 Distribution patterns of DOC, UV absorbance at 254 nm, and fluorescence components were investigated in the oligo/meso-haline zone for three distinct wetland-influenced rivers.  Oligo/meso-haline regions of coastal wetland rivers are found to be highly dynamic with regards to the biogeochemical behavior of DOM.  The application of EEM-PARAFAC demonstrated non-conservative behavior in certain groups of DOM and possible change of dissociation state of acidic functional group of DOM, which would not have been possible to detect using more traditional optical properties measurements.*Highlights (for review) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 salinity range (salinity < 10) of the oligo/meso-haline zone for three distinct wetland-influenced 8 rivers; namely the Bekanbeushi River, a cool-temperate river with estuary lake in Hokkaido, 9Japan, the Harney River, a subtropical river with tidally-submerged mangrove fringe in Florida, 10USA, and the Judan River, an acidic, tropical rainforest small river in Borneo, Malaysia. For the 11 first two rivers, a clear decoupling between DOC and A 254 was observed, while these parameters 12showed similar conservative behavior for the third. Three distinct EEM-PARAFAC models 17lake were also found to be transported upstream. In the Harney River, whereas upriver-derived 18terrestrial humic-like components were mostly distributed conservatively, some of these 19 components were also derived from mangrove inputs in the oligo/meso-haline zone.

Recently, the size of livestock farms in Japan has been expanding and the pollution from farm wastes has become a serious problem in rural areas. Therefore it is necessary to design treatment strategies and improve the recycling of livestock manure for sustainability of agriculture in Japan. The dairy cattle waste management systems were studied at dairy farms in Aomori prefecture and in Hokkaido, Japan. The four farms, typical for the respective regions in Japan, were investigated on the basis of the land and livestock size, housing, overall farm and waste management, type of machinery and a farm labour force. A statistical comparison was made for housing, milking and waste handling systems of dairy farms. One of the waste handling strategies was aerobic slurry treatment and land irrigation of the treated liquid fraction. Such methods began to solve some of waste management problems created since 1967 in grassland farming areas of Hokkaido. The irrigation system supplies water fertiliser and organic material to land as well as shortening the spreading times. It recycles livestock resources, increases the soil fertility and rationalizes the farm management.

Chromophoric dissolved organic matter (CDOM) leached from leaf litter is a major source of humus in mineral soil of forest ecosystems. While their functions and refractoriness depend on the physicochemical structure, there is little information on the quality of CDOM, especially for that leached in the very early stages of litter decomposition when a large amount of dissolved organic matter (DOM) is leached. This study aimed to better understand the variations/changes in the composition of CDOM leached from senescent leaf litter from two tree species during the early stage of decomposition. Leaf litter from a conifer tree (Japanese cedar, D. Don) and a deciduous broad-leaved tree (Konara oak, Thunb.) were incubated in columns using simulated rainfall events periodically for a total of 300 d at 20°C. The quality of CDOM was investigated based on the fluorescence properties by using a combination of excitation-emission matrix fluorescence (EEM) and parallel factor analysis (PARAFAC). In addition, the phenolic composition of DOM was investigated at a molecular level by thermally assisted hydrolysis and methylation-gas chromatography-mass spectrometry (THM-GC-MS) in the presence of tetramethylammonium hydroxide (TMAH). The EEM was statistically decomposed into eight fluorescence components (two tannin/peptide-like peaks, one protein-like peak, and five humic-like peaks). A significant contribution of tannin/peptide-like peaks was observed at the beginning of incubation, but these peaks decreased quickly and humic-like peaks increased within 1 mo of incubation. The composition of humic-like peaks was different between tree species and changed over the incubation period. Since tannin-derived phenolic compounds were detected in the DOM collected after 254 d of incubation on THM-GC-MS, it was suggested that tannins partially changed its structure, forming various humic-like peaks during the early decomposition.

Spatial information on the quantity and quality of forage is important for practicing precision agriculture in grasslands. The objective of this research was to generate a field map of the concentrations of total digestible nutrients (TDN) and crude protein (CP) of forage in an orchardgrass-dominated meadow field (0.6 ha) using a hyperspectral imaging sensor. The sensor was mounted on the roof of a vehicle in order to scan the whole meadow field. Calibration models to estimate the concentrations of the chemical components were developed using a dataset consisting of observed concentrations and spectral data acquired from the hyperspectral images. The models were developed by multiple linear regression analysis with stepwise variable selection, and were evaluated by cross-validation and evaluation index (EI) methods. The cross-validation for the calibration model using 10 explanatory variables resulted in R 2 values of 0.74 and 0.76 for TDN and CP, respectively. Standard error of prediction (SEP) was, respectively, 4.51 and 1.04. Bias was close to 0 for both TDN and CP. The EI values ranged 28.1-29.4, showing rank C. These results show that the calibration models are practical for estimating the concentrations of TDN and CP. Finally, field maps of the concentrations of TDN and CP were generated by applying the calibration models to field-scale image data. The maps were able to identify the variations in the concentrations of TDN and CP throughout the field. In conclusion, this system is a useful technique for obtaining maps of forage chemical composition for site-specific field management.Field mapping using hyperspectral imaging Y. Suzuki et al.

This study investigated seasonal and geographical variation in the fluorescence properties of dissolved organic matter (DOM) in a river system that includes rice paddy fields in its watershed. The river system covers a northern area of the main island of Japan, and between 6 and 45% the watershed area of the tributaries is paddy fields. Water samples were collected monthly from eight tributaries for 1 yr, and the fluorescence properties of DOM were monitored by combined excitation-emission matrix (EEM) and parallel factor analysis. The EEM was statistically decomposed into six fluorescence components with different environmental dynamics. The relative proportion of these components varied with season and geographic location, the former having a greater effect than the latter. Seasonal variation is largely attributed to changes in the source of DOM associated with irrigated rice cultivation practice. The fluorescence component composition showed a stronger autochthonous signature, which varied over a wider range during off-cropping period (October-April) than cropping period (May-September). During the cropping period, a large amount of allochthonous DOM with relatively similar quality was transported into river water from flooded paddy fields and masked the variability in the quality of DOM among tributaries. Therefore, irrigated rice cropping practices are considered to be one of major factors that influence seasonal and geographical variation of fluvial DOM composition.