Abstracts of nippon Dozyohiryogaku Zasshi

Aluminum toxicity and boron deficiency are the major factors that limit plant growth and development in acid soils and in B-deficient soils. Root growth inhibition is an early symptom of AI toxicity and B deficiency. Effects of AI and B supply and their interaction on the growth of wheat (Triticum aestivum L.) seedlings were investigated using hydroponics. Fifteen wheat cultivars commonly grown in Bangladesh were used and found to differ considerably in their tolerance to AI toxicity and B deficiency. The relative root length of all the wheat cultivars at 50 µM AI (pH 4.5) ranged from 27 to 71% relative to the control (0 µM AI). Among the cultivars, Inia66 and Kalyansona were found to be the most Al-tolerant and sensitive cultivars, respectively, based on the data of relative root length, malate exudation and AI content of roots. Malate was detected in all the cultivars in the presence of 100 µM AI (pH 4.3). Inia66 exuded a 6-fold larger amount of malate and the AI content of roots was 4 times lower than that in Kalyansona. The vigorous seedling growth was observed at 40 µM B among the series of B treatments. Considerable cultivar differences in response to 40 µM B were observed among the 15 cultivars. Kalyansona was considered to be the most sensitive and Kheri the most tolerant to B deficiency. The interaction effects of B ( 40 and 200 µM) and AI (50 µM) on seedling growth were also examined in Inia66 and Kalyansona. Root growth was inhibited in the presence of Al but B supply especially at 200 µM B in the Kalyansona cultivar caused a slight improvement.     

Abstracts of Nippon Dojohiryogaku Zassui

The effects of NO₂ and O₃ exposure alone or in combination were investigated with respect to the amino acid content and composition in kidney bean. The short-term exposure (up to 8 h) to NO₂ at a concentration of 4.0 ppm alone or in combination with O₃ at a concentration of 0.4 ppm induced a rapid increase in the total amino acid content among which glutamine accounted for most of the part. Total amino acid content was also increased by O₃ exposure at 0.4 ppm after 2 hours’ lag period. Ammonium level became higher in the case of combined exposure to NO₂ and O₃, while it remained constant in the case of exposure to NO₂ and O₃ alone.

When the exposure period was extended to 2 to 7 days (long-term exposure), the increase in the content of the total amino acids was observed in most of treatments. Roots of the plants exposed to various concentrations of NO₂ and O₃ showed the most remarkable increase in the content of total amino acids. Asparagine, in place of glutamine, became a major amino acid. The percentage of asparagine was especially increased by the mixed exposure to NO₂ and O₃ These results indicate that glutamine which accumulates considerably in the early phase of the gas exposure (short-term exposure) seems to be gradually converted into other amino acids, mainly asparagine.

The correlation between the content of each amino acid, ammonium and total amino acids was calculated using data from the above experiment. Most of the amino acids in the primary and trifoliate leaves showed a high correlation with the total amino acids, suggesting that the changes in the amount of total amino acids caused by the air pollutants may be reflected not only by a particular amino acid, but also by an individual amino acid composing soluble metabolite pool. A high correlation was obtained among amino acids belonging to the serine family such as glYCine, serine, and cysteine.     

Evaluation of four different crops’ sensitivity to sulfosulfuron and tribenuron methyl soil residues

ABSTRACT

On the basis of greenhouse bioassays, the sensitivities of root and shoot biomass of barley (Hordeum vulgare L.), corn (Zea mays L.), oilseed rape (Brassica napus L.) and sugar beet (Beta vulgaris L.) to soil-incorporated sulfosulfuron and tribenuron methyl were assessed. Shoot and root biomass production was measured 30 days after emergence. Plant responses, including roots and shoots dry weight per pot, were described by a three parameter log-logistic regression model as a function of sulfosulfuron or tribenuron methyl doses and the relative sensitivities were calculated at the various ED-levels with their associated 95% confidence intervals. The most precise ED-levels were that at ED₅₀ and sensitivity rank was oilseed rape, sugar beet, corn and barley, whatever the chosen response level and herbicide. We calculated relative sensitivities at ED₁₀, ED₅₀ and ED₉₀ for the species of barley, the most tolerant crop, as reference. Comparison of relative sensitivity of crops to both herbicides showed that the sensitivity of these crops was much larger for tribenuron methyl than for sulfosulfuron. Oilseed rape was the most sensitive species (ED₅₀?=?0.202 and 0.179?µg?kg^?1 soil for root dry weight (RDW) response to sulfosulfuron and tribenuron methyl, respectively) while barley was the most tolerant one (ED₅₀?=?1.008 and 3.68?µg?kg^?1soil for RDW response to sulfosulfuron and tribenuron methyl, respectively). Sugar beet and corn had intermediate sensitivity. Also, we demonstrated how important it is to show the confidence intervals of relative sensitivities. In several instances the relative sensitivities, even numerically large, were not significantly different from 1.00. We demonstrate that classifying biotypes as resistant to a herbicide requires the threshold of resistance/susceptible (R/S) of 4.00 only be accepted if confidence intervals do not cover 1.00.     

