首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Reports of sugarcane yield responses to silicon (Si), coupled with mounting evidence that elevated crop Si levels reduce both biotic and abiotic stresses, account for the interest in the Si nutrition of this crop. In terms of managing Si supplies to sugarcane in South Africa, uncertainties exist regarding, first, the reserves of plant-available Si in soils, and second, the reliability of soil-test methods for predicting Si availability. In this study, extractable Si was measured in 112 soils collected from sugarcane-producing fields in South Africa. Soils were selected on the basis of dominant soil types and included Inceptisols, Alfisols, Mollisols, Vertisols, Oxisols, Entisols, and Ultisols, varying widely in chemical properties, texture, and extent of weathering. Extractants employed were 0.01 M calcium chloride (CaCl2) and 0.02 N sulfuric acid (H2SO4). Silicon extracted with 0.02 N H2SO4 ranged from 2 to 293 mg kg?1, whereas with 0.01 M CaCl2 the range was 5 to 123 mg kg?1. With both extractants, extractable Si decreased significantly with decreasing pH, exchangeable calcium (Ca), and total cations. In soils with potassium chloride (KCl)–extractable Al+H levels of greater than 0.5 cmolcL?1, extractable Si levels were consistently low, suggesting that soluble Al is implicated in reducing plant-available Si levels. Extractable Si levels were not related to the Bache and Williams P-sorption indices of soils. In the second part of the investigation, sugarcane leaf Si concentrations from 28 sites were related to soil extractable Si levels. The CaCl2 soil test proved markedly superior to H2SO4 as a predictive test for leaf Si levels.  相似文献   

2.
Abstract

Eighty four soil samples collected from southeastern Norway were analyzed for Cd by extraction with NH4OAc, DTPA, NH4OAc-EDTA, NH4NO3, HCl and CaCl2. The total Cd, pH, exchangeable K and Ca, dithionite-extractable Mn, available P and fine sand (0.2–0.02 mm) contents were the principal factors related to the extractable Cd, with some inter-extractant variations. Cadmium extracted by NH4NO3, NH4OAc, HCl and CaCl2 decreased with increasing soil pH, but the Cd extracted by all the extractants increased with increasing total Cd, exchangeable K and Ca, available P, and Mn-oxide contents in the soils. The Cd concentrations in plants were significantly related to the extractable Cd, exchangeable Ca and Mg, pH, Mn-oxides and organic matter content.  相似文献   

3.
Abstract

A relatively small range between deficiency and toxic limits of boron (B) necessitates precise evaluation of the availability of extractable boron before applying B in deficient soils. Keeping this in view, laboratory and greenhouse experiments were conducted to assess the availability of native B in soils. For this purpose, 25 acid soils with diverse properties and varying hot water extractable B content, were selected from lateritic and alluvial tracts of Southern West Bengal. A greenhouse pot experiment with four rates of B (0, 0.5, 1.0, and 2.0 mg kg‐1) was conducted in completely randomized design to study the response of soybean (Glycine max L.) to native and applied B in all 25 soils. The suitability of nine extractants for determining available soil B was assessed by correlating the amount of extractable B in untreated soils with Bray's percent yield, uptake, and tissue B concentration of soybean plants. Optimization of salicylic acid concentration is described and the advantages of this extractant are discussed. The interference of amethyst color (produced by iron and salicylic acid) with the colorimetric estimation of B is studied. Hot CaCl2 was found to be the most suitable extractant for the determination of available B in these soils, followed by hot water, salicylic acid, and ammonium acetate. However, salicylic acid appeared to be the most efficient extractant for routine soil analysis for available B, where a large number of samples are analyzed. The critical values in respect to sufficiency of extractable B for soybean plants were 0.51 for hot water, 0.61 for hot CaCl2, 0.27 for ammonium acetate and 0.45 mg kg‐1 for salicylic acid. The critical B concentration in soybean plants was 18 mg kg‐1 on dry weight basis. Multiple regression equations relating soil properties to native soil B extracted by various extractante were developed. It was observed that organic carbon and clay contributed positively to B extracted by hot water, hot CaCl2, and ammonium acetate, while salicylic acid extractable B showed positive relationships with cation exchange capacity (CEC) and clay. The CEC and Fe2O3 were found to have positive influence on tartaric acid extractable B. Implications of the influences of soil properties on the extractable B content of soils are discussed.  相似文献   

