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Heino Tooming
1993 Volume 48 Issue 5 Pages
501-507
Published: 1993
Released on J-STAGE: March 16, 2010
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The approach of model yields is described, where meteorological data are transformed into categories of abstract yields by means of models. The main model yield categories are the potential yield and the meteorologically possible yield. The meteorologically possible yield is treated as a integrated characteristic of agroclimatic resources.
The following main topics are discussed in this review paper: 1) method of model yields, 2) probabilistic nature of agroclimatic resources and their prediction, 3) territorial distribution of potential resources, 4) have there been changes in potential productivity during our century?
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Masatoshi Yoshino
1993 Volume 48 Issue 5 Pages
509-516
Published: 1993
Released on J-STAGE: March 16, 2010
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First, general trends of agricultural production and changes of air temperature, precipitation and sunshine hours in Japan over the last 100 years are described. In agricultural production or yield, three periods can generally be recognized: period 1, from the end of the 19 century to about 1920, Period 2, from about 1921 to 1945-47, the end or just a few years after the 2nd world war, and Period 3, after the end of the 2nd world war. Secondly, fluctuation of climatic conditions and its effects on the paddy rice yield over the last 104 years were studied statistically in order to evaluate the different impacts according to the periods. By applying the principal component analysis method, their distributions, periodicities and relations to monthly mean air temperature, monthly total precipitation, and monthly total sunshine hours were studied. The first component has a significant correlation to the all three climatic elements in July, and to air temperature and sunshine hours in August and precipitation and sunshine hour in September, In the second part of this study, we classify the 104 years into three periods according to interannual changes of paddy rice yield. For these three periods, the general trends and fluctuations are described and the relationship between the yield and climatic elements are analyzed for five region, respectively.
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Ai Liang Jiang
1993 Volume 48 Issue 5 Pages
517-522
Published: 1993
Released on J-STAGE: March 16, 2010
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The extension of double cropping of rice in the Northern Subtropics of China since the 50's and 60's has yielded significant promotion of grain production at most localities for many years. However, this change in the cropping system also brought about some troubles: the early rice suffered more frequent spring cold and the late rice suffered more frequent autumn cold, etc. The influence of the Tibetan Plateau is considered to be essential to the occurrence of cold air outbreaks in East and Southeast China in spring and autumn as well as in winter. When the jet stream displaces southward from its normal position, it is divided into two branches by the Tibetan Plateau. There appears a trough in the southern branch located in the Bay of Bengal. There is another trough generated due to the dynamic effects of the Tibetan Plateau in the northern branch of jet, and this trough is located east of the eastern boundary of the Plateau. These two troughs are out of phase, and they induce warm and wet air advection in the upper air layer and cold air advection in the lower air layer. Hence long spells of cold and rainy weather appear in the Middle and Lower Reaches of the Yangtze River both in spring and autumn and will do harm to early and late rice.
Comparative studies of spring and autumn cold, between eastern and western parts of the Northern Subtropics of China and their influences on the yields of early and late rice are made.
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Taichi MAKI
1993 Volume 48 Issue 5 Pages
523-530
Published: 1993
Released on J-STAGE: March 16, 2010
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Arid and semi-arid lands account for one third of all land on earth. Desertification is now prevailing and is occasionally linked to the decrease of rainfall due to climatic change, however, it is mainly linked to the adverse human impact i. e., over-cultivation, grazing, deforestation and consumption of water resources.
The United Nations Conference on Desertification (UNCOD) was held at Nairobi, Kenya in 1977, and the Plan of Action to Combat Desertification (PACD) was adopted. Countermeasures against desertification have been carried out in many countries since the conference. However, the effects have not yet met expectations. It is a fact that desertification is still growing significantly.
There are various prevention methods against desertification. They are divided into two countermeasures, i. e., one is social countermeasures with political, economical and educational procedures and the other is technical countermeasures using physical, chemical, biological and ecological techniques. The author presents the research situation regarding the latter cases, prevention methods using (a) windbreaks, (b) covering or mulching by vegetation, films and chemicals (e) irrigation and so on. A concrete prevention technique is introduced as a case study of environmental control or meteorological improvement in China, particularly at Turfan.
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Kai Fu Xiang
1993 Volume 48 Issue 5 Pages
531-535
Published: 1993
Released on J-STAGE: March 16, 2010
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Since the shelterbelt Systems of 1, 092, 260 ha has been established for thirteen years from 1978 having formed 526, 541 networks protected 13, 619, 400 ha, land in western part of Northeast region of China. According to the research work we did in the last five years. The results of research project showed that the shelterbelts has improved the environment significantly. A parameter of comprehensive effects of temperature, moisture and wind in the networks (E
c=246.52-12, 17E+0.58T+6.58U) which is an active method to estimate the affects on shelterbelt on farmland, it's around 21.1-30.9mm/mouth improving the moisture state in dry season helping the crop yield increasing on the average by 19.8%. The effective accumulated temperature (≥10°C) increase by 71°C, the cropland area where suffered wind and frost damage decrease by 80-90%, the grass coverage on the pastureland and grass production increase by 13% and by 49.4-72%, rough protein, rough fat and nitrogen-free extract of grass increase by 3.34%, 2, 4% and 8.4% separately. A large number of fixing sand plantation has been established for over thirty years on shifting sand land in Kerqin sand land, most sand dunes were stable, a great results got from 2, 000ha, experimental area in this region, the atmospheric transport dust decrease by 2, 253t/y, adsorbed dust 11.1t/y and people's eyes sick decrease by 75%. The sandy ecological system develops a relative stable plantation system, the grass, shrubs increase to 200 species from 20 species, insects increase to 400 from 30 species, birds 60 species and other animals increase to 20 from a few species, the fungi increase to over 200 species.
