Optimization of Potassium Supply under Osmotic Stress Mitigates Oxidative Damage in Barley.

Potassium (K) is the most abundant cation in plants, playing an important role in osmoregulation. Little is known about the effect of genotypic variation in the tolerance to osmotic stress under different K treatments in barley. In this study, we measured the interactive effects of osmotic stress and K supply on growth and stress responses of two barley cultivars ( L.

Sulfur-enriched leonardite and humic acid soil amendments enhance tolerance to drought and phosphorus deficiency stress in maize (Zea mays L.).

Soil amendments are known to promote several plant growth parameters. In many agro-ecosystems, water scarcity and drought induced phosphorus deficiency limits crop yield significantly. Considering the climate change scenario, drought and related stress factors will be even more severe endangering the global food security.

Effect of biochar origin and soil type on the greenhouse gas emission and the bacterial community structure in N fertilised acidic sandy and alkaline clay soil.

Soil amendment with biochar has received increased attention because of its potential to i) sequester carbon and ii) reduce NO emission when applied to N fertilised soils. To study the effect of biochar origin on greenhouse gas emission in two contrasting soil types, we used a robotized continuous flow incubation system and δC stable isotope approach to compare four biochar types (feed stock: olive mill, corn cob, pistachio shell, cotton stalk) in an alkaline clay soil and two selected biochar types (feed stock: olive mill and corn cob) in an acidic sandy soil. Furthermore, high-throughput sequencing of 16S rRNA genes was performed at the end of the incubation to investigate the effect of different biochars on bacterial community structure in the two different soils.

Quantitative limitations to photosynthesis in K deficient sunflower and their implications on water-use efficiency.

Potassium (K) is crucial for crop growth and is strongly related to stress tolerance and water-use efficiency (WUE). A major physiological effect of K deficiency is the inhibition of net CO assimilation (A) during photosynthesis. Whether this reduction originates from limitations either to photochemical energy conversion or biochemical CO fixation or from a limitation to CO diffusion through stomata and the leaf mesophyll is debated.

Fast responses of metabolites in Vicia faba L. to moderate NaCl stress.

Salt stress impairs global agricultural crop production by reducing vegetative growth and yield. Despite this importance, a number of gaps exist in our knowledge about very early metabolic responses that ensue minutes after plants experience salt stress. Surprisingly, this early phase remains almost as a black box.

The activity of nodules of the supernodulating mutant Mtsunn is not limited by photosynthesis under optimal growth conditions.

Legumes match the nodule number to the N demand of the plant. When a mutation in the regulatory mechanism deprives the plant of that ability, an excessive number of nodules are formed. These mutants show low productivity in the fields, mainly due to the high carbon burden caused through the necessity to supply numerous nodules.

Soil C and N availability determine the priming effect: microbial N mining and stoichiometric decomposition theories.

The increasing input of anthropogenically derived nitrogen (N) to ecosystems raises a crucial question: how does available N modify the decomposer community and thus affects the mineralization of soil organic matter (SOM). Moreover, N input modifies the priming effect (PE), that is, the effect of fresh organics on the microbial decomposition of SOM. We studied the interactive effects of C and N on SOM mineralization (by natural (13) C labelling adding C4 -sucrose or C4 -maize straw to C3 -soil) in relation to microbial growth kinetics and to the activities of five hydrolytic enzymes.

Potassium in agriculture--status and perspectives.

In this review we summarize factors determining the plant availability of soil potassium (K), the role of K in crop yield formation and product quality, and the dependence of crop stress resistance on K nutrition. Average soil reserves of K are generally large, but most of it is not plant-available. Therefore, crops need to be supplied with soluble K fertilizers, the demand of which is expected to increase significantly, particularly in developing regions of the world.

Soil denitrification potential and its influence on N2O reduction and N2O isotopomer ratios.

Rationale: N2O isotopomer ratios may provide a useful tool for studying N2O source processes in soils and may also help estimating N2O reduction to N2. However, remaining uncertainties about different processes and their characteristic isotope effects still hamper its application. We conducted two laboratory incubation experiments (i) to compare the denitrification potential and N2O/(N2O+N2) product ratio of denitrification of various soil types from Northern Germany, and (ii) to investigate the effect of N2O reduction on the intramolecular (15)N distribution of emitted N2O.

Contribution of nitrification and denitrification to nitrous oxide emissions from soils after application of biogas waste and other fertilizers.

The attribution of nitrous oxide (N(2)O) emission to organic and inorganic N fertilizers requires understanding of how these inputs affect the two biological processes, i.e. denitrification and nitrification.

Long-term influence of manure and mineral nitrogen applications on plant and soil 15N and 13C values from the Broadbalk Wheat Experiment.

The Broadbalk Wheat Experiment at Rothamsted Research in the UK provides a unique opportunity to investigate the long-term impacts of environmental change and agronomic practices on plants and soils. We examined the influence of manure and mineral fertiliser applications on temporal trends in the stable N ((15)N) and C ((13)C) isotopes of wheat collected during 1968-1979 and 1996-2005, and of soil collected in 1966 and 2000. The soil delta(15)N values in 1966 and 2000 were higher in manure than the mineral N supplied soil; the latter had similar or higher delta(15)N values than non-fertilised soil.