1SZ-140/210型多功能振动式土壤改良机械

由黑龙江省水利科学研究所研制成功的1SZ-140/210型多功能振动式土壤改良机械,日前通过省级鉴定并投入批量生产。该土壤改良机有1SZ-140及1SZ-210型机两种,与37～59kW拖拉机配套,可完成松土、鼠道排水施工、果树断根以及根茎类作物和中药材的收获等作业。对于改良土壤、粘性土壤耕作、坡耕地保水保温以及促进牧场。

Mechanized Tunneling in Soft Soils： Choice of Excavation Mode and Application of Soil-Conditioning Additives in Glacial Deposits

The history of the formation of the alpine region is affected by the activities of the glaciers, which have a strong influence on underground works in this area. Mechanized tunneling must adapt to the presence of sound and altered rock, as well as to inhomogeneous soil layers that range from permeable gravel to soft clay sediments along the same tunnel. This article focuses on past experiences with tunnel-boring machines （TBMs） in Switzerland, and specifically on the aspects of soil conditioning during a passage through inhomogeneous soft soils. Most tunnels in the past were drilled using the slurry mode （SM）, in which the application of different additives was mainly limited to difficult zones of high permeability and stoppages for tool change and modification. For drillings with the less common earth pressure balanced mode （EPBM）, continuous foam conditioning and the additional use of polymer and bentonite have proven to be successful. The use of conditioning additives led to new challenges during separation of the slurries （for SM） and disposal of the excavated soil （for EPBM）. If the disposal of chemically treated soft soil mate- rial from the earth pressure balanced （EPB） drive in a manner that is compliant with environmental legislation is considered early on in the design and evaluation of the excavation mode, the EPBM can be beneficial for tunnels bored in glacial deposits.

Effect of Low-Molecular-Weight Organic Acids on Cl-Adsorption by Variable Charge Soils

Low-molecular-weight (LMW) organic acids exist widely in soils and have beenimplicated in many soil processes. The objective of the present paper was to evaluate effect of twoLMW organic acids, citric acid and oxalic acid, on Cl^-adsorption by three variable charge soils, alatosol, a lateritic red soil and a red soil, using a batch method. The results showed that thepresence of citric acid and oxalic acid led to a decrease in Cl^- adsorption with larger decreasesfor citric acid. Among the different soils Cl^- adsorption in the lateritic red soil and the redsoil was more affected by both the LMW organic acids than that in the latosol.

Biochar Applied with Organic Fertilizer Improves Alkaline Soil Properties and Crop Yield

Biochar(BC)is widely applied in agricultural production for its multiple uses such as carbon sequestration.However,application of BC alone has limited effect on soil fertility and crop yield,especially alkaline soil.Therefore,a pot experiment on Chinese cabbage(Brassica rapa var.glabra)was carried out in this study to investigate the effect of BC applied with organic fertilizer(OF)on alkaline soil properties and crop yield.To be specific,BC and OF were respectively applied at 0,1%,2%,and 3%,and Chinese cabbage was transplanted and cultivated for 2.5 months.Results showed that BC and OF increased the content of both organic matter and available P in alkaline soil(P<0.05).Moreover,the application of OF alone decreased the pH value but raised available N content of alkaline soil,and the application of only BC demonstrated the contrary effect(P<0.05).OF significantly improved crop yield(P<0.05),but the effect of BC was insignificant.Crop yield was the highest under the treatment of 1%BC and 3%OF.Thus,BC had limited effect on alkaline soil fertility and crop yield,but the application with OF was a good option for ameliorating alkaline soil and raising crop yield.

Effects of Soil Management on Changes of Soil Carbon Content in Alluvial Paddy Soil

Effects of soil management on carbon content in alluvial paddy were investigated using past soil survey data of Niigata prefecture, Japan. The changes of soil management were as follows： （1） slight decrease in nitrogen and phosphate fertilizer application rates; （2） decrease to half in the application of soil amendments, like calcium silicate; （3） decrease in compost application and increase in rice straw application; （4） increase in pipe drainage. In spite of these changes, negligible change of carbon content in the plow-layer of alluvial paddy soils had been observed for past 25 years. However, without rice straw application and paddy-upland rotations, the soil carbon content had been decreased. Carbon content of alluvial paddy soils classified into Gley Lowland soil （Fluvisol or Gleysol） at the depth of 0-30 cm was calculated about 49-103 g-kg＂1 and gross carbon sequestration was calculated 7.68 Mt in the paddy field soils in Niigata prefecture.

