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1.
In order to study the effect of plant growth promoting rhizobacteria (PGPR), vermicompost and phosphate sources on the growth and nutrients uptake by lettuce, a greenhouse experiments was conducted. Treatments consisted of PGPR (Pseudomonas fluorescens) (with and without inoculation), vermicompost (0 and 1% w/w) and phosphate sources (control, rock phosphate (RP), tricalcium phosphate and triple super phosphate (TSP) at 25 mg P kg?1 level). Biological fertilizers, RP and TSP significantly increased shoot dry matter (SDM) and some measured nutrients uptake. Co-application of PGPR and RP, in non-vermicompost treatments significantly increased SDM, shoot nitrogen, phosphorus (P), potassium, zinc and manganese uptake rates. Shoot P uptake had no significant difference between TSP and RP treatments. Co-application of PGPR, vermicompost and TSP significantly decreased SDM, which may be due to the P toxic levels in the plant aerial parts and/or the inhibition of the bacterial activities in the rhizosphere soil.  相似文献   

2.
We evaluated the effects of microbial inoculants in a loess soil amended with various phosphorus (P) sources on pea growth and P uptake (PU). Treatments included factorial combinations of three treatments (noninoculation, NI; bacteria, BA; and fungi, FU) and three P sources (no P, NP; calcium superphosphate, SP; and rock phosphate, RP). Compared with NI, soils inoculated with BA and FU and receiving NP and SP increased pea shoot and total biomass, with greater increases with BA than with FU. Both BA and FU stimulated root growth, regardless of P addition. Compared to NI, PU with BA increased by 26, 59, and 83% in soils amended with RP, SP, and NP, respectively, whereas with FU it increased by 25% with SP and 48% with NP, with no effects with RP. The results indicate that BA can increase bioavailability of soil P, whereas FU may promote plant utilization of bioavailable P existing in soil.  相似文献   

3.
通过对小麦/玉米轮作不同施磷水平7年14季定位试验土壤养分状况的分析与评价,探讨石灰性潮土有效磷耗竭和积累状况下土壤全磷、无机磷分级形态的变化规律,并运用通径分析和逐步回归分析,研究Olsen法、Mehlich3法、树脂交换法测定的土壤有效磷与各无机磷形态的关系。结果表明:(1)与初始土壤相比,N0P0K0、N2P0K2处理全磷总量分别降低了15.2%,29.7%,无机磷总量降低了13.5%,11.8%,N2P2K2、N2P3K2处理全磷总量分别增加了8.2%,27.2%,无机磷总量增加了11.1%,27.8%。供试土壤无机磷含量以Ca_(10)-P、Ca_8-P为主,施用磷肥可提高Ca_2-P、Ca_8-P、Al-P、Fe-P占无机磷总量的相对比例。(2)磷耗竭状态下,植物利用的无机磷来源于缓效磷源(Ca_8-P、Al-P、Fe-P;75%)、无效磷源Ca_(10)-P(11.5%~14.0%)、速效磷源Ca_2-P(7.5%~8.9%);无机磷盈余状态下,积累的无机磷主要转化为Ca_8-P(50%~70%)、Al/Fe-P(10%~23%)、O-P(8%)、Ca_2-P(0.2%~1.8%)。(3)Ca_2-P、AlP对3种方法测得的有效磷均具有正向作用且贡献率较大。Olsen法测定的无机磷主要是Ca_2-P、Ca_8-P,Mehlich3法主要是Ca_2-P、Ca_8-P、Al-P,阴离子交换树脂法主要是Ca_2-P、Fe-P。(4)Olsen法、Mehlich3法、树脂交换法均适于评价土壤有效磷水平,Olsen法最优。  相似文献   