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Yoshihiro Takano, Yuji Hirosawa, Sneo Mori
1993 Volume 48 Issue 5 Pages
537-541
Published: 1993
Released on J-STAGE: March 16, 2010
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This is a report on basic data collection for preparing an environmental management plan to recover the environment in the Aral Sea Basin in Central Asia. This preparatory work covers 1) land resources assessment and 2) a natural resources assessment through analysis of the satellite data and a field survey. Through this preparatory work it is observed that there are several environmental protectional activities being carried out in the Aral Sea region. One remarkable program among them is the construction of a dike between the Small Aral and the Large Aral aiming at the prevention of the environmental degradation of the Small Aral and its surrounding delta areas. Now we believe that an environmental management plan should be worked out urgently on the basis of the full understanding on the present situation of the Aral Sea region.
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O. T. Denmead
1993 Volume 48 Issue 5 Pages
543-550
Published: 1993
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The paper reviews methods for measuring the exchanges of gases between soil-plant systems and the atmosphere, with emphasis on the greenhouse gases CO
2 CH
4 and N
2O The methods vary in scale from chambers covering<1m
2 to convective boundary layer budgets for regions of 100 to 1000 km
2 They should be seen as complementary rather than alternatives, each having a special role.
New micrometeorological approaches are filling gaps in our measurement capabilities: less demanding mass balance techniques, new laser-based gas analysers, and convective boundary layer budget methods which permit estimates of trace gas fluxes on regional scales from relatively simple measurements
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T. Maitani
1993 Volume 48 Issue 5 Pages
551-558
Published: 1993
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A review of several CO
2 flux measuring techniques for plant communities is briefly presented. The development of fast response CO
2 sensors, an international comparison of them, and some results obtained using them are described in this paper. After alternate investigations of the different measuring techniques, 1t was found that they should be used to supply representative information of CO
2 fluxes under various environmental and physiological conditions.
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Bruce A. Kimball
1993 Volume 48 Issue 5 Pages
559-566
Published: 1993
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Under non-limiting water and nutrient supply, prior reviews suggest crops grow about 30% more on the average with a doubling of CO
2 concentration. Reports indicate that water-limiting conditions increase the stimulation of growth by elevated CO
2 more often than they decrease it, but a regression analysis did not reveal significant differences. In contrast, other reports suggest nutrient-limited conditions reduce stimulation of growth by CO
2 enrichment more often than they increase it. Regression analysis of these literature data suggests that on average the CO
2 growth and yield stimulation under nutrient stress were only 74% and 49%, respectively, of the stimulation with adequate nutrients. However, many of the studies were pot or nutrient solution studies which may not represent field conditions. The interaction between CO
2 and temperature appears to be strong and positive, although deleterious effects on harvest index may occur for some species, and increased temperature can shorten he life cycle of determinant crops.
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Takeshi Horie
1993 Volume 48 Issue 5 Pages
567-574
Published: 1993
Released on J-STAGE: March 16, 2010
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For making a rice growth simulation model (SIMRIW; Horie, 1987) applicable to impact predictions of elevated atmospheric CO
2 concentrations and anticipated global warming on yields, the process to determine the direct effect of CO
2 on the growth and one related to high temperature-induced spikelet sterility were incorporated into SIMRIW. The direct effect of CO
2 was incorporated into the model by giving radiation conversion efficiency to crop biomass as a function of CO
2. On the basis of our CO
2 X temperature experiments with rice in temperature gradient tunnels (TGT) and also on information from the literature, the radiation conversion efficiency was estimated to increase by 24% under doubled CO
2 concentrations. The data on high temperature-induced spikelet sterility obtained in TGT were found to fit a logistic type function with respect to averaged daily maximum temperature over the flowering period.
Although the model gave a climatically potential yield, it could be converted into an actual farmers' yield by multiplying by a technological factor. Rice yield estimated by the model with the technological factor explained well the yearly yield variations in Hokkaido (northern Japan) and in Miyazaki (southern Japan). The model, thus synthesized, was applied to assessment of combined effects of CO
2 and global warming predicted by the GISS model (Hansen et al., 1984) under doubled CO
2 in the atmosphere. It was predicted that in northern Japan, doubled CO
2 and the global warming will increase the average yield of irrigated rice by about 20% and will stabilize the yearly variability, and that, in southern Japan, the global environment change will increase the average yield by about 10% though it will also increase instability in the yearly variability by about 2 times that of present due to the increased possibility of high temperature-induced spikelet sterility.
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A Summary of Five Growing Seasons
J. T. Baker, L. H. Allen Jr.
1993 Volume 48 Issue 5 Pages
575-582
Published: 1993
Released on J-STAGE: March 16, 2010
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Projected future climate change includes a strong likelihood of increased atmospheric carbon dioxide concentration ([CO2]) and possible increases in air temperatures. Since 1987, several [CO2] and temperature experiments have been conducted on rice (Oryza sativa, L., cv. IR-30) in outdoor, naturally-sunlit, environmentally controlled, plant growth chambers by USDA-ARS and the University of Florida, at Gainesville, Florida, USA. The objectives of this paper are to summarize some of the major findings of these experiments. Among these experiments, [CO2] ranged from 160 to 900μmol CO2 mol
-1 air while temperature treatments ranged from 25/18/21 to 40/33/37°C (daytime dry bulb air temperature/nighttime dry bulb air temperature/paddy water temperature). Total growth duration was shortened by 10 to 12 days across a [CO2] range from 160 to 500μmol mol
-1 due to a shortened vegetative phase of development and a reduction in the number of mainstem leaves formed prior to panicle initiation. Photosynthesis, growth, and final grain yield increased with [CO2] from 160 to 500μmol mol
-1 but were very similar from 500 to 900μmol mol
-1. Carbon dioxide enrichment from 330 to 660μmol mol
-1 increased grain yield mainly by increasing the number of panicles plant
-1 while increasing temperature treatment above 28/21/25°C resulted in decreased grain yield due largely to a decline in the number of filled grain panicle
-1. Evapotranspiration decreased and water-use efficiency increased with increasing [CO2] treatment while the reverse trends were found with increasing temperature treatment. These results indicate that future increases in [CO2] are likely to benefit rice production by increasing photosynthesis, growth, and grain yield while reducing water requirements. In warmer areas of the world, possible future increases in air temperature may result in yield decreases and increased water requirements.
