In this study, we performed a greenhouse experiment to investigate the effect of cow manure biochar on maize yield, nutrient uptake and physico‐chemical properties of a dryland sandy soil. Biochar was derived from dry cow manure pyrolysed at 500 °C. Cow manure biochar was mixed with a sandy soil at the rate equivalent to 0, 10, 15 and 20 t biochar per hectare. Maize was used as a test crop. Results of the study indicated that cow manure biochar contains some important plant nutrients which significantly affected the maize crop growth. Maize yield and nutrient uptake were significantly improved with increasing the biochar mixing rate. Application of biochar at 15 and 20 t/ha mixing rates significantly increased maize grain yield by 150 and 98% as compared with the control, respectively. Maize net water use efficiency (WUE) increased by 6, 139 and 91% as compared with the control, with the 10, 15 and 20 t/ha mixing rate, respectively. Nutrient uptake by maize grain was significantly increased with higher biochar applications. Application of cow manure biochar improved the field‐saturated hydraulic conductivity of the sandy soil, as a result net WUE also increased. Results of the soil analysis after the harvesting indicated significant increase in the pH, total C, total N, Oslen‐P, exchangeable cations and cation exchange capacity. The results of this study indicated that application of cow manure biochar to sandy soil is not only beneficial for crop growth but it also significantly improved the physico‐chemical properties of the coarse soil.

Using the Chandra Advanced CCD Imaging Spectrometer Imaging array (ACIS-I), we have carried out a deep hard X-ray observation of the Galactic plane region at (l, b) ≈ (28. • 5, 0. • 0), where no discrete X-ray source had been reported previously. We have detected 274 new point X-ray sources (4 σ confidence) as well as strong Galactic diffuse emission within two partially overlapping ACIS-I fields (∼ 250 arcmin 2 in total). The point source sensitivity was 1 code 662, NASA/GSFC, ∼ 3 × 10 −15 erg s −1 cm −2 in the hard X-ray band (2 -10 keV) and ∼ 2 × 10 −16 erg s −1 cm −2 in the soft band (0.5 -2 keV). Sum of all the detected point source fluxes accounts for only ∼ 10 % of the total X-ray flux in the field of view. Even hypothesizing a new population of much dimmer and numerous Galactic point sources, the total observed X-ray flux cannot be explained. Therefore, we conclude that X-ray emission from the Galactic plane has truly diffuse origin. Removing point sources brighter than ∼ 3 × 10 −15 erg s −1 cm −2 (2-10 keV), we have determined the Galactic diffuse X-ray flux as 6.5 ×10 −11 erg s −1 cm −2 deg −2 (2-10 keV). Only 26 point sources were detected both in the soft and hard bands, indicating that there are two distinct classes of the X-ray sources distinguished by the spectral hardness ratio. Surface number density of the hard sources is only slightly higher than that measured at the high Galactic latitude regions, indicating that majority of the hard sources are background AGNs. Following up the Chandra observation, we have performed a near-infrared (NIR) survey with SOFI at ESO/NTT. Almost all the soft X-ray sources have been identified in NIR and their spectral types are consistent with main-sequence stars, suggesting most of them are nearby X-ray active stars. On the other hand, only 22 % of the hard sources had NIR counterparts, which are presumably Galactic. From X-ray and NIR spectral study, they are most likely to be quiescent cataclysmic variables. Our observation suggests a population of 10 4 cataclysmic variables in the entire Galactic plane fainter than ∼ 2 × 10 33 erg s −1 . We have carried out a precise spectral study of the Galactic diffuse X-ray emission excluding the point sources. Confirming previous results, we have detected prominent emission lines from highly ionized heavy elements in the diffuse emission. In particular, central energy of the iron emission line was determined as 6.52 +0.08 −0.14 keV (90 % confidence), which is significantly lower than what is expected from a plasma in thermal equilibrium. The downward shift of the iron line center energy suggests non-equilibrium ionization states of the plasma, or presence of the non-thermal process to produce 6.4 keV fluorescent lines.

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A survey in Japan showed that approximately 7% of eggplant fruits contain cadmium (Cd) concentrations above the international limit for fruiting vegetables. This study was conducted to develop a method to reduce Cd concentration in eggplant fruits. We determined Cd concentrations in eggplants grown on different rootstocks in Cd-polluted soil, unpolluted soil and nutrient culture. Grafting onto Solanum torvum reduced eggplant fruit Cd concentrations by 63-74% in Cd-polluted soil and unpolluted soil compared with grafting onto Solanum melongena and Solanum integrifolium. Stem and leaf Cd concentrations of scions on S. torvum were approximately 30% of those on S. integrifolium, so Cd translocation from roots to shoots was apparently reduced in plants grafted onto S. torvum. Stem and leaf Cd concentrations of S. torvum were also lower than those of cv. Senryou2 (S. melongena) and cv. Daitarou (S. melongena); thus, Cd translocation from roots to shoots was also reduced in self-rooted S. torvum plants. The Cd concentration of xylem sap in stems of S. torvum was 22% of that in stems of S. melongena, so the reduced Cd translocation from root to shoot could be accounted for by differential loading of Cd into the xylem in roots. We have developed a practical method for reducing the Cd concentration of eggplant fruits by grafting onto S. torvum rootstock. Further investigation is needed to elucidate the mechanism responsible for the low Cd translocation characteristics of S. torvum.

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This paper describes the first light and subsequent test observations with the 8.2 m aperture Subaru Telescope constructed at the summit of Mauna Kea. Following the engineering first light, which started 1998 December, the astronomical first light and test observations were carried out in 1999 January with 4 testing instruments under seeing conditions of 0″.2*#x2013;0″.5 for near-infrared and 0″.3–0″.6 for optical wavelengths. The actively supported primary mirror was shown to achieve an overall imaging performance of 0″.1 (FWHM) or better in the absence of any atmospheric disturbance. The pointing accuracy of the telescope is about 1″ rms, and a closed-loop tracking accuracy of ≲ 0″.07 rms has been achieved. Infrared images of the Orion Nebula covering 5′ × 5′, obtained with J, K″, and H2v = 1–0 S(1) filters, have revealed much finer and fainter details of the BN/KL region, the bright bar, and other conspicuous features compared with previous observations. K′ band photometry of 516 point sources yielded a luminosity function with a peak at K′ ∼ 12 mag with a long tail in K′ ∼ 13 mag down to K″ ∼ 17 mag, suggesting a fairly large number of young brown dwarfs existing in the Trapezium cluster. Several new features around the Orion BN/KL region are also reported.