腐殖酸对钾在褐土中迁移和转化的影响

采用室内土柱实验研究了腐殖酸与钾共施时腐殖酸对钾在褐土施肥点附件微域中迁移和形态转化的影响。研究结果表明,与单施KCl处理相比,共施腐殖酸没有明显改变肥料钾在褐土中的迁移距离,在培养7天时增加了肥际微域中的水溶性钾含量,而在培养28天时则降低了其含量;共施腐殖酸明显增加了交换性钾含量以及在土壤中的迁移量,但减少了非交换性钾的含量和迁移量。说明共施腐殖酸减少了土壤晶格对钾离子的固定,提高了外源钾在褐土中的有效性。     

长期施肥褐土有效磷对磷盈亏的响应

【目的】研究长期施肥条件下土壤磷素供应能力、累积状况与土壤有效磷变化速率,阐明土壤磷素累积与土壤有效磷的响应关系,为黄土高原旱作农业区科学施用磷肥提供理论依据。【方法】以农业部寿阳旱作农业示范区褐土肥力与肥料长期定位试验为研究平台,选择试验中9个处理进行研究分析,分别为不施肥处理(CK)、4个单施无机肥水平处理(N_1P_1、N_2P_2、N_3P_3、N-4P_4),3个有机无机肥配施水平处理(N_2P_1M_1、N_3P_2M_3、N-4P-2M_2)单施有机肥处理(N_0P_0M-6)。以5年一个周期测定土壤0-20 cm有效磷含量,明确土壤有效磷的变化规律。计算玉米收获后植株生物量以及测定磷含量得出作物携出量与磷素年累积量,分析不同施肥处理下土壤磷素盈亏与土壤有效磷的变化特征。【结果】长期不施用磷肥情况下,土壤磷素一直处于亏缺状态,有效磷年均下降速率为0.02mg/(kg·a)。单施无机肥后,随着磷肥投入量的增加,土壤有效磷随之增加,N_1P_1、N_2P_2、N_3P_3、N_4P_4处理年均增速分别为1.04、1.08、1.70和2.13 mg/(kg·a)。有机无机配施处理土壤有效磷普遍高于单施化学磷肥处理含量,N_2P_1M-1、N_3P_2M-3、N_4P_2M_2处理年均升高速率分别达1.70、3.73和4.72 mg/(kg·a)。单施高量有机肥N_0P_0M_6处理土壤中有效磷增速最高,年均升高5.63 mg/(kg·a)。长期不施肥导致土壤磷素亏欠,土壤中每亏缺P 100 kg/hm~2,土壤中有效磷含量平均降低0.5 mg/kg。施用无机肥条件下,土壤每累积P 100 kg/hm~2,土壤中有效磷含量可以平均提高4.3 mg/kg。有机无机配施有协同作用,其土壤P每累积100 kg/hm~2,土壤有效磷含量平均提高9.1 mg/kg。N_2P_1M_1处理为推荐施肥处理,即每年投入P_2O_5 65 kg/hm~2,后土壤有效磷增加最多,土壤每累积P100 kg/hm2,土壤中有效磷含量平均提高17.1 mg/kg。【结论】土壤有效磷随土壤磷素盈余而变化,同时与磷素投入量密切相关,当P_2O_5;每年投入量为37.5~65 kg/hm~2时基本可以满足作物生长需求磷肥当季利用率较高,磷素在土壤中累积量较少。当P_2O_5;每年投入量达到112 kg/hm~2,后会造成磷素在土壤中大量累积不仅作物产量对磷肥几乎没有响应还会对农田环境产生危害。     

