使用自由软件和便携式光学显微镜研究土壤孔隙特征

Total porosity (TP), determined by image analysis, pore type and pore size distribution were evaluated on impregnated soil blocks from an undisturbed Brazilian sandy loam soil using a digital portable optical microscope. The free software Image J (version 1.40g) was used for image analysis. Procedures for soil image collection and analysis were presented. The image analysis allowed the evaluation of pore sizes with diameters ranging from 20 to >1 000 μm. The following types of pores were also obtained: rounded, elongated and intermediate. The results allowed the characterization of the soil as moderately porous (TP=21.6%). Rounded, intermediate and elongated pores were responsible for 11.6%, 31.7% and 56.7% of TP. In relation to pore size 51.1% of TP was in the 100-500 μm size class and a third of TP came from the pores larger than 500 μm.     

生物炭碳固定于稳定性土壤团聚体中：土壤黏土矿物及其它土壤性质的作用

Aggregation and structure play key roles in water-holding capacity and stability of soils.In this study,the incorporation of carbon(C) from switchgrass biochar into stable aggregate size fractions was assessed in an Aridisol(from Colorado,USA) dominated by 2:1 clays and an Alfisol(from Virginia,USA) containing weathered mixed 1:1 and 2:1 mineralogy,to evaluate the effect of biochar addition on soil characteristics.The biochar was applied at 4 levels,0,25,50,and 100 g kg~(-1),to the soils grown with wheat in a growth chamber experiment.The changes in soil strength and water-holding capacity using water release curves were measured.In the Colorado soil,the proportion of soil occurring in large aggregates decreased,with concomitant increases in small size fractions.No changes in aggregate size fractions occurred in the Virginia soil.In the Colorado soil,C content increased from 3.3 to 16.8 g kg~(-1),whereas in the53 μm fraction C content increased from 5.7 to 22.6 g kg~(-1) with 100 g kg~(-1)biochar addition.In the Virginia soil,C content within aggregate size fractions increased for each size fraction,except the2 000 μm fraction.The greatest increase(from 6.2 to 22.0 g kg~(-1)) occurred in the 53–250 μm fraction.The results indicated that C was incorporated into larger aggregates in the Virginia soil,but remained largely unassociated to soil particles in the Colorado soil.Biochar addition had no significant effect on water-holding capacity or strength measurements.Adding biochar to more weathered soils with high native soil organic content may result in greater stabilization of incorporated C and result in less loss because of erosion and transport,compared with the soils dominated by 2:1 clays and low native soil organic content.     

利用方式和土壤肥力对土壤团聚体和养分的影响

The size distribution of water-stable aggregates and the variability of organic C, N and P contents over aggregate size fractions were studied for orchard, upland, paddy, and grassland soils with high, medium, and low fertility levels. The results showed that > 5 mm aggregates in the cultivated upland and paddy soils were 44.0% and 32.0%, respectively, less than those in the un-tilled orchard soil. Organic C and soil N in different size aggregate fractions in orchard soil with high fertility were significantly higher than those of other land uses. However, the contents of soil P in different size aggregates were significantly greater in the paddy soil as compared to the other land uses. Soil organic C, N and P contents were higher in larger aggregates than those in smaller ones. The amount of water-stable aggregates was positively correlated to their contribution to soil organic C, N and P. For orchard and grassland soils, the > 5 mm aggregates made the greatest contribution to soil nutrients, while for upland soil, the 0.25-0.053 mm aggregates contributed the most to soil nutrients. Therefore, the land use with minimum disturbance was beneficial for the formation of a better soil structure. The dominant soil aggregates in different land use types determined the distribution of soil nutrients. Utilization efficiency of soil P could be improved by converting other land uses to the paddy soil.     

