Observed and modelled soil carbon and nitrogen changes after planting a Pinus radiata stand onto former pasture

After reforesting pasture land, it is often observed that soil carbon stocks decrease. The present work reports findings from a site near Canberra, Australia, where a pine forest (Pinus radiata) was planted onto a former unimproved pasture site. We report a number of detailed observations seeking to understand the basis of the decline in soil C stocks. This is supported by simulations using the whole-ecosystem carbon and nitrogen cycling model CenW 3.1. The model indicated that over the first 18 years after forest establishment, the site lost about 5.5 t C ha^?1 and 588 kgN ha^?1 from the soil. The C:N ratio of soil organic matter did not change in a systematic manner over the observational period. Carbon and nitrogen stocks contained in the biomass of the 18-year old pine stand exceeded that of the pasture by 88 t C ha^?1 and 393 kgN ha^?1. An additional 6.1 t C ha^?1 and 110 kgN ha^?1 accumulated in above-ground litter. These changes, together with the vertical distribution of carbon and nitrogen in the soil, agreed well with the observation at the site. It was assumed that over 18 years, there was also a loss of 86 kgN ha^?1 from the ecosystem because of normal gaseous losses during nitrogen turn-over and a small amount of nitrogen leaching. Those losses could not be replenished in the pine system without symbiotic biological nitrogen fixation, and there were no fertiliser additions. A simple mass balance approach indicated that the amount of nitrogen accumulating in plant biomass and the litter layer plus the assumed nitrogen loss from the site matched the amount of nitrogen lost from the soil organic nitrogen pool. This reduction in soil nitrogen, together with an unchanged C:N ratio, provided a simple and internally consistent explanation for the observed reduction of soil carbon after reforestation. It supports the general notion that trends in soil carbon upon land-use change can often be controlled by the possible fates of available soil nitrogen.     

Fine-grained recognition of plants from images

Background

Fine-grained recognition of plants from images is a challenging computer vision task, due to the diverse appearance and complex structure of plants, high intra-class variability and small inter-class differences. We review the state-of-the-art and discuss plant recognition tasks, from identification of plants from specific plant organs to general plant recognition “in the wild”.

Results

We propose texture analysis and deep learning methods for different plant recognition tasks. The methods are evaluated and compared them to the state-of-the-art. Texture analysis is only applied to images with unambiguous segmentation (bark and leaf recognition), whereas CNNs are only applied when sufficiently large datasets are available. The results provide an insight in the complexity of different plant recognition tasks. The proposed methods outperform the state-of-the-art in leaf and bark classification and achieve very competitive results in plant recognition “in the wild”.

Conclusions

The results suggest that recognition of segmented leaves is practically a solved problem, when high volumes of training data are available. The generality and higher capacity of state-of-the-art CNNs makes them suitable for plant recognition “in the wild” where the views on plant organs or plants vary significantly and the difficulty is increased by occlusions and background clutter.

     

Nutrient digestibility and prediction of metabolizable energy in total mixed rations for ruminants.

The aim of the present study was to determine equations that predict ME in total mixed rations (TMR) based on routine methods. The ME content of 30 TMR for dairy cows was determined based on digestible crude nutrients obtained with wether sheep. Concentrations in the TMR (in g/kg DM) varied between 118 and 234 for crude protein, 26 and 48 for crude lipid, 131 and 250 for crude fibre, 281 and 488 for NDF, and 173 and 304 for ADF. Gas production ranged from 40.7 to 54.1 ml/200 mg DM, and enzymatically degraded organic matter from 652 to 800 g/kg DM. Digestibility [%] ranged from 68.6 to 84.0 for organic matter, from 55.6 to 84.3 for crude lipid, from 55.0 to 77.8 for crude fibre, from 57.6 to 77.0 for NDF and from 53.1 to 79.6 for ADF. ME ranged from 9.6 to 11.9 MJ/kg DM, and NEL from 5.7 to 7.4 MJ/kg DM. ME content was highly correlated with the concentration of both crude fibre and enzymatically degradable organic matter as well as with organic matter digestibility. A multiple regression equation based on crude fibre and crude lipid predicted ME with a reasonable goodness of fit (r2 = 0.81; s(y.x) = 2.4%). The inclusion of other nutrients, of neutral and acid detergent fibre, neither of gas production did improve the goodness of fit. The best prediction was achieved with inclusion of enzymatically degraded organic matter (r2 = 0.90; s(y.x) = 1.7%).     

