Japanese Andisol Research Articles

Effects of dissolved organic matter on soil aggregate dynamics using rare earth oxides as tracers in A Japanese Andisol

Effects of dissolved organic matter on soil aggregate dynamics using rare earth oxides as tracers in A Japanese Andisol

Can endophyte-infected tall fescue minimize the grass tetany risk?

Non-toxic Neotyphodium (novel endophyte) has been shown to provide similar agronomic performance as wild-type endophyte to deter pathogens without exerting adverse effects on livestock. While the grass/novel endophyte interaction does not synthesize alkaloid peramine that has been linked to mammal toxicity, the connection between wild (naturally occurring) and/or novel endophyte infection and tetany ratio in forage has not been evaluated. The risk of grass tetany was evaluated in naturally occurring endophyte-infected tall fescue grass grown in Japanese Andisol. Three tall fescue (Festuca arundinacea Schreb.) ecotypes (Fukaura, Koiwai and Showa) either infected with Neotyphodium coenophialum (Morgan-Jones and Gams) Glenn, Bacon and Hanlin (E+), or noninfected (E-) were grown in low phosphorus (P) availability black Andisol and high P availability red Andisol under a controlled environment. The biomass nutrient concentration was measured and the tetany ratio, K/(Ca+Mg), was established for all three fescue ecotypes. 
 Results showed that K, Ca, and Mg concentrations and the K/(Ca+Mg) were significantly affected by endophytes, soils, and ecotypes and their interactions. Regardless of ecotypes and soils, K, Ca, and Mg concentrations were higher in endophyte-infected plants when compared to the control. Among the endophyte-infected ecotypes, the Fukaura and Koiwai showed higher K, Ca, and Mg concentrations in red Andisol. In contrast, the Showa ecotype showed higher K, Ca, and Mg concentrations in endophyte-infected plants than the control in black Andisol. Notwithstanding ecotypes and soils, endophyte-infected plants showed lower K/(Ca+Mg) than their counterparts, suggesting that the grass/endophyte interaction could provide a means of reducing the incidence of grass tetany in livestock.

Do High-Magnesium Cool-Season Grasses Contemplate Grass Tetany Risk?

Economic losses associated with grass tetany either of death or poor growth performance of livestock are a growing concern. Breeding of high magnesium (high-Mg) cool-season forage grass (C3) has been a challenging process to minimize the hazards of grass tetany. For appraising the breeding of high Mg-containing cultivars in Japanese Andisol, agronomic properties and grass tetany risk of high-Mg cultivars were compared with commercial cultivars. The high-Mg cultivars of Italian ryegrass (Lolium multiflorum L.), tall fescue (Festuca arundinacea Schreb.), and orchardgrass (Dactylis glomerata L.) were “Magnet”, “HiMag” and “Mgwell”, respectively. The commercial cultivars were viz., Ace, Tachiwase, and Waseyutaka of Italian ryegrass, Hokuryo, Kentucky-31 (Ky-31), and Fawn of tall fescue, and Akimidori and Okamidori of orchardgrass, respectively. Grasses were grown in temperate Andisol under field conditions with standard management practices and were harvested four times during the year. The average plant heights of the high-Mg containing cultivars were lower than the commercial cultivars with the relative range of −7.4%, −3.7%, and −1.5% for Italian ryegrass, tall fescue, and orchard grass species, respectively. The seasonal yield of high-Mg cultivars was ranked as Magnet > HiMag > Mgwell. The Mgwell orchard grass had lower potassium (K) content compared with their respective commercial cultivars with a relative range of −2.2%. Across four harvests, a significantly higher calcium (Ca) and magnesium (Mg) content, and lower grass tetany potential were recorded in high-Mg cultivars when compared to commercial cultivars, irrespective of species. Across four harvests, the lowest grass tetany index, [K/(Ca + Mg)] of 1.36 was recorded in Mgwell orchard grass. The high-Mg cultivars showed the lowest [K/(Ca + Mg)] across four harvests compared to commercial cultivars, promoting the effectiveness of breeding cool-season grass species to control grass tetany in temperate regions (Andisol) and climatic conditions.

