Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1111/j.1744-697X.2009.00163.x

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japanese Agricultural Systems Society  

In an effort to appropriately manage and preserve grasslands, the application of species–area curves using the randomized-order method was examined for species diversity measurements. First, surveyed orders were permuted using repeated random number generation and, on average, a typical species–area relationship was generated. A power function model was then fit to the curves and three diversity indices were compared: minimal area ( <i>A</i><i>_a</i>), species richness (<i>S</i><i>_a</i>), and the appearance pattern (<i>z</i>) resulting from the model. We investigated <i>Zoysia</i>–dominated pastures to test simulations using several treatments and to compare methods. The results indicated that the randomized-order method produced highly precise species–area curves and that the effects of survey and stand area on the curves and indices were minimal. This method offers an improvement over species–area relationships generated from surveyed orders and over other species diversity indices, and is thus useful for evaluating species diversity in grasslands.

DOI： 10.14962/jass.25.1_45

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Language：Japanese   Publisher：Japanese Society of Grassland Science  

DOI： 10.14941/grass.54.344

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Other Link： http://agriknowledge.affrc.go.jp/RN/2010771109

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Grassland Science  

In semi-natural grassland, the vegetation changes seasonally and annually. Therefore, to examine problems related to long-term vegetation change, we must understand the influence of study season on the vegetation diagnosis. This study investigated the phenological characteristics of Miscanthus (M)- and Zoysia (Z)-dominated grasslands. We established twenty 100×100cm quadrats in each grassland. In each quadrat, we identified all of the species, determined coverage and maximum height for each species, and vegetation cover and canopy height in spring, summer, and autumn. We calculated species diversity indices and vegetation similarity for each season. In both M- and Z-grasslands, the extended summed dominance ratios (E-SDR_2) of the dominant species changed seasonally. The number of species and vegetation height increased with the season in M-grassland, but not in Z-grassland. The vegetation similarity among seasons was lower in M-grassland. Therefore, the seasonal change in vegetation in M-grassland was greater than in Z-grassland. By contrast, the Shannon index (H') and Simpson index (D) differed little among seasons in each grassland, suggesting that the diversity index can be used to evaluate the grassland condition with long-term vegetation succession.

DOI： 10.14941/grass.55.48

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Other Link： https://agriknowledge.affrc.go.jp/RN/2010772836

Language：English   Publishing type：Research paper (scientific journal)  

To evaluate the carbon (C) sequestration function of grassland soils in Japan, soil C stocks were measured in 24 grasslands (3-43-year-old pastures) across 14 livestock farms nationwide. Soil C stocks varied among soil types, and the values in the upper 25 and 50.cm were higher in Andosols (mean, 12.4 and 19.3 kg m-2, respectively) than in Brown Forest soils (7.5 and 13.7 kg m-2) and other soil types (5.5 and 7.5 kg m-2). At the same time, C stocks varied among pastures within each soil type. Compared to data from the published work on the C content shortly after pasture establishment, aged pastures had decreasing C concentrations as the soil depth increased, suggesting substantial C accumulation in the top soil layers during pasture aging. This C accumulation caused grassland soils to store as much C as adjacent forest soils. Although the C stocks in the grassland soils were not statistically different from those in the adjacent native forest soils, some grassland areas stored greater amounts of C than the forests, indicating a possibility of increasing soil C stocks through improved grassland management. Journal Compilation © 2009 Japanese Society of Grassland Science.

DOI： 10.1111/j.1744-697X.2009.00145.x

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Grassland Science  

This study investigated buried seeds in pastures converted from paddy fields and grazed for various grazing years with cattle : Pastures T1 (grazed at the first year from the conversion), T2 (at the second year), N3 (at the third year) and N8 (at the eighth year), so as to predict the extent of weed damage in rice when the converted pastures were reconverted again to paddy field. Buried seed species were found at 15, 18, 21 and 29 species in pastures T1, T2, N3 and N8, respectively, and paddy field weed species were at 9, 8, 11 and 11 in each of pastures. The number of buried seed of paddy field weeds was the largest in pasture T2 (5,640 seeds/m^2 in the 0 to 10cm layer), followed by pastures T1 (2,534), N3 (2,394) and N8 (2,012). The numbers of buried seed of non-paddy-field weeds and of whole weed communities were larger in pasture N8 than in pastures T1, T2 and N3. In all the pastures, the number of seed of non-paddy-field weeds was larger than those of paddy field weeds and sown herbage. From the results, we concluded that the risk of weed damage would not always decrease as increase of grazing years when pastures converted from paddy fields are reconverted to paddy field again.

