几种黄土母质土壤磷吸附特性及缓冲性能的初步研究

黄绵土、黑土娄土和土娄土是西北特别是陕西的主要农业土壤。它们发育于黄土母质 ,但质地等性质有显著不同[1] 。根据第二次全国土壤普查资料[1] 和近几年的肥料试验 ,这些土壤有效磷低 ,多属缺磷土壤。施用磷肥的效果取决于土壤有效磷的数量 ,有效磷的数量则受控于土壤磷的吸附反应。土壤磷的等温吸附把土壤溶液磷和土壤固相磷联系了起来 ,是研究植物需磷与土壤供磷关系的有效方法[2 ,3] 。虽然土壤磷等温吸附模式有多种 ,但许多研究表明 ,Lang-muir方程比其它模型优越。因为 Langmuir方程通常具有最好的相关性 ,并且由 Langmuir方程可以…     

水滑石改性生物炭有效提高设施菜田土壤磷的吸附性能

【目的】设施菜田土壤磷素高量累积、磷迁移风险高。水滑石改性生物炭是很好的阴离子吸附材料,探究不同原材料制备的水滑石改性生物炭对高磷设施菜田土壤磷吸附性能的影响,为高磷设施菜田合理利用改性生物炭、降低磷素损失风险提供科学依据。【方法】采用500℃下限氧热解法制备竹炭(BB)、玉米秸秆炭(MB)和猪粪炭(PB)样品,利用共沉淀法将Zn/Fe水滑石(Zn/Fe-LDHs)分别负载在3个生物炭表面,得到水滑石改性竹炭(LDH-BB)、水滑石改性玉米秸秆炭(LDH-MB)和水滑石改性猪粪炭(LDH-PB)。以6个生物炭样品为试材进行土壤磷吸附–解吸实验和土柱淋溶实验,以不添加生物炭处理为对照。磷吸附–解吸实验利用Langmuir和Freundlich方程拟合吸附数据,并测定了土炭混合物的磷解吸量。土柱淋溶实验测定了淋溶液体积、pH及不同形态磷含量。【结果】水滑石改性生物炭的Zn、Fe元素含量、O/C和(O+N)/C原子比提高,pH、C、N和P元素含量降低。改性后生物炭表面出现不规则层状附着物,比表面积增加,其大小依次为LDHBB>LDH-PB>LDH-MB>BB>MB&g...     

土壤中磷吸附的能量特征

应用同位素 ( 32 P)示踪法 ,对陕西省四种土壤中磷素运移动力学特征进行研究得出 :( 1 )提出溶质运移动力学研究命题具有必要性和实际意义 ;有助于进一步对溶质运移机理进行探讨 ;( 2 )将过渡态理论移植到磷运移动力学中加以应用是可行的 ,所求出的磷运移活化能 (E y)和假热力学参数———活化焓(△H y)、活化自由能 (△G y)和活化熵 (△S y)可从不同的角度反映出磷运移过程中的能量变化 ,本文拟就这方面作一探讨性研究     

Chemical equilibrations with soil buffer systems as bases for future soil testing programs

Abstract

The soil has mechanisms which serve as buffers or ionic reservoirs which remove nutrient ions from and return them to the soil solution and thus regulate their availabilities to higher plants. Yet relative amounts of each type of cation‐exchange bond are evidently so different from soil to soil that basic cation saturation ratios per se seem unimportant to the well‐being of a crop. Indeed, it appears that instead we should concentrate on sufficiency levels of each basic cation.

Since the above‐mentioned mechanisms buffer the soil available P and K levels as well as pH level, we have developed alternative usages for existing soil tests which seem quite promising as bases for improving the accuracy of lime, and P and K fertilizer recommendations for obtaining near‐maximum yields of crops.     