铵、钾同时存在时, 土壤对铵的优先吸附

The water stability of aggregates in various size classes separated from 18 samples of red soils under different managements, and the mechanisms responsible for the formation of water-stable soil aggregates were studied. The results showed that the water stability of soil aggregates declined with increasing size, especially for the low organic matter soils. Organic matter plays a key role in the formation of water-stable soil aggregates. The larger the soil aggregate size, the greater the impact of organic matter on the water stability of soil aggregates. Removal of organic matter markedly disintegrated the large water-stable aggregates (> 2.0 mm) and increased the small ones (< 0.25-0.5mm) to some extent, whereas removal of free iron(aluminium) oxides considerably destroyed aggregates of all sizes, especially the < 0.25-0.5 mm classes. The contents of organic matter in water-stable aggregates increased with aggregate sizes. It is concluded from this study that small water-stable aggregates (< 0.25-0.5 mm) were chiefly cemented by Fe and Al oxides whilst the large ones (> 2.0 mm) were mainly glued up by organic matter. Both free oxides and organic matter contribute to the formation and water stability of aggregates in red soils.     

中国亚热带红壤团聚体稳定性与土壤化学性质的关系

The stability of aggregates in the surface soil is crucial to soil erosion and runoff generation. Thus, to understand the stability and the breakdown mechanisms of soil aggregates as well as the relationship between aggregate stability and selected soil chemical properties, such as different forms of Fe and Al oxides, organic matter, CEC and clay content, the aggregates of slightly and severely eroded red soils derived from Quaternary red clay in subtropical China were analyzed using the routine wet sieving and the Le Bissonnais methods. The results indicated that the aggregates of the severely eroded soils were more stable than those of the slightly eroded soils. Different aggregate breakdown mechanisms resulted in different particle size distribution. The slaking from entrapped air in aggregates severely destroyed the soil aggregates, especially in the slightly eroded soils. Meanwhile, mechanical breakdown and microcracking had little effect on the aggregates compared to slaking. The fragments resulting from slaking were mainly microaggregates that increased in size with increasing clay content. The main fragment size of the slightly eroded soils was 1.0-0.2 mm, while for the severely eroded soils it was 5.0-2.0 mm and 1.0-0.5 mm. Overall, more than 20% of the fragments were smaller than 0.2 mm. In addition, aggregate stability was positively and often significantly correlated with Fe_d, Al_d, Fe_o and clay content, but significantly and negatively correlated to SOC.     

土壤微生物对不同粒径、不同表面和孔隙性质生物炭的响应

Biochars are known for their heterogeneity, especially in pore and surface structure associated with pyrolysis processes and sources of feedstocks. The surface area of biochar is likely to be an important determinant of the extent of soil microbial attachment, whereas the porous structure of biochar is expected to provide protection for soil microorganisms. Potential interactions between biochars from different sources and with different particle sizes were investigated in relation to soil microbial properties in a short-term incubation study. Three particle size(sieved) fractions(0.5–1.0, 1.0–2.0 and 2.0–4.0 mm) from three woody biochars produced from jarrah wood,jarrah and wandoo wood and Australian wattle branches, respectively, were incubated in soil at 25?C for 56 d. Observation by scanning electron microscopy(SEM) and characterisation of pore and surface area showed that all three woody biochars provided potential habitats for soil microorganisms due to their high porosity and surface areas. The biochars were structurally heterogeneous,varying in porosity and surface structure both within and between the biochar sources. After the 56-d incubation, hyphal colonisation was observed on biochar surfaces and in larger biochar pores. Soil clumping occurred on biochar particles, cementing and covering exposed biochar pores. This may have altered surface area and pore availability for microbial colonisation. Transient changes in soil microbial biomass, without a consistent trend, were observed among biochars during the 56-d incubation.     

