两种代表性蚯蚓对设施菜地土壤微生物群落结构及理化性质的影响

不同生态型蚯蚓的取食偏好和生境有所差异,因此蚯蚓的生态型差异可能关乎其对土壤性质的不同影响;有关不同生态型蚯蚓对土壤性质尤其是微生物学性质影响的研究有助于了解蚯蚓生态功能的作用机制。在野外调控试验的第4年采集土壤,研究了牛粪混施和表施处理下内层种威廉腔环蚓(Metaphire guillelmi)和表层种赤子爱胜蚓(Eisenia foetida)对设施菜地土壤微生物群落结构和主要理化性质的影响。结果表明,土壤微生物群落结构同时受到蚯蚓种类和牛粪施用方式的影响。牛粪表施时,两种蚯蚓均显著降低了菌根真菌、真菌生物量和原生动物生物量(P0.05);牛粪混施时,不同蚯蚓的影响有所差异,威廉腔环蚓明显增加了菌根真菌、真菌生物量和放线菌生物量,而赤子爱胜蚓的作用不明显。此外,两种蚯蚓均提高了土壤孔隙度、团聚体稳定性和土壤p H、矿质氮以及微生物生物量碳氮水平,但提高幅度取决于蚯蚓种类和牛粪施用方式。冗余分析表明蚯蚓影响下土壤微生物群落结构的变化与团聚体稳定性、p H、速效磷、矿质氮呈正相关,而与土壤容重呈负相关。     

Does biochar influence soil physical properties and soil water availability?

Aims

This study aims to (i) determine the effects of incorporating 47 Mg ha^?1 acacia green waste biochar on soil physical properties and water relations, and (ii) to explore the different mechanisms by which biochar influences soil porosity.

Methods

The pore size distribution of the biochar was determined by scanning electron microscope and mercury porosimetry. Soil physical properties and water relations were determined by in situ tension infiltrometers, desorption and evaporative flux on intact cores, pressure chamber analysis at ?1,500 kPa, and wet aggregate sieving.

Results

Thirty months after incorporation, biochar application had no significant effect on soil moisture content, drainable porosity between –1.0 and ?10 kPa, field capacity, plant available water capacity, the van Genuchten soil water retention parameters, aggregate stability, nor the permanent wilting point. However, the biochar-amended soil had significantly higher near-saturated hydraulic conductivity, soil water content at ?0.1 kPa, and significantly lower bulk density than the unamended control. Differences were attributed to the formation of large macropores (>1,200 μm) resulting from greater earthworm burrowing in the biochar-amended soil.

Conclusion

We found no evidence to suggest application of biochar influenced soil porosity by either direct pore contribution, creation of accommodation pores, or improved aggregate stability.     

Predicting exotic earthworm distribution in the northern Great Lakes region

Identifying influences of earthworm invasion and distribution in the northern Great Lakes is an important step in predicting the potential extent and impact of earthworms across the region. The occurrence of earthworm signs, indicating presence in general, and middens, indicating presence of Lumbricus terrestris exclusively, in the Huron Mountains located in the Upper Peninsula of Michigan were modeled using generalized linear models and stepwise regression to identify important environmental variables. Models were then applied to earthworm occurrence data from Seney National Wildlife Refuge, also located in the Upper Peninsula of Michigan to validate results. Occurrence of earthworm signs was associated with high soil pH, high basal area of earthworm preferred overstory species, and north facing aspects. Middens of L. terrestris were associated with high soil pH, high basal area of preferred species, and close proximity to roads. The resulting model for L. terrestris was incorporated into a geographic information system (GIS) to map the expected distribution, both current and potential, across the study area. Results indicate that L. terrestris has not yet fully saturated its potential habitat, as it is currently found close to roads and has yet to establish in most interior forests sampled. Comparing field measured data to GIS layers revealed limitations in the precision of publicly available spatial data layers that should be addressed in future attempts to predict the extent of earthworm invasion across the larger Great Lakes region. However, within the Huron Mountains, it is predicted that the distribution of L. terrestris will cover, at minimum, 41 % of the area.     