DOI： 10.14941/grass.54.57

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Other Link： http://agriknowledge.affrc.go.jp/RN/2010760736

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DOI： 10.1111/j.1744-697X.2007.00095.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC RANGE MANAGEMENT  

Although the precision of herbaceous biomass estimation depends on the sample number, the spatial heterogeneity of the biomass, and sampling procedures, the magnitudes of the influences on the precision have not been clarified. We simulated virtual plant communities based on the gamma distribution to clarify the relationships between the precision of estimating herbaceous biomass and the number of samples, sampling density, spatial heterogeneity of the biomass, and sampling procedures. Using only two parameters, the gamma distribution can approximate the frequency distribution of herbage mass with varying heterogeneity. Our simulations demonstrated that the number of samples is a more influential factor than sampling density on the precision of the herbaceous biomass estimation. Moreover, our simulations confirmed that biomass heterogeneity strongly affected the precision and quantified the magnitude of the influence. When we estimated biomass with random sampling and a 50 X 50 cm quadrat and accepted estimation error of +/- 10% of the mean for a confidence interval of 95%, the numbers of samples needed were 200, 77, and 9 for very, intermediate, and less heterogeneous grasslands, respectively. Similarly, when we estimated biomass with a ranked set sampling (RSS), then 24, 15, and 4 samples were needed in very, intermediate and less heterogeneous grasslands, respectively. We came to two conclusions: 1) In less heterogeneous grasslands, good precision of estimation can be obtained with a small number of samples, and it is useful to employ RSS. The cutting method, as well as nondestructive methods, will be practical; and 2) estimation for heterogeneous grassland requires a large number of samples, and it is not so useful to employ RSS. For that reason, more research is needed on nondestructive methods.

DOI： 10.2111/1551-5028(2007)60[447:NOSRFE]2.0.CO;2

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Grassland Science  

Conversion of paddy fields into pastures for use by grazing cattle is an important option for animal production and conservation of agricultural land in Japan. However, trampling by animals on the high-moisture soil in the converted pastures may lead to degradation of sown forage species and generation of weeds. This study investigated vegetation characteristics and soil moisture content in three paddy-field pastures varying in grazing history, Pastures T (first to second years of grazing), N3 (third year) and N8 (eighth year), and also in a pasture in an upland field as a control (Pasture C, second year). Botanical composition was determined using the dry-weight-rank method. The soil moisture content was highest in Pasture N3, followed by Pastures T, N8 and C. The number of paddy-field weed species occurring in Pastures T, N3, N8 and C was 10, 16, 8 and 1, respectively. The dominance by paddy-field weeds was higher in Pasture N3 than in Pastures T and N8. The proportion of total weeds (paddy-field+non-paddy-field type) in plant biomass was lower in Pasture T than in Pastures N3 and N8. The proportion of paddy-field weeds in the total weeds decreased as the grazing year increased.

DOI： 10.14941/grass.52.219

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Other Link： http://agriknowledge.affrc.go.jp/RN/2010734525

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DOI： 10.1111/j.1744-697X.2006.00048.x

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1111/j.1744-697X.2005.00036.x

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPIE-INT SOC OPTICAL ENGINEERING  

Polarimetric analysis of solar rays reflected from the Earth's surface is expected to play a particularly important role in future Earth environment observation, and an imaging liquid crystal tunable filter (LCTF) spectropolarimeter for the near-infrared wavelength band has been developed by the Japan Aerospace Exploration Agency(JAXA) over the past several years for such analysis. In order to realize the practical application of the optical sensor, efforts are currently under way to develop it into sensor package for airborne observation system. This paper first presents the concept and architecture of an optical observation system using an LCTF spectropolarimeter which is sensitive to radiation in the 650-1100 nm near-infrared wavelength band. The results of farm and grassland observations using a near-infrared LCTF imaging spectropolarimeter are then presented by spectral images of observed crop specimen and grass, and radiances of solar rays reflected from the crop and grass are shown. The results of a measurement of water-purity conducted using models of a ploughed and irrigated rice field are also presented by the spectral radiances of solar rays reflected from such field models. Finally, the applicability of the LCTF spectropolarimeter to agro-environment observation is summarized based on the results of these outdoor experiments.