Effects of porous clay ceramic rates on aeration porosity characteristics in a structurally degraded soil under greenhouse vegetable production

Soil structure degradation in greenhouse vegetable fields reduces vegetable production. Increasing aeration porosity is the key to ameliorating soil structure degradation. Thus, we tested the effect of a porous material, porous clay ceramic(PLC), on the amelioration of soil structure degradation under greenhouse vegetable production. A 6-month pot experiment was conducted with four PLC application levels based on volume, i.e., 0%(control), 5%(1 P), 10%(2 P), and15%(3 P) using Brassica chinensis as the test plant. At the end of the experiment, soil columns were sampled, and the aeration pore network was reconstructed using X-ray computed tomography(CT). The degree of anisotropy(DA), fractal dimension(FD), connectivity, aeration porosity, pores distribution, and shape of soil aeration pores and plant biomass were determined. The DA, FD, and connectivity did not significantly differ as the PLC application rate increased.Nonetheless, aeration porosity significantly linearly increased. The efficiency of PLC at enhancing soil aeration porosity was 0.18% per Mg ha~(-1). The increase in aeration porosity was mainly due to the increase in pores 2 000 μm, which was characterized by irregular pores. Changes in aeration porosity enhanced the production of B. chinensis. The efficiency of PLC at increasing the plant fresh weight was 0.60%, 3.06%, and 2.12% per 1% application rate of PLC for the 1 P, 2 P, and 3 P treatments, respectively. These results indicated that PLC is a highly efficient soil amendment that improves soil structure degradation by improving soil aeration under greenhouse conditions. Based on vegetable biomass, a 10% application rate of PLC was recommended.     

喷灌和畦灌对冬小麦农田表层土壤结构的影响

A two-year experiment was carried out on the effect of sprinkler irrigation on the topsoil structure in a winter wheat field. A border-irrigated field was used as the control group. The total soil porosity, pore size distribution, pore shape distribution, soil cracks and soil compaction were measured. The sprinkler irrigation brought significant changes to the total soil porosity, capillary porosity, air-filled porosity and pore shape of topsoil layers in comparison with the border irrigation. The total porosity and air-filled porosity of the topsoil in the sprinkler irrigation were higher than those in the border irrigation. The changes in the air-filled and elongated pores were the main reasons for the changes in total porosity. The porosities of round and irregular pores in topsoil under sprinkler irrigation were lower than those under border irrigation. Sprinkler irrigation produced smaller soil cracks than border irrigation did, so sprinkler irrigation may restrain the development of macropore flow in comparison with border irrigation. The topsoil was looser under sprinkler irrigation than under border irrigation. According to the conditions of topsoil structure, it is preferable for crops to grow under sprinkler irrigation than under border irrigation.     

用激光衍射法评价有机物和和碳酸盐对土壤团聚的作用

>Aggregation in many soils in semi-arid land is affected by their high carbonate contents.The presence of lithogenic and/or primary carbonates can also inffuence the role of soil organic matter(SOM) in aggregation.The role of carbonates and SOM in aggregation was evaluated by comparing the grain-size distribution in two carbonate-rich soils(15% and 30% carbonates) under conventional tillage after different disaggregating treatments.We also compared the effect of no-tillage and conventional tillage on the role of these two aggregating agents in the soil with 30% of carbonates.Soil samples were treated as four different ways:shaking with water(control),adding hydrochloric acid(HCl) to remove carbonates,adding hydrogen peroxide(H2O2) to remove organic matter,and consecutive removal of carbonates and organic matter(HCl + H2O2),and then analyzed by laser diffraction grain-sizing.The results showed that different contributions of carbonates and SOM to aggregate formation and stability depended not only on their natural proportion,but also on the soil type,as expressed by the major role of carbonates in aggregation in the 15% carbonate-rich soil,with a greater SOC-to-SIC(soil organic C to soil inorganic C) ratio than the 30% carbonate-rich soil.The increased organic matter stocks under no-tillage could moderate the role of carbonates in aggregation in a given soil,which meant that no-tillage could affect the organic and the inorganic C cycles in the soil.In conclusion,the relative role of carbonates and SOM in aggregation could alter the aggregates hierarchy in carbonate-rich soils.     

