泥浆土壤特性动态检测(英文)

[Objective] The research aimed to provide basic files and theoretical guidance for constructing sluicing-siltation dam using soil with high clay content soil.[Method] The soils of Dagou basin near Xiwu Village of Baishui County,Shaanxi Province were taken as experimental materials.pvc pipes with same height and diameter were used to construct testing model for dynamically determining settlement,shear strength,wet density of grouting bulk under 2 different grouting speeds(15 cm/d and 25 cm/d).[Result] Under different grouting speeds,general change trend was similar during grouting course.The subsidence,deformation,shear strength and wet density increased with the increase of grouting speed.Five or six days after grouting,daily displacement under 25 cm/d grouting speed was fewer than that under 15 cm/d grouting speed.[Conclusion] The increase of grouting speed could shorten the time for reaching the same subsidence,deformation,shear strength and wet density and increased displacement at the initial stage of grouting,however,with the increase of grouting time,lower grouting bulk was bad for displacement at later grouting period because it was near impermeable layer.     

Dynamic Monitoring of the Mud

[Objective] The research aimed to provide basic files and theoretical guidance for constructing sluicing-siltation dam using soil with high clay content soil.[Method] The soils of Dagou basin near Xiwu Village of Baishui County,Shaanxi Province were taken as experimental materials.pvc pipes with same height and diameter were used to construct testing model for dynamically determining settlement,shear strength,wet density of grouting bulk under 2 different grouting speeds(15 cm/d and 25 cm/d).[Result] Under different grouting speeds,general change trend was similar during grouting course.The subsidence,deformation,shear strength and wet density increased with the increase of grouting speed.Five or six days after grouting,daily displacement under 25 cm/d grouting speed was fewer than that under 15 cm/d grouting speed.[Conclusion] The increase of grouting speed could shorten the time for reaching the same subsidence,deformation,shear strength and wet density and increased displacement at the initial stage of grouting,however,with the increase of grouting time,lower grouting bulk was bad for displacement at later grouting period because it was near impermeable layer.     

Effects of Subsoiling on Soil Moisture Under No-Tillage for Two Years

In order to improve the water use efficiency under conservation tillage, the effects of subsoiling on soil moisture under notillage were studied. An experiment of 40 cm subsoiling in a field kept under no-tillage for 2 years was operated from 2005 to 2006. Based on the data of the soil moisture and crop yield, the physical basis of subsoiling for water conservation and yield increase was analyzed. The results showed that the soil water storage under subsoiling, from the soil surface to a depth of 100 cm was more than that under no-tillage for the growth season. In the 0-100 cm soil depth, the soil moisture in 50-100 cm depth under subsoiling was more compared with no-tillage, which increased when it＇s drought and decreased when it＇s rainy with the increase in soil depth. Compared with no-tillage, subsoiling could reduce the water consumption of oats in the 0-50 cm depth and increase the water consumption in the 50-100 cm depth. Also, subsoiling increased the yield by 18.29% and the water use efficiency by 16.8% in a two-year average. The effects of subsoiling on water conservation and yield increase were affected by precipitation, and a well-proportioned rainfall was better to increase yield and water use efficiency. Meanwhile, subsoiling decreased bulk density, which increased with the available precipitation. Subsoiling under no-tillage is the effective rotation tillage to contain more soil moisture and improve water use efficiency in ecotone of North China.     

Cultivating Erect Milkvetch (Astragalus adsurgens Pall.) (Leguminosae) Improved Soil Properties inLoess Hilly and Gulliesin China

