华北某些旱地硫库的组成

Soil sulfur fractions,including monocalcium phosphate-extractable S,slowly soluble inorganic S,C-O-S,C-bonded S and unidentified organic S,were analyzed for 48 soils,as representatives of 6 major groups of upland soils,fluvisol,cinnamon soil,loessial soil,chestnut soil,black soil and brown soil,in North china,The contents of total S and monocalcium phosphate-extractalble S in the above 48 soils ranged from 234 to 860 and 5.1to 220.3mg kg^-1,respectively and each of 6 soil groups contained the samples with a low level of phosphate-extractable S.Great differences in the average contents of each fraction of S were observed among the above 6 soil groups.Expressed as average percentage of the total S in soils,fluvisols,cinnamon soils,loessial soils,chestnut soils,black soils and brown soils contained 6.1%,9.5%,5.7%,13.2%,3.5%and 6.8% monocalcium phosphate-extractable S,5.7%,3.0%,9.3%,10.4%,3.2%and 3.1% slowly soluble inorganic S,51.6%,26.7%,17.4%,31.2%,28.9%and 22.7% C-O-S,11.0%,9.1%,6.6%,6.8%,9.7%and 9.4% in C-bonded S,and 25.6%,51.7%,60.8%,38.4%,54.7%and 53.0% unidentifed organic S,respectively,FOr the above 6 groups of soils,the mean C/N ratios were remarkably similar,ranging from 9.7 to 10.7,while the mean N/S ratios ranged from 1.16 to 3.12,The highest ratios of C/N,C/C-O-S and C/C-bonded S were found in black soils.averaging 30.4,104.9and 314.7,respectively,while the lowest ratios arose in chestnut soil,averaging 12.4,39.7 and 183.3,respectively.     

有机物质对土壤溶液中铜形态的影响

Incubation of two soils,a red soil derived from granodiorte and a fluvo-aquic soil from alluvial deposit,with rice straw,Chinese milk vetch and pig manure under submerged condition were conducted to study the species of Cu in soil solutions as affected by the organic materials.The organic materials increased total soluble Cu by raising dissolved organic carbon(DOC) in soil solution when the solution pH values were below the range in which Cu deposited quickly.When the solution pH rose to this rage,the increase of DOC did not raise total soluble Cu.Total soluble Cu in all the treatments dropped with incubation time.After adding organic materials labile Cu dropped with incubation time and decreased sharply in the pH range of Cu precipitation.Addition of organic materials enhanced slowly labile Cu but depressed the ratio of labile Cu to total soluble Cu.Slowly labile Cu decreased with incubation time.Sepwise multiple linear regression analysis showed that total soluble Cu was positively correlated with Eh and DOC(P=0.0025),labile Cu was negatively correlated with pH(P=0.0118),and slowly labile Cu was positively correlated with Eh and DOC(P=0.0022).Both the labile and slowly labile Cu were correlated with total soluble Cu at extremely significant levels.     

水分含量对秸秆还田土壤碳矿化和微生物特性的影响

An 80-d incubation experiment was conducted to investigate straw decomposition,the priming effect and microbial characteristics in a non-fertilized soil(soil 1) and a long-term organic manure-fertilized soil(soil 2) with and without13 C-labeled maize straw amendment under different moisture levels. The soil 2 showed a markedly higher priming effect,microbial biomass C(Cmic),and β-glucosidase activity,and more abundant populations of bacteria and fungi than the soil 1. Also,soil CO2 emission,Cmic,β-glucosidase activity,and bacterial and fungal population sizes were substantially enhanced by straw amendment. In the presence of straw,the amount of straw mineralization and assimilation by microbes in the soil at 55% of water holding capacity(WHC) were significantly higher by 31% and 17%,respectively,compared to those at 25% of WHC. In contrast,β-glucosidase activity and fungal population size were both enhanced as the moisture content decreased. Cmicdecreased as straw availability decreased,which was mainly attributed to the reduction of straw-derived Cmic. Amended soils,except the amended soil 2 at 25% of WHC,had a more abundant fungal population as straw availability decreased,indicating that fungal decomposability of added straw was independent of straw availability. Non-metric multidimensional scaling analysis based on fungal denatured gradient gel electrophoresis band patterns showed that shifts in the fungal community structure occurred as water and straw availability varied. The results indirectly suggest that soil fungi are able to adjust their degradation activity to water and straw availability by regulating their community structure.     