石灰性褐土中磷锌镉相互作用对其有效性的影响

采用室内培养的方法,研究了石灰性褐土中磷、锌、镉相互作用对土壤中磷、锌、镉有效性的影响。结果表明：（1）磷锌共同培养时,施锌提高了土壤速效磷含量,且随培养时间的延长而降低。在相同锌浓度处理下,土壤中的有效锌含量随施磷量的增加而增加,不同锌浓度处理下,有效锌含量随土壤培养时间的延长而显著降低。（2）磷镉共同培养时,施镉对土壤速效磷含量影响不明显;施磷降低了有效镉含量,但效果不显著;且都随时间的延长而降低。（3）锌镉共同培养时,在培养的前30d,土壤中有效锌含量随施镉浓度增加而降低,但在30d后,有效锌含量有增加的趋势。土壤中有效镉含量在不同锌-镉处理下随培养时间变化有较大差异：在Cd3处理下,加入高浓度锌后显著降低土壤有效镉含量;Cd30处理下,在培养前30d,锌的施入对土壤中有效镉含量影响不明显,但30d以后,土壤有效镉含量随施入锌浓度的增加而显著降低。说明两者的竞争机制随时间的延长发生变化,且施锌能明显降低镉的毒性。     

山西石灰性褐土的磷、锌关系及其对玉米幼苗生长的影响

为定量探讨石灰性土壤中的磷、锌关系及其对玉米幼苗生长的影响,运用数学模型,在土壤pH为8.12、有效磷为2.56ppm、有效锌为1.08ppm的山西石灰性褐土上进行盆栽试验。研究结果表明:(1)土壤磷、锌营养供应协调时,玉米幼苗对磷、锌的吸收具有显著的相互促进作用,否则,磷、锌相互拮抗。(2)施磷能促进土壤锌的解吸,增加土壤有效锌的含量。(3)土壤中的磷酸锌沉淀并不是引起作物缺磷或缺锌的主要原因,而可能是由于磷、锌营养平衡失调而引起的发生在根内的一种生理性障碍。     

长期施肥褐土不同磷组分对磷素盈余的响应

  【目的】  研究褐土区玉米田长期不同磷源投入对土壤磷素形态和磷素累积的影响，通过对不同磷组分与磷素盈余之间进行相关性分析，研究不同施肥措施对土壤磷素形态转化的影响，为探索合理的磷肥调控措施，促进土壤中磷素向作物易于吸收的水溶态和碳酸氢钠溶解态转化，提高磷素利用效率提供依据。  【方法】  试验依托始于1992年位于山西省寿阳县北坪旱塬上的长期定位试验。9个施肥处理包括:无肥对照 (CK)、N₁P₁、N₂P₂、N₃P₃、N₄P₄、N₂P₁M₁、N₃P₂M₃、N₄P₂M₂、N₀P₀M₆，其中N₁、N₂、N₃、N₄分别为尿素N 60、120、180、240 kg/hm2，P₁、P₂、P₃、P₄分别为过磷酸钙P 16、33、49、66 kg/hm2，M为腐熟厩肥，M₁、M₂、M₃、M₆分别折合为施P量14、28、42和83 kg/hm2。1992—2016年，收获后取0—20 cm耕层土壤样品，分析土壤磷素形态及盈余量，并计算不同形态磷素与磷盈余量之间的相关性。  【结果】  连续施肥25年后，土壤磷组分发生了不同的变化，不施肥处理除H₂O-Pi、Residual-P外，各形态磷较试验初均有降低。施用无机肥各处理主要增加了土壤中HCl-P含量，以N₄P₄处理提高幅度最大，比试验初提高了127.7%。有机肥投入可以显著提高土壤中的活性磷含量，高量施用有机肥后，H₂O-P总含量较试验初提高了8倍之多，NaHCO₃-Pi年增加速率为11.50 mg/(kg·a)。不同施肥各处理土壤磷素盈余量为N₀P₀M₆ > N₃P₂M₃ > N₄P₄ > N₄P₂M₂ > N₃P₃ > N₂P₂ > N₂P₁M₁ > N₁P₁ > CK。磷素盈余是土壤磷组分变化的重要影响因素，各形态磷组分对磷素累积量响应大小为NaHCO₃-Pi > NaOH-Pi > HCl-P > NaHCO₃-Po > Residual-P > H₂O-Po > NaOH-Po > H₂O-Pi。  【结论】  长期施肥使土壤各组分磷素含量发生了显著变化，有机无机肥配施有利于土壤中活性磷的转化，过量施磷导致磷素在土壤中大量盈余，高量施用有机肥磷素盈余量最大。当以无机肥投入时，施用过磷酸钙P 33 kg/(hm2·a)基本可以满足作物生长发育的要求。当有机无机肥配施时，施用过磷酸钙P 16 kg/(hm2·a)，配施厩肥P 14 kg/(hm2·a) 时，土壤磷素盈余量最小。     

