The effects of long-term conservation tillage, crop residues and P fertilizer on soil conditions and responses of summer and winter crops on an Andosol in Japan

A field experiment was conducted from 1983 to 1992 in Tsukuba, Japan to investigate the effects of tillage on soil conditions and crop growth in a light-colored Andosol. Three tillage methods (NT: no-tillage, RT: no-tillage for summer cropping and moldboard plowing for winter cropping, and CT: conventional rotary tillage to a depth of 15 cm) were employed in combination with crop residue application (+R, −R) and fused magnesium phosphate (FMP) fertilization (+P, −P). Under the combination of NT and +R, diurnal variation of soil temperature at a depth of 5 cm was smaller during the summer cropping season and soil temperature in the daytime was lower during the winter cropping season than under CT. Soil inorganic N concentration at a depth of 0–30 cm was +R > −R and NT > RT > CT. The early growth of summer crops was accelerated under NT in comparison with CT, and yields were higher under NT and RT in comparison with CT. On the other hand, winter crop yields were significantly reduced under NT, while they were still higher under RT in comparison with CT. Yields were higher with +R and +P application, respectively, and these effects were more pronounced in winter cropping. The positive effect of FMP fertilization was greater in combination with NT, and that of residue treatment was greater in combination with RT and NT than with CT. In conclusion, the best tillage practice for Andosols on the Kanto Plain is RT, i.e. a combination of NT for summer cropping and CT for winter cropping. The application of NT for winter cropping is not recommended, although the application of phosphate and crop residues could reduce the risk of yield reduction, because of improved soil nutrient status and moderation of diurnal soil temperature.     

Automatic detection of washboarding in bandsaws

This paper presents an on-line method for detecting washboarding generated in bandsaws. It uses a parameter based on the shape of sawing force amplitude distributions. The curve of the probability density function of the parallel sawing force amplitude obeyed a normal distribution for the normal sawn surface, but it changed to an M-shaped distribution when washboarding appeared on the sawn surface of the workpiece. The curve of probability density function of the normal sawing force amplitude obeyed the normal distribution for any sawn surface investigated. The workpiece including a knot did not influence use of the parameter for detecting the appearance of washboarding.     

Selective determination and formation of elemental selenium in soils

A selective method for the determination of elemental selenium in soil was developed and was applied to the study of elemental selenium in soil. (1) Elemental selenium extracted with carbon disulfide from soil was selectively transformed into selenocyanate ion by reacting with potassium cyanide in carbon disulfide. The selenocyanate ion formed was recovered into an aqueous solution and the amount of selenium in the aqueous solution was determined. This method was specific to elemental selenium and did not interfere with the other selenium compounds and soil components. The method was also highly sensitive and enable to determine more than 0.1 μg kg^-1 of elemental selenium in soil. (2) The formation of elemental selenium was confirmed, when a soil was submerged and the redox potential of the soil decreased. The amount of elemental selenium formed was proportional to the selenite content of the soil, indicating that elemental selenium is transformed from selenite upon its reduction.     

Automatic detection of a damaged cutting tool during machining I: method to detect damaged bandsaw teeth during sawing

This paper presents an on-line method for detecting damaged teeth in the bandsaw using acoustic emission (AE) signal energy. The method is based on an analysis of differences in AE energies generated by normal and damaged teeth during sawing. Because of the difference in the amount of sawing, the AE energy was low for sawing by the damaged tooth and high for sawing by the normal tooth immediately after the damaged tooth. The ratio of AE energy for two successive teeth — a normal tooth immediately following a damaged tooth — was much greater than 1, whereas the ratio of AE energy for two successive normal teeth was close to 1. The results demonstrate that the technique using the AE energy ratio for two successive teeth is effective for on-line detection of damaged bandsaw teeth.Part of this paper was presented at the 9th Annual Meeting of the Chugoku Skikoku Branch of the Japan Wood Research Society, Tottori, October 1997     

Performance of coated carbide tools when grooving wood-based materials: effect of work materials and coating materials on the wear resistance of coated carbide tools

This paper presents the performance of coated carbide tools when grooving various density hardboards and wood-chip cement boards. Work materials of low density (about 0.8g/cm³) and high density (about 1.2g/cm³) were tested. The coating materials studied were chromium carbide, titanium carbonitride, and titanium carbide, which were synthesized on P30 carbide substrate using a chemical vapor deposition method; titanium nitride, chromium nitride, and titanium carbonitride were synthesized using the physical vapor deposition method. Cutting tests were performed during grooving at a cutting speed of 1000m/min and a feed rate of 0.1 mm/rev. The results of the study show that the coated carbide tools are more advantageous in reducing the progression of tool wear and retaining lower normal force and noise level when cutting both hardboard and wood-chip cement board of high density than was the uncoated carbide tool. The wear rate of the coated carbide tools for the wood-chip cement board increased more rapidly than that of the hardboard with increasing densities. Though the coated carbide tools suffered more wear with the low-density wood-chip cement board than with hardboard, their normal force and noise level were always lower for the low-density wood-chip cement board.Part of this paper was presented at the 11th Annual Meeting of the Chugoku Shikoku branch of the Japan Wood Research Society, Matsue, Shimane, September 25, 1999     