Impact of Organic Soil Amendments on the Physical Characteristics and Yield Components of Potato （Solanum tuberosurn L.） in the Highlands of Cameroon

A field experiment was conducted in the Western Highlands of Cameroon to study the effects of Calliandra calothyrsus, sterilized compost, non-sterilized compost and mineral fertilizers （NPK 11：11：22） on physical characteristics, yield components and late blight disease severity of potato （Solanum tuberosum）. A two factorial treatment combination made up of fertilization schemes and sanitary measures were laid out in a randomized complete block design （RCBD） with four replicates and 10 treatments. Data collected were subjected to a multivariate ANOVA and means separated with the Dunnett t-test with Calliandra calothyrsus considered as the main treatment. Mineral fertilizers and Calliandra calothyrsus significantly augmented stem diameter, plant height and plant vigor, total and marketable yields, despite the fact that late blight severity was high in the two treatments. The correlation matrix showed that total yield had significant and positive correlation with stem diameter （r = 0.74）, plant height （r = 0.61）, plant vigor （r = 0.61） and marketable yield （r = 0.99） and negative correlation （r = -37） with late blight severity. The increase observed is attributed to the nutrient contents of the treatments applied. Leafy prunings of C. calothyrsus increase soil organic matter which probably improves moisture retention and biological activity. The highest late blight severity recorded between the 45 and 60 coincides with active development of plant canopy which influences disease severity and create a canopy microclimate conducive to disease development. This study suggests that Calliandra calothyrsus has the potential of improving potato production provided appropriate fungicide is used.

Inhibition and Control Effects of Different Amendments on Cd Activation in Soil and Cd Absorption in Rice

Through pot tests of early rice and late rice in Cd polluted environment(soil Cd content,1.0 mg/kg),the inhibition and control effects of single application of organic fertilizers involving pig manure and biochar,and their combined application with alkaline amendments involving lime and oyster shell powder on soil Cd activation and rice Cd absorption were compared.And the correlation between soil available Cd and rice grain Cd was discussed.The results showed that compared with CK which did not involve amendments,the grain yields of early rice and late rice increased by 15.52%~36.01%and 12.02%~27.28%,respectively,the grain Cd content decreased by 24.76%~64.53%and 4.93%~58.32%,respectively,and the grain Cd accumulation decreased by 22.27%~51.76%and 33.84%~46.95%,respectively,except for single pig manure treatment.In particular,the Cd reduction effect of biochar was significantly better than that of pig manure,and the combined application with oyster shell powder was better than that with lime;after the harvest of early and late rice,the available Cd content in soil applied with amendments decreased by 35.00%~65.88%and 30.93%~68.57%,respectively,compared with CK.Further analysis showed that the soil available Cd content and rice grain Cd content could fit the linear equation well(R2>0.70,P<0.05),which demonstrated that the combined application of organic fertilizers and alkaline amendments can quickly reduce the Cd content of rice grain by passivating soil available Cd,and the combined application between biochar and oyster shell powder had a better effect.

Biochar-Induced Changes in Soil Resilience:Effects of Soil Texture and Biochar Dosage

Biochars are, amongst other available amendment materials, considered as an attractive tool in agriculture for carbon sequestration and improvement of soil functions. The latter is widely discussed as a consequence of improved physical quality of the amended soil.However, the mechanisms for this improvement are still poorly understood. This study investigated the effect of woodchip biochar amendment on micro-structural development, micro-and macro-structural stability, and resilience of two differently textured soils,fine sand(FS) and sandy loam(SL). Test substrates were prepared by adding 50 or 100 g kg^(-1) biochar to FS or SL. Total porosity and plant available water were significantly increased in both soils. Moreover, compressive strength of the aggregates was significantly decreased when biochar amount was doubled. Mechanical resilience of the aggregates at both micro-and macro-scale was improved in the biochar-amended soils, impacting the cohesion and compressive behavior. A combination of these effects will result in an improved pore structure and aeration. Consequently, the physicochemical environment for plants and microbes is improved. Furthermore, the improved stability properties will result in better capacity of the biochar-amended soil to recover from the myriad of mechanical stresses imposed under arable systems, including vehicle traffic, to the weight of overburden soil. However, it was noted that doubling the amendment rate did not in any case offer any remarkable additional improvement in these properties, suggesting a further need to investigate the optimal amendment rate.