外源腐殖酸对三种土壤无机磷组分的影响

磷是植物生长所需的大量元素之一,然而磷肥的当季利用率一般只有10%~25%,75%~90%的磷肥以不同形态的磷酸盐积累在土壤中[1]。因此,磷在土壤中的存在形态,以及施肥对磷素形态的影响一直受到人们的广泛关注[2~5]。植物直接吸收利用的磷大部分为无机磷[6],已有研究表明,有机酸能明显提高土壤有效磷含量[7~10],而有效磷含量的增加与土壤中无机磷形态的变化密切相关。面对当前土壤中累积的大量磷元素,而植物可利用的磷却十分低的现象,如何激活并利用土壤中难溶态磷一直是土壤研究工作者高度关注的问题。腐殖酸类物质作为一种潜在的有机资源,越来越受到土壤学者的关注[11,12],特别是腐殖酸对磷肥增效作     

不同处理褐煤腐殖酸对磷吸附特性的研究

采用吸附等温线的试验方法,研究了平衡溶液中磷浓度、反应时间及介质pH对不同处理的2种褐煤腐殖酸吸附磷的影响及其规律性。结果表明:在试验pH范围内,pH的升高减缓了吸附反应进行的速度,对于未经硝酸处理的样品S1,在pH为4.7时,吸附量和分配系数有一最大值,而样品S2,随着pH的升高,吸附量和分配系数一直减小;经硝酸处理后,样品对磷的吸附能力降低,一定条件下其单位吸附量仅为处理前的5.33%。适宜的固液比例可提高2个不同处理供试样品对磷的单位吸附量,其等温吸附规律可用Langmuir方程来加以描述;其吸附动力学用Elovich方程描述最佳。     

腐殖酸和改性木质素对土壤磷有效性影响的研究进展

如何减缓土壤中磷肥的老化、固定以及如何重新利用土壤中潜在磷素,对解决磷在农业生产中所引起的经济、环境和资源问题有很重要的意义。本文结合国内外已有成果和最新研究进展,综述了腐殖酸和改性木质素在提高磷素利用率、降低磷素环境压力等方面的应用和机理研究,针对目前的研究现状,指出了目前研究中面临的一些问题以及今后研究的热点。     

氮对磷在潮土中迁移与转化的影响

通过土柱培养试验对磷肥在潮土中的迁移转化和其受不同氮肥的影响进行了研究。结果表明:培养60d后,单施磷酸二氢钙处理(MCP)距施肥点0～2 mm土壤pH值从8.29降至7.82,土柱中水溶性磷(W-P)、Ca_2-P和Ca_8-P分别为7.4、18.6和9.0 mg,分别占土壤无机磷增量的13.0%、32.7%、15.8%。配施尿素处理(MCP+U)和配施硫酸铵处理(MCP+AS)均较MCP降低了距施肥点0～2 mm土壤的pH值,提高了W-P的迁移距离和Ca_2-P与Ca_8-P的分布范围。MCP+U土柱中W-P、Ca_2-P分别下降63.5%(2.7 mg)、65.6%(6.4 mg),Ca_8-P则提高176.7%(24.9 mg),而MCP+AS土柱中W-P、Ca_2-P分别提高100%(14.8 mg)、32.3%(24.6 mg),Ca_8-P则下降42.2%(5.2 mg)。相比MCP,MCP+AS提高了磷肥的速效性,对于作物养分亏缺时及时供给磷素更为有利;MCP+U的磷肥速效性有所降低,对于磷肥供作物中长期利用效果更显著。     