4.
Introducing specific microorganisms into the soil ecological system is an important strategy for improving nutrient use efficiency. Two pot experiments were conducted in the greenhouse from December 3, 2012 to January 25, 2013 (Experiment 1) and March 11 to April 23, 2013 (Experiment 2) to evaluate the effect of nitrogen (N) source and inoculation with plant growth-promoting rhizobacteria (PGPR) on plant growth and N and phosphorus (P) uptake in tomato (Lycopersicon esculentum Mill.) grown on calcareous soils from South Florida, USA. Treatments included urea, controlled release urea (a controlled release fertilizer, CRF) each at low and high N rates and with or without inoculation of PGPR. A mixture of PGPR strains Bacillus amyloliquefaciens IN937a and Bacillus pumilus T4 was applied to the soil during growing periods of tomato. Treatments with PGPR inoculation increased plant height compared to treatments without PGPR in both experiments. Inoculation with PGPR increased shoot dry weight and shoot N uptake for the same N rate and N source. In both experiments, only at high N rate, CRF and urea treatments with PGPR had significantly (P < 0.05) greater shoot biomass than those without PGPR. Only at high N rate, CRF treatment with PGPR significantly increased shoot N uptake by 39.0% and 10.3% compared to that without PGPR in Experiments 1 and 2, respectively. Meanwhile, presence of PGPR in the soil increased shoot P uptake for all treatments in Experiment 1 and for most treatments in Experiment 2. In Experiment 1, only at low N rate, CRF treatment with PGPR significantly increased shoot P uptake compared with that without PGPR. In Experiment 2, a significant increase in shoot P uptake by inoculation of PGPR was only observed in CRF treatment at high N rate. Results from this study indicate that inoculation with PGPR may increase plant growth and N and P uptake by tomato grown on calcareous soils. However, the effect of PGPR varied and was influenced by many factors such as N source, N rate, and soil fertility. Further investigations are warranted to confirm the effect of PGPR under different soil conditions.  相似文献   

5.
长期施肥对石灰性潮土无机磷形态的影响   总被引：14，自引：3，他引：14  
在河北省辛集市马兰农场的肥料长期定位试验点上 ,进行了石灰性土壤在无机磷耗竭和积累状况下 ,无机磷形态的转化及其在土壤剖面中的分步规律和施肥的影响。结果表明 ,在土壤磷处于耗竭的情况下 ,植物主要吸收利用了土壤的Ca8-P、Al-P、Fe-P和Ca2-P ,只有在极度缺磷的情况下 ,植物才利用土壤中的Ca10-P ,而O-P是土壤中极稳定的无机磷形态 ,植物一般不能利用。长期单施无机磷肥 ,土壤无机磷含量有所提高 ,积累的无机磷约 60%转化成Ca10-P和O-P。有机肥与化肥配合施用 ,积累的无机磷约有占积累无机磷的 2/3转化成Ca2-P和Ca8-P ,而且各形态无机磷的含量在土壤表层和下层均有所提高 ,一般随有机肥用量的增加 ,下层土壤无机磷的增加幅度也大 ,且影响的深度也较深。但在本试验条件下 ,施肥深度的影响不会超过50cm。  相似文献   

6.
It is desirable to know the distribution of phosphorus (P) fractions in soil so that plants may use P efficiently. Here we report the dynamics of inorganic and organic P in P-deficient black and rice soil cropped by soybean, white lupin, and maize supplied with nitrogen (N) inputs by N fixation and urea fertilizer. Inorganic P fractions of the three cropped soils could be ranked as O-P (organic phosphorus) > Al-P (aluminum phosphorus) > Fe-P (iron phosphorus) > Ca10-P (calcium-10 phosphorus) > Ca8-P (calcium-8 phosphorus) > Ca2-P (calcium-2 phosphorus), irrespective of soil type. The potential of various inorganic P fractions to plant nutrition differed between soybean and white lupin. The percentage of total P present as inorganic P was affected by crop, soil type, and N source. In black soil, the change of organic P fraction induced by N fixation was larger than by urea application. The moderately labile organic P (MLOP) concentration was not affected significantly by soil type and crop species, and it was probably the main P source to the inorganic P fraction because the correlation between the two pools was high (r = 0.945; P < 0.05). Crop species differed in their uptake of inorganic and organic P from soil. Though P fraction concentrations varied between black soil and rice soil, their response to crop species and N source was similar. The amounts of P removed from soil were affected by N source. The right choice of crop species and the application a suitable N source may increase crop yield and P uptake by plant in P-deficient soils.  相似文献   