Erect milkvetch (Astragalus adsurgens Pall.), a leguminous grass, is a major source of fuel and forage, and has an important role in the restoration of the degraded ecosystems in central and northeastern China. The objective of this work was to investigate how erect milkvetch planting would affect the physical and chemical properties of soil in degraded arable lands. Soil samples at the depths of 0-20 and 20-40 cm were collected from erect milkvetch planting fileds at ages of 0, 1, 2 and 3 yr. Changes in soil bulk density, soil porosity, total N and P, organic matter content, available P, hydrolysable N and available K were measured. The results showed that root biomass and above-ground plant biomass were both significantly increased with plantation age. The significant increase in root nodule biomass was not observed in the first two years. However, it was significantly increased after three years. Root growth of erect milkvetch improved soil structure, and hence, decreased soil bulk density and increased soil porosity. Furthermore, the nitrogen fixation by erect milkvetch and return of erect milkvetch plant to soil increased the soil total N, hydrolysable N and organic matter content of the soil. Low concentrations of P in the soil with erect milkvetch planting could be ascribed to high plant uptakes and possibly to high sequestrations of P in plant biomass. Concentrations of K significantly increased during the first two years of erect milkvetch planting. The high accumulation of K under erect milkvetch cultivation in the first two years could partly be attributed to low plant uptake, and partly to relatively quick recycling within plant-soil systems. Three years after erect milkvetch plantingr, K accumulation at 0-20 cm soil layer was significantly lower than that from non-vegetated field sites, which could be attributed to high plant uptake. These parameters, except for soil bulk density, were all decreased with increasing soil depth. Soil total N, organic matter, porosity and available K in the 20-40 cm layer all showed linear increase trends, and soil bulk density, total P and available P in the depth 0-20 cm layer soil were decreased with increasing planting age. Erect milkvetch establishment could be an effective and applicable measure to improve soil nutrients, and prevent further soil degradation and erosion.     

Effects of subsoiling depth,period interval and combined tillage practice on soil properties and yield in the Huang-Huai-Hai Plain,China

Compaction layers are widely distributed in the Huang-Huai-Hai Plain, China, which restrict root growth and reduce yields. The adoption of subsoiling has been recommended to disrupt compacted soil layers and create a reasonable soil structure for crop development. In this paper, the effects of subsoiling depth(30, 35 and 40 cm), period interval(2 or 3 years) and combined pre-sowing tillage practice(rotary cultivation or ploughing) on soil condition improvement was studied on a tidal soil in the Huang-Huai-Hai Plain. Seven tillage patterns were designed by combining different subsoiling depths, period intervals and pre-sowing. The evaluation indicators for soil condition improvement were as follows: thickness of the plough layer and hard pan, soil bulk density, cone index, soil three-phase R values, alkali nitrogen content, crop yield, and economic benefits. The results showed that subsoiling can significantly improve the soil structure and physical properties. In all subsoiling treatments, the depth of 35 or 40 cm at a 2-year interval was the most significant. The thickness of the plough layer increased from 13.67 cm before the test to 21.54–23.45 cm in 2018. The thickness of the hard pan decreased from 17.68 cm before the test to 12.09–12.76 cm in 2018, a decrease of about 40.07%. However, the subsoiling combined presowing tillage practice, that is, rotary cultivation or ploughing, was not significant for soil structure and physical properties. For all subsoiling treatments, the soil bulk density, cone index and soil three-phase R values of the 15–25 cm soil layer were significantly lower compared to single rotary cultivation. Subsoiling was observed to increase the soil alkaline nitrogen and water contents. The tillage patterns that had subsoiling at the depth of 35–40 cm at a 2-year interval combined with rotary cultivation had the highest alkali nitrogen and water contents, which increased by 31.08–34.23% compared with that of the single rotary cultivation. Subsoiling can significantly increase the yield both of wheat and corn, as well as the economic benefits. The treatment of subsoiling at the depth of 35 cm at an interval of 2 years combined with rotary cultivation had the highest annual yield and economic benefits. For this treatment, the annual yield and economic benefits increased by 14.55 and 62.87% in 2018, respectively. In conclusion, the tillage patterns that involved subsoiling at a depth of 35 cm at a 2-year interval along with rotary cultivation are suitable for the Huang-Huai-Hai Plain.     

