Soil Respiration and Carbon Storage of an Acrisol Under Forest and different Cultivations in rio de Janeiro State, Brazil

Soil respiration rates of a clay-loam textured Acrisol under different uses (Atlantic forest, manioc, horticulture and pasture) from Rio de Janeiro State were measured. The relationship between carbon dioxide (CO₂) emissions and soil physico-chemical properties were investigated. Rates of CO₂ emission of two sites (Atlantic forest and horticulture) were also evaluated in different seasons in 1997 and 1998. In the forest site, monthly means of measured respiration rates showed good correlation with soil temperature in the range 19.6–24.1°C (r² = 0.89). In the horticulture site, no change was observed with soil moisture alone, in the range 3.0–13.2 wt%. In the horticulture soil, even when the surface soil was very dry, respiration rates increased in the hot, wetter summer but remained higher than the mean flux from forest soil. The CO₂ emission flux of the Acrisol under different use showed good correlation with soil temperature (r² = 0.72) and moisture (r² = 0.61).     

Soil respiration of forest ecosystems in gradients of environmental pollution by emissions from copper smelters

The effect of industrial pollution on soil respiration measured in situ has been studied along two gradients formed by emissions from large copper smelters: the Middle Ural Copper Smelter (spruce-fir forests) and Karabash Copper Smelter (birch forests). Pollution has proved to have a slight effect on soil respiration: its rate drops only in the zone of industrial barren. There is no correlation between soil respiration and distance to the emission source, metal contents in the litter, or litter acidity. A hypothesis is proposed that this may be due to a shift in the ratio of the root and microbial components of respiration in the pollution gradient.     

川西亚高山云杉叶凋落物质量损失过程及土壤生物的作用

采用分解袋法,研究了川西亚高山云杉纯林与混交林叶凋落物的质量损失过程及土壤动物与微生物的作用。结果如下:(1)云杉叶凋落物分解过程中,土壤动物数量总体呈下降趋势,即土壤动物主要在分解前期发挥作用,其中,大型土壤动物早期以植食性的蛴螬为主,中期以捕食性的石蜈蚣为主,后期以腐食性的马陆为主;中小型土壤动物始终以螨类、跳虫和线虫为优势类群;相关分析表明线虫数量与云杉叶凋落物分解速率相关性最大,大型土壤动物次之。(2)云杉叶凋落物分解过程中,微生物数量总体呈上升趋势,即土壤微生物主要在分解后期发挥作用,进一步相关分析表明真菌数量与云杉叶凋落物分解速率相关性大于细菌和放线菌。(3)云杉纯林叶凋落物分解速率低于混交林,其中分解3、15、21、24个月时,纯林小孔径分解袋失重率分别为混交林的65.51%、95.73%、98.91%、94.8%,大孔径分解袋失重率分别为混交林的89.83%、92.95%、98.13%、97.13%,即,两类林分小孔径分解袋及凋落物分解前期失重率差异更为明显,表明凋落物分解速率既受底物质量的影响,也和参与分解的土壤生物有关,其中与线虫、大型土壤动物及真菌的数量相关性最大。     

Evaluation of 14C abundance in soil respiration using acclerator mass spectrometry

To clarify the behavior of 14C in terrestrial ecosystems, 14C abundance in soil respiration was evaluated in an urban forest with a new method involving a closed chamber technique and 14C measurement by accelerator mass spectrometry (AMS). Soil respiration had a higher Delta14C than the contemporary atmosphere. This indicates that a significant portion of soil respiration is derived from the decomposition of soil organic matter enriched in 14C by atmospheric nuclear weapons tests, with a notable time lag between atmospheric 14C addition and re-emission from soil. On the other hand, delta14C in soil respiration demonstrated that 14C abundance ratio itself in soil-respired CO2 is not always high compared with that in atmospheric CO2 because of the isotope fractionation during plant photosynthesis and microbial decomposition of soil organic matter. The Delta14C in soil respiration was slightly lower in August than in March, suggesting a relatively high contribution of plant root respiration and decomposition of newly accumulated and/or 14C-depleted soil organic matter to the total soil respiration in August.     

