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In this study, productivity rate and operation cost of farm tractor were evaluated in a mountainous natural forest. Data for the study came from a detailed time study in the Research and Educational Forest of Tarbiat Modares University (REFTMU) and was used to develop a multiple linear regression model to predict the skidding cycle time. The results showed that effective independent variables of skidding time were skidding distance and slope of skid trail (P = 0.01). Average productivity rate ranged from 2.43 to 2.60 m².h^-1. Total time and effective time, respectively. Total cost of the system was 10.24 USD.h^-1 whereas 4.58% of the cost of skidding resulted from personal delay. The cost and productivity resulting from this study emphasized the importance for foresters to consider a farm tractor when designing skidding operations in young stands or prescribing a combination of two machines in mature stands.

This paper presents research results of the performance of HSM-904 grapple skidder using a full tree harvesting method in a non-native aspen Populus deltoides plantation in even terrain conditions in Shafaroud, Northern Iran. Patch cutting as a silvicultural method was used in the plantation (2,000 ha). To evaluate the newly introduced machine to a ground skidding system in the aspen plantation and the possibility to increase the production rate, an empirical time study was conducted. The elements of the skidding work phase were identified and 58 cycles were recorded for the study. The models for effective time consumption, total productivity and work phase models are calculated. The average load per cycle was 2.2 m³, the average one-way skidding distance was 253 m. The average travel speed of unloaded skidder was 5.53 km.h^-1 and the average speed of loaded skidder was lower than the speed of the unloaded one by 2.94 km.h^-1. The average output in the study was 7.1 m³ per effective hour and the unit cost was 13.9 USD.m^-3.

Phytophthora alni is responsible for a devastating disease in alder and changes in the environment of riparian and alder carr ecosystems. One of the main approaches to solve this problem is to find naturally resistant genotypes using a series of artificial inoculation experiments, to preserve and use them in programmes for resistance breeding. However, the results of artificial inoculation experiments (screening for natural resistance) can be affected by several factors. The potential effect of the social status of the host, the presence of naturally occurring P. alni infections, the season and the size of the sections of branches used were studied in a series of infection experiments. It was found out that the development of lesions was significantly affected by the year season (the largest lesions were found in summer) and by the presence of naturally occurring P. alni infections in the sampled trees (the lesions were five times larger in healthy trees and trees recovered from natural P. alni infections compared to trees with active disease development).

Earlier breeders used phenotypic selection based on morphological characteristics to improve tree varieties. These selections often take many cycles of breeding and backcrossing in order to place desired characteristics. But today the knowledge has paved the way for a much deeper understanding of the mechanics of cell biology and the hereditary process itself. Breeders are presented with numerous possibilities of altering the behaviour of existing varieties. Linkage between molecular markers can be translated to genetic linkage maps, which have become an important tool in plant genetics. They may choose to use marker-assisted approaches in order to facilitate the selection of favourable combinations of genes that occur naturally within a tree species.

The pine stand in the Havraní Skála locality in the Bohemian Switzerland National Park was affected by an extensive mixed-severity wildfire in summer 2006. The fire severity, fire type and fire extent were assessed by various fire severity measures collected in the field (mean bole char height on stems on sample plots, content of oxidizable C and total N at a soil depth of 0-5 cm), as well as by classification and filtering of green canopy cover from time series of aerial photographs acquired before the fire (2005), soon after the fire (2006) and one year after the fire (2007). The specific image analyses made it possible to uncover the spatial and temporal pattern of the stand defoliation. The central part of the site was mainly affected by the crown fire and thus defoliated substantially right during the fire. On the contrary, the peripheral part of the site was mostly affected by low-severity ground fire and therefore defoliated progressively one year later. All the fire severity measures used were well related.

The research was aimed to estimate above- and below-ground carbon stock in Tankawati natural hill forest of Bangladesh. A systematic sampling method was used to identify each sampling point through Global Positioning System (GPS). Loss on ignition and wet oxidation method were used to estimate biomass and soil carbon stock, respectively. Results revealed that the total carbon stock of the forest was 283.80 t.ha^-1 whereas trees produce 110.94 t.ha^-1, undergrowth (shrubs, herbs and grass) 0.50 t.ha^-1, litter fall 4.21 t.ha^-1 and soil 168.15 t.ha^-1 (up to 1m depth). The forest in the study area is a reservoir of carbon, as it has a good capacity to stock carbon from the atmosphere. To realize the forest sector potentiality inBangladesh, the carbon sequestration should be integrated with the Clean Development Mechanism (CDM) carbon trading system of the Kyoto Protocol.

