Spatial and temporal variability of soil CO2 emission in a sugarcane area under green and slash-and-burn managements

Soil management causes changes in physical, chemical, and biological properties that consequently affect soil CO₂ emission (FCO2). Here, we studied the soil carbon dynamics in areas with sugarcane production in southern Brazil under two different sugarcane management systems: green (G), consisting of mechanized harvesting that produces a large amount of crop residues left on the soil surface, and slash-and-burn (SB), in which the residues are burned before manual harvest, leaving no residues on the soil surface. The study was conducted during the period after harvest in two side-by-side grids installed in adjacent areas, having 60 points each. The aim was to characterize the temporal and spatial variability of FCO2, and its relation to soil temperature and soil moisture, in a red latosol (Oxisol) where G and SB management systems have been recently used. Mean FCO2 emission was 39% higher in the SB plot (2.87 μmol m⁻² s⁻¹) when compared to the G plot (2.06 μmol m⁻² s⁻¹) throughout the 70-day period after harvest. A quadratic equation of emissions versus soil moisture was able to explain 73% and 50% of temporal variability of FCO2 in SB and G, respectively. This seems to relate to the sensitivity of FCO2 to precipitation events, which caused a significant increase in SB emissions but not in G-managed area emissions. FCO2 semivariogram models were mostly exponential in both areas, ranging from 72.6 to 73.8 m and 63.0 to 64.7 m for G and SB, respectively. These results indicate that the G management system results in more homogeneous FCO2 when spatial and temporal variability are considered. The spatial variability analysis of soil temperature and soil moisture indicates that those parameters do not adequately explain the changes in spatial variability of FCO2, but emission maps are clearly more homogeneous after a drought period when no rain has occurred, in both sites.     

Phytotoxicity and genotoxicity of soils from an abandoned uranium mine area

The great number of abandoned uranium mines within the Portuguese territory led to the production of specific legislation establishing the rehabilitation of these areas and the definition of those requiring prior intervention. Cunha Baixa uranium mine (Mangualde, Central Portugal) was one of these areas and a site-specific risk assessment is being carried out for this mine, following European frameworks. In this study the Ames test with soil elutriates, and emergence and growth assays with Lactuca sativa L. and Zea mays L. were performed to assess soil retention and habitat functions. Levels of metals bioaccumulated in plant tissues, grown above soil surface, during the assays, were determined as well. No genotoxic effects were recorded for soil eluates (1:10 and 1:2, m/v) except for site F within the mine area, which is under the effluence of runoffs from the effluent treatment pond. Nevertheless, most of all were highly toxic to Salmonella typhimurium (especially for TA98) strains, used in the assay. The results gathered suggested that during the natural process of soil percolation by rainwater, the leachates yielded are contributing with toxic but no genotoxic metals to underground water resources. Phytotoxicity assays demonstrated that soil habitat function was compromised in almost all the sampling sites selected within the mine area. These results have clearly demonstrated how evaluations based on extractable metal concentrations may underestimate the risks of contaminated soils. Lettuce was the most sensitive species probably due to the great ability of this species in accumulating high concentrations of metals in their aboveground tissues. The highest bioaccumulation factors (BAFs) values were recorded for this species namely for Co (16.5), Cu (28.5), Ba (7.3), Sr (7.2) and Ni (6.1). Copper (9.0) and nickel (3.6) were the main elements bioaccumulated by maize. The dilution of mine soils with a local reference soil has proved to mitigate its toxicity in almost all the sites analysed.     