Yield response of corn to lime and urea application on an acidic tropical soil

Abstract

The effects of liming (7 500 kg CaCO₃/ha) and rate of urea application (0,50,100, and 200 kg N/ha) and its placement at the surface or at 5 cm depth on grain yield and nutrient uptake by corn grown on an acidic tropical soil (Fluventic Eutropept) were studied. Liming significantly increased grain yield, N uptake, and P and K uptake although Ca and Mg uptake, generally, were unaffected. Sub‐surface application of urea increased N uptake only. Yield response to applied N was observed up to 50 kg N/ha when limed but at all rates in the absence of liming. It therefore, reduced the fertilizer N requirement for optimum grain yield. Liming the acidic soil also reduced exchangeable Al but increased nitrification rate and available P in the soil profile (at least up to 0.6 m depth).     

The effect of soil lead sorption capacity on the uptake of lead by corn

Abstract

Lead uptake by four‐week‐old corn shoots grown in Fb‐amended soils was found to be dependent upon the level of Pb in the soil relative to the soil's capacity to sorb Pb. At a given level of added Pb, lead uptake by plants was found to decrease with an increase in soil pH, cation exchange capacity, and available phosphorus.     

C and N dynamics of a range of biogas slurries as a function of application rate and soil texture: a laboratory experiment

Digestates vary in composition and studies regarding their impact on C and N dynamics in soils are scarce. The objective was to analyse the C and N dynamics of digestates originating from various substrates applied to a sandy Cambisol and a silty Anthrosol. In three laboratory experiments (4–6 weeks), the effects of digestate properties, N rate and water content were tested. Averaged over both soils, 21% of the C supplied was emitted as CO₂. Potential NH₃ emissions during the first week ranged between 6% and 12% of NH₄⁺ present in the digestates. The emission factors in the sandy Cambisol were on average 1.2 and 2 times higher for CO₂ and potential NH₃, respectively, compared to the silty Anthrosol. Similarly, net nitrogen mineralization in the sandy Cambisol was approximately twice the N mineralized in the silty Anthrosol. Net nitrification was not influenced by soil texture or different digestates, but increased with increasing application rates and had highest values at 75% of water holding capacity. Our results indicate that the type of substrate input for anaerobic digestion influences the properties of the digestate and therefore the dynamics of C and N. However, soil texture can affect these dynamics markedly.     

Rehabilitation of saline soil with biogas digestate,humic acid,calcium humate and their amalgamations

ABSTRACT

Amelioration of saline soil is a requisite in order to increase crop productivity. A soil incubation study was performed for 60 days using digestate, humic acid, calcium humate and their combinations to investigate the influence on physical, chemical, microbial and enzyme activities of saline soil. Overall, digestate combined with calcium humate followed by humic acid treatments have shown their potency in decreasing the soil pH, electrical conductivity (EC), and sodium ion (Na⁺) concentration, and increase in potassium ion (K ⁺), calcium ion (Ca ²⁺), magnesium ion (Mg ²⁺), mean weight diameter (MWD), soil enzyme activities, microbial biomass carbon (MBC), MBC: microbial biomass nitrogen (MBN) and soil respiration than control. The digestate, humic acid individually and their amalgamation evidenced greater MBN among all the treatments. The digestate alone efficiently improved the soil properties than humic acid and calcium humate individual groups except for the MWD where it is pronounced more in the latter groups. The greater metabolic quotient (qCO₂) was observed in control than organic matter amended treatments indicating the stress conditions. The increase in water-extractable organic matter (WEOM) with minimal aromaticity (specific ultraviolet absorbance at 254 nm-Suva ₂₅₄) in integrated amendments comprising groups, laid the ground reason to improve the properties of saline soil. Therefore, this study concludes that the fusion of fresh and humified substrates could facilitate reclamation.     