Farmers perception and awareness of climate change: a case study from Kanchandzonga Biosphere Reserve,India

This study was an attempt to document the indigenous Lepcha people’s perception on climate change-related issues in five villages of Dzongu Valley located in Kanchandzonga Biosphere Reserve, India. Personal structured questionnaire was used for interview of 300 households selected randomly. Results showed that 85 % of the households have perceived climate change, mainly in the form of increasing temperature and unpredictable pattern of rainfall. In terms of climate change-related events, 75 % of the households believed that wind is becoming warmer and stronger over the past years. Majority of the households have observed changes in crop phenology, while about 90 % agreed that the incidences of insect pest and diseases have increased over the years, especially in their large cardamom crop. A comparison of community perceptions, climatic observations and scientific literature shows that the community have correctly perceived temperature change, unpredictable occurrence of rainfall and increased incidence of insect pest and diseases, which have largely influenced the experiences and perceptions regarding climate-related events. Results reveal that households have adopted the use of locally available material as mulches against soil erosion, to conserve the soil moisture and manage soil temperature. Majority of the households have diversified their cropping system through traditional agroforestry systems and intercropping. Unfortunately, most of the households were unaware about the scientific sustainable approaches to combating impact of climate change. This documentation will aid in assessing the needs in terms of actions and information for facilitating climate change-related adaptation locally in Sikkim state of India.     

Analysis of the soil water balance for large-scale reforestation with <Emphasis Type="Italic">Eucommia ulmoides</Emphasis> in the hilly red soil region of southern China

Returning farmland to forests is important for the protection of ecological values. Eucommia ulmoides is considered to be a suitable species for reforestation in the hilly red soil region of southern China. The objective of this study was to investigate the relationship between the water supply and demand of an E. ulmoides plantation to provide insights into the feasibility of large-scale planting for ecological restoration and forest management activities in the hilly red soil region of southern China. With the measured precipitation, surface runoff and interflow and actual evapotranspiration (ET_c) estimated by the modified P–M model, soil water storage (SWS) was estimated based on the water balance equation. Monthly variations of SWS were then compared with in situ measured SWS. The results showed that the estimated mean monthly water losses (the sum of the surface runoff, interflow and ET_c) were 139.8 mm in a wet year and 120.0 mm in a dry year, while the measured mean monthly water input values (net precipitation) were 131.2 mm in a wet year and 70.8 mm in a dry year. Net soil water storage (ΔSWS) was negative in each month of the growing season in a dry year, but the soil water deficit was replenished during the following season. The model performance showed that the modified P–M model can be adapted to estimate the soil water storage in other forest catchments where no adequate in situ data are available. As a result of estimating the water balance and observing soil water storage in two different hydrological years, E. ulmoides is recommended as a suitable forest rehabilitation species in the study area, and a suitable plant region has been defined by the GIS technique based on the water balance model.     

Combining remote sensing and household level data for regional scale analysis of land cover change in the Brazilian Amazon

Land cover change in the Brazilian Amazon depends on the spatial variability of political, socioeconomic and biophysical factors, as well as on the land use history and its actors. A regional scale analysis was made in Rondônia State to identify possible differences in land cover change connected to spatial policies of land occupation, size and year of establishment of properties, accessibility measures and soil fertility. The analysis was made based on remote sensing data and household level data gathered with a questionnaire. Both types of analyses indicate that the highest level of total deforestation is found inside agrarian projects, especially in those established more than 20 years ago. Even though deforestation rates are similar inside and outside official settlements, inside agrarian projects forest depletion can exceed 50% at the property level within 10–14 years after establishment. The data indicate that both small-scale and medium to large-scale farmers contribute to deforestation processes in Rondônia State encouraged by spatial policies of land occupation, which provide better accessibility to forest fringes where soil fertility and forest resources are important determinants of location choice.     

