Assessing long term effects of compost fertilization on soil fertility and nitrogen mineralization rate

Background

Fertilization with organic waste compost can close the nutrient cycles between urban and rural environments. However, its effect on yield and soil fertility must be investigated.

Aim

This study investigated the long-term effect of compost on soil nutrient and potentially toxic elements (PTEs) concentration, nutrient budgets, and nitrogen (N) mineralization and efficiency.

Methods

After 21 years of annual compost application (100/400 kg N ha^–1 year^–1 [100BC/400BC]) alone and combined with mineral fertilization, soil was analyzed for pH, organic carbon (SOC), nutrient (total N and P, N_min, extractable CAL-P, CAL-K, and Mg), and PTE (Cu, Ni, Zn) concentrations. Yields were recorded and nutrient/PTE budgets and apparent net mineralization (ANM, only 2019) were calculated.

Results

N efficiency was the highest in maize and for mineral fertilization. Compost application led to lower N efficiencies, but increased ANM, SOC, pH, and soil N, and surpluses of N, P, and all PTEs. Higher PTE concentrations were only found in 400BC for Cu. Nutrient budgets correlated with soil nutrient concentration. A surplus of 16.1 kg P ha^–1 year^–1 and 19.5 kg K ha^–1 year^–1 resulted in 1 mg kg^–1 increase in CAL-P and CAL-K over 21 years.

Conclusion

Compost application supplies nutrients to crops with a minor risk of soil-accumulation of PTEs. However, the nutrient stoichiometry provided by compost does not match crop offtakes causing imbalances. Synchronization of compost N mineralization and plant N demand does not match and limits the yield effect. In winter wheat only 65–70% of N mineralization occurred during the growth period.     

Immunochemical analyses of serum antibodies from pig herds in a Salmonella non-endemic region.

In a large comparative survey of Danish and Swedish slaughter pig herds performed prior to this work, it was unexpectedly found that some Swedish herds harbored seropositive pigs. Serum samples from the Swedish herds had moderate responses in the Salmonella mix-ELISA (detecting serogroup B and C1 infections) compared to the Danish herds classifying some of them as seropositive using a cut-off value at 40 OD%. In Sweden, extensive Salmonella control is carried out by bacteriological screening of feces and lymph nodes, and the overall prevalence has been proven to be below 0.1%. The serological positive results were therefore unexpected; hence the reactivities of the Swedish sera were studied by a number of immunochemical analyses (Western blot, indirect ELISA, inhibition ELISA, avidity ELISA) and compared to sera from Danish pig herds with verified Salmonella infections ("the reference sera").In Western blot, the Swedish sera had high binding reactivities against Salmonella Typhimurium LPS of different molecular weights, and gave binding patterns similar to that of the reference sera. Pre-incubation with free S. Typhimurium LPS or PS (the polysaccharide part of LPS) was able to inhibit the reactivity of the Swedish sera in the mix-ELISA. Reactivities against other related bacterial LPS such as Citrobacter freundii LPS and Yersinia enterocolitica O:3 LPS were observed in the Swedish sera, but these LPS antigens were unable to inhibit the reactivities in the mix-ELISA as efficiently as S. Typhimurium LPS. Furthermore, the Swedish sera did not bind Salmonella LPS of another serogroup (S. Meleagridis LPS, serogroup E1) or rough Salmonella LPS, both lacking the specific O-antigenic parts of S. Typhimurium LPS. The avidity of the Swedish sera was much lower than the avidity of the reference sera, which could indicate the presence of transient low-dose infections or stimulation by inactivated bacteria in feed. The results obtained in this investigation strongly indicate that the Swedish sera contain antibodies directed against the O-antigenic part of LPS from S. Typhimurium or possibly on as yet unknown bacterium.     