Effect of Submergence on Iron Transformation and Phosphorus Availability in Calcareous Soils

A thermostatic incubation experiment was carried out to estimate the effects of flooding periods,stalk application and P addition of Fe transformation and P availability in calcareous soils.Submergence increased amorphous Fe,especially in the case of stalk application.The newly formed amorphous Fe with a great surface area played an important role in Psorption;and submergence also stimulated the dissolution of inorganic P,thus increasing the availability of soil P in calcareous soils.Meanwhile,a part of soluble P was absorbed and fixed again on the surface of newly formed amorphous Fe,thus resulting in a decrease of P availability.Soil rapidly available P increased after 150-day incubation.There existed significantly negative correlations between soil amorphous Fe content and soil Fe-P and rapidly available P contents.Submerged conditions promoted the transformation of inorganic P added toward Fe-P in calcareous soils,especially in the case of stalk application.     

长期稻秆还田对土壤微生物量及C、N动力学的影响

A study was performed on the long-term effect of straw incorporation on soil microbial biomass C contents, C and N dynamics in both Rothamsted and Woburn soils. The results showed that for both soils, the microbial biomass C contents were significantly different among all the treatments, and followed the sequence in treatments of straw chopped and incorporated into 10 cm (CI10) > straw burnt and incorporated into 10 cm (BI10) > straw chopped and incorporated into 20 cm (CI20) > straw burnt and incorporated into 20 cm (BI20). Laboratory incubation of soils showed that the cumulative CO₂ evolution was closely related to the soil microbial biomass C content. Carbon dioxide evolution rates (CO₂-C, μg (g•d)^-1) decreased rapidly in the first two weeks' incubation, then decreased more slowly. The initial K₂SO₄-extractable NH₄-N and NO₃-N contents were low and similar in all the treatments, and all increased gradually with the incubation time. However, net N immobilization was observed in chopped treatments for Rothamsted soils during the first 4 weeks. Nevertheless, more N mineralization occurred in Treatment CI10 than any other treatment at the end of incubation for both soils. The Woburn soils could more easily suffer from the leaching of nitrate because the soils were more permeable and more N was mineralized during the incubation compared to the Rothamsted soils.     

稻田土壤甲烷排放模型: Ⅱ. 模型的验证和应用

Fifteen upland soils collected from the major arable areas in NOrth China were used to assess the availability of soil sulfur(S) to plants in a pot experiment.Soils were extracted with various reagents and the extractable S was determined using turbidimetric method or inductively coupled plasma atomic emission spectrometry (ICP-AES),respectively.In addition,mineralizable organic S,organic S,N/S ratio,sulfur availability index(SAI) and available sulfur correction value(ASC) in soils were also determined.The S amout extracted by 1.5g L^-1 CaCl2 was nearly equivalent to that by 0.25mol L^-1 KCl(40℃),and both of them were slightly smaller than that by 0.01 molL^-1 Ca(H2PO4)2 solution,as measured by turbidimetric method or ICP-AES.The extractable S measured by turbidimetric method was consistently smaller than that by ICP-AES.All methods tested except that for organic S and N/S ratio produced satisfactoy results in the regression analyses of the relationships between the amounts of S extracted and plant dry matter weight and S uptake in the pot experiment,In general,0.01 mol L^-1 Ca(H2PO4)2-extracted S determined by ICP-AES or turbidimetric method and 0.25mol L^-1 KCl(40℃)-extracted S determined by ICP-AES appeared to be the best indicators for evaluation of soil available S.     

氨的固定对土壤微生物氮的测定的影响

The effect of ammonium fixation on the estimation of soil microbial biomass N was studied by the standard fumigation-incubation(FI) and fumigation-extraction (FE) methods,NO3-N content of fumigated soil changed little during incubation,while the fixed NH4^ in soils capable of fixing NH4^ increased with the increase of K2SO4-extractable NH4-N.one day fumigation increased both extractable NH4^ and fixed NH4^ ,However,prolonged fumigation gave no further increase.One day fumigation caused significant loss of NO3-N,while prolonged fumigation caused no further loss.For soils tested,the net increases of fixed NH4^ in fumigated soil equaled to 0-94% of NH4-N flush measured by the FI metod,and 1-74% of extractable N measured by the FE method.depending on different soils.It is concluded that the ammonium fixation was one of the processes taking place in soils during fumigation as well as incubation ofter fumigation and should not be neglected in the estimation of microbial biomass nitrogen by either FI or FE method.     