Population Dynamics and Survival of Rhizoctonia solaniAG-1 in Field Soil Under Rice-Wheat Rotation

A field under rice-wheat rotation was selected near Chengdu, China, to study the population of Rhizoctonia solani anastomosis group 1 (AG-1), pathogen causing rice sheath blight disease, in natural soil ecosystem. Inocula of the fungus recovered from the field were divided into three types, i.e., sclerotia, free mycelium retained in the soil passed through a 0.355mm sieve, and colonized plant debris which was subdivided into small colonized debris retained between 2.00 and 0.355mm sieves and large colonized debris retained on 2.00mm sieve after wet screening. Quantitative estimation of the three types of inocula in one year indicated that small colonized debris was the dominant inoculum type for most of the time. The population peaked in March and September at 1 210 and 480 colonized debris i00 g^-1 air-dry soil respectively, and fell down in December and August to 0 and 177 colonized debris 100 g^-1 air-dry soil respectively. Free mycelium was only detectable in March, September and October with 1 209, 7.9 and 14.5 μg fresh wt myceliumg^-1 air-dry soil respectively, which corresponded to the two peaks and the second highest level of small debris density in the year. Viable sclerotia and large colonized debris were rare with populations ranging from 0 to 3 for sclerotia and 0 to 14 for large colonized debris 100 g^-1 air-dry soil, but were the main structures to survive over winter. It was expected that soil temperature was the main factor determining population dynamics of R.solani AG-I in natural soil. Optimum temperature for population increasing is predicted to be around 15℃, with a range from i0 to 25℃. Viability tests indicated that 60.9% sclerotia could survive after 265 d being buried in natural sandy loam in field conditions in Beijing, while colonized rice straw debris (0.5 - 1.0 cm long) could not yield the fungus on medium plates after 88 d of being buried under the same conditions.     

Subsoiling and Ridge Tillage Alleviate the High Temperature Stress in Spring Maize in the North China Plain

High temperature stress（HTS） on spring maize（Zea mays L.） during the filling stage is the key factor that limits the yield increase in the North China Plain（NCP）.Subsoiling（SS） and ridge tillage（R） were introduced to enhance the ability of spring maize to resist HTS during the filling stage.The field experiments were conducted during the 2011 and 2012 maize growing seasons at Wuqiao County,Hebei Province,China.Compared with rotary tillage（RT）,the net photosynthetic rate,stomatal conductance,transpiration rate,and chlorophyll relative content（SPAD） of maize leaves was increased by 40.0,42.6,12.8,and 29.7% under SS,and increased by 20.4,20.0,5.4,and 14.2% under R,repectively.However,the treatments reduce the intercellular CO 2 concentration under HTS.The SS and R treatments increased the relative water content（RWC） by 11.9 and 6.2%,and the water use efficiency（WUE） by 24.3 and 14.3%,respectively,compared with RT.The SS treatment increased the root length density and soil moisture in the 0-80 cm soil profile,whereas the R treatment increased the root length density and soil moisture in the 0-40 cm soil profile compared with the RT treatment.Compared with 2011,the number of days with temperatures 33°C was more 2 d and the mean day temperature was higher 0.9°C than that in 2012,whereas the plant yield decreased by 2.5,8.5 and 10.9%,the net photosynthetic rate reduced by 7.5,10.5 and 18.0%,the RWC reduced by 3.9,5.6 and 6.2%,and the WUE at leaf level reduced by 1.8,5.2 and 13.1% in the SS,R and RT treatments,respectively.Both the root length density and the soil moisture also decreased at different levels.The yield,photosynthetic rate,plant water status,root length density,and soil moisture under the SS and R treatments declined less than that under the RT treatment.The results indicated that SS and R can enhance the HTS resistance of spring maize during the filling stage,and led to higher yield by directly improving soil moisture and root growth and indirectly improving plant water status,photosynthesis and grain filling.The study can provide a theoretical basis for improving yield of maize by adjusting soil tillage in the NCP.     

