Carbon Depletion by Plowing and its Restoration by No‐Till Cropping Systems in Oxisols of Subtropical and Tropical Agro‐Ecoregions in Brazil

The continuous use of plowing for grain production has been the principal cause of soil degradation. This project was formulated on the hypothesis that the intensification of cropping systems by increasing biomass‐C input and its biodiversity under no‐till (NT) drives soil restoration of degraded agro‐ecosystem. The present study conducted at subtropical [Ponta Grossa (PG) site] and tropical regions [Lucas do Rio Verde, MT (LRV) site] in Brazil aimed to (i) assess the impact of the continuous plow‐based conventional tillage (CT) on soil organic carbon (SOC) stock vis‐à‐vis native vegetation (NV) as baseline; (ii) compare SOC balance among CT, NT cropping systems, and NV; and (iii) evaluate the redistribution of SOC stock in soil profile in relation to soil resilience. The continuous CT decreased the SOC stock by 0·58 and 0·67 Mg C ha⁻¹ y⁻¹ in the 0‐ to 20‐cm depth at the PG and LRV sites, respectively, and the rate of SOC sequestration was 0·59 for the PG site and ranged from 0·48 to 1·30 Mg C ha⁻¹ y⁻¹ for the LRV site. The fraction of C input by crop residues converted into SOC stock was ~14·2% at the PG site and ~20·5% at the LRV site. The SOC resilience index ranged from 0·29 to 0·79, and it increased with the increase in the C input among the NT systems and the SOC sequestration rates at the LRV site. These data support the hypothesis that NT cropping systems with high C input have a large potential to reverse the process of soil degradation and SOC decline. Copyright © 2013 John Wiley & Sons, Ltd.     

Dimensional analysis in surface irrigation

The surface-irrigation design process requires multiple analyses of surface irrigations to test tentative values of design parameters in the search for an optimum. Preparation of general design charts can aid the design process if the users' test cases fall within the scope of the charts. The large number of independent variables in surface irrigation preclude the generation of charts covering the practical range of all independent variables, when these are in dimensioned form. Dimensionless formulations allow significant reductions in the amount of data generated and presented, without loss of generality. Relationships pertinent to surface-irrigation analyses and design are reviewed in dimensionless terms. Dimensionless forms are developed primarily from an examination of the equations governing surface-irrigation phenomena. Additionally, dimensionless forms are derived from a study of the dimensions of the pertinent variables, without recourse to the governing equations. The Buckingham Pi Theorem is derived in the context of surface irrigation. Different choices for reference variables, leading to different meanings for the resulting dimensionless parameters, have advantages and disadvantages for analysis and design of surface irrigation systems. The different systems developed in the past for border irrigation are reviewed and their consequences noted; new systems with potential for future studies are suggested. Particular attention is devoted to those dimensionless representations useful in design.     

Effect of induced compaction by wheel traffic on soil physical properties and yield of maize in Romania

Results of field experiments with soil compaction induced by wheel traffic applied uniformly to cover the entire surface of the experimental plots are reported. Compaction was done immediately before sowing, and each year, in each location, the same treatments were repeated on the same plots. The number of tractor passes varied between 0 and 30. The experiments were conducted during the 1978–1981 period in four locations with different soil and climatic conditions.Changes in soil physical properties, as well as in the yield of maize grain, were shown to be related to the number of tractor passes according to regression formulae of the type: Y = aX^b. Most of the changes were recorded between 0 and 8–10 passes, while with more than 15–20 passes changes became negligible. The average maximum increase in bulk density was 20–25% as compared with the non-compacted control plot, and the average maximum decrease in yield was 46%. Moisture content in the compacted control plot, and the was 2–3% (w/w) lower than in the control plot, except for the soils with poor drainage where the lower part of the compacted topsoil showed an increase in moisture content. Air content in the compacted plots often dropped below 10, and occasionally to nearly 0% (v/v). For three of the four locations, grain yield of maize linearly decreased by 13 kg ha^?1 (or 0.18% of the control plot yield) for each 1 kg m^?3 increase in bulk density.     

RADIOGRAPHIC CHANGES IN TESTES OF BULLS INFECTED WITH BESNOITIOSIS

Ten beef bulls infected with Besnoitiosis were examined radiographically and pathologically. Eight of these were slaughtered soon after diagnosis; two were left for a six-month observation period. The radiographic findings were focal and branching-tree calcification of the testes. Histopathologic examination proved these calcifications to be necrotic sections of the seminiferous tubules. Radiography of the testes as a means of evaluating the fertility status of the infected bull is recommended.     