Aspect of the degradation and adsorption kinetics of atrazine and metolachlor in andisol soil

Summary The degradation kinetics and sorption characteristics of atrazine and metolachlor in Japanese andisol soil were evaluated using laboratory incubation of soil samples. The water content of the soil was set to field capacity while three different temperatures (5, 25 and 35°C) were considered for the experiment. First order model fitted the degradation kinetics of both herbicides under the investigated temperature range with half-lives ranging from 19.2 to 46.9 days for atrazine and from 23.4 to 66.9 days for metolachlor, respectively. The activation energies (Ea) of atrazine and metolachlor calculated using Arhenius equation were 21.47 and 23.91 kJ mol−1, respectively. The soil sorption study was conducted using the batch equilibrium process. The adsorption behaviors of atrazine and metolachlor were investigated using linear, Freundlich and Langmuir isotherms although the linear and Freundlich isotherms gave relatively high correlation coefficient (R2 ) and very low standard error of estimate (SEE). The free energy (ΔG°) values were in the range −30.6 to −32.0 kJ/mol, and −32.1 to −41.5 kJ/mol for atrazine and metolachlor, respectively. Thermodynamic parameters indicated that the adsorption is spontaneous, endothermic accompanied by increase in entropy. The understanding of atrazine and metolachlor sorption processes is essential to determine the pesticide fate and availability in soil for pest control, biodegradation, runoff and leaching.

Anisotropy of Transport Properties of a Remolded, Compacted Andisol

The transport properties of soil gas and water are known to be anisotropic in undisturbed field samples. However, little is known about the same in remolded samples that resemble the field condition after plowing. Moreover, the effect of added fresh organic matter (OM) on the anisotropy has attracted little attention. In this study, rice (Oryza sativa L.) husks and rice straw were added to a Japanese Andisol. These samples and those with no added fresh OM were remolded and compacted at 225 kPa. The saturated hydraulic conductivity (Kₛ), relative gas diffusivity [(Dₚ/D₀)₁₀₀], and air permeability (kₐ₁₀₀) at −100 hPa matric potential were measured in the vertical and horizontal directions. These values were then used to calculate the specific hydraulic conductivity (SKₛ), specific gas diffusivity (SD₁₀₀), and specific air permeability (Sₖₐ₁₀₀). The vertical (Dₚ/D₀)₁₀₀, kₐ₁₀₀, and Kₛ values were significantly higher than the horizontal values, suggesting anisotropic gas and water flows. Larger pores were arranged anisotropically based on the higher SD₁₀₀, Sₖₐ₁₀₀, and SKₛ in the vertical than in the horizontal direction. The rice husks improved the horizontal gas flow, and the rice straw impeded the vertical gas flow. Both of these OMs aligned horizontally and improved the horizontal water flow. The results of this study suggest that the anisotropy of the remolded, compacted samples may be different from that of the intact samples. Thus, further studies on a range of soil types using both disturbed and undisturbed samples need to be conducted to test the generality of this result.

Degradation profile of azoxystrobin in Andisol soil: laboratory incubation

The fate of azoxystrobin in soil under the effect of different temperature is of interest because application directions specify soil-surface treatments for number of agricultural pests. Temperature is an important factor governing the rate of degradation in soil pore. The purpose of this investigation was to understand better the effect of temperature on the degradation of azoxystrobin in Japanese Andisol soil. This was done through laboratory incubation of soil at three different temperatures (5 °C, 20 °C, 35 °C). First-order kinetics could be used to describe degradation of azoxystrobin under controlled condition of temperature (r2 ˃ 94). The results showed that, during the 120-day incubation period for azoxystrobin, 64%, 70%, and 78% of applied azoxystrobin were degraded at 5 °C, 20 °C, and 35 °C, respectively. By using the Arrhenius equation, the activation energy of degradation of azoxystrobin fungicide was calculated (7.48 ± 1.74 kJ mol−1) in soils, which confirm that temperature had a significant influence on the degradation rate. Q10 value of 1.11, for azoxystrobin, indicated that the response of fungicide dissipation to temperature was large. For azoxystrobin, there was a much larger difference in dissipation rates at 5 °C and 35 °C, indicating that biological and/or chemical degradation of azoxystrobin may have nearly reached its optimum at 35 °C.