Aggregate Stability and Its Relationship with Some ChemicalProperties of Red Soils in Subtropical China

The stability of aggregates in the surface soil is crucial to soil erosion and runoff generation. Thus, to understand the stability and the breakdown mechanisms of soil aggregates as well as the relationship between aggregate stability and selected soil chemical properties, such as different forms of Fe and A1 oxides, organic matter, CEC and clay content, the aggregates of slightly and severely eroded red soils derived from Quaternary red clay in subtropical China were analyzed using the routine wet sieving and the Le Bissonnais methods. The results indicated that the aggregates of the severely eroded soils were more stable than those of the slightly eroded soils. Different aggregate breakdown mechanisms resulted in different particle size distribution. The slaking from entrapped air in aggregates severely destroyed the soil aggregates,especially in the slightly eroded soils. Meanwhile, mechanical breakdown and microcracking had little effect on the aggregates compared to slaking. The fragments resulting from slaking were mainly microaggregates that increased in size with increasing clay content. The main fragment size of the slightly eroded soils was 1.0-0.2 mm, while for the severely eroded soils it was 5.0-2.0 mm and 1.0-0.5 mm. Overall, more than 20% of the fragments were smaller than 0.2 mm.In addition, aggregate stability was positively and often significantly correlated with Fed, Ald, Feo and clay content, but significantly and negatively correlated to SOC.     

中国三类典型稻田CH4排放的稳定性碳同位素变化

Little is known about the stable carbon isotopes of methane(CH4) emitted(δ~(13)CH_(4emitted)) from permanently flooded rice fields and double rice-cropping fields.The CH4 emission and corresponding δ~(13)CH_(4emitted) under various field managements(mulching,water regime,tillage,and nitrogen(N) fertilization) were simultaneously measured in three typical Chinese rice fields,a permanently flooded rice field in Ziyang City,Sichuan Province,Southwest China,a double-rice cropping field in Yingtan City,Jiangxi Province,Southeast China,and a rice-wheat rotation field in Jurong City,Jiangsu Province,East China,from 2010 to 2012.Results showed different seasonal variations of δ~(13)CH_(4emitted) among the three fields during the rice-growing season.The values of δ~(13)CH_(4emitted) were negatively correlated with corresponding CH4 emissions in seasonal variation and mean,indicating the importance of CH_4 production,oxidation,and transport associated with isotopic fractionation effects to the δ~(13)CH_(4emitted).Seasonal variations of δ~(13)CH_(4emitted) were slightly impacted by mulching cultivation,tillage,and N application,but highly controlled by drainage.Meanwhile,tillage,N application,and especially mulching cultivation had important effects on seasonal mean CH4 emissions and corresponding δ~(13)CH_(4emitted) with low emissions accompanied by high values of δ~(13)CH_(4emitted).Seasonal mean values of δ~(13)CH_(4emitted) from the three fields were similar,mostly ranging from —60‰ to — 50‰,which are well in agreement with previously published data.These demonstrated that seasonal variations of δ~(13)CH_(4emitted) mainly depended on the changes in CH4 emission from rice fields and further indicated the important effects of methanogenic pathways,CH4 oxidation,and CH4 transport associated with isotope fractionation effects influenced by field managements on δ~(13)CH_(4emitted).     

液面上部气体的置换对土壤厌氧培养下的N2O和CO2排放的影响

To study effect of C2H2 and change of headspace gas on N2O emission,denitrification,as well as CO2 emission,slurries of an agricultural soil were anaerobically incubated for 7 days at 25℃.Both N2O reduction and CO2 emissions were inhibited by the addition of 100 mL L^-1 of C2H2.However,the inhibition to CO2 emission was alleviated by the replacement of headspace gas,and the N2O emission was enhanced by the replacement.Acetylene disappeared evidently from the soil slurries during the incubation.Consequently results obtained from the traditional C2H2 blocking technique for determination of denitrifcation rate,especially in a long-time incubation,should be explained with care because of its side effect exsting in the incubation environments without change of headspace gas.To reduce the possible side effect on the processes other than denitrification ,it is suggested that headspace gas should be replaced several times during a long-time incubation.     

