. Recent data shows that around 32% of the coastal communities in Bangladesh are affected by climate‐induced hazards each year. In 2011, 64% among them were displaced locally and 27% were displaced to other locations in Bangladesh. It requires comprehensive and viable polices and planning to meet the challenges of managing a large number of displaced people. In this context, this paper reviews and investigates the effectiveness of current governance frameworks to address migration of affected communities. It argues that migration can be an effective way to cope with environmental shocks. Finally, it discusses policy imperatives for effective protection of people displaced by climate risks with a special reference to adopting a human rights‐based approach in law and policy making for climate‐induced migration.     

In-vivo evaluation of adjuvants for more effective control of celery leaf-spot (Septoria apiicola) and powdery mildew (Erysiphe graminis) of wheat with fungicides

The effects of seven adjuvants (at 0, 0.5, 1.0 and 2.0 g litre^?1) on the efficacies of four fungicides al 0.5 g litre^?1 were studied in the laboratory for the control of leaf-spot in celery (caused by Septoria apiicola) and powdery mildew on winter wheat (caused by Erysiphe graminis). The most effective fungicides for controlling leaf-spot were: tebuconazole + triadimenol = flutriafol > mancozeb + oxadixyl > prochloraz. However, addition of adjuvant to the fungicides gave a modified pattern of effectiveness. The efficacy of flutriafol was strongly enhanced by addition of all adjuvants, but those of prochloraz and mancozeb+oxadixyl only partially so. The tested adjuvants were mineral oil + surfactant, a polymer/alkoxylated alkyl ether blend, an ethoxylated alkylphenol, an ethoxylated hexitan ester blend, an ethoxylated nonylphenol and an alkylpolysaccharide- based adjuvant mixture. However, the addition of adjuvants to tebuconazole + triadimenol had a negative effect. Of all the adjuvants tested, the nonylphenol ethoxylate and a mixture of mineral oil /surfactant and alkylpolysaccharides gave the highest efficacy with the fungicides, while the mineral oil/surfactant and the alkylpolysaccharides alone were less effective. There was a positive relationship between high concentrations of adjuvants and their effectiveness, but there were some exceptions. The most effective fungicides for control of powdery mildew in wheat were prochloraz, mancozeb + oxadixyl and tebuconazole + triadimenol. There was a linear relationship between the high efficacy of the fungicide and the concentration of adjuvants to control powdery mildew in wheat. The highest concentration of adjuvant (2-0 g litre^?1) gave the highest efficacy for the fungicides.     

Genetic diversity and yield performance among T. Aman rice (Oryza sativa L.) landraces in Barishal region of Bangladesh

Journal of Crop Science and Biotechnology - Understanding genetic diversity of rice helps to improve its yield. Although many landraces of rice are grown in the coastal area of Bangladesh, their...     

Effect of Drought Stress and Different Levels of Nitrogen and Potassium Fertilizers on the Accumulation of Osmolytes and Chlorophyll in Rice (Oryza sativa L.)

Gesunde Pflanzen - Management of plant nutrition using fertilizers is an approach to deal with drought and to increase water productivity in paddies. The aim of this study, therefore, was to...     

Growth characteristics and reproductive output of dwarf mistletoe-infected Juniperus polycarpos in Iran

Dwarf mistletoes are parasitic flowering plants that infect conifers, resulting in substantial loss of growth and mortality. Recently, forest managers in Iran are contemplating whether infection of Juniperus polycarpos C. Koch forests by dwarf mistletoe, Arceuthobium oxycedri （DC.） M. Bieb, influences tree vigor and contributes to insuffieient natural regeneration. The present study aimed at assessing the severity of infection and its impact on growth and reproductive output of./., polycar- pos. Infected and uninfected trees （n =20 each） were selected for assess- ment of diameter, height, crown area, and crown volume as well as quantity and quality of cones and seeds. The severity of infection of trees was determined by Hawksworth＇s 6-class dwarf mistletoe rating （DMR） system. The DMR system revealed that 40% of the infected sample trees were lightly infected （DMR =1-2） and 60% were moderately infected （DMR =3--4）. Growth characteristics did not differ significantly （p 〉 0.05） between infected and uninfected trees. However, moderate infec- tion affected the reproductive output of./. polycarpos by significantly （p 〈0.05） reducing the mean number of cones per unit area of the crown, increasing the number of damaged seeds, and reducing seed size and seedgermination capacity. We conclude that reproductive output of J.. poly- carpos is more sensitive than growth characters to moderate infection by juniper dwarf mistletoe, and this might partly account for poor natural regeneration.     

Characteristics of chemical components in genetic resources of garlic Allium sativum collected from all over the world

The aim of this work was to evaluate garlic diversity based on the production of chemical components in the bulbs and geographical distribution. A total of 103 garlic clones collected from worldwide sources were grown in Yamaguchi, Japan. The chemical contents–S-allyl-l-cysteine sulfoxide (AlCSO), and phenolic content—of garlic collections were determined by HPLC and Folin–Ciocalteu assay, respectively. Quantitative analysis of the chemical content showed wide variations between geographical collection sites. Morphological observation of inflorescence was performed, and clones were divided into four types according to their bolting traits: Type A—bolters, producing mainly florets; Type B—bolters, producing mainly bulbils; Type C—incomplete bolters; and Type D—non-bolters. The appearance frequencies of the bolting types varied depending on the latitude of the collection sites. A comparison of these four different types was carried out based on chemical composition data. Garlic clones that possessed florets showed a tendency for higher amount of AlCSO content than did Type B. Moreover, it was confirmed that as distance increased from high-latitude areas (Central Asia and The Northern Mediterranean), the garlic was more likely to produce bulbils in the inflorescence with lower AlCSO content and higher phenolic content. This research suggested that garlic’s transition of from sexual propagation to asexual (vegetative) propagation and changes in the chemical composition of the bulbs would have occurred in the process of expanding garlic cultivation. In conclusion, garlic seems to have obtained high environmental adaptability with these transitions and changes via artificial selection.