This paper contains the information about some principles of sustainable forestry which are still relevant in the world. In 2002, Lithuania started research on the nutrient balance in forest ecosystems when the forest fuel is harvested. The consequences of the intensive forest fuel harvesting on the forest ecosystem were analysed. At the same time, the experiment on the compensatory wood ash fertilizing was established in Lithuania. After the initial calculations, having the experimental data, the Ministry of Environment of the Republic of Lithuania has initiated the preparation of the Recommendations for compensating wood ash fertilization in the forests. This review briefly systematizes and analyses the main results of the related research and some ideas for the future studies are also presented.

The Bruks mobile chipper was tested for chipping extracted non-merchantable stemwood at the roadside in Pine plantation in Victoria. The elemental time study method was used to evaluate the system productivity. The productivity, cost, biomass yield, remaining slash, chip quality (size classification and energy content), and fuel and energy consumption were analysed. Chipping extracted small logs at the roadside yielded a productivity of 43.88 GMt.PMH₀^-1 (19.4 BDT.PMH₀^-1). The average cost was about 16.96 USD.GMt^-1 (38.36 USD.BDT^-1).

The continued use of waste water for irrigation of agricultural fields in Egypt may lead to accumulation of heavy metals in soils and adverse effects on soil-living communities. We investigated responses of oribatid communities to heavy metal contamination in mango plantations irrigated by the Ismailia canal in the Suez region. Mean concentrations of heavy metals determined in irrigation water were considerably above the recommended levels. Concentrations of metals in agricultural soil were however below the permissible levels. A comparison with concentrations of a typical uncontaminated soil in this area revealed that the Ismailia water canal used for irrigation of agricultural land has elevated levels of heavy metals. The results of our ecological survey showed that the abundance and structure of the soil oribatid communities were not influenced by levels of heavy metals in the soil. We also showed that the diversity index can be a valuable tool for assessing the possible impact of pollutants on different species of oribatid mites. The oribatid species appeared to be accumulating different amounts of heavy metals when characterised by their bioconcentration factors. Most species were poor zinc accumulators. The accumulation of heavy metals in the body of oribatids was not strictly determined by their body size or by the trophic level. In conclusion, our study showed that mango plantations impacted by waste water from the Ismailia canal are accumulating heavy metals in their soils above the background concentrations, but ecological effects on soil-living communities are not apparent yet.

The psyllid Acizzia jamatonica (Kuwayama, 1908), an introduced pest of the ornamental tree Albizia julibrissin Durazz., was found for the first time in Slovakia and Greece. In both countries it occurs in large numbers and reduces the aesthetic qualities as well as the health of the host plant.

Gloriosa superba is a medicinal plant severely infested with soil-borne Macrophomina phaseolina (Tassi) Goid. Under in vitro conditions a commercial formulation of Trichoderma viride and Pseudomonas fluorescens inhibited the mycelial growth of M. phaseolina isolates. Among the oil cake, mahua cake at 10% completely inhibited the mycelial growth of the M. phaseolina isolates. Under field conditions both the soil and foliar application of biocontrol agents is attributed to the healthy growth of G. superba crops by controlling the tuber rot disease and ultimately boosting the colchicine content.

Sheath rot of rice and leaf blight of wheat caused by Pseudomonas syringae pv. syringae are the important bacterial pathogens of rice and wheat in Iran. The randomly amplified polymorphic DNA (RAPD) method was used to investigate the genetic diversity of 60 strains of P. s. pv. syringae obtained from rice and wheat in different growth stages. Cluster analysis by UPGMA method showed that strains were grouped into two clusters. The AMOVA analysis indicated that about 18% of the total genetic variation existed between two populations of rice and wheat, which showed the lack of host specialization in P. s. pv. syringae strains among rice and wheat. We confirmed that high genetic heterogeneity existed in the P. s. pv. syringae strains which are detectable by RAPD analysis, and that molecular and statistical analysis of RAPD fragments can be used both to distinguish between strains and to determine relatedness between them.

The efficiency of border rows to prevent the adventitious presence of GM maize in non-GM maize plots was evaluated as well as the effect of the MON 810 maize of the yield and self-protection against the European corn borer. The GM maize MON 810 event was drilled at 3 locations over the Slovakia and the grain samples were collected from the neighbouring conventional maize fields. The data obtained by Real-Time PCR indicate that coexistence between GM and conventional maize is feasible and the isolation distance of 200 m (respectively 100 border rows of conventional maize) separates GM maize from the conventional one more than sufficiently. The effective isolation distance is 3-4 times greater than the actually needed. The MON 810 revealed also the highest yield and the best self-protection against European corn borer in both growing seasons with different climatic conditions.