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Tsuyoshi Akiyama
1993 Volume 48 Issue 5 Pages
583-590
Published: 1993
Released on J-STAGE: March 16, 2010
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The Normalized Difference Vegetation Index based on NOAA data can reveal the progression of desertification, deforestation, and drought damage to arable crops as well as chronological changes in cropping patterns on a regional scale.
Landsat/MSS and /TM data which are characterized by high spectral/ground resolutions have contributed to practical agricultural management. Techniques for crop discrimination and crop mapping have made such rapid progress that we can classify crop types with more than 80% of accuracy. Vegetation Indices derived from Landsat/TM are useful for estimating canopy parameters such as biomass, coverage and leaf area.
Plant stress information including water and nutrient deficits, disease attacks and weed infestation has also been acquired from space. Some attempts to estimate the meteorological damage to crops caused by cold wind and flooding have been successful. Therefore it is considered that satellite remote sensing could be a useful tool for the evaluation of green vegetation.
To promote the evaluation of green vegetation precisely, timely and effectively, it is necessary to: 1) develop sensor systems suitable for vegetation science, 2) develop techniques to combine remote sensing data with other sources of information and models, 3) develop a global vegetation monitoring system.
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P. H. Schuepp
1993 Volume 48 Issue 5 Pages
591-598
Published: 1993
Released on J-STAGE: March 16, 2010
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Our understanding of plant-atmosphere interactions, during this century, focused first on leaf exchange processes of momentum, energy and mass. Non-dimensional expressions of transfer generally reflected adaptations of engineering models for flat plates. Predictions of transfer from many leaves integrated into a canopy ‘continuum’ is complicated by feedback mechanisms between the leaves and their environment. Some common approaches (physiological models, continuum approach through conservation equations, Lagrangian models), and their relative advantages and shortcomings are discussed. Finally, a brief outlook on current observation techniques and their integration with boundary layer studies is presented.
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Kazuto Okamoto
1993 Volume 48 Issue 5 Pages
599-602
Published: 1993
Released on J-STAGE: March 16, 2010
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Tropospheric temperature rises due to the greenhouse effect could be beneficial at high latitudes where the present climate is cold. However the greenhouse effect reduces stratospheric temperature, which could affect the stratospheric ozone depletion. There are two types of ozone depletion. In the first one originally proposed by Molina and Rowland all participating substances are in the gas phase (homogeneous chemistry), but in the second one corresponding to the ozone hole participating substances are in the gas and solid or liquid phases (heterogeneous chemistry). Stratospheric cooling suppresses the first one but enhances the second. The latest calculation shows that the latter effect is larger than the former and the greenhouse effect worsens stratospheric ozone depletion. The combined influence of the greenhouse effect and stratospheric ozone depletion on rice production in Northern Japan, which is known to be climate-sensitive, is investigated. At present, the benefits of the greenhouse effect are much greater than the detriments of ozone depletion, though in the future the detriments might prevail, because the heterogeneous processes are also initiated by strato-spheric sulphate aerosols, which have recently been increasing at an alarming rate. Therefore the argument that the greenhouse effect could be beneficial at high latitudes should be viewed with caution.
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Yukio Omoto, Yasuyuki Aono, Ken Hamotani
1993 Volume 48 Issue 5 Pages
603-606
Published: 1993
Released on J-STAGE: March 16, 2010
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A preliminary study was carried out in order to examine whether evaluations of effects of global warming on the cold requirment of certain types of trees could be of some use in predicting migration of vegetation belts or shifts of cultivation limits of fruit trees. The so called chilling requirment (CR) was chosen as an index for this purpose and the shifts of warmside boundaries of several kinds of trees are examined. Comparisions between CR and other thermal indexes such as the warmth index (WI) and the coldness index (CI) are made. In the study area, i. e., eastern and northern Japan, the correlation between CR and WI is very high so that the regions in which there are trees of a type under consideration are possible with both indexes or not possible with both indexes. It is shown that a uniform warming scenario may destroy the present CR-WI relationship. It is pointed out that flowering data suggests that the warmside boundary of
Prunus yedoensis could be determined by CR. Finally, a general discussion on problems associated with use of the thermal indexes predicting the impact of warming on the distribution of vegetation or trees is given.
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A responce to El Nina event
Yuanzhen XIANG, Chenglan BAO
1993 Volume 48 Issue 5 Pages
607-610
Published: 1993
Released on J-STAGE: March 16, 2010
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An extremely severe flooding took place in early summer of 1991 in the Yangtze--Huaihe Rivers with a loss of US $1.4 billions. In this region in past 40 years, all 3 extremely severe floodings and all 5 severe floodings were observed in same year or next year of El Nino event. The propagation route of impact of El Nino on atmospheric circulation and flooding is also discussed in this paperr
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L. Buendia, A. Valdeavilla, C. Escaño
1993 Volume 48 Issue 5 Pages
611-614
Published: 1993
Released on J-STAGE: March 16, 2010
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The study was conducted in three major rice producing areas to assess the probable impact of climate change in Philippine rice production. Climate change scenarios were devised using general circulation models (GCMs) from ratios of climate variables (temperature, precipitation, and solar radiation) in the doubled CO
2 runs to the current climate variables applied to observed weather data for each site.