DOI： 10.1117/12.578148

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Grassland Science  

The relationships between various environmental factors and the appearance of Anthoxanthum odoratum and Carex albata in sown pasture were analyzed by discriminant analysis. Then correlations of coverages with soil pH, soil nitrogen concentration (soil N), and soil available phosphate concentration (soil P) were examined. Discriminant coefficients of soil moisture and slope degree against A. odoratum were positive, but the coefficient of soil hardness was negative. Coverage increased with decreases in soil N and P. On the other hand, in the case of C. albata, the discriminant coefficient of depth of humus layer was positive and the coefficient of soil pH was negative. C. albata coverage significantly increased with the decrease in soil pH. The results indicated that A. odoratum tends to grow well in conditions of low fertility such as on a steep slope but that it is susceptible to drought stress. Thus, enhancement of the competitiveness by fertilization would be an effective means to protect sown grasses against A. odoratum. On the other hand, the results indicated that C. albata prefers conditions of abundant nutrition and has a high level of tolerance to acid stress. Thus, modification of soil acidity, not fertilization, would be an effective mean to protect sown grasses against C. albata.

DOI： 10.14941/grass.49.611

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Other Link： http://agriknowledge.affrc.go.jp/RN/2010690121

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Grassland Science  

DOI： 10.14941/grass.47.509

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Other Link： http://agriknowledge.affrc.go.jp/RN/2010640992

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)   Publisher：岐阜大学農学部  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Grassland Science  

Experiments to determine grassland features using spectral characteristics were performed. Spectral reflectance was measured, using a hand-held spectrometer, at 102-151 random points in five Italian ryegrass(Lolium multifeorum Lam.)meadows under different vegetation conditions. The measurements were used for three applications:1)to visualize the relationship between red and near infrared spectral characteristics, 2)to determine the spatial pattern of aboveground biomass and apply it to gamma distribution, and 3)to determine the spatial pattern of plant coverage. The red-near infrared spectral reflectance relationship that was derived was a brief and clear index for the degree of dense or sparse coverage or the area of bare soil in grassland. Analysis of the biomass and coverage histograms determined different patterns for different plant growth or grassland conditions. Biomass distribution could be determined more accurately, both qualitatively and objectively, by applying the gamma distribution. Thses results suggest that several kinds of grassland features could be determined in a short period of time using spectral data measured with an hand-held spectrometer.

DOI： 10.14941/grass.47.237

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Other Link： http://agriknowledge.affrc.go.jp/RN/2010632179

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Grassland Science  

Pleioblastus chino var.viridis can dominate under severe grazed conditions. To understand the reason for this dominance, we investigated the dry matter composition ratio of each part in the plant body and dry matter production in two plots;grazed and ungrazed. Leaf production and grazed mass during a grazing period were estimated using a regression formula between the standing crop of leaf and the leaf increase rate. The dry matter composition ratio of rhizome in the grazed plot was higher than that in the ungrazed plot. On the other hand, the ratio of stem in the grazed plot was lower than that in the ungrazed plot. The ratio of leaf in the grazed plot was almost equal to that in the ungrazed plot during the grazing period. Annual net production in grazed and ungrazed plots was estimated at 670gDM/m^2 and 647gDM/m^2, respectively. From the obtained results, we consider as follows. The increase in composition ration of rhizome under grazed conditions has the advantage of increasing the security of the bud and the storage of reseve substance for regeneration of leaves after a disturbance. Thus, the increase in the ratio of rhizome with the decrease in stem contributed to active leaf production and high annual net production. The high net production under grazed conditions enabled the dominance of P.chino var.viridis to occur.

DOI： 10.14941/grass.47.262_1

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Other Link： http://agriknowledge.affrc.go.jp/RN/2010632183

Language：English   Publishing type：Research paper (bulletin of university, research institution)  

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：日本動物園水族館協会  

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Grassland Science  

Pleioblastus chino var. viridis can dominate under severe grazing conditions. To understand the reason of this dominance, we investigated the maintenance mechanism of stem density of P. chino var. viridis in three plots; grazed, 1-year-ungrazed and ungrazed ones. The stem weight was ranked, grazed< 1-year-ungrazed<ungrazed plots. On the contrary, the stem density was in the reverse order, because there are differences in both the rhizome bud density and the bud utility ratio among plots. The rhizome bud density was ranked, grazed (8619/m^2)>1-year-ungrazed (6303/m^2)> ungrazed (789/m^2) plots. The bud utility ratio was also ranked, grazed (47%)<1-year-ungrazed (35%)>ungrazed (17%) plots. These traits were considered to be responsible for the enhanced dominance of P. chino var. viridis under severe grazing conditions. In both 1-year-ungrazed and ungrazed plots, the relationship between mean aboveground weight per stem and stem density seemed to follow a thinning line with a gradient of -3/2. This density regulation of P. chino Var. viridis was caused by intraclonal controls of rhizome as well as by both intraclonal and interclonal competitions.