Effect of controlled-release urea on heavy metal mobility in a multimetal-contaminated soil

Controlled-release N fertilizers can affect the availability of heavy metals in the contaminated paddy soil.A soil incubation experiment was conducted to investigate the effects of prilled urea(PU),S-coated urea(SCU),and polymer-coated urea(PCU)on the solubility and availability of heavy metals Cd,Pb,Cu,and Zn in a multimetal-contaminated soil.The results showed that the application of different coated urea significantly affected the solubility and availability of heavy metals.At 5 d of incubation,the application of PU,SCU,and PCU had significantly decreased the concentrations of water-soluble and available Cd,Pb,Cu,and Zn,when compared with the control.At 60 d of incubation,the depletory effects of PU on water-soluble and available heavy metals had reduced,and the initial decrease in the concentrations of water-soluble Cd,Pb,Cu,and Zn caused by SCU had changed to an increase.The concentrations of water-soluble Pb,Cu,and Zn in the SCU-treated soil were higher than those in the control.Application with PCU led to a higher water-soluble Cu than that in the control,while the available Cd,Pb,and Zn were lower than those in the control.The effect of different coated urea was much stronger on the water solubility of the heavy metals than on their availability.The effects of controlled-release urea on the transformation of heavy metals resulted in changes in the concentrations of NH4^+,water-soluble SO4^2-,and soil p H.The results further suggested that PCU could be used in dry farming operations in multimetal-contaminated acid soils.     

有机物料对淹水土壤中施入的镉形态的影响

The effect of three organic materials(rice straw,Chinese milk vetch and pig manure)on the fractionation of cadmium added into two soils(a red soil and a fluvo-aquic soil) was studied using submerged incubation experiment.The organic materials increased soil soild organic carbon(SOC),pH value,the concentration of active Si in all the treatments and active Fe and Mn in some treatments.Accumulated SOC caused directly the increase of Cd bound to solid organic matter and consequently the decrease of exchangeable Cd.Higher active Si and pH,as well as lower Eh,were also responsible for the reduction of exchangeable Cd.Cd bound to mn oxide was positively correlated with pH values and rose significantly after one-month incubation,but decreased after three-month incubation.Cd bound to amporphous Fe oxide increased with the incubation time,but was not affected significantly by adding organic materials.     

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.     

土壤中不同形态硫的生物有效性研究

在温室条件下连续种植 4茬玉米和水稻幼苗 ,分别研究好气和淹水条件下土壤无机硫(MCP-S)和有机硫包括酯键硫 (C-O-S)、碳键硫 (C-S)和未知态有机硫 (UO-S)的转化及生物有效性。结果表明 ,植物吸硫总量和植株含硫量从第一茬至第四茬逐渐下降 ,这与土壤MCP-S含量下降有关 ,而与土壤有机硫各组分的变化无关。种植期间土壤MCP-S的含量也是逐渐下降 ,种植水稻时下降的幅度小于种植玉米 ;土壤有机硫组分如C-O-S、C-S和UO-S从第一茬到第四茬逐渐下降 ,种植 4茬后 ,玉米和水稻的吸硫总量远大于土壤MCP-S的下降量 ,其高出部分来源于土壤有机硫的矿化。C-O-S、C-S和UO-S对植物都是有效的 ,各组分有机硫对玉米和水稻幼苗吸硫的表观贡献为:C-O-SC-SUO-S。淹水条件下有机硫对水稻的贡献大于好气条件下对玉米的贡献     

稻秆还田及土壤预淹对施入土壤的(15NH4)2SO4-N的去向及水稻生长的影响

A pot experiment was conducted to investigate the effects of straw incorporation and soil pre-flooding on the fate of (15NH4)2SO4-N and the growth of rice.Excessive application of rice straw when incorporated with(^15 NH4)2 SO4 at the C/N ratio of 40 reduced the loss of (^15NH4)2SO4-N and retarded the growth and development of rice significantly,while no adverse effects were observed on dry weight of panicle and the total recovery of (15NH4)2 SO4-N when rice straw was incorporated with(15NH4)2SO4 at a C/N ratio less than 25.There were no significant effects of duration of soil pre-flooding within 6 weeks on (^15NH4)2 SO4-N uptake by rice and on rice growth,but,less loss of (^15NH4)2SO4-N was observed in the soil with a longer period of pre-flooding.     