The GCMs used were the Goddard Institute for Space Studies (GISS), the Geophysical Fluid Dynamics Laboratory (GFDL), and the United Kingdom Meteorological Office (UKMO). The CERES-Rice IRSNAT Crop Model was modified to simulate the changes in photosynthesis and evapotranspiration caused by increases in atmospheric CO
2. Sensitivity study was performed using step increases in temperature of + 2°C and +4°C combined with step changes in precipitation of +20% and -20%.
Using the mean yield from three sites, results show that under scenario of climate change alone (330ppm of CO
2), an average reduction in rice baseline yield of 22% will be experienced in the Philippines. However, under climate change with physiological CO
2 effects (555ppm of CO
2), an increase in baseline yield (at 330ppm level of CO
2) of only 1% will a obtained. Increasing only the temperature by 2°C without any change in precipitation at 330ppm CO
2 level will correspond to 21% reduction in yield. Further increase in temperature of 4°C will reduce the baseline yield by 39%. Changes in precipitation of -20% and +20% did not significantly affect the rice yields. Considering, however, the physiological effects of CO
2 for sensitivity analysis, rice yields increased by 35% (+0°C), 42% (+2°C), and 58% (+4°C).
Overall, results indicate a wide variation of regional responses to climate change. The Southern part seemed to be more vulnerable to climate change than the Northern Philippines.
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Zhenyao Lin, Xiaolin Chen
1993 Volume 48 Issue 5 Pages
615-618
Published: 1993
Released on J-STAGE: March 16, 2010
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Researching climate variability and anomaly have become an important task for international researchers. The primary emphasis of this paper is to outline the Tibetan climate change and its impact on crop yields. Climate has great influence on agricultural productions in Tibet. The Tibetan plateau is unique both in climatical and agricultural respects. The results are highlighted by three main points:
1. From the 19th century, the most severe calamity is heavy snowstorm in Tibet, especially in the northern parts of Tibet.
2. The climate in Tibet has the trend of becoming dry and warm.
3. In a long period, the variation of crop yields corresponds with the long-period fluctuation of temperature. The change of crop yields in a short term corresponds to precipitation, particularly the one in May and June.
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K. F. A. Lo, S. H. Chiang
1993 Volume 48 Issue 5 Pages
619-622
Published: 1993
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Over the past 90 years, a mean annual temperature increase of about 0.8°C has been observed in a few big cities in Taiwan. Temperature increases would lead to thermal expansion of the oceans and the melting of the Antarctic and Arctic ice sheets. Sea levels would rise, inundating low-lying land areas that include many rice fields, fish and shrimp ponds.
The main objective of this study is to examine the human factors bringing about such temperature changes in Taiwan. The factors considered are the deterioration of air quality, vehicle count, road density, and forest area. To determine what factor has the strongest influence on temperature, correlation analyses were performed between these human factors and the temperature records obtained from 16 Central Weather Bureau observation stations.
The comparisons indicate better relation when correlating pollutant concentrations such as CO, SO
2, and NO
x and temperature. These findings suggest that air quality exerted greater influence on temperature rise did other human factors.
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Huu Ninh Nguyen, Minh Hien Hoang
1993 Volume 48 Issue 5 Pages
623-626
Published: 1993
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The report gives study results assessing the change in productivity of some staple food crops in Vietnam and assessing the influence and losses caused by climatic disturbances in agricultural production.
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Lucka Kajfez-Bogataj
1993 Volume 48 Issue 5 Pages
627-630
Published: 1993
Released on J-STAGE: March 16, 2010
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Slovenia is a mid-latitude country, where future climatic changes are expected to be significant. So, a dynamic crop model AGROS was used to examine combined effects of increasing CO
2 and higher temperatures on spring barley and maize yields in Slovenia. Model simulates water-limited production, but assumes healthy plants and appropriate nutrition. Simulations were carried out for various combinations of increased temperature (by 1, 2, 3, 4°C) and CO
2 concentrations (350, 450 and 700ppm). The model predicted shorter growing period due to warming for both crops. In spring barley the total dry matter and grain yield increase due to increasing CO
2, but if temperature rise exceeds 2.7°C, total dry matter and yield decrease. In maize the total dry matter, grain yield and harvest index generally increase.
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O. Ojo
1993 Volume 48 Issue 5 Pages
631-634
Published: 1993
Released on J-STAGE: March 16, 2010
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Global warming and climate change would significantly affect agriculture in West and Central Africa. Significant aspects of the possible effects would include (a) effects of increased rainfall and rising temperatures (b) effects of increased rainfall intensities and variability of rainfall (c) changes in agroclimatic and agroecological zones (d) effects on agricultural systems and (e) effects of the sea level rise. In general, the implications of climate change would reduce agricultural productivity and bring about poverty, hunger, famine and death to the local population.
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Y. Aono, Y. Omoto
1993 Volume 48 Issue 5 Pages
635-638
Published: 1993
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Changes in spring temperatures in Kyoto since the 14th century are estimated using flowering phenological data of cherry trees (
Prunus jamasakura, a native species) from old records. It is shown that flowering dates of cherry trees in Kyoto are closely related to the monthly mean temperature of March. This result is obtained using the so called DTS method, which has been used to estimate the first flowering date of P. yedoensis (a horticultural species). However, in this case it is applied to estimate the full flowering date of
P. jamasakura. It is shown that accuracy for both is almost the same. In this study, using this method with a reversed procedure, namely monthly temperatures for arch are estimated from full flowering dates. It is shown that for decadal means, calculated averaged March temperatures fell within 0.5°C from the actual value in the 20th century.