The validation of an enzyme immunoassay for the detection of antibodies to bovine leukosis virus

Validation of an enzyme immuno-assay for detection of antibodies against bovine leucosis virus is described in this paper. Internal standardisation of the test was done by means of a negative control serum. With absolute extinction of the negative control serum between 100 and 200 mE, a serum sample is rated positive, if its extinction is 1.5 times above the control. The methodological sensitivity of the enzyme immuno-assay described has proved to be four times as high as that of the immunodiffusion test. The results recorded at five diagnostic laboratories suggested a sensitivity of the test of 97.6 percent (92.1 to 100 percent) and a specificity of 98.1 percent (94.4 to 100 percent). The high efficiency of the test can be confirmed by immunoblotting.     

Bidirectional selection for dustbathing activity in Japanese quail (Coturnix coturnix japonica)

1. Divergent selection was conducted in male Japanese quail for high and low dustbathing activity as measured by the number of dust tosses during a dustbathing bout.

2. After 9 generations of selection the low, control and high lines averaged 6–9, 12.9 and 23.8 dust tosses per dustbathing bout respectively. Realised heritabilities in the low and high lines were 0.21±0.06 and 0.25±0.06 respectively, and agreed well with the heritability coefficient of 0.27±0.04 based on the combined sire and dam estimate from the sib analysis.

3. Correlated responses, similar to those in the selected trait, were found in the duration of the dustbathing bout and in the intensity index (the number of dust tosses per minute during a dustbathing bout). Heritabilities of latency, duration and intensity index were estimated as 0.14±0.04, 0.30±0.04 and 0.26±0.04 respectively.

4. It is concluded that postulated ethological needs may vary considerably between strains according to their genetic background and the previous history of selection of the birds during domestication.     

Morphology of the lymph nodes in bottlenose dolphin (Tursiops truncatus) and striped dolphin (Stenella coeruleoalba) from the Adriatic Sea

Morphology of the lymph nodes was examined in six bottlenose dolphins (Tursiops truncatus) and three striped dolphins (Stenella coeruleoalba) from the Adriatic Sea. All animals had been found dead in nature. One group of the nodes was taken from the tracheal branching area and was marked as bifurcational lymph node, and the other group was taken from the mesenteric root and was marked as mesenteric lymph node. Microscopic analysis showed that the lymph nodes in both dolphin species were surrounded by a connective tissue capsule comprising smooth muscle cells. The parenchyma of the mesenteric and bifurcational lymph nodes in bottlenose dolphin was divided into the peripherally situated cortex with the lymphatic nodules and diffuse lymphatic tissue, and the centrally situated medulla structured of the medullary cords separated by the medullary sinuses. These lymph nodes structurally correspond to the lymph nodes in the majority of terrestrial mammals. The mesenteric lymph node of striped dolphin also had a peripherally situated cortex and a centrally positioned medulla as the majority of terrestrial mammals. In the bifurcational lymph nodes of striped dolphin, there was a central dense lymphatic tissue with the lymphatic nodules and a peripheral less dense lymphatic tissue structured of the cell cords and sinuses. The bifurcational lymph node in striped dolphin resembled porcine lymph nodes and belonged to the inverse lymph nodes.     

Comparison of methods for antimicrobial susceptibility testing and MIC values for pleuromutilin drugs for Brachyspira hyodysenteriae isolated in Germany

In Germany treatment of swine dysentery is hampered by Brachyspira hyodysenteriae strains showing elevated MIC values to the few antibiotics licensed. Therefore, susceptibility testing of clinical isolates is an important service to the swine practitioner. This study compares the established agar dilution procedure for antimicrobial susceptibility testing of this fastidious anaerobe to the broth microdilution test newly developed [Anim. Health Res. 2 (2001) 59; Vet. Microbiol. 84 (2002) 123; J. Clin. Microbiol. 41 (2003) 2596]. A total of 221 isolates were examined twice with either test procedure using tiamulin and valnemulin as antibiotics. Both methods gave reproducible results, and the MIC values for the reference strains B. hyodysenteriae B204 and Staphylococcus aureus ATCC 29213 corresponded to previously published data. However, the results for individual strains differed significantly for both tests (P < 0.001) with MIC values being on average one dilution step lower in the broth dilution method. The 221 strains used for comparing test procedures were isolated between 1989 and 2001. An additional 102 strains isolated in 2002 were tested only with the broth dilution procedure. A significant rise in the average MIC value for both pleuromutilins could be demonstrated when comparing earlier isolates to those from 2000 to 2001 (P < 0.05), while in 2002 the average MIC significantly decreased when compared to the value in 2000 (P < 0.05). However, strains with MIC values for tiamulin as high as 8 microg/ml (broth dilution) could still be isolated.