Surface Hydrophobicity of Japanese Andisol and its Behavior upon Exposure to Heat

It has long been established that heating, whether in situ or in the laboratory, can influence the hydrophobicity of soils. The objective of this study was to examine the surface hydrophobicity of Japanese Andisol and its behavior upon exposure to heat, considering the effect of heat at different levels of hydrophobicities, using natural and hydrophobized [with stearic acid (SA)] arable surface soil. For this purpose, samples were provided with two conditions: (i) kept at 25°C and 75% relative humidity, and (ii) exposed to 50°C for 5 h d−1 over a period of 40 d and the remaining time at 25°C and 75% relative humidity. Hydrophobicity was determined using contact angle and water drop penetration time (WDPT) measurements. Unhydrophobized samples exposed to 50°C showed 15% increment in contact angles and significant increment in WDPTs compared with those exposed to 25°C. In contrast, samples with 5 g kg−1 SA exposed to 50°C showed a 3.5% decrease in contact angles and substantial decrease in WDPTs compared with those kept at 25°C. The WDPT of these samples (5 g kg−1 SA) decreased from >3600 s at 25°C to values as low as about 2 s at 50°C, irrespective of the high contact angle (>100° at both 25 and 50°C). This was attributed to the formation of hydrophilic salts of SA due to heat and to the specific physical characteristics of Japanese Andisols, especially to the high porosity.

Water stable aggregates of Japanese Andisol as affected by hydrophobicity and drying temperature

Abstract Hydrophobicity is a property of soils that reduces their affinity for water, which may help impeding the pressure build-up within aggregates, and reducing aggregate disruption. The purpose of this study was to examine the relation of soil hydrophobicity and drying temperature to water stability of aggregates while preventing the floating of dry aggregates using unhydrophobized and hydrophobized surface Andisol. Soil was hydrophobized using stearic acid into different hydrophobicities. Hydrophobicity was determined using sessile drop contact angle and water drop penetration time (WDPT). Water stability of aggregates (%WSA) was determined using artificially prepared model aggregates. The %WSA increased as the contact angle and WDPT increased. Contact angle and WDPT, which provided maximum %WSA showing less than 1 s of floating, was around 100° and 5 s, respectively. Although the %WSA gradually increased with increasing contact angle and WDPT above this level, high levels of hydrophobicity initiated aggregate floating, which would cause undesirable effects of water repellency. Heating at 50°C for 5 h d-1 significantly affected %WSA and hydrophobicity in hydrophobized samples, but did not in unhydrophobized samples. The results indicate that the contact angle and wetting rate (WDPT) are closely related with the water stability of aggregates. The results further confirm that high levels of hydrophobicities induce aggregate floating, and the drying temperature has differential effects on hydrophobicity and aggregate stability depending on the hydrophobic materials present in the soil.

Soil-water contact angle as affected by the aqueous electrolyte concentration

Electrolyte concentration changes the surface tension of the water-air interface, which is expected to affect the solid-water contact angle. In the present study, we focused on examining the effects of aqueous electrolyte concentration on the contact angle of soil samples with different hydrophobicities using sodium chloride (NaCl) and calcium chloride (CaCl2) solutions. Japanese Andisol and silica sand were hydrophobized using stearic acid to obtain different hydrophobicities. The contact angle of all the samples increased with increasing electrolyte concentration. This was attributed to the increasing surface tension of the solutions. The response of contact angle to the electrolyte concentration was positively correlated with soil surface free energy fitting into a linear relationship in Andisol, but not in silica sand. Surface tension of electrolyte solutions increases linearly with electrolyte concentration up to high salinities, and the contact angle can be expected to increase with increasing electrolyte concentration in a corresponding pattern. The relationship observed in the present study was non-linear, where more prominent increase of contact angle was observed at low electrolyte concentrations. The response of contact angle to the increasing electrolyte concentration was almost negligible at concentrations higher than 0.06 mol L−1, [ionic strength (I): 0.06 mol L−1] for NaCl, and 0.1 mol L−1, (I: 0.3 mol L−1) for CaCl2 solutions. The lowered solid-liquid interfacial free energy and its effects on contact angle with increasing adsorption of ions at the interface was considered to be the reason for decreasing slopes of the curves. Initial increase in contact angle with increasing ionic strength of CaCl2 was lower than that of NaCl. This might be because the adsorption of ions on soil surfaces, and the consequent effects on lowering the free energy of the solid-liquid interface and the contact angle, are more pronounced for calcium ions (Ca2+) than for sodium ions (Na+).

