-
Tiefu Pan
1993 年 48 巻 5 号 p.
747-750
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
In this paper, meteorological data recorded in Changchun from 1909 to 1988 and historical data were examined, in order to analyze the agroclimatic ecology index and forecast the long-range climate with deduction year by year and climatic cycle. The relationships between climatic change and the Heavenly Stems, the Earthly Branches, Solar activities and El Nino are investigated. Based on this the writer released forecasts of temperatures and rainfall for the subsequent crop growth season (from May to September) in Jilin province. The six year forecast was correct for the six year real climate (1985-1990).
抄録全体を表示
-
Xin'an Liu, Bolum Wang, Guirui Yu
1993 年 48 巻 5 号 p.
751-754
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
In this paper, the regression effects, accuracies and figures of three mathematical models for simulating light vertical distribution in rice canopy were compared. The model
Sz=Soea+bLAI (z) was the best. The quantitative relationships between
a, b and LAI (z) accumulated to a height above the ground, solar altitudes were discussed. A universal available model for light distribution in crop canopy was proposed, and the error in utilizing the model was analysed. Meanwhile, daily changes in light intensity in representative layers of the canopy were described by harmonic analysis.
抄録全体を表示
-
Wang Yongqin
1993 年 48 巻 5 号 p.
755-758
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Based on an analysis of natural disasters which occur in some major damage regions in Henan Province, China, including frequency of disasters, their objects and characteristics, this paper emphasizes the fact that many AgMDs are disastrous consequences resulting from Man's own doing. Considerable agricultural yield reduction over a vast extent of fields has always resulted from AgMDs, especially from droughts and floods occurring in areas of Henan Province.
These disasters are characterized using the concepts of synchronizing, overlapping, alternating, succesive occuring etc.. The new point of view of “natural disaster masses (or chains)”, “entropy addition” and the “systems analysis method” should be applied in analysing, understanding and preventing AgMDs.
In the last part of this article, some measures and proposals for preventing and fighting disasters are presented.
抄録全体を表示
-
M. Takaichi
1993 年 48 巻 5 号 p.
759-762
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Effects of micro-scale topography on near dawn temperature distributions in a complex terrain were examined using micro-scale topographic factors, which calculated with 25m or 50m grid height data. A spatial near dawn temperature pattern over a small area could be explained well by a multiple regression equation of topographic factors for 500m or 1000m square areal units. Height data from the 25m grid showed higher correlation than 50m grid. The effective factors for estimating temperature distribution were the sky view factor, catchment area, height differences from the lowest point and the degree of directional exposure. Distributions of nighttime temperature drops were also examined and could be explained by the same factors. An example of an estimate for minimum air temperature distribution using these factors and data at meteorological observing stations are shown. The percentage of frost damaged buds on tea bushes were also expressed by the topographic factors. Attention should be paid not to extrapolate far from the range of samples because of the statistical basis.
抄録全体を表示
-
An Shunqing, Zhu Zixi, Wu Naiyuan, Jiao Yizhen
1993 年 48 巻 5 号 p.
763-766
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Experimental data relatd to various types of soil water treatment for winter wheat an summer maize carried out in Gongxian, Henan Province and Taian, Shandong Province were used to expound on the relationship between crops, soil and atmosphere and on the behavior of water consumption by means of a defined optimal water consumption and water stress indices, An optimal irrigation scheme for winter wheat from the viewpoint of improving water use efficiency and economic benefit was proposed. It is found that this scheme is successful and of great significance for the problem of alleviating water resource deficiencies in this region.
抄録全体を表示
-
Pan Tiefu
1993 年 48 巻 5 号 p.
767-770
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
The climate in Northeast China has been growing warmer and the rainfall in central and northern parts of Northeast China has decreased. Agricultural production in Northeast China has changed greatly. Thus, appropriate measures should be taken.
抄録全体を表示
-
Keiko Kai, Mikiko Kainuma, Naomi Murakoshi, Kenji Omasa
1993 年 48 巻 5 号 p.