磷含量和秸秆添加量对褐土锌吸附—解吸的影响

采用室内培养的方法,通过人为添加不同量的玉米秸秆和磷,研究不同含量磷和作物秸秆对土壤锌吸附—解吸的影响,以探讨磷—锌在土壤中的交互作用机制。结果表明:低锌(Zn10:添加Zn2+浓度为10 mg L-1)条件下,土壤对Zn2+的吸附量随土壤速效磷含量的增加而逐渐降低,表明在石灰性土壤中,随磷含量的增加提高了土壤锌的有效性;而Zn2+的解吸量随土壤中磷含量的增加先升高后降低,添加Zn2+浓度为80 mg L-1(Zn80)条件下,土壤对Zn2+的吸附量明显大于Zn10条件下。土壤中添加不同秸秆量对不同浓度Zn2+吸附时,低锌(Zn10)处理下,在相同磷含量情况下,土壤对Zn2+的吸附量随秸秆添加量的增加而减少,而土壤对Zn2+的解吸量随秸秆量的增加而增加。在不同磷水平下,不同秸秆添加量对Zn2+的吸附趋势差异较大。高锌(Zn80)处理下,土壤对Zn2+的吸附量在不同秸秆量处理下趋势大致相同,且Zn2+吸附量随磷含量的提高先升高后降低;在同一磷水平下,土壤对Zn2+的吸附趋势和Zn10时相似。利用KNO3进行解吸Zn2+时,不添加秸秆和低量秸秆处理变化趋势相同,均在添加磷量为360 mg kg-1时解吸量达到最大,分别为363.5 mg kg-1、424 mg kg-1,而高量秸秆处理下,Zn2+解吸量随磷含量的增加先升高后降低。     

长期试验条件下褐土地力贡献率的演变特征及其影响因素分析

褐土是中国小麦与玉米产区的主要土壤类型之一,土壤地力贡献率显著影响作物产量。为了探明我国褐土土壤地力贡献率演变特征,科学合理地指导褐土土壤管理和施肥,分析了25年(1988~2013年)来长期施肥条件下褐土小麦和玉米地力贡献率的演变特征,并运用通径分析对影响土壤地力贡献率的各个因素进行了分析,结果表明:褐土区小麦和玉米产量的土壤地力贡献率分别为51.6%和54.5%,我国东北一年一熟制玉米褐土,耕地地力逐步下降,经过大约9年和6年明显下降,稳定在40%~60%左右,我国华北一年二熟制小麦褐土,耕地地力逐步下降,经过10年左右的下降,基本稳定在12%~44%左右。通径分析进一步证明,土壤有效磷、速效钾和土壤有机质对玉米地力贡献率影响最大,土壤有效磷贡献率最高,说明土壤有效磷、速效钾以及土壤有机质是褐土区基础地力的主要影响因素,是褐土区土壤地力主要评价指标。     

Riparian reforestation with a single exotic species restores soil aggregation and porosity but not humic substances

A degraded riparian area in the Uberaba River basin (Brazil) was restored by local landowners using a monoculture of the exotic species Syzygium cumini (L.) Skeels over 15 years. To assess this riparian restoration, we compared this experimental site (ES ) with a disturbed site (DS ) and a preserved site (PS ) with regard to soil organic matter, humic and fulvic acids (HA and FA ), glomalin, soil aggregation and porosity. The results did not show significant differences between ES and PS with regard to soil aggregation and porosity. The cation exchange capacity and the HA and FA contents of ES were significantly different from those in PS and DS . Whereas the HA content of ES was less than that in PS , FA was significantly increased. The order of aromatic composition of humic substances by site was PS  > ES  > DS and contrasted with the aliphatic composition, which was DS  > ES  > PS . A principal component analysis based on all variables demonstrated that ES was closer to PS than to DS but that there was no overlap among sites, as PS was driven by humic aromatic substances and the experimental site by fulvic and aliphatic compounds. We concluded that there was a functional recovery of ecosystem services related to soil aggregation and porosity, but the qualitative differences in organic matter formation between the restored and preserved sites were not consistent with ES being fully restored.     