中国太湖环境土壤磷测试与磷释放

A microtiter plate assay (MPA) for soluble reactive phosphorus (SRP) was applied to samples in overlying water and pore water as well as in three forms of environmental soil test phosphorus (P) types: water soluble phosphorus (WSP), diluted calcium chloride extractable phosphorus (PCaCl2), and Olsen-P in the sediments of Taihu Lake, China, where potential P release in response to pH was analyzed. MPA for rapid P analysis was shown to be promising when applied on samples of natural water and sediment extracts. Concentrations of WSP and PCaCl2 in the sediments were much lower than those of Olsen-P. Olsen-P levels in the littoral sediments along the north coast of Meiliang Bay in Taihu Lake (80 to 140 mg kg^-1) were much higher than those in the mouth of the bay (less than 50 mg kg^-1). The risk of P release in the mouth area of Meiliang Bay was lower than that in the north littoral zone with a risk of sediment P release induced by pH increases.     

Use of phosphorus vectors to monitor changes in soil phosphorus

Abstract

A study was conducted to evaluate the use of P vectors to predict the amount of P required on a yearly basis to maintain a constant solution‐solid phase P relationship in an irrigated calcareous and a dryland acid soil. Irrigated potato‐spring barley and dryland spring pea spring‐barley crop rotations established at the two locations. Mono‐calcium phosphate (0–45–0) was applied annually at five levels, ranging from 0–4 times estimated crop removal. Phosphorus vectors were determined on soil samples by equilibration with standard P solutions. Yields tended to increase with added P on the calcareous soil; however, significant responses were not recorded at either location. Consequently, critical P vectors were not established. A constant solution‐solid phase P relationship was maintained by addition of P equal to that removed by the crop on the calcareous soil. A constant solution‐solid phase P relationship was not maintained on the acid soil.     

潮土累积磷的供磷能力及其有效磷消耗特征

[目的]长期过量施肥极大地提升了土壤中磷的累积量.研究土壤累积磷的有效性及其消耗特征,可为发掘土壤中的磷资源,保持土壤磷肥力的可持续性提供理论基础.[方法]依托"国家潮土肥力与肥料效益长期监测站"26年的长期定位试验,从中选取5个磷地力水平地块,其土壤基础Olsen-P含量分别为1.2、14.3、27.6、55.4、7...     

Soil phosphorus testing: 2. Assessment of a rotary blade soil sampler for collecting soil samples to measure soil test phosphorus

Abstract

In Western Australia soil samples to measure soil‐test phosphorus (P) are collected November to March when soils are usually dry. Most of the soils are hard‐setting when dry and it is difficult to penetrate and collect soil samples to 10 cm using the traditional sampler, which is a 2.5 cm diameter tube that is pushed into the soil by foot. Farmers collect too few soil samples at shallow depths to measure soil‐test P. In Part 1 of this paper, it was shown that soil‐test P can vary markedly for individual soil samples collected from uniform areas in paddocks. Consequently, an adequate number of soil samples needs to be collected and bulked from defined areas to measure soil‐test P. Phopshorus accumulates near the top of the soil of (i) pastures since P fertilisers are applied to the surface of pastures, and (ii) crops sown by minimum (conservation) tillage. Crops are increasingly being sown using conservation tillage methods. Collecting too few soil samples to a shallow depth can result in large errors when estimating the current P status of soils and determining optimum fertiliser application levels. A new rotating blade method of collecting soil samples to the standard 10 cm depth for measuring soil‐test P was compared with the traditional sampler. The new sampler successfully penetrated hard‐setting soils to the standard depth and the soil samples it collected produced similar soil‐test P as the traditional sampler. Consequently, the same soil‐test P calibrations determined using the traditional sampler can also be used for the new sampler. The new sampler is, therefore, recommended for collecting soil samples to measure soil‐test P. It should have application wherever hard‐setting soils pose a problem for soil P testing.     

长期不同施肥对黄壤磷素吸附–解吸特性的影响

[目的]磷吸附–解吸特性对土壤磷素有效性和环境流失风险有重要影响.研究长期不同施肥对黄壤旱地磷吸附–解吸特性的影响,可为黄壤区合理施用磷肥提供理论依据.[方法]供试黄壤肥力长期定位试验位于贵阳,始于1995年.设有对照(CK)、施氮钾肥(NK)、施氮磷钾肥(NPK)、单施有机肥(M)和有机肥化肥配施(MNPK)5个处理...     