On Mapping Surface Moisture Content of Japanese Andisol Using GPR

Ground penetrating radar (GPR) ground wave was used to monitor the surface soil-moisture content distributions at a natural Japanese Andiol (i.e., Kanto loam) site. The study site was maintained as bare during three month monitoring period. The results obtained from ground wave analysis showed non-uniformity in moisture content distribution. However the zones of higher moisture content were found at similar locations among different times, with or without precipitation events between observation times. This indicates that surface soil moisture dynamics are more-or-less location (i.e., topography, soil physical properties) dependent. Our study highlighted the use of GPR ground wave as a skillful way to execute noninvasive moisture content mapping of Japanese Andisol.

Abstracts of Nippon Dojo-Hiryogaku Zasshi

Abstracts of Nippon Dojo-Hiryogaku Zasshi

Dynamics of Microbial Community in Japanese Andisol of Apple Orchard Production Systems

In this study, two fields of temperate Andisols from high‐input and low‐input (zero‐input) management practices of an apple orchard were selected to assess microbial community dynamics based on environmental variables. Soils from an Ap horizon were sampled in five consecutive months from May to September and assessed for phospholipid fatty acids as a biomarker of soil microbial community, soil hardness, bulk density, porosity, pH, electrical conductivity (EC), organic carbon (C), available nitrogen (N) and phosphorus (P), and exchangeable cations as soil environmental variables. For all sample dates, total phospholipid fatty acids (PLFAs), total bacterial PLFAs, fungal PLFA, mycorrhizal PLFA, PLFA for actinomycetes, and earthworm were higher in low‐input management than high‐input management. Total PLFAs showed a high degree of seasonality, having August maxima and May minima. Significant effect on the relationships among soil environmental variables and microbiological attributes were observed. Soil management practices also showed a remarkable effect on the relationships among microbiological traits, indicating that some mechanism regulated soil microbial dynamics under two soil management practices. Comparatively higher correlations among the microbiological attributes were observed in low‐input management than high‐input management. Irrespective of soil management practices, bacterial and fungal lipid biomarkers were negatively correlated, suggesting that these subsets of fatty acids are contrasting components of the microbial biomass. Bulk density has negative influence on all soil microbial communities except fungi. On the other hand, linoleic acid and organic C were positively correlated, referring to the distribution of soil organic C implying an upper layer of soils. Microbial community composition and structure were greatly affected by sampling date and to a lesser extent by long‐term management practice. In this study, both ecosystems were characterized by a very diverse microbial community.

Deep‐Soil Adsorption of Nitrate in a Japanese Andisol in Response to Different Nitrogen Sources

Nitrate adsorption in a deep Andisol with a high anion exchange capacity (AEC) needs to be studied for groundwater management. We evaluated N balances and content profiles under cropping in Andisol fields after 10 yr of repeated N additions of different N sources—swine compost (SC, N application rate of 800 kg ha−1 yr−1), coated urea (CU, 400 kg ha−1 yr−1), or NH4–N (AN, 400 kg ha−1 yr−1)—and an unfertilized control (NF). The N losses from the 0‐ to 20‐cm layer of three N‐treated soils during the experiment were 2300 to 2700 kg N ha−1, which were not significantly different (P > 0.05). Nitrate‐N retention in deep‐soil profiles up to 450 cm was 1800 to 2300 kg N ha−1 irrespective of N source (P > 0.05), and was 788 kg ha−1 in the NF treatment. On the other hand, the type of N source affected soil content profiles: from the two types of slow‐release N additions (SC and CU) remained within a depth of 60 cm, whereas in the 180‐ to 280‐cm layer was significantly higher in the AN treatment (P < 0.05). Stepwise multiple regression analysis showed that the primary contributor to soil content was Al content derived from allophane and imogolite, followed by soil pH and with negative impacts. In Andisols of Ibaraki, Japan, leached from the root zones is retained by adsorption in deep layers, which may reduce the risk of groundwater contamination at least for 10 yr.

