不同氮肥处理对污染红壤中铜有效性的影响

通过室内培养试验,发现不同氮肥处理对污染红壤中铜有效性有显著影响。在培养前期(0~15 d),施用尿素显著降低了红壤水溶态铜和有效态铜含量,而施用硫酸铵和硝酸钙则显著提高了水溶态铜含量,且硝酸钙的作用显著大于硫酸铵,但这两种氮肥对红壤有效态铜含量影响较小;培养60 d后,尿素对该红壤两种形态铜的抑制效应逐渐转为正效应,且硫酸铵的促进作用更为显著;硝酸钙对红壤两种形态铜的促进作用不如尿素。氮肥的施用量对两种形态铜也具有显著影响。同一施氮水平下,水溶态铜含量和有效态铜含量在不同氮肥处理间均达显著差异(硫酸铵>尿素>硝酸钙)。不同氮肥影响红壤铜有效性的主要机制是土壤pH的变化,红壤水溶态铜和有效态铜含量均与pH呈极显著负相关。     

不同氮肥种类和用量对川西蒙山茶品质的影响

利用盆栽试验研究了尿素、硫酸铵、硝酸铵、碳酸氢铵和硝酸钙5种氮肥和用量对川西蒙山茶品质的影响。结果表明:肥料种类、肥料用量以及肥料种类与用量的交互作用对茶叶主要品质指标(可溶性糖除外)的影响极显著;不论施用何种氮肥,茶叶中的茶多酚、儿茶素和咖啡碱含量都有极显著的增加;各种氮肥用量为4g/盆时,茶多酚、儿茶素和咖啡碱含量较高;与施用其他种类的氮肥相比,尿素能极显著地提高茶叶中儿茶素和氨基酸的含量。施用硝态氮将能显著提高茶叶中硝酸盐和亚硝酸盐的含量,但随着硝态氮用量的增加,硝酸盐和亚硝酸盐的含量没有显著变化,而铵态氮和酰胺态氮对茶叶硝酸盐和亚硝酸盐含量基本没有影响。综合考虑春夏秋三季茶叶的品质,若单施一种氮肥,尿素最为合适,施用量为8g/盆左右。     

不同形态氮肥对磷肥生物有效性的影响

利用盆栽试验研究了潮土中不同形态氮肥对磷肥生物有效性的影响。结果表明:不同形态氮肥处理均有抑制油菜生长初期磷素累积的作用,氯化铵处理抑制作用最突出,其次是尿素,再次是硫酸铵、硝酸铵和硝酸钙处理;油菜生长后期不同形态氮肥处理均逐渐显著促进油菜的磷累积,但氯化铵处理的促进作用仍然低于其它氮肥处理,这与不同形态氮肥处理对油菜生长的影响较一致。土壤有效磷含量受不同形态氮肥处理影响较小,而水溶性磷含量因施用不同形态氮肥均表现显著地下降,氯化铵和硫酸铵处理使土壤水溶性磷下降较多,硝酸铵、硝酸钙和尿素处理使土壤水溶性磷下降较少。     

不同氮肥对潮土中磷肥转化的动态影响

利用室内土培试验研究了不同氮肥对潮土中磷肥转化的动态影响。结果表明，除硝酸铵，不同氮肥均显著降低土壤有效磷含量，其中以硝酸钙和尿素处理作用最显著；不同氮肥均显著降低土壤水溶性磷含量，但硝酸铵的作用显著小于其他氮肥；各氮肥处理在培养15d时，土壤水溶性磷含量差异最显著，硝酸钙和尿素处理的土壤水溶性磷含量有小于氯化铵和硫酸铵处理的趋势，但随着时间延长，除硝酸铵外，各氮肥处理间差异不大。     