Spatio-temporal analysis of climatic variables in the western part of Bangladesh

Monitoring and detecting trends of climatic variables like rainfall and temperature are essential for agricultural developments in the context of climate change. The present study has detected trends in annual and cropping seasonal rainfall and temperature data for the period of 1961–2011 using Mann–Kendall (MK) test, Spearman’s rho (SR) test and modified Mann–Kendall test that has been applied to the significant lag-1 serial correlated time series data, and slope has been estimated using Sen’s Slope estimator for twelve meteorological stations located in the western part of Bangladesh covering about 41 % of the country. Almost 71 % trends explored by MK test in annual rainfall are statistically insignificant, and SR test also complies it. The spatial distribution of rainfall trend shows insignificant positive trends in major part of the area. Significant positive trends both by MK test and by SR test at 95 % confidence levels are observed at rates of 8.56, 11.15 and 13.66 mm/year at Dinajpur, Rangpur and Khepupara stations, respectively, and the Kharif season rainfall of these stations also shows significant increasing trends except Dinajpur. On the other hand, significant decreasing trends in annual rainfall are found at Bhola (?11.67 mm/year) and Rajshahi (?5.951 mm/year) stations and decreasing trends in rainfall dominated the Pre-Kharif season over the area. But, 83.33 % of the stations show rising trends in annual mean temperature with significant positive trends (as observed by both MK test and SR test) at Rangpur, Bogra, Faridpur, Jessore and Bhola stations where the rate of changes vary from 0.013 °C/year at Faridpur to 0.08 °C/year at Bhola. Most of the trends in Rabi and Pre-Kharif seasons of mean temperatures are not statistically significant. However, all stations except Barisal show significant rising trends in temperature in Kharif season. To cope with this changing pattern of rainfall and temperature, effective adaptation strategies should be taken to keep up the agricultural production that is related to livelihood of the most people and to ensure the country’s food security.     

Spatial pattern of recent rainfall trends in Serbia (1961–2009)

This paper examines a spatial pattern of annual, seasonal and monthly rainfall trends in Serbia. The study used data from 63 weather stations between the period of 1961–2009. The rainfall series was examined by applying the nonparametric method of the Mann–Kendall test and Sen’s method to determine the significance and magnitude of the trends. Significant trends have not been detected for the whole country at an annual scale. Seasonal trends at the confidence level of 97.5 %, however, indicate a slight decrease in winter (5 stations out of 63) and spring (7 stations out of 63) precipitation and an increase in autumn precipitation (10 stations out of 63). Results for monthly rainfall trends also generally showed a nonsignificant trend with the exception of a negative trend in May (6 stations out of 63) and positive trend for October (9 stations out of 63). Calculated global autocorrelation statistics (Moran’s I) indicate a random spatial pattern of rainfall trends on annual, seasonal and monthly timescales with exceptions for March, June and November. Overall, results suggest that only weak, mostly nonsignificant trends are present in Serbia in the period 1961–2009.     

Microbial population dynamics under fertigation by distillery effluent in sugarcane-ratoon cropping system

Distillery effluents, a major by-product of distilleries are a major environmental hazard as they are rich in organic matter, micro- and macroelements. Management of this enormous amount of nutrient-rich effluent and its effective utilization is a major challenge. These effluents can be used as a source of nutrient by C₄ crops like sugarcane and subsequent ratoon crops under fertigation system. Impact of fertigation in sugarcane-ratoon cropping system on soil microbial biomass is important as the microbial population plays an important role in the nutrient and biogeochemical recycling. Keeping this in mind, a field experiment was carried out in the sandy loam soil of semi-arid to humid sub-tropical climate of Gajraula (28.85°N, 78.23°E) region, India with different doses of diluted and undiluted effluent for fertigation of sugarcane crop in presence and absence of 50 % recommended dose of fertilizers with suitable replicates. Two post-sown irrigations with four times diluted effluent gave the maximum yield in case of sugarcane crop. Taking into consideration the yield and the culturable microbial population sizes, it can be concluded that one to two post-sown irrigations with diluted effluent can be used to enhance soil fertility in terms of microbial population and to enhance sugarcane and ratoon crop productivity. This package is economically viable and can also take care of distillery waste management and reduction in consumption of chemical fertilizers by 50 %, a key for sustainable agricultural development.     