The result shows that there were relatively cold periods around the mid-14th, early 16th and late 17th through the early 19th centuries. There were warm springs during the early 17th century. A steady warming trend starting the early 19th century continuing to the present i s noteworthy. It is attributable to both urban warming and large scale warming.
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Shuqiu Wei, Guilian Liu
1993 Volume 48 Issue 5 Pages
639-641
Published: 1993
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This article systematically analyses the success and deficiencies of previous works. On the basis of this, the author of this article advances a method of using “The analogous distance of space dij” to measure the analogous degrees of climatic and agricultural climate among various places. The author also advances the calculation, concept and method of the analogy of distribution and slide. On the basis of research concerning climatic and bioclimatic analogy, the author puts forward the concept and method of bioclimatic analogy and according to all the above steps, establishes the ‘Computerized Information Consulting System for the Introduction of Organisms’.
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K. Kurata
1993 Volume 48 Issue 5 Pages
643-646
Published: 1993
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Variation of precipitation intervals at seven locations in Japan were compared with those of global surface air temperature and with those of the Japanese surface air temperature, using about a hundred years of daily precipitation data. Positive correlations between precipitation intervals and global or Japanese air temperature were found in many locations, suggesting that precipitation intervals will become longer with global warming in many parts of Japan.
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Defeng Zhu, Xichun Chen, Tichang Cai
1993 Volume 48 Issue 5 Pages
647-649
Published: 1993
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H. Sugaya
1993 Volume 48 Issue 5 Pages
651-654
Published: 1993
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A numerical model, based on the heat balance method, was developed to simulate snowpack evolution at a given location, as a function of meteorological conditions: air-temperature, wind speed, precipitation and incident short-wave radiation.
The model takes into account three major processes, (1) the increase in the amount of snowpack by precipitation, (2) melting of the surface snow layer as a result of energy balance and (3) drainage of water from the snowpack. The model was tested with data collected at TAKADA and NAGAOKA, JAPAN. The results show the ability of the model to simulate the day-to-day changes of the snow mass with reasonable accuracy. Emphasis was placed on the characteristics unique to this and other warmer climatic regions.
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Kazushige Yamada
1993 Volume 48 Issue 5 Pages
655-658
Published: 1993
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Special observations of solar radiation have been carried out in the northern side of central Japan. Using the data, Seasonal variation, geographical distribution and the relationship between solar radiation components and weather were obtained. The topographical features of the measurement stations were divided into two regions for solar radiation components.
The annual progression of total and direct solar radiation was characterized by a curve with two depressions in the rainy and snowy Seasons. The fraction of Photosynthetically Active Radiation (PAR, 395-715nm) in total solar radiation was large over in the Japan Sea region, though it was small over the the mountainous region.
The three atmospheric turbidity indices of Linke's turbidity factor, Tu, the mean extinction coefficient, a, and Berlyand's f-coefficient were estimated for clear days. Tu, a and f were slight in the the winter and large in the summer, and these values in the mountainous region were smaller than they were in the Japan Sea region. The relationships between precipitable water, three turbidity indices and PAR components were estimated by a simple proportional relation, respectively.
The effects of snow cover and clouds on total solar radiation were calculated. Under snow cover conditions, daily total solar radiation increased by about 10% on clear days and about 15-55% on cloudy days.
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Sarah Beatrice England
1993 Volume 48 Issue 5 Pages
659-662
Published: 1993
Released on J-STAGE: March 16, 2010
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Interviews carried out in Vietnam of local and national government officials as well as data from scientific institutions there reveal that Vietnam's forest policy emphasizes conservation and afforestation. The development of forested regions protects Vietnam against the effects of severe climatic events such as floods which are expected to increase in frequency if global warming progresses. Evidence of the seriousness of Vietnam's position is the ban of exports of round and cut logs which was instituted in early 1992. This is a brave move for a country short of foreign exchange and contrasts sharply with the policies of some of Vietnam's Southeast Asian neighbours. Approximately 75% of total inanimate energy comes from fuel wood and logs. Therefore, afforestation strategies involve rural people as paid custodians of tracts of forest, Sustainable harvesting of wood is allowed, while poaching of logs is effectively prevented. An increase in forest cover from 26% to 40% of Vietnam's territory is part of Vietnam's National Environment Action Plan, but future development of forest resources is constrained by a severe shortage of funds. In conclusion, Vietnam's commitment to forest development complements global efforts to preserve tropical rain forests, but will require substantial foreign aid.
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Shigeo Kobayashi
1993 Volume 48 Issue 5 Pages
663-666
Published: 1993
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Variations in forest structure, soil and microclimate were surveyed before and after harvesting. The logged-over forest degraded at the point of forest structure and soil condition. After that, natural regeneration can not be expected. However, microclimatic conditions at the open site which were created by selective cutting, were similar to a natural gap. Thus, “Forest Patch Improvement” and “Gap Planting” were proposed as rehabilitation methods for logged-over forests.
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Makio Kamichika, Tahei Yamamoto, Kyoichi Otsuki, Yasushi Abe
1993 Volume 48 Issue 5 Pages
667-669
Published: 1993
Released on J-STAGE: March 16, 2010
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This paper deals with saving water resources and improving irrigation water quality for agricultural development in arid areas. An experiment on the recycling use of irrigated water using earth-air heat exchange distillation is described.
The experimental apparatus is similar to a solar greenhouse using underground heat exchange. The air in the greenhouse which is nearly saturated by plant transpiration is refrigerated along the underground pipe and the vapour in it is condensed into waterdrops. The condensed water is collected. This recovered water is water distilled from the moist air, which is originally from irrigated water, and is available for re-use in irrigation.