Chemical fixation of ammonia to soil organic matter after application of urea

Chemical fixation of NH₃ to soil organic matter was studied in two Swedish soils with different contents of organic matter: a clay soil with 2.3% C and an organic soil with 36.6% C. ¹⁵N‐labelled urea was applied at different rates to both sterilized and non‐sterilized soils. After 10 days, the soils were extracted and washed with K₂SO₄ and determined for total N and atom% ¹⁵N excess. Urea N was recovered as non‐extractable N in sterilized soil corresponding to 9.7% of supplied ^l5N‐labelled urea in the organic soil and 2.2% in the clay soil. Since no biological immobilization is thought to occur in the sterile soil, this non‐extractable N is suggested to be chemically fixed to soil organic matter. Owing to urea hydrolysis in the clay soil, pH increased from 6.3 to 9.3 and in the organic soil from 5.7 to 6.9 and 8.8, respectively, at the low and high urea supply.     

土壤有机矿质复合体研究Ⅵ.胶散复合体的化学组成及其结合特征

本文研究水热条件渐变的地带性土壤中Ｇ１、Ｇ２组胶散复合体有机、无机物的化学组成及其结合特点。结果表明：Ｇ２组中铁有积累现象，游离态铁、铝氧化物含量为Ｇ２＞Ｇ１，但均随土壤类型变化。松结态腐殖质（Ｈ１）为Ｇ１＞Ｇ２，紧结态腐殖质（Ｈ３）则为Ｇ１＜Ｇ２。可提取腐殖质中，松、稳结态腐殖质之比值Ｈ１／Ｈ２和胡敏酸、富里酸之比值ＨＡ／ＦＡ，除个别土壤之外，都相关不大。Ｇ１、Ｇ２两组复合体中都含有一定数量的络     

Relationship of soil properties to pyroxasulfone bioactivity in a range of prairie soils

The relationship between pyroxasulfone bioactivity and soil properties has not been investigated in a wide range of soils typical of western Canada. In this study, 47 soils from Saskatchewan, Manitoba and Alberta, with varying organic matter content (1.5%–22.1%), pH (5.0–7.9), and clay content (6.8%–59.4%) were used to evaluate the effect of soil properties on pyroxasulfone bioactivity and its relevance to field application rates. Bioactivity was assessed by measuring the reduction of sugar beet shoot length after 7 days in response to 0, 92, 184, and 368 µg?ai?kg^?1 pyroxasulfone concentration in soil. Multiple regression analysis showed that pyroxasulfone bioactivity was related to soil organic matter content, pH and clay content. Grouping the soils according to these properties allowed for a summarization of pyroxasulfone field application rates required to achieve bioactivity based on the magnitude of sugar beet shoot length inhibition (%). The estimated field application rates ranged from less than 120–480 g?ai?ha^?1.     

区分土壤中硝化与反硝化对N2O产生贡献的方法

土壤是产生N₂O的最主要来源之一。硝化和反硝化反应是产生N₂O的主要机理，由于硝化和反硝化微生物同时存在于土壤中，因而硝化和反硝化作用能同时产生N₂O。N₂O的来源可通过使用选择性抑制剂，杀菌剂以及加入的标记底物确定。通过对生成N₂O反应的每一步分析，主要从抑制反应发生的催化酶和细菌着手，总结了测量区分硝化、反硝化和DNRA反应对N₂O产生的贡献方法。并对¹⁵N标记底物法，乙炔抑制法和环境因子抑制法作了详细介绍。     

Cassava (Manihot Esculenta Crantz) Yields,Soil Nitrous Oxide Emission,and Soil Nitrogen Transformation Affected by Nitrification Inhibitors in Loamy Sand Soil in Thailand

The effects of nitrification inhibitors (NIs) on soil nitrous oxide (N₂O) emission, soil ammonium (NH₄⁺) and nitrate (NO₃^?), and cassava (Manihot esculenta Crantz) yields were investigated in a loamy sand soil in eastern Thailand. Treatments were chemical fertilizer (CF) and CF plus dicyandiamide (DCD) or neem (Azadirachta indica) oil at two rates of 5% and 10%. DCD had a greater reduction of soil N₂O flux than the neem oil (P<0.10). DCD and neem oil retained NH₄⁺-N in the soil by 79% and 63% (P ≤ 0.10), respectively. The NI effect on soil NO₃^?-N was small due to a low N fertilizer rate. The cassava root yield and N uptake were increased 4–11% and 2–18%, respectively, by use of NIs, but they were only significant for DCD (P ≤ 0.10). These findings suggest that NIs application may be a promising method for minimizing nitrogen loss and enhancing crop yields in a tropical cassava field.     