长江上游高山森林林窗对凋落物分解过程中可溶性碳的影响

采用凋落物分解袋法, 以川西高山森林典型乔木(四川红杉Larix mastersiana、岷江冷杉Abies faxoniana、红桦Betula albo-sinensis和方枝柏Sabina saltuaria)和灌木(高山杜鹃Rhododendron lapponicum和康定柳Salix paraplesia)凋落物为研究对象, 研究了林窗中心到郁闭林下不同生境(林窗中心、林冠林窗、扩展林窗和郁闭林下)中凋落物第一年分解不同关键时期(雪被形成期、雪被覆盖期、雪被融化期和生长季节)可溶性碳的动态特征。结果表明:6种凋落物可溶性碳和可溶性有机碳在冬季含量增加而在生长季节含量降低, 而可溶性无机碳含量在全年呈降低趋势;雪被形成期, 6种凋落物可溶性碳和可溶性有机碳在郁闭林下达到最大值, 而雪被覆盖期在林窗中心和林冠林窗达到最大值, 生长季节6种凋落物可溶性碳含量均低于初始含量。这表明全球气候变暖情景下, 冬季林内雪被覆盖时间和厚度降低且生长季节延长将减少凋落物可溶性碳含量, 且变化程度受到凋落物质量控制。     

Carbon Emission by Soils in Forests Damaged by the Siberian Moth

In the southern-taiga low grass–green moss fir forest completely defoliated by the Siberian moth, the rate of soil respiration in the third year after the pest population outbreak was 1.5 times higher than in an undisturbed tree stand. This was explained by a significant increase in the abundance and activity of soil microorganisms in the pest-defoliated forest, which occurred due to the qualitative changes in the litter composition and the increased temperature and moisture in the upper soil layers. The rate of carbon emission from the soil in the defoliated forest was 41.7 kg/ha per day, compared to 28.3 kg/ha per day in the undisturbed fir forest.     

The influence of soil pollution on soil microbial biomass and nematode community structure in Navoiy Industrial Park, Uzbekistan

The effects of ammonium-rich and heavy-metal air pollution produced by the industrial enterprises at Navoiy (Uzbekistan) on soil free-living nematodes and microbial population activities was investigated in soil samples collected in a 5-km radius surrounding the industrial enterprises. At each location (n=4), soil samples were collected from the upper layer (0-10 cm) for determination of soil moisture (SM), total organic carbon (C(org)), total soluble nitrogen (TSN), soil electrical conductivity (EC) and cations (Ca(2+), K(+), Na(+)). Heavy metals (As, Cu, Pb, Zn), soil basal respiration (BR), microbial biomass (C(mic)) and nematode populations were determined. The highest level of TSN was found near the industrial enterprises, with 23.8 and 24.0 mg/kg at NavoiAzot and NavoiGRES, respectively. Soil sample pH was found to be weakly alkaline, with levels ranging between 7.9 and 8.1. Mean soil moisture content varied from 0.75% to 0.93% of the wet weight, without any significant differences between the sampling stations. The heavy metals As, Cu, Pb and Zn were accumulated in the upper soil layer. A significant difference was found between soil heavy-metal content for Cu (p<0.0005) and As (p<0.02). Basal respiration and microbial coefficient (C(mic)/C(org)) were found to be significantly negatively correlated with Cu and As soil content. A significantly positive correlation was found between the Cd concentration and the metabolic quotient (qCO(2)) (p<0.003). No significant correlation was observed between the soil microbial population and total soluble nitrogen. Furthermore, the qCO(2), which is a known ecophysiological index for the soil microbial population, was found to be correlated with the total number of nematodes in general and with the bacteriovore-feeding group in particular. No significant correlation was observed between the soil microbial population and total soluble nitrogen.     