土壤有机硫形态分配的季节变化与作物效应

江淮丘陵地区下蜀黄土母质发育的水稻土油 稻轮作试验表明：油菜收获后土壤比试验前土壤总有机硫及碳键硫、硫酸酯和惰性硫组分含量分别下降了51.3% 、60.2% 、29.3%和73.4%;水稻收获后土壤比油菜收获后土壤总有机硫及碳键硫、硫酸酯和惰性硫组分含量分别增加了129% 、302% 、78%和203% 。与试验前土壤比较,油菜收获后土壤有机硫、碳键硫和惰性硫占总硫百分数分别下降了12.6、3.2和18.7个百分点,碳键硫和惰性硫占总有机硫百分数分别下降了2.3和18.7个百分点;而硫酸酯形态硫占总硫和有机硫百分数则分别增加了8.9和20.7百分点。与油菜收获后土壤比较,水稻收获后土壤总有机硫、碳键硫和惰性硫占总硫百分数分别增加了7.4 、6.9和7.7个百分点,碳键硫和惰性硫占总有机硫百分数分别增加了7.7和7.2个百分点;而硫酸酯形态硫占总硫和总有机硫百分数则分别减少了21.2和14.9个百分点。与同期不种作物处理相比,油菜收获后和油 稻轮作后土壤硫酸酯形态硫含量、占总硫及占有机硫百分数分别增加12.4个百分点和64.1个百分点,7.2和14.5个百分点及10.8和17.9个百分点而土壤惰性硫占总硫百分数下降9.6和13.6个百分点,占有机硫百分数则增加12.8和18.6个百分点。虽然油菜种植导致耕层土壤有机硫有显著下降,而其在水稻种植期间被逆转。因此,油-稻轮作制度是维持该地区土壤硫肥力的一种较好耕作措施之一。     

土壤有机硫形态分配的季节变化与作物效应

江淮丘陵地区下蜀黄土母质发育的水稻土油 稻轮作试验表明:油菜收获后土壤比试验前土壤总有机硫及碳键硫、硫酸酯和惰性硫组分含量分别下降了51.3% 、60.2% 、29.3%和73.4%;水稻收获后土壤比油菜收获后土壤总有机硫及碳键硫、硫酸酯和惰性硫组分含量分别增加了129% 、302% 、78%和203% 。与试验前土壤比较,油菜收获后土壤有机硫、碳键硫和惰性硫占总硫百分数分别下降了12.6、3.2和18.7个百分点,碳键硫和惰性硫占总有机硫百分数分别下降了2.3和18.7个百分点;而硫酸酯形态硫占总硫和有机硫百分数则分别增加了8.9和20.7百分点。与油菜收获后土壤比较,水稻收获后土壤总有机硫、碳键硫和惰性硫占总硫百分数分别增加了7.4 、6.9和7.7个百分点,碳键硫和惰性硫占总有机硫百分数分别增加了7.7和7.2个百分点;而硫酸酯形态硫占总硫和总有机硫百分数则分别减少了21.2和14.9个百分点。与同期不种作物处理相比,油菜收获后和油 稻轮作后土壤硫酸酯形态硫含量、占总硫及占有机硫百分数分别增加12.4个百分点和64.1个百分点,7.2和14.5个百分点及10.8和17.9个百分点而土壤惰性硫占总硫百分数下降9.6和13.6个百分点,占有机硫百分数则增加12.8和18.6个百分点。虽然油菜种植导致耕层土壤有机硫有显著下降,而其在水稻种植期间被逆转。因此,油-稻轮作制度是维持该地区土壤硫肥力的一种较好耕作措施之一。     

Sequential transformation rates of soil organic sulfur fractions in two-step mineralization process

To understand the organic sulfur (S) stabilization in volcanic soils, we investigated organic S transformation rates and their relationships to soil properties in incubation experiments using forest soils from the Nikko volcanic region, central Japan. We hypothesized that carbon (C)-bonded S would first be transformed into ester sulfate-S and then into inorganic sulfate-S. We separately calculated the rates of decrease of C-bonded S (velocity 1, v ₁) and ester sulfate-S (velocity 2, v ₂) concentrations. During incubation, the ester sulfate-S concentration increased in two soils characterized by a high concentration of both ammonium oxalate-extractable aluminum (Al_o) and pyrophosphate-extractable Al (Al_p), whereas the C-bonded S concentration decreased in all soils. A large proportion of the S that was lost in the incubation experiments consisted of C-bonded S rather than ester sulfate-S. Velocity 2 was negatively correlated with both of Al_o and Al_p contents when soils were incubated at 20 °C. These results suggest that when C-bonded S is transformed into ester sulfate-S, complete mineralization to inorganic sulfate is inhibited, because ester sulfate-S is stabilized due to organo–mineral association. Incubation temperatures significantly affected v ₂. Thus, production of inorganic sulfate by mineralization of ester sulfate-S appeared to be regulated by soil Al contents and temperatures. Velocity 1 was proportional to soil pH ranging from 4.5 to 5.5, indicating that the degradation of C-bonded S is pH dependent.     