771-774
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Strong correlations were found between blooming dates and meteorological factors. Based on these correlations, predictive maps of blooming dates in the Japanese Islands were proposed for each case of 1, 2 and 3°C of warming. The correlation was tested for the blooming dates of
Prunus yedoensis, Prunus mume, Camellia japonica, Taraxacum, Rhododendron kaempferi, Wistaria floribunda, Lespedeza bicolor, Hydrangea macrophylla, Lagerstroemia indica, Miscanthus sinensis, etc., using the data of monthly mean temperatures, warming indices and cold indices from 102 meteorological stations in Japan between 1953-1990. Simple and multiple regression analyses were used for the correlation.
Among meteorological factors, the strongest correlation was shown for monthly mean temperatures. Notably, the strongest was obtained for the case of
Prunus yedoensis. The cold index and mean temperature of the previous December also showed the best correlation for species such as
Prunus mume and
Camellia japonica. Strong correlations between the leaf color-changing dates of Ginkgo biloba and Acer palmatum and the monthly mean temperature were found in one month of autumn. In these species, there was a delay of 2-7 days with a 1 degree increase in mean temperature.
The 30-year 1km
2 temperature-climate mesh-file developed by the Japan Meteorological Agency was used for the phenological estimation and predictive maps of blooming dates. Each observatory station was classified according to its annual mean temperature. Blooming for each mesh was estimated through monthly mean temperatures and regression equations of corresponding stations. Then, distribution maps of predictive blooming dates distinguished by 5-day divisions were made.
抄録全体を表示
-
J. F. Angus, M. Stapper, J. R. Donnelly
1993 年 48 巻 5 号 p.
775-778
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Australian crops and pastures are grown in climates which are relatively variable at present and may become more variable if the. global climate changes. Optimal management in relation to this variability has two strands. The best-bet management
strategy must be identified for the long-term climate and modified with any climate change. Variation in weather between years, however, is already greater than changes in the mean expected from climate change, so improved management
tactics to cope with current variability will lead to systems with long-term resilience.
Examples using the SIMTAG and maNage models are described for improved strategic and tactical management of rainfed wheat. SIMTAG is used to clarify the extent to which regional yields are currently limited by weather and to make a strategic assessment of optimal sowing date. The maNage model is used for tactical management of supplementary N fertiliser for dryland wheat. maNage shows that the reliability of yield response is increased if the N is applied at the terminal spikelet stage but only if the amount of stored soil water is above a defined threshold.
Future integration of crop models with pasture models is discussed. Pastures make up the largest landuse on farms in the region. They have special importance because they influence the growth of crops grown in sequence. Modelling the interaction of pastures-crop sequences and crop-crop sequences in relation to weather is important for increasing yields of both crops and pastures.
抄録全体を表示
-
FELINO P. LANSIGAN
1993 年 48 巻 5 号 p.
779-782
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Risk and uncertainty in rice production due to weather a evaluated under the present and anticipated climatic change conditions. Expect rice yields and yield variabilities as well as yield exceedance probability curves a estimated for selected locations using an ecophysiological crop growth model. Simulation results indicate higher expected yields, lower yield variability, and lower probability of crop failure during the wet season than in the dry season. Evaluation of rice crop growth under a probable climatic change show negligible to significant effects on crop yields and optimal growing periods across several locations.
抄録全体を表示
-
S. R. Holman, D. Bachelet
1993 年 48 巻 5 号 p.
783-786
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
The Chinese rice cultivar Ai-Nan-Tsao was grown to maturity in- two replicate experiments under three CO
2 treatments or three temperature treatments in growth chambers for the purpose of exploring the root growth dynamics of rice under possible future climatic changes. The CO
2 treatments were ambient, 550ppm, or 700ppm CO
2 held constant during the experiment and the temperature treatments were 27°/22°C, 30°/25°C, or 34°/28°C day/night temperatures with a photoperiod of 13 hours for all treatments. Root and shoot growth was significantly enhanced by both elevated CO
2 treatments, with the greatest increases occurring during vegetative growth. There was no difference between elevated CO
2 treatments. Roots responded much more to CO
2 than did shoots (root biomass increased by -130% and shoot biomass by -60% over the ambient treatment). Root/shoot ratios were generally larger under elevated CO
2 during the vegetative phase, but not following panicle initiation. Both elevated CO
2 treatments advanced plant development by approximately 7 days as compared to the ambient treatment. Leaf area, tiller number and leaf dry weight was greater in the high temperature treatment, and leaf area and leaf dry weight was depressed by low temperature at grain maturity. Root and shoot biomass was not significantly affected by the temperature treatments. Yield was reduced by 95% at high temperature, due to a lengthened vegetative growth phase and a delayed onset of flowering. Neither the CO
2 nor temperature treatments altered the rooting pattern with depth in the soil. Because rice root biomass is closely coupled to methane emissions from rice paddies, information about root responses will prove useful in modeling potential future changes in methane emissions under climate change. In addition, such rice root response data is needed to parameterize models being adapted to simulate rice growth under elevated CO
2 concentrations.