7.
VA菌根真菌对石灰性土壤不同形态磷酸盐有效性的影响   总被引：12，自引：0，他引：12  
用32P示踪法研究了VA菌根真菌对石灰性土壤不同形态磷酸盐有效性的影响。结果表明，VA菌很真菌显著增加了玉米吸收肥料和土壤的磷量。菌根植物和非菌根植物都可不同程度地吸收利用土壤中的Ca2-P、Ca8-P、Fe-P和Al-P，VA菌根真菌增加了玉米对它们的吸收。试验结果还表明，施Ca10-P时接种VA菌很真菌对玉米生长的促进作用比施用其它磷酸盐明显，但Ca10-P不能直接被玉米植株所利用。说明VA菌根真菌能提高土壤中的有效性磷（Ca2-P和Al-P）和缓效性磷（Ca8-P和Fe-P）的有效性。  相似文献   

8.
间作作物菌根菌丝对红壤磷形态的影响   总被引：1，自引：0，他引：1  
丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)在植物与土壤系统中扮演着重要的角色,能促进寄主植物对养分尤其是磷(P)的吸收。间作在提高土壤P素利用及增产增收等方面具有重要作用。本研究通过三室隔网分室盆栽模拟试验,在玉米/大豆间作种植体系下,对菌丝室进行不同形态P处理[不施P(P0)、施用无机磷(IOP50)、施用有机磷(OP50)],同时在根室进行不同AMF处理[不接种(NM)、接种Funneliformis mosseae(FM)],研究了不同外源形态P添加和AMF处理下,菌根作物对菌丝室红壤中不同形态P吸收利用的影响。结果表明:与单作-FM-IOP50处理相比,间作-FM-IOP50处理下的玉米P吸收量显著增加150.2%,大豆P吸收量增加24.5%;除大豆单作-P0处理外,接种FM均明显降低菌丝室土壤有效磷含量。除大豆单作-FM处理外,施用IOP50使土壤有效磷含量在单作条件下最高,而在间作条件下则最低。对红壤P形态的分级结果表明,接种AMF均一定程度增加了Ca_2-P、Al-P、Org-P、O-Al-P、Ca_(10)-P的含量,而间作则显著提高了作物对土壤Ca_2-P、Fe-P的吸收;相比其他处理,土壤Ca_2-P、Org-P、O-Al-P含量在间作-FM-IOP50组合处理下较高(P0.05)。相关分析显示,Ca_2-P与玉米植株P吸收量呈显著负相关,而O-Al-P与大豆植株P吸收量呈显著负相关。总之,接种FM、磷肥施用与间作均在一定程度上促进了宿主作物对P的吸收累积。其中间作-FM-IOP50组合是促进间作玉米生长、P素吸收及Ca_2-P、Org-P、O-Al-P增加的最佳组合,通过促进无机磷的活化而改善作物对P素的吸收利用,有效削减土壤P素的残留,若将其应用于滇池流域,可望减少P素的流失。  相似文献   

9.
以山西省晋城市采煤塌陷区复垦土壤为研究对象,连续3年定位施肥研究施用有机肥(M)、无机肥(NPK)、有机肥+无机肥(NPK+M)对土壤理化性状、土壤磷分级的影响。结果表明:试验结束后,不同施肥处理土壤的pH、容重、全氮、全磷含量差异均不显著;单施有机肥处理的有机质含量显著高于单施化肥处理;有机肥+无机肥处理土壤速效磷含量高于其余处理,但处理间差异不显著。有机肥+无机肥处理能够明显提高土壤无机磷组分Ca_8-P含量;不同施肥处理均显著提高了Fe-P,处理间差异不显著;各处理的O-P、Ca_(10)-P增幅不明显;对照处理的不同无机磷组分含量总体保持下降趋势,其中Ca_8-P、Fe-P降幅较为明显。有机肥处理对活性、中活性组分,有机肥+无机肥处理对活性、中稳性有机磷效果明显,无机肥对有机磷组分效果不显著。相关性分析表明,Ca_2-P、Ca_8-P、Al-P、Fe-P、中活性、中稳性有机磷与速效磷均呈显著正相关性,Ca_8-P、中活性有机磷与速效磷极显著相关。  相似文献   

