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8161. 题目: The impact of environmental policy on soil quality: Organic carbon and phosphorus levels in croplands and grasslands of the European Natura 2000 network
文章编号: N18062590
期刊: Journal of Environmental Management
作者: Andrea Hagyó, Gergely Tóth
更新时间: 2018-06-25
摘要: In this study, the Natura 2000 nature protection network of the European Union is assessed in the context of soil quality management. We explore the hypothesis that the soil quality of croplands and grasslands — as indicated by soil organic carbon and phosphorus levels — is better in terms of environmental parameters within the Natura 2000 network than outside it. The soil organic carbon and phosphorus content of 479 cropland and 450 grassland sites within Natura 2000 were compared with their nearest neighbours outside the network. The comparisons were repeated for pairs of both cropland and grassland sites by soil texture groups. The study revealed that organic carbon content was significantly higher in Natura 2000 sites than in non-protected areas for both croplands and grasslands. For croplands, this was true only for those with signs of ploughing, whereas for croplands without signs of ploughing there were no significant differences between Natura 2000 and non-protected areas. Areas with sand and loamy sand soils had significantly higher soil organic carbon content within the Natura 2000 network than outside it, for both croplands and grasslands. This was the only texture class that showed a significant difference in the case of croplands, whereas three further texture groups had higher soil organic carbon content in Natura 2000 grassland sites than on grassland sites outside this network. There was no significant difference in soil phosphorus content between areas within the Natura 2000 network and non-protected areas, except for grasslands with light textured soils, where soil phosphorus levels were significantly lower within Natura 2000 sites than outside them. The results suggest that the management of croplands and grasslands of Natura 2000 sites tends to perform better than that of adjacent areas with similar land cover in terms of soil carbon conservation. The difference is more evident for sites with certain soil characteristics. On the other hand, the nutrient input - as determined by phosphorus levels - of Natura 2000 croplands and grasslands generally does not appear to be less intensive than that of surrounding areas outside the network.

8162. 题目: Evaluation of water treatment capacity, nutrient cycling, and biomass production in a marine aquaponic system
文章编号: N18062589
期刊: Ecological Engineering
作者: Suzanne E. Boxman, Michael Nystrom, Sarina J. Ergas, Kevan L. Main, Maya A. Trotz
更新时间: 2018-06-25
摘要: The need to expand marine fish production and improve the economic viability and sustainability of recirculating aquaculture systems led to the development of a zero-discharge, marine aquaponic system. In this study, water treatment capacity, nutrient cycling, and biomass production were evaluated in a prototype, commercial-scale marine aquaponic system that included a moving bed bioreactor (MBBR) for nitrification, a sand filter for solids removal and denitrification, and hydroponic plant beds. Red drum (Sciaenops ocellatus), two species of edible halophytes sea purslane (Sesuvium portulacastrum) and saltwort (Batis maritima), and organic solids, were successfully produced over a 9-month period. Extensive analysis of solids, organic matter, and nutrients (nitrogen and phosphorous) in water and plant biomass was used to develop detailed mass balances on the system. Simultaneous operation of the moving bed bioreactor (MBBR) and plant beds resulted in high ammonia removal rates, allowing the system to support a high fish biomass density (38.8 kg/m3). Passive denitrification was the main nitrate removal mechanism, contributing to approximately 59% of aqueous nitrogen removal. Conversion of a sand filter to a side-stream denitrification reactor resulted in removal of 17% of the daily aqueous nitrogen load and prevented nitrate accumulation in the system. In addition to fish and edible halophyte production, 34 kg of organic solids were harvested from the sand filter and provided to a commercial nursery that used the solids as a fertilizer. This study demonstrates that marine aquaponics is an effective way to simultaneously produce marine fish, edible halophytes, and fertilizer. Addition of biological MBBR and a denitrifying sand filter was shown to be beneficial in situations where there are space limitations for plant growth, unexpected plant losses, or to support high densities of fish.

8163. 题目: Performance of ornamental plants in monoculture and polyculture horizontal subsurface flow constructed wetlands for treating wastewater
文章编号: N18062588
期刊: Ecological Engineering
作者: Ana María Leiva, Romina Nú?ez, Gloria Gómez, Daniela López, Gladys Vidal
更新时间: 2018-06-25
摘要: The aim of this study was to evaluate the effect of two ornamental plants in monoculture and polyculture horizontal subsurface flow (HSSF) constructed wetlands for treating wastewater. Two pilot-scale HSSF systems each with a surface area of 4.5 m2 were operated over two years (2015 and 2016); a) one was planted with a mixture of Cyperus papyrus and Zantedeschia aethiopica (HSSF-Cyp/Zant), and b) the other was planted only with Cyperus papyrus (HSSF-Cyp). To compare the performance between monoculture and polyculture systems, in situ parameters and organic matter (chemical oxygen demand (COD) and biological oxygen demand (BOD5)), total suspended solids (TSS), nutrients (total nitrogen (TN) and total phosphorus (TP)) and pathogens (fecal coliform (FC) and total coliform (TC)) removal efficiencies were evaluated. Moreover, growth characteristics, biomass production and nutrients uptake of different plants used in HSSF systems were also compared. The removal efficiencies of organic matter, suspended solids, nutrients and pathogens during the operational years were above 60%, 90%, 10% and 1.8 Log most probable number (MPN)/100 mL, respectively, without significant differences between HSSF-Cyp/Zant and HSSF-Cyp. The biomass production and the density of both HSSF systems fluctuated between 19.7 and 21.5 kg dry weight (DW)/m2 and 454–684 individuals/m2. Regarding the nutrient content of different plants used, Zantedeschia aethiopica, which was planted in the polyculture system, had the highest TN and TP content in all plants tissues (59.6 g N/kg·DW and 8.28 g P/kg·DW, respectively). However, TN and TP mass balances determined that the effect of monoculture and polyculture systems was not significant. Despite these results, polyculture CWs represent a good alternative of treatment system because they provide social benefits to the community such the improving of the system landscape and a better habitat quality. Moreover, some authors reported that polyculture system enhance the resistance to environmental stress and disease and the system landscape.