NO, N 2O, CH 4 and CO 2 fluxes in winter barley field of Japanese Andisol as affected by N fertilizer management

The study was carried out at the experimental station of the Japan International Research Center for Agricultural Sciences to investigate gas fluxes from a Japanese Andisol under different N fertilizer managements: CD, a deep application (8 cm) of the controlled release urea; UD, a deep application (8 cm) of the conventional urea; US, a surface application of the conventional urea; and a control, without any N application. NO, N 2O, CH 4 and CO 2 fluxes were measured simultaneously in a winter barley field under the maize/barley rotation. The fluxes of NO and N 2O from the control were very low, and N fertilization increased the emissions of NO and N 2O. NO and N 2O from N fertilization treatments showed different emission patterns: significant NO emissions but low N 2O emissions in the winter season, and low NO emissions but significant N 2O emissions during the short period of barley growth in the spring season. The controlled release of the N fertilizer decreased the total NO emissions, while a deep application increased the total N 2O emissions. Fertilizer-derived NO–N and N 2O–N from the treatments CD, UD and US accounted for 0.20±0.07%, 0.71±0.15%, 0.62±0.04%, and 0.52±0.04%, 0.50±0.09%, 0.35±0.03%, of the applied N, respectively, during the barley season. CH 4 fluxes from the control were negative on most sampling dates, and its net soil uptake was 33±7.1 mg m −2 during the barley season. The application of the N fertilizer decreased the uptake of atmospheric CH 4 and resulted in positive emissions from the soil. CO 2 fluxes were very low in the early period of crop growth while higher emissions were observed in the spring season. The N fertilization generally increased the direct CO 2 emissions from the soil. N 2O, CH 4 and CO 2 fluxes were positively correlated ( P<0.01) with each other, whereas NO and CO 2 fluxes were negatively correlated ( P<0.05). The N fertilization increased soil-derived global warming potential (GWP) significantly in the barley season. The net GWP was calculated by subtracting the plant-fixed atmospheric CO 2 stored in its aboveground parts from the soil-derived GWP in CO 2 equivalent. The net GWP from the CD, UD, US and the control were all negative at −243±30.7, −257±28.4, −227±6.6 and −143±9.7 g C m −2 in CO 2 equivalent, respectively, in the barley season.

Soil microbial biomass and activities in a Japanese Andisol as affected by controlled release and application depth of urea

This experiment was conducted in maize field plots to study the effects of controlled release and application depth of urea on soil microbial biomass and activities at two depths of surface soil of a Japanese Andisol from June to September, 2001. Three N amendment treatments and a Control were included in this experiment: deep application (8 cm) of controlled release urea; deep application (8 cm) of conventional urea; surface application of conventional urea; Control, without N application. Prior to this experiment, the field plots received the same N fertilizer treatments for two consecutive years under maize/barley rotation. Soil microbial biomass, dehydrogenase and nitrification activities exhibited great vertical and temporal variations during the maize growth season, and the microbial biomass was significantly correlated to soil water-filled pore space (p<0.01). N fertilization did not significantly affect the microbial biomass, but greatly increased the dehydrogenase and nitrification activities. The increase in the microbial activities following N fertilization was not attributed to the increase in microbial biomass but to the increase in intrinsic microbial activities. Controlled release urea was found to continuously affect the dehydrogenase activity over a shorter distance, while conventional urea could greatly increase the enzyme activity for a shorter period of time. Both controlled release and deep application of urea had potentials to reduce the nitrification activity and suggested that the nitrate production might be decreased in 0–10 cm surface soil. Deep application of urea increased aboveground N uptake by maize and then the recovery rate of N fertilizer, whereas controlled release of urea greatly increased grain yield and N uptake by grain.

