施用腐植酸对夏玉米产量、氮素吸收及氮肥利用率的影响

为了探究腐植酸与无机肥料配施对夏玉米产量、氮素吸收及氮肥利用率的影响,于2014年始在河南省南阳市卧龙区英庄镇开展田间定位试验,共设置单施磷钾肥、常规施肥、常规施肥+3 000kg·hm~(-2)腐植酸、常规施肥减氮15%+3 000 kg·hm~(-2)腐植酸、常规施肥减氮30%+3 000 kg·hm~(-2)腐植酸等5个处理,分析不同氮肥运筹下夏玉米产量和氮肥利用的特征。结果表明,施用腐植酸可以有效改善夏玉米的农艺性状,提高夏玉米的产量,促进植株对氮素的累积和提高氮肥的利用率。其中,以常规施肥减氮15%+腐植酸处理效果最佳,与常规施肥相比,产量增加8.68%~12.96%,籽粒氮含量、籽粒氮累积量、地上部总氮累积量分别增加2.83%~3.92%、11.75%~19.74%、8.83%~19.41%,氮肥利用率增加52.00%~116.55%。因此,常规施肥减氮15%+3 000 kg·hm~(-2)腐植酸是本研究区域最佳的施肥模式,对实现现代农业生产的高产高效、资源节约和生态环境保护具有重要意义,是值得推荐的肥料运筹方式。     

集约经营对山核桃林地土壤腐殖质组分碳含量的影响

[目的]研究并探讨土壤腐殖质各组分碳含量的变化规律,为山核桃林地土壤管理提供理论依据。[方法]采集并分析山核桃林经营历史为5,10,15,20a的土壤样品的土壤腐殖质各组分碳含量,并与天然混交林(0a)进行比较。[结果]与天然山核桃—阔叶混交林(0a)相比,随着经营历史的延长,林地土壤腐殖质各组分碳含量的变化主要发生在表层(0—10cm),胡敏酸碳、富里酸碳和胡敏素碳含量均下降。与0a相比,集约经营5a后胡敏酸碳、富里酸碳和胡敏素碳含量分别下降了42.8%,23.9%和21.2%,而集约经营20a后,分别下降了45.3%,39.0%,32.3%。集约经营20a后,亚表层(10—30cm)土壤胡敏素碳含量上升了94.2%。[结论]集约经营降低了山核桃林地土壤表层和亚表层的胡敏酸碳和富里酸碳含量,同时也降低了表层土壤胡敏素碳含量,而提高了亚表层土壤胡敏素碳含量。     

森林生态系统中土壤有机质组分的固态13C核磁共振波谱表征

Forest management practices such as prescribed burning and thinning in forest ecosystems may alter the properties of soil organic matter (SOM).In this study,surface soils from field plots in the Bankhead National Forest,Alabama,USA,were used to investigate possible SOM transformations induced by thinning and burning.Elemental analysis and solid-state 13C cross polarization magic angle spinning nuclear magnetic resonance (13C CPMAS NMR) spectroscopy were used to characterize SOM fractions in whole soils,humic substances,and density fractions.Our data revealed that the changes in SOM fractions due to the repeated burning carried out in the forest ecosystem studied were involved mainly with alkyl C,O-alkyl C,and carbohydrate functional groups,implying that most prominent reactions that occurred involved dehydrogenation,de-oxygenation,and decarboxylation.In addition,burning and thinning might have also affected the distribution and composition of free and occluded particulate SOM fractions.The limited structural changes in SOM fractions suggested that low-intensity prescribed fire in the forest ecosystem studied will not create major structural changes in SOM fractions.     