8164. 题目: Relationship between groundwater levels and oxygen availability in fen peat soils
文章编号: N18062587
期刊: Ecological Engineering
作者: Jan Dickopp, Andreas Lengerer, Marian Kazda
更新时间: 2018-06-25
摘要: Groundwater levels (GWL) are a major controlling factor for aeration and organic matter turnover in wetland soils but little is known about this relationship under field conditions. This study tested how the O2 availability in fen peat soils is related to groundwater levels. The study encompassed five sites over a wide range of land use intensity. Ground water levels and soil oxygen saturation in 5 cm and 20 cm depth were measured biweekly in three replicates per site over periods of 2–3 years. The O2 levels were not linearly proportional to the GWL, but changed sharply from anoxic to nearly atmospheric levels depending on the positions of water table. Binary logistic regression analyses (LRA) were calculated for the individual sites in order to predict the threshold GWL for defined probabilities of hypoxic or oxic conditions in 5 cm depth. The GWLs for 95% probability of oxic conditions were markedly lower for the managed grasslands ( 116 cm and 89 cm to surface level, respectively) than for the unmanaged pasture and the sedge fen ( 60 cm and 38 cm). Hypoxic conditions required GWLs close to the surface (7 cm and 2 cm for the pasture and the restored site, respectively) while in 5 cm soil depth managed grasslands remained hypoxic even at GWLs of 8 cm and 28 cm. In 20 cm soil depth, full oxygen saturation never occurred even at GWL as low as 80 cm. Threshold GWL required for 95% probability of oxic conditions was higher with increasing porosity and rooting density. The offset between GWL and oxic conditions can be used for hydrological wetland management, especially for restoration efforts.

8165. 题目: Vermistabilization of paper mill sludge by an epigeic earthworm Perionyx excavatus: Mitigation strategies for sustainable environmental management
文章编号: N18062586
期刊: Ecological Engineering
作者: Ananthanarayanan Yuvaraj, Natchimuthu Karmegam, Ramasundaram Thangaraj
更新时间: 2018-06-25
摘要: The present study demonstrates the vermistabilization of paper mill wastewater sludge (PMS) spiked with cow dung (CD) employing indigenous epigeic earthworm Perionyx excavatus Perrier. A total of six treatments were prepared along with a positive control (PC) and negative control (NC). Twenty earthworms were released into each treatment including PC and NC without earthworms. The different proportions viz., T1 (CD – 100%), T2 (PMS:CD – 1:3), T3 (PMS:CD – 1:2), T4 (PMS:CD – 1:1), T5 (PMS:CD – 3:1), T6 (PMS:CD – 2:1), PC (PMS – 100%) and NC (PMS – 100%) and changes in chemical parameters and microbial properties were recorded during the course of 60 days. Vermistabilization caused a significant decrease in the level of heavy metals: Cd (2.9–27.8%), Cu (0.22–42.3%), Pb (1.3–56.3%) and Cr (0.8–46.2%). The bioconcentration factor (BCFs) was also calculated and great amount of heavy metals accumulated in their body (mg kg 1) that ranged from 0.31 ± 0.003–0.45 ± 0.007 for Cd, 0.12 ± 0.005–0.24 ± 0.003 for Cu, 0.15 ± 0.005–0.31 ± 0.006 for Pb and 0.29 ± 0.007–0.56 ± 0.001 mg kg 1 for Cr, accumulation of heavy metals are in the order: Cr > Cd > Pb > Cu. The physicochemical parameters of earthworm treated substrate such as electrical conductivity, total nitrogen, total phosphorus and total potassium were significantly increased; whereas, pH, total organic carbon, C:N ratio (carbon: nitrogen) and C:P ratio (carbon: phosphorus) were reduced after 60 days of vermistabilization. The vermistabilized materials also had a higher population of bacteria (98.90 ± 0.30 CFU × 106 g 1), fungi (43.75 ± 0.55 CFU × 103 g 1) and actinomycetes (67.65 ± 0.45 CFU × 105 g 1) than initial mixtures. Moreover, several histopathological changes were observed in earthworm tissues viz., disintegration of cells, irregular surface of epidermis, cellular debris, irregular cellular compartmentation, and oval-shaped nucleus. Higher level of histopathological abnormalities was recorded in PC (PMS-100%) while none were detected in lower concentrations of PMS. Furthermore, the study concludes that the paper mill sludge in a mixture of cow dung (1:1 ratio) can be a useful proposition for utilizing this hazardous waste through the adoption of vermitechnology.