施硅对水稻土磷素吸附与解吸特性的影响研究

研究了水稻土中施Si对P吸附与解吸特性的影响。结果表明 ,由于土壤中Si、P存在着竞争性吸附 ,当Si施入土壤时 ,它必然占据一部分Si、P共用的吸附点位 ,降低了土壤中P的吸附量。施Si对P解吸量的影响比较复杂 ,在低P浓度 (10、20、30mg/kg)时 ,施Si增加了P的解吸量 ;在高磷浓度 (40mg/kg)时 ,施Si后P的解吸量变化不大 ,而P浓度为 50mg/kg时 ,P的解吸量随Si的施加呈下降趋势。表明Si减少P吸附量的同时 ,也由于降低了土壤对P的吸附结合能 ,而增加了易解吸P的含量。施Si明显的提高了土壤P的解吸率     

Use of a microtitre plate reader in soil phosphorus analysis

Abstract

A technique is described for using microtitre plates and plate reader in soil phosphorus analysis. The molybdate‐vanadate method of phosphorus analysis was modified to use a reduced volume of reagents and each sample was read at 405 nm instead of 420 nm. Using standard microtitre plates instead of test tubes, the volume of reagent was reduced 20 X and as many as 96 samples could be read in a total of two minutes.     

Use of a microtitre plate reader in soil phosphorus analysis

Abstract

A technique is described for using microtitre plates and plate reader in soil phosphorus analysis. The molybdate‐vanadate method of phosphorus analysis was modified to use a reduced volume of reagents and each sample was read at 405 nm instead of 420 nm. Using standard microtitre plates instead of test tubes, the volume of reagent was reduced 20 X and as many as 96 samples could be read in a total of two minutes.     

施磷对水稻土硅素吸附与解吸特性的影响

研究了水稻土中施磷 (P)对硅 (Si)吸附与解吸特性的影响。结果表明 ,由于土壤中Si、P元素化学性质和结构相似 ,存在着竞争性吸附 ,施P降低了土壤中Si的吸附量 ,同时增加了土壤Si的解吸量 ,提高土壤Si的解吸率。表明P在降低土壤Si吸附量的同时 ,也由于降低了土壤对Si的吸附结合能 ,从而增加了Si的解吸量。P的存在对Si的吸咐具有一种外推作用。连续解吸试验进一步证实了上述的观点。     

玉米秸秆还田及施磷量对黑土磷吸附与解吸特性的影响

以探究松嫩平原玉米连作条件下,秸秆还田与施磷量互作对黑土磷吸附与解吸特性的影响为目的。该试验采取二因素裂区试验设计,主因素为玉米秸秆还田方式,分别为秸秆不还田(S0)、秸秆翻埋还田(S1)和秸秆焚烧还田(S2);副因素为施磷水平,分别为0(P0)、34.50(P1)、69(P2)、103.50(P3)kg/hm~2(P_2O_5)。结果表明:1)Langmuir等温吸附方程最适合拟合黑土对磷的吸附特征。2)秸秆还田与施磷量均显著影响黑土对磷的吸附与解吸特性,且两者互作效应显著。在相同秸秆还田方式下,随着施磷量的增加,土壤对磷的吸附能力均逐渐降低,而土壤中磷的解吸量和解吸率均逐渐增加,其中以S0条件下差异最大,S2条件下次之,S1条件下差异最小。在相同施磷水平下,与S0处理相比,S1和S2均能降低土壤对磷的吸附能力,增加土壤中磷的解吸量和解吸率,其中以不施磷肥(P0)处理下差异最大,而在施高磷(P3)处理下差异不显著,此外,S1与S2在各施磷水平下差异均不显著。3)不同施磷处理下的标准需磷量(standardPrequirement,SPR)为71.02～91.67 kg/hm~2,其中以S1P2处理的SPR(73.58 kg/hm~2)与P2施磷水平(69 kg/hm~2)最相近,是松嫩平原黑土区较为适宜的施磷方式。     

Environmental risks of increasing phosphorus addition in relation to soil sorption capacity

Phosphorus content of soil profiles, interstitial water, and shallow groundwater was determined in a semiurban region of Buenos Aires city in order to examine phosphorus leaching. Soils from different places and position in the slope were characterized and analysed for their P sorption–desorption capacities in order to understand transport processes and to assess potential environmental risks. Adsorption increases with depth and decreases with increasing additions of phosphorous. Interstitial water at 0.6 m depth showed greater P concentrations than shallow groundwater (9 to 30 m depth) in accordance with the importance of clays for P adsorption.     