土壤非交换态钾与结构态钾能够区分吗？

Nonexchangeable K (NEK) is the major portion of the reserve of available K in soil and a primary factor in determining soil K fertility. The questions of how much NEK is in soils and how to quantify total NEK in soils are so far still unclear due to the complicated effects of various minerals on K fixation. In this study, the NEK in 9 soils was extracted with sodium tetraphenylboron (NaBPh₄) for various time periods longer than 1 d. The results showed that the NEK extracted by NaBPh₄ gradually increased with time, but showed no more increase after the duration of extraction exceeded 10--20 d. As the temperature increased from 25 to 45 ^oC, the duration to obtain the maximum extraction of NEK was reduced from 20 to 10 d, and the maximum values of NEK released at both temperatures was almost the same for each soil. The maximum NEK (MNEK) of the 9 soils extracted by NaBPh4 varied from 3 074 to 10 081 mg kg^-1, accounting for 21%--56% of the total soil K. There was no significant correlation between MNEK released by NaBPh₄ and other forms of K, such as NH₄OAc-extracted K, HNO₃-extracted K and total K in soils, which indicates that NEK is a special form of K that has no inevitable relationship to the other forms of K in soils. The MNEK extraction by NaBPh₄ in this study indicated that the total NEK in the soils could be differentiated from soil structural K and quantified with the modified NaBPh₄ method. The high MNEK in soils made NEK much more important in the role of the plant-available K pool. How to fractionate NEK into different fractions and establish the methods to quantify each NEK fraction according to their bioavailability is of great importance for future research.     

中国亚热带中部三峡库区不同土地利用方式下甲烷氧化潜力研究

To compare the CH4 oxidation potential among diferent land uses and seasons,and to observe its response to monsoon precipitation pattern and carbon and nitrogen parameters,a one-year study was conducted for diferent land uses (vegetable field,tilled and non-tilled orchard,upland crops and pine forest) in central subtropical China.Results showed significant diferences in CH4 oxidation potential among diferent land uses(ranging from 3.08 to 0.36 kg CH4 ha-1 year-1).Upland with corn-peanut-sweet potato rotation showed the highest CH4 emission,while pine forest showed the highest CH4 oxidation potential among all land uses.Non-tilled citrus orchard (0.72±0.08 kg CH4 ha-1 year-1)absorbed two times more CH4 than tilled citrus orchard(0.38±0.06kg CH4 ha-1 year-1).Irrespective of diferent vegetation,inorganic N fertilizer application significantly influenced CH4 fluxes across the sites (R2=0.86,P=0.002).Water-filled pore space,soil microbial biomass carbon,and dissolved nitrogen showed significant efects across diferent land uses (31% to 38% of variability)in one linear regression model.However,their cumulative interaction was significant for pine forest only,which might be attributed to undisturbed microbial communities legitimately responding to other variables,leading to net CH4 oxidation in the soil.These results suggested that i)natural soil condition tended to create win-win situation for CH4 oxidation,and agricultural activities could disrupt the oxidation potentials of the soils;and ii)specific management practices including but not limiting to efficient fertilizer application and utilization,water use efciency,and less soil disruption might be required to increase the CH4 uptake from the soil.     