Effects of Soil Water Content on Cotton Root Growth and Distribution Under Mulched Drip Irrigation

The relation between soil water content and the growth of cotton root was studied for the scheme of field water and cotton yield under mulched drip irrigation. Based on the field experiments, three treatments of soil water content were conducted with 90%, 75%θf, and 60%θf （θfis field water capacity）. Cotton roots and root-shoot ratio were studied with digging method, and the soil moisture was observed with TDR （time domain reflector）, and cotton yield was measured. The results indicated that the growth of cotton root accorded with Logistic growth curve in the three treatments, the cotton root grew quickly and its weight was very high under 75%θf because of the suitable soil water condition, while grew slowly and its weight was lower under 90%θf due to water moisture beyond the suitable condition, and the root weight was in between under 60%θf For the three water treatments, the cotton root weight decreased with soil depth, and decreased more significantly in deeper soil layer with the soil moisture increasing. And the ratio of cotton root weight in 0-30 cm soil layer to the total root weight was the highest under 75%θf. The cotton root system was distributed mainly in the soil of narrow row and wide row mulched with plastic film, and little in the soil outside plastic film. The weight of cotton root was the highest in the soil of narrow row or wide row mulched with plastic film under 75%θf. Root-shoot ratio decreased with the soil moisture increasing. The soil water content affected cotton yields, and cotton yield was the highest under 75%θf. The higher soil moisture level is unfavorable to the growth of cotton root system and yield of cotton under mulched drip irrigation.     

The inf luence of soil drying- and tillage-induced penetration resistance on maize root growth in a clayey soil

Soil drying may induce a number of stresses on crops. This paper investigated maize(Zea mays L.) root growth as affected by drought and soil penetration resistance(PR), which was caused by soil drying and tillage in a clayey red soil. Compared with conventional tillage(C) and deep tillage(D), soil compaction(P) and no-till(N) significantly increased soil PR in the 0–15 cm layer. The PR increased dramatically as the soil drying increased, particularly in soil with a high bulk density. Increased soil PR reduced the maize root mass density distribution not only in the vertical profile(0–20 cm) but also in the horizontal layer at the same distance(0–5, 5–10, 10–15 cm) from the maize plant. With an increase in soil PR in pots, the maize root length, root surface area and root volume significantly decreased. Specifically, the maize root length declined exponentially from 309 to 64 cm per plant with an increase in soil PR from 491 to 3 370 k Pa; the roots almost stopped elongating when the soil PR was larger than 2 200 k Pa. It appeared that fine roots(2.5 mm in diameter) thickened when the soil PR increased, resulting in a larger average root diameter. The average root diameter increased linearly with soil PR, regardless of soil irrigation or drought. The results suggest that differences in soil PR caused by soil drying is most likely responsible for inconsistent root responses to water stress in different soils.     

Effects of sediment load on the abrasion of soil aggregate and hydraulic parameters in experimental overland flow

The breakdown of soil aggregates under rainfall and their abrasion in overland flow are important processes in water erosion due to the production of more fine and transportable particles and, the subsequent significant effect on the erosion intensity. Currently, little is known about the effects of sediment load on the soil aggregate abrasion and the relationship of this abrasion with some related hydraulic parameters. Here, the potential effects of sediment load on soil aggregate abrasion and hydraulic parameters in overland flow were investigated through a series of experiments in a 3.8-m-long hydraulic flume at the slope gradients of 8.7 and 26.8%, unit flow discharges from 2×10~(–3) to 6×10~(–3) m~2 s~(-1), and the sediment concentration from 0 to 110 kg m~(–3). All the aggregates from Ultisols developed Quaternary red clay, Central China. The results indicated that discharge had the most significant(P0.01) effect on the aggregates abrasion with the contributions of 58.76 and 60.34%, followed by sediment feed rate, with contributions of 39.66 and 34.12% at the slope gradients of 8.7 and 26.8%, respectively. The abrasion degree of aggregates was found to increase as a power function of the sediment concentration. Meanwhile, the flow depth, friction factor, and shear stress increased as a power function along with the increase of sediment concentration at different slope gradients and discharges. Reynolds number was obviously affected by sediment concentration and it decreased as sediment concentration increased. The ratio of the residual weight to the initial weight of soil aggregates(Wr/Wi) was found to increase as the linear function with an increasing flow depth(P=0.008) or Reynolds number(P=0.002) in the sediment-laden flow. The Wr/Wi values followed a power function decrease with increasing friction factor or shear stress in the sediment-laden flow, indicating that friction factor is the best hydraulic parameter for prediction of soil aggregate abrasion under different sediment load conditions. The information regarding the soil aggregate abrasion under various sediment load conditions can facilitate soil process-based erosion modeling.     