8166. 题目: Changes in soil enzymes, soil properties, and maize crop productivity under wheat straw mulching in Guanzhong, China
文章编号: N18062585
期刊: Soil and Tillage Research
作者: Kashif Akhtar, Weiyu Wang, Guangxin Ren, Ahmad Khan, Yongzhong Feng, Gaihe Yang
更新时间: 2018-06-25
摘要: Addition of organic material, such as crop straw mulch in most soils is considered a strategy for sustainable agricultural production. We conducted a two-year experiment in 2015 and 2016 to determine changes in soil biochemical properties and maize yield in response to treatment with wheat-straw mulch. The treatments consisted of the addition of different levels of wheat-straw mulch (S1: 0, S2: 2500, S3: 5000 kg ha 1). Soil samples from four depths (0.1, 0.2, 0.3, and 0.4 m) were collected and analyzed. Soil enzymes, such as invertase, phosphatase, urease, and catalase, were significantly higher in the S3 treatment than in the S1 treatment. Values were greater for the samples collected at 0.1 m soil depth than those collected from deeper soil layers. Regarding soil properties, soil organic carbon (SOC), available nitrogen (AN), available phosphorus (AP), total nitrogen (TN), total phosphorus (TP), and soil water content (SWC) were significantly higher in S3 at 0–0.1 m soil depth than in other treatments. Compared with the (S1), an average increase in SOC, AN, AP, TN, TP, and SWC in 0–0.4 m soil depth with full straw mulch (S3), were 32.4, 31.9, 32.0, 11.8, 16.7, and 18.5%, higher, respectively. On average, urease, phosphatase, invertase, and catalase increased by 15.1, 11.0, 88.4, and 24.0%, respectively in the S3 treatment compared with that in the S1 treatment at 0–0.1 m depth, and decreased with increasing soil depth. The S3 treatment had increased grain yield (7%), biomass yield (28%), and water use efficiency (8%), compared with the S1 treatment. Overall, our results suggested that the S3 straw mulch treatment (5000 kg ha 1) could be used to sustain maize productivity and promote a better relationship between soil enzymes and soil properties in the semi-arid conditions of the Guanzhong area.

8167. 题目: Characterization of the heavy, hydrolysable and non-hydrolysable fractions of soil organic carbon in conventional and no-tillage soils
文章编号: N18062584
期刊: Soil and Tillage Research
作者: Ravindra Ramnarine, Robert P. Voroney, Kari E. Dunfield, Claudia Wagner-Riddle
更新时间: 2018-06-25
摘要: Quantification of soil organic carbon (SOC) pool fractions under different tillage systems is important in understanding SOC dynamics and storage. Two major pools of SOC that can be isolated are the light (LF) and heavy fractions (HF). Few studies have quantified the effect of tillage systems on the hydrolysable (HYF) and non-hydrolysable fractions (NHF) which comprise the HF. The objective of this study was to evaluate if there were significant changes in the quantity and δ13C of the HF, HYF, and NHF fractions of SOC after six years of no-tillage (NT), on arable soils that were previously under conventional tillage (CT). Our study used 13C natural abundance (rotation of C3 and C4crops) on a calcareous Typic Hapludalf soil in southern Ontario, Canada. The HF (>1.7 g cm 3) was isolated using density fractionation and separated into its HYF and NHF using acid hydrolysis (6 M HCl) for three soil depths: 0–10, 10–20, and 20–30 cm. The HF pool (90–93% of SOC) was significantly greater (P < 0.05) in the NT (28.9) than the CT system (25.5 Mg C ha 1) only for the 0–10 cm depth. The dominant SOC fraction from the HF pool was the NHF (62–65% of SOC) for both tillage systems. However, the HYF (25–30% of SOC) was significantly greater in the NT (9.3) than the CT system (7.0 Mg C ha 1) only for the 0–10 cm depth. Additionally, there was a significantly higher proportion of C4-derived C in the HF only at the 0–10 cm depth of NT soils. Differences in the δ13C of the whole soil and SOC fractions show a preservation of newly derived C in the HF, HYF and NHF of NT soils. We conclude that the adoption of NT systems on arable soils increases the quantity of HF and HYF in the 0–10 cm depth only, but there is no difference in carbon sequestration potential when treatments are compared over the 0–30 cm depth in the short-term.