腐殖酸对磷在红壤中有效性的影响

An investigation was conducted to study the effect of humic substance （HS） on the phosphorus （P） solubility in acidic soil. The soil （2.5 g）, HS （0, 0.5, and 2.5 g）, and P as monocalcium phosphate （0.31 and 1.25 g P kg^-1 soil） were mixed with 50 mL distilled water and two different sequences of adding HS and P were used. The results indicated that the P concentration in water and 0.01 mol L-1 CaCl2 solution increased with increasing amounts of humic substance. The concentrations of Fe and Al were also increased. However, Olsen P decreased with increasing amount of humic substance. Water-soluble P concentrations from P rates at 0.31 and 1.25 g P kg^-1 soil in the treatment with 0.5 g （2.5 g） humic substance addition were 360% and 70% （500% and 90%） higher, respectively, than those in the treatment with no humic substance addition. P extracted by 0.01 mol L^-1 CaCl2 in the treatments with 0.5 and 2.5 g humic substance addition was increased by 400% and 540%, respectively, compared with that in the treatment without humic substance at the rate of 0.31 g P kg^-1 soil, while the corresponding P concentrations were increased by 80% and 90% at the rate of 1.25 g P kg^-1 soil. The order of mixing humic substance and phosphate did not significantly affect desorbed P and labile P extracted with CaCl2.     

河南中西部典型褐土在系统分类中的归属

选取位于河南中西部褐土土类的7个典型单个土体作为研究对象,通过土壤剖面形态特征和理化性质的分析,确定了它们在中国土壤系统分类中的位置.按照《中国土壤系统分类(第三版)》诊断标准,供试剖面中诊断出包括黏化层、钙积层、雏形层、氧化还原特征、温性土壤温度状况、半干润土壤水分状况等诊断层和诊断特性,7个剖面中,4个划归淋溶土纲...     

潮褐土上蔬菜产量和土壤各形态磷变化对长期过量施磷的响应

【目的】研究长期连续过量施用磷肥下蔬菜的产量响应、磷肥去向及土壤各形态磷库的动态变化。 【方法】在太行山山前平原典型潮褐土上,连续进行11年21茬露地蔬菜的长期定位肥料试验,P₂O₅年施用量设0 (P0)、360 (P1)、720 (P2)、1080 (P3)、1440 (P4) kg/hm2共5个处理,分别测定每茬蔬菜产量及各年土壤不同形态磷素含量。 【结果】与不施磷肥处理比较,单季P₂O₅用量180、360、540、720 kg/hm2均显著增加大白菜、菜豆产量,不同磷肥用量间蔬菜产量均无显著差异。P₂O₅年用量为360、720、1080、1440 kg/hm2,土壤年盈余磷为41.2～478.7 kg/hm2,积累率为26.2%～76.1%。与基础土比较,随着磷肥用量的增加,土壤有效磷、全磷、无机磷总量及无机磷中的Ca₂-P、Ca₈-P、Al-P、Fe-P含量均呈显著增加趋势,无机磷中的O-P、Ca₁₀-P含量无显著变化。P₂O₅年用量为720、1080、1440 kg/hm2处理土壤的有效磷年均增加量为2.3、4.2、5.0 mg/kg;土壤有效磷增加量与磷盈余量呈显著直线正相关关系,土壤磷素每盈余100 kg/hm2,有效磷、Ca₂-P、Ca₈-P、Al-P、Fe-P 含量分别增加1.13、2.41、15.27、4.14、1.37 mg/kg。随着土壤磷盈余量和施肥年限的增加,有效磷占全磷比重、Ca₂-P、Ca₈-P、Al-P占无机磷比重逐渐增加。 【结论】施用磷肥显著增加大白菜和菜豆产量,过量施用磷肥蔬菜产量无显著变化;土壤磷素处于盈余状态下,随着磷肥用量的增加或种植年限的增加,土壤积累磷的有效性随之增加。基于蔬菜对磷肥产量响应和土壤磷素收支表观平衡状况,露地大白菜P₂O₅推荐用量180 kg/hm2,菜豆270 kg/hm2。     