Streptococcus equi subsp. zooepidemicus isolates from equine infectious endometritis belong to a distinct genetic group

Streptococcus equi subsp. zooepidemicus is the pathogen most commonly isolated from the uterus of mares. S. zooepidemicus is an opportunistic pathogen and part of the resident flora in the caudal reproductive tract. The aim of this study was to investigate whether a genotypically distinct subpopulation of S. zooepidemicus is associated with endometritis in the mare, by genotyping and comparing uterine S. zooepidemicus strains with isolates from the vagina and clitoral fossa. Mares with (n = 18) or without (n = 11) clinical symptoms of endometritis were included. Uterine samples were obtained using a guarded endometrial biopsy punch, whereas a swab was used to recover samples from the cranial vagina and the clitoral fossa. If S. zooepidemicus was present, up to three colonies were selected from each anatomical location (max. 9 isolates per mare). Bacterial isolates were characterized by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). S. zooepidemicus was isolated from the endometrium of 12 mares. A total of 88 isolates were analyzed by PFGE: 31 from the endometrium, 26 from the cranial vagina and 31 isolates from the clitoral fossa. For MLST 21 isolates were chosen. Results demonstrated a higher genetic similarity of the isolates obtained from infectious endometritis compared to isolates obtained from the caudal reproductive tract. In conclusion, we demonstrate for the first time that a genetically distinct group of S. zooepidemicus is associated with infectious endometritis in the mare.     

Utility of serum cystatin C as a clinical measure of renal function in dogs

A human kit for cystatin C determination was evaluated for use with canine sera. A reference range was also established. The association between cystatin C and glomerular filtration rate (GFR) was evaluated in 60 dogs with various diseases, by using exogenous creatinine plasma clearance (ECPC) as a measure of GFR. The correlation between cystatin C and ECPC (correlation coefficient [r] = -0.630; P<0.001) was stronger than the correlation between serum creatinine and ECPC (r = -0.572; P<0.001). Nonrenal diseases (e.g., neoplasia, infection) did not influence serum cystatin C concentration. Test sensitivity was significantly better (P<0.001) for cystatin C (76%) than for creatinine (65%). Specificities for the two tests were 87% and 91%, respectively.     

Use of albumin quotient and IgG index to differentiate blood- vs brain-derived proteins in the cerebrospinal fluid of cats with feline infectious peritonitis

BACKGROUND: Inflammation of the central nervous system (CNS) is a frequent condition in cats but etiology often remains unsolved. Routine cerebrospinal fluid (CSF) analysis can be extended through the calculation of the albumin quotient (Q(alb)), a marker of the integrity of the blood-brain barrier (BBB), and IgG index, an estimate of intrathecal IgG synthesis. OBJECTIVES: The purpose of this study was to validate nephelometric methods for CSF protein analysis, and to use the Q(alb) and IgG index to discriminate blood- and brain-derived immunoglobulin fractions in cats with feline infectious peritonitis (FIP). METHODS: Cats presented to our clinic between 2001 and 2005 were included in the study based on clinical and laboratory data and histopathologic findings at necropsy. Cats were grouped as having nonneurologic disease (controls; n=37), brain tumors (n=8), FIP involving the CNS (n=12), and extraneural FIP (n=12). CSF-total protein (TP) was measured and albumin and IgG concentrations were measured in paired CSF/serum samples; Q(alb) and IgG index were calculated. Intraassay and interassay precision of the nephelometric assays were determined using pooled samples. RESULTS: Coefficients of variation for the nephelometric assays ranged from 2.7% to 7.2%. In control cats, CSF-TP concentration ranged from 0.06 to 0.36 g/L, Q(alb) ranged from 0.6 to 5.7 x 10(-3), and IgG index ranged from 0.3 to 0.6. Q(alb) and IgG index were significantly higher in cats with brain tumors and cats with CNS-FIP compared with other groups. Compared with control cats, pleocytosis was evident in 8 of 12 (67%) cats and CSF-TP was increased in 3 of 12 (25%) cats with CNS-FIP. CONCLUSION: Nephelometry is a reliable method for measurement of CSF protein, albumin, and IgG in cats. The Q(alb) and IgG index did not identify a CSF protein pattern specific for BBB dysfunction or intrathecal IgG synthesis in cats with CNS-FIP.     