抄録全体を表示
-
D. Olszyk, C. Wise, W. M. Werakoon
1993 年 48 巻 5 号 p.
787-790
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
To obtain information for more detailed studies of how rice responds to climate change plants of three high tillering (IR30, IR52, IR74) and two low tillering cultivars (Azuceña and IRAT 104) were grown under controlled environment conditions for 28 days. To detect CO
2 responses, plants were grown at 400μL L
-1 (ambient) or 700μL L
-1 CO
2, at 31/26°C and a 13hr photoperiod. To detect temperature responses, plants were grown at 28/22, 31/25, or 34/28°C light/dark temperatures, ambient CO
2, and a 13hr photoperiod. Across all rice cultivars, a 300μL L
-1 increase in CO
2 stimulated root growth more than shoot growth (p<0.05), i. e. a 12 to 54% increase in root weight, 4 to 49% increase in total dry weight, and 10 to 32% increase in root/shoot ratio; but neither leaf nor stem weight and leaf or tiller number was affected by CO
2. In contrast, increasing temperature by 6°C for 28/22°C stimulated shoot but inhibited root growth, resulting in an increase (p<0.05) (38 to 69%) in leaf number but a significant decrease (32 to 48%) in root/shoot ratio and nonsignificant changes for other parameters. Cultivars responded similarly to CO
2 or temperature; there were no significant CO
2 x cultivar or temperature x cultivar interactions. However, rice cultivars responded differently to the same environment; IRAT 104 plants tended to have lower dry weights and tiller numbers than the IR cultivars with Azuceña as intermediate. Azucena had lower root/shoot ratios than the other cultivars.
The information in this document has been funded wholly or in part by the U. S. Environmental Protection Agency. It has been subjected to me Agency's peer and administrative review, and it has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
抄録全体を表示
-
S. MOHANDASS, T. M. THIYAGARAJAN, S. PALANISAMY, A. ABDUL KAREEM
1993 年 48 巻 5 号 p.
791-794
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Using an eco-physiological model, the changes in the growth characteristics and grain yield for elevated atmospheric CO
2 level and temperature are explored. The main prediction is for harvest indices to fall. The model was used to develop strategies for mitigating the combined effects of increased temperature and CO
2, and define rice ideotypes suited to changing climate.
抄録全体を表示
-
M. J. Kropff, K. G. Cassman, F. W. T. Penning de Vries, H. H. van Laar
1993 年 48 巻 5 号 p.
795-798
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
To cope with estimated population growth in Asia, attainable rice yield potential must increase in the irrigated lowlands. At odds with this goal is the fact that yield potential of released high yielding rice varieties has remained constant since the release of IR8 in the late 1960s, although yield per day increased as a result of shorter growth duration and host plant resistance was improved. For example, highest rice yields of IR72 (released in 1987) were 6 and 9.5tha
-1, in the 1991 wet season and the 1992 dry season, respectively, in a tropical environment with good agronomic management. These yields are comparable but no higher, than the highest yields attained by IR8 in the same environment more than 20 years ago. Detailed growth analysis from these recent studies allowed us to improve an eco-physiological model for rice growth. Subsequent simulations demonstrated accurate prediction of wet and dry season rice yield. The model was then used to evaluate the effects of global climate change as expected by the year 2020. Changes in temperature and atmospheric CO
2 had relatively small effects on simulated rice growth and yield compared with (1) the impact of crop management practices in high-yielding environments and (2) genetic improvement that could further increase yield potential. Varieties with a longer grain filling duration will be needed to increase the yield plateau and to reverse negative effects of increased temperature.
抄録全体を表示
-
H. Nakagawa, T. Horie, J. Nakano, H. Y. Kim, K. Wada, M. Kobayashi
1993 年 48 巻 5 号 p.
