气候和土壤质地对土壤有机碳影响的区域差异研究

The agricultural soil carbon pool plays an important role in mitigating greenhouse gas emission ana unaerstanamg the son orgamc carbon-climate-soil texture relationship is of great significance for estimating cropland soil carbon pool responses to climate change. Using data from 900 soil profiles, obtained from the Second National Soil Survey of China, we investigated the soil organic carbon （SOC） depth distribution in relation to climate and soil texture under various climate regimes of the cold northeast region （NER） and the warmer Huang-Huai-Hai region （HHHR） of China. The results demonstrated that the SOC content was higher in NER than in HHHR. For both regions, the SOC content at all soil depths had significant negative relationships with mean annual temperature （MAT）, but was related to mean annual precipitation （MAP） just at the surface 0-20 cm. The climate effect on SOC content was more pronounced in NER than in HHHR. Regional differences in the effect of soil texture on SOC content were not found. However, the dominant texture factors were different. The effect of sand content on SOC was more pronounced than that of clay content in NER. Conversely, the effect of clay on SOC was more pronounced than sand in HHHR. Climate and soil texture jointly explained the greatest SOC variability of 49.0% （0-20 cm） and 33.5% （20-30 cm） in NER and HHHR, respectively. Moreover, regional differences occurred in the importance of climate vs. soil texture in explaining SOC variability. In NER, the SOC content of the shallow layers （0-30 cm） was mainly determined by climate factor, specifically MAT, but the SOC content of the deeper soil layers （30-100 cm） was more affected by texture factor, specifically sand content. In HHHR, all the SOC variability in all soil layers was predominantly best explained by clay content. Therefore, when temperature was colder, the climate effect became stronger and this trend was restricted by soil depth. The regional differences and soil depth influence underscored the importance of explicitly considering them in modeling long-term soil responses to climate change and predicting potential soil carbon sequestration.     

美国8种土壤的活性腐植酸和难溶性钙质腐植酸盐中碳官能团的特性分析

Solid state13C nuclear magnetic resonance(NMR)spectroscopy is a common tool to study the structure of soil humic fractions;however,knowledge regarding carbon structural relationships in humic fractions is limited.In this study,mobile humic acid(MHA)and recalcitrant calcium humate(CaHA)fractions were extracted from eight soils collected from six US states and representing a variety of soils and ecoregions,characterized by this spectroscopic technique and analyzed for statistical significance at P≤0.05.We found that the abundances of COO and N–C=O functional groups in the MHA fractions were negatively correlated to soil sand content,but were positively correlated to silt,total N and soil organic carbon contents.In contrast,the abundances of the COO and N–C=O functional groups were only positively correlated to the content of clay in the CaHA fractions,indicating that the two humic fractions were associated with diferent soil components.The two13C NMR peaks representing alkyls and OCH3/NCH were negatively correlated to the peaks representing aromatics,aromatic C–O and N–C=O/COO.Comparison of the sets of data from13C NMR spectroscopy and ultrahigh resolution mass spectrometry revealed that the aromatic components identified by the two methods were highly consistent.The comparison further revealed that protein in MHA was associated with,or bound to,the nonpolar alkyl groups,but a component competitively against(or complementary to)aromatic groups in the MHA composition.These observations provided insight on the internal correlations of the functional groups of soil humic fractions.     

Effects of Soil Texture and CaCO3 on Turnover of Organic Material in Chao Soils

Decomposition experiments of ^14C-labelled sickle alfalfa in chao soils of different texture and these soils after removal of CaCO3 were carried out under field and laboratory conditions respectively.The amount of residual ^14C in,or ^14CO2 evolved from,the soils at intervals after the beginning of devomposition were measured and the distribution of native and labelled C between particle size fractions isolated from these soils was edtermined.Results showed that contents of both labelled (^14C) and non-labelled (^12C) carbon decreased with increasing particle size.The enrichment factor for ^14C was higher than that for ^12C in the clay fraction,the reverse being true for the silt enrichment factors.The effect of soil texture on the decomposition of plant material could not be observed in chao soils when the clay content was lower than 270g kg^-1,while it became obvious once CaCO3 was removed was correlated from these soils.The decomposition rate of plant material in the soil from which the native CaCO3 Was removed was correlated significantly to both the clay content of the soil and the application rate of CaCO3.A preliminary correction equation describing the effect of clay and CaCO3 on the decomposition of organic material in chao soil was derived from the results obtained.     