Macroalgal meadow habitats support fish and fisheries in diverse tropical seascapes

Canopy‐forming macroalgae can construct extensive meadow habitats in tropical seascapes occupied by fishes that span a diversity of taxa, life‐history stages and ecological roles. Our synthesis assessed whether these tropical macroalgal habitats have unique fish assemblages, provide fish nurseries and support local fisheries. We also applied a meta‐analysis of independent surveys across 23 tropical reef locations in 11 countries to examine how macroalgal canopy condition is related to the abundance of macroalgal‐associated fishes. Over 627 fish species were documented in tropical macroalgal meadows, with 218 of these taxa exhibiting higher local abundance within this habitat (cf. nearby coral reef) during at least one life‐history stage. Major overlap (40%–43%) in local fish species richness among macroalgal and seagrass or coral reef habitats suggest macroalgal meadows may provide an important habitat refuge. Moreover, the prominence of juvenile fishes suggests macroalgal meadows facilitate the triphasic life cycle of many fishes occupying diverse tropical seascapes. Correlations between macroalgal canopy structure and juvenile abundance suggests macroalgal habitat condition can influence levels of replenishment in tropical fish populations, including the majority of macroalgal‐associated fishes that are targeted by commercial, subsistence or recreational fisheries. While many macroalgal‐associated fishery species are of minor commercial value, their local importance for food and livelihood security can be substantial (e.g. up to 60% of landings in Kenyan reef fisheries). Given that macroalgal canopy condition can vary substantially with sea temperature, there is a high likelihood that climate change will impact macroalgal‐associated fish and fisheries.     

Does ‘race to fish’ behaviour emerge in an individual transferable quota fishery when the total allowable catch becomes non‐binding?

Successful individual transferable quota (ITQ) management requires a binding (constraining) total allowable catch (TAC). A non‐binding TAC may result in a shift back towards open access conditions, where fishers increasingly compete (‘race’) to catch their share of the total harvest. This process was examined by comparing fishing fleet behaviour and profitability in the Tasmanian southern rock lobster (Jasus edwardsii) fishery (TSRLF), Australia. Between 2008 and 2010, the TSRLF had a non‐binding TAC and effectively reverted to a regulated, limited‐entry fishery. Fishers' uncertainty about future profitability and their ability to take their allocated catch weakened the security characteristic of the ITQ allocation. The low quota lease price contributed to an increase in fleet capacity, while the more limited reduction in quota asset value proved an investment barrier, hindering the autonomous adjustment of quota towards the most efficient fishers. In the TSRLF, catch rates vary more than beach price and are therefore more important for determining daily revenue (i.e., price x catch rate) than market price. Consequently, fishers concentrated effort during times of higher catch rates rather than high market demand. This increased rent dissipation as fishers engaged in competitive race to fish to be the first to exploit the stock and obtain higher catch rates. The history of this fishery emphasizes the need for a constraining TAC in all ITQ fisheries, not only for stock management, but also to manage the security of the ITQ allocation and prevent unanticipated and undesirable changes in fisher behaviour and fishery profitability.     

Pericardial effusion in a cat with feline infectious peritonitis

This case report describes the disease progression of a male cat with pericardial effusion. Clinical signs (dyspnea, lethargy, and weakness) started very acutely. The initial laboratory profile showed only an increase in alanine aminotransferase enzyme activity. Diagnostic imaging revealed pericardial effusion. Effusion analysis showed a Rivalta-positive, modified transudate. Detection of feline coronavirus antigen in macrophages was negative. General condition and laboratory parameters dramatically worsened within seven days. Therefore, the owners decided to euthanize the cat. Even if effusion variables are macroscopically and microscopically suspicious for FIP, a definitive diagnosis of FIP could only be made by histology (including immunhistochemical staining).