4.
Abstract

Exchangeable potassium (K) is the readily available form but when this pool is not sufficient, plants must be supplied from less labile forms of this nutrient. In this study, the contribution of nonexchangeable K to plant nutrition and the uptake rate of this nutrient in successive harvests were investigated. A greenhouse experiment was performed sowing annual ryegrass (Lolium multiflorum sp) on four agricultural soils with a wide range in exchangeable K concentration. The soils were a) Acuic Argiudol, b) Entic Hapludol, c) Typic Argiudol (Ordoñez and M. Juarez). Five harvests were conducted resowing after each one. Soil K extractable with 0.01 M CaCl2, exchangeable and nonexchangeable K was determined. Plant analyses were conducted to asses total K. The highest nonexchangeable K contribution to the total K uptaken by plants (in percentage) was observed in the Acuic Argiudol soil due to its low exchangeable K concentration. For the Typic Argiudol soils, this contribution varied according to exchangeable K concentration (Ordoñez soil) or according to the clay content and the mineralogy (M. Juarez). For all soils, the highest plant uptake rate was for the first harvests corresponding to the uptake of soluble K and the K located in the most labile positions in the exchange complex. This fact is confirmed by the high correlation obtained between the uptake rate and the amount of K extracted with CaCl2 (p<0.05). For subsequent harvests, a progressive decrease of K uptake rate was observed. In the fifth harvest plant uptake mostly depends on the nonexchangeable K concentration (p<0.05). The Acuic Argiudol soil, presents a special behavior ? given that it reaches the minimum rate in the third harvest due to the low concentration of all K forms of this soil.  相似文献   

5.
Behaviour of heavy metals in soils. 1. Heavy metal mobility 158 soil samples with widely varying composition were analysed for their total, EDTA, DTPA and CaCl2 extractable contents of Cd, Zn, Mn, Cu and Pb. By means of single and multiple regressions the relations between the different heavy metal fractions and the pH, organic carbon and clay content were considered. The correlations between the total, EDTA and DTPA extractable contents are very close, whereas the CaCl2 extractable contents are not or only weakly correlated with these fractions. According to these statistical results the former fractions are considered to be the total quantity (total content) and the reactive quantity (EDTA and DTPA extractable contents) of the heavy metals, whereas the CaCl2 extractable fraction represents the mobile fraction of the heavy metals in soils. The multiple regressions show that the mobile content of heavy metals is closely correlated with each of the quantity fractions and with soil pH. In the same way the proportion of the mobile fraction (in %) of the total, EDTA and DTPA extractable heavy metal content of the soil samples is closely related to the soil pH. Hereby the proportion of the mobile content of the various elements increases in the pH range 6,5 - 3 below element-specific threshold pH values (in brackets) in the order Cd (6,5) > Mn (5,7) > Zn (5,3) > Cu (4,5) > Pb (3,5). In the pH range 6,5 - 7,5 mainly Cu and to a lesser degree also Pb show an increasing mobility due to the influence of soluble organic substances.  相似文献   

