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Biochar, a carbon-rich by-product of organic matter pyrolysis, has a variety of physiochemical properties beside a variety of applications. This review highlights some physical and chemical characteristics of herbaceous, woody, and sewage waste biochar under different pyrolysis conditions, as well as soil and foliar applications of biochar. The controlling role of pyrolysis temperature was the reason for selecting the discussed biochar types in the study. This review concludes that increasing pyrolysis temperature mainly raised the values of some chemical properties of the biochar, such as pH, electrical conductivity (EC), ash content, total phosphorus (TP), and a few values of physical properties like porosity and specific surface area (SSA). On the other hand, yield and total nitrogen (TN) decreased with rising pyrolysis temperature. Among biochar application methods to soil, mixing biochar with soil before planting is one of the best methods of application, and in most cases, biochar reapplication improved soil properties, while foliar application of biochar has positive effects on plant growth and yield parameters, ranging from low rates to the highest ones. [ABSTRACT FROM AUTHOR]

Seasonal progression of common reed (Phragmites australis) growth has been described by leaf area index (LAI), a key variable of crop growth, during two consecutive seasons at the Kis-Balaton wetland (KBW) in Hungary. The key objective of this study was to quantify the morphometric variability of LAI among common reed beds while distinguishing between established plant canopies with standing water (SR) and without water cover (DR). Seasonal mean LAI of plants with unlimited access to water was 3.21 ± 0.36 and 2.66 ± 0.34 for 2014 and 2015, respectively, while that of plants growing without water cover was 1.11 ± 0.22 and 0.89 ± 0.19. Common reed may be more sensitive to the presence or lack of continuous water cover than to variable weather conditions. Weekly LAI curves with two different water supplies as a function of growing degree day (GDD) were conducted to estimate the timing of peak LAI. Modeling the sums of seasonal evapotranspiration (ET) of swamp reed in SR showed only slight increases (56.3 mm and 50.8 mm) in 2014 and 2015, respectively. Total ET showed significant variation between both seasons, with the 2015 sum of ET being almost twice that of 2014. The findings of this study improve our knowledge about the growth of common reed LAI under variable weather conditions and water cover. The response of a plant, including LAI, to varying environments, may illuminate a course of action in wetland conservation programs. In addition, estimates of LAI based on meteorological variables might serve as useful inputs for different ET and growth models. [ABSTRACT FROM AUTHOR]

The results in the issue of local signs of global climate change at Keszthely (Hungary) are summarized and presented in this paper. The meteorological measurements at Keszthely have long history, a more than 140-year-long dataset of monthly amount of precipitation, provided by the University of Pannonia, is available for statistical analysis. The long-time series of precipitation amounts of Keszthely (Hungary) meteorological station was analyzed from the beginning of the observation (1871) until 2014, from the point of view of climate change. Simple climate-statistical analysis has been made in purpose to discover local climate alternations. Linear and exponential trends were fitted, and it was concluded that linear trends in every case had lower relative standard error than exponential trends, so linear changes were interpreted. Despite the fact that significant declining tendency was expected, the annual data does not show any modification in the tendency or variability, but other signs of the decreasing trend can be detected. Significant decreasing tendency was found in spring (-31.5 mm/100 years). Among the monthly sums, the precipitation amount of April (-14 mm/100 years) and October (-23.5 mm/100 years) showed statistically proved decreasing tendency. Variability is increasing significantly in September. These tendencies are unfavorable for the agricultural cultivation of the region. [ABSTRACT FROM AUTHOR]

Hydroxamic acids (HAs) are plant secondary metabolites produced by certain cereals, which have been found to be toxic to pest aphids in artificial diet assays. Previous studies have shown that tetraploid and hexaploid wheat varieties, the leaf tissues of which contained higher levels of these compounds than used in artificial diets, did not reduce aphid settling or fecundity. This current study reports findings on a high HA producing B genome accession of the diploid ancestor of wheat, Aegilops speltoides. We found that this accession does have a negative impact on aphid host selection and substantially reduces nymph production. Whole leaf tissue assays showed very high levels of HAs, well in excess of the toxic level determined in the artificial diet assays. Extraction of the apoplast fluid (AF) from this accession showed that the HA level is much lower than that of the whole tissue, but is still close to the artificial diet toxic level. Furthermore the HA level in the AF increases in response to aphid feeding. These observations could explain why hexaploid wheat remains susceptible to aphids, despite having whole leaf tissue HA levels in excess of the toxic levels determined in artificial diets. [ABSTRACT FROM AUTHOR]

Field crop production must adapt to the challenges generated by the negative consequences of climate change. Yield loss caused by abiotic stresses could be counterbalanced by increasing atmospheric CO2 concentration, but C3 plant species and varieties have significantly different reactions to CO2. To examine the responses of wheat, barley and oat varieties to CO2 enrichment in combination with simulated drought, a model experiment was conducted under controlled environmental conditions. The plants were grown in climate-controlled greenhouse chambers under ambient and enriched (700 ppm and 1000 ppm) CO2 concentrations. Water shortage was induced by discontinuing the irrigation at BBCH stages 21 and 55. Positive CO2 responses were determined in barley, but the CO2-sink ability was low in oats. Reactions of winter wheat to enriched CO2 concentration varied greatly in terms of the yield parameters (spike number and grain yield). The water uptake of all wheat cultivars decreased significantly; however at the same time, water-use efficiency improved under 1000 ppm CO2. Mv Ikva was not susceptible to CO2 fertilization, while no consequent CO2 reactions were observed for Mv Nádor and Mv Nemere. Positive CO2 responses were determined in Mv Kolompos. [ABSTRACT FROM AUTHOR]