Effect of humic substances on nutrient uptake by herbage and on production and nutritive value of herbage from sown grass pastures

The effect of humic substances on the nutrient uptake, herbage production and nutritive value of herbage from sown grass pastures was studied in six field experiments. Commercial humic substances were applied in combination with mineral fertilizer or slurry, either as a solution (HF liquid; 8·3 kg humic substances ha⁻¹) or incorporated into the mineral fertilizer (HF incorporated; 3·6 to 6·4 kg humic substances ha⁻¹). A series of cuts, ranging from two to five cuts, was taken during the growing season. The general response in herbage production to application of humic substances was an increase in herbage mass of dry matter (DM) at the first cut although this was only significant in two experiments for the HF incorporated treatment. Total herbage production of DM over the growing season, however, was similar for treatments with or without application of humic substances. The overall effect of HF incorporated and HF liquid on the herbage mass of DM at the first cut across the experiments was calculated using a meta-analysis technique and it was shown that there was a significant proportional increase of 0·14 ( P  <   0·05) with the HF incorporated treatment and a non-significant increase of 0·08 with the HF liquid treatment compared to the control treatment. The nutritive value of the herbage at the first cut was similar across all treatments. In general nitrogen, phosphorus and potassium uptake at the first grass cut was higher after application of humic substances but only in one experiment was this increase statistically significant.     

不同浓度腐殖酸对水培生菜生长的影响

以生菜为试验材料,对无土栽培营养液山崎配方和经验配方添加不同浓度腐殖酸,通过研究其对生菜生长性状(商品生物量、株高、根长、根重)、叶绿素含量、有机酸含量等的影响,探讨腐殖酸用于无土栽培营养液的可行性及其应用效果。结果表明:腐殖酸在较低的浓度水平下可以显著提高生菜的产量,降低生菜有机酸含量。腐殖酸可以作无土栽培营养液的配方成分使用。在山崎配方中添加适当浓度的腐殖酸(0.116%～0.348%)可以显著增加生菜的商品生物量、根重、根长和叶绿素含量。腐殖酸添加在在盐分浓度较高的经验配方Ⅱ时皆有不同程度的负作用。     

Effect of fulvic and humic acids on performance, immune response and thyroid function in rats

Effect of humic acid (HA) and fulvic acid (FA) on production parameters, immune response and thyroid function of rats were investigated in two experiments. First experiment: control or 0.1%, 0.2%, 0.4%, 0.8% HA- or FA-supplemented diets. Second experiment: control and 0.4% HA- or FA-supplemented diets. The feeding period lasted 26 days in both trials. No significant changes were observed in production parameters. Ovalbumine antibody titre of rats on HA- or FA-supplemented diets showed dose-dependent (at 0.4% supplementation) and significant (p < 0.05) increase (350 and 418% respectively) over the control (100%). Dose-related increase of plasma TSH (r = 0.99), and decrease of the T(4)/T(3) ratio (r = -0.97) was observed in FA-supplemented rats. Second experiment: both FA and HA stimulated the immune response by the 14th day (mean values: control: 685.79; FA: 1131.37; HA: 1055.6099) and 26th day (control: 544.31; FA: 1969.83; HA: 1600.00). No significant differences were noted with lymphocyte stimulation test. Diameter of the 'B'-dependent lymphoid tissues in the ileum and spleen were significantly (p < 0.05) larger in both the FA- and HA-treated animals. Humic acid and FA supplementation resulted in strong humoral immune stimulation. Our data also indicate that FA content is responsible for the mild hypothyroid effect of humic substances.     

黑液制备的腐植酸液肥和调理剂的棉花田间应用研究

为了给黑液实现资源化利用提供依据,在新疆进行了黑液腐植酸产品的田间试验,设计了3个处理,采用棉花定点定株方法调查其生理指标,并测定其生化指标,研究了它们对棉花的生长、产量和抗旱能力的影响。结果表明,在滴灌中应用腐植酸液肥,与常规固体肥料相比可明显促进棉花在各生育期的生长,能增加蕾、花和铃的数量,并且延长成熟时间,作物不易早衰。同时液肥还可提高棉花的经济性状,能够显著增加籽棉的产量,增产率可达12.3%。在棉花上使用该腐植酸产品后可降低叶片的蒸腾速率,提高叶片的保水能力和CAT活力,从而明显增强棉株的抗旱能力。黑液腐植酸产品对棉花具有良好的促长、增产和抗旱效果。     

腐殖酸对植烟土壤和烟草影响的研究进展

本文综述了腐殖酸对植烟土壤和烟草各方面的影响,揭示出腐殖酸能够改善植烟土壤性状,提高烟叶品质,同时,对烟草的安全性和抗逆性也有一定的作用。并在此基础上对今后的研究方向进行了展望,旨在为腐殖酸在烤烟生产上的推广应用提供理论依据。     