6.
Different forms of manganese (Mn) were investigated, including total, diethylenetriamine penta-acetic acid (DTPA) extractable, soil solution plus exchangeable (Mn), Mn adsorbed onto inorganic sites, Mn bound by organic sites, and Mn adsorbed onto oxide surfaces, from four soil taxonomic orders in northwestern India. The total Mn content was 200–950 mg kg?1, DTPA-extractable Mn content was 0.60–5.80 mg kg?1, soil solution plus exchangeable Mn content was 0.02–0.80 mg kg?1, Mn adsorbed onto inorganic sites was 2.46–90 mg kg?1, and Mc adsorbed onto oxide surfaces was 6.0–225.0 mg kg?1. Irrespective of the different fractions of Mn their content was generally greater in the fine-textured Alfisols and Inceptisols than in coarse-textured Entisols and Aridisols. The proportion of the Mn fractions extracted from the soil was in the order as follows: Adsorbed onto oxide surfaces > adsorbed onto inorganic site > organically bound > DTPA > soil solution + exchangeable. Based on coefficient of correlation, the soil solution plus exchangeable Mn, held onto organic site and oxide surface (amorphous) and DTPA-extractable Mn, increased with increase in organic carbon of the soil. The two forms, adsorbed onto inorganic site (crystalline) and DTPA extractable, along with organic carbon, increased with increase in clay content of the soil. DTPA-Mn and Mn adsorbed onto oxide surfaces and held on organic site decreased with increased with an increase in calcium carbonate and pH. Total Mn was strongly correlated with organic carbon and clay content of soil. Among the forms, Mn held on the organic site, water soluble + exchangeable and adsorbed onto oxide surface were positively correlated with DTPA-extractable Mn. DTPA-extractable Mn seems to be a good index of Mn availability in soils and this form is helpful for correction of Mn deficiency in the soils of the region. The uptake of Mn was greater in fine-textured Inceptisols and Alfisols than in coarse-textured Entisols and Aridisols. Among the different forms only DTPA-extractable Mn was positively correlated with total uptake of Mn. Among soil properties Mn uptake was only significantly affected by pH of the soil.  相似文献   

7.
Abstract

Whether a tropical soil should be limed or not for a particular crop is strongly dependent on the levels of soil aluminum (Al) which can be determined with soil tests. Soil pH is used to predict whether lime is needed in less‐weathered soils, although some evidence indicates a soil Al test would be more accurate. The objectives of this study were to determine and to compare the accuracies of four soil tests to separate soils requiring lime from those that do not, and to determine the cause of acid‐soil injury to soybean [Glycine max (L.) Merr.]. Soybean was grown in the greenhouse on four surface soils representing the major land resource areas of Louisiana and were amended with eight rates of lime, yields determined, and soils analyzed for soil pH, extractable Al, CaCl2‐extractable Al, CaCl2‐extractable manganese (Mn), and Al saturation. Acid‐soil injury in soybean grown on the Litro clay and Stough fsl was probably caused by soil‐Al effects while low soil calcium (Ca) and high soil Mn was likely responsible for lower yields from the Mahan fsl. Leaf Ca from the limed Mahan‐soil treatment was 5‐fold greater and leaf‐Mn 7‐fold less than control levels. Regression analyses’ R2 values were similar for all soil tests except for CaCl2‐extractable Mn, which was lower. Soil tests were compared across soil type by selecting treatments that had the same 85% relative yield. Using this data subset, there was no difference in the soil pH among the four soils, while there were significant differences among soils for all other soil test measurements indicating the superiority of soil pH for identifying acid‐soil injury. Critical test values were 5.1 soil pH, 30 mg kg‐1 extractable Al, 7% Al saturation, 0.7 mg‐kg‐1 CaCl2‐extractable Al, and 9 mg‐kg‐1 CaCl2‐extractable Mn.  相似文献   

8.
The more labile forms of aluminium in a range of soils from areas of permanent grassland were determined with a number of selective extractants. The amounts of exchangeable A1 extracted with molar KCl were dependent upon pH, while the amounts exchangeable with 0.3 M LaCl3, although much greater, were not well correlated with pH. There were good correlations between soil organic C content and A1 extracted by (i) 0.5 M EDTA and (ii) 0.1 M potassium pyrophosphate. Pyrophosphate extracted greater amounts than any of the other extractants (sodium citrate/dithionite, ammonium oxalate (dark), acid oxalate (UV radiation), as well as those already mentioned). It was concluded that much of the extractable A1 in soils was associated with organic matter. Addition of lime to one of the soils reduced the amount of A1 extracted by all reagents except dithionite and acid oxalate solutions. There were considerable differences between soils in their release of A1 to continuous leaching with 0.01 M CaCl2. Despite these differences between the soils in organically bound extractable Al, the differences in the amounts and patterns of release of A1 with CaCl2 did not appear to be related to organic matter contents, nor to the other determined properties.  相似文献   