Winter soil CO2 efflux and its contribution to annual soil respiration in different ecosystems of a forest-steppe ecotone, north China

Most soil respiration measurements are conducted during the growing season. In tundra and boreal forest ecosystems, cumulative winter soil CO₂ fluxes are reported to be a significant component of their annual carbon budgets. However, little information on winter soil CO₂ efflux is known from mid-latitude ecosystems. Therefore, comparing measurements of soil respiration taken annually versus during the growing season will improve the accuracy of ecosystem carbon budgets and the response of soil CO₂ efflux to climate changes. In this study we measured winter soil CO₂ efflux and its contribution to annual soil respiration for seven ecosystems (three forests: Pinus sylvestris var. mongolica plantation, Larix principis-rupprechtii plantation and Betula platyphylla forest; two shrubs: Rosa bella and Malus baccata; and two meadow grasslands) in a forest-steppe ecotone, north China. Overall mean winter and growing season soil CO₂ effluxes were 0.15-0.26 μmol m⁻² s⁻¹ and 2.65-4.61 μmol m⁻² s⁻¹, respectively, with significant differences in the growing season among the different ecosystems. Annual Q₁₀ (increased soil respiration rate per 10 °C increase in temperature) was generally higher than the growing season Q₁₀. Soil water content accounted for 84% of the variations in growing season Q₁₀ and soil temperature range explained 88% of the variation in annual Q₁₀. Soil organic carbon density to 30 cm depth was a good surrogate for SR₁₀ (basal soil respiration at a reference temperature of 10 °C). Annual soil CO₂ efflux ranged from 394.76 g C m⁻² to 973.18 g C m⁻² using observed ecosystem-specific response equations between soil respiration and soil temperature. Estimates ranged from 424.90 g C m⁻² to 784.73 g C m⁻² by interpolating measured soil respiration between sampling dates for every day of the year and then computing the sum to obtain the annual value. The contributions of winter soil CO₂ efflux to annual soil respiration were 3.48-7.30% and 4.92-7.83% using interpolated and modeled methods, respectively. Our results indicate that in mid-latitude ecosystems, soil CO₂ efflux continues throughout the winter and winter soil respiration is an important component of annual CO₂ efflux.     

AMELIORATIVE EFFECTS OF DI-POTASSIUM HYDROGEN ORTHOPHOSPHATE ON SALT-STRESSED EGGPLANT

To overcome salinity stress, a factorial experiment block design (4 × 7) was done on eggplant cv. ‘Topaz F₁’ to investigate the effects of foliar sprays of di-potassium hydrogen orthophosphate (K₂HPO₄; 0 and 10 mM) on growth, yield and chemical composition under sodium chloride (NaCl; 0 and 50 mM) stress. Sodium chloride treatment produced less vegetative growth, dry matter, total sugar content and fruit yield as compared with those in control. However, free phenols increased in fruit by salinity treatment. Spraying K₂HPO₄ ameliorated the negative effects of salinity on plant growth, fruit yield, and fruit total sugar content. Sodium content increased by salinity and the sodium uptake did not reduce by application of K₂HPO₄. While spraying of K₂HPO₄ lowered the sodium accumulation in fruit. Potassium and calcium content in all plant parts and phosphorus, in shoot only were in the deficient ranges in plants treated with NaCl and these deficiencies were corrected by foliar application of K₂HPO4.     

Characteristics of greenhouse gas emissions from rice paddy fields in South Korea under climate change scenario RCP-8.5 using the DNDC model

Understanding the greenhouse gas(GHG)emission from rice paddy fields is essential to come up with appropriate countermeasure in response to global warming.However,GHG emissions from paddy fields in South Korea are not well characterized.The objectives of this study were to estimate the carbon dioxide(CO₂)and methane(CH₄)emissions from rice paddy fields in South Korea,under the Representative Concentration Pathway 8.5(RCP-8.5)climate change scenario using the DNDC(i.e.,DeNitrification-DeComposition)model at 1-km²resolution.The performance of the model was verified with field data collected using a closed chamber,which supports the application of the model to South Korea.Both the model predictions and field measurements showed that most(>95%)GHG emissions occur in the cropping period,between April and October.As a baseline(assuming no climate change),the national sums of the CO₂and CH₄emissions for the 2020 s and 2090 s were estimated to be 5.8×10⁶and 6.0×10⁶t CO₂-equivalents(CO₂-eq)year^-1for CO₂and 6.4×10⁶and 6.6×10⁶t CO₂-eq year^-1for CH₄,respectively,indicating no significant changes over 80 years.Under RCP-8.5,in the 2090 s,CH₄emissions were predicted to increase by 10.7×10⁶and 14.9×10⁶t CO₂-eq year^-1,for a 10-or 30-cm tillage depth,respectively.However,the CO₂emissions gradually decreased with rising temperatures,due to reduced root respiration.Deep tillage increased the emissions of both GHGs,with a more pronounced effect for CH₄than CO₂.Intermittent drainage in the middle of the cropping season can attenuate the CH₄emissions from paddy fields.The findings of this work will aid in developing nationwide policies on agricultural land management in the face of climate change.     