Commercialisation of Biotech/GM (Biotech) crops started in 1995. Not only field crops, but also horticultural transgenic crops are under development and are beginning to be commercialised. Genetic engineering has the potential to revolutionise fruit tree breeding. The development of transgenic fruit cultivars is in progress. Over the past 20 years an international public sector research team has collaborated in the development of HoneySweet plum which is highly resistant to Plum pox virus (PPV) the most devastating disease of plums and other stone fruits. HoneySweet was deregulated in the USA in 2010. HoneySweet (aka C5) has been evaluated for eleven years (2002-2012) in a regulated field trial in the CzechRepublic for the resistance to PPV, Prune dwarf virus (PDV), and Apple chlorotic leaf spot virus (ACLSV), all of them being serious diseases of plum. Even under the high and permanent infection pressure produced through grafting, PPV has only been detected in HoneySweet trees in several leaves and fruits situated close to the point of inoculum grafting. The lack of infection spread in HoneySweet demonstrates its high level of PPV resistance. Co-infections of PPV with PDV and/or ACLSV had practically no influence on the quantity and quality of HoneySweet fruit which are large, sweet, and of a high eating quality. In many respects, they are superior to the fruits of the well-known cultivar Stanley. Many fruit growers and fruit tree nurseries in the CzechRepublic are supportive of the deregulation of HoneySweet plum to help improve the plum production and control the spread of PPV.

Little is known about the effects of air-drying and freezing on the transformation of phosphorus (P) fractions in soils. It is important that the way in which soils respond to such perturbations is better understood as there are implications for both P availability and loss to surface waters from soils. In this study, the effects of air-drying and freezing were investigated using two soils, one being a forest soil (FS) high in organic matter and the other being a sterile soil (SS) low in organic matter. Soil P was fractionated using a modified Hedley fractionation method to examine the changes of phosphorus fractions induced by air-drying and freezing. Generally, there were no significant differences of total phosphorus among the three treatments (CV% < 10%). Compared with field moist soils, freezing the soil evoked few changes on phosphorus fractions except that the resin-P increased in FS soil. On the contrary, air-drying significantly changed the distribution of phosphors fractions for both soils: increased the labile-P (especially resin-P) and organic-P (NaHCO₃-Po, NaOH-Po and Con.HCl-Po) at the expense of NaOH-Pi and occlude-P (Dil.HCl-P and Con.HCl-Pi). Resin-P significantly increased by 31% for SS soil and by 121% for FS soil upon air-drying. The effect of air-drying seemed to be more pronounced in the FS soil with high organic matter content. These results indicated that drying seem to drive the P transformation form occlude-P to labile-P and organic-P and accelerated the weathering of stable P pool. This potentially could be significant for soil P supply to plants and P losses from soils to surface waters under changing patterns of rainfall and temperature as predicted by some climate change scenarios.

Grazing-induced variations in vegetation may either accelerate or reduce soil carbon storage through changes in litter quantity and quality. Here, a three-year field study (2005-2007) was conducted in Tibetan alpine meadow to address the responses of surface soil (0-15 cm) organic carbon (SOC) storage in the plant growing season (from May to September) to varying grazing intensity (represented by the residual aboveground biomass, with G₀, G₁, G₂, and G₃ standing for 100%, 66%, 55%, and 30% biomass residual, respectively), and to explore whether grazing-induced vegetation changes depress or facilitate SOC storage. Our results showed that: (i) Higher grazing intensity resulted in lower biomass of grasses and sedges, lower root biomass, and in a change in plant community composition from palatable grasses and sedges to less palatable forbs. (ii) Increased grazing reduced the SOC content and storage with only G₃ showing an SOC loss during the plant growing season. (iii) Soil organic carbon storage exhibited a highly positive correlation with the residual aboveground biomass and root biomass. Our results imply that a grazing-induced reduction in plant biomass productivity and changes in species composition would depress soil carbon storage, and that an increase in grazing pressure can lead to a gradual change of alpine meadow soils from being 'carbon sinks' to become 'carbon sources'.