气候和土壤质地对中国东北地区旱地土壤有机碳影响的尺度效应

Understanding how spatial scale inffuences commonly-observed effiects of climate and soil texture on soil organic carbon (SOC) storage is important for accurately estimating the SOC pool at different scales. The relationships among climate factors, soil texture and SOC density at the regional, provincial, city, and county scales were evaluated at both the soil surface (0-20 cm) and throughout the soil profile (0-100 cm) in the Northeast China uplands. We examined 1022 profiles obtained from the Second National Soil Survey of China. The results indicated that the relationships between climate factors and SOC density generally weakened with decreasing spatial scale. The provincial scale was optimal to assess the relationship between climate factors and SOC density because regional differences among provinces were covered up at the regional scale. However, the relationship between soil texture and SOC density had no obvious trend with increasing scale and changed with temperature. There were great differences in the impacts of climate factors and soil texture on SOC density at different scales. Climate factors had a larger effect on SOC density than soil texture at the regional scale. Similar trends were seen in Heilongjiang and eastern Inner Mongolia at the provincial scale. But, soil texture had a greater effect on SOC density compared with climate factors in Jilin and Liaoning. At the city and county scales, the inffuence of soil texture on SOC density was more important than climate factors.     

Soil particle size range correction for improved calibration relationship between the laser-diffraction method and sieve-pipette method

Particle size fraction(clay, silt, and sand) is an important characteristic that influences several soil functions. The laser-diffraction method(LDM) provides a fast and cost-effective measurement of particle size distribution, but the results usually differ from those obtained by the traditional sieve-pipette method(SPM). This difference can persist even when calibration is applied between the two methods. This partly relates to the different size ranges of particles measured by the two methods as a result of different operational principles, i.e., particle sedimentation according to Stokes’ Law vs. Mie theory for laser beam scattering. The objective of this study was to identify particle size ranges of LDM equivalent to those measured by SPM and evaluate whether new calibration models based on size range correction can be used to improve LDM-estimated particle size fractions, using 51 soil samples with various texture collected from five soil orders in New Zealand. Particle size distribution was determined using both LDM and SPM. Compared with SPM, original data from LDM underestimated the clay fraction(< 2 μm), overestimated the silt fraction(2–53 μm), but provided a good estimation of the sand fraction(53–2 000 μm).Results from three statistical indices, including Pearson’s correlation coefficient, slope, and Lin’s concordance correlation coefficient, showed that the size ranges of < 2 and 2–53 μm defined by SPM corresponded with the < 5 and 5–53 μm size ranges by LDM, respectively. Compared with the traditional calibration(based on the same particle size ranges), new calibration models(based on the corrected size ranges of these two methods) improved the estimation of clay and silt contents by LDM. Compared with soil-specific models(i.e., different models were developed for different soils), a universal model may be more parsimonious for estimating particle size fractions if the samples to be assessed represent multiple soil orders.     

Soil texture prediction through stratification of a regional soil spectral library

Knowing the spatial distribution of soil texture,which is a physical property,is essential to support agricultural and environmental decision making.Soil texture can be estimated using visible,near infrared,and shortwave infrared(Vis-NIR-SWIR)spectroscopy.However,the performance of spectroscopic models is variable because of soil heterogeneity.Currently,few studies address the effects of soil sample variability on the performance of the models,especially for larger spectral libraries that include soils that are more heterogeneous.Therefore,the objectives of this study were to:i)apply Vis-based color parameters on the stratification of a regional soil spectral library;ii)evaluate the performance of the predictive models generated from the spectral library stratification;iii)compare the performance of stratified models(SMs)and the model without stratification(WSM),and iv)explain possible changes in prediction accuracy based on the SMs.Thus,a regional soil spectral library with 1535 samples from the State of Santa Catarina,Brazil was used.Soil reflectance data were obtained by Vis-NIR-SWIR spectroscopy in the laboratory using a spectroradiometer covering the 350–2500 nm spectral range.Sand,silt,and clay fractions were determined using the pipette method.Twenty-two components of color parameters were derived from the Vis spectrum using the colorimetric models.A cubist regression algorithm was used to assess the accuracy of the applicability of the initial models(SMs and WSM)and of the validation between the clusters.Fractional order derivatives(FODs)at 0.5,1.5,and 2 intervals were used to explain possible changes in the performance of the SMs.The SMs with higher contents of clay and iron oxides obtained the highest accuracy,and the most important spectral bands were identified,mainly in the 480–550 and 850–900 nm ranges and the 1400,1900,and 2200 nm bands.Therefore,stratification of soil spectral libraries is a good strategy to improve regional assessments of soil resources,reducing prediction errors in the qualitative determination of soil properties.     

