Transfer of carbon incubation parameters to model the SOC and SON dynamics of a field trial with energy crops applying digestates as organic fertilizers

The fertilization with organic amendments and digestates from biogas plants is increasingly used to increase carbon stock and to improve the soil quality, but little is still known about their long-term effects. A common method to analyse organic amendments and their mineralization is incubation experiments, where amendments get incubated with soil while CO₂ release is measured over time. In a previous study, carbon models have been applied to model the carbon dynamics of incubation experiments. The derived parameters describing the carbon turnover of the CCB model (CANDY Carbon Balance) are used to simulate the SOC and SON dynamics of a long-term field trial. The trial was conducted in Berge (Germany) where organic amendments like slurry, farmyard manure or digestates were systematically applied. To grant a higher model flexibility, the amounts of crop residues were calculated for roots and stubble separately. Furthermore, the mineralization dynamics of roots and stubble are considered by the model parameters for each crop. The model performance is compared when using the dry matter and carbon content received from the field trial and the incubation experiments, to evaluate the transferability. The results show that the incubation parameters are transferable to the field site, with rRMSE < 10% for the modelled SOC and rRMSE between 10% and 15% for the SON dynamics. This approach can help to analyse long-term effects of unexplored and unusual organic fertilizers under field conditions, whereat the model is used to upscale the C dynamics from incubation experiments, considering environmental conditions.     

Simulating the soil phosphorus dynamics of four long-term field experiments with a novel phosphorus model

Phosphorus is a nonrenewable resource, which is required for crop growth and to maintain high yields. The soil P cycle is very complex, and new model approaches can lead to a better understanding of those processes and further guide to research gaps. The objective of this study was to present a P-submodel, which has been integrated in the existing Carbon Candy Balance (CCB) model that already comprises a C and N module. The P-module is linked to the C mineralization and the associated C-pools via the C/P ratio of fresh organic material. Besides the organic P cycling, the module implies a plant-available P-pool (P_av), which is in a dynamic equilibrium with the nonavailable P-pool (P_na) that comprises the strongly sorbed and occluded P fraction. The model performance was tested and evaluated on four long-term field experiments with mineral P fertilization, farmyard manure as organic fertilizer and control plots without fertilization. The C dynamics and the P_av dynamics were modelled with overall good results. The relative RMSE for the C was below 10% for all treatments, while the relative RMSE for P_av was below 15% for most treatments. To accommodate for the rather small variety of available P-models, the presented CNP-model is designed for agricultural field sites with a relatively low data input, namely air temperature, precipitation, soil properties, yields and management practices. The CNP-model offers a low entry threshold model approach to predict the C-N and now the P dynamics of agricultural soils.     

Long-term productivity growth and sustainability of Greek irrigated agriculture

The present study examines the long-term productivity growth and sustainability of Greek irrigated agriculture. A log linear trend model was used to measure long-term productivity growth, and the total factor productivity (TFP) approach measures the sustainability of the irrigated production system. A time series database of inputs and outputs data were used for the production period of 1961?–?2001 (41 years) which revealed that there is an increasing trend in the irrigated area of the country. The annual growth rate of the irrigated area is 2.6% during this time period. The long-term trends in yields of crops grown in irrigated agriculture are positive. Fertilizer use rate per ha sharply increases during this period. The productivity of irrigated Greek agriculture also increases over the time period as a result of the introduction of High Yielding Variety (HYV), seed, fertilizer and water technology. The measurement of TFP indices indicates that the long-term trend in productivity growth of irrigated Greek agricultural system is positive. The result implies that the irrigated Greek agricultural production system has long-term sustainability. The result also indicates that fertilizer, fixed capital, rainfall and temperature are positively contributing to the mean production of Greek irrigated agriculture. On the other hand, pesticide, labour and fixed capital reduces variability of irrigated agriculture. To this end, long-term agricultural sustainability depends on patterns of input use.     

Genetically engineering plants for crop improvement

Dramatic progress has been made in the development of gene transfer systems for higher plants. The ability to introduce foreign genes into plant cells and tissues and to regenerate viable, fertile plants has allowed for explosive expansion of our understanding of plant biology and has provided an unparalleled opportunity to modify and improve crop plants. Genetic engineering of plants offers significant potential for seed, agrichemical, food processing, specialty chemical, and pharmaceutical industries to develop new products and manufacturing processes. The extent to which genetically engineered plants will have an impact on key industries will be determined both by continued technical progress and by issues such as regulatory approval, proprietary protection, and public perception.     

Molecular tools--advances, opportunities and prospects

Modern molecular technologies are having a substantial impact in many fundamental and applied areas of parasitology. In particular, polymerase chain reaction (PCR)-coupled approaches have found broad applicability because their sensitivity permits the enzymatic amplification of gene fragments from minute quantities of nucleic acids from tiny amounts of parasite material. Also, high-resolution electrophoretic and genomic methods are finding increased utility. This paper briefly discusses some developments and applications of DNA methods to parasites and highlights their usefulness or potential for those of veterinary importance. Selected examples of applications with implications in fundamental (systematics, population genetics, epidemiology and ecology) and applied (diagnosis, prevention and control) areas are presented. The focus is mainly on tools for the accurate identification of parasitic nematodes and protozoa of socio-economic importance, the diagnosis of infections and the detection of genetic variability using PCR-coupled mutation scanning technology.     

Third‐compartment cannulation in alpacas using a polyurethane gastrostomy tube

Objective To develop a simple and effective surgical technique for third‐compartment cannulation in alpacas. Design Prospective study using six adult male alpacas. Methods General anaesthesia was induced and a polyurethane gastrostomy tube was surgically implanted into the distal portion of the third compartment. Results Three of the alpacas retained their cannulas for a 100‐day period; however, three cannulas were dislodged during the study. Two of the three dislodged cannulas were replaced during a second surgical procedure. Cannulas were well tolerated by the alpacas and all animals remained clinically healthy during the study period. Third compartment contents did not leak from the cannulation site. The tubes were manually removed following the completion of the study and the small defect in the body wall quickly healed over in all animals. Conclusion Surgical placement of polyurethane tubes designed for percutaneous endoscopic gastrostomy is a useful method of cannulating the third compartment in camelids. This technique can be used for experimental studies and possibly could be used for nutritional support and fluid therapy in sick camelids that might need long‐term care.     

Extradural spinal,bone marrow,and renal nephroblastoma

A 1-year-old, female intact Shetland sheepdog presented with acute onset of neurological signs. Physical examination revealed a large abdominal mass. Neurological examination revealed multifocal disease with neck pain, short-strided forelimbs, and hind-limb paresis with loss of tail and anal tone. Blood work, imaging techniques, cytopathology, and histopathology led to a diagnosis of renal, bone-marrow, and extradural spinal nephroblastoma. This report documents potential clinical and pathological manifestations of canine nephroblastoma that have not been previously reported.