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1.
Abstract

Tropical acidic soils require large inputs of nitrogen (N) and phosphorus (P) fertilizers to sustain crop production. Attempts to use phosphate rock (PR) as a cheaper P source have shown limited success because of low rock solubility. The objective of this study was to evaluate growth and P nutrition of aluminum (Al)‐tolerant maize inbreds fertilized with PR. Twelve Al‐tolerant inbreds from CIMMYT were planted in 2‐kg pots filled with an acidic soil very low in available P and fertilized with 0, 40, or 100 mg kg?1 of Riecito PR or triple superphosphate (SP). Plant shoots were harvested 35 days after planting, and biomass, root length, P uptake, and soil residual P were determined. Inbreds were able to sustain growth when fertilized with PR. There was indication that various mechanisms were involved in the responses to PR fertilization. Cultivars combining high uptake and conversion efficiencies should improve maize utilization of PR.  相似文献   

2.
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   

3.
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   

4.
Abstract

The effectiveness of the application of raw (PR‐1), and partially acidulated phosphate rock (PR), at 25% (PR‐25) and at 50% (PR‐50), was investigated to reduce extractability and plant uptake of Pb, Cd, Cu, Ni, and Zn in three calciorthids soils.Furthermore, the effects of soil treatments on metal extractability were evaluated by sequential extraction. Similarly, such effects were assessed on the phytoavailability of metals of maize (Zea mays L.) through a pot experiment. Water‐soluble and exchangeable metal fractions (the bioavailable fractions) were influenced distinctively by PR treatments and soil properties. In addition, decrease of soluble and exchangeable metal fractions was compensated by an increase in metal extracted from other fractions. Most bioavailable soil metals correlated significantly with their associated level in plant tissue. Finally, plant metal uptake decreased with PR treatments, suggesting that PR application was likely to be effective in controlling metal immobilization in these soils.  相似文献   

5.
Seasonal fluctuation of concentration and flux of major inorganic ions in throughfall, stem flow, snowpack and soil solution was investigated at a natural cool temperature mixed forest in Hokkaido, northern Japan, in order to clarify the effect of snowmelt on the solute dynamics in the forest soil in snow-dominated region. Na+, Ca2+, Mg2+, Cl? and SO4 2? concentrations in soil solution showed a large fluctuation in the snowmelt period. The percentage of output of these elements from soil during the snowmelt period in the annual output was as follows. Mg2+: 51%, Na+ and Cl?: 59 and 60%, SO4 2?: 65%, Ca2+: 77%. Our results indicated that the snowmelt event was very important to quantify the annual elemental budgets in this region. Although the leaching of base cation from the soil was larger than that of inputs and accumulation into the vegetation, annual decreasing rate of acid neutralization capacity (ANC(s)) from the soil was mostly affected by the base cation accumulation into the vegetation, related that the base cations weathering accompanied with bicarbonate was slow due to the acidic and weathered soil in the studied site. It is suggested that the weakly acidic soil which has low ANC(s) in snow-dominated region will be relatively sensitive to the future increase of acidic deposition.  相似文献   

6.
Various crop residues were applied to a strongly acidic tea garden soil to investigate their performance in ameliorating soil acidity. A laboratory study found the performance of crop residues on soil acid amelioration was mainly determined by the combined effect of nitrogen (N) transformation, cation exchange, and ash alkalinity. Nitrogen transformation was varied for different crop residues added, but followed N regulation, resulting in an adverse liming effect. It was assumed that during the release of ash alkalinity, cations replaced soil exchangeable acidity in soil solution, which largely diminished the liming effect of ash alkalinity. That was why soil pH was highly correlated with N transformation process. Furthermore, soil pH was positively correlated with carbon (C)/N ratios of crop residues both in low-level treatment (R 2 = 0.955) and in high-level treatment (R 2 = 0.981). Therefore, crop residues with relative high C/N ratios were considered to be more suitable for long-term pH adjustment of tea garden soils.  相似文献   