The experiment was carried out in the vinyl film tunnel culture with lettuce plant. In the experiment, 30% of the supplied water was recovered. In addition to the re-use of this water, the vapor retentivity of the vinyl film can also result in a water savings of about 40% in comparison with open-field culture. Furthermore, it is expected that the accumulation of salt in soils can be reduced to about 40% compared with open-field culture conditions, because of the high quality of the distilled water which was recovered is mixed with irrigation water.
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Yoshinori Suzuki, Seiji Hayakawa, Hiroshi Hiiragi
1993 Volume 48 Issue 5 Pages
671-674
Published: 1993
Released on J-STAGE: March 16, 2010
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In agro-meteorological analyses of frost damage, a new device, namely, the thermal image analyzer, has been recently introduced. With the thermal image analyzer, we could confirm our results obtained by the usual meteorological observations. A new protecting method, a fog spray-freezing method, was tested and confirmed to be effective and high efficient in water consumption. When the air temperature was -1.8°C and -3.3°C, treated leaf temperature frozen with fog-particle was kept at-0.2°C under spray intensities of 0.4 and 0.6mm/hr, respectively. By comparison with the theoretical cooling capacity of the surrounding environment, this method is found to be highly efficient in water consumption because of it's high catching water ratio.
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Seiji HAYAKAWA, Yoshinori SUZUKI, Takuya MARUMOTO
1993 Volume 48 Issue 5 Pages
675-678
Published: 1993
Released on J-STAGE: March 16, 2010
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Differences in types of row cover can affect the microclimate under the row cover. The temperature at the soil surface and the air temperature between the row cover and soil depend on the physical characteristics of film mulch. Plant growth was more closely related to the accumulated effective soil temperature at a depth of 2.5cm than the accumulated effective temperature between the soil surface and row cover. The method of estimating the heat balance at the row cover is presented. Fairly reasonable agreement was obtained between the simulation experimental results and observations, and this helps to explain the characteristics of heat fluxes in the row cover.
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Kimio INOUE, Zenbei UCHIJIMA
1993 Volume 48 Issue 5 Pages
679-682
Published: 1993
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The sensitivity of canopy climate to the air's CO
2 level increment is investigated using a canopy flow model based on the mean turbulent field (MTF) closure models. Leaf processes in the model are highly parametrized using the experimental results obtained from the dependence of stomatal diffusion resistance on the CO
2 level. An increase in stomatal resistance with the CO
2-level was greater in C
4 plants (maize) than in C
3 plants (rice), indicating that changes in maize canopy climate are more significant than in rice canopy. In a model maize canopy, daily sensible heat loss increased along with CO
2 levels, with concomitant decreases in daily latentheatloss. Somewhat hotter and drier air conditions within maize canopies at higher CO
2-level are anticipated to be unfavorable for the growth and yield of maize crops.
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Taichi MAKI, Mingyuan DU, Borong PAN
1993 Volume 48 Issue 5 Pages
683-686
Published: 1993
Released on J-STAGE: March 16, 2010
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Dry land occupies one third of the total surface area of the world. The process of desertification has been accelerated recently by over-development, over-cultivation, over-deforestation, over-grazing and over-consumption of water. Wind erosion and sand accumulation due to strong dry winds are increasing due to lack of water, and agrometeorological disasters are apt to occur frequently in the marginal agricultural regions of the dry lands.
Meteorological observations related to the improvement of climatic conditions in aria lands were carried out at the Turfan Desert Research Station, Xinjiang Institute of Biology, Pedology and Desert Research located in the northwestern part of China from 1990 to 1992.
Under and conditions, we demonstrated that wind speed, air temperature, surface soil temperature and relative humidity could be improved, and wind also could be prevented by the use of a tamarisk forest windbreak with a density of 85% and a height of 4.6m in July, 1990, and by the construction of windbreak nets with densities of 45% and 50% and height of 1.85m in July and October, 1990, and May, August and November, 1991.
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Mingyuan DU, Taichi MAKI
1993 Volume 48 Issue 5 Pages
687-690
Published: 1993
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Functions, processes and effects of windbreak forests and windbreak nets for the prevention of drifting sands and desertification were studied by field experiments and observations at Turfan, Xinjiang, China and Tsukuba, Ibaraki, Japan. Results show that a single windbreak belt (forest or net) is effective for the prevention of drifting sands. However, sands can still flow through the belt, especially through the bottom of the belt due to the accelerated bleed there. Furthermore, sand dunes will form around the windbreak belt. Therefore, it is suggested that wide multi-windbreak belts including shrub and grass shelter belts, windbreak nets and forest shelter belts should be considered in the margin areas of oases and that a windbreak net might be the frontal and initial belt due to its easy setup and its benefits for vegetation growth.
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causes, processes, trends and harness
Tao Wang
1993 Volume 48 Issue 5 Pages
691-694
Published: 1993
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Arid and semi-arid regions occupy nearly half the area of China, where there are abundant natural resources and a great potential for development. However, these regions have been seriously troubled by sandy desertification which has become an important restricting factor for local development. On the basis of research and practice over many years, we believe that sandy desertification is environmental degradation indicated by wind erosion resulting from excessive human activities. The degraded land is desertified land. Between the important human and natural contributing factors, the former is the more crucial. The evolution of sandy desertification depends on the process of wind erosion after the ecosystem has been destroyed by humans, and its indicator is mainly presented by wind-erosion landforms. Sandy desertification leads to a rapid decline in the biomass production and the potential productivity of land, and even loss of land resources. The trend of sandy desertification will depend fundamentally on the human impact in coming decades. A number of typical examples have proved that the desertified land can be restored to its potential productivity for agriculture and animal husbandry through different harnessing measures.
