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Predicting the effects of climate change on the vadose zone is a new and important application of the analysis of simultaneous heat and water movement between the atmosphere and the vadose zone. The HYDRUS-1D software system, with meteorological submodels that evaluate the surface water and energy balance, has been reported to be a useful tool for predicting field thermal and moisture conditions in semiarid regions. Application of the physical model to a humid climate and all types of soils is necessary because this climate has pronounced biological activity and thus significantly contributes to the global environment. The purpose of this study was to evaluate the usefulness of HYDRUS in predicting annual changes in soil moisture and temperature in the vadose zone under a monsoon climate. The model was evaluated using observed data from a western suburb of Tokyo. The soil properties utilized in the simulation were obtained using laboratory experiments. Climate data for the meteorological submodels were obtained from open-access climate records. The observed surface heat flux agreed well with the predicted surface heat flux produced by the meteorological submodels. The numerical results produced by HYDRUS using the meteorological submodels represented annual changes in soil thermal and moisture conditions fairly well. Our results show that the meteorological submodels of HYDRUS are appropriate to produce thermal and water boundary conditions under a monsoon climate. This suggests that HYDRUS has the potential to simulate the physical conditions of the vadose zone by using forecast climate data coupled with global circulation models.

Water-saving rice-winter crop rotation systems were repeated for 4 cycles from 2000 to 2004 in an urban area, Nishitokyo, Japan, to assess the effects of water-saving (i.e. non-flooded vs. flooded) on grain yield of rice (Oryza sativa L.) and chemical constituents of percolating water. The effects of pre-rice winter cropping compared with fallow on rice yield were also examined. The pre-cultivated crops were wheat (Triticum aestivum L.), italian ryegrass (Lolium multiflorum Lam.) or spinach (Spinacea oleracea L.) with their above-ground parts removed, chinese milk vetch (Astragalus sinicus L.) or rapeseed (Brassica napus L.) with their above-ground parts incorporated before rice transplanting. Neither winter cropping effects nor its interaction with water-saving were significant for rice yield, although the yield after rapeseed incorporation tended to be 9 % higher than that after fallow. In 2001, 2003 and 2004, when more than 70% of irrigation water was saved in the non-flooded trial, average yield in non-flooded trial was 58 % of flooded trial, but water productivity increased (from 0.10 to 0.16 kg m-3). Among the 3 years, yield in non-flooded trial was highest in 2004 when the amounts of irrigation and total water supply was larger, the frequency of dry spells was the lowest, and 2 seedlings were transplanted per hill. The nitrate and nitrite concentrations in the percolating water were far below the environmental standard values by WHO. The study showed that incorporation of winter crops had no negative effects on water-saving rice production at least for the first 4 years, and that under extreme water-saving, irrigation and planting methods could minimize yield reduction.

A Deep Root System May Be A Desirable Plant Characteristic In Upland Rice Because It Improves The Plant’s Water Extraction Capacity. The Objective of The Present Study Was To Assess The Deep Root Development of Rice Cultivars In Relation To Soil Moisture Change and Plant Water Status Under Upland Conditions With Moderate Water Deficits In The Field and In Simple Lysimeter Experiments. We Used One Upland Cultivar (‘Yumeno-Hatamochi [Yhm]) and Two Lowland Cultivars (‘Lemont’ [Lmt] and 'Nipponbare’ [Npb]) In The Field Experiment, With No Supplemental Water From 88 To 106 Days After Sowing (Das) and 116 To 145 Das. In The Lysimeter Experiment, We Used Yhm and Npb and Imposed Two Water Stress Periods During The Late Vegetative Stages (71 To 104 Das and 88 To 104 Das). In The Lysimeter Experiment, A Higher Deep-Root Length Ratio (Proportion of The Length of Deep Roots To The Total Root Length) In Yhm Was Associated With A Greater Deep-Root Length Than In Npb. The Difference In Deep Root Development Was Associated With Change In Soil Water Content At The Depths of 45 To 70 Cm Between The Two Cultivars Under The Above Conditions. The Drought In The Field Experiment Was Less Intense Than In The Lysimeter Experiment, and We Observed Greater Varietal Differences In Total Aboveground Biomass Than In Root System Development; This Was Associated With The Change In Soil Water Content During The Initial Drought Period. Lmt, With Smaller Shoots, Tended To Save Water and Maintain Higher Leaf Water Potential and Lower Diffusion Resistance As The Drought Progressed. Our Results Suggest That Deep Root Development of Rice Was Primarily Advantageous For Soil Water Extraction and Plant Water Status Under Moderate Water Stress In Uplands, But That The Advantage of A Deep Root System Was Affected By Total Aboveground Biomass, Which Had Strong Effects On Plant Water Status Under These Conditions.

Wedge-shaped defects are frequently observed on the cervical region of the human tooth. Previously, most studies explained that improper toothbrushing causes such defects. However, recent clinical obsarvation suggested that the repeated stress due to occlusal force may induce the formation of these wedge-shaped defects. In this study, a two-dimensional human tooth model after a wedge-shaped defect is restored with the composite resin is analyzed by using the finite element method. To obtain the intensity of the singular stress field accurately, a method of analysis is discussed for calculating generalized stress intensity factors, which control the singular stress around the tip of the defect. Then, the relationships between the stress intensity and occlusion are discussed.