8168. 题目: Consolidation and surface sealing of nine harrowed Swedish soils
文章编号: N18062583
期刊: Soil and Tillage Research
作者: Maria Sandin, Nicholas Jarvis, Mats Larsbo
更新时间: 2018-06-25
摘要: The structure of agricultural topsoils varies considerably throughout the year due to interactions between climatic and biological factors and agricultural management practices. Tillage generally decreases soil density and increases macroporosity, but the resulting arrangement of clods and aggregates is unstable and the soil eventually reverts back to its denser pre-tillage condition. Accounting for post-tillage changes in soil structure and related hydraulic properties could greatly improve model predictions of hydrological and transport processes. Model testing, development and parameterization is, however, currently hampered by a lack of direct measurements of the changes occurring in the structural pore system. We subjected repacked samples of soil collected from the harrowed layer of nine different fine- and medium-textured Swedish mineral soils to subsequent wetting and drying cycles in the laboratory. Initial wetting and equilibration at 30 cm pressure potential was followed by three cycles of simulated rainfall (5 mm h 1 for 4 h) and equilibration. X-ray tomography was used to quantify changes in surface and total porosity, pore size distribution (PSD) and connectivity of structural pores. Total porosity decreased (by 2–24%) in all soils except for two clay soils where in one case the porosity increased slightly (3%) and remained unchanged in the other. In six of the soils, the PSD shifted significantly towards smaller pore sizes, and in four of these soils the connectivity of the pore network decreased. Soil surface porosity decreased most markedly in two silt loam soils (by 73% and 75%). For the nine soils changes were strongly correlated with silt content. Only weak correlations were found between the changes in total porosity and soil texture and organic carbon content. Changes in the PSD appeared to be mainly controlled by the initial structure of the sample created at the time of tillage and sample preparation.

8169. 题目: Crop yield, weed infestation and soil fertility responses to contrasted ploughing intensity and manure additions in a Mediterranean organic crop rotation
文章编号: N18062582
期刊: Soil and Tillage Research
作者: Paola Baldivieso-Freitas, José M. Blanco-Moreno, Laura Armengot, Lourdes Chamorro, Joan Romanyà, Francisco Xavier Sans
更新时间: 2018-06-25
摘要: Conservation agriculture and organic farming are two alternative strategies that aim to improve soil quality and fertility in arable cropping systems through reducing tillage intensity, maintaining soil cover and increasing nutrient recycling, using farmyard and green manures. However, these practices can increase weed infestation or decrease nutrient availability. The objectives of this study were to evaluate the effects of tillage type (mouldboard vs. chisel ploughing), fertilization and green manure on soil parameters (SOC, N, bulk density, carbon stocks, and soil microbial biomass Cmic and Nmic), weed abundance and crop yields in a four-year rotation of spelt, chickpea, winter wheat and lentil in the Mediterranean region (Catalonia, Spain). Tillage and green manure did not affect crop yields or weed biomass, although during the last year of the experiment, plots with mouldboard ploughing had less weed biomass and higher lentil biomass. Fertilization was the most important factor, increasing the cereal yields, SOC, N and soil microbial biomass (Cmic and Nmic) content of the soil. However, fertilization did not favour chickpea and lentil crops because weed competition limited legume crop growth. Overall, there was a loss of SOC and a reduction of carbon stocks over the four years of the trial in the soil because of the deep soil tillage (25 cm) and low crop productivity irrespective of tillage type. In contrast, N content increased in all of the plots and was enhanced by fertilization. The use of chisel plough stratified the distribution of SOC and N in the surface layers (0–10 cm). Both Cmic and Cmic/SOC ratio increased in fertilized treatments, suggesting an increased lability of SOC. The application of more stabilized organic matter may be a better practice to build up soil organic matter and to maintain crop yields in organic farming systems.

8170. 题目: Effect of land use, time since deforestation and management on organic C and N in soil textural fractions
文章编号: N18062581
期刊: Soil and Tillage Research
作者: Alexandros Eleftheriadis, Francisco Lafuente, Maria-Belén Turrión
更新时间: 2018-06-25
摘要: Deforestation and subsequent cultivation practices often result in loss of soil organic matter, in a degree depending on time since deforestation and soil and crop management. A land in North Greece was studied in order to check the influence of land use and management on soil organic C (SOC) and N. Cultivated soils with three dates since deforestation (25, 34 and 72 years) were compared to adjacent undisturbed forest soils. Two management systems were used in the cultivated soils: not irrigated wheat with superficial ploughing and irrigated cotton crop with deeper ploughing alternated with wheat every two years. Soil samples were separated in textural size fractions and organic C and N were analysed. In terms of land use, the most distinctive differences between agricultural and forest plots were found in coarse particulate organic matter (2.8 g kg 1 soil in agricultural land vs 14.8 g kg 1 soil in forest sites), and in the fine sand fraction SOC (8.6 g kg 1 soil in agricultural land vs 40.6 g kg 1 soil in forest sites), and N (1 g kg 1 soil in agricultural land vs 2.4 g kg 1 soil in forest sites), with minimal differences in the clay fraction (15.5 g kg 1 soil in agricultural land vs 21.2 g kg 1 soil in forest sites for SOC, and 2.2 g kg 1 soil in agricultural land vs 2.4 g kg 1 soil in forest sites for N). Time as a factor was significant for all the studied properties regarding the first years following deforestation. Management practices had an effect on SOC and, more pronounced, on N, with the wheat plots showing higher contents. Clay particles present the most stable behavior in terms of SOC (especially regarding time and management as factors) and N (especially regarding land use and time as factors) protection and maintenance.