渭北旱作麦田长期保护性耕作土壤肥力特征综合评价

以渭北旱作麦田10年长期定位试验4种土壤物理指标和7种化学指标组成的土壤肥力性质为评价指标,研究长期实施6种保护性耕作处理后11种土壤指标的累积效应,并运用主成分分析对不同耕作处理下土壤肥力的累积效果进行综合评分,以期为渭北旱塬土壤可持续利用和管理提供科学依据.结果表明: 与传统连续翻耕(CT/CT)比较,免耕与深松轮耕(NT/ST)、深松与翻耕轮耕(ST/CT)、翻耕与免耕轮耕(CT/NT)处理土壤容重分别降低了6.6%、5.9%、6.6%,连续免耕(NT/NT)与连续翻耕差异不明显.>0.25 mm力稳性团聚体含量以NT/NT最高,水稳性团聚体含量以NT/ST最高.与传统翻耕相比,5种耕作处理力稳性团聚体增加了1.7%～10.1%,土壤有机质增加了0.6%～11.2%,氮、磷、钾含量也均有提高.通过主成分分析将11种土壤指标分为两个主成分综合表征土壤质量,第1主成分的贡献率为75.5%,在其上有较高载荷的指标为土壤有机质、水稳性团聚体、全氮、全磷、全钾、碱解氮、速效磷、速效钾含量,容重、孔隙度,第2主成分的贡献率为13.2%,力稳性团聚体在其上有较高载荷,两者共解释了88.6%的原变量.长期不同耕作效果逐渐累加形成的土壤肥力水平依次表现为:NT/ST>ST/CT>CT/NT>NT/NT>ST/ST>CT/CT,NT/ST处理形成了一个相对平衡和较高肥力质量的土壤状况,为渭北旱作麦田最适宜的轮耕模式.     

夏闲期轮耕对小麦田土壤水分及产量的影响

2007-2010年在宁南旱区研究了夏闲期免耕/深松/免耕(T1)、深松/免耕/深松(T2)、连年翻耕(CT)3种耕作方式对麦田土壤水分及产量的影响.结果表明:经过3年夏闲期T1和T2处理后,农田土壤蓄水效率平均分别较连年翻耕处理提高15.2％和26.5％;T1和T2处理的降水潜在利用率较高,分别达到37.8％和38.5％,降水生产效率平均分别较连年翻耕处理提高9.9％和10.7％.夏闲期轮耕能显著降低休闲期的土壤无效蒸发,有效保蓄小麦生长期的土壤水分.在冬小麦生长前期,T1和T2处理0～200 cm土层土壤水分平均分别较连年翻耕处理增加6.8％和9.4％;在拔节-抽穗-灌浆期,与连年翻耕处理相比,两处理可显著提高0 ～ 200 cm土层土壤蓄水量,对作物产量的贡献率较高.不同轮耕模式在增加作物耗水量的同时也提高了作物产量及水分利用效率,与CT处理相比,3年T1和T2处理作物耗水量平均分别提高5.2％和6.1％,产量分别增加9.9％和10.6％,作物水分生产效率分别提高4.5％和4.3％.相关分析表明,在干旱缺水的宁南地区,冬小麦播种期、拔节-抽穗-灌浆期的土壤蓄水量可显著影响产量,尤其抽穗期的土壤蓄水量对产量的影响更大.     

不同还田方式对砂质潮土理化性质及微生物的影响

为探索不同物料还田方式对中低产田砂质潮土的改良效果,在黄淮海平原麦玉轮作区典型砂质潮土上进行了连续6季的田间小区试验,设置全量秸秆翻耕还田(TS),秸秆等碳量的生物炭(TB)及半量秸秆半量生物炭配合翻耕还田(TSB),全量秸秆免耕覆盖还田(NTS)和半量秸秆半量生物炭配合免耕覆盖还田(NTSB),共5种还田方式。结果表明,与常规秸秆翻耕还田(TS)相比,生物炭翻耕还田(TB)显著降低土壤容重,增加玉米各个生育期土壤水分和p H值,有机质含量提升了16.4%,但TB处理的土壤大团聚体降低了21.2%和微生物数量降低了16.1%;翻耕秸秆配合生物炭还田(TSB)除了显著降低了大团聚体数量,对其余理化及微生物指标的影响均不显著;免耕模式下的秸秆还田(NTS)和秸秆生物炭配施(NTSB)分别在玉米生长的喇叭口期和收获期显著增加了土壤水分含量、耕层土壤的微生物数量和有效降低砂质潮土分形维数,对容重和有机质含量有一定的改善,其中NTSB有机质含量提升了14.9%和微生物数量增加了53.7%,对砂质潮土改良效果更好。总体来说,短期内用等碳量的生物炭替代秸秆翻耕还田更多的表现为物理的掺混效应,虽能有效提升土壤有机质含量,但不能有效改善砂质潮土的物理结构及生物性质,一半秸秆用生物炭替代还田对该类土壤的理化及微生物指标的改良效果也不显著,而免耕条件下秸秆配合生物碳还田效果最佳,可为砂质潮土的改良提供新的途径和理论依据。     