重粉质壤土泥浆特性动态检测

[目的]为用含粘粒量高的土修建水坠坝提供基础资料和理论指导。[方法]以陕西白水县西武村附近大沟流域的土作为试验对象,用等高等直径的PVC管样桶组建测试模型,对2种灌浆速度(15和25 cm/d)下灌浆体的沉降量、抗剪强度、湿密度、下渗量等指标进行动态测定。[结果]不同灌浆速度下,灌浆过程中灌浆体各指标的总体变化趋势相同。对于同一高度的灌浆体,其沉陷变形、抗剪强度、湿密度均表现为灌浆速度大则相应的值大。灌浆5~6 d以后,以25 cm/d速度灌浆的日排水量小于以15 cm/d速度灌浆的日排水量。[结论]灌浆速度加大可缩短达到相同沉陷变形、抗剪强度和湿密度的时间,可明显增加灌浆初期排水量,但随灌浆时间的累积,下层灌浆体接近不透水层而不利于灌浆后期的排水。     

菌糠改良保护地土壤容重退化效果的研究

[目的]探讨食用菌菌糠做底肥对保护地土壤容重的改良效果。[方法]以平菇菌糠为底肥,用环刀法测定种植西红柿的保护地土壤容重。[结果]随着施用菌糠量的增加,土壤容重由1.38g/cm^3减小到1.14g/cm^3,处理间具有0.01水平显著差异。[结论]菌糠改良保护地土壤容重的效果良好,并且西红柿的产量和品质都得到明显的提高。     

香根草根系固土拉力的原位测定

 应用锚杆拉力计和项目组自行设计改进的剪切箱,原位测定了不同深度（10cm,20cm）分蘖期香根草根系固土、单根拉力。结果表明,在给香根草施加载荷初期,根系都会发生弹性形变,荷载与位移都按比例增加,呈现一定的线性关系。当载荷超过根系抗拉极限后,随着拉力的继续增加,根系发生塑性形变,载荷与位移关系逐渐偏离直线,反映出非线性弹性特征,测定的土体样方与土体分离。但与裸土样方相比,在施加同样载荷的情况下,有根样方位移明显要小于无根样方,说明香根草具有一定的固土能力,并且根系入土越深,植物固土能力越强。     

风沙土机械组成、容重和孔隙度对采煤塌陷的响应

通过测定和计算毛乌素沙地东南缘补连塔煤矿塌陷区和非塌陷区风沙土机械组成、容重、孔隙度,应用空间对比法研究采煤塌陷对风沙土物理性质的影响。试验结果表明:与非塌陷区相比,塌陷区物理性粘粒含量明显减少(P<0.05),尤其地表10 cm土层最为显著;与非塌陷区相比,塌陷区风沙土容重、孔隙度在不同坡位有明显差异,其中沙丘顶部和中部容重和孔隙度变化不明显(P=0.1),而沙丘底部和丘间低地容重明显减小,孔隙度明显增大(P<0.05);从垂直剖面上看,0 cm~40 cm层容重和孔隙度无明显变化(P=0.1),40 cm~100 cm层容重明显变小,孔隙度明显增大(P<0.05);裂缝密度对风沙土容重、孔隙度的影响不明显;在采空区边界,陷落幅度对风沙土容重影响较小,在采空区内部随着陷落幅度的增大,低位陷落体容重有随机减小趋势。     