9.
Abstract

The proportion of copper (Cu) that can be extracted by soil test extractants varied with the soil matrix. The plant‐available forms of Cu and the efficiency of various soil test extractants [(0.01 M Ca(NO3)2, 0.1 M NaNO3, 0.01 M CaCl2, 1.0 M NH4NO3, 0.1 M HCl, 0.02 M SrCl2, Mehlich‐1 (M1), Mehlich‐3 (M3), and TEA‐DTPA.)] to predict the availability of Cu for two contrasting pasture soils were treated with two sources of Cu fertilizers (CuSO4 and CuO). The efficiency of various chemical reagents in extracting the Cu from the soil followed this order: TEA‐DTPA>Mehlich‐3>Mehlich‐1>0.02 M SrCl2>0.1 M HCl>1.0 M NH4NO3>0.01 M CaCl2>0.1 M NaNO3>0.01 M Ca(NO3)2. The ratios of exchangeable: organic: oxide bound: residual forms of Cu in M1, M3, and TEA‐DTPA for the Manawatu soil are 1:20:25:4, 1:14:8:2, and 1:56:35:8, respectively, and for the Ngamoka soil are 1:14:6:4, 1:9:5:2, and 1:55:26:17, respectively. The ratios of different forms of Cu suggest that the Cu is residing mainly in the organic form, and it decreases in the order: organic>oxide>residual>exchangeable. There was a highly significant relationship between the concentrations of Cu extracted by the three soil test extractants. The determination of the coefficients obtained from the regression relationship between the amounts of Cu extracted by M1, M3, and TEA‐DTPA reagents suggests that the behavior of extractants was similar. But M3 demonstrated a greater increase of Cu from the exchangeable form and organic complexes due to the dual activity of EDTA and acids for the different fractions and is best suited for predicting the available Cu in pasture soils.  相似文献   

10.
Abstract

Metal availability in soils is often assessed by means of extraction with chemical solutions, among others the chelating agent DTPA (diethylenetriaminepentaacetic acid) and the non‐buffered salt calcium chloride (CaCl2). The same procedures are used for polluted soils that were originally created to assess the nutrient status of arable soils. We studied the influence of various parameters (type of shaker, shaking time, soil to solution ratio, and concentration of chemical extractant) and modify the DTPA and CaCl2 extraction procedures to make them suitable for the study of polluted soils. The chosen extraction ratio and extractant concentration were the followings: 8 g/20 mL of 0.1 MCaCl2 and 2 g/20 mL of 0.005 M DTPA. The optimized procedures were applied to nine soil samples affected by different sources of pollution (mine works, vehicle emissions, and various industries). Cadmium (Cd) showed the highest extractability with both extractants. Depending on the soil, copper (Cu) and zinc (Zn) (using DPTA) and Cu and manganese (Mn) (using CaCl2) were the followings in the extractable amounts. Cadmium, Cu, and Zn were highly correlated in both extractions and with total contents.  相似文献   

11.
Abstract

Soils in southern Australia within the Mediterranean‐type climate zone vary widely in boron concentrations, from potentially deficient to toxic for plant growth. A general method is needed for the determination of boron in soils ranging from acidic to alkaline, with wide ranges of clay content and sodicity.

The amounts of boron extracted were compared following boiling in 0.01M CaCl2 in test tubes in temperature‐controlled programmable digestion blocks, or in Erienmeyer flasks on hot plates under different analytical conditions. Comparisons were also made between CaCl2, hot water, and mannitol extractable boron. All analyses of boron were made by inductively coupled plasma spectrometry (ICPS).