浮萍对福州平原稻田CH4和N2O排放的影响分析

浮萍是稻田中常见的漂浮在水面的水生植物,具有固氮作用,但是,浮萍对稻田温室气体排放的影响尚不明确.以位于湿润亚热带的福州平原稻田为研究对象,探讨浮萍对该区域稻田CH4和N2O排放的影响,为科学评价、准确编制我国水稻田温室气体排放清单提供基础数据.研究结果表明,观测期内,有萍小区和无萍小区CH4排放范围分别为0.19～26.50 mg·m-2·h-1和1.02～28.02 mg·m-2·h-1,平均值分别为9.28 mg·m-2·h-1和11.66 mg·m-2·h-1,有萍小区CH4排放低于无萍小区(P＜0.01),有萍小区CH4排放高峰比无萍小区约提前1周,高峰期后排放迅速降低;有萍小区和无萍小区N2O排放范围分别为-50.11～201.82 μg·m-2·h-1和-28.93～54.42μg·m-2·h-1,平均值分别为40.29 μg·m-2·h-1和11.93 μg·m-2·h-1,有萍小区N2O排放高于无萍小区(P＜0.05).稻田排干后,N2O排放迅速上升,2个小区N2O排放呈现出相似的规律.有萍小区和无萍小区的CH4与N2O排放的影响因子有所不同.综合考虑CH4和N2O两种温室气体,CH4仍是稻田温室效应产生的主要贡献者,浮萍可降低位于沿海区域的福州平原稻田综合温室效应的17.3％.     

盐碱地土壤：氧化亚氮和二氧化碳排放的潜在来源？

Increasing salt-affected agricultural land due to low precipitation,high surface evaporation,irrigation with saline water,and poor cultural practices has triggered the interest to understand the influence of salt on nitrous oxide(N_2O) and carbon dioxide(CO_2)emissions from soil.Three soils with varying electrical conductivity of saturated paste extract(EC_e)(0.44-7.20 dS m~(-1)) and sodium adsorption ratio of saturated paste extract(SARe)(1.0-27.7),two saline-sodic soils(S2 and S3) and a non-saline,non-sodic soil(S1),were incubated at moisture levels of 40%,60%,and 80%water-filled pore space(WFPS) for 30 d,with or without nitrogen(N)fertilizer addition(urea at 525 μg g~(-1) soil).Evolving CO_2 and N2 O were estimated by analyzing the collected gas samples during the incubation period.Across all moisture and N levels,the cumulative N_2O emissions increased significantly by 39.8%and 42.4%in S2 and S3,respectively,compared to S1.The cumulative CO_2 emission from the three soils did not differ significantly as a result of the complex interactions of salinity and sodicity.Moisture had no significant effect on N_2O emissions,but cumulative CO_2 emissions increased significantly with an increase in moisture.Addition of N significantly increased cumulative N_2O and CO_2 emissions.These showed that saline-sodic soils can be a significant contributor of N_2O to the environment compared to non-saline,non-sodic soils.The application of N fertilizer,irrigation,and precipitation may potentially increase greenhouse gas(N2O and CO_2) releases from saline-sodic soils.     

基于DNDC模型的华北典型农田氮素损失分析及综合调控途径

氮素损失对农业生产造成的影响已成为当前研究的热点,模型是对氮素损失影响评价及定量化研究的有效手段。利用华北典型农田冬小麦-夏玉米轮作种植模式的作物产量、氮素淋失量等田间观测数据对DNDC模型进行了验证,并采用验证后的DNDC模型对该种植模式的氮素损失进行了定量评价,提出了综合考虑作物产量、氮素淋失量、N2O排放量以及NH3挥发损失的综合调控途径。结果表明,DNDC模型较好地模拟了冬小麦-夏玉米轮作系统作物的产量、氮素淋失的动态变化规律,以及土壤中NO3--N和NH4+-N的残留量,说明DNDC已具备模拟农田生态系统中土壤氮素生物地球化学过程的能力。模型模拟结果表明,在传统农业管理措施下,氮素通过淋失、N2O排放以及NH3挥发损失的量分别达到49.4 kg(N).hm-2.a-1、17.71kg(N).hm-2.a-1和144.8 kg(N).hm-2.a-1。综合考虑氮素损失途径,提出了适合当地农业生产条件的最优化管理措施,即减小当前常规施氮量到340 kg(N).hm-2.a-1,提高玉米秸秆还田率到100%,并保持灌溉量不变。相比常规管理措施,最优化管理措施氮素淋失量为14.1 kg(N).hm-2.a-1,降低71.5%,N2O排放量为14.91kg(N).hm-2.a-1,降低15.8%,NH3挥发损失量为117.2 kg(N).hm-2.a-1,降低19.1%,而对作物产量基本不造成明显影响。该评价结果可直接用于农业生产实践。     