799-802
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
The effects of elevated CO
2 concentrations and high temperatures on growth and development were investigated in the Japonica rice cultivar ‘Akihikari’ which was grown in two temperature gradient tunnels (TGT) newly developed by the authors. The TGT system provided temperature gradients along the long axis of the tunnel of up to 4°C above the ambient in Kyoto, Japan, while maintaining natural daily and seasonal temperature variations. The daytime CO
2 concentration in one tunnel was kept at an ambient level (≈350ppm), and that in the other at 840ppm in 1990 and 690ppm in 1991 during the entire growing season. Three N fertilization levels (0.3, 1.2, 2.4g/pot) were created at each temperature × CO
2 treatment in TGT.
The elevated CO
2 slightly promoted leaf area development at the initial stage, though this effect decreased with growth, resulting in only a small effect at the heading stage. The nearly doubled CO
2 concentrations increased the crop dry weight at the intermediate N level by 24% at the heading and 16% upon maturity on average over different temperature conditions. The enhancement rates of the doubled CO
2 in the panicle dry weight under outdoor temperature conditions were 15, 30 and 24% at the low, intermediate and the high N applications, respectively. Panicle dry weights under ambient and doubled CO
2 both decreased drastically with temperature rises. These results obtained by long-term experiments under field-like conditions suggested that, although elevated CO
2 concentrations in the atmosphere promote crop dry matter production, the effects on yield are significantly influenced by temperature and N conditions.
抄録全体を表示
-
Zhiqing Jin, Xilian Zheng, Juan Fang, Daokuo Ge, Hua Chen
1993 年 48 巻 5 号 p.
803-806
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
The potential impact of climate changes on winter wheat production in China was evaluated using an approach liking the CERES-Wheat model to both the local current weather data and the doubled CO
2 climate change scenario generated by the GISS GCM. Changes in overall output of winter wheat in China were also estimated, using a statistical model. Several agroclimatic indices were finally adopted to analyze possible changes in moisture condition, northern limits, varietal disposition, and cropping systems for winter wheat throughout the country.
抄録全体を表示
-
R. Leuning, Y. P. Wang, D. de Pury, O. T. Denmead, F. X. Dunin, A. G. ...
1993 年 48 巻 5 号 p.
807-810
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
A mechanistic simulation model was used to examine the expected responses of wheat to a doubling in atmospheric CO
2 concentration in combination with a 2°C rise in temperature. The model produced satisfactory simulations of total biomass, leaf area and canopy transpiration under present climatic conditions. However, soil evaporation was underestimated by up to 35% by the simulations. Model predictions suggested that increased CO
2 levels should lead to increased biomass and potential yields of wheat up to about 550ppm, after which photosynthesis under full sunlight increases only gradually with CO
2. Higher temperatures are expected to decrease biomass production by shortening the growing season and by increasing plant respiration. A doubling of CO
2 concentration and a temperature increase of 2°C is expected to cause only marginal changes in biomass production. Transpiration use efficiency may be enhanced by -20% with a doubling of CO
2 above current levels.
抄録全体を表示
-
P. K. Aggarwal, S. K. Sinha
1993 年 48 巻 5 号 p.
811-814
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Effect of increase in carbon dioxide and temperature on growth, development, water use and grain yield of wheat was simulated for several locations of India using a dynamic crop growth simulation model, WTGROWS. Long term average weather data and average soil properties for various agro-ecological zones were input in the model. The effect of climate change on productivity was dependent upon the magnitude of temperature change. At 425ppm CO
2 and no rise in temperature, grain yield at all levels of production increased significantly. In northern India, a 1°C rise in mean temperature had no significant effect on potential yields but irrigated and rainfed yields increased in most places. An increase of 2°C in temperature reduced potential grain yields at most places. The effect on irrigated and rainfed productivity varied with location. The natural climatic variability also had considerable effect on the magnitude of response to climate change. Evapotranspiration was reduced in irrigated as well as rainfed environments. The responses to climate change were closely related to the effects of increased temperature on crop duration.
抄録全体を表示
-
Ryoji Sameshima
1993 年 48 巻 5 号 p.
815-818
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
A growth model for soybean, focusing particularly on its development and leaf expansion, was developed to predict how changes in temperature level (shift of the normal temperature by degrees C) affect soybean growth.