Surface Amendments Can Ameliorate Subsoil Acidity in Tea Garden Soils of High-Rainfall Environments

Strongly acidic soils （pH 〈 5.0） are detrimental to tea （Camellia sinensis） production and quality. Little information exists on the ability of surface amendments to ameliorate subsoil acidity in the tea garden soils. A 120-d glasshouse column leaching experiment was conducted using commonly available soil ameliorants. Alkaline slag （AS） and organic residues, pig manure （PM） and rapeseed cake （RC） differing in ash alkalinity and C/N ratio were incorporated alone and in combination into the surface （0-15 cm） of soil columns （10 cm internal diameter x 50 cm long） packed with soil from the acidic soil layer （15-30 cm） of an Ultisol （initial pH -- 4.4）. During the 120-d experiment, the soil columns were watered （about 127 mm over 9 applications） according to the long-term mean annual rainfall （1 143 mm） and the leachates were collected and analyzed. At the end of the experiment, soil columns were partitioned into various depths and the chemical properties of soil were measured. The PM with a higher C/N ratio increased subsoil pH, whereas the RC with a lower C/N ratio decreased subsoil pH. However, combined amendments had a greater ability to reduce subsoil acidity than either of the amendments alone. The increases in pH of the subsoil were mainly ascribed to decreased base cation concentrations and the decomposition of organic anions present in dissolved organic carbon （DOC） and immobilization of nitrate that had been leached down from the amended layer. A significant （P 〈 0.05） correlation between alkalinity production （reduced exchangeable acidity - N-cycle alkalinity） and alkalinity balance （net alkalinity production - N-cycle alkalinity） was observed at the end of the experiment. Additionally, combined amendments significantly increased （P ~ 0.05） subsoil cation concentrations and decreased subsoil A1 saturation （P 〈 0.05）. Combined applications of AS with organic amendments to surface soils are effective in reducing subsoil acidity in high-rainfall areas. Further investigations under field conditions and over longer timeframes are needed to fully understand their practical effectiveness in ameliorating acidity of deeper soil layers under naturally occurring leaching regimes.

Plant Cover and Soil Biochemical Properties in a Mine Tailing Pond Five Years After Application of Marble Wastes and Organic Amendments

Tailing ponds pose environmental hazards, such as toxic metals which can contaminate the surroundings through wind and water erosions and leaching. Various chemical and biochemical properties, together with extractable and soluble metals were measured five years after reclamation of a polluted soil affected by former mining activities. This abandoned mine site contains large amounts of Fe-oxyhydroxides, sulphates, and heavy metals. As a consequence, soils remain bare and the soil organic matter content is low （〈 3 g kg-1）. Marble waste, pig manure and sewage sludge were applied in 2004. Plant cover and richness, and soil chemical, biochemical and biological parameters were analysed five years later. Results showed that all soil biochemical properties as well as vegetation cover and richness were higher in treated soils than in the untreated contaminated plots （control）, although organic matter, pH values and extractable metals concentrations were similar among treatments. Soluble cadmium and zinc were lower in the amended plots than in control.

Biochar for Sustainable Soil Health:A Review of Prospects and Concerns

Biochar as a soil amendment is confronted with the challenge that it must benefit soil health as it can be by no means separated from soils once it is added. The available literature even though sparse and mostly based on short-term studies has been encouraging and the trend obtained so far has raised many hopes. Biochar has been reported to positively impact an array of soil processes ranging from benefiting soil biology, controlling soil-borne pathogens, enhancing nitrogen fixation, improving soil physical and chemical properties,decreasing nitrate(NO-3) leaching and nitrous oxide(N2O) emission to remediation of contaminated soils. However, very little biochar is still utilized as soil amendment mainly because these benefits are yet to be quantified, and also the mechanisms by which the soil health is improved are poorly understood. Due to the infancy of research regarding this subject, there are still more questions than answers. The future research efforts must focus on carrying out long-term experiments and uncover the mechanisms underlying these processes so that key concerns surrounding the use of biochar are addressed before its large scale application is recommended.