The extraction of boron was dependent on extraction time and temperature of the heating block. Addition of 20 ml of 0.01M CaCl2 to 10g of soil in 250 ml test tubes fitted with air condensers and placed in a pre‐heated temperature‐controlled digestion block set at 140°C and boiled for 30 minutes. This method was found to be a suitable extractant of boron in soils with a wide range of sodicity, pH and extractable boron (from concentrations potentially deficient to toxic for plant growth).  相似文献   

12.
A total of 400 surface soil(0–15 cm) samples were collected from cultivated soils representing four soil series,namely,Hariharapur,Debatoli,Rajpora and Neeleswaram in Orissa,Jharkhand,Himachal Pradesh and Kerala states of India,respectively,and were analyzed to measure the contents of total and extractable Mn and Fe,to establish the relationship among total and extractable Mn and Fe and soil properties,and to characterize the spatial distribution pattern of Mn and Fe in some cultivated acid soils of India. The contents of total as well as extractable Mn and Fe varied widely with extractants and soil series. However,the amounts of Mn or Fe extracted by diethylene triamine penta-acetic acid(DTPA),Mehlich 1,Mehlich 3,0.1 mol L-1 HCl and ammonium bicarbonate DTPA(ABDTPA) were significantly correlated with each other(P 0.01). Based on the DTPA-extractable contents and the critical limits(2 mg Mn kg-1soil and 4.5 mg Fe kg-1 soil) published in the literature,Mn and Fe deficiencies were observed in 7%–23% and 1%–3% of the soil samples,respectively. The content of soil organic carbon(SOC) had greater influence on total and DTPA-extractable Fe than did soil pH. Geostatistical analysis revealed that total and DTPA-extractable Mn and Fe contents in the acid soils were influenced by soil pH,SOC content,and exchangeable cations like potassium,calcium and magnesium. Spatial distribution maps of total and DTPA-extractable Mn and Fe in soil indicated different distribution patterns.  相似文献   

13.
We evaluated the effect of 1 N NH4OAc and sodium-citrate dithionite extractable forms of soil Fe, Al, and Mn on P-sorption of a flooded acid sulfate soil (Sulfic Tropaquepts) and a non-acid sulfate soil (Typic Tropaquepts) under different soil oxidation-reduction and pH conditions. We used Maha-Phot soil (Sulfic Tropaquepts) and Bangkok soil (Typic Tropaquepts) from the Bangkok Plain, Thailand, and incubated them with 0.2% rice straw under aerobic (O2 atmosphere) and anaerobic (N2 atmosphere) conditions at three different levels of pH (4.0, 5.0, and 6.0) for 6 weeks in stirred soil suspensions with a soil to 0.01 M CaCl2 solution ratio of 1:7. After the incubation period, the soil suspensions in the first treatment (control) were not washed or pretreated with any extractants. For the second treatment (II), the soil suspensions were treated with 1 N NH4OAc (buffered to pH 4.0) to remove Fe, Al, and Mn in exchangeable form. In the third treatment (III), the soils suspensions were treated with sodium citrate dithionite solution (20%) to remove Fe, Al, and Mn in the form of free oxides. The soil residues were then equilibrated with KH2PO4 ranging from 0 to 500 mg P kg-1 soil. Sorption isotherms were described by the classical Langmuir equation. The P-sorption parameters under study were standard P requirement (SPR), Langmuir maximum sorption capacity (X m), Langmuir sorption constant (k), and buffering index (BI). Treating soils with 1 N NH4OAc reduced X m by 32–55%, SPR by 68–84%, and also decreased the differences in P-sorption due to the effects of pH and oxidation-reduction conditions. Significant correlations between the P-sorption parameters and the amount of free iron oxides indicated the primary role of iron oxides in P-sorption of acid sulfate soils. Aluminium oxides seemed to play a secondary role in P-sorption of these soils. Manganese also showed an important effect on P-sorption, but the mechanism is ambiguous.This is a contribution from the Wetland Biogeochemistry Institute, Louisiana State University, Baton Rouge, LA 70803-7511  相似文献   