硫酸铵与尿素配比对土壤氮素形态、小油菜产量及氮素吸收的影响

为筛选硫酸铵与尿素的最佳配比,提高小油菜产量和氮肥利用率,本研究通过盆栽试验和大田小区试验,设置不施氮肥处理（CK）以及在同等氮肥施用量条件下6个硫酸铵与尿素配比：100%尿素（T1）、10%硫酸铵+90%尿素（T2）、20%硫酸铵+80%尿素（T3）、40%硫酸铵+60%尿素（T4）、80%硫酸铵+20%尿素（T5）和100%硫酸铵（T6）,测定分析不同施肥处理对土壤氮素形态、脲酶活性、小油菜养分吸收、产量和氮肥农学效率的影响。结果表明,随着硫酸铵配比增加,土壤pH值降低,全氮、碱解氮、铵态氮、硝态氮含量增加;微生物量氮含量呈现先增加后降低的趋势,其中T3处理最高;与T1处理相比,土壤脲酶活性在T2和T3处理下显著降低。与CK处理相比,施肥处理盆栽和大田试验小油菜的株高、根长、鲜重均显著增加,且随着硫酸铵配比增加呈先增加后降低的趋势,其中T3处理增幅最高,较T1处理平均增产36.9%,氮肥农学利用率平均提高84.9%;与T1处理相比,T3处理显著降低了小油菜硝酸盐含量。综上所述,20%硫酸铵+80%尿素配比有利于增加土壤氮素及微生物量氮含量,提高小油菜产量和品质,有效提升了氮肥农学利...     

氮肥对油菜根-土界面镉迁移及镉组分变化特征的影响

利用盆栽试验研究了不同形态氮肥对镉污染土壤油菜根土-界面pH、油菜生长、镉迁移及镉组分变化特征的影响.结果表明,不同形态的氮对油菜地上部Cd积累有显著的影响,施用铵态氮肥可以显著提高油菜地上部Cd含量,而施用硝态氮肥则对地上部Cd含量没有明显的影响.铵态氮肥能显著降低油菜根际pH,使得油菜根际残渣态、碳酸盐态和铁锰结合态Cd强烈活化,促使这三种形态Cd向交换态转换,从而增加了Cd的生物有效性.     

不同形态氮肥对棉花15N 回收率和产量的影响

采用盆栽试验,保证土壤水分含量不低于田间持水量的60%,在等量施氮条件下,研究尿素、硫酸铵、硝酸钙3 种氮肥在播前、蕾期、初花期施用对棉花15N 回收率和产量的影响,旨在为棉花氮肥合理施用提供理论依据。结果表明,在3 个施肥时期单施尿素、硫酸铵籽棉产量显著优于单施硝酸钙,分别高15.3%、14.0%。不同种类氮肥组合硫酸铵+ 尿素+ 硝酸钙、硫酸铵+ 硝酸钙+ 硝酸钙籽棉产量最高,分别比单施尿素高10.5%、9.0%。基肥15N 回收率28.8% ～ 32.2%,硫酸铵> 尿素> 硝酸钙,蕾期追肥15N 回收率57.2% ～ 73.2%,硝酸钙> 尿素> 硫酸铵,初花期追肥15N 回收率71.8% ～ 82.7%,硝酸钙> 硫酸铵> 尿素。本试验条件下,硫酸铵基施,蕾期施用尿素或硝酸钙,初花期施用硝酸钙,增加了单株成铃数,获得了较高的籽棉产量和氮肥回收率。     

不同氮肥对油菜生长和养分吸收的影响

利用盆栽试验研究了潮土中不同氮肥对油菜生长和N、P、K、Ca、Mg等养分吸收的影响,结果表明:不同氮肥对油菜生长和养分吸收的影响以生长初期(5周时)差异最显著。生长初期,除硝酸钙外,不同氮肥均显著抑制油菜的生长,氯化铵>硫酸铵、尿素>硝酸铵;对N、K、Ca、Mg的吸收,氯化铵、硫酸铵和尿素表现显著的抑制作用,且氯化铵和尿素有大于硫酸铵的趋势,而硝酸钙表现显著的促进作用,硝酸铵大多情况下作用不明显;对P的吸收,各氮肥均表现显著的抑制作用,且氯化铵>尿素>硫酸铵、硝酸铵和硝酸钙。但随着时间推移,各氮肥最终均显著促进油菜生长和养分吸收,且不同氮肥的差异也逐渐减小。     

油菜连作及施用堆肥对土壤镉赋存形态和生物有效性的影响

通过温室土培盆栽试验,研究了重金属镉污染土壤上连作油菜及施用堆肥对土壤中镉赋存形态及生物有效性的影响。结果表明：（1）在油菜连作体系下,施用堆肥显著降低油菜地上部镉含量。施用堆肥改变了土壤镉赋存形态,显著降低土壤易溶态和碳酸盐结合态镉含量而增加土壤铁锰氧化物结合态镉含量,从而降低土壤镉的生物有效性。（2）在相同堆肥处理下,种植两茬油菜后的土壤易溶态和碳酸盐结合态镉含量与不种植油菜的处理相比显著降低;而土壤硫化物及有机结合态镉含量较对照有所上升,种植油菜对土壤铁锰氧化物结合态镉和残渣态含量影响不显著,但是不同积累镉能力油菜朱苍花籽和川油Ⅱ-93之间对土壤镉形态的影响差异不显著。     