7.
土地利用类型对侵蚀黄壤腐殖质及土壤酶的影响   总被引:1,自引:0,他引:1  
[目的]研究土壤侵蚀条件下,土地利用类型对黄壤不同土层深度的腐殖质(胡敏酸、富里酸和胡敏素)和4种重要土壤酶的影响,为保持土壤肥力提供科学依据。[方法]采用锯齿形布点法,采集土壤表层至30cm深度的3个土层土壤样品,用3次4分法淘汰多余样品,再测定相应指标。[结果](1)保持土壤肥力最好的是灌丛和园地,耕地最容易受侵蚀;土壤肥力高低与胡敏素的含量有直接关系。(2)土壤侵蚀导致水分和氮元素流失会影响胡敏酸的含量;林地、园地和耕地土壤表层的富里酸易流失,而草地仅对于土壤表层肥力保持有作用。(3)耕作对土壤表层的脲酶、碱性磷酸酶和过氧化氢酶活性的不利影响较大;土壤侵蚀导致的土壤pH值改变对土壤酶的影响也很明显。(4)相关性分析表明腐殖质各组分含量与4种土壤酶都有着密切的联系且互相影响。[结论]黄壤受侵蚀下,土地利用类型对腐殖质及土壤酶有明显不同的影响。  相似文献   

8.
ABSTRACT

Red acid soil is generally distributed in humid tropical areas under high rainfall. The main constraint is usually the extremely low pH of the soil due to the very intensive leaching of the bases from the soil. At the same time, however, the soluble micro elements, such as iron, are high. This can cause plant toxicity. The liming of acidic soils is normally performed to reduce the iron toxicity as the first step toward providing a balanced nutrition for cultivated plants. The objective of this study is to determine the effects of liming on the soil pH, on the decrease of iron in the soil and on the growth of the pineapple. The research was done in the Greenhouse of the Research and Development Department, PT Great Giant Pineapple, Lampung, Indonesia, from November 2015 to April 2016. The design of the experiment was arranged as a completely randomized design with seven treatments and three replications, consisting of: No dolomite (D0), dolomite 1 t ha?1 (D1), dolomite 2 t ha?1 (D2), dolomite 3 t ha?1 (D3), dolomite 4 t ha?1 (D4), dolomite 5 t ha?1 (D5) with added Fe-EDTA and for the control treatment, no dolomite and no Fe-EDTA (C0). The results showed that an increase in the dolomite dose can increase the pH, potassium (K), calcium (Ca) and magnesium (Mg) in the soil and can decrease the iron (Fe) in the soil significantly. Increasing the pH, K, Ca and Mg and decreasing the Fe in the soil were seen to influence the growth of the pineapple. In particular, the leaf area of the pineapple plant increased considerably. The other parameters also increased, but not significantly.  相似文献   

9.
Cation mobility in acidic soils with low organic‐matter contents depends not only on sorption intensity but also on the solubility of the species present in soil solution. In general, the following leaching gradient is observed: potassium (K+) > magnesium (Mg2+) > calcium (Ca2+) > aluminum (Al3+). To minimize nutrient losses and ameliorate the subsoil, soil solution must be changed, favoring higher mobility of M2+ (metal ions) forms. This would be theoretically possible if plant residues were kept on the soil surface. An experiment was conducted in pots containing a Distroferric Red Latosol, with soil solution extractors installed at two depths. Pearl millet, black oat, and oilseed radish residues were laid on the soil surface, and nitrogen (as ammonium nitrate) was applied at rates ranging from 0 to 150 mg kg?1. Corn was grown for 52 days. Except for K+ and ammonium (NH4 +), nitrogen rates and plant residues had little effect upon the concentrations and forms of the elements in the soil solution. Presence of cover crop residues on soil surface decreased the effect of nitrogen fertilizer on Ca leaching. More than 90% of the Ca2+, Mg2+, and K+ were found as free ions. The Al3+ was almost totally complexed as Al(OH3)0. Nitrogen application increased the concentrations of almost all the ions in soil solution, including Al3+, although there was no modification in the leaching gradient.  相似文献   

10.
Abstract

An improved management of phosphorus (P) is crucial for increasing crop production and improving environmental quality of acid infertile soils. Laboratory analyses and greenhouse experiments were conducted to evaluate effects of phosphate rock (PR), coal combustion by‐product (BP), limestone, and cellulose application on the relationship between soil test P and crop growth in acidic soil. Application of PR, BP, limestone, and cellulose increased soil pH, exchangeable calcium (Ca) and magnesium (Mg), and extractable P, and decreased free aluminum (Al) ion in the acid soil. Addition of BP or limestone increased P availability efficiency [PAE, mg dry matter yield (DMY) of plant per mg soil extractable P by Olsen‐P procedure] and P utilization efficiency (PUE, mg DMY of plant per mg P in the plant). There was significant positive correlation between the PAE and BP rates applied alone (r2=O.979, p<0.01) or with either PR (r2=0.972, p<0.01) or PR plus cellulose (r2=0.985, p<0.01). The PUE of ryegrass was significantly correlated with BP rates alone (r2=O.957, p<0.01) or with either PR (r2=0.906, p<0.01) or PR plus limestone (r2=O.699). The increase in PAE and PUE of ryegrass caused by BP and limestone reflected more plant root growth from increased availability of Ca and Mg and higher soil pH.  相似文献   

11.
Abstract

With a peat soil similar amounts of phosphorus (P) were coprecipitated with humic acid from alkali extracts over a limited range of strongly acidic pH, whereas with a mineral soil the amount was pH dependent. The difference between the two soils relates to the much greater total amounts of inorganic P and aluminum (Al) present in the extract of the mineral soil. In this acid mineral soil, Al rather than iron (Fe) may be involved in the formation of metal bridges in humic acid‐metal‐inorganic P complexes. Neither Al or Fe were implicated in binding of organic P to humic acid. The P species observed in humic acids was dependent on the pH at which they were precipitated from the alkali extracts. In the peat soil the inorganic P was an order of magnitude lower than the organic P.  相似文献   

12.
Phosphate rock (PR), limestone, coal combustion by-product (CCBP) high in Ca and high organic manures are potential amendments for increasing agricultural production in the acidic soils of the Appalachian region. The objective of this study was to examine effects of PR, CCBP and cellulose addition on soil microbial biomass in an acidic soil based on the measurement of soil microbial biomass P (P mic) and on the mineralization of organic matter. Application of PR alone or in combination with CCBP increased P mic. The P mic was far less when the soil received PR in combination with limestone than with PR application alone or PR in combination with CCBP. Either CCBP or limestone application alone considerably decreased P mic in the soil due to reduced P solubility. Cellulose addition alone did not increase P mic, but P mic was significantly increased when the soil was amended with cellulose in combination with PR. The decomposition of added cellulose was very slow in the soil without PR amendment. However, mineralization of both native organic matter and added cellulose was enhanced by PR application. Mineralization of organic matter was less when the soil was amended with PR in combination with high rates of CCBP (> 2.5%) because PR dissolution varied inversely with amount of CCBP addition. Overall, CCBP had no detrimental effect on soil microbial biomass at low application rates, although, like limestone, CCBP at a high rate may decrease P mic in P-deficient soils through its influence on increased soil pH and decreased P bioavailability in the soil. Application of PR to an acidic soil considerably enhanced the microbial activity, thereby promoting the cycling of carbon and other nutrients. Received: 11 December 1995  相似文献   

13.
Abstract

Soils were amended with metal and arsenic (As) immobilizing soil additives [steel shots (SS 1% w/w), beringite (B 5% w/w), combination steel shots+beringite (SSB 1% SS + 5% B), hydroxyapatite (HA 0.5,1, and 5% w/w)]. The effectiveness of the additives in reducing metal and As mobility was assessed by means of chemical extractions with 1M calcium nitrate [Ca(NO3)2] in the case of metals and distilled water in the case of As. Among the additives tested, B, SSB, and 5% HA were most effective in reducing the mobility of cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn). Moreover, the effect of these additives was consistent in the different soils and their use might, therefore, be more or less universal. The lowest amount of As was extracted in soils amended with B, SS, and SSB. The effect of B was, however, soil dependent. The addition of HA led to higher As mobility due to the phosphate‐arsenate competition for the sorption complex of the solid soil phase. Therefore, the use of HA at combined metal‐As polluted sites has to be taken with care. Based on this study, it can be concluded that the addition of SSB seems the most promising treatment for the remediation of mixed metal‐As polluted sites.  相似文献   

14.
Abstract

Aquasorb PR3005A, a hydrophilic polymer (a salt copolymer polyacrylamide), and garden waste compost were added to a loamy sand and a loam soil in pots to assess their impact upon soil physical properties at two different evaporation potentials. Compost was mulched and incorporated, the Aquasorb was incorporated, and their effect on temperature and amelioration of soil water content and evaporation was investigated. Mulching with compost reduced evaporation and increased soil temperature. Maize (Zea mays var. single cross 704) was sown in the same pots later, and growth indicator factors (plant height, fresh and dry weight, root weight, and leaf area) were compared. It was concluded that compost mulch application is beneficial to soil water retention whereas compost incorporation did not show these benefits. Compost mulch advances seedling emergence and enhances early growth through hydrologic soil amelioration. High rates of Aquasorb were also beneficial in advancing the emergence and early growth of maize seeded in loamy sand. The hydration capacity of Aquasorb is reduced as the electrolyte concentration and electrical conductivity are increased. Increased electrolyte concentration in soil solution, through drying, may result in gel dehydration and water release at potentials greater than field capacity, which may be lost to drainage. Furthermore, it is concluded that pot experiments with amendments fail to simulate field conditions.  相似文献   

15.
[目的] 为探究不同耕作模式和生物炭施加量对黑土区农田土壤氮磷转化和玉米生长发育的影响。[方法] 通过野外大田试验,设置2种耕作(深耕和浅耕)和5个生物炭添加处理(0,3,6,9,12 t/hm2),探究不同耕作模式和生物炭施加量对土壤氮磷组分、酶活性及玉米生理特性的综合影响。[结果] (1)深耕和浅耕配合施加生物炭可有效改善土壤结构,提高团聚体几何平均直径,降低破坏百分比,且深耕处理效果优于浅耕处理;(2)施加生物炭提高土壤氮磷组分、脲酶活性和碱性磷酸酶活性,施加9 t/hm2生物炭效果最好,且深耕更为显著;(3)深耕处理下生物炭施加量达到9 t/hm2时,提高叶片的全氮、全磷含量和谷氨酰胺合成酶活性,降低酸性磷酸酶活性;(4)深耕条件下施加9 t/hm2生物炭的玉米的产量达到17.37 t/hm2,相比于0提高28.9%。[结论] 深耕处理并施加9 t/hm2生物炭对于黑土区农田养分环境和作物生长提供参考意义。  相似文献   

16.
Purpose

Soils have the ability to retain potentially toxic elements (PTEs) through different chemical processes that promote low mobility of these elements, such as the precipitation of secondary phases of Fe, which facilitate the adsorption/co-precipitation of PTEs. The main objective of this study was to evaluate the mobility of PTEs present in an acid solution in two soils with different concentrations of calcite, understanding the role of secondary iron phases in the retention of these elements.

Materials and methods

To evaluate this phenomenon, intact soil columns of two different types of soils from the Sonora River in Northwest Mexico were exposed to an acid solution with high concentration of dissolved PTEs (mainly Fe, Al, and Cu).

Results and discussion

The Tinajas soil was free of carbonates while the Bacanuchi soil had more carbonate content than the Tinajas soil. Secondary precipitates corresponding to secondary phases of iron (mainly ferrihydrite and jarosite) were identified by X-ray diffraction. Using scanning electron microscopy, the PTEs retained in the soils were identified. The presence of calcite favored the neutral pH values in the collected leachates in the Bacanuchi soil; consequently, the mobility of the PTEs present in the acid solution was nullified. Furthermore, this process facilitated the retention of the toxic elements in the Bacanuchi soil.

Conclusions

The retention of PTEs was 100% in the Bacanuchi soil where the natural acid-neutralizing capacity in this soil was associated with calcite. The formation of secondary phases of Fe, among them ferrihydrite, jarosite, and schwertmannite, mainly in Bacanuchi soil, promoted the retention of Al, As, Cd, Cu, Fe, Mn, and Pb (elements analyzed in this work). Results of this work can provide key insights to improve cleanup and conservation strategies in mining sites.

