Building resilience against drought and soil erosion: impact of field water conservation in the drought prone Vertisol areas of northern Ethiopia

Field water conservation practices are a way forward to build resilience against drought through increasing productive green water and crop yield, while reducing runoff (blue water) and soil erosion. A long-term tillage experiment was carried out (2005 to 2011) on a Vertisol to quantify the impact of field water conservation practices on soil moisture, runoff, soil loss and crop yield in a rainfed field in northern Ethiopia. The experimental layout was a randomized complete block design with three replications on permanent plots of 5 m by 19 m. The tillage treatments were (i) derdero+ (DER+) with a furrow and permanent raised bed planting system, 30% standing crop residue retention and no-tillage on top of the bed, (ii) terwah+ planting system (TER+) with ploughing once at sowing, 30% standing crop residue retention and fresh broad beds, and (iii) conventional tillage (CT) with a minimum of three tillage operations and removal of crop residues. The crops grown in rotation were wheat, barley, teff and grass pea. The field conservation practices thus combined indigenous conservation practices (derdero and terwah) with the concepts of conservation agriculture (hence the ‘+’). Data on soil loss, runoff, soil moisture, crop yield and NDVI were collected. Significantly different (p<0.05) mean soil losses of 4.4, 12.5 and 18 t/ha/y were recorded for DER+, TER+ and CT, respectively. Similarly, the mean runoff was 458, 706 and 925 m3/ha/y from treatments with DER+, TER+ and CT, respectively. The average grain yield of wheat over three years was 2.46, 2.02 and 1.61 t/ha for DER+, TER+ and CT, respectively. NDVI records in wheat and grass pea were higher in DER+

An Integrated Approach for the Analysis of Biological Pathways using Mixed Models

Gene class, ontology, or pathway testing analysis has become increasingly popular in microarray data analysis. Such approaches allow the integration of gene annotation databases, such as Gene Ontology and KEGG Pathway, to formally test for subtle but coordinated changes at a system level. Higher power in gene class testing is gained by combining weak signals from a number of individual genes in each pathway. We propose an alternative approach for gene-class testing based on mixed models, a class of statistical models that

Genetic dissection of the relationships between grain yield components by genome-wide association mapping in a collection of tetraploid wheats

Increasing grain yield potential in wheat has been a major target of most breeding programs. Genetic advance has been frequently hindered by negative correlations among yield components that have been often observed in segregant populations and germplasm collections. A tetraploid wheat collection was evaluated in seven environments and genotyped with a 90K SNP assay to identify major and stable quantitative trait loci (QTL) for grain yield per spike (GYS), kernel number per spike (KNS) and thousand-kernel weight (TKW), and to analyse the genetic relationships between the yield components at QTL level. The genome-wide association analysis detected eight, eleven and ten QTL for KNS, TKW and GYS, respectively, significant in at least three environments or two environments and the mean across environments. Most of the QTL for TKW and KNS were found located in different marker intervals, indicating that they are genetically controlled independently by each other. Out of eight KNS QTL, three were associated to significant increases of GYS, while the increased grain number of five additional QTL was completely or partially compensated by decreases in grain weight, thus producing no or reduced effects on GYS. Similarly, four consistent and five suggestive TKW QTL resulted in visible increase of GYS, while seven additional QTL were associated to reduced effects in grain number and no effects on GYS. Our results showed that QTL analysis for detecting TKW or KNS alleles useful for improving grain yield potential should consider the pleiotropic effects of the QTL or the association to other QTLs