10.
在黄土旱塬区长期试验(1985-1997年)中,选取对照(不施肥,CK)、磷肥(P2O5.60.kg/hm2,P)、氮肥(N.120kg／hm2,N)、氮磷(N,120.kg／hm2,P2O5,60.kg/hm2,NP)、氮磷有机肥(N.120.kg/hm2,P2O560.kg/hm2,有机肥75.t／hm2,NPM),种植方式为冬小麦连作的5种有代表性的施肥处理,研究了石灰性土壤磷素吸附特性的演变及其与土壤磷素形态、土壤有机碳(SOC)含量的关系。结果表明,P素的最大吸附量(Qm),1997年对照(CK)、N处理比1985年分别提高了18％和14％;而P、NP和NPM处理分别降低了26％、13％和24％。吸附能常数(k值)随时间延长,对照和N处理相对稳定,P和NP处理呈升高趋势,而NPM处理有降低趋势。土壤磷素吸附饱和度(DPS)和零净吸附磷浓度(EPC0)对照和N处理随时间延长呈降低趋势,P、NP和NPM处理呈升高趋势。Qm与Ca8-P、Al-P存在极显著相关关系(P0.001),与Ca2-P、Pe-P存在显著相关关系(P0.05)。Ca2-P、有机磷含量变化与土壤DPS的相关性达到显著水平(P0.05)。EPC0只与有机磷间存在显著的相关关系(P0.05)。Qm、DPS和EPC0变化与SOC存在显著或极显著的线性相关关系(P0.001)。  相似文献   

11.
长期施肥对黑垆土无机磷形态的影响研究   总被引：9，自引：0，他引：9       下载免费PDF全文
王平  李凤民  刘淑英  吴银明  王娟 《土壤》2005,37(5):534-540
对黄土高原旱地黑垆土进行25年长期定位肥料试验,对土壤无机P形态、数量和对作物的有效性进行了研究。结果表明,石灰性土壤无机P的组成以Ca10-P占绝对优势,约占无机P总量的57.7%,其次是闭蓄态P(O-P),占17.9%,而Al-P、Fe-P、Ca8-P分别占5.9%、5.7%、10.1%,最少的为Ca2-P,只有2.8%。所有施肥处理中,各形态无机P均以土粪 NP含量最高;Ca2-P、Ca8-P、Al-P以N处理最低,而Fe-P、O-P、Ca10-P以CK处理最低;长期施肥对无机P各组分相对含量也有影响,耗P处理主要是Ca2-P、Ca8-P、Al-P的降低,而施P处理是Ca10-P的降解和Ca2-P的积累。与1990年比较,CK处理均有下降;N处理除O-P、Ca10-P有增加外,其他各组分含量均下降;而NP、秸杆. NP、土粪、土粪. NP处理均呈增加趋势。不同处理对土壤有效P和缓效态P均有不同程度的影响,而与无效态P关系不大。同时做了各形态无机P与作物产量的相关性分析,在各级无机P与产量的相关性中,Ca2-P、Ca8-P、Al-P都达到了极显著水平,其中以Ca8-P与产量的相关性最高,而Fe-P、O-P、Ca10-P也都达到了显著水平。  相似文献   

12.
Abstract

Plants grown in acidic soil usually require relatively high amounts of available phosphorus (P) to optimize growth and productivity, and sources of available P are often added to meet these requirements. Phosphorus may also be made available at relatively high rates in native soil when roots are colonized with arbuscular mycorrhizal fungi (AMF). Addition of P to soil usually reduces root‐AMF colonization and decreases beneficial effects ofAMF to plants. In glasshouse experiments, soil treatments of P [0 P (Control), 50 mg soluble‐P kg?1 as KH2PO4 (SP), and 200 mg P kg?1 as phosphate rock (PR)], organic matter (OM) at 12.5 g kg?1, AMF (Glomus darum), and various combinations of these (OM+SP, OM+PR, AMF+SP, AMF+PR, AMF+OM, AMF+OM+SP, and AMF+OM+PR) were added to steam treated acidic Lily soil (Typic Hapludult, pHw=5.8) to determine treatment effects on growth and mineral acquisition by chickpea (Cicer areitinum L.). The various treatment applications increased shoot dry matter (DM) above the Control, but not root DM. Percentage AMF‐root colonization increased 2‐fold or more when mycorrhizal plants were grown with AMF, OM+SP, and OM+PR. Regardless of P source, plant acquisition of P, sulfur (S), magnesium (Mg), calcium (Ca), and potassium (K) was enhanced compared to the Control, and mineral enhancement was greater in PR compared to SP plants. Mycorrhizal plants also had enhanced acquisition of macronutrients. OM+SP and OM+PR enhanced acquisition of P, K, and Mg, but not Ca. Concentrations of Fe, Mn, Cu, and Al were generally lower than Controls in SP, RP, AMF+PR, AMF+SP, and OM plants, and mycorrhizal plants especially had enhanced micronutrients. Relative agronomic effectiveness values for shoot DM and shoot P, Ca, and Mg contents were considerably higher for PR, including OM+PR, AMF+PR, and AMF+OM+PR, than for SP. PR and OM applications to AMF plants are low‐cost attractive and ecologically sound alternatives to intensive use of P fertilizers for crops grown in acidic soils.  相似文献   