8171. 题目: Effects of biochar on spatial and temporal changes in soil temperature in cold waterlogged rice paddies
文章编号: N18062580
期刊: Soil and Tillage Research
作者: Yuxue Liu, Shengmao Yang, Haohao Lu, Yuying Wang
更新时间: 2018-06-25
摘要: Soil temperature is an important factor constraining plant growth, large fluctuations of which generally result in low crop yield. However, the investigation of the effect of biochar on soil temperature, especially in cold waterlogged paddies, has been limited. This study investigated the effect of bamboo biochar (BB), rice straw biochar (RB), and rice straw (RS) on temporal variations in soil temperature at different depths, compared with no exogenous organic matter amendment soil as control treatment (CK), in a cold waterlogged paddy in Zhejiang Province, China. A logger with probes was used to record soil temperatures at the depths of 5 cm, 10 cm, and 20 cm at 08:00 h, 14:00 h, and 22:00 h daily from July 1 to Oct 31, 2012. Soil physicochemical properties and rice yield were analyzed after the harvest. The results showed that the application of BB and RB significantly reduced the soil temperature at 5- and 10-cm depths by 0.11 °C–0.21 °C on average, whereas RS significantly reduced soil temperature at a 5-cm depth by 0.19 °C and increased the average temperature at a 20-cm depth by 0.06 °C. Moreover, the average soil temperature related to BB, RB, and RS treatment significantly increased at 08:00 h during the rice-growing season by 0.15 °C, 0.43 °C, and 0.52 °C and significantly decreased at 14:00 h by 0.51 °C, 0.73 °C, and 0.87 °C, respectively, as compared with that in CK. Overall, both biochar and RS reduced the differences between day and night soil temperatures by 0.66 °C–1.39 °C, thereby regulating diurnal soil-temperature fluctuations, especially at a 5-cm depth. The reduced differences were likely attributed to the relatively lower bulk density (8.87–17.1%) and higher water content (9.75–14.3%) in the biochar-amended soil as compared with that in control soil. Furthermore, RB had a significant stronger positive effect on grain yield than BB, because it regulated soil temperature more effectively. These results suggested the feasibility of applying RB to cold waterlogged paddies to improve soil properties and crop yield.

8172. 题目: Effects of biological soil crusts on some physicochemical characteristics of rangeland soils of Alagol, Turkmen Sahra, NE Iran
文章编号: N18062579
期刊: Soil and Tillage Research
作者: Jalil Kakeh, Manouchehr Gorji, Mohammad Sohrabi, Ali Tavili, Ahmad Ali Pourbabaee
更新时间: 2018-06-25
摘要: Salinity, water scarcity in the summer season, and grazing pressure are major problems in semi-arid ecosystems in the south-east region of the Caspian Sea where the Alagol rangelands of Turkmen Sahra (Golestan province) of North East Iran suffer from over-grazing and soil loss. This study investigated the influence of biological soil crusts (biocrusts) on soil physicochemical properties. Biocrusts create complex communities of specialized organisms composed of cyanobacteria, algae, microfungi, lichens, mosses and other microorganisms. Results have shown that bioencrusted soils increased levels of organic carbon, nitrogen, phosphorus, copper, and iron, and reduced pH, calcium carbonate, sodium, calcium, magnesium, sodium adsorption ratio and exchangeable sodium percentages compared to soils without biocrusts. Other positive influences of biocrusts on soil properties included increased infiltration (0.16 v. 0.081 cm min 1 for steady state rates), available water content, mean weight diameter of soil aggregates, geometric mean diameter and water stable aggregates. Bulk density was reduced under bioencrusted soils relative to non-biocrusts soils. In general, biocrusts had a positive effect on many soil properties and thus enhanced soil quality.

8173. 题目: Grass cultivation alters soil organic carbon fractions in a subtropical orchard of southern China
文章编号: N18062578
期刊: Soil and Tillage Research
作者: Hui Wei, Kun Zhang, Jiaen Zhang, Dengfeng Li, Yuan Zhang, Huimin Xiang
更新时间: 2018-06-25
摘要: Understory management is evidently important for improving the ecological and economic effects of orchards, and grass maintenance in orchards is a potentially preferable floor management measure relative to clean tillage. It is widely accepted that grass maintenance increases soil organic carbon (SOC) content, but whether different SOC fractions respond consistently is less understood. To clarify the potential effects of grass maintenance on SOC fractions, three grass species, including a leguminous species (Stylosanthes guianensis cv. Reyan) and two gramineous species (Paspalum notatum Alain ex Flugge. and Pennisetum americanum x P. purpureum), were planted under young Litchi trees in a subtropical orchard of southern China for eight months using clean tillage as a control. The labile and non-labile SOC fractions and microbial C mineralization were investigated. Relative to the control, grass cultivation significantly increased or trended to increase the SOC content and this was mainly due to increases in the labile SOC fractions. The increased C lability and substrate supply support higher soil microbial biomass C, consequently accelerating the soil C mineralization process and resulting in a greater biologically mineralizable C pool. However, grass cultivation significantly decreased the non-readily oxidizable OC content, although it was relatively more chemically recalcitrant. Our results suggest that grass cultivation may favorably accelerate nutrient cycling in orchards due to higher labile C substrate availability and soil microbial biomass and activity. Nevertheless, grass cultivation could decrease SOC stabilization as indicated by the increased SOC lability in the grass-planting systems.