厚黄土薄基岩型采煤沉陷区农田土壤物理性状空间变异初探

以山西潞安集团司马煤矿为例,针对厚黄土薄基岩型煤层地质,对沉陷破坏农田的不同沉陷深度下土壤物理性状空间变异进行了研究。结果表明:开采沉陷加速沉陷区农田土壤的侵蚀和水土流失,从而显著影响农田土壤的物理性状,受其影响最大的是0～20 cm土层,其次是20～40 cm土层;沉陷农田随着下沉深度的加深,土壤含水量呈增加趋势;土壤容重从上坡开始随下沉深度的加深而增加,至下沉深度7 m时达最大值;土壤孔隙度的变化规律同土壤容重相反;在沉陷2年的沉陷区农田中,不同土壤物理性状受开采沉陷影响的程度不一样,受其影响最大的是土壤容重,其次是土壤孔隙度和土壤含水量。     

盐角草对滴灌条件下积盐范围内盐分的影响

[目的]确定湿润峰、积盐范围及盐角草吸盐能力,控制积盐范围内盐分。[方法]以pH 7.9的水作为灌溉水源,在不同土壤初始含水率、土壤容重及滴头流量的条件下研究土壤湿润体的变化过程。[结果]盐角草吸走部分Na＋、Cl-抑制盐分,积盐范围内土深20cm处的总含盐量降低了0.12 g/kg。[结论]该研究可以为有效地控制滴灌条件下湿润锋边缘积累盐分提供依据。     

模拟农业机械对土壤压实的试验研究

[目的]进行模拟农业机械对土壤压实的实验,为研究农业机械对土壤造成的压实破坏提供理论依据。[方法]重塑含水率(级差为3%)和体积密度(级差为0.2 g/cm3)不同的水稻土和黄棕壤,利用土壤固结仪对其进行模拟压实,分析压实对土壤容重、饱和持水率和应力传递系数的影响。[结果]随着含水率的增加,压实对土壤的影响逐渐加重,且当土壤含水率在16%~22%时压实对土壤产生的破坏较为严重。土壤抗压实能力随体积密度的增加而增加。相同含水率和体积密度土壤应力传递系数不变,即传递至土壤底层应力σz与土壤表面施加力σ0呈相对稳定的线性关系。[结论]机械压实会使土壤容重增加,饱和持水率降低。随着土壤含水率的减少和体积密度的增加,压实对土壤的影响减弱。土壤应力传递系数与土壤类型、含水率、体积密度等有关。对于给定状态的土壤,其土壤应力传递系数不变。     

不同水土保持措施对红壤坡耕地土壤物理性质的影响

【目的】针对红壤坡耕地土壤结构差、水土流失严重等问题,研究不同水土保持措施对土壤容重、孔隙度等土壤物理性质的影响,为实现红壤坡耕地的持续、高效利用提供参考。【方法】以等高花生常规耕作为对照(CK),探析表施聚丙烯酰胺(PAM)、香根草篱和PAM+香根草篱等3种水土保持措施对土壤容重、孔隙度、持水量的影响,综合评价不同措施对土壤物理性质的改良效果。【结果】不同水土保持措施处理下0~20 cm土层土壤容重差异显著(P<0.05),3种水土保持措施主要对红壤坡耕地0~20 cm土壤容重改善效果明显;不同处理下0~40 cm土层土壤孔隙度和持水量差异不显著(P>0.05),不同水土保持措施对0~10 cm土层土壤孔隙度和持水量的提升效果较好。土壤容重与其他土壤物理指标呈负相关,且作为主成分评价不同水土保持措施对土壤物理性质的改良效果的贡献率较高(76.517%)。【结论】土壤容重是评价不同水土保持措施对土壤物理性质改良效果的重要因子,影响着土壤孔隙度和持水量等物理性质;不同水土保持措施对0~10 cm土层土壤物理性质的综合改良效果较好,且以表施PAM+香根草篱效果最佳,是值得推广应用的红壤坡耕地水土保持措施。