13.
Changes of inorganic phosphorus forms and the characteristics of phosphorus adsorption and desorption were studied under a long-term fertilization experiment in black soil. Results showed that the forms of inorganic phosphorus ranged as O–P < Ca2–P < Ca8–P < Al–P < Ca10–P < Fe–P. Therefore, Fe–P was the main inorganic phosphorus form in this study. The capacity of phosphorus adsorption with phosphate treatments was higher than with no-phosphorus treatments. The optimal fitted equation was the Langmuir equation. Phosphorus desorption was related to the binding energy. Positive correlation between phosphorus adsorption and desorption without phosphorus addition was found; however, negative correlations among the phosphate treatments had been observed.  相似文献   

14.
土壤磷固定是影响石灰性磷肥肥效的主要原因。本文在田间滴灌条件下采用连续浸提的方法对液体磷肥和固体颗粒磷肥及其不同施用方法对石灰性土壤各形态无机磷含量动态变化的影响进行了研究,并比较了不同处理下加工番茄磷素营养效应。结果表明:各施肥处理0—20 cm土层Ca2-P和Ca8-P含量随施肥时间明显下降,而Ca10-P含量则显著上升,表明磷肥在石灰性土壤中不断向Ca10-P转化并被固定。液体磷肥追肥处理0—20 cm土层Ca2-P含量在各时期均显著高于其他施肥处理(P＜0.05),且液体磷肥追肥可以明显保持土壤0—20 cm土层较高的Ca8-P含量。与其他施肥处理相比,液体磷肥追施可减少石灰性土壤对磷的固定,增加0—20 cm土层Ca2-P和Ca8-P含量(P＜0.05),显著提高土壤磷的有效性。液体磷肥追施处理可显著提高加工番茄叶片含磷量和经济产量(91725 kg/hm2)。与传统过磷酸钙颗粒磷肥作基肥处理（CK1）相比,液体肥料全做追肥可使加工番茄经济产量提高26.7%,并明显提高了磷肥利用率。在滴灌条件下石灰性土壤上液体磷肥分次追施比传统的固体颗粒磷肥基施具有明显的优势,是一种非常具有应用前景的施肥方式。  相似文献   

15.
Shen  Yan  Duan  Yinghua  McLaughlin  Neil  Huang  Shaomin  Guo  Doudou  Xu  Minggang 《Journal of Soils and Sediments》2019,19(7):2997-3007
Purpose

Calcareous soils are characterized by high pH and phosphorus (P) fixation capacity. Increasing application of P fertilizer recently has significantly improved soil P concentration, especially available P (Olsen-P) and inorganic phosphate (Pi) fractions. However, there are few data available on the ability of soils with different initial Olsen-P levels to continuously supply P (i.e., P desorption capacity) to crops without additional P fertilization and on which Pi fraction exerts the greatest influence on P desorption capacity.

Materials and methods

Five soils with different initial Olsen-P levels (0.5, 14.3, 38.4, 55.4, 72.3 mg kg?1, hereafter refer as OP1, OP2, OP3, OP4, and OP5) but similar other soil properties were selected to evaluate the capacity of P desorption and its relationship with Pi fractions. Soil P was sequentially extracted once daily for 16 consecutive days using Olsen solution.

Results and discussion

The content and proportions of dicalcium phosphate fraction (Ca2-P), octacalcium phosphate fraction (Ca8-P), aluminum phosphorus fraction (Al-P), and iron phosphorus fraction (Fe-P) in Pi increased significantly with the increase of initial Olsen-P (P?<?0.01). Applied P fertilizer was mostly stored as Ca8-P in the soil. Soil P desorbed reached an equilibrium after 16 extractions for all soils, and P desorption capacity (12–358 mg kg?1) showed a significant linear relationship with initial Olsen-P (P?<?0.01), with an increase of 4.2 mg kg?1 desorbed P per 1 mg kg?1 increase of initial Olsen-P. Ca2-P exerted the conclusive effect on P desorption in the first four extractions, but Ca8-P played a more important role in the 16 extractions.