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Hiroshi MATSUYAMA
1993 Volume 48 Issue 5 Pages
695-698
Published: 1993
Released on J-STAGE: March 16, 2010
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This study investigates the seasonal changes of evapotranspiration in the Amazon river basin during the FGGE period. The relationship between basin storage and evapotranspiration is also investigated. The atmospheric water balance method and that of the basin are used for the analysis, using the global objective analyzed data set, precipitation data and discharge data. Since the seasonal change pattern of precipitation shows good correspondence to that of water vapor flux convergence, monthly evapotranspiration remains almost constant within a year. On the other hand, the seasonal changes of basin storage are very great and it is concluded that evapotranspiration in the entire Amazon river basin is not affected by the seasonal changes of basin storage even in the dry season. It is also found that the role of evapotranspiration in the water cycle in the basin is relatively more important in the dry season than in the rainy season.
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N. Monji, M. Inoue, K. Hamotani, Y. Omoto
1993 Volume 48 Issue 5 Pages
699-702
Published: 1993
Released on J-STAGE: March 16, 2010
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Interaction between the atmosphere and a coniferous forest is examined based on a turbulence experiment. The daytime co-spectra of heat flux, water vapor flux and CO
2 flux are similar in shape. They have steeper however, when compared to co-spectra obtained over short plants, which means that turbulent transport occurs over a more limited range of eddies over a forest. The correlation coefficient between the vertical wind component and temperature or specific humidity is approximately 0.5 for unstable conditions, though that for CO
2 is less.
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T. Maitani, Y. Kashiwagi
1993 Volume 48 Issue 5 Pages
703-706
Published: 1993
Released on J-STAGE: March 16, 2010
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Characteristics of diurnal variations of sensible and latent heat fluxes above and within plant canopies were presented, using the data obtained by the eddy correlation method. The results show that the latent heat fluxes above plant canopies are much larger than those within plant canopies and that they are also much larger than sensible heat fluxes above plant canopies. The upper part of plant canopies contributes as a sink for sensible heat and a source of water vapor. The downward sensible heat fluxes could be readily observed in a paddy field. Model calculation shows that this may be caused by combinations of several factors such as lower insolation, higher air temperature, and higher wind speed.
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Masaki Shibata
1993 Volume 48 Issue 5 Pages
707-710
Published: 1993
Released on J-STAGE: March 16, 2010
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Relationships between dietary factors and methane production were investigated to predict total methane emission from livestock in Japan. Methane production differed with the type of diet. A high concentrate diet reduced methane production significantly. However, methane production per unit dry matter intake (DMI) was relatively constant. Therefore, Methane production by ruminants could be estimated adequately from DMI alone through 3 species of ruminants and various levels of feeding. From the results of regression analyses, annual methane emission from all livestock including ruminants, pigs and horses was estimated to be 0.35Tg/year in Japan.
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Yoshinobu HARAZONO, Schenggong Li, Janyou SHEN, Zhongyin He
1993 Volume 48 Issue 5 Pages
711-714
Published: 1993
Released on J-STAGE: March 16, 2010
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Field observations were carried out over grasslands facing desertification in a semi-arid area in China, then the micrometeorology was examined in relation to desertification. Albedo changed with grass growth, which reflects the surface conditions, wind profile over the grass was logarithmic though over the dune a turbulent mixing layer which prevents plant growth was dominant. Evapotranspiration of the grassland
ET was 2.8mm/day in early August, while it was less than 1mm/day in the dry season. Heat budget of the grassland facing desertification was close to that of the dune.
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Akira Miyata, Yoshinobu Harazono, Jianyou Shen, Shenggong Li
1993 Volume 48 Issue 5 Pages
715-718
Published: 1993
Released on J-STAGE: March 16, 2010
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Vertical transfer of momentum, water vapor and carbon dioxide over a dune and a grassland in a semi-arid area of China was measured by using eddy correlation techniques at the beginning of a dry season. The drag coefficient over the dune in the daytime under nearly neutral conditions was 18% of that over the grassland. Under unstable conditions, however, there was no clear correlation between friction velocity and horizontal wind speed over the dune. The diurnal averages of evapotranspiration rate and CO
2 assimilation rate at the grassland were 0.10mm/h and 0.43g/(m
2h), respectively. An upward transfer of water vapor was observed at the dune in the daytime, although the flux was smaller by an order of magnitude than that at the grassland.
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K. Minami, T. Kimura
1993 Volume 48 Issue 5 Pages
719-722
Published: 1993
Released on J-STAGE: March 16, 2010
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Presented here are measurements of methane (CH
4) uptake by, and nitrous oxide (N
2O) emissions from established grassland and neighboring forest-floor soils in Japan. Grassland and forest sods act as a sink of atmospheric CH
4 under aerobic conditions. From ours and other data, we estimated that the uptake of CH
4 by 14 ecosystem types throughout the world vary between 7 and 78 TgCH
4 per year. The sink strength of grasslands would represent a maximum of about 8.5% for the total CH
4 consumption by soil and other land uses.
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Hideyuki Shimizu, Yasumi Fujinuma, Kenzo Kubota, Tsumugu Totsuka, Kenj ...
1993 Volume 48 Issue 5 Pages
723-726
Published: 1993
Released on J-STAGE: March 16, 2010
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The impact of ozone (O
3) on the growth of several woody plants was investigated. Potted juvenile plants were exposed to 0.1ppm O
3 continuously for 3-4 weeks in artificially-lit growth cabinets. O
3 induced some visible symptoms and defoliation in many broadleaf trees, whereas no visible damage was observed with Japanese red cedar and momi fir. Shoot elongation growth of Japanese red cedar and China laurestine was suppressed remarkably by O
3, while growth of some broadleaf trees was accelerated in spite of defoliation. Thermal image analysis suggested that O
3 induced stomatal closure in some woody plants after 3 weeks of exposure. O
3 should be considered one causal factor of the “forest decline” observed throughout the world.