褐土机械组成空间变异等级次序地统计学估计

采用2 m×2 m均匀栅格取样方式和等级次序地统计学方法，研究了面积为200 m²褐土耕层土壤机械组成的空间变异性。统计特征量表明褐土耕层土壤的机械组成存在高度空间变异性，样本数据不服从正态分布和对数正态分布，无法直接应用普通克里格法研究其空间变异规律。采用重叠移动窗口统计数据可削弱局部偏差值带来的影响，经等级次序标准化转换后用半方差函数分析其等级次序空间结构，再根据普通克里格法对标准化等级次序空间进行估值。对所得的标准等级次序估计值用中位值模型进行逆转换，较清晰地阐明了褐土农田机械组成带状各向异性的空间分布规律。     

Solubilization of iron by water‐extractable humic substances

The capability of water‐extractable humic substances (WEHS) to solubilize Fe from sparingly soluble Fe‐hydroxide was studied. Addition of WEHS (1.7 mmol organic C l^—1) to a dialysis tube containing labeled insoluble Fe‐hydroxide caused an increase in the amount of ⁵⁹Fe measured in the external solution. The humic fraction was also able to solubilize Fe from soil samples, with levels comparable to those obtained using a solution containing 100�μM DTPA. By measuring the amount of ⁵⁹Fe eluted from soil columns pre‐loaded with ⁵⁹Fe‐WEHS it was possible to evaluate the mobility of Fe complexed to the humic molecules. The recovery of ⁵⁹Fe varied from 2% to 25% in respect to the soil type used. The ability of Fe‐WEHS to serve as an Fe source for the phytosiderophore hydroxy‐mugineic acid (HMA) was also analyzed. The removal of ⁵⁹Fe from the Fe‐WEHS complex by HMA was demonstrated by adding the phytosiderophore to a dialysis tube containing the ⁵⁹Fe‐WEHS complex. The observations suggested a ligand exchange between the phytosiderophore and the humic fraction. The results indicate that WEHS is able to increase the amount of Fe present in the soil solution, possibly by forming mobile complexes with the micronutrient. These complexes could act as easily available Fe sources in Fe acquisition processes by both monocot and dicot plants, playing an important role particularly in soils with low available Fe.     

Labile soil organic matter as a potential nitrogen source in golf greens

The loss of fertilizer N from golf greens can be high depending upon management (irrigation schedule, N source, rate and timing of fertilizer application) as well as soil conditions. Although soil organic matter (SOM) is acknowledged as a major source of N and other nutrients, its potential as an N source seems to be neglected in the management of golf greens. The susceptibility of SOM to degradation is one indication of how active a role SOM plays as a nutrient source. An extraction method developed by Olk et al. [Geoderma 65 (1995) 195] distinguishes humic acid fractions by their binding to dominant stabilizing soil cations and separates them into calcium-bound (CaHA) and non calcium-bound or mobile (MHA) fractions. Mobile humic acid is a relatively young, N-rich HA fraction that does not appear to form stable complexes with Ca. The MHA could therefore play a greater role in nutrient availability than CaHA. We determined C and N distributions within SOM extracted from these two HA fractions in 11 golf greens ranging in age from 4 to 28 yr. Because SOM in golf greens is recently formed, and MHA is an N-rich fraction representing an early stage of SOM evolution, we hypothesized that the MHA fraction would account for a larger proportion of soil organic N than CaHA. The amounts of both HA-C and HA-N increased significantly with green age. MHA accounted for a larger proportion (20-27%) of total soil C than CaHA-C (8-14%). MHA was also enriched in N compared to CaHA with consistently smaller C-to-N ratios. Thus, the greater abundance of MHA and its higher N concentration accounted for a larger proportion of soil organic N (24-45%). The equivalence of MHA-N ranged between 250 kg N ha⁻¹ for a 4 yr-old green and 775 kg N ha⁻¹ for a 21 yr-old green. Thus, soils of established greens contain significant quantities of labile SOM rich in N that could through mineralization supply part of the fertilizer N requirement of turf grass. A greater understanding of the dynamics of this resource is needed if we are to manage golf greens for optimal use without negative consequences to the environment.