添加黏土及植物残体混合物对沙质土壤中呼吸作用和微生物量碳、氮有效性的影响

Crop yields in sandy soils can be increased by addition of clay-rich soil, but little is known about the effect of clay addition on nutrient availability after addition of plant residues with different C/N ratios. A loamy sandy soil(7% clay) was amended with a clay-rich subsoil(73% clay) at low to high rates to achieve soil mixtures of 12%, 22%, and 30% clay, as compared to a control(sandy soil alone) with no clay addition. The sandy-clay soil mixtures were amended with finely ground plant residues at 10 g kg~(-1): mature wheat(Triticum aestivum L.) straw with a C/N ratio of 68, mature faba bean(Vicia faba L.) straw with a C/N ratio of 39, or their mixtures with different proportions(0%–100%, weight percentage) of each straw. Soil respiration was measured over days 0–45 and microbial biomass C(MBC), available N, and p H on days 0, 15, 30, and 45. Cumulative respiration was not clearly related to the C/N ratio of the residues or their mixtures, but C use efficiency(cumulative respiration per unit of MBC on day 15) was greater with faba bean than with wheat and the differences among the residue mixtures were smaller at the highest clay addition rate. The MBC concentration was lowest in sole wheat and higher in residue mixtures with 50% of wheat and faba bean in the mixture or more faba bean. Soil N availability and soil p H were lower for the soil mixtures of 22% and 30% clay compared to the sandy soil alone. It could be concluded that soil cumulative respiration and MBC concentration were mainly influenced by residue addition, whereas available N and p H were influenced by clay addition to the sandy soil studied.     

Effects of Organic Amendments on Soil Physical Attributes and Aggregate-Associated Phosphorus Under Long-Term Rice-Wheat Cropping

The quantification of phosphorus(P) in bulk soil and P distribution in different size fractions of water-stable aggregates(WSAs)are important for assessing potential P loss through runoff. We evaluated available and total P distribution within WSAs of a sitty clay to clay soil in a long-term fertility experiment of a rice-wheat cropping system in India. Surface soil samples were collected from seven plots amended with NPK fertilizers in combination with or without organic amendments, farmyard manure(FYM), green manure(GM), and paddy straw(PS). The plot with no NPK fertilizers or organic amendments was set as a control. The soil samples were separated by wet sieving into four soil aggregate size fractions: large macroaggregates( 2.0 mm), small macroaggregates(0.25–2.0 mm), fine microaggregates(0.05–0.25 mm), and a silt + clay-sized fraction( 0.05 mm). Structural indices were higher in the soil receiving organic amendments than in the soil receiving inorganic fertilizer alone. Organically amended soil had a higher proportion of stable macroaggregates than the control and the soil receiving inorganic fertilizer alone, which were rich in microaggregates. Total and available P contents within WSAs were inversely related to the aggregate size, irrespective of treatment. The distribution of available and total P in the soil aggregate size fraction was as follows: silt + clay-size fraction small macroaggregates fine microaggregates large macroaggregates. Within a size class, aggregate-associated available and total P contents in the organically amended soil were in the following order: FYM PS ≥ GM. The available P content of the microaggregates( 0.25 mm) was 8-to 10-times higher than that of the macroaggregates( 0.25 mm), and the total P content of the microaggregates was 4-to 5-times higher than that of the macroaggregates. Cultivation without organic amendments resulted in more microaggregates that could be checked by the application of organic amendments such as FYM and GM, which increased the proportion of water-stable macroaggregates by consolidating microaggregates into macroaggregates.     

非无菌覆土对药用菌生长的影响

Ten different casing soils were collected from two soils at two depths (0.2 and 2.0 m below soil surface) to examine the relationships between the physical properties of non-axenic casing soil and yield,number and weight of the medicinal mushroom Agaricus blazei ss.Heinemann.The results showed that soil clay content and bulk density were negatively correlated with the mushroom yield,respectively,but soil silt content and water-holding capacity were found to be positively correlated with the yield.The number of mushrooms was negatively correlated with soil water-holding capacity but positively correlated with soil clay,bulk density and porosity.The weight of mushroom was positively correlated with the content of soil fine sand and negatively correlated with the contents of soil coarse sand,total sand and clay.Neither soil depth nor different soil combinations affected the yield and number of mushrooms,but the mushroom weight was affected by the soil combinations and soil depth,so interplay in the fructification process with the physical characteristics of casing is complicated.     