Short-term effects of biological and physical forces on aggregate formation in soils with different clay mineralogy

The mechanisms resulting in the binding of primary soil particles into stable aggregates vary with soil parent material, climate, vegetation, and management practices. In this study, we investigated short-term effects of: (i) nutrient addition (Hoagland's solution), (ii) organic carbon (OC) input (wheat residue), (iii) drying and wetting action, and (iv) root growth, with or without dry–wet cycles, on aggregate formation and stabilization in three soils differing in weathering status and clay mineralogy. These soils included a young, slightly weathered temperate soil dominated by 2:1 (illite and chlorite) clay minerals; a moderately weathered soil with mixed [2:1 (vermiculite) and 1:1 (kaolinite)] clay mineralogy and oxides; and a highly weathered tropical soil dominated by 1:1 (kaolinite) clay minerals and oxides. Air-dried soil was dry sieved through a 250 m sieve to break up all macroaggregates and 100 g-subsamples were brought to field capacity and incubated for 42 days. After 14 and 42 days, aggregate stability was measured on field moist and air-dried soil, to determine unstable and stable aggregation respectively. In control treatments (i.e., without nutrient or organic matter addition, without roots and at constant moisture), the formation of unstable and stable macroaggregates (> 250 m) increased in the order: 2:1 clay soil < mixed clay soil < 1:1 clay soil. After 42 days of incubation, nutrient addition significantly increased both unstable and stable macroaggregates in the 2:1 and 1:1 clay soils. In all soils, additional OC input increased both unstable and stable macroaggregate formation. The increase in macroaggregation with OC input was highest for the mixed clay soil and lowest for the 1:1 clay soil. In general, drying and wetting cycles had a positive effect on the formation of macroaggregates. Root growth caused a decrease in unstable macroaggregates in all soils. Larger amounts of macroaggregates were found in the mixed clay and oxides soil when plants were grown under 50% compared to 100% field capacity conditions. We concluded that soils dominated by variable charge clay minerals (1:1 clays and oxides) have higher potential to form stable aggregates when OC concentrations are low. With additional OC inputs, the greatest response in stable macroaggregate formation occurred in soils with mixed mineralogy, which is probably a result of different binding mechanisms occurring: i.e., electrostatic bindings between 2:1 clays, 1:1 clays and oxides (i.e. mineral-mineral bindings), in addition to OM functioning as a binding agent between 2:1 and 1:1 clays.     

The effects of stubble retention and tillage practices on surface soil structure and hydraulic conductivity of a loess soil

The current cropping system of excessive tillage and stubble removal in the northwestern Loess Plateau of China is clearly unsustainable. A better understanding of tillage and stubble management on surface soil structure is vital for the development of effective soil conservation practices in the long term. Changes in surface soil structure and hydraulic properties were measured after 4 years of stubble management (stubble retained vs. stubble removed) under contrasting tillage practices (no-tillage vs. conventional tillage) in a silt loam soil (Los Orthic Entisol) in Dingxi, Gansu, the northwestern Loess Plateau, China. Our results indicated that after 4 years small but significant changes in soil properties were observed amongst the different tillage and stubble treatments. Surface soil (0–5 cm) under no-tillage with stubble retention had the highest water stability of macroaggregates (>250 μm), soil organic carbon (SOC) and saturated hydraulic conductivity. Significant correlation was found between water stable macro-aggregates and soil organic carbon content, indicating the importance of the latter on soil structural stability. The improvement in soil structure and stability was confirmed by higher soil hydraulic conductivity measurements. Consistently higher K_sat was detected in the no tillage with stubble retained soil compared to other treatments. Therefore, no-tillage with stubble retention practice is an effective management technique for improving physical quality of this fragile soil in the long term.     