Ecophysiological indicators of microbial biomass status in chernozem soils of the Central Caucasus (in the territory of Kabardino-Balkaria with the Terek variant of altitudinal zonation)

A comparative assessment of the biological properties of chernozem soils in agro- and biogeocenoses has been made by determining the rates of basal and substrate-induced soil respiration and using these data to calculate ecophysiological indices characterizing the potential and stability of soil microbial biomass. The results show that the rate of CO₂ emission and the contents of microbial biomass carbon in agriculturally exploited chernozem soils have decreased by factors of 3 and 2.6, respectively. The values of microbial metabolic quotients are indicative of medium-to-strong disturbance to the stability of microbial communities in chernozem soils of agrocenoses.     

Effect of arsenic contamination on microbial biomass and its activities in arsenic contaminated soils of Gangetic West Bengal, India

A study was conducted to see the effect of arsenic contamination on soil quality indicators, viz., microbial biomass, soil respiration, fluorescein diacetate and dehydrogenase (DHG) activity in arsenic contaminated soils of West Bengal. All the parameters were significantly and negatively correlated with all the form of arsenic (bioavailable and total) but the microbial metabolic quotient was significantly and positively correlated with all forms of arsenic, indicating arsenic induced stress to the soil microbial community. This may be due to part of the microbial biomass, which is located in the inner parts of the micro-aggregates of soil, which is affected by arsenic accumulates present in soil particles. Linear regression analysis revealed that the bioavailable arsenic exerted greater inhibitory effect on the soil microbial population than the total arsenic content of soils. Water-soluble arsenic showed more inhibitory effect than NaHCO(3) extractable form, in their association with biological properties of the contaminated soils. Water-soluble form of arsenic was much more toxic than insoluble forms. This signified that with increase in bioavailability, the arsenic exerted more inhibitory effect on these parameters. It is thus suggested that the microbial biomass, fluorescein diacetate and dehydrogenase activity alone and expressed on a soil organic matter basis along with the soil respiration parameters can be helpful in assessing the effects of arsenic on the size and activity of microbial biomass in soils.     

Beryllium-7 in near-surface air and deposition at Brisbane, Australia

Measurements of 7Be concentrations in near-surface air and 7Be deposition were carried out at Brisbane, Australia. Concentrations of 7Be in near-surface air measured over 4 years show seasonal variations with values above the annual mean occurring mainly in the spring and summer months of each year. These higher concentrations coincide with the expected influx of stratospheric air to the planetary boundary layer in early spring and higher rates of convective circulation within the troposphere during summer. 7Be deposition measurements over 3 years show seasonal variations similar to the seasonal rainfall pattern. There is a statistically significant (p<0.001) linear relationship between monthly (7)Be deposition and rainfall amount. This relationship is used to calculate the net cumulative (7)Be areal activity density.     

Monitoring microbial biomass and respiration in different soils from the Czech Republic--a summary of results

The microbial biomass (Cbio), respiration (basal respiration (BR) and potential respiration (PR)), and derived indices for 520 independent soil samples of 117 different soils from the Czech Republic were statistically analysed. The broad range of soil samples allowed the stepwise breakdown of the database into six reasonable categories of soil: arable soils, loamy grassland soils, sandy grassland soils with weak organic matter content, sandy grassland soils with moderate organic matter content, forest soils with moderate organic matter content, and forest organic soils with rich organic matter content. Because soil microbiology lacks benchmarking values, the ranges of the microbial characteristics for these categories were stated and are presented here. The separation into soil groups narrowed the ranges enough to be useful for comparative purposes. The groups displayed significant differences in basal microbial parameters. The lowest microbial biomass was found in arable soils and grassland sandy soils with weak organic matter content. The highest microbial biomass was shown by loamy grassland soils and organic forest soils. Respiration displayed similar results to the microbial biomass. The derived indices revealed less significant differences confirming their inner-standard nature. The relationships between the soil contamination and microbial parameters were not explored because of the confounding effect of soil organic matter. However, it was not shown by the category of grassland sandy soils with weak organic matter content suggesting they could be especially suitable for the biomonitoring of harmful effects of chemicals on soil microorganisms.     