Simulations were conducted with the model with seven temperature levels. Vegetative growth periods were shorter with higher temperature levels. However the length of the seed growth period did not differ among the temperature levels.
Maximum leaf area (total leaf area of each simulated plant at the end of vegetative growth period) changed depending on temperature levels. The balance between developmental rate and leaf area expanding rate, both of which depend on temperature, determined the maximum leaf areas.
At the lowest highest temperature levels, the maximum leaf areas and the length of seed growth periods were almost the same. However, the final dry weight of seeds in highest temperature level was much greater because high temperature hastened development, and thus seed growth was initiated in mid-summer under intense radiation.
抄録全体を表示
-
U. Singh, J. T. Ritchie
1993 年 48 巻 5 号 p.
819-822
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Rice grain yields are highly variable because of year to year climatic fluctuations. Long-term climatic data from two sites in the Philippines were used to quantify yield variability as predicted by the CERES-Rice model. Temperature scenarios depicting 0-5.5°C increases were superimposed on the long-term historical data. With increased temperature the model predicted a sharp decline in yield. However, much of the yield decline was offset by the use of a high temperature-tolerant variety. The rice grain yields were markedly higher and the water-use efficiency improved at a CO
2 concentration of 540ppm. Positive effects of climatic change were most pronounced with the improved rice variety and the high nitrogen management.
抄録全体を表示
-
Masatoshi AOKI, Takashi MACHIMURA, Yoshiaki HIDESHIMA, Norio OBASE
1993 年 48 巻 5 号 p.
823-826
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
An empirical model for estimating the daytime (07-16h) mean Bowen ratio, of which independent variables were air temperature (T), relative humidity (RH) and soil moisture tension at 15cm depth (PF), was made using measured data from a sugar beet field. The estimate error of the model was determined by the data measured in another sugar beet field. The standard estimate error of daytime evapotranspiration (E) was also investigated. Calculation from the model showed that an increase in T of 5°C, a decrease in RH of 9% and a decrease in PF of 0.3 induce an increase in E of about 5%, when the Bowen ratio is about 0.3. It is also indicated that the influence of climatic change on evapotranspiration is larger in regions where the soil moisture content is higher.
抄録全体を表示
-
MASAYUKI YOKOZAWA, TOSHIHIKO HARA
1993 年 48 巻 5 号 p.
827-830
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
A dynamic model for growth and mortality of individual plants in a stand is developed, based on the process of canopy photosynthesis, and assuming an allometric relationship between plant height and weight, i.e. an allocation-growth pattern of plant height and stem diameter. The following were shown by simulation: (i) competition between individuals in a crowded stand is never completely one-sided but always asymmetrically two-sided, even though competition is only for light; (ii) plants of the ‘height-growth’ type exhibit a greater asymmetry in competition than plants of the ‘diameter-growth’ type; (iii) the competition mode between plants of the ‘height-growth’ type becomes more asymmetric with increasing photosynthetic ability than with plants of the ‘diameter-growth’ type. These results can explain recent empirical results obtained from several natural plant communities.
抄録全体を表示
-
Changhan Qi, Xinyou Yin, Huaai Xie
1993 年 48 巻 5 号 p.
831-834
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
In the present study, computer language DYNAMO was applied to build a dynamic model of rice growth processes on the basis of synthesizing past quantitative studies on photosynthesis, respiration, assimilate distribution, leaf area growth and organogenesis. The model is referred to as RIce growth CAlendar Model (RICAM). The dynamics of rice crop growth during the field growth period was simulated, and sensitivity to both radiation and temperature was analyzed.
抄録全体を表示
-
T. Kawakata, M. Yajima
1993 年 48 巻 5 号 p.
835-837
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
The heading dates of photoperiod-sensitive rice plants under natural daylength were investigated in this present study. Six cultivars of rice were sown at two-week intervals over one year period in a greenhouse and maintained under constant temperature. Rice plants sown between August and February were consistent in the number of days required from emergence to heading, while those sown between March and July required more time.
Our model is based on accumulated water temperatures from emergence to heading under short daylength conditions, and can be transformed into the developmental index (DVI). The developmental index is the sum of the developmental rates (DVR) from the emergence day, and is 1 on the heading day. The developmental rate was calculated using non-parametric methods.
抄録全体を表示
-
A Test Case in Northern Finland using Satellite Remote Sensing
Yoshio Awaya, Tuomas Häme, Nobuhiko Tanaka
1993 年 48 巻 5 号 p.