Soil properties and habitats determine the response of bacterial communities to agricultural wastewater irrigation

Increasing temperatures and variability of precipitation events due to climate change will lead in the future to higher irrigation demands in agroecosystems.However,the use of secondary treated wasterwater(TWW)could have consequences for the receiving soil environment and its resident microbial communities.The objective of this study was to characterize the importance of soil properties and habitats to the response of soil bacteria and archaea to irrigation with TWW.Two agricultural soils with contrasting textures(loamy sand or silt loam)and,for each,three variants differing in soil organic carbon and nitrogen,as generated by long-term fertilization,were analyzed.For each of these six soils,prokaryotic communities from two habitats,i.e.,root-free bulk soil and the rhizosphere of developing cucumber plants in the greenhouse,were characterized.Communities were analyzed by the quantity and diversity of their polymerase chain reaction(PCR)-amplified 16S rRNA genes.To account for TWW-associated nutrient effects,potable water(PW)served as a control.Amplicon sequence analysis showed that prokaryotic communities mainly consisted of bacteria(99.8%).Upon irrigation,regardless of the water quality,prokaryotic diversity declined,p H increased,and no bacterial growth was detected in bulk soil.In contrast,the growth of cucumbers was stimulated by TWW,indicating that plants were the main beneficiaries.Moreover,strong responses were seen in the rhizosphere,suggesting an indirect effect of TWW by altered rhizodepositions.The main bacterial responders to TWW were Proteobacteria,Bacteroidetes,Actinobacteria,and Planctomycetes.Changes in bacterial communities due to TWW were less pronounced in all variants of the silt loam,indicating the importance of clay and soil organic carbon for buffering effects of TWW on soil bacterial communities.Hence,soil organic carbon and soil texture are important parameters that need to be considered when applying TWW in agriculture.     

Beziehungen zwischen Klimafaktoren und C-, N-Pools in Partikelgrößen-Fraktionen zonaler Steppenböden Rußlands

Relationships between climatic factors and C, N pools in particle-size fractions of steppe soils, Russia Many soils of the Russian steppe are characterized by high soil organic matter contents and similar parent material. Thus, they are suitable for investigations of a climatic impact on C and N pools. We sampled 10 topsoils of the zonal Russian steppe at 0–10 and about 50–60 cm depth intervals. After particle-size fractionation into clay (<2 μm), silt (2–20 μm), fine sand (20–250 μm) organic C and N concentrations were determined in bulk soils and fractions. The results suggest that especially the older organic matter of the subsoil (in the silt fraction) is correlated with climatic factors. Topsoils show less evidence for climatic influences on C and N pools. As the ratio of mean annual precipitation to potential evaporation (=N/V) increases, C/N ratios decrease in all fractions and, thus, in the bulk subsoil. Obviously the degree of soil organic matter alteration was more pronounced in the order Greyzem (N/V = 1.0) > Chernozem, Phaeozem (N/V = 0.89) > Haplic Kastanozem (N/V = 0.6) > Calcic (N/V = 0.34), and Gypsic Kastanozem (N/V = 0.32). The organic carbon contents of the bulk subsoil are highest in the subsoil of the Chernozem and Phaeozem, and decrease with increasing N/V ratio (i.e., increasing heat input and dryness) to the Calcic Kastanozem. This is accompanied by an increasing enrichment of organic carbon in the silt fractions (r = ?0.99 for the correlation of the C enrichment in silt with N/V).     

Organic carbon in soil physical fractions under different-aged plantations of Mongolian pine in semi-arid region of Northeast China

In order to understand the changes of surface soil carbon (C) storage following the afforestation of sandy grasslands, we used physical fractionation procedures to quantify C concentrations and sucrase enzyme activity in bulk soil and different particle fractions along two replicate chronosequences of Mongolian pine (Pinus sylvestris var. mongolica Litv.) plantations in the southeastern Keerqin Sand Lands, Northeast China. Carbon concentration in bulk topsoil (0–15 cm) initially decreased following afforestation of grassland and subsequently increased as the forest matured. In general, this pattern of C concentration changes was associated with all particle-size fractions (except clays) and both macro- and microaggregates. The patterns of topsoil C were also influenced by wind erosion and deposition, with marked increases in the relative mass of silt and fine sand fractions occurring during forest development. The loss of aggregates immediately following afforestation was counteracted by formation of aggregates as the forests developed, contributing to the stabilization of carbon. To enhance soil C storage during afforestation of sandy soils in such semi-arid regions it is recommended to minimize disruption of grassland vegetation during the planting stage.     