Clay dispersion and its relation to surface charge in a paddy soil of the Red River Delta,Vietnam

Dispersion is an important issue for clay leaching in soils. In paddy soils of the Red River Delta (RRD), flooding with fresh water and relatively high leaching rates can accelerate dispersion and the translocation of clay. For the clay fraction of the puddled horizon of a typical paddy soil of the RRD, the effect of various cations and anions as well as humic acid (HA) at different pH values on the surface charge (SC) were quantified and the dispersion properties were determined in test tubes and described by the C₅₀ value. In the <2 µm fraction, dominated by illite, the proportion of 2:1 vs. 1:1 clay minerals is 5:1. The organic‐C content of the clay fraction is 2.2%. Surface charge was found to be highly pH‐dependent. At pH 8 values of –32 and at pH 1 of –8 mmol_c kg^–1 were obtained. Complete dispersion was observed at pH > 4, where SC is > –18 mmol_c kg^–1. The flocculation efficiency of Ca strongly depends on the pH. At pH 4, the C₅₀ value is 0.33, 0.66 at pH 5, and 0.90 mmol L^–1 at pH 6. At pH 6, close to realistic conditions of paddy soils, the effect of divalent cations on the SC and flocculation decreases in the order: Pb > Cu > Cd > Fe^II > Zn > Ca > Mn^II > Mg; Fe^II was found to have a slightly stronger effect on flocculation than Ca. An increase in concentrations of Ca, Mn^II, and Mg from 0 to 1 mmol L^–1 resulted in a change in SC from –25 to approx. –15 mmol_c kg^–1. In comparison, the divalent heavy‐metal cations Pb, Cu, Cd, and Zn were found to neutralize the SC more effectively. At a Pb concentration of 1 mmol L^–1, the SC is –2 mmol_c kg^–1. From pH 3 to 5, the dispersion of the clay fraction is facilitated rather by SO than by Cl^–, which can be explained by the higher affinity of SO to the positively charged sites. With an increase of the amount of HA added, the SC continuously shifts to more negative values, and higher concentrations of cations are needed for flocculation. At pH 3, where flocculation is usually observed, the presence of HA at a concentration of 40 mg L^–1 resulted in a dispersion of the clay fraction. While high anion concentrations and the presence of HA counteract flocculation by making the SC more negative, Fe^II and Ca (C₅₀ at pH 6 = 0.8 and 0.9 mmol L^–1, respectively) are the main factors for the flocculation of the clay fraction. For Fe^II and Ca, the most common cations in soil solution, the C₅₀ values were found to be relatively close together at pH 4, 5, and 6, respectively. Depending on the specific mineralogical composition of the clay fraction, SC is a suitable measure for the determination of dispersion properties and for the development of methods to keep clay particles in the soil in the flocculated state.     

黑液腐殖酸液体肥料对棉花生长及土壤理化性质的影响

【目的】探讨黑液腐殖酸液体肥料(Humic acid liquid fertilizer,HALF)对棉花生长及土壤性质的影响,为其在棉花生产中的应用提供参考依据。【方法】通过网室-盆栽试验,以不施肥(CK)为对照,研究施用A型、B型和C型3种HALF肥料(HALF-A、HALF-B、HALF-C),N、P、K配施(NPK处理)以及N、P、K与HALF-C配施对棉花地上部干物质积累、养分吸收和土壤养分含量等的影响。【结果】与NPK处理相比,施用HALF肥料能使棉花地上部干物质积累量提高10.0%~65.8%,其中以HALF-C与NPK配合施用处理棉花生长最好。与NPK处理相比,施用HALF和HALF-C+NPK肥料使棉花地上部氮吸收量增加24.3%~101.4%,磷吸收量增加58.3%~100%,钾吸收量增加10.1%~56.2%,但3种HALF肥料效应不同。施用合适的HALF肥料能显著降低土壤pH0.06~0.11,提高土壤有机质和土壤速效养分含量。【结论】3种HALF肥料均能促进棉花生长,提高土壤养分含量,其中以HALF-C应用效果最好。