The aim of the experiment was to test the capacity of NO to reverse harmfull effects of nickel on bean (Phaseolus vulgaris L.) seedlings. Bean seedlings were grown on culture medium and treated with NO-donor - sodium nitroprusside (0.3 mmol/L) and Ni (0.2 mmol/L NiCl₂). After 4 days, the parameters of antioxidative response were determined in roots and leaves, as well as the concentrations of essential cations and Ni. In the presence of Ni alone, soluble protein, proline and superoxide-dismutase activity were increased, while peroxidase and especially catalase activities were supressed. Also, Ni induced a depletion of K, Ca, Mg, Mn and Zn, while the contents of Cu and Fe in the roots were increased. In the presence of NO, Ni-induced stimulation of superoxide-dismutase activity, soluble protein and proline accumulations was decreased, while the inhibition of peroxidase and catalase activities was eliminated. Calcium and Zn concentrations were increased by Ni in NO-treated seedlings, suggesting specific activation of the uptake of these elements as part of the protective processes regulated by NO. However, NO had no effect on the impact of Ni on K, Cu, Fe, and Mn concentrations. In conclusion, exogenous NO efficiently attenuates oxidative stress in bean, but does not prevent Ni-induced ion leakage.

Opium poppy (Papaver somniferum L.) is currently an important agricultural commodity, with the product being used in the food industry (seed) as well as in the pharmaceutical industry (morphine and other alkaloids). Intensive production of poppy leads to a specific direction of breeding with the aim to obtain highly productive cultivars of the so-called food industry or industrial type. The paper evaluates 57 genetic resources (mostly cultivars), comparing the groups of values representing the indicators of production-significant morphologic and agricultural characters (capsule size; morphine content in poppy straw; weight of dry, empty capsule) and content of morphine in the poppy straw, in relation to the ideotype of poppy, which in these indicators represents 100% of the value. On average lower values in the above indicators were achieved by cultivars with white-coloured seed, including morphine content; concrete data are specified in three cultivars with morphine content in the poppy straw above 0.40%. In blue-seed to grey-seed cultivars, except for the high-morphine cultivar Buddha (1.85% of morphine), we found only six materials with a minimum morphine content of 0.8% in the poppy straw (maximum of 0.92%). These genetic resources also achieved very good values in the morphological indicator and average value in the economic indicator. The results will be used in the selection and classification of suitable genetic resources of poppy in breeding of industrial forms.

The experiment was carried out to observe the influence of the CULTAN method (controlled uptake long term ammonium nutrition) on grain yield and yield formation of spring barley cultivar Jersey. In four-year small-plot experiment under conditions of the Czech Republic, two methods of nitrogen fertilization were used: conventional surface fertilization and local fertilizer injection rich in ammonium into soil during vegetation at BBCH 29-30 stages. Furthermore, the impact of sulphur amendment in fertilizer and increased dose of fertilizer were observed. Basic dose of nitrogen was 80 kg N/ha, increased dose 130 kg N/ha. At CULTAN treatment, same or significantly higher grain yields were obtained compared to conventional nitrogen fertilization. Grain yield at CULTAN fertilization is formed mainly on the main stem because of reduced tillering; it has the impact on significantly higher percentage of grain retained on 2.5 mm sieve. A tendency to lower protein content in grain was recorded at local injection of fertilizer compared to conventional fertilization. CULTAN-treated plants showed a lesser dependency of qualitative parameters on fertilizer dose and sulphur amendment in fertilizer. A positive influence of the CULTAN method on yield and quality of grain was observed mainly at the less fertile site.

Soil arsenic (As) levels are particularly high in parts of China, where wheat and rape are widely grown. Understanding the effects of As concentration on the growth of these two major crops is of significance for food production and security in China. A pot experiment was carried out to study the uptake of As and phosphorus (P), and the soil As bioavailability at different growth stages of wheat and rape. The results indicated that winter wheat was much more sensitive to As stress than rape. Wheat yields were elevated at low rates of As addition (< 60 mg/kg) but reduced at high rates of As concentrations (80-100 mg/kg); while the growth of rape hadn't showed significant responses to As addition. Phosphorus concentrations in wheat at jointing and ear sprouting stages increased with increasing soil As concentrations, and these increases were assumed to contribute a lot to enhanced growth of wheat at low As treatments. Arsenic did not significantly affect P concentrations in rape either. The highest As concentrations in wheat shoot and rape leaf were 8.31 and 3.63 mg/kg, respectively. Arsenic concentrations in wheat and rape grains did not exceed the maximum permissible limit for food stuffs of 1.0 mg/kg. When soil As concentration was less than 60 mg/kg, both wheat and rape could grow satisfactorily without adverse effects; when soil As concentration was 80-100 mg/kg, rape was more suitable to be planted than wheat.