Straw incorporation and soil organic matter in macro-aggregates and particle size separates

Two field experiments in which straw has been removed or incorporated for 17 yr (loamy sand) and 10 yr (sandy clay loam) were sampled to examine the effect of straw on the C and N contents in whole soil samples, macro-aggregate fractions and primary particle-size separates. The particle size composition of the aggregate fractions was determined. Aggregates were isolated by dry sieving. Straw incorporation increased the number of 1–20 mm aggregates in the loamy sand but no effect was noted in the sandy clay loam. Straw had no effect on the particle size composition of the various aggregate fractions. After correction for loose sand that accumulated in the aggregate fractions during dry sieving, macro-aggregates appeared to be enriched in clay and silt compared with whole soil samples. Because of the possible detachment of sand particles from the exterior surface of aggregates during sieving operations, it was inferred that the particle size composition of macro-aggregates is similar to that of the bulk soil. The organic matter contents of the aggregate fractions were closely correlated with their clay + silt contents. Differences in the organic matter content of clay isolated from whole soil samples and aggregate fractions were generally small. This was also true for the silt-size separates. In both soils, straw incorporation increased the organic matter content of nearly all clay and silt separates; for silt this was generally twice that observed for clay. The amounts of soil C, derived from straw, left in the loamy sand and sandy clay loam at the time of sampling were 4.4 and 4.5 t ha^?1, corresponding to 12 and 21% of the straw C added. The C/N ratios of the straw-derived soil organic matter were 11 and 12 for the loamy sand and sandy clay loam, respectively.     

The influence of different fertilization practices on concentrations of organic carbon and total nitrogen in particle-size fractions during 34 years of a soil formation experiment in loamy marl

Summary The concentrations of organic C and total N in five different particle-size fractions were studied under different mineral and organic fertilizer regimens by examining soil samples from the 34-year-old soil-formation pot experiment Hu 3 in Rostock. The C and N concentrations were generally highest in the clay fraction and decreased in the order medium silt >fine silt >coarse silt and sand. For nearly all years and size fractions the following order was obtained for C and N concentrations under the various fertilizer regimens: Compost >farmyard manure >straw + mineral fertilizer >mineral fertilizer. The various particle-size fractions and fertilizer regimens differed in the development of soil organic matter levels. Consequently, characteristic redistributions were found in the proportions of C and N in the various particle-size fractions, particularly after organic fertilizer was no longer applied (years 20–34). This experimental phase was characterized by decreased organic C and increased total N concentrations, and increased proportions of C and N in the clay-size at the expense of the sand fractions.     

有机肥对棕壤不同粒级有机碳和氮的影响

采集棕壤长期肥料定位试验站不施肥和施用不同用量有机肥的土壤,通过超声波分散—离心分离得到细黏粒(<0.2μm)、粗黏粒(0.2～2μm)、粉粒(2～53μm)、细砂粒(53～250μm)和粗砂粒(250～2000μm)5个颗粒级别后,分析全土及不同粒级中土壤有机碳和氮并进行含量与分布的比较。结果表明,有机质主要分布于黏粒级中,其含量占全土有机碳的42.8%、全氮的58.3%,碳氮比随着粒级的增加而逐渐增大,表明氮易于在小粒级中富集。长期施用有机肥后,全土及各粒级有机碳和氮含量均有显著增加;砂粒级中有机碳和氮的富集系数升高,黏粒级中富集系数降低,粉粒级和砂粒级中的碳氮比降低。增加有机肥的用量加强了全土和各粒级对有机碳和氮的积累,同时加强了粉粒级和砂粒级碳氮比降低的程度。     

Data transformations between soil texture schemes

Various soil texture schemes are in current use. These differ in the size ranges of their particle fractions. There is a need to establish simple methods to correlate these conventional schemes. Therefore I have defined closed-form exponential and power law functions to fit models to cumulative particle-size distribution data. I have tested the functions for their suitability (i) to represent cumulative particle-size distribution curves and (ii) to transfer data between distributions that differ in the size ranges of the particle fractions. I found that closed-form exponential functions adequately represent the cumulative particle-size distributions of fine-textured soils (clay, silty clay, silty clay loam, clay loam, silt loam and loam texture), whilst closed-form power functions better describe the cumulative particle-size distributions of coarse-textured soils (sand, loamy sand, sandy loam, sandy clay and sandy clay loam texture). The functions defined are found to be suitable to transfer data between different texture schemes. The use of this approach is illustrated by examples of data transformations between three widely used soil texture schemes: ISSS, Katschinski's and USDA.     