Enhanced overall resistance to Fusarium seedling blight and Fusarium head blight in transgenic wheat by co-expression of anti-fungal peptides

Introduction of alien genes into wheat has been proposed as a strategy to breed cultivars with improved resistance to Fusarium seedling blight (FSB) and Fusarium head blight (FHB). In this study, we co-transformed different anti-fungal peptides (AFPs) into an elite wheat cultivar Yangmai11. We identified the genetically stable transgenic wheat lines carrying single or multiple genes by PCR, qRT-PCR and Southern blot analyses. Transgenic wheat lines 451 and 513 expressing two AFPs displayed a consistent, significantly improved overall resistance to FSB and FHB, whereas only FHB resistance was observed from other lines. Furthermore, crude proteins extracted from the lines 451 and 513 showed a clear inhibitory activity against F. graminearum in vitro. Taken together, it was essential to properly combine and express AFPs in transgenic wheat in order to obtain an improved overall resistance to Fusarium pathogens.     

Impact of selection for residual feed intake on breeding soundness and reproductive performance of bulls on pasture-based multisire mating

There is concern in the beef industry that selecting bulls for feed efficiency based on residual feed intake (RFI) may have a negative impact on bull reproductive performance and fertility. Here we investigated the impact of selection of bulls for low RFI on breeding soundness evaluation (BSE), reproductive performance, and fertility of bulls under natural service in multisire mating groups on pasture. Of the 412 RFI-tested bulls available, 98 (23.8%) were culled for performance, type, temperament, or other reasons, and 88 (21.4%) were culled for failing BSE, for an overall cull rate of 45.1%. From among the 314 bulls subjected to BSE, 32 (10.2%), 20 (6.4%), and 36 (11.4%) were culled for poor feet and legs, scrotal circumference, and semen quality, respectively. The BSE traits were not different (P > 0.10) between bulls categorized as either inefficient (+RFI) or efficient (-RFI), but the proportion of bulls that failed to meet the 60% minimum sperm motility requirement tended (P = 0.07) to be greater in the -RFI group than in the +RFI group (10.2% vs. 4.4%, respectively). In a subpopulation of 115 bulls, individual progressive sperm motility was greater (P < 0.05) in +RFI (85%) than -RFI (80%) bulls. A multisire natural mating experiment was conducted during 2 consecutive breeding seasons (2006 to 2007 and 2007 to 2008) using 18 +RFI and 18 -RFI bulls. The overall calving rate (calves born/cows exposed) was 72.9%. Mean number of progeny per sire was significantly greater (P < 0.01) in -RFI bulls (18.3) than in +RFI bulls (11.8). Selection for feed efficiency based on RFI appears to have no detrimental impact on reproductive performance and fertility in beef bulls bred in multisire groups on pasture. However, the decreased sperm motility and the greater number of progeny per sire associated with -RFI status need further investigation.     

Clinical and pathological insights into Johne′s disease in buffaloes

Alternative diagnostic tools and interesting epidemiological assumptions were associated with an outbreak of Johne??s disease. In a buffalo herd infected with paratuberculosis, seven clinically affected animals and 21 animals with anti-Mycobacterium avium ELISA reactions were identified. Total herd included 203 buffaloes. Most lesions were comparable to those described in buffaloes and cattle affected by Johne??s disease. Water buffalo behaviors such as communal nursing and allosuckling may be additional risk factors for this disease. Detection of positive Ziehl?CNeelsen staining and anti-M. avium immunolabeling in rectal biopsies from one buffalo with paratuberculosis are highlighted as auxiliary diagnostic tools for Johne??s disease in live animals.     

Effect of addition of coconut water (Cocos nucifera) to the freezing media on post-thaw viability of boar sperm

The prevalence of Leptospirosis in goat herds of the State of Minas Gerais has seldom been studied. The present research had as its objectives: (1) investigate the seroprevalence of Leptospirosis in the county of Uberlandia, MG, (2) verify the Leptospirosis serovars, and (3) identify the risk factors associated with infection on the farms examined. Serum samples from 230 animals in 11 properties were tested using the microscopic agglutination test. An epidemiological examination furnished data for analysis regarding the risk factors. The prevalence of Leptospirosis was found to be 31.3% with variation from 1:100 to 1:800. The most frequent serovars were: Autumnalis (30.30%), Tarassovi (19.20%), Pyrogenes (13.13%), and Icterohaemorrhagiae (11.11%). The ages and races of the animals were among the risk factors found to be significantly correlated (P < 0.05) with infection. At the farm level, the intensity of production, use of salaried workers, and association of other animals were all found to be related with the frequency of Leptospirosis. The results demonstrated that inadequate management was a factor which favored the occurrence of infection in the region of the study.     