不同耕作方式对内蒙古旱作农田土壤侵蚀的影响

研究黄河流域内蒙古黄土高原丘陵区农田土壤侵蚀状况,对本区域生态农业建设具有重要的意义。试验于2006年在内蒙古呼和浩特市清水河县进行,设免耕(NT)、免耕覆盖(NS)和传统耕作(CT)3种耕作处理方式,种植作物为胡麻和燕麦,观测了全年降雨量和地表水径流量及土壤流失量。结果表明:免耕覆盖及免耕能显著减少降雨对土壤的侵蚀,与传统耕作相比,免耕覆盖处理的燕麦地地表水径流量和土壤的流失量分别减少21.9%和88.3%;3种耕作方式的土壤侵蚀量均受到坡度的影响,并随着坡度的增大而增大,相同环境条件下,不同作物存在一定差异;通过对3种耕作方式下,胡麻和燕麦田土壤侵蚀量与降雨量的关系符合幂函数,且拟合优度良好,均>0.9。     

Nitrogen and harvest effects on soil properties under rainfed switchgrass and no‐till corn over 9 years: implications for soil quality

Nitrogen fertilizer and harvest management will alter soils under bioenergy crop production and the long‐term effects of harvest timing and residue removal remain relatively unknown. Compared to no‐tilled corn (NT‐C, Zea mays L.), switchgrass (Panicum virgatum L.) is predicted to improve soil properties [i.e. soil organic C (SOC), soil microbial biomass (SMB‐C), and soil aggregation] due to its perennial nature and deep‐rooted growth form, but few explicit field comparisons exist. We assessed soil properties over 9 years for a rainfed study of N fertilizer rate (0, 60, 120, and 180 kg N ha^?1) and harvest management on switchgrass (harvested in August and postfrost) and NT‐C (with and without 50% stover removal) in eastern NE. We measured SOC, aggregate stability, SMB‐C, bulk density (BD), pH, P and K in the top 0–30 cm. Both NT‐C and switchgrass increased SMB‐C, SOC content, and aggregate stability over the 9 years, reflecting improvement from previous conventional management. However, the soils under switchgrass had double the percent aggregate stability, 1.3 times more microbial biomass, and a 5–8% decrease in bulk density in the 0–5 and 5–10 cm depths compared to NT‐C. After 9 years, cumulative decrease in available P was significantly greater beneath NT‐C (?24.0 kg P ha^?1) compared to switchgrass (?5.4 kg P ha^?1). When all measured soil parameters were included in the Soil Management Assessment Framework (SMAF), switchgrass improved soil quality index over time (ΔSQI) in all depths. NT‐C without residue removal did not affect ΔSQI, but 50% residue removal decreased ΔSQI (0–30 cm) due to reduced aggregate stability and SMB‐C. Even with best‐management practices such as NT, corn stover removal will have to be carefully managed to prevent soil degradation. Long‐term N and harvest management studies that include biological, chemical, and physical soil measurements are necessary to accurately assess bioenergy impacts on soils.     

冻融交替对黑土团聚体稳定性的影响

应用Le Bissonnais法分析冻融循环(0、1、3、5和9)对3～5 mm黑龙江省黑土团聚体稳定性的影响,采用蜡封法分析黑土孔隙度的变化.结果表明: 不同粒径团聚体含量随冻融循环次数增加均呈波动状态,团聚体含量变化系数随冻融循环次数的增加逐渐趋于稳定;快速湿润、慢速湿润、预湿润震荡3种处理土壤中>0.25 mm团聚体含量有明显差异;孔隙度随冻融循环次数的增加而增大,变化范围在32.4%～41.4%.随冻融次数的增加,不同破碎方式下团聚体含量变化程度较低,团聚体平均重量直径与孔隙度呈负相关,表明冻融条件下孔隙度是影响团聚体稳定性的重要因素.     

High abundance of introduced plants on ancient Native American middens

Past land uses by humans can have long-term effects on natural communities. To test the hypothesis that past land use can alter patterns of biological invasion for extended times, we predicted that middens abandoned by Native Americans over a century ago would have high abundances of introduced plants. We measured cover of vascular species and soil characteristics on and off the eight remaining middens in grasslands along 20 km of the northern coast of California. Relative cover of introduced plants was about 20% higher on than off middens, and cover of introduced annuals was about 110% higher. Concentration of inorganic N in the upper soil was twice as high on as off middens and explained about 40% of the variation in cover of introduced annuals. Abundance of shells on middens was correlated with inorganic N, suggesting that present invasion was linked to intensity of past land use. Results confirm that ancient land use by Native Americans is associated with present-day invasion by introduced plants and suggest that persistent elevation of soil N is partly responsible. Land use that elevates nutrient levels may promote invasion far into the future.     

Mechanisms linking plant community properties to soil aggregate stability in an experimental grassland plant diversity gradient

Background and aims

Soil aggregate stability depends on plant community properties, such as functional group composition, diversity and biomass production. However, little is known about the relative importance of these drivers and the role of soil organisms in mediating plant community effects.