Nitrogen oxide emissions and soil microbial activities in a Japanese andisol as affected by N-fertilizer management

This experiment was conducted in maize field plots to study the effects of N-fertilizer management on nitrogen oxide emissions, soil microbial activities and crop yield, and the relationships among them in a Japanese Andisol. N fertilization increased both nitrification and dehydrogenase activities in soil and the emissions of NO and N20. Nitrification and dehydrogenase activities showed a close relationship with the NO emission, while the relationship with the N20 emission was not significant. Deep application (8 cm) of N fertilizer generally decreased both nitrification activity and NO emission. Controlled release of N fertilizer decreased the dehydrogenase activity and up to 86% of the NO emission. Our findings indicate the possibility that the low biological NO production in soil by deep application and controlled release of N fertilizer contributed to the low NO emission. Application of controlled release N fertilizer significantly increased the grain yield and N uptake by grain. NO emission showed a negative relationship with maize yield as affected by N-fertilizer management, suggesting the possibility of mitigating NO emission from Andisols without reducing crop production.

Effect of organic matter application on N2O, NO, and NO2 fluxes from an Andisol field

We used an automated flux monitoring system to measure N2O, NO, and NO2 fluxes from an Andisol field between May 1999 and September 2000. Pac choi and spinach were cultivated for 1.5 months in 1999 and 2000, respectively. We applied 15 g N m−2 of oilcake, cattle manure, fishmeal, dried cattle excreta, or urea to each plot. N2O and NO emissions from organic plots over the cultivation period were 2.55 mg N m−2 to 35.2 mg N m−2, and 2.48 mg N m−2 to 22.5 mg N m−2, respectively. Those from the urea plot were 10.9 mg N m−2 to 21.1 mg N m−2, and 52.0 mg N m−2 to 105 mg N m−2, respectively. We estimated that N2O emission from organic fertilizer is equivalent to that from chemical fertilizer application on Japanese Andisol field.

Nitrous oxide concentrations in an Andisol profile and emissions to the atmosphere as influenced by the application of nitrogen fertilizers and manure

A field experiment was conducted to determine N2O concentrations in the soil profile and emissions as influenced by the application of N fertilizers and manure in a typical Japanese Andisol, which had been under a rotation of oat and carrot for the previous 3 years. The treatments include ammonium sulphate (AS), controlled-release fertilizer (CRF) and cattle manure (CM) in addition to a control; all the fertilizers were applied either at 150 kg N ha–1 or 300 kg N ha–1 at the time of sowing carrot. N2O emissions from the soil surface were measured with closed-chamber techniques, while N2O concentrations in the soil profile were measured using stainless steel sampling probes inserted into the soil at depths of 10, 20, 40, 60, 80 and 100 cm. Moreover, soil water potential, soil temperature and rainfall data were also recorded. The results indicated that N2O concentrations in the soil profile were always greater than in the atmosphere, ranging from 0.36 µl N2O-N l–1 to 5.3 µl N2O-N l–1. The relatively large accumulation of N2O in the lower profiles may be a significant source for N2O flux. Taking the changes of soil mineral N into consideration, most emissions of N2O were probably produced from nitrification. The accumulation of N2O in the soil profile and emissions to the atmosphere were differently influenced by the amendments of N fertilizers and manure, being consistently higher in CRF than in CM and AS treatments at the corresponding application rates, but no significant difference existed with respect to the various N sources.

Seasonal variations in soil microbial biomass content and soil neutral sugar composition in grassland in the Japanese Temperate Zone

We investigated seasonal variations in the soil microbial biomass N content (MBN) and the soil neutral sugar composition from April 1995 to September 1996 in cattle-grazed pasture in a Japanese Andisol. MBN showed seasonal variation, gradually increasing from April to August, and decreasing rapidly by the end of August when soil moisture content decreased. Soil inorganic-N increased after fertilization and cattle pasturage. Seasonal variations in seven types of neutral sugar-C contents in the soil were observed. However, the trends in seasonal variation for sugars derived from plant materials were different from one another and from those derived from microbial products. Seasonal variation trends in soil neutral sugar-C were similar to that of MBN, with a sharp decrease in midsummer and a subsequent increase in autumn probably due to dence pasture plant growth. Furthermore, galactose-C (Gal), rhamnose-C (Rham) and ribose-C (Rib) that originated mainly from microbes showed positive correlations with MBN, but the other forms of soil neutral sugar-C did not. It was concluded that the composition of the soil organic matter accumulated in grassland varied seasonally, and that these seasonal variations can be investigated by MBN or by soil neutral sugar composition.