8174. 题目: Impact of reduced tillage on CO2 emission from soil under maize cultivation
文章编号: N18062577
期刊: Soil and Tillage Research
作者: Beata Rutkowska, Wies?aw Szulc, Tomasz Sosulski, Monika Skowrońska, Jan Szczepaniak
更新时间: 2018-06-25
摘要: Carbon dioxide is an important greenhouse gas, which is released through human activities such as deforestation, burning fossil fuels, agriculture, and degradation of soil. The type of soil tillage systems has a very important impact on soil CO2 emissions. Usually higher soil CO2 emission have been observed under conventional tillage compared to reduced tillage. Maize is one of the main cereals grown around the world that reacts positively on conservation tillage. We hypothesized that reduced tillage with sub-soil fertilizer application could increase maize yield and reduce carbon emissions compared to conventional plowing. Therefore we studied CO2 emissions from soil under a conventional and innovative, environmentally safe, low-cost maize production system dedicated both to reduce time and resources and to manage the field sustainably with a lower CO2 footprint. We observed that the magnitude of grain yield depended on soil and climate conditions but not on the cultivation system. The CO2 emission level depended on the year of the study and the soil tillage method and was subject to considerable changes during the growing season. The use of reduced soil tillage significantly limited emissions of the analyzed gas into the atmosphere. Depending on the year of the study, CO2 emissions in the reduced tillage system were 7 to 35% lower than those in the conventional system. The extent of the reduction in CO2 emissions achieved under reduced tillage is very large relative to conventional tillage, which is probably due to the relatively low organic matter content of the both investigated soils in the conventional tillage. We could show that on sandy soils with a low organic matter content reduction in tillage is a factor significantly diminishing CO2 emissions.

8175. 题目: Irrigation induced surface carbon flow in a Vertisol under furrow irrigated cotton cropping systems
文章编号: N18062576
期刊: Soil and Tillage Research
作者: Gunasekhar Nachimuthu, Nilantha R. Hulugalle, Mark D. Watkins, Lloyd A. Finlay, Bruce McCorkell
更新时间: 2018-06-25
摘要: Pathways of sequestered carbon loss from cotton (Gossypium hirsutum L.) farming systems include the carbon transported off-site in runoff and erosion. There is a lack of field studies that quantify the carbon gains and losses in hydrological pathways in cotton and other irrigated row cropping systems A three-year field investigation was overlaid on a long-term experiment near Narrabri, New South Wales, Australia with the objective to evaluate the effect of tillage practices and crop rotations on carbon loads in irrigation and runoff waters, and their impact on soil carbon balance in an intensive cotton production system. The treatments included maximum or minimum tillage sown with cotton monoculture, cotton-wheat (Triticum aestivum L.) or cotton-maize (Zea mays L.) rotations. Maximum tillage consisted of slashing of cotton plants after harvest, followed by disc-ploughing to incorporate the cotton stalks to 0.2 m, followed by chisel ploughing to 0.3 m, then 1 m bed construction. For minimum tillage, slashing was followed by root cutting, then incorporation of cotton stalks into beds (0.1 m) and followed by bed renovation with a disc-hiller. The minimum-tilled cotton-wheat rotation included similar tillage operations after cotton, however maize or cotton was planted into standing wheat stubble with zero tillage. Irrigation volume, sediment, and total and dissolved organic carbon gains and losses during irrigation were monitored during the 2014–15, 2015–16 and 2016–17 cotton seasons. Runoff from maximum-tilled and minimum-tilled cotton monoculture systems averaged 32% and 40%, respectively, of applied irrigation. Irrigation-induced total organic carbon (TOC) losses in runoff from the cotton field were influenced by tillage during 2015–16 and ranged from 24 to 72 kg ha 1 year-1 across three years. Net TOC enrichment of cotton field soils by irrigation water ranged from 30 to 265 kg TOC ha-1. Overall, the average seasonal net carbon gains in irrigation water were equivalent to mitigating 4.7 to 24% of long term annual soil organic carbon (SOC) decline rate in the same experiment. Storm events intensified the movement of carbon and soil from bed to furrows. These sediments were prone to further erosion during subsequent irrigations. Minimum tillage can minimise carbon losses in runoff when combined with a crop sequence such as cotton-wheat-maize. Consequently, research on soil carbon sequestration in irrigated systems must account for carbon flow during irrigation because it is a significant factor in the carbon balance. Long term monitoring over several years is needed to quantify storm-induced carbon losses in semi-arid limited rainfall environments.