DOI： 10.14941/grass.44.328

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Other Link： http://agriknowledge.affrc.go.jp/RN/2010590155

Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Grassland Science  

For investigating the influence of digestibility on energy efficiencies for grazing heifers, following energy constituents were estimated from some measurements on Italian ryegrass (Ir) pasture and perennial ryegrass (Pr) pasture. Let available herbage energy supply (HA), grazing intensity based on fasting metabolism (GI) and consumed herbage energy by heifers (HCE) be described usign unit of GJ/10a/grazing period ; and energy retention (DRE ; estimated by ARC's method) and heat prodution (DHP ; estimated from heart rate), metabolizable energy intake (DMEI ; DRE + DHP) be described by unit of MJ/F/day, where F is fasting metabolism estimated by ARC's method. Using GI and HA, HCE was expressed as following equation : HCE = 12.6GI - 70.5GI^2/HA - 0.248 (R^2 = 0.81). The values of HCE estimated from this equation were similar to those estimated on tall fescue pasture in the previous report. Pelationships between DMEI and DRE were expressed as follows : on Ir pasture in spring, DRE = 0.63 DMEI - 1.76 ; on Pr pasture in spring, DRE = 0.65 DMEI - 1.72 + on Ir and Pr pasture in summer, DRE = 0.43 DMEI - 1.04. The regression coefficients in above equations, including those on tall fescue pasture in the previous report, were positively correlated to in vitro dry matter digestibility in each pasture significantly.

DOI： 10.14941/grass.38.396

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Other Link： http://agriknowledge.affrc.go.jp/RN/2010481176

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Animal Science  

The heart rate memory apparatus enables a minute-by-minute determination of heart rate in cattle grazed on pastures for up to 24 hours. In the present study, the properties of the apparatus and the accuracy of heart rate determination in a field was investigated using Holstein heifers and adult cows. The A-B lead is suitable for measuring heart rate using this apparatus, because the wave form in the A-B lead is larger and more stable than that in other leads. Heart rates ranging from about 50 beats per minute to 160 could be measured accurately. Daily heart beats (DHB) in the heifers grazed on pastures for 24 hours (which is a day and a night) were about 140, 000, and 0.20 to 0.45% of DHBs were false and excessively counted. These false counted beats occurred mostly during a grazing period. Based on these findings, the heart rate memory apparatus was confirmed to be a suitable tool in measuring heart rates with a high degree of accuracy in cattle grazed on pastures.

DOI： 10.2508/chikusan.63.295

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Other Link： https://jlc.jst.go.jp/DN/JALC/00367133984?from=CiNii

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Animal Science  

DOI： 10.2508/chikusan.63.332

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Language：English   Publisher：Japanese Society of Grassland Science  

For investigating the influence of digestibility on energy efficiencies for grazing heifers, following energy constituents were estimated from some measurements on Italian ryegrass (Ir) pasture and perennial ryegrass (Pr) pasture. Let available herbage energy supply (HA), grazing intensity based on fasting metabolism (GI) and consumed herbage energy by heifers (HCE) be described usign unit of GJ/10a/grazing period ; and energy retention (DRE ; estimated by ARC's method) and heat prodution (DHP ; estimated from heart rate), metabolizable energy intake (DMEI ; DRE + DHP) be described by unit of MJ/F/day, where F is fasting metabolism estimated by ARC's method. Using GI and HA, HCE was expressed as following equation : HCE = 12.6GI - 70.5GI^2/HA - 0.248 (R^2 = 0.81). The values of HCE estimated from this equation were similar to those estimated on tall fescue pasture in the previous report. Pelationships between DMEI and DRE were expressed as follows : on Ir pasture in spring, DRE = 0.63 DMEI - 1.76 ; on Pr pasture in spring, DRE = 0.65 DMEI - 1.72 + on Ir and Pr pasture in summer, DRE = 0.43 DMEI - 1.04. The regression coefficients in above equations, including those on tall fescue pasture in the previous report, were positively correlated to in vitro dry matter digestibility in each pasture significantly.

DOI： 10.14941/grass.38.396

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Other Link： http://agriknowledge.affrc.go.jp/RN/2010481176

DOI： 10.2508/chikusan.63.295

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Language：Japanese   Publisher：Japanese Society of Animal Science  

DOI： 10.2508/chikusan.63.332

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