秸秆炭化后还田对不同镉污染农田土壤中镉生物有效性和赋存形态的影响

通过土壤培养试验和生物盆栽试验,研究不同镉污染土壤上作物秸秆炭化后还田对不同镉污染土壤中镉的赋存形态和生物有效性影响,结果表明：在碱性的镉污染土壤上,秸秆炭化后还田降低了玉米地上部生物量,但对玉米地上部镉含量和镉吸收量无显著影响;在酸性的模拟镉污染土壤上秸秆炭化后还田对玉米生长无影响,但还田含镉的油菜秸秆黑炭显著增加了玉米地上部镉含量和镉吸收量;还田不含镉的玉米秸秆黑炭对镉污染土壤中DTPA提取态镉含量没有明显影响,但还田含镉的油菜秸秆黑炭显著增加了镉污染土壤中DTPA提取态镉含量;施用含镉的油菜秸秆黑炭增加了镉污染土壤中水溶和交换态镉含量;施用玉米和油菜秸秆黑炭均显著降低了模拟镉污染土壤中水溶和交换态镉含量;增加了松有机结合态、碳酸盐结合态和紧有机结合态镉含量;模拟镉污染土壤施用玉米和油菜秸秆黑炭6个月后土壤中水溶和交换态镉仍然是土壤镉的主要赋存形态,水溶和交换态镉占土壤全镉的70%以上。综合以上结果可知,秸秆黑炭不能降低污染土壤中镉的生物有效性和植物对土壤镉的吸收量。     

Influence of Urea and Ammonium Sulfate on Soil Acidity Indices in Lowland Rice Production

Urea and ammonium sulfate are principal nitrogen (N) sources for crop production. Two field experiments were conducted during three consecutive years to evaluate influence of urea and ammonium sulfate application on grain yield, soil pH, calcium (Ca) saturation, magnesium (Mg) saturation, base saturation, aluminum (Al) saturation, and acidity (H + Al) saturation in lowland rice production. Grain yield was significantly influenced by urea as well as ammonium sulfate fertilization. Soil pH linearly decreased with the application of N by ammonium sulfate and urea fertilizers. However, the magnitude of the pH decrease was greater by ammonium sulfate than by urea. The Ca and Mg saturations were decreased at the greater N rates compared to low rates of N by both the fertilizer sources. The Al and acidity saturation increased with increasing N rates by both the fertilizer sources. However, these acidity indices were increased more with the application of ammonium sulfate compared with urea. Rice grain yield had negative associations with pH, Ca saturation, Mg saturation, and base saturation and positive associations with Al and acidity saturation. This indicates that rice plant is tolerant to soil acidity.     

Der Einfluß variierter Düngergaben von Stickstoff,Kupfer und Magnesium auf den Ertrag von Hafer

The Influence of varying Amounts of Nitrogen, Copper and Magnesium on the Yield of Oat 1. In pot experiments with oat high amounts of copper (500 mg) copper sulfate/pot, comparable to 50 kg (Cu/ha) together with a high nitrogen supply as calcium nitrate led to a remarkable increase in yield of grain in comparison to a normal copper fertilization (50 mg copper sulfate/pot, comparable to 5 kg Cu/ha). When using high amounts of ammonium sulfate the observed effect of high amounts of copper was only small. 2. According to the results and to the copper content and copper uptake of the plant it was concluded, that nitrogen fertilization given as ammonium sulfate increased the availability of soil copper and/or fertilizer copper presumably by affecting the soil reaction. Nitrogen fertilization given as calcium nitrate therefore needs a higher copper level in the root medium either from soil or fertilizers in order to obtain the maximum yield. 3. It was assumed that the form of nitrogen fertilizers was responsible for the different availability of copper in these experiments, as the amount of available copper in the soil increased with the lowering of soil pH due to ammonium sulfate addition. 4. The high copper supply to the soil remarkably reduced the harmful effect of high amounts of nitrogen given as calcium nitrate but not as ammonium sulfate. 5. The nitrogen fertilization with calcium nitrate, especially in combination with a high copper supply, resulted in the reducing effect of a magnesium deficiency. 6. The harmful effect of high amounts of nitrogen, especially in the ammonium sulfate form, upon yield was reduced by an optimal magnesium supply. 7. The results presented suggest that for evaluating the copper status of the soil and for estimating the demands of copper fertilization, soil reaction and its change by the form of nitrogen fertilizers should more be taken in consideration.     