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Hideyuki Shimizu, Hwa-Seuk Ko, Kenzo Kubota, In-Sun Wui, Kenji Omasa
1993 Volume 48 Issue 5 Pages
727-730
Published: 1993
Released on J-STAGE: March 16, 2010
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The chronic effects of 0.1ppm O
3 on injury expression and growth in several herbaceous plant species were investigated. Two-week-old morning glory, radish and sunflower were exposed to 0.1ppm O
3 for 2 weeks in artificially-lit growth cabinets. Visible symptoms such as white fleck were revealed on leaves in these plants within 1-2 days, and the withering of old leaves was accelerated by O
3, especially in radish. Diffusive conductances of lower to middle leaves were more or less reduced by O
3. Dry weight growth in these plants was suppressed by O
3 after 2 weeks of exposure, especially in radish and sunflower. However, partitioning of dry matter was significantly affected by O
3 as observed in the lower root weight ratio (RWR) in O
3-exposed morning glory and radish. The possibility of good plant indicator systems for monitoring ambient atmosphere is also discussed.
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Isamu Nouchi
1993 Volume 48 Issue 5 Pages
731-734
Published: 1993
Released on J-STAGE: March 16, 2010
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Three cucumber cultivars (cv. Suyo, Shimoshirazu-jibaikyuuri and Tsukemidori) were grown for 3 weeks in sun-lit environmental glass chambers under UV-B (290-320nm) irradiation from six 20W fluorescent sunlamps using 0.10mm polyvinyl chloride sheeting and UV-B free control conditions using 0.10mm polyester film. Plants were irradiated with three levels (0, 244 and 381mW m
-2) of biologically effective UV-B (UV-B
BE) for 8h (8 a.m. to 4 p.m.) a day. The levels of UV-B
BE irradiance at Tsukuba (36°N latitude) were about 250mW m
-2 at noon in summer under clear sky conditions. Visible foliar injury (yellow lesions and glazing) due to UV-B irradiation occurred on the leaf surface. The leaf area and dry weight of whole plants of the three cultivars of cucumber were significantly reduced and decreased with increasing intensities of UV-B
BE irradiation. Growth parameters of the relative growth rate (RGR), the net assimilation rate (NAR) and leaf area ratio (LAR) were reduced by medium and high UV-B
BE irradiation throughout irradiation periods. Specific leaf area (SLA) decreased remarkably due to UV-B, which indicates that plants exposed to UV-B increase their leaf thickness. This increase of leaf thickness might be an adaptation mechanism against increased UV-B radiation.
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H. Hara
1993 Volume 48 Issue 5 Pages
735-738
Published: 1993
Released on J-STAGE: March 16, 2010
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Precipitation chemistry in Japan was discussed based on a wet-only event-basis dataset from five sites from April 1984 to March 1988. The annual average pH at each site ranged from pH4.5 to 5.1. Non-seasalt (nss-) sulfate and nitrate concentrations ranged from 30 to 63μmol/L and from 19 to 79μmol/L, respectively. The pH was higher for the concentration levels of nss-sulfate and nitrate. This was attributable to the probable neutralization of the input acidity by additonal alkaline species, gaseous ammonia and particulate calcium species. This was discussed in terms of pH and pAi defined as -log ([nss-SO4
2-]+[NO3
-]).
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Yumiko Tanaka
1993 Volume 48 Issue 5 Pages
739-742
Published: 1993
Released on J-STAGE: March 16, 2010
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Sensible heat flux is measured using the eddy-correlation method in a deciduous forest.
Estimates of sensible heat flux are found to compensate for most of the heat loss caused by negative net long wave radiation in the afternoon on the snow surface under calm conditions in mid winter. Twenty four hour total heat balance components show that the conductive heat flux from the snow cover occupies 87 to 100% of the net radiation. Sensible heat flux is found to be less than 6% of the net radiation, though it plays an important role in compensating for the daily maximum of difference between air temperature and snow surface temperature during the first 2-3 hours after the net long wave radiation turns negative at 14:00. The Ri number which indicates the criterion for stability achieves a maximum value of 0.1 at 1.5:00-19:00. The turbulent air flow on the snow surface is characterized as intermittent and low turbulent under stable conditions. The sensible heat flux fits the one obtained under strong stable conditions, by using the empirical constant K in the empirical equation known as the bulk method. Power spectra for the vertical, streamwise wind velocity and temperature computed by the Maximum Entropy Method show low spectral density under strong stable conditions.
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Tatsuo Hosono, Isamu Nouchi
1993 Volume 48 Issue 5 Pages
743-746
Published: 1993
Released on J-STAGE: March 16, 2010
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Three species of crops, radish, spinach and bush bean, were exposed to simulated acid rain at pH 5.6 (control) to 2.5 throughout their growing periods. Plants were subjected to acid rain treatment three times a week, for one hour with 10mm of precipitation at a time. All the plants exposed to simulated acid rain falls at pH3.0 or below produced visible injury on the leaves. The visible injuries were severe on the cotyledons of radish and spinach and primary leaves of bush bean exposed to rain at pH 2.7 and 2.5, which resulted in the growth reduction of plants at early stages of growth compared to pH 5.6. In none of the cases in this study did treatment at pH 3.0 or higher significantly affect the growth of leaf area or dry weight of whole plants in three species. These results suggest that current ambient levels of rain acidity in Japan, where annual mean pH value is about 4.6, may not affect growth in the three species of crops tested in this study.
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