14.
Abstract

Ten easily determined soil parameters related to soil acidity were evaluated for their potential to provide simple, indirect estimates of the exchangeable aluminium percentage (PAL). These parameters were correlated with the PAL in 0.6N BaCl2 extracts of soils collected from lime trials on 4 different parent materials. Six rates of lime (0, 0.75, 1.5, 3, 6, 12 t/ha) were added 3–4 years prior to collection of the samples. The soil parameters examined were the pH of soil suspensions with SMP, Woodruff and New Woodruff buffer solutions; the pH of 1, 5 and 10mM CaCl2 and 0.6N BaCl2 soil extracts, and the aluminium content of 1, 5 and 10mM CaCl2 soil extracts. The best correlations with the exchangeable aluminium percentage for all soils considered, were those based on the aluminium content of the 5mM CaCl2 extract (r=0.976, n=24) followed by the pH of the 0.6N BaCl2 extract (r=0.945, n= 24). Both these methods are suggested as reliable indirect estimates of soil exchangeable alumimium percentage where availability of staff or equipment restrict direct determinations.  相似文献   

15.
Abstract

A laboratory incubation experiment was conducted to study the influence of organic matter and lime application on the recovery of added boron (B) by four different extractants (hot‐CaCl2, mannitol‐CaCl2, tartaric acid, and ammonium acetate) in two B‐deficient acid alluvial soils. Soils were brought to four relatively constant pHs and three organic matter levels before application of B. Recovery percentages of 23.9 to 60.9 of added B by the four extractants indicate a soil fixation of B. This is more so in fine‐than in coarse‐textured soils. Both liming (from pH 4.8 to 6.8) below neutrality and organic matter application increased such recovery of added B in all the extractable forms, the effect being more pronounced in fine‐than in coarse‐textured soils. A positive interaction between liming and organic matter particularly at the latter's higher level was observed. Complexation of added B and coating of the surfaces of Fe‐and Al‐oxides by soluble organic compounds are suggested as the possible reasons for such increased recovery of added B in soils.  相似文献   

16.
Abstract

A pot experiment was carried out in the greenhouse with two loamy sand Dystric Cambisols derived from schist to investigate the effect of liming and phosphorus (P) application on plant growth and P availability and its assessment by four soil test methods: 0.01M calcium chloride (CaCl2), cation anion exchange membrane (CAEM), Egnér‐Riehm, and Olsen procedures. Soils were first incubated for two weeks with lime at four levels, depending on their content of exchangeable aluminum (Al). Phosphorus was added at two rates (75 and 150 mg P kg‐1) and the incubation proceeded for an additional two‐week period. Sudangrass (Sorghum sudanenses cv. Tama) was then planted and harvested four weeks later. During incubation and plant growth, soils were maintained at 70% of field moisture capacity. Although pH value and soil extractable P in original soils were similar, the results showed a significant difference on the effect of liming and P application. Acidity was the major limitation for DM yield in the soil with the highest amount of exchangeable Al, while P availability was the main constraint in the other soil. Liming above pH (0.01M CaCl2) 5.3–5.5 did not increase DM yield in either soil and showed a negative effect on one soil (9.7 to 6.9 and 10.2 to 7.8 g pot‐1). Phosphorus content and uptake by sudangrass increased with liming, revealing a positive effect of lime on the availability of P to plants. Added P showed a lower efficiency in the soil with highest amounts of Al compounds. Soil tests performed after the execution of the pot experiment showed variable tendencies to predict P availability, according to the nature of the procedures and soils. Soluble‐P in 0.01M CaCl2 increased with the rise of soil pH. Extractable CAEM‐P and Egnér‐Riehm‐P also increased with liming, but reflected the soil depletion caused by plant uptake. Extractable Olsen‐P presented the most inconclusive results, suggesting the limitation of this method for acid soils which have been limed.  相似文献   