国标土样在土壤有效磷含量检测和质控中的应用

定期使用有证标准物质可验证试验数据准确性,以发现操作者、仪器、材料、方法、环境中出现的超限现象,能有效地监控试验过程,提高检测质量。本试验研究了国标土壤对土壤有效磷测定数据进行控制,保证试验数据可靠性。结果表明,除2010月4月27日结果不稳外,其余测定值在16.4～19.8 mg/kg,相对标准偏差(RSD)为6.20%;质控图有93%试验点在上下辅助线内,未发现连续7个点位于中心线同一侧,质控图可靠;同时期相比2011年上半年测得国标土壤有效磷含量高于2010年,数值多稳定在18.3 mg/kg以上,精确度和准确度均以2011年较好。     

Samples disturbance overestimates phosphorus adsorption capacity in soils under long-term application of pig slurry

Grinding soil for analysis causes the destruction of aggregates and may expose adsorption sites that would not be available for adsorption in the soil with preserved structure. The study aimed to evaluate the adsorption of P in three soils with and without preserved structure, submitted to pig slurry (PS) application for a long time. Three soils (Acrisol, Ferralssol and Nitisol) with contrasting textures and P contents, with and without PS were selected and samples were collected with and without preserved structure in the 0–10 and 10–20 cm layers. The undisturbed soil columns were submitted to continuous flow, for 10–24 h, of 300 mg L^?1 P solution and, at regular intervals, aliquots of the resulting solution were collected and the P content was determined. These data were adjusted exponential models to estimate the maximum adsorption of P. The maximum capacity of P adsorption of the soils were 1.4 to 14 times higher in the milled soil samples, making it clear that the destruction of the soil structure, and consequently the porosity and the preferential paths of percolation of the liquids in the soil leads to an overestimation of the soil capacity to adsorb the P applied to the surface.     

Use of Ion exchange membranes in routine soil testing

Abstract

We developed and assessed a method for simultaneous extraction of plant available nitrogen, phosphorus, sulfur and potassium using anion and cation exchange membranes (ACEM). The technique was found to be highly suitable for routine soil testing due to its simplicity, rapidness and accuracy. The study compared the amount of nutrients extracted by ACEM with conventional chemical‐based extractants for P and K (0.5M NaHCO₃) and N and S (0.001M CaCl₂) for 135 soil samples representing a wide range of soil types in Western Canada. The nutrient availability predicted by ACEM was significantly correlated with the conventional methods. The correlation was not affected by the two different shaking times tested (one hour and 15 minutes), suggesting that extraction times as short as 15 minutes could be used in ACEM extraction. To evaluate the relative ability of ACEM and the conventional tests to predict actual nutrient availability to plants, canola plants were grown on soils in the growth chamber and actual plant uptake was compared to test‐predicted nutrient availability. Phosphorus and potassium uptake by canola plants was more closely correlated with ACEM extractable P and K (r²= 0.84*** and 0.54***) than with 0.5M NaHCO₃ P and K (r²= 0.70*** and 0.37***). Also, nitrogen and sulfur uptake by canola plants was significantly correlated with ACEM extractable‐NO₃ and ‐SO₄ (r² = 0.60*** and 0.70***) and with CaCl₂ extractable‐NC₃ and ‐SO₄ (r² = 0.57*** and 0.61***). Availability of all four macronutrients can be assessed in a single ACEM extraction. The higher correlation with plant uptake suggests that ACEM is a better index of macronutrient availability than conventional methods. The ACEM soil test could be readily adopted in routine soil analysis because of low cost and simplicity as well as its consistency over a wide range of soil types.     