Brazilian Consensus on Photoprotection

Brazil is a country of continental dimensions with a large heterogeneity of climates and massive mixing of the population. Almost the entire national territory is located between the Equator and the Tropic of Capricorn, and the Earth axial tilt to the south certainly makes Brazil one of the countries of the world with greater extent of land in proximity to the sun. The Brazilian coastline, where most of its population lives, is more than 8,500 km long. Due to geographic characteristics and cultural trends, Brazilians are among the peoples with the highest annual exposure to the sun. Epidemiological data show a continuing increase in the incidence of nonmelanoma and melanoma skin cancers. Photoprotection can be understood as a set of measures aimed at reducing sun exposure and at preventing the development of acute and chronic actinic damage. Due to the peculiarities of Brazilian territory and culture, it would not be advisable to replicate the concepts of photoprotection from other developed countries, places with completely different climates and populations. Thus the Brazilian Society of Dermatology has developed the Brazilian Consensus on Photoprotection, the first official document on photoprotection developed in Brazil for Brazilians, with recommendations on matters involving photoprotection

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Lawson criterion for ignition exceeded in an inertial fusion experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

What can crop stable isotopes ever do for us? An experimental perspective on using crop carbon stable isotope values for reconstructing water availability in semi-arid and arid environments

This study re-assesses and refines the use of crop carbon stable isotopes (Δ13C) to reconstruct past water availability. Durum wheat, six-row barley, and sorghum were experimentally grown at three crop growing stations in Jordan for up to three years under five different irrigation regimes: 0% (rainfall only), 40%, 80%, 100%, and 120% of the crops’ optimum water requirements. Results show large variation in carbon stable isotopes for crops that received similar amounts of water, either as absolute water input or as percentage of crop requirements. We conclude that C3 crop carbon stable isotope composition can therefore be best interpreted in terms of extremely high values showing an abundance of water versus low values indicating water-stress. Values in between these extremes are problematic and best interpreted in conjunction with other proxies. C4 crop isotopes were not found to be useful for the reconstruction of water availability

Influence of tillage, residue management, and crop rotation on soil microbial biomass and catabolic diversity

The densely populated, intensively cropped subtropical highlands of the world have agricultural sustainability problems from soil erosion and fertility decline. In 1991, the International Maize and Wheat Improvement Center (CIMMYT) initiated a long-term field experiment at its semi-arid highland experiment station in Mexico (2240 masl; 19.318N, 98.508W; Cumulic Phaeozem) to investigate the long-termeffects of tillage/seeding practices, crop rotations, and crop residue management on maize and wheat grown under rainfed conditions. Soil ecology status contributes to agricultural system sustainability, and evaluations were made to determine the effect of different management practices on soil microbial biomass (SMB) (substrate-induced respiration (SIR) and chloroform fumigation incubation (CFI)) and micro-flora physiological and catabolic diversity (BIOLOGTM ecoplate well system). SMB-C (CFI, SIR) was significantly and respectively 1.2 and 1.3 times higher for residue retention (average 387mg C kg1 dry soil and 515 mg C kg1 dry soil, respectively) compared to residue removal. SMB-C (CFI) was significantly higher for wheat (369mg C kg1 dry soil) compared to maize (319mg C kg1 dry soil). SMB-N (CFI) was significantly 1.3 times higher for residue retention (average 28mg N kg1 dry soil) compared to residue removal. The average well color development (AWCD) obtained by the BIOLOGTM ecoplate essay indicated there were large differences in the catabolic capability of soil microbial communities after 15 years of contrasting management practices. While maize and wheat rotation under conventional tillage with residue retention showed a significantly higher overall AWCD value compared to the other treatments, AWCD ofmaize with zero tillage and residue removal was significantly lower than in the other treatments. AWCD was significantly higher for residue retention compared to residue removal and for wheat as compared to maize. For maize, the management practices were divided into two groups; zero tillage with residue removal was separate from all other treatments. For wheat, conventional tillage was separate from all zero tillage treatments. This study suggests that in the target area, a cropping system that includes zero tillage, crop rotation, and crop residue retention can increase overall biomass and micro-flora activity and diversity compared with common farming practices. In the long term, zero tillage combined with residue retention creates conditions favourable for the development of antagonists and predators, and fosters a new ecological stability. Zero tillage without residue retention is an unsustainable practice that leads to poor soil health in the long run.status: publishe