添加不同外源氮对长期秸秆还田土壤中氮素转化的影响

【目的】秸秆还田能够改变土壤中各活性氮库的含量与比例,进而影响土壤氮素供应能力。本文研究了长期秸秆还田条件下添加不同外源氮对土壤中不同形态氮素的影响,旨在明确长期秸秆还田土壤活性氮库的含量差异。【方法】长期定位施肥试验点位于湖南省望城县(112°80′N、28°37′E,海拔高度100 m)。试验开始于1981年,供试土壤为第四纪红色黏土发育的水稻土,轮作制度为稻—稻—冬闲。2014年晚稻收获后,采集单施化肥和长期秸秆还田配施化肥两个处理的耕层土壤样品,开展室内培养试验。每个土壤样品设置灭菌和不灭菌两组主处理,在主处理下设:对照(CK)、添加尿素(N 150 kg/hm^2,U)、添加秸秆(N 150 kg/hm^2,S)和添加尿素和秸秆(N 300 kg/hm^2,U+S)四个副处理,4次重复。在25℃下恒温培养5、10、20、30、50、90、130天时,分析土壤铵态氮、硝态氮、微生物氮和可溶性有机氮含量。【结果】1) U、S和U+S处理均显著提高土壤铵态氮和硝态氮含量,高低顺序为U> U+S> S> CK。非灭菌条件下,U处理的土壤铵态氮含量较其他处理高出90.8%~288%。2)灭菌后土壤铵态氮长期维持在较高水平,其向硝态氮转化过程受阻。在培养90天内,土壤硝态氮、微生物氮和可溶性有机氮含量均处于较低水平。3)而不灭菌条件下,各处理土壤硝态氮均在培养50天后迅速增加,至培养结束土壤硝态氮达最大值(117.43~243.17 mg/kg)。4)土壤微生物氮和可溶性有机氮分别于培养20天(106.72~244.01 mg/kg)和30天(95.76~140.63 mg/kg)时达到最大值。5)至培养结束,灭菌条件下长期NPKS土壤中U+S处理可溶性有机氮显著高于其他处理,较U和S处理分别提高51.55%和29.96%。【结论】添加不同外源氮有利于提高长期秸秆还田土壤中活性有机氮的含量,尤其是添加秸秆和尿素处理,能够显著提高土壤氮素的供应能力。     

麦秸配施纤维素降解细菌对果园土壤有机碳库及生化特性的影响

  目的  研究果园土壤有机碳库及生化性质对小麦秸秆还田配施不同纤维素降解细菌的响应特点。  方法  以豫北碱性果园土壤为研究对象,采用室内培养法,以不添加麦秸及纤维素降解菌为对照（CK）,研究仅添加麦秸（S）及麦秸分别配施尼氏芽孢杆菌（Bacillus nealsonii,S + B）、科恩氏菌（Cohnella,S + C）、灿烂类芽孢杆菌（Paenibacillus lautus,S + P）处理对土壤有机碳含量、酶活性、速效养分含量及盐碱性的影响。  结果  培养100 d内有机碳矿化速率呈现先升高后下降的趋势,且与一级动力学模型高度拟合。麦秸配施纤维素降解菌处理的土壤有机碳矿化速率、累计矿化量及潜在可矿化碳含量均高于S处理。S + B处理的土壤总有机碳、微生物量碳、水溶性有机碳和易氧化有机碳含量分别比S处理提高10.14%、35.53%、26.27%和24.34%。麦秸配施纤维素降解菌提高土壤碳库管理指数和土壤酶活性,其中S + B处理的纤维素酶、碱性磷酸酶及脱氢酶活性均显著高于S处理。与仅添加麦秸相比,麦秸配施纤维素降解菌显著增加土壤速效氮、磷、钾及可交换性镁含量,降低可交换钙含量和pH值。土壤速效氮、磷及微生物量碳是影响有机碳矿化的主要因素。  结论  麦秸配施纤维素降解菌显著提高土壤有机碳库活度及含量,改善土壤生化性质,以尼氏芽孢杆菌的促进作用相对较高。     