8176. 题目: Microaggregate stability and storage of organic carbon is affected by clay content in arable Luvisols
文章编号: N18062575
期刊: Soil and Tillage Research
作者: Lars Krause, Andrei Rodionov, Steffen A. Schweizer, Nina Siebers, Eva Lehndorff, Erwin Klumpp, Wulf Amelung
更新时间: 2018-06-25
摘要: As soil microaggregates (<250 μm, SMA) usually withstand long-term tillage, we hypothesized that i) elevated clay contents in arable soil support aggregation already at microaggregate level, leading to ii) increasing organic carbon (SOC) enrichment in smaller SMA size fractions. To test these hypotheses we sampled the topsoil (5–20 cm) of Luvisols with a long history of agricultural management at the Scheyern experiment station (Germany) in quintuplicates from each of five subsites with different clay contents (19–34%). The field-fresh topsoil was fractionated into macroaggregates (8000–250 μm), large SMA (250–20 μm), and small SMA (<20 μm) and the mass distribution was recorded. In addition, the water stable macroaggregates (>250 μm) were dispersed ultrasonically to study occluded SMA and single building units. Finally, we analyzed the size distribution of the small SMA by laser diffraction analysis. The total mass distribution of free and occluded SMA grouped soils into those with small (19, 22, and 24%) and large (32 and 34%) clay contents. The finer textured soils exhibited larger portions of occluded SMA, with a gamma size distribution of small SMA peaking at 6 μm. Yet the occluded small SMA in the finer textured soils showed an additional enrichment of colloids <1 μm. The SOC was indeed enriched in finer fractions, but more in the small SMA of the coarse textured sites than in the finer textured ones, whereas the opposite was true for the large SMA. We conclude, therefore, that elevated contents of clay-sized particles promote SMA formation and stabilization, therewith shifting SOC enrichment from small to larger SMA.

8177. 题目: Mid-long term effects of no tillage and Ca-amendment on degraded acid soils under contrasting weather conditions
文章编号: N18062574
期刊: Soil and Tillage Research
作者: Chiquinquirá Hontoria, Clara Gómez-Paccard, Eduardo Vázquez, Ignacio Mariscal-Sancho, Rafaela Ordónez-Fernández, Rosa Carbonell-Bojollo, Rafael Espejo
更新时间: 2018-06-25
摘要: Inadequate soil management such as excessive ploughing is one of the main problems affecting the sustainability of agroecosystems and may exacerbate problems in acid soils. The application of Ca-amendments to ameliorate acid soils and no tillage practices to recover degraded soils are common management strategies. However, few studies have focused on their interactive effects under conditions of variable rainfall. In this study, we assessed the changes in soil properties over a period of seven years in response to no tillage (NT) and tillage, with or without the application of a Ca-amendment (sugar beet foam and red gypsum). Our split-plot experiment, which started in 2005 was carried out in a degraded Palexerult in Southwestern Spain with an annual rainfed forage crop. The Ca-amendment increased soil pH, Ca content and ameliorated Al-toxicity down to a depth of 50 cm, even under NT, due to the relatively high solubility of the amendment. However, after seven years of experiment, soil organic matter variables were enhanced only to a soil depth of 0–5 cm: NT and the Ca-amendment increased total organic carbon by 31% and 25%, respectively, whereas particulate organic carbon was increased to a larger extent (by a factor of 2.5 and 2, respectively). The positive effect of NT on organic matter variables increased with time, whereas the beneficial effect of the Ca-amendment was stronger in the early years of the experiment. Adverse weather conditions, with either excessive precipitation in autumn-winter or scarce precipitation in spring, favoured biomass production under NT. Given that NT mitigated the adverse effects of both water excess and deficit on biomass, it constitutes a valuable tool to combine with Ca-amendment to maintain crop productivity and recover degraded acid soils. This is especially the case under the changing weather conditions of a Mediterranean climate or other climates with increasing occurrences of periods of drought and/or water excess.

8178. 题目: Modeling soil organic carbon and carbon dioxide emissions in different tillage systems supported by precision agriculture technologies under current climatic conditions
文章编号: N18062573
期刊: Soil and Tillage Research
作者: Donato Cillis, Bernardo Maestrini, Andrea Pezzuolo, Francesco Marinello, Luigi Sartori
更新时间: 2018-06-25
摘要: Soil organic matter (SOM) represents the biggest pool of carbon within the biosphere and influences the flux of greenhouse gases between land surface and atmosphere. In this regard, conservation tillage systems have been adopted to reduce negative impacts of conventional tillage practices on greenhouse gases (GHG) emissions. However, the role of these techniques to increase carbon sequestration also depends upon soil features and climatic conditions, which is studied and managed by precision agriculture (PA) principles and technologies. Simulation models have shown to be useful tools to understand the interaction between soil, climate, genotypes and management practices to simulate the long-term effects of management approaches of different soils on crop yield, soil organic carbon (SOC) storage, and GHG emissions. The research goals of this study are (1) to examine the mid-term (15 years) trajectory of SOC in the upper 0.4 m of the soil profile under different tillage systems using the SALUS model; (2) determine the impact of PA on the inputs to the crop and CO2 emissions; (3) identify the strategies, derived from the synergy between conservation agriculture and PA, so as to decrease the CO2 emissions of agricultural systems. The validated SALUS simulation showed a significant reduction in SOC losses in minimum tillage (MT) and no-tillage (NT), 17% and 63% respectively, compared to conventional tillage (CT). Furthermore, the adoption of conservation tillage techniques decreased carbon emissions related to farming operations, while PA technologies led to an optimization of the exhaustible sources such as fossil fuels and fertilizers. Finally, the synergy between conservation tillage systems, especially NT, and PA strategies represents a useful tool in terms of carbon emissions mitigation with a reduction of 56% of total CO2 as compared to CT.