17.
At low solution concentrations of copper in the presence of 0.05 M CaCl2, adsorption isotherms for copper on soil samples were essentially linear. Although no direct correlations were found between isotherm gradients and individual soil properties, the gradients were of the same order of magnitude as predictions based on gradients obtained for some specific soil components. The soil components which appear to be most important in copper adsorption and which were used to obtain the predictions were organic matter and iron and manganese oxides. The amounts of adsorbed copper remaining isotopically exchangeable or extractable with EDTA in the short term increased with the amount of copper adsorbed but the proportions of adsorbed copper estimated by each of these techniques remained constant. Concentrations of copper in solution increased (adsorption decreased) at pH values below 4.5 and above 6.5.  相似文献   

18.
土壤主要理化性质对湘粤污染农田镉稳定效果的影响   总被引：3，自引：0，他引：3  
崔旭  吴龙华  王文艳 《土壤》2019,51(3):530-535
利用盆栽试验研究了稳定剂(石灰、海泡石联合施用)对湖南、广东两省区不同性质土壤上生长的小青菜(Brassica chinensis L.)生物量、重金属吸收以及土壤pH和重金属提取态含量的影响,探讨了影响镉(Cd)稳定修复效果的土壤性质参数。结果表明:施加稳定剂对增加酸性土壤上小青菜生物量效果显著,土壤pH、有机质(OM)、全量Cd和黏粒是影响小青菜生物量变化的主要因素;土壤pH、阳离子交换量(CEC)、OM、黏粒是影响小青菜Cd含量变化的主要因素;土壤pH、CEC、全量Cd和黏粒是影响土壤提取态Cd含量变化的主要因素。  相似文献   

19.
ABSTRACT

Effect of slag-based gypsum (SBG) and commercial gypsum (CG) on maize was investigated in acidic and neutral soils. A randomized complete block design (RCBD) with seven treatments consisting of three levels (150, 450, and 750 kg ha?1) of SBG and CG with recommended dose of fertilizer (RDF) and one control was maintained. Application of SBG @750 kg ha?1 recorded significantly higher (8.61 and 8.69 t ha?1, respectively) cob yield of maize compared to CG and control treatments in both soil condition. Increased levels of SBG application increased soil pH and EC in both the soils, but decreased with the application of CG. Application of 750 kg SBG ha?1 recorded significantly higher soil available nutrients like phosphorus in acidic soil and potassium in neutral soil. Higher exchangeable calcium and magnesium in acidic soil and exchangeable calcium in neutral soil were recorded with the application of CG @750 kg ha?1. Available sulfur was significantly higher with CG @750 kg ha?1 applied treatment in both soils. CaCl2Si content in acidic soil varied significantly and recorded higher with application of SBG, while CaCl2Si content in neutral soil and AASi in both soils had no significant effect by application of SBG. Significantly higher DTPA extractable micronutrients in acidic and neutral soil were noticed in SBG @750 kg ha?1 applied treatment. However, application of SBG had no significant effect on iron and copper content in neutral soil. Higher uptake of nutrients was recorded with 750 kg SBG ha?1 compared CG applied and other treatments.  相似文献   

20.
Comparison of different methods for the determination of the potassium availability of soils Extractable K was determined in 148 soil samples by using three different lactate solutions (AL, DL, CAL), 0.1 m HCl and 0.0125 m CaCl2 as extracting agents. The extractable portion of the total exchangeable K (K(NH4)) was found to decrease with increasing content of the < 6,3 μm particle size fraction in the samples. Correlation coefficients were calculated for characterizing the relationship between extracted amounts of K (K values) and the ?K numbers”?. The latter serve as a basis for fertilizer recommendations in the Netherlands, where they have been checked in a great number of field trials. The K number depicts the K supplying power of soils as determined by HCl soluble K, content of the < 16 μm size fraction, and pH. The K (CaCl2) values were found to correlate more closely with the K numbers than the amounts of K extracted with lactate solutions. This is because the influence of particle size on K(CaCl2) is eliminated as shown by multiple regression analysis. The strength of bonding of the easily exchangeable K is reflected much better by the K(CaCl2) values than by the lactate values. Improvement of K fertilizer recommendations by taking K(CaCl2) data as a basis can thus be expected. The different methods of recommendation for K fertilization in the Fed. Republic of Germany and in the Netherlands are illustrated for the soils derived from loess.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号