839-842
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
It has been predicted that some boreal tree species would migrate north several hundred meters per year to coincide with the predicted global warming due to doubling CO
2 by the middle of next century. It has been said that large parts of the boreal forest and tundra will migrate and disappear because of global warming. Twenty years have passed since the Landsat 1 launching and the average global temperature has shown a tendency to increase over these two decades. The basic concepts of monitoring vegetation shifts using satellite data are described in this paper. A system for the detection of vegetation shifts was tested in northern Finland using Landsat data, however, no clear evidence of shifts was observed.
抄録全体を表示
-
Bian Fujiu
1993 年 48 巻 5 号 p.
843-846
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
By means of landscape ecology, this paper is an attempt to classify the climate, vegetation and land in the Xishuangbanna region as a whole. Based on their relationships, analysis shows how the virgin vegetation decreases while ecosystem entropy increases. Consequently, an assessment of the eco-environment and resources in the region is given.
抄録全体を表示
-
Hidenori TAKAHASHI, Tetsuaki NAGASAWA, Guolian CHEN, Xingmin MU
1993 年 48 巻 5 号 p.
847-850
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
A series of the micrometeorological observations have been carried out on the slopes have of the hilly region of the southeastern part of the Loess Plateau over a two year period from ray 1989. Heat balance on the surface of the slopes which face north and south are roughly estimated from the data of solar radiation, air and soil temperatures and air humidity etc.
The results of these observations show that the direction and gradient of the slopes remarkably affect thermal environments, temperature and soil freeze of the ground in winter. The numerical models of heat flow through the ground, vegetation and boundary layers were applied to estimate the thermal conditions on the slopes. The results calculated from the numerical models are substantially in accord with the observed ones.
抄録全体を表示
-
Keiichi Nakayama, Hisashi Kon, Nobuhiro Matsuoka
1993 年 48 巻 5 号 p.
851-854
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Air temperature, sunshine duration and precipitation are used to estimate the soil moisture in the shallow root zone. The model for the estimation of the soil moisture is based on the water balance of the root zone. The daily amount of evapotranspiration was estimated using the Priestley and Taylor model, modified by the ratio of total soil moisture and soil moisture at the field capacity in a given soil layer. The upward capillary flow was evaluated from the unsaturated hydraulic conductivity of soil and the gradient of water potential between the center of the root zone and at a depth 100cm from the center. This model was used to estimate the soil moisture in the 40cm deep root zone from surface in the Abashiri district in Hokkaido, Japan.
Estimated soil moisture was in agreement with the measured soil moisture by tensiometer in the range of PF 1.8 to PF 2.8. The amount of upward capillary flow was higher than the expected values. Therefore, we concluded that the soil moisture could not be estimated precisely without the estimation of the upward capillary flow.
抄録全体を表示
-
S. Arai, H. Seino
1993 年 48 巻 5 号 p.
855-858
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
In order to elucidate the principles determining plant residue decomposition and humus accumulation in soil, we attempted to make a simple model of soil organic matter accumulation. In this model, soil organic matter accumulation was related to the decomposition rate and annual plant production, both of which were treated as functions of annual temperature. Results of calculations showed tendencies in soil organic matter distribution along a temperature gradient, though the effects of soil factors were considered to be highly significant.
抄録全体を表示
-
H. Seino, Z. Uchijima
1993 年 48 巻 5 号 p.
859-862
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
The productivity of terrestrial vegetation is a determinate element of the carrying capacity of the Earth for all living things including human beings. In this study, the Chikugo model for evaluating the net primary productivity (NPP) from weather data was used to elucidate the global distribution and latitudinal variation of NPP. Predicted NPP varied from below 1t dry-matter ha
-1yr
-1 in high latitude zones and dry regions to 29t dry-matter ha
-1 yr
-1 in tropical wet regions, depending on climatic conditions. The land area with an NPP above 10t dry-matter ha
-1 yr
-1 was only 36.6% of the entire land area. The latitudinal changes in NPP were characterized by a curve with a clear peak in the equatorial zone and two weak troughs in the subtropical high-pressure belts on both hemispheres. The potential global net production by terrestrial plants was estimated to be 136x10
9t dry-matter yr
-1, agreeing well with reports by other researchers. Climate change due to CO
2 doubling would increase NPP by 15-20%.