8179. 题目: Seasonal dynamics of the physical quality of volcanic ash soils under different land uses in southern Chile
文章编号: N18062572
期刊: Soil and Tillage Research
作者: Susana R. Valle, José D?rner, Felipe Zú?iga, Dorota Dec
更新时间: 2018-06-25
摘要: In Chile, volcanic soils were developed under almost all of the diverse rain and temperature regimes, from the Arid Mediterranean to the Wet Zone of the South. Due to their andic properties, volcanic soils exhibit characteristics that are entirely different from other soil types around the world. The soil physical quality (SPQ) is strongly related to the functions of the soil pore system. Thus, soils characterized by a good SPQ have the ability to store and conduct water, air and nutrients promoting both: maximum crop yield and minimum environmental degradation. Many studies and much scientific progress have been made concerning the storing and conducting of water and air functions in volcanic soils. However, soil physical quality indicators and their temporal changes have been less studied. Thus, the objectives of this study were: i) to assess the impact of land use changes on the physical quality of three main volcanic soil groups in Chile, ii) to quantify the magnitude of their temporal changes and iii) to compare these results with threshold values found in the literature. Three soils derived from volcanic materials formed under different conditions and with different degrees of development were sampled (with different intrinsic properties), on five sampling dates, under three land uses (intensities): native forest (NF), prairie (P) and crops (C). Undisturbed samples were taken at two soil depths: 0–15 cm and 15–30 cm, in 230 cm3 metallic cylinders, and then covered with caps and plastic film to prevent mechanical disturbance and evaporation. We measured and /or calculated from these samples: air capacity (AC), plant available water capacity (PAWC), relative field capacity (RFC), bulk density (dB), air conductivity (kl), pore connectivity indexes (C2 and C3), the coefficient of linear extensibility (COLE) and saturated hydraulic conductivity (Ks). Undisturbed soil blocks were collected to evaluate aggregate stability. To assess differences among land uses and seasons in the SPQ indicators, analyses of variance (ANOVA) were used and an LSD test (p ≤ 0.05) was conducted to separate the means. A principal component analysis (PCA) was performed to associate the SPQ indicators. The results of this study allow us to conclude that the impact on SPQ indicators depended on the soil type, considering their degrees of development, clay content and type, as well as the organic carbon content and the season in which the soil functions were determined. When values of the SPQ indicators were compared with critical and/or threshold values of the mineral soils found in the literature, the indicators of dB and RFC fell completely out of the range considered typical for mineral soils. Thus, several questions remain regarding the real critical values of these soil properties in volcanic soils. More work is necessary to establish the critical value of volcanic soil’s bulk density, since this is a widely used soil property that serves as an estimator of other functional soil quality indicators.

8180. 题目: Soil organic carbon, macro- and micronutrient changes in soil fractions with different lability in response to crop intensification
文章编号: N18062571
期刊: Soil and Tillage Research
作者: R. Romaniuk, M. Beltrán, L. Brutti, A. Costantini, S. Bacigaluppo, H. Sainz-Rozas, F. Salvagiotti
更新时间: 2018-06-25
摘要: Soils under no tillage have experienced unfavorable changes, mainly due to current agricultural practices that consist in monocultures that leave little residue cover. The inclusion of grass as cover crops during the winter season could be a sustainable strategy to increase crop intensification in sequences where soybean predominates, helping to maintain soil fertility, organic matter levels and enhance soil physical properties. The aim of this research was to evaluate the effects of 8 years of sustainable crop intensification (by increasing the proportion of cereals in crop rotations) on soil organic carbon, macro- and micronutrients associated with granulometric fractions of different lability in a Typic Argiudoll of the Rolling Pampa, Argentina. The experiment included two crop sequences commonly used in this area: soybean-soybean (S-S) and maize-soybean-wheat/soybean (M-S-W/S) combined with the inclusion of wheat (Triticum aestivum L.) as cover crop (CC) in winter. The intensification sequence indices (ISI) were 0.39, 0.69, 0.55 and 0.64 for S-S, S-CC-S, M-S-W/S and M-CC-S-W/S, respectively. The carbon measured in the coarse particulate fraction (Pcf) in the 0–5 cm soil depth was 3 times larger in S-CC-S than in S-S. Cropping intensity also modified N, S, P, Ca and Mn in the Pcf with no changes in Mg, K, Zn, Fe and Cu contents. Among the carbon fractions studied, only the carbon measured in the Pcf and the easy mineralizable carbon estimated by the soil respiration in the first soil layer (0–5 cm), were positively correlated with the ISI. In the present study, 8 years under sustainable crop intensification were sufficient to show changes in the mineral associated fraction (Maf). Increases in the C in the Maf in maize legume-based rotation, suggest SOC accumulation in more stable carbon pools.

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