Methods

We studied soil aggregate stability in an experimental grassland plant diversity gradient and considered several explanatory variables to mechanistically explain effects of plant diversity and plant functional group composition. Three soil aggregate stability measures (slaking, mechanical breakdown and microcracking) were considered in path analyses.

Results

Soil aggregate stability increased significantly from monocultures to plant species mixtures and in the presence of grasses, while it decreased in the presence of legumes, though effects differed somewhat between soil aggregate stability measures. Using path analysis plant community effects could be explained by variations in root biomass, soil microbial biomass, soil organic carbon concentrations (all positive relationships), and earthworm biomass (negative relationship with mechanical breakdown).

Conclusions

The present study identified important drivers of plant community effects on soil aggregate stability. The effects of root biomass, soil microbial biomass, and soil organic carbon concentrations were largely consistent across plant diversity levels suggesting that the mechanisms identified are of general relevance.     

免耕施肥对稻田甲烷与氧化亚氮排放及其温室效应的影响

2008年采用静态箱-气相色谱法对鄂东南免耕不施肥(NT₀)、翻耕不施肥(CT₀)、免耕施肥(NTC)和翻耕施肥(CTC) 4种处理下稻田CH₄和N₂O的排放进行测定.结果表明：各处理CH₄排放均呈先升高后降低的季节性规律,而N₂O排放的季节性规律不明显;施肥显著提高了稻田CH₄和N₂O的排放.与翻耕不施肥相比,免耕不施肥显著提高了CH₄的排放量,并显著降低了N₂O的排放量;与翻耕施肥相比,免耕施肥仅略降低了CH₄的排放量和略提高了N₂O的排放量.对稻田CH₄和N₂O两种气体的综合温室效应分析表明,与翻耕不施肥相比,免耕不施肥的综合温室效应提高了25.9%,与翻耕施肥相比,免耕施肥的综合温室效应降低了10.1%.因此,合理的肥料运筹和稻田免耕技术可降低两种气体的综合温室效应.     

长期免耕不同秸秆覆盖量对玉米产量及其稳定性的影响

阐明长期免耕不同秸秆覆盖量下玉米产量变化趋势及其稳定性差异,可为建立和评价长期保护性耕作模式、促进粮食持续生产提供理论支撑.本研究基于我国东北黑土区长期保护性耕作定位试验(始于2007年),以传统垄作(RT)为对照,分析了免耕无秸秆覆盖(NT0)、免耕33％秸秆覆盖(NT33)、免耕67％秸秆覆盖(NT67)和免耕10...     

稻田实行保护性耕作对水稻产量、土壤理化及生物学性状的影响

在江西双季稻田进行长期田间定位试验,分析了多年保护性耕作对水稻产量、土壤理化性状及生物学性状的影响。连续8a稻田保护性耕作处理的平均产量高于传统耕作4.46%—8.79%,各处理的有效穗数、每穗粒数和结实率均高于对照,而各处理间穗长和千粒重差异不显著。实行稻田保护性耕作处理的土壤容重低于传统耕作3.6%—5.6%,而总孔隙度和毛管孔隙度分别高出传统耕作1.6%—17.4%、2.4%—16.7%。与传统耕作相比,连续8a保护性耕作显著提高了土壤有机质(2.9%—10.0%)、有效磷(4.8%—31.6%)、速效钾(9.7%—25.7%)。在2005年免耕+插秧的土壤真菌数量最多,显著高于对照处理51.6%,免耕+抛秧在2008年达到最大,显著高于对照处理54.1%。2012年免耕+抛秧、免耕+插秧显著高于对照126.1%、121.1%;另外,各处理间过氧化氢酶、脲酶活性均差异不显著。8a间土壤转化酶活性变化范围在0.292—0.451 mg/g之间,其中2005—2007、2012年均是免耕+抛秧达到最大,与对照相比,增加范围为72.7%—137.7%,且差异显著(P0.05)。因此,实行稻田保护性耕作是适合江南丘陵区双季稻区农业可持续发展的有效模式之一,其中免耕+抛秧和免耕+插秧两种方式效果最为显著。     