Induced Disease Resistance in Plants by Chemicals

Plants can be induced locally and systemically to become more resistant to diseases through various biotic or abiotic stresses. The biological inducers include necrotizing pathogens, non- pathogens or root colonizing bacteria. Through at network of signal pathways they induce resistance spectra and marker proteins that are characteristic for the different plant species and activation systems. The best characterized signal pathway for systemically induced resistance is SAR (systemic acquired resistance) that is activated by localized infections with necrotizing pathogens. It is characterized by protection against a broad range of pathogens, by a set of induced proteins and by its dependence on salicylic acid (SA) Various chemicals have been discovered that seem to act at various points in these defense activating networks and mimic all or parts of the biological activation of resistance. Of these, only few have reached commercialization. The best- studied resistance activator is acibenzolar-5-methyl (BION). At low rates it activates resistance in many crops against a broad spectrum of diseases, including fungi, bacteria and viruses. In monocots, activated resistance by BION typically is very long lasting, while the lasting effect is less pronounced in dicots. BION is translocated systemically in plants and can take the place of SA in the natural SAR signal pathway, inducing the same spectrum of resistance and the same set of molecular markers. Probenazole (ORYZEMATE) is used mainly on rice against rice blast and bacterial leaf blight. Its mode of action is not well understood partly because biological systems of systemically induced resistance are not well defined in rice. Treated plants clearly respond faster and in a resistant manner to infections by the two pathogens. Other compounds like beta-aminobutyric acid as wdl as extracts from plants and microorganisms have also been described as resistance inducers. For most of these, neither the mode of action nor reliable pre-challenge markers are known and still other pathways for resistance activation are suspected. Resistance inducing chemicals that are able to induce broad disease resistance offer an additional option for the farmer to complement genetic disease resistance and the use of fungicides. If integrated properly in plant health management programs, they can prolong the useful life of both the resistance genes and the fungicides presently used.     

Estimation of biomass change in montane forests in Norway along a 1200 km latitudinal gradient using airborne laser scanning: a comparison of direct and indirect prediction of change under a model-based inferential approach

The current study compared two approaches for estimating change of aboveground biomass (AGB) in montane forests in Norway using field- and remotely sensed data from airborne laser scanning (ALS) from two points in time (four-year interval). The first was an indirect method that involved modeling and prediction of AGB at two points in time using ALS metrics as predictors, estimating the change from differences between AGB predictions. The second was a direct method, where change was modeled and predicted directly using differences between corresponding ALS metrics derived at the two measurement occasions as predictors, and the estimate was based on the predicted differences. Both methods were applied over a 1500?km long and 250?m wide transect from south to north in Norway comprising 250?m² grid cells. The results showed that the indirect method was more precise than the direct method. The indirect method estimated 0.65?Mg?ha^?1 change in AGB over the observation period, with a corresponding 95% confidence interval of ±0.27?Mg?ha^?1. The corresponding figures for the direct method was 0.54 and ±0.51?Mg?ha^?1. The direct method has been recommended previously. We conclude that the indirect method is both more precise and versatile.     

Genome-enabled prediction models for black tea (Camellia sinensis) quality and drought tolerance traits

Genomic selection in tea plant (Camellia sinensis) breeding has the potential to accelerate efficiency of choosing parents with desirable traits at the seedling stage. The study evaluated different genome-enabled prediction models for black tea quality and drought tolerance traits in discovery and validation populations. The discovery population comprised of two segregating tea populations (TRFK St. 504 and TRFK St. 524) with 255 F₁ progeny and 56 individual tea cultivars in validation population genotyped using 1,421 DArTseq markers. Twofold cross-validation was used for training the prediction models in the discovery population on eight different phenotypic traits. The best prediction models in the discovery population were consequently fitted to the validation population. Of all the four model-based prediction approaches, putative QTLs (Quantitative Trait Loci) + annotated proteins + KEGG (Kyoto Encyclopaedia of Genes and Genomes) pathway-based prediction approach showed more robustness. The findings have for the first time opened up a new avenue for future application of genomic selection in tea breeding.     

Beitr?ge zur Kenntnis der Baumkrankheiten

Ohne ZusammenfassungDiffertation der Staatsrwirtschastlichen Fakultät der Ludwig-Marmilians-Universität zu München.     

Oxidation von „unverändertem”︁, methyliertem und hydriertem Lignin in Gegenwart von SiO2 and Hydrochinon (1,4-Dihydroxybenzol)

Oxidation of ?unalterated”?, methylated and hydrogenated lignin in the presence of SiO₂ and hydroquinone (1,4-dihydroxybenzene) Under the conditions choosen, which were similar to those in soils, peats and composts, the oxidation by hydroquinone and its (aut-) oxidation products was generelly greater on the methylable than on the hydrogenable structures of lignin. Especially phenolic and enolic hydroxy as well as aldehyde groups, but also single aliphatic double bonds in propene side chains, phenyl cumarone systems, stilbenoide structures as well as such conjugated to aldehyde and ceto groups forced the O₂-absorption on lignin.     

Methoxylgehalt,PSR und Farbreaktionen bei Wurzel- und Strohlignin von Triticum

Methoxyl content, PSR and color reactions on root and straw lignin The wet chemical measured content of methoxyl groups is in lignin from up to 13 cm long roots and straw with ～ 11,5 % nearly indentical. Lignin in roots contains more keto groups. This was proved by psr-spectroscopy (δ = 8 ppm) and by various color reaction with o–dianisidine/HCl, diphenylamine, acridine, barbituric acid, p-anisidinhydrochloride, sulfanilic acid and aniline. Root lignin has also more benzolic protons (δ = 5,35 – 5,45 ppm) and by far higher part of highly shielded aliphatic protons (δ = 1,33 ppm). The last diminished to a large extend after having react with diazomethane. From this informations could even be concluded that lignin in roots has more methylable structures. Against that protons in the side arms are to find more in the lignin of straw.