土壤中汞的化学形态及其影响因素

An investigation and on 13-year-old(1984-1996) Chinese fir and Tsoong‘s tree mixed forests in Jianou City,Fujian Province,China was carried out to compare the influences of different interplanting types of individual tree-tree,row-row,row-strip(three rows)and pure Chinese fir stands on soil properties.Compared with the pure stands of Chinese fir ,the mixed stands exerted a posivtive effect on soil fertility,with increases in soil organic matter,total N,available P and available K.Moreover,improvements were also observed in soil enzymatic activities ,aggregate structure,structure,stability,status of soil porosity,soil aeration and penetrability in miexd stands.The row-row interplanted stands had the best effect on tree growth and soil properties among these mixed forests.In the southern subtropical region,the spreading of the row-row mixing model of the two tree species would be helpful to preventin ghe soil from fertility deterioratio caused by successive plantation of Chineses fir.     

外加碳酸盐增加石灰性土壤密闭培养过程中CO2的释放量

The closed-jar incubation method is widely used to estimate the mineralization of soil organic C. There are two C pools (i.e., organic and inorganic C) in calcareous soil. To evaluate the effect of additional carbonates on CO2 emission from calcareous soil during closed-jar incubation, three incubation experiments were conducted by adding different types (CaCO3 and MgCO3 ) and amounts of carbonate to the soil. The addition of carbonates significantly increased CO2 emission from the soil; the increase ranged from 12.0% in the CaCO3 amended soil to 460% in the MgCO3 amended soil during a 100-d incubation. Cumulative CO2 production at the end of the incubation was three times greater in the MgCO3 amended soil compared to the CaCO3 amended one. The CO2 emission increased with the amount of CaCO3 added to the soil. In contrast, CO2 emission decreased as the amount of MgCO3 added to the soil increased. Our results confirmed that the closed-jar incubation method could lead to an overestimate of organic C mineralization in calcareous soils. Because of its effect on soil pH and the dissolution of carbonates, HgCl2 should not be used to sterilize calcareous soil if the experiment includes the measurement of soil CO2 production.     

2个马铃薯杂交组合F1的SSR鉴定

杂交育种是马铃薯新品种选育的重要方法, 其杂种F₁真实性鉴定是获得目标性状单株的关键环节。为选育优质、高产、抗病性及抗旱性强的马铃薯新品种, 用马铃薯品种"费乌瑞它"(Favorita)分别与"J07-6"和"陇薯3号"杂交, 获得了杂种F1代。本试验利用SSR标记技术对"Favorita"×"J07-6"、"Favorita"×"陇薯3号"2个杂交组合F1共86个单株的真实性进行了鉴定。试验从43对SSR引物中筛选出2对适宜引物STM1049和S7。利用这2对引物进行PCR扩增, 将"Favorita"×"J07-6"杂交种F1和"Favorita"×"陇薯3号"杂交种F1的SSR带型划分为双亲互补型、缺失型、父本型和母本型4种类型。依据SSR带型特征, 从"Favorita"×"J07-6"和"Favorita"×"陇薯3号"2个杂交组合F₁单株中分别鉴定出真杂种34个和27个, SSR分子标记技术用于马铃薯杂交种真实性鉴定是可靠的。该研究结果可为马铃薯杂交种优良株系选育提供依据。