Influence of tongue inspection during cysticercosis diagnosis on some behavioral and physiological stress measures in pigs (<Emphasis Type="Italic">Sus scrofa domestica</Emphasis>)

To evaluate the level of stress induced by the tongue inspection method during cysticercosis diagnosis in pigs at 60 and 90 kg, 27 animals were assigned to one of three experimental groups. In the first group (T1), pigs were held with a snout noose. In addition, animals in T2 were subjected to tongue inspection, while in T0, none of the procedures described above were performed. Resistance to be handled and serum cortisol concentration were higher (P < 0.05) than those from T0 in T1 and T2 groups, for 60- and 90-kg pigs. Time to return to the feeder observed the same pattern than previous variables in 60-kg pigs, but T1 and T0 were similar (P > 0.05) for the heavier animals. T2 did not build up a significant amount of stress with respect to T1, where only more (P > 0.05) vocalizations were emitted by 90-kg pigs. It was concluded that the use of snout noose induces major changes in some behavioral and physiological measures of stress in swine, while the opening of the mouth including tongue inspection does not contribute significantly to this effect.     

Distribution of lesions in fetal brains following experimental infection of pregnant sheep with Toxoplasma gondii

Six ovine fetal brains were harvested 33 to 35 days postchallenge from 5 ewes, each of which was given 3000 Toxoplasma gondii oocysts on day 90 of pregnancy. Histopathologic examination of transverse sections taken at 13 levels in the fetal brains revealed the presence of toxoplasmosis-related lesions in all 6 brains. However, lesions were not randomly distributed (P = .007); they were most numerous at the level of the optic tract, the rostral margin of the pons, and 4 mm caudal to the ansate sulcus and were absent in all sections at the level of the caudal cerebellum. Lesion distribution may be due to hemodynamic factors, differences in the expression of endothelial surface receptor molecules at the level of the blood-brain barrier, or the presence of localized permissive/inhibitory factors within the brain. The results have implications for the selection of areas of brain from aborted ovine fetuses to be examined histopathologically for laboratory diagnosis.     

The decreased competition in expanding versus mature juniper woodlands is counteracted by adverse climatic effects on growth

World-wide deforestation is being reversed in Mediterranean continental areas, where abandonment of traditional practises favours the expansion of valuable habitats, like Juniperus thurifera woodlands. We hypothesised that pre-existing trees facilitate establishment in expanding woodlands, whereas in mature woodlands, competition leads to patch disaggregation. We compared the imprint of these processes on growth, demographic and spatial structure of expanding and mature J. thurifera woodlands. We selected plots where we geopositioned, aged and quantified the morphological characteristics of all trees. In the mature woodland, trees arranged in clumps and randomly in the expanding woodland. Competition negatively affected growth, was greater in the mature woodland and led to disaggregation of juvenile clumps. Differences in growth between the mature and the expanding woodland disappeared in climatically unfavourable years, suggesting that adverse climate constrains growth more in expanding than in mature woodlands. We suggest that change in the dispersal agents and a decrease of facilitation underlay differences in spatial patters between the expanding and the mature woodland. Observed effective recruitment in less than 30?years into the expanding woodland evidenced that propagule arrival and sapling survival do not constrain woodland expansion. Furthermore, growth of juveniles established in these new areas is favoured by reduced intra-specific competition. However, we expect growth in expanding woodlands to be negatively impacted by climate change. We conclude that under current global change scenario, conservation of J. thurifera woodlands is favoured by changes in land use, but greater frequency and severity of drier than usual episodes could hamper natural reforestation.