Conclusions

Ca8-P was the greatest potential pool for P desorption after Ca2-P was depleted. P desorption capacity was significantly linearly related to initial Olsen-P (P?<?0.01). Different fertilizer use strategies were developed based on P desorption capacity for soils with different initial Olsen-P levels. The present study provided basic data on how to reduce effectively the application amount of chemical P fertilizer.

  相似文献   

16.
采用室内培养和化学分析的方法研究了几种有机酸对石灰性潮土无机磷形态转化的影响。结果表明,1)石灰性潮土中磷素主要以有效性很低的磷酸盐(Ca10-P等)形式存在,而有效性较高的磷酸盐(Ca8-P等)含量较少,Ca2-P就更少。2)不同磷源施入土壤后,无机磷总量相应增加。磷酸二氢钾与磷酸二钙主要向Ca8-P、Al-P等有效性相对较差的磷素形态转化,磷酸八钙、氟磷灰石、磷酸铁、磷酸铝等有效性较差的磷源,在较短的时期内主要以自身的形态存在。3)施加各种有机酸可以不同程度地降低土壤中Fe-P、Al-P和Ca10-P含量,增加Ca2-P、Ca8-P和O-P含量,总的趋势是促进土壤中植物难以利用的无机磷形态向植物可以利用的形态转化。这种促进能力因有机酸种类和性质的不同而不同,其作用大小顺序为草酸柠檬酸酒石酸。  相似文献   

17.
为探究在全球气候变化敏感区的干旱区高寒湿地上,氮添加对土壤无机磷形态的影响。在保护良好的巴音布鲁克高寒湿地沼泽(S)、沼泽草甸(SM)和草甸(M)布设野外原位试验,依据巴音布鲁克草原氮沉降量,设置0(CK),8(N1),16(N2) kg·N/(hm2·a)的施氮量,研究短期氮添加对高寒湿地土壤无机磷形态的影响。结果表明:(1)高寒湿地土壤全磷含量平均为1.09 g/kg,总无机磷平均为492.71 mg/kg,而总无机磷平均占全磷的45.67%。(2)3种湿地类型土壤无机磷主要以Ca—P形态存在,在Ca—P中以Ca10—P为主,占无机磷含量的50.27%~64.69%。S区土壤Al—P、Fe—P含量显著高于SM和M区,SM区Ca2—P、Ca8—P、O—P含量显著高于S和M区,M区土壤Ca10—P含量显著高于S和SM区。(3)氮添加显著影响高寒湿地土壤各形态无机磷的含量,氮添加下,S和SM区土壤Al—P含量较CK显著增加了9.92%~17.35%,而Ca8—P含量显著降低3.18%~9.36%。[JP]S和M区土壤Fe—P含量显著降低了3.18%~9.36%,S区土壤Ca2—P含量显著降低了10.31%。氮添加下3种湿地类型土壤O—P含量均显著增加,较CK显著增加21.83%~25.94%。(4)土壤pH、有机碳、碱解氮和速效钾均是影响无机磷形态的重要因子。不同湿地类型土壤无机磷形态含量存在显著差异,氮添加显著改变了土壤各无机磷形态含量,主要是通过增加土壤中难利用无机磷(O—P)含量,使高寒湿地土壤的供磷潜力降低。研究结果有助于预测未来氮沉降持续增加背景下全球高寒湿地土壤无机磷形态的变化趋势。  相似文献   