向家坝水电站不同修复模式下根际土壤微生物化学计量特征

为探究水电站扰动区人工植被恢复后土壤质量及肥力的变化，以向家坝植被混凝土、厚层基材和框格梁3种典型边坡下优势物种荩草根际与非根际土壤为研究对象，对土壤的养分和微生物生态化学计量比进行研究。结果表明：（1）植被混凝土、厚层基材样地的养分平均含量均显著高于框格梁样地；植被混凝土、框格梁样地下土壤养分含量在根际存在一定的富集，以有机碳的富集作用最为明显，而厚层基材样地则表现为土壤全量养分在根际土壤中存在亏缺;（2）植被混凝土和框格梁修复模式样地的土壤微生物量为根际土壤较高，MBC/MBN、MBC/MBP表现为非根际土壤较高，3种样地下根际与非根际土壤微生物生态化学计量比差异性显著（P＜0.05）;（3）相关性分析表明，土壤微生物碳、微生物氮、有机碳和全氮之间具有显著的正相关性（P＜0.01），微生物量磷与土壤有机碳和全磷具有极显著的正相关性（P＜0.01）。综合评价十数年后向家坝水电站工程扰动区人工修复土壤技术，植被混凝土和厚层基材修复措施对该区土壤全量养分含量的累积作用较好，框格梁样地的植物生长发育受到磷素营养的限制较大。     

Spatial analysis of soil resources in the Mewat district in the semiarid regions of Haryana,India

The soil characteristics are critical for crop health and its yield and therefore for agriculture. The soil properties are spatially variable and therefore soil resources should be managed as per location-specific requirements. An integrated spatial analysis of the soil resources of Mewat district was conducted to identify the soil resource management zones to develop site-specific soil management plan which might lead to sustained and enhanced crop yield. Spatial analysis of soil resources was conducted by modeling soil fertility and erosion which determines the crop productivity in the region. Soil fertility of the region was modeled using weighted overlay approach using 10 soil parameters, namely nitrogen, phosphorus, potassium, sulfur, iron, zinc, manganese, organic carbon, electrical conductivity, and pH. Each parameter was assigned weights based on their relative importance to agricultural productivity. The modeled soil fertility was classified into three fertility zones, low, medium, and high. Soil fertility was found to be low to moderate in 65% of the area, largely because of the low nitrogen, soil organic carbon, phosphorus concentration, and excessive salinity. Soil erosion was modeled using the universal soil loss equation (USLE) model by estimating rainfall erosivity factor (R), the soil erodibility factor (K), the topographic factors (L and S), cropping factor (C), and the conservation practice factor (P). Soil erosion problems were limited to areas having high elevation with barren land and areas with minimal management practices. The severity of soil erosion was found high in 15% of the region, while the remaining 85% showed low to moderate erosion. Soil fertility and erosion were integrated using the multivariate clustering method to identify soil management zones. The region was delineated into three soil management zones. Zone I (29%) which covers majorly Tarou block, was characterized by high soil fertility and low soil erosion. Zone II (18%) with medium soil fertility and high erosion covers villages of Taoru, Nuh, Nagina, FP Jhirka, and Punhana, which are located in the foothills of Aravalli ranges. Zone III represents the major part of the region, covering Nuh, Nagina, and FP Jhirka blocks (54%) with low soil fertility and erosion conditions. Thus, within the study area, the soil management domains are spatially variable in terms of fertility and soil erosion, and thus zone-specific soil management measures are required to improve the soil condition in order to sustain and improve agriculture production. The study would help the policy makers to design site-specific planning for identified soil resource management zones.