Nitrification Inhibitor Effects on Nitrous Oxide Emission,Nitrogen Transformation,and Maize (Zea mays L.) Yield in Loamy Sand Soil in Thailand

The nitrification inhibitors (NIs) effects on soil nitrogen (N) fates and maize yields were investigated in a loamy-sand soil in Thailand. The treatments were chemical fertilizer (CF) and CF with dicyandiamide (DCD) or neem oil at two rates of 5% and 10%. Compared to the CF plot, DCD and neem oil reduced the cumulative nitrous oxide (N₂O) emission by the equivalent of 26% and 10%, respectively (P < 0.05). DCD and neem oil had a positive effect in slowing ammonium (NH₄⁺)-conversion and prolonging NH₄⁺-N in the soil with a maximum efficiency of 45% and 30%, respectively. NO₃^–N was higher in the NI plots (P < 0.05), but the effect was less pronounced later in the growing season. Adding the NIs increased maize yields and N uptake, but was only significant (P < 0.10) for neem oil. Results indicate that applying NIs is an effective method to mitigate soil N losses and enhancing N use efficiency in a tropical, agricultural field.     

GREENHOUSE GAS EMISSIONS FROM AN ALKALINE SALINE SOIL CULTIVATED WITH MAIZE (ZEA MAYS L.) AND AMENDED WITH ANAEROBICALLY DIGESTED COW MANURE: A GREENHOUSE EXPERIMENT

Sludge derived from cow manure anaerobically digested to produce biogas (methane; CH₄) was applied to maize (Zea mays L.) cultivated in a nutrient-low, alkaline, saline soil with electrolytic conductivity 9.4 dS m^?1 and pH 9.3. Carbon dioxide (CO₂) emission increased 3.1 times when sludge was applied to soil, 1.6 times when cultivated with maize and 3.5 times in sludge-amended maize cultivated soil compared to the unamended uncultivated soil (1.51 mg C kg^?1 soil day^?1). Nitrous oxide (N₂O) emission from unamended soil was -0.0004 μg nitrogen (N) kg^?1 soil day^?1 and similar from soil cultivated with maize (0.27 μg N kg^?1 soil day^?1). Application of sludge increased the N₂O emission to 4.59 μg N kg^?1 soil day^?1, but cultivating this soil reduced it to 2.42 μg N kg^?1 soil day^?1. It was found that application of anaerobic digested cow manure stimulated maize development in an alkaline saline soil and increased emissions of CO₂ and N₂O.     

Soil Properties Influence Distribution of Extractable Boron in Soil Profile

Depth distribution of boron (B) extractable by hot calcium chloride (HCC), potassium dihydrogen phosphate (PDP), and tartaric acid (TA) in some typical B‐deficient Inceptisols, Entisols, and Alfisols in relation to soil properties was studied. The magnitude of B extraction followed the order HCC > PDP > TA for Inceptisols, TA > HCC > PDP for Entisols, and PDP > HCC > TA for Alfisols and showed a decrease along soil depth. The low pH of TA and effective desorption of B by phosphate of PDP are attributed to their higher efficiency in extracting B in Entisols and Alfisols, respectively. A decrease in organic carbon (C), clay, and amorphous iron oxide content was responsible for the observed decrease in extractable B along depth of soil profile. The HCC showed more efficiency than PDP and TA for extracting B in soils high in organic C. Multiple regression equations explained only 21, 57, and 59% of the variability in PDP‐, HCC‐, and TA‐extractable B content in soils by the soil properties analyzed, of which organic C and clay were the most important. There were dynamic equilibria among the amount of B extracted by the extractants, indicating B extraction by them from more or less similar pools in the soils.