外加氮源在Cd超标菜地上的应用效果

探讨外加氮源对Cd超标菜地不同叶菜吸收Cd及土壤Cd有效性的影响,以明确施氮对土壤Cd的影响效应,并试图对不同氮源的应用效果进行综合评价,为合理利用氮肥来降低叶菜Cd含量提供参考。在Cd含量为0.628 mg·kg?1的Cd超标菜地上,试验研究了氮用量水平为150 kg·hm?2时,4种氮肥(尿素、硝酸钙、硝酸铵、碳酸氢铵)对矮脚葵扇黑叶白菜(Brassica chinensis L.)和白梗尖叶苋菜(Amaranthus mangostanus L.)Cd含量、品质及土壤Cd有效性的效应。结果表明,田间条件下,与不施氮处理相比,4种氮肥均不同程度地增加了Cd超标菜地上2种叶菜产量,降低了其地上部和根系Cd含量。4种氮肥中,尿素对白梗尖叶苋菜的增产效果最好,增产幅度达47.5%;碳酸氢铵对葵扇黑叶白菜的增产效果最好,增幅达59.7%;硝酸钙降低2种叶菜地上部和根系Cd含量的效果均优于其他氮肥,该处理的白梗尖叶苋菜地上部和根系Cd含量分别比对照降低41.6%和24.1%,葵扇黑叶白菜降低32.2%和25.9%。4种氮源对2种叶菜地上部Cd吸收总量、NO3?-N、NO2?-N、维生素C及可溶性糖含量等的影响各异,对土壤p H和DTPA-Cd含量影响也不同。其中,硝酸铵处理的土壤p H分别比对照降低0.12和0.25个单位,而土壤DTPA-Cd含量则显著增加15.3%和14.6%;碳酸氢铵处理则呈相反变化趋势。综合评价结果显示,4种氮肥的综合加权平均值均高于对照处理,以硝酸钙相对最高,表明硝酸钙在Cd超标菜地上的综合应用效果相对最好。因此,在Cd超标土壤上,硝酸钙可作为优选氮源使用。     

氮肥对镉在土壤-芥菜系统中迁移转化的影响

以芥菜为研究对象, 采用盆栽试验, 探讨了不同用量的5种氮肥对污染农田土壤中镉(Cd)在土壤–根系–地上部迁移累积的影响。结果表明: 5种氮肥均促进了芥菜根系对Cd的吸收, 且根系Cd含量随施氮量的增加而增加; 但根系吸收转运Cd的能力随氮肥施用量的增加呈先降后增的变化趋势。在≤200 mg(N)·kg^-1(土)的施氮水平下, CO(NH₂)₂和Ca(NO₃)₂处理能显著降低芥菜地上部Cd含量, 降低幅度分别为13%~29%和24%~30%。在施氮量相同的条件下, NH₄Cl和(NH₄)₂SO₄显著降低了土壤pH, 增加了土壤DTPA-Cd含量, 促进了芥菜对Cd的吸收。本试验条件下, 200 mg(N)·kg^-1(土)的CO(NH₂)₂在增加芥菜产量和降低芥菜地上部Cd含量等方面优于其他氮肥处理。     

水肥一体化配合硝化/脲酶抑制剂实现油菜减氮增效研究

【目的】研究水肥一体化方式下减氮施肥并添加硝化和脲酶抑制剂对油菜生长及土壤硝态氮和铵态氮含量的影响,旨在筛选出配合硝化/脲酶抑制剂施用的最适减氮量,为减少氮素损失、提高蔬菜生产中氮素利用率和降低蔬菜硝酸盐含量提供理论依据。 【方法】采用盆栽试验,利用负压灌溉水肥一体化系统 [(–5 ± 1) kPa],设不施氮肥 (T1)、尿素 150 kg/hm2 (T2)、尿素 150 kg/hm2 + 10%DCD (双氰胺) + 1%HQ (氢醌)(T3)、尿素 127.5 kg/hm2 + 10%DCD + 1%HQ (T4)、尿素 105 kