Soil nutrient leaching in response to simulated acid rain treatment

Soil and soil solution nutrient concentrations were evaluated over a 30-mo period to determine the impact of simulated acidic precipitation (70:30 equivalent basis H₂SO₄: HNO₃) at pH values of 5.7, 4.5, 4.0, and 3.5 on forest. microcosms. Soil nutrient analysis indicated significantly lower concentrations of exchangeable Ca and Mg in the top 3.5 cm of the mineral soil after 30 mo of pH 3.5 treatment. Leachate collected from the pH 4.5, 4.0, and 3.5 treatments at the 25 cm depth (below the Å.: horizon) exhibited significant increases in Cl, NH₄, PO₄, K, and SO₄ concentrations compared to the pH 5.7 treatment. At the 50 cm depth (mid-profile) all leachate element concentrations except NH₄ increased significantly in response to treatment. At the 100 cm depth (profile bottom), no significant effects of treatment on leachate chemistry were observed. The elevated base cation concentration values found in the 50 cm soil solution samples support at least partially the described reduction in Ca and Mg in the surface soil horizon. The 100 cm concentration data indicate that cations mobilized out of the Å.: and upper B horizon in response to treatment were immobilized before reaching the bottom of the soil profile. Evaluation of nutrient flux out of the microcosm at the 100 cm depth did not indicate any statistically significant response to the treatment. Nitrate rather than SO₄ was found to be the dominant anion leaving the microcosm by an average factor of ～7 to 1.     

O_3浓度升高对麦季土壤-植株系统中微量元素的影响

利用O3-FACE平台研究近地面臭氧浓度升高（目标值比周围大气高50%）对2009—2010年间麦季各生育期不同深度（0～5cm,5～10cm和10～15cm）耕层土壤微量元素有效性和成熟期地上部分微量元素累积量的影响。结果表明,近地层大气O3浓度增加提高了麦季耕层（0～15cm）土壤中有效性Fe、Mn含量,降低了有效性Cu、Zn含量,对Zn的减幅达27.3%（P〈0.05）;大气O3浓度升高对土壤5～10cm土层DTPA提取态Fe、Mn、Cu、Zn的影响最大;高O3浓度显著降低了5～10cm和10～15cm土壤DTPA-Zn含量（P〈0.05）。O3浓度升高降低了小麦成熟期生物量和微量元素累积量。对不同层次土壤有效态微量元素和成熟期微量元素累积量对O3浓度升高响应进行了分析,同时指出应从土壤性质和作物生长两个方面进一步研究全球大气环境变化对土壤有效态微量元素的影响机制。     

Acidification of Solid and Solution Phases at Greater Depths (> 150 cm) at Solling Spruce Site

The acidification of the soil and percolation water at soildepths from 150 to 500 cm was studied at the Solling spruce sitefrom 1991 to 1996. NH₄Cl exchangeable cations of the fineearth and bedrock fractions were obtained from different depthsand the soil solution composition was monitored at 150, 200,300, 400 and 500 cm depths using seven suction lysimeters at each depth.In the seepage water collected from 150 and 200 cm depth, pHvalues decreased in the period 1991 to 1996, but no significantchanges were observed in solutions collected below 200 cm depth.Element budgets of Al and M_b (Na, K, Mg, Ca) cationsindicated that buffering by exchange of Al with M_b cationsoccurred mainly in surface 200 cm soil depth. High variabilities in concentrations of SO₄ (at 150 cm) andM_a (Al, Mn, H, Fe) cations (at 300 and 500 cm) wereobserved. High variabilities in M_a cations could beassigned to one of the lysimeters at each depththat extracted low pH solutions. The amount of exchangeablecations in the fine earth and the bedrock fractions indicatedthat the acidification front (exchangeable M_b cations < 80equivalent percent) had occurred to soil depth of more than 360cm, but the extent of acidification that might have occurred inthe preindustrial period is not known. In both fine earth andbedrock fractions, depthwise changes of exchangeable M_a andM_b cations were quite similar, suggesting that rockfractions have contributed to proton buffering not only bysilicate weathering but also by cation exchange.     

大气O_3浓度升高对稻季耕层土壤溶液CaMg浓度的影响

利用中国稻/麦轮作系统O3-FACE（Ozone-Free Air Concentration Enrichment）试验平台,研究了大气O3浓度升高（比周围大气高50%）对稻季不同生育期耕层土壤溶液中Ca、Mg浓度的影响。结果表明,大气O3浓度升高对稻田0~15 cm耕层土壤溶液Ca浓度无明显影响,但Mg浓度呈现降低趋势;降低了15 cm处土壤溶液Ca、Mg浓度,其中对Mg浓度的降低幅度为20.97%,且达显著水平;大气O3浓度升高可改变耕层土壤溶液中Ca、Mg离子在不同深度的分布,降低15 cm处土壤溶液Ca、Mg浓度与5 cm处比值,降低幅度分别为13.50%、34.29%。文章指出大气O3浓度升高会对稻田生态系统土壤Ca、Mg元素地球化学循环产生重要影响,并可能因此影响稻米产量和品质。     

秦皇岛市蔬菜大棚全盐及盐分组成离子变化的研究

通过对不同棚龄、不同土层、不同季节的蔬菜大棚土壤全盐及盐分组成离子变化的研究表明,大棚土壤全盐含量明显高于相邻棚外土壤,大棚土壤全盐含量随着棚龄的增加而增加,大部分大棚土壤已达到中度盐渍化的程度,同棚龄不同土层全盐含量由上而下呈下降的趋势,大棚土壤全盐含量季节变化2月份明显高于9月份。不同棚龄的大棚土壤盐分组成离子Na+、K+、Ca2+、Mg2+、Cl-、SO42-、HCO3-、NO3-含量,在0～20cm土层中均明显高于相邻棚外土壤,其含量随着棚龄的增加而增加,其中,K+、Ca2+、NO3-、SO42-最为明显,是造成大棚土壤表层盐渍化的主要离子。造成大棚土壤盐渍化的主要原因是大量使用化学肥料,另外,耕作、灌溉等管理方式不当也是造成棚内土壤盐渍化的原因。     

Heavy Metal Concentrations in Soil Solution, Soil and Needles in a Norway Spruce Stand on an Acid Sulphate Forest Soil

The effects of soil processes, related to the oxidation of sulphide sediments, on heavy metal concentrations in the soil and soil solution were investigated in a Norway spruce stand on a fine-textured, acidic soil rich in sulphates located on the isostatic land-uplift western coast of Finland. The age of the soil is ca. 300–400 years, and the soil texture is silt and till. The chemical properties of the soil and soil solution clearly reflected the formation of acid sulphate (AS) soil. Compared to background reference values for podzolic coniferous forest soil, the pH of the soil solution in the mineral soil (20–40 cm depth) was very low, and the Al, Fe and S concentrations extremely high. The Zn and Ni concentrations in the soil solution were also strongly elevated, and similar to the concentrations reported close to anthropogenic heavy-metal emission sources. The concentrations of Cd and Cu were also frequently elevated. In contrast, the acidity and metal concentrations of the soil solution sampled in the organic layer were not elevated. Similarly, exchangeable Zn and Ni concentrations were also elevated in the mineral soil, but not in the organic layer. Because Norway spruce has a very superficial rooting system and the zone with exceptionally high metal concentrations did not extend up to the topmost soil layers, sulphide-oxidation derived soil acidification is not likely to pose a serious threat to forest ecosystems growing on this type of site. Despite the elevated concentrations of protons and many metals in the mineral soil and soil solution (20–40 cm), the nutrient status of the spruce stand was satisfactory and the general health of the stand has been reported to be relatively good.     

苏打碱化土壤盐分离子与相关性分析

选取典型苏打碱化土壤剖面,分析了0～200cm深度主要盐分离子(Ca2+、Mg2+、Na+、K+、CO32-、HCO3-、Cl-和SO42-)的垂直分布规律。对各离子之间的相关性进行了统计分析。结果表明,测试土样离子以Na+和HCO3-离子为主,其剖面分布规律是表层含量较低,在80cm左右逐渐增至最大值,其后离子含量随深度而降低,至160cm以下则又随深度而增加,即在整个土壤剖面上大致呈倒"S"曲线分布。CO32-、HCO3-、Cl-与Na+,CO32-、HCO3-与Cl-之间均是相关系数大于0.80的极显著相关;除K+离子外,其它7个离子间均具有显著相关性,这表明该苏打碱化土壤盐分离子组成具有复杂性的特点。     

黄土高原地区土壤水分区域动态特征

黄土高原地区土壤水分动态特征:一是土壤墒情恢复时间,由南向北和由东向西逐渐提高,高原北部和西部,接近与农作物生长同步,对提高降雨利用率有利;土壤失墒主要分布在两个时期:第一个时期在9—12月份,日平均失水0.64mm,失水量在平均值以上,为丰水失水期,第二个时期在3—7月份,日平均减少0.5—2.34mm,失水量在年平均值以下,为亏缺失水期。冬季蒸发量较少,地区之间有所不同,南部塬区为微弱蒸发,北部丘陵区为缓慢蒸发,西部地区为基本稳定期。二是剖面水分分布分为速变层、活跃层、次活跃层和相对稳定层四个部分。黄     

On-Site Assessment of Extractable Soil Nutrients after Long-Term Biosolid Applications to Perennial Forage

The objective of this study was to evaluate soil nutrient loading and depth distributions of extractable nitrogen (N), phosphorus (P), and potassium (K) after long-term, continuous annual surface applications of anaerobically digested class B biosolids at a municipal recycling facility in central Texas. Commercial forage production fields of coastal bermudagrass (Cynodon dactylon L.) were surface applied at 0, 20, 40, or 60 Mg dry biosolids ha^?1 y^?1 for 8 years. Application duration was evaluated in fields treated with 20 Mg dry biosolids ha^?1 y^?1 for 0, 8, or 20 years. Total soil loads of extractable inorganic N and P increased linearly with application rate, but only extractable P increased with duration. Neither total load nor soil distribution of extractable K was affected by biosolid applications. Mineralization of biosolid-derived organic N and P likely contributed to elevated concentrations of nitrate throughout the soil profile (0–110 cm) and orthophosphate in surface soils (0–40 cm).     

脱硫石膏施用下宁夏盐化碱土水盐运移特征

为定量描述脱硫石膏施用下盐化碱土土壤剖面盐分与淋洗水量的关系,通过室内土柱淋洗试验开展了脱硫石膏施用下不同淋洗水量对宁夏盐化碱土水盐运移影响的研究。结果表明:施用脱硫石膏对增加水分入渗和降低0—20cm土层土壤pH、盐分含量产生了积极影响,土壤脱盐率84.39%~95.41%,但较大水量的淋洗有可能会加剧土壤碱化。连续淋洗条件下,最大脱盐深度位于60—80cm土层。脱硫石膏施用下,0—20cm土层Cl~-、Na~+溶脱率随淋洗水量的增加变化不大,低淋洗水量下,SO_4~(2-)溶脱率低于Na~+和Cl~-,高淋洗水量下,3种离子溶脱率接近;20—40cm土层主要盐分离子溶脱率由大到小依次为Cl~-、SO_4~(2-)、Na~+,各离子脱盐率随淋洗水量的增加先增加较快后趋于平缓。当淋洗水量达到60cm时,SO_4~(2-)和Na~+在80—100cm土层累积,Cl~-则运移至100cm土层以下。     

Stratification of nutrients in soil for different tillage regimes and cotton rotations

Crop management practices, especially tillage and rotation, can impact soil nutrient stratification, crop growth, and yield. The objectives of this study were to determine the soil-profile distribution of plant-available nutrients in four depth intervals from 0 to 90 cm for different cotton (Gossypium hirsutum L.) cropping systems, tillage regimes, and N fertilization rates in a south-central Texas silty clay loam soil after 5 years of treatment imposition. Distribution of nutrients in the soil profile varied between cropping systems (continuous cotton monoculture and cotton–corn (Zea mays L.) rotation), conventional (CT) and reduced tillage (RT), and N fertilization rates (0, 80, and 160 kg N ha⁻¹). Plant-available P showed the greatest stratification and was 426% higher at 0–15 cm than at 60–90 cm, while SO₄ had the greatest increase (42%) with depth. The percentage decrease from 0–15 to 60–90 cm was 47% and 147% for NO₃ and K, and 76%, 12%, 43%, and 232% for Mn, Fe, Cu, and Zn, respectively. In contrast, Ca and Mg concentrations increased 22% and 15%, respectively, from 0–15 to 60–90 cm. Increasing the N fertilization rate increased plant-available NO₃ and SO₄ but decreased K, Fe, Cu, and Zn concentrations. Inclusion of corn in rotation with cotton decreased plant-available Mn, Fe, and Cu from 15 to 90 cm relative to continuous cotton at 160 kg N ha⁻¹. For unfertilized soil, rotation increased micronutrient concentrations at 15–60 cm compared to continuous cotton. On average, CT cotton–corn had significantly lower K, Ca, Mg, Na, and SO₄ concentrations than CT continuous cotton. Reduced tillage and diversified cropping systems altered the distribution of plant-available nutrients in soil relative to CT and continuous cotton. In fact, RT increased plant-available P and NO₃ in surface soil, which may have contributed to higher lint yields than CT continuous cotton.     

Impacts of Vermicompost and Nitrogen,Phosphorus, and Potassium Application on Soil Fertility Status in Arecanut Grown on a Laterite Soil

A field experiment (1998 to 2010) investigated the effects of vermicompost (VC) and chemical fertilizer (CF) application alone or in combination on soil fertility status in arecanut. Vermicompost significantly increased the soil pH (6.3) over CF and integrated treatments (5.7–5.8). Greater soil organic carbon was noticed with VC (2.85–3.00%) than with CF (1.72–1.89%) and VC + CF (1.89–2.55%) in 2009. Soil test phosphorus (P) (mg kg^–1) significantly increased with VC 200% nitrogen (N) equivalency (35.3) compared to other treatments (8.5–23.3) at the 0- to 30-cm depth in 2009. In 2003, soil test potassium (K) (mg kg^–1) was significantly greater with CF at depths of both 0–30 cm (162–187) and 30–60 cm (172–214) than VC and control. Soil test K depleted with VC application in 2009. Application of VC significantly improved soil test calcium (Ca) and magnesium (Mg) compared to CF, CF + VC, and control at 0–30 cm deep. Soil test values for micronutrients increased in 2009 compared to initial status.     

土壤厚度对天然草地植被盖度和生物量的影响

土壤厚度是土壤肥力存在和植物生长的重要物质基础.本文调查了内蒙古东部地区多伦、锡林浩特和巴林左旗3个长期保护天然草地的土壤厚度和植被盖度等植物生长状况.结果表明,天然草地植被盖度、地上生物量和高度随土壤厚度的增加而增大.当土壤厚度小于20 cm时,植被盖度和地上生物量随土壤厚度的降低急剧减小,当土壤厚度小于10 cm时,植被类型为非地带性植被,盖度小于30%,地上生物量小于150 g/m2;当土壤厚度大于20 cm后,植被盖度一般大于80%,地上生物量接近或大于200 g/m2,而且土壤厚度大于20 cm后植被盖度和地上生物量随土壤厚度的继续增大变化平缓.研究区地带性天然草地植被正常生长的最低土壤厚度为20 cm左右.     

马尾松纯林改造成针阔混交林后土壤化学性质的变化

在25 a生的马尾松林下分别套种火力楠、闽粤栲、苦槠、格氏栲、青栲和拉氏栲等阔叶树种的1 a生幼苗,16年后形成郁闭的针阔混交异龄林。土壤化学分析结果显示,在马尾松林下套种阔叶树(除青栲外)明显增加了林下表层土壤(0~20 cm)的有机质含量。各林分下土壤全K、全M g、全C a、全N和全P的平均含量分别为11.41,6.64,4.33,1.45,0.46 g/kg,表明土壤K、M g、C a的含量比较丰富,而N和P则相对缺乏,营造混交林在一定程度上增加了土壤N、P含量。所有混交林深层土壤(20~60 cm)的有效N、P含量均大于马尾松纯林,而有效K的含量则相反。混交林下0~20 cm,20~40 cm和40~60 cm土壤的平均pH值分别为4.40,4.61和4.68,而马尾松纯林下各土层的pH值则依次为4.39,4.41及4.42,说明在马尾松林下套种阔叶树在一定程度上降低了20 cm以下土层的活性酸度。套种阔叶树(除苦槠外)后由于降低了土壤交换性酸度,增加了土壤盐基离子浓度,从而明显提高了土壤盐基饱和度。     

越冬期埋土防寒层厚度对贺兰山东麓葡萄园土壤温度的影响

2019/2020年和2020/2021年冬季于贺兰山东麓葡萄园开展不同埋土防寒层厚度试验,结合不同深度土壤温度监测结果,研究越冬期葡萄园埋土防寒层覆盖下根区土壤温度变化规律,明确不同埋土防寒层厚度对根区土壤温度和葡萄越冬冻害的影响,为葡萄越冬冻害监测、评估及葡萄园冬季埋土管理提供参考。结果表明：（1）酿酒葡萄越冬期（12月−翌年2月）土壤温度呈先下降后上升的趋势;土壤温度随土层深度的增加而增加,波动随深度增加而缩小,埋土防寒层的覆盖,进一步减少了土壤温度的波动。（2）土壤温度随着埋土防寒层厚度的增加而增加,与不埋土处理（H0）相比,埋土防寒层厚度60cm（H60）处理, 20cm日最低土壤温度冬季可提高0.2～2.7℃,冬季平均可提高1.1℃;40cm土壤温度冬季可提高0.1～1.3℃,冬季平均可提高0.6℃。（3）0cm、20cm、40cm土壤温度日较差随着埋土防寒层厚度增加而减小,且极值出现时间依次滞后,60cm土壤温度几乎恒定。（4）20cm土壤温度,根干（C0）处显著高于距根干50cm（C50）、距根干100cm（ C100）和距根干150cm（C150）(P<0.05),距离根干越远土壤温度越低。土壤温度最低日,埋土防寒层厚度30cm、40cm、50cm三个处理根干（C0）处20cm土层温度较C50、C100和C150分别提高1.7～2.2℃、1.7～3.3℃、2.4～3.4℃。可见,根系受冻风险随土壤深度增加而降低,增加埋土防寒层厚度可提高土壤温度,减少土壤温度的波动,最低温度出现的时间随着埋土防寒层厚度增加而出现滞后。越冬冻害发生程度随埋土厚度增加而减少,其中副根受冻率高于主根。     

开垦年限对干旱区土壤理化性质及剖面无机碳的影响

为阐明开垦年限对土壤理化性质及无机碳的影响,进一步了解干旱区土地开垦进程中的土壤质量变化规律和碳吸收与存储过程,以开垦年限分明的典型区—新疆三工河流域阜北农场为研究区,调查、分析了不同开垦年限(已开垦0,1,3,5,15,30,50a)剖面土壤的pH值、盐分、无机碳含量与储量的分布特征、变化规律及开垦年限对它们的影响。结果表明:(1)已开垦土地的土壤pH值随土层深度的增加而升高;随开垦年限的延长,0—60cm(耕作层)的土壤pH值显著降低(P0.05),60—140,140—200cm土壤pH值则升高。不同开垦年限的土壤盐分在剖面上呈"S"型分布,研究区土壤盐分为表聚型;随着开垦年限的延长,土壤盐分聚集层逐渐下移,各剖面平均含盐量减少。开垦历史的延长,有助于排盐排碱。(2)不同开垦年限的土壤无机碳含量与储量:0—60cm显著低于60—140cm,60—140cm显著低于140—200cm(P0.05)。随着土层深度的增加,土壤无机碳储量占全碳的比例增大。随着开垦年限的延长,0—60cm耕作层土壤无机碳含量、储量呈"减少—增加—减少"的变化趋势,无机碳储量占全碳的比例减少。与原始荒地相比,开垦50a时,0—60cm耕作层的土壤无机碳储量减少了55%;0—200cm土壤无机碳储量增加了11.74kg/m~2,无机碳储量所占全碳的比例降低了1.28%。(3)开垦年限的延长对土壤pH、盐分及无机碳的显著影响深度不同,分别集中于0—60cm耕作层,0—140cm及整个研究深度范围内。     

Düngung mit gebranntem Magnesit und Magnesiumhydroxid zur Standortmelioration in einem stark geschädigten Fichtenökosystem

Fertilization with calcined magnesite and Mg-hydroxide for site amelioration in a heavily damaged Norway spruce ecosystem Fertilization experiments with calcined magnesite and Mg-hydroxide were carried out in a heavily damaged, 60-year old Norway spruce ecosystem at Hohe Matzen in the Fichtelgebirge/NE-Bavaria. The site is characterized by high atmospheric inputs with deposition rates of 1.25 kg H, 42 kg S, and 32 kg N per ha and year, and low pH-values of the soil (typic Dystrochrept derived from granite). The trees show severe symptoms of needle yellowing due to Mg-deficiency. Fertilization resulted in manyfold increased Mg-concentrations in soil solution down to 70 cm soil depth and a significant increase of pH down to 25 cm mineral soil depth. Nitrate concentrations were higher after fertilization, but decreased within 15–24 months below the control level. The higher solubility of the Mg-hydroxide resulted in an earlier and clearer pH-increase paralleled by a decrease of the NO₃-concentrations. As a mean over the whole experimentation period no increased N-output from the soil was found after hydroxide application. Fertilization also increased the amount of exchangeable Mg down to 40 cm mineral soil depth. Application of Mg-hydroxide leads to higher Mg-contents in recent-year needles three vegetation periods after fertilization. The lower solubility of magnesite results in a half- to one-year delay in its effects on soil chemical parameters with no reaction of the needle contents within this period.     

冀西北高原土壤冻融特征研究

为明确冀西北高原寒季土壤冻融时空范围及冻融前后储水量变化,通过设计控制性田区,采用时域反射仪(TDR)进行了定位连续观测。结果表明:冀西北高原区冻土深度为200 cm;0~200 cm土体结冻期持续约106 d,融冻期持续35 d,土体融冻速率大于冻结速率。随土层加深,土壤稳定冻结期缩短。封冻期间土体少量耗水,土壤失水主要发生在0~40cm土层。冻结过程有利于保持土壤水分,利于春季植被返青。研究结果为冀西北高原土壤水资源保持、环境保护及植被高效生产提供理论依据。     

浙江省茶园土壤锰含量状况研究

2002年对浙江省部分茶园锰调查结果表明,浙江省茶园全4锰含量0～20cm土层,平均为357.33±265.26mgkg-1,20～40cm土层,平均为361.69±268.69mgkg-1。有效锰含量0～20cm土层,平均为51.16±30.16mgkg-1,20～40cm土层,平均为38.32±25.85mgkg-1,约占全锰含量的15%左右,茶园缺锰率约占30%左右。从上下土层来看,表现出上层锰含量要比下层高。茶树吸收锰与土壤有效锰含量呈极显著正相关,随着叶片的成熟度增加,锰积累增加,同时茎干部也是锰累积的部位。土壤有效锰含量与土壤pH、Al、成土母质有关。     

12年连续施用秸秆和钾肥对土壤钾素含量和分布的影响

为探索潮土钾素肥力培肥的有效途径,本文通过设计不同施钾处理进行田间定位试验。结果表明,不同的处理对土壤速效钾、缓效钾含量的影响在不同的土层深度表现不同。连续12年施入秸秆、钾肥、秸秆加钾肥(年施K2O≥150kg hm-2)对培肥耕层土壤速效钾和缓效钾有积极促进作用,均能显著或极显著提高耕层土壤速效钾和缓效钾含量,但对耕层以下土壤培肥作用不明显。