A field experiment was conducted to illustrate the different degree and dynamics of microbial community structure and function in the rhizosphere across four growing stages (before plantation and three growth stages) using a combination of biochemical (enzyme assay and microbial biomass carbon) and molecular approaches of qPCR and PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis). Rice plant cultivation promoted higher enzyme activities (invertase and urease), microbial biomass carbon (C_mic), bacterial (16S rRNA) and fungal (ITS rRNA) genes abundances in the rhizosphere compared to unplanted soil. Principal component analyses of PCR-DGGE profile also revealed that structures of bacterial and fungal communities of rice planted soil were well distinct from unplanted soil. Moreover, enzyme activities showed a significant positive correlation with the total microbial biomass in the rhizosphere throughout growth stages of rice plant. Relative fungal: bacterial ratios were significantly higher in rice planted soil compared to unplanted soil, suggesting rice plantation enhanced the fungal community in the rice rhizosphere environment. These results further suggest a significant linkage between the microbial community dynamics and function in the rhizosphere associated with rice plant over time.

This study was undertaken in order to test whether the development of nodule density over the vegetation period is different in lucerne stands grown for 1, 2 or 3 years continuously. For rapidly assessing nodule density in the field, a modified profile wall method was applied. Nodules were counted on a vertical profile wall, after spraying away a 2 cm layer of soil. For validating this method nodule density was determined on roots washed from monolith samples. Field data indicate that there is a shift of nodulation towards deeper soil layers with increasing maturity of lucerne stands. In 1-year lucerne nodulation was limited virtually to the top 15 cm of soil. In the 15-30 cm soil layer and in the subsoil (30-80 cm), nodule density increased with the cropping duration (1 year < 2 years < 3 years). Temporal decreases in nodule density during the vegetation period associated with dry spells were more pronounced for 2-years as compared with 3-years lucerne.

Non-destructive and rapid monitoring methods for crude protein content (CPC) in rice grain are of significance in nitrogen diagnosis and grain quality monitoring, and in enhancing nutritional management and use efficiency. In this study, CPC and canopy spectra in rice were measured based on rice field experiment. Key spectral bands were selected by principal component analysis (PCA) method, and the predicted models were built by multiple linear regressions (MLR), artificial neural network (ANN) and partial least squares regression (PLSR). The results showed that there is a significant correlation between CPC content and key spectral bands. The results of prediction for the three models were in order of PLSR > ANN > MLR with correlation values of 0.96, 0.92 and 0.90, respectively, for the validation data. Therefore, it is implied that CPC in rice (grain quality) could be estimated by canopy spectral data.

Soil quality and fertility are associated with its productivity, and this in turn is connected to the soil biological activity. To study these effects, well designed long-term field experiments that provide comprehensive data sets are the most applicable. Four treatments (tillage methods) were set up: (1) conventional tillage (CT); (2) no tillage (NT); (3) minimum tillage + straw (MTS), and (4) no tillage + mulch (NTM). Our objective was to assess the relationships between soil microbial characteristics and winter wheat yields under these different techniques of conservation tillage within a field experiment, originally established in 1995. The differences in average grain yields over time period 2002-2009 between the variants were not statistically significant. Organic carbon in the topsoil was higher in plots with conservation tillage (NT, MTS, and NTM), than in the conventional tillage plots. There was a statistically significant correlation (P ≤ 0.01) between the grain yields and organic C content in topsoil.

Relatively little is known about potassium leaching losses following harvest of silage maize. While direct negative impacts on the environment are unlikely, losses of K with leaching need to be known for accurate balancing, especially on coarse textured soils, where K can be a critical element. In a four-year field experiment the effects of fertilizer forms (inorganic, cattle slurry and pig slurry) and four levels of N input (0, 80, 160, 240 kg N/ha) with corresponding amounts of K on the nutrient balances and leaching of K from silage maize grown on a sandy soil were investigated using suction cups. After four years, surplus of K from cattle slurry led to higher lactate-soluble K in the topsoil. Potassium leaching differed between years with different amounts of rainfall during winter. Annual leaching losses of K increased with N and K input and amounted to 38 kg K/ha, while fertilizer form had no significant effect. Losses of K increased with increasing N leaching (R² = 0.69). We conclude that in maize production on coarse textured soils and under conditions of high N leaching (86-152 kg N/ha), K leaching can be large (6-84 kg K/ha) and constitutes a relevant part of K balances (-84 to +127 kg K/ha).