Characterization of organic matter in topsoils under rain forest and pasture in the eastern Brazilian Amazon basin

 In topsoils under forest and 7-, 12- and 17-year-old pastures, organic matter was characterized by analysing C and N distribution in particle-size fractions, the C decomposition rates of soil and particle-size fractions and by employing density-fractionation of macro-organic matter (>150 μm). The C and N associated with clay fractions increased with increasing age of pasture. The weight (%) of macro-organic matter and its heavy fractions (>1.37 g cm^–3) also increased with increasing age of pasture. However, in a long-term incubation (100 days), these changes seemed to involve an increase in the C decomposition rate in the topsoil of the oldest pasture. Using the C decomposition rates of particle-size fractions, it appeared that silt and clay contributed differently to C decomposition in the whole soil. C associated with silt contributed to the C decomposition rate during the first 40 days of incubation, while C associated with clay contributed to C decomposition in the long-term incubation (after 40 days), especially when the clay fraction appeared to reach saturation point with respect to its ability to bind organic compounds and thus protect the soil from C loss. Received: 13 March 1998     

Land‐use change in subalpine grassland soils: Effect on particulate organic carbon fractions and aggregation

Abandonment of mountain grassland often changes vegetation composition and litter quantity and quality, but related effects on labile soil organic matter (SOM) are largely unknown. The aim of this study was to investigate the impacts of grassland management and abandonment on soil carbon distribution in light (< 1.6 g cm^–3) particulate organic matter (POM) and aggregation along a gradient of management intensity including hay meadows, pastures, and abandoned grasslands. The reduction of management intensity is an interregional phenomenon throughout the European Alps. We therefore selected sites from two typical climate regions, namely at Stubai Valley, Austria (MAT: 3°C, MAP: 1097 mm) and Matsch Valley, Italy (MAT: 6.6°C, MAP: 527 mm), to evaluate effects of land‐use change in relation to climate. Free water‐floatable and free POM (wPOM, fPOM), and an occluded POM fraction (oPOM), were isolated from three water‐stable aggregate size classes (2–6.3 mm, 0.25–2 mm, < 0.25 mm) using density fractionation. Aggregate mean weight diameter slightly decreased with decreasing management intensity. In contrast to absolute POM‐C, fPOM‐C increased in aggregates at both sites with abandonment. Because the oPOM‐C was less affected by abandonment, the ratio of oPOM‐C : fPOM‐C shifted from > 1 to < 1 from meadow to abandoned grassland in aggregates at both sites and thus independent of climate. This suggests that in differently managed mountain grasslands free and occluded POM are functionally different SOM fractions. In bulk soil, the oPOM‐C : fPOM‐C ratio is better suited as an indicator for the response of SOM to management reduction in subalpine grasslands than the total soil C, absolute or relative POM‐C content.     

碱化盐土掺砂对土壤理化性状和玉米产量影响的研究

为解决内蒙古河套平原黏性碱化盐土土壤黏重,作物难以正常生长、产量低下等问题,对河套平原黏性碱化盐土进行了土壤耕层(0~20 cm)掺砂的土壤改良试验,研究掺砂对土壤理化性状和玉米产量的影响。结果表明:试验区土壤掺砂可以降低土壤容重,改变土壤机械组成和土壤质地,提高了黏性碱化盐土的通气孔隙度,改善土壤的通气透水性,降低土壤全盐量和碱化度,有效改善玉米生长环境,提高了玉米的产量。掺砂20%处理的土壤容重从1.64 g/cm3(CK)降低到1.49 g/cm3,土壤通气孔隙度从8.57%提高到18.17%,达到正常范围,使土壤砂粒、粉粒、粘粒含量比例趋向适中,土壤质地由壤质黏土转变为黏壤土,土壤全盐量下降了13%,碱化度降低了21%,玉米产量提高了301%。综合分析,掺砂20%处理对当地碱化盐土改良效果较为适宜。