长期施磷黑土中磷的吸附–解吸特征及其影响因素

  【目的】  比较长期不施磷与施磷黑土对外源磷的吸附–解吸特征,为黑土区磷素管理提供理论基础。  【方法】  供试黑土长期定位试验位于吉林省公主岭市,始于1990年。2018年选择其中不施肥(CK),施氮钾肥(NK),施氮磷钾肥(NPK)和氮磷钾+有机肥(NPK+M) 4个处理小区,采集0—20、20—40和40—60 cm土层的土壤样品,分析了土壤理化性质,采用恒温平衡法测定了土壤磷的吸附–解吸特征,并由此计算得到磷最大吸附量(Q_m)、吸附亲和力常数(K_Q)、最大缓冲容量(MBC)、磷吸附饱和度(DPS)、最大解吸量(D_m)和解吸率(D_r)。  【结果】  随着平衡溶液中磷浓度的增加,磷的吸附量与解吸量均呈先快速增加后逐渐趋于平衡的过程。与不施磷处理(CK和NK)土壤相比,施磷处理(NPK、NPK+M)减少了磷的吸附量,增加了磷的解吸量。与不施磷处理相比,施磷处理在0—60 cm剖面上的Q_m和MBC值分别降低了4.94%～63.46%和15.90%～75.18%,D_r值增加了8.52%～474.0%,以NPK+M处理变化量最大。施磷处理比不施磷处理在0—60 cm土壤剖面上全磷和有机质含量分别增加了34.40%～145.5%和12.77%～50.07%,游离态铁铝氧化物(Fe_d+Al_d)含量降低了5.14%～11.35%。冗余分析表明,不施磷处理土壤的有机质、Fe_d+Al_d和全磷,以及施磷处理中的Fe_d+Al_d、络合态铁铝氧化物(Fe_p+Al_p)、pH和有机质是影响磷吸附解吸特征参数的主要土壤因子,分别解释了不施磷和施磷处理全部变异的77.59%和90.62%。土壤有效磷(Olsen-P)与磷吸附饱和度(DPS)相关关系表明,所研究的黑土DPS环境界限值为8%左右,NPK+M处理中3个土层的DPS_M-P值(由Mehlich-3 浸提的磷、铁和铝计算)为7.77%～25.96%,DPS_O-P值(由Olsen-P和Q_m计算)为17.24%～24.75%,均高于此环境界限值,具有磷素流失的风险。  【结论】  长期施磷降低了黑土对外源磷的吸附量,增加了磷解吸量。长期不施磷肥,土壤对磷的吸附和解吸主要受有机质、游离态铁铝氧化物的影响。而长期施肥,特别是有机肥与化肥配合处理,土壤中游离态和络合态铁铝氧化物、有机质及pH是影响磷吸附解吸特征的主要因素。     

Soil phosphorus testing: 1. studies on spatial variation of colwell soil test phosphorus

Abstract

Spatial variation of soil test phosphorus (P) was studied by measuring soil‐test P for individual soil samples collected from uniform areas in south‐western Australia. The soil samples were collected using standard 10 cm deep by 2.5 cm diameter samplers. The Colwell alkaline bicarbonate soil test, the standard reagent adopted in Western Australia, was used. There were two parts to this study. In Part 1, 36 individual soil samples were collected on 20 m by 20 m grids within a uniform 100 m by 100 m area in paddocks on 16 different lateritic soil types. Superphosphate had been applied each previous year, using normal farmer practices, for either nine years at two sites or >20 years at the other sites. For pastures, fertiliser is usually applied to the surface. For crops, it is drilled with the seed at about 5 cm depth. In Part 2, 10 to 20 individual soil samples were collected at random locations within experimental plots (either 2 or 4.8 m wide by 30 m long) of five long‐term field experiments that were treated once only with different amounts of superphosphate applied from two to eight years previously. The P was applied to the soil surface and either incorporated through the soil with a rotary hoe or when sowing crops at 5 cm depth with tined implements, or the P was placed at 5 cm depth in bands that were 180 mm apart and the soil was not disturbed thereafter. For each site in Part 1, or each plot of each experiment in Part 2, soil‐test P for the individual soil samples varied, often markedly. Coefficient of variation was large. It was up to 56% for Part 1. For Part 2, it was up to 82% when P was incorporated into the topsoil, and up to 210% when P was banded in the soil. Spatial variation of soil‐test P is attributed to natural variation of soil physical, chemical, and mineralogical properties. Some of the variation may also be due to heterogenous mixing through the topsoil of fertiliser P applied in recent years. Soil‐test P is usually larger for recently applied fertiliser P.