不同耕作方法对水稻生长和土壤生态的影响

1998－1999年在华南双季稻田研究了不同耕作方法水稻生长和土壤生态的影响,结果表明,在抛秧条件下,免耗水稻分蘖数,有效穗数和实粒数减少,水稻产量比传统耕降低13．4％,经济效益减少10．9％,免耕土壤容重和硬度增大,癖孔隙度,非毛管孔隙度和有效P,K降低,放线菌和真菌数量减少,而土壤细菌数量增加,酶活性增强,轻耕和传统耕的土壤物理化学性质,微生物数量和酶活性相似,但轻耕水稻有效穗数和千粒重较高,水稻产量比传统耕增加2．1％,轻耕降低了耕作成本,经济效益比传统耕作提高11．0％。     

不同耕作方式对旱作冬小麦旗叶衰老和籽粒产量的影响

在旱作条件下研究了一次深翻、免耕、深松和传统耕作4种耕作方式对冬小麦花后旗叶衰老、小麦籽粒产量及土壤水分和养分状况的影响.结果表明：免耕和深松提高了小麦旗叶SOD和POD活性及可溶性蛋白和叶绿素含量,降低了MDA和O₂^-·含量,延缓了小麦叶片的衰老进程;同时,免耕、深松在开花期和灌浆期0～40 cm土层土壤水分含量分别比传统耕作提高了4.13％、6.23％和5.50％、9.27％,土壤碱解氮、速效磷和速效钾含量均显著高于传统耕作.一次深翻0～40 cm土层土壤水分含量低于传统耕作,土壤养分含量高于传统耕作,但两处理间差异不显著.与传统耕作相比,免耕和深松花后干物质生产量分别提高4.34％和4.76％,花后干物质转运率分别提高15.56％和13.51％,产量分别提高10.22％和9.26%.免耕和深松为冬小麦花后生长发育提供了良好的环境,延缓了小麦叶片衰老,促进了花后干物质积累及干物质向籽粒的转运,从而使籽粒产量显著提高,是旱作麦区适宜的耕作方式.     

Whey utilization in furrow irrigation: effects on aggregate stability and erosion

Improving soil structure often reduces furrow erosion and maintains adequate infiltration. Cottage cheese whey, the liquid byproduct from cottage cheese manufacture, was utilized to stabilize soil aggregates and reduce sediment losses from furrow irrigation. We applied either 2.4 or 1.9L of whey per meter of furrow (3.15 or 2.49Lm(-2), respectively) by gravity flow without incorporation to two fields of Portneuf silt loam (Durinodic Xeric Haplocalcid) near Kimberly, ID. Furrows were irrigated with water beginning four days later. We measured sediment losses with furrow flumes during each irrigation and measured aggregate stability by wet sieving about 10 days after the last irrigation. Overall, whey significantly increased aggregate stability 25% at the 0-15mm depth and 14% at 15-30mm, compared to controls. On average, whey reduced sediment losses by 75% from furrows sloped at 2.4%. Whey increased the aggregate stability of structurally degraded calcareous soil in irrigation furrows.     

不同土地利用方式对黄河三角洲土壤物理特性的影响

黄河三角洲是我国成土最快的河口三角洲之一,探索其土地利用过程中不同土地利用方式对土壤物理性质的影响,对该区土壤肥力保持和土地资源的持续利用具有重要意义。选择黄河三角洲棉田、麦田、苇地、碱蓬地和裸地等5种不同的土地利用方式,通过野外调查与室内分析,研究不同土地利用方式下土壤主要物理特性的变异特征及影响因素。结果显示,与裸地土壤相比,有植被土地利用方式土壤容重降低,土壤孔隙度、团聚体水稳性、饱和含水量与毛管含水量也有相应的提高;土壤有机碳和速效氮、有效磷含量均有显著增加,土壤总盐分含量呈显著降低趋势。在所研究土壤中,土壤物理性质依麦田-棉田-苇地-碱蓬地-裸地的次序从最佳向最差过渡。逐步回归分析和相关分析表明土壤容重、团聚体平均重量直径和毛管孔隙度是土壤毛管含水量的主要影响因子,团聚体水稳性主要由大于0.25 mm水稳性团聚体含量和毛管孔隙度决定,土壤总盐分含量影响土壤饱和导水率;大于0.25 mm水稳性团聚体含量分别与土壤有机碳含量(r=0.8323)、速效氮含量(r=0.7558)和有效磷含量(r=0.9049)具有正相关关系。因此,黄河三角洲地区土地利用应以增加有机质的投入,提高土壤水稳性团聚体形成为基础,促进土壤良好结构形成。这些结果为该区土壤肥力提高和土壤资源可持续利用提供参考依据。