Natural Organic Amendments for Improved Phytoremediation of Polluted Soils:A Review of Recent Progress

Environmental pollution caused by metals, radionuclides and organic pollutants affects quality of the biosphere: soil, water and air.Currently, great efforts have been made to reduce, remove or stabilize contaminants in polluted sites. There has been increasing interest in phytoremediation—the use of plants to reduce concentration of pollutants or to render them harmless. This paper provides a brief review of recent progress in the research and practical application of phytoremediation techniques. Improvements in phytoremediation due to utilization of organic amendments, namely, agro- and industrial wastes(such as sugar beet residue, composted sewage sludge or molasses), biochar, humic substances, plant extracts and exudates are discussed, as well as their influences on soil structure and characteristics, plants growth and bioavailability of pollutants. Both plant-assisted phytoremediation and the use of natural materials in the absence of remediating plant are believed to be cost-effective and environmentally friendly approaches for soil cleanup. However,the characterization and quantification of a range of natural materials used in phytoremediation are essential in order to implement these approaches to practice.

Immobilization of Lead and Cadmium in Contaminated Soil Using Amendments: A Review

Since the inception of industrial revolution, metal refining plants using pyrometallurgical processes have generated the prodigious emissions of lead(Pb) and cadmium(Cd). As the core target of such pollutants, a large number of soils are nowadays contaminated over widespread areas, posing a great threat to public health worldwide. Unlike organic pollutants, Pb and Cd do not undergo chemical or microbial breakdown and stay likely in site for longer duration after their release. Immobilization is an in-situ remediation technique that uses cost-effective soil amendments to reduce Pb and Cd availability in the contaminated soils. The Pb and Cd contamination in the soil environment is reviewed with focus on source enrichment, speciation and associated health risks, and immobilization options using various soil amendments. Commonly applied and emerging cost-effective soil amendments for Pb and Cd immobilization include phosphate compounds, liming, animal manure, biosolids, metal oxides, and biochar. These immobilizing agents could reduce the transfer of metal pollutants or residues to food web(plant uptake and leaching to subsurface water) and their long-term sustainability in heavy metal fixation needs further assessment.

Long-Term Effects of Inorganic and Organic Amendments on Organic Carbon in a Paddy Soil of the Taihu Lake Region,China

A long-term experiment set up in 1980 compared the effects of applying manures and chemical fertilizers on a paddy soil in the Taihu Lake region, China. Of the fourteen randomly distributed treatments consisting of different combinations of organic manure, inorganic nitrogen （N）, phosphorus （P）, and potassium （K）, and rice straw, eight were selected for the present study in 2007. Application of organic manure plus straw significantly increased soil organic carbon （SOC） content of the topsoil （0-10 cm） compared to that of chemical fertilizers alone. The content of SOC was relatively stable in the 10-30 cm layer in the chemical fertilizer treatments and in the 20-40 cm layer in the manure treatments. The stable carbon isotope ratio （513C） ranged from -24% to -28% and increased gradually with depth. The content of SOC was significantly （P 〈 0.05） negatively correlated with 513C. In the 0-20 cm layer, the 513C value significantly decreased in the treatments of manure alone （M）, manure and chemical N and P fertilizers （MNP）, manure and chemical N, P, and K fertilizers （MNPK）, manure, rice straw, and chemical N fertilizer （MRN）, and chemical N fertilizer and rice straw （CNR）, as compared with the no-fertilizer control. In the 30-50 cm layer, however, the ratio significantly increased in all the treatments except Treatment CNR. Mineralization of organic C peaked in the first 2-4 d of incubation and gradually leveled off thereafter over the first 3 weeks, being faster in the manure treatments than the chemical fertilizer treatments. The average rate of mineralization varied from 55.36 to 75.46 mL CO2 kg-1 d-1 and that of stable mineralization from 10 to 20 mL CO2 kg-1 d-1. In eight weeks of incubation, cumulative mineralization was always higher in the manure treatments than the chemical fertilizer treatments, being the highest in Treatment MRN. Combined humus in the soil was mainly （over 50%） composed of tightly combined fraction. The loosely combined humus and its ratio of humic acid （HA） to fulvic acid （FA） significantly increased with long-term application of organic manure and chemical fertilizers. It could be concluded that the cycle of organic C in the paddy soil ecosystem studied was stable over the long-term application of fertilizers and continued cultivation.