不同有机物料投入下黄河故道土壤有机碳积累特征的研究

【目的】黄河故道潮土区土壤有机质含量低、结构差是限制当地作物优质高产的重要问题,通过连续施用不同有机物料,探究不同有机物料投入下,黄河故道区典型土壤的有机质积累特征,为该区土壤的快速固碳提供理论依据和参考方案。【方法】试验共设置7个处理：单施NPK肥作为对照(CK),其他处理在单施NPK肥的基础上增施有机肥6000 kg/hm_² (M1)、有机肥12000 kg/hm_² (M2)、树枝菌渣6000 kg/hm_² (B1)、树枝菌渣12000 kg/hm_² (B2)、秸秆菌渣6000 kg/hm_² (S1)、秸秆菌渣12000 kg/hm_² (S2), 采用随机区组设计。【结果】与CK相比,外源有机物料施入会显著增加玉米产量和有机质含量,增幅范围分别为21.7%～58.3%和37.4%～70.1%,产量的增加直接导致进入土壤的秸秆残渣及根茬碳相应增加38.9 kg/hm_²～76.9 kg/hm_²,致使 B2处理增产保肥效果最佳。就有机物料种类而言,用量为12000 kg/hm_²的树枝菌渣对土壤活性有机质的提升幅度最大,比相同用量的有机肥和秸秆菌渣高26.2%和57.0%,秸秆菌渣的碳库管理指数最高,但与树枝菌渣相比无显著差异。树枝菌渣由于碳氮比高,在土壤中分解慢,相同用量下,矿化消耗的碳量低于秸秆菌渣和有机肥,单位碳投入下的呼吸量比秸秆菌渣和有机肥低42.3%和29.3%。【结论】用量为12000 kg/hm_²的树枝菌渣由于碳投入量大,矿化消耗少,对黄河故道潮土有机质提升效果最好,玉米增产最明显。     

水稻-油菜轮作模式下秸秆还田替代钾肥的效应

【目的】研究稻-油轮作条件下秸秆还田配施钾肥对水稻和冬油菜产量、 地上部钾素累积量、 钾肥利用率以及土壤钾素含量的影响,明确长期秸秆还田替代钾肥的效果,为秸秆还田下稻-油轮作中钾肥的合理施用提供科学依据。【方法】2011~2014年在湖北省粮油主产区-江汉平原选择土壤供钾能力较高的农田,布置水稻-冬油菜轮作定位试验。试验共设7个处理,分别为: 1)CK(-K); 2)+K; 3)+S; 4)S+1/4K; 5)S+1/2K; 6)S+3/4K和7)S+K。其中K和S分别表示钾肥和还田秸秆,K2O用量为90 kg/hm2。【结果】 1)与不施钾(-K)相比,施用钾肥和秸秆还田均不同程度地增加了水稻和冬油菜年均产量和钾素吸收量,尤以秸秆还田配施钾肥处理(S+K)的水稻和冬油菜产量和地上部钾素吸收量最高,与对照(-K)相比增产率分别为12.8%和19.1%; 地上部钾素(K2O)累积吸收量增幅分别达到35.7%和79.3%。2)在当前推荐钾肥用量条件下,秸秆还田对水稻和冬油菜的钾肥吸收利用率没有显著影响,但均使两种作物的钾素吸收利用率显著降低。与秸秆不还田相比,秸秆还田后水稻季的钾肥与钾素农学利用率明显降低,而冬油菜季则分别显著提高与持平; 秸秆还田后,水稻季的钾素农学利用率显著降低,而冬油菜季则持平。3)通过对秸秆还田条件下钾肥用量与增产率、 地上部吸钾量增幅的相关分析得出秸秆还田后当前的推荐钾肥用量偏高。根据肥效模型并结合实际产量和农田钾素养分平衡拟合得出,水稻和冬油菜的年均适宜钾肥用量分别为52.0和61.9 kg/hm2,比推荐用量可分别减少42.2%和31.2%。【结论】在土壤钾素含量较高的情况下,稻-油轮作区开展连续秸秆还田不仅能够降低钾肥投入量,获得较高的粮油经济产量,还可以提高土壤有效钾含量并维持农田系统养分平衡以及秸秆钾素资源的良性循环。