抄録全体を表示
-
Shunji OHTA, Zenbei UCHIJIMA, Yasuyuki OSHIMA
1993 年 48 巻 5 号 p.
863-866
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Three climatic scenarios of doubled CO
2 (GISS, GFDL, and UKMO) were used to simulate changes in the net primary productivity (NPP) of the natural vegetation of monsoon East Asia due to CO
2-doubling. These three scenarios and baseline climate data were treated to provide gridded data consisting of data nets of 1°×1° meshes. The gridded data thus obtained were utilized together with the Chikugo model to assess NPP with baseline and CO
2-doubling climates. The potential total net production (TNP
0) of East Asia was climatically evaluated as 154×10
8t dry matter yr
-1. The climatic changes induced by doubled CO
2 concentrations could lead to an increase in TNP
0 by 9% to 15%, depending on the climatic scenarios used. The estimated increase in TNP
0 would be limited by the gap between the shift speed of climatic zones and the migration speed of vegetation formations.
抄録全体を表示
-
Atsushi Tsunekawa, Hitoshi Ikeguchi, Mikiko Kainuma, Kazuo Tobe, Kenji ...
1993 年 48 巻 5 号 p.
867-870
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Potential shifts of natural vegetation in Japan caused by global warming were estimated by the steady-state correlation approach. Two types of vegetation distribution model, the fuzzy model and the multinominal logic model, were applied to explain the relationship between the vegetation classification of remaining natural vegetation and climatic conditions. The logic model resulted in a more successful result than the fuzzy model. Thus, the effects of an increase in mean annual temperature were estimated using the logic model. It was indicated that the percentage of grid-cells in all Japan which showed different estimated vegetation classifications from the present classifications were approximately 23% for a 1 degree increase, 44% for a 2 degree increase, and 62% for a 3 degree increase.
抄録全体を表示
-
Haruhiko Yamamoto, Hitoshi Honjo
1993 年 48 巻 5 号 p.
871-874
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
A non-attach and non-destructive measuring method for estimating the leaf area index (LAI) and the biomass (top dry weight, g/m
2) of crops was applied to rice canopies using a portable spectroradiometer under natural conditions in the western part of Japan.
The most effective index of spectral reflection characteristics for estimating the LAI of rice canopies at the vegetative stage is the difference between the values at R
950nm and those at R
550nm. The regression equation is: LAI=0.119 (R
950nm-R
550nm)-0.745. Here, R
750nm and R
550nm are the spectral reflectivities (%) at 950nm and 550nm respectively. The correlation coefficient is 0.974. The most effective index for estimating the biomass of rice canopies at the vegetative stage is the difference between the values at R
1050nm and those at R
550nm. The regression equation is: biomass=13.76 (R
1050nm-R
550nm)-123.5. The correlation coefficient is 0.959.
The observed values and the estimated values were distributed on the ratio line of one to one. The correlation coefficient for the LAI and the biomass were 0.989 and 0.980 respectively, of which the standard errors of prediction were 0.340 and 54.2. These results suggested that the LAI and the biomass could be estimated quantitatively by a non-attach and non-destructive measuring method using a portable spectroradiometer.
抄録全体を表示
-
Hiroshi Tani, Ikuo Horiguchi
1993 年 48 巻 5 号 p.
875-879
発行日: 1993年
公開日: 2010/03/16
ジャーナル
フリー
Two methods of estimating surface albedos using visible and near-infrared data from the AVHRR onboard NOAA-11 are examined. Planetary albedos are derived by narrow-to-broadband conversion with an empirical relationship, and surface albedos are then obtained by correction for the atmospheric attenuation effect (Method 1). In Method 2, spectral albedos are calculated first by atmospheric correction applied for visible and near-infrared data separately, and the surface albedo is obtained by a weighting average as a narrow-to-broadband conversion.
A comparison of the results of Methods 1 and 2 indicates that the latter may yield good estimates. The biases (measured-minus-satellite) of Methods 1 and 2 are -0.067 and -0.022, respectively, and the root-mean-square differences are 0.055 and 0.038. In order to improve the estimation accuracy, it is necessary to apply a bidirectional reflectance model to the estimated isotropic albedos.
抄録全体を表示