18.
The effects of plant vegetation on phosphorus(P) speciation, pH, total carbon concentration, total nitrogen concentration, and alkaline phosphatase activities were investigated to explore the P uptake strategy of plants in low-P soil and to determine the nutrient stoichiometric ratio changes in the rhizosphere of plants(Imperata cylindrica, Miscanthus floridulus, Zoysia sinica, Artemisia lavandulaefolia, Indigofera pseudotinctoria, and Conyza canadensis) which had grown for approximately 15 years in copper mine tailings, East China. The results showed that the average pH values in the rhizosphere decreased by 0.06–1.37 compared with those in the non-rhizosphere. The alkaline phosphatase activities of the rhizosphere were significantly higher than those in the non-rhizosphere.The mean concentrations of aluminum(Al)-and iron(Fe)-bound P and Ca_2-P(CaHPO_4) in the rhizosphere of all plants were 5.4% to 87.7%, 49.2% to 214.2%, and 86.6% to 147.6% higher than those in the non-rhizosphere, respectively. Except for Ca_8-P(Ca_8H_2(PO_4)_6)and Ca_(10)-P(Ca_(10)(PO_4)_6(OH)_2) in the rhizosphere, all kinds of inorganic P forms were negatively correlated with pH. Significant correlation was also observed among the concentrations of dominant forms of inorganic P, C, and N and alkaline phosphatase activities in the rhizosphere. Among the studied species, I. pseudotinctoria showed the most significant effect on enhancing soil available P concentration. The stoichiometric ratios of C:P and N:P were apparently higher in the rhizosphere than the non-rhizosphere, whereas these ratios were far below the ratios commonly observed in Chinese soils. These results indicated that the plant growth effectively affected P fractions possibly by changing pH, C and N concentrations, and alkaline phosphatase activity, in the rhizosphere in copper mine tailings.  相似文献   

19.
制种玉米连作恒量施磷对灌漠土与潮土中磷素利用的影响   总被引：2，自引：0，他引：2  
[目的]研究恒量外源磷施用对玉米种子生产的影响,为合理施磷提供依据。[方法]通过大田定位与实验室分析相结合,选用河西走廊石灰性潮土及灌漠土定位施肥。[结果]制种玉米连作8a,恒量磷二铵525kg/(hm^2·a)施用,除无机态二钙磷(Ca_2-P)外,2种不同土类总磷(T-P)、速效性磷(Av-P)、总无机磷(T-IP)、总有机磷(T-OP),以及其他各分级无机、有机磷组分均显著增加。无机磷占全磷总量65.2%~70.2%,有机磷占全磷总量6.5%~11.4%。无机磷中十钙磷(Ca10-P)>八钙磷(Ca8-P)>铝磷(Al-P)>铁磷(Fe-P)>闭蓄态磷(O-P)。有机磷中活性有机磷(MLO-P)>高稳性(HRO-P)>中稳性有机磷(MROP)>活性有机磷(LO-P)。随连作年限增加,灌漠土Ca10-P在连作第5a达到最大,Al-P,O-P均持续增加;潮土Ca10-P持续增加,Fe-P,O-P在连作第5a达到最大,磷增加量为3.94%~37.28%。0—60cm土层,两种土类无机磷各组分含量均呈现由表层至下层递减特点,但不同分级磷在不同土层所占比例不同,Ca10-P,Al-P,O-P,MRO-P底聚,Ca_2-P,HRO-P表聚,制种玉米连作生产8a,磷肥最大表观利用率为4.89%,磷素活化系数<2%,外源磷肥以174.3kg/(hm^2·a)残余在土壤中。[结论]制种玉米连作,总磷转化率低,磷素移动缓慢,大部分以溶解性较低的磷素形态在土壤表层积累,但随连作年限增加,土壤对磷素的固持及转化率下降,表现底聚趋势,对生态环境健康存在极大风险,应减量或停止施磷。潮土磷肥施用应采取更加合理措施。  相似文献   

20.
不同水分和添加物料对石灰性土壤无机磷形态转化的影响   总被引：7，自引：2，他引：7  
利用轻粘质土壤 ,模拟石灰性土壤中不同的组分因素进行室内培养试验。结果表明 ,水溶性磷肥施入土壤后很快向其它无机磷形态转化 ,主要转化为Fe-P ,其次是Ca2-P、Ca8-P和Al-P ,而很少转化为O-P和Ca10-P。其转化规律受不同培养组分因素的影响。较低的土壤水分含量 (200g/kg)利于Ca8-P、Al-P向Fe P和Ca10-P的转化 ,过高的水分含量 (200g/kg)有利于Ca10-P的活化与Fe-P的大量生成 ;不同量CaCO3加入促进了Fe-P、Al-P以及Ca2-P向Ca8-P、Ca10-P方向转化 ;秸杆、腐植酸的加入增加了各形态无机磷量以及无机磷总量。随培养时间的延长 ,Al-P、Fe-P等形态的磷量减少 ,Ca8-P、Ca10-P形态的量增加。不同量秸杆以及腐植酸的加入不同程度地降低了速效磷下降的幅度 ,提高了土壤速效磷水平。  相似文献   

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