Control of Verticillium Yellows in Chinese Cabbage by the Dark Septate Endophytic Fungus LtVB3

ABSTRACT Three hundred forty-nine fungal endophytes were obtained from a total of 1,214 root segments of eggplant, melon, barley, and Chinese cabbage grown as bait plants in a mixed soil made up of samples from different forest soils in Alberta and British Columbia, Canada. Three of the 349 isolates, when inoculated in axenically reared Chinese cabbage seedlings grown in petri dishes, almost completely suppressed the effects of a postinoculated and virulent strain of Verticillium longisporum. Two isolates effective against the pathogen were Phialocephala fortinii, which had been obtained from the roots of eggplant and Chinese cabbage. The third isolate was a dark septate endophytic (DSE) fungus obtained from barley roots. Hyphae of P. fortinii grew along the surface of the root and formed microsclerotia on or in the epidermal layer. Hyphae of the DSE fungus heavily colonized root cells of the cortex. Seedlings grown for 1 week in the presence of the endophytes were then challenged with the Verticillium pathogen. In DSE-treated roots, some of cell walls in the epidermal and cortical layers showed cell wall appositions and thickenings, which appeared to limit the ingress of the pathogen into adjacent cells. Such marked host reactions were not observed in the root cells colonized by P. fortinii. Chinese cabbage preinoculated with the above endophytes and, for comparison, a previously reported disease-suppressive fungal endophyte, Heteroconium chaetospira, were transplanted into the field and disease symptoms were assessed. The DSE could most effectively inhibit the development of Verticillium yellows, with reductions in the percentages of external and internal disease symptoms of 84 and 88%, respectively. The protective values against the disease are extremely high compared with those of other isolates. Most of the DSE-treated plants in the plots achieved marketable quality.     

Mycoplasma ovis detected in free-living Japanese serows, Capricornis crispus

Nineteen blood samples collected from free-ranging wild Japanese serows, Capricornis crispus, between 2006 and 2008 in Iwate prefecture were examined for the hemoplasma infection by real-time PCR targeting the 16S rRNA gene. Five (26.3%) out of the 19 samples were positive in real-time PCR with an average melting temperature at 85.18 °C. The positive samples in the real-time PCR were reconfirmed by conventional PCR, and one of them was successful for direct DNA sequencing. The nucleotide sequence of the 16S rRNA gene of the representative stain was identical to that of Mycoplasma ovis. This was the first demonstration of hemotropic mycoplasma infections among the free-living Japanese serows in Japan.     

Performance of coated carbide tools in turning wood-based materials: Effect of cutting speeds and coating materials on the wear characteristics of coated carbide tools in turning wood-chip cement board

This paper reports on the performance of coated carbide tools in turning wood-chip cement board. The coating materials studied were titanium carbonitride (TiCN), titanium nitride (TiN), chromium nitride (CrN), and titanium nitride/aluminum nitride (TiN/AlN), which were synthesized on the P30 carbide substrate. The aim is to investigate the effect of coating materials and cutting speeds on the wear characteristics of the coated carbide tools. Cutting tests were performed when turning wood-chip cement board at cutting speeds of 30, 40, 50 and 60 m/s, a depth of cut of 1mm, and a feed of 0.05 mm/rev. The results of the study show that the coated carbide tools provided better performance than the P30 carbide tool, especially in terms of reducing the progression of the wear rate and clearance wear. The TiN/AlN-coated carbide tool showed the smallest increase in both wear rate and clearance wear with an increase in cutting speed and had the longest tool life among the coated carbide tools investigated. Though the TiCN-coated carbide tool was observed to have a low wear rate and low clearance wear for cutting speeds of 30 and 40m/s, when the cutting speeds were >50m/s its wear rate and clearance wear were almost the same as those of CrN-and TiN-coated carbide tools, which had high values for these parameters.Part of this paper was presented at the 21st IUFRO World Congress, August 2000, Kuala Lumpur, Malaysia     

Nodulation during vegetative growth of soybean stage does not affect the susceptibility to red crown rot caused by Calonectria ilicicola

Soybean cultivar Enrei and its derivative lines, non-nodulating En1282 and supernodulating Sakukei 4, were grown in an experiment field naturally infested with the red crown rot fungus, Calonectria ilicicola, to determine whether nodulation elicits the disease. Infection frequency by the fungus invariably increased with time and reached about 100% 6 weeks after sowing. Disease severity was invariably slight until 8 weeks after sowing. At harvest, however, disease severity was lowest in En1282 and highest in Sakukei 4. Enrei was intermediately susceptible. Sakukei 4 produced many more nodules than Enrei, while En1282 completely failed to nodulate. For three other pairs of nodulating and non-nodulating isogenic lines, all non-nodulating lines had lower severity than their nodulating counterparts at harvest. Pot experiments with Enrei and its derivatives revealed that inoculation with Bradyrhizobium sp. did not affect disease severity during the vegetative stage of plant growth, i.e., 6 weeks after sowing. These results suggested that the production of nodules in the vegetative stage is not, at least directly, related to susceptibility to the disease, but physiologic changes after anthesis vary depending on the nodulation traits in the respective soybean lines, resulting in different levels of susceptibility to red crown rot.