  相似文献   

17.
When evaluating phosphate rock (PR) dissolution, previous to the extraction with sodium hydroxide (NaOH), dry soil samples with PR were extracted with three solutions to remove exchangeable and solution calcium (Ca) [sodium chloride (NaCl) 1 M, buffered NaCl with ethylenediaminetetraacetic acid (EDTA) (NaCl–EDTA), and NaCl buffered at pH 7 with triethanolamine (TEA) (NaCl–TEA)] for comparison with the extraction of soil samples without any prewash. In acidic soils, up to 51% of applied P was recovered during the NaCl extraction because of the high exchangeable acidity released during the extraction. In soils with exchangeable Ca>2 cmol(+)kg?1, high EDTA quantities also promoted PR dissolution. The NaCl–TEA solution efficiently removed Ca, avoiding PR dissolution and P retention by calcium hydroxide [Ca(OH)2] during the NaOH extraction. Thus, when evaluating PR dissolution we recommend the use of NaCl–TEA to remove Ca. We also recommend the same procedure when applying the Chang and Jackson fractionation to calcareous soils and soils submitted to PR application.  相似文献   

18.
Abstract

Many vegetable growers in Japan practice a unique waterlogged cultivation method with ample nitrogen (N) supply and microbial supplements, reporting vigorous plant growth, no soilborne diseases, and high yields. We simulated waterlogged soil conditions in greenhouse experiments to examine effects of soil pH and redox potential (Eh) as well as microbial influence on the growth of tomato seedlings. Soil pasteurization enhanced seedling growth whether the acidic, volcanic soil was waterlogged or well-drained. Among various antimicrobials, only soil treatment with polymyxin B improved shoot growth in nonpasteurized soil. The seedlings grew best in pasteurized acidic, waterlogged soil fertilized with ample potassium nitrate (KNO3), which maintained soil Eh above zero. In nonpasteurized soil, growth was severely stunted by raising soil pH progressively to 8.5 while Eh dropped to –194?mV. The results suggested that heat-sensitive Gram-negative soil bacteria and low soil Eh were key factors limiting the growth potential of tomato plants in waterlogged soils.  相似文献   

19.
Addition of organic amendments can alleviate the level of aluminum (Al) phytotoxicity in acid soils by affecting the nature and quantity of Al species. This study evaluated the transformation of Al in an acidic sandy Alaquod soil amended with composts (10 and 50 g kg?1 soil of yard waste, yard + municipal waste, GreenEdge®, and synthetic humic acid) based on soil Al fractionation by single and sequential extractions. Though the organic compost amendments increased total Al in soil, they alleviated Al potential toxicity in acidic soil by increasing soil pH and converting exchangeable Al to organically bound and other noncrystalline fractions, stressing the benefits of amending composts to improve acid soil fertility. The single‐extraction method appears to be more reliable for exchangeable Al than sequential extraction because of the use of nonbuffered pH extract solution.  相似文献   

20.
This study focuses on fluxes of elements from, and changes in the soil properties of shallow organic material rich soil as a result of changes in precipitation acidity. Intact soil columns including natural vegetation from two areas (one exposed to acidic precipitation and one unpolluted) were used in a lysimeter experiment. The lysimeters were watered with simulated normal rain (pH 5.3) or simulated acidic rain (pH 4.3) for four years. Sulphuric acid and ammonium nitrate were used to regulate the quality of the simulated rain. Significantly more SO4 2? was leached from lysimeters receiving acid rain. Rain acidity had no significant effect on NO3 ? leaching. Significantly more Mg2+ was leached from lysimeters receiving acid rain, but this only applied for the soils from the unpolluted area. Four years of treatment did not cause any significant effect on the soil acidity and the amounts of base cations in the soil. The more acidic rain did, however, cause a significant lower cation exchange capacity. For the soils from the polluted area the acid precipitation did cause a lowering of the exchangeable K+ in the upper 5 cm of the soil. Different quality of the soil organic material indicated by different vegetation types appeared to cause significant differences in the amount of components leached from the soil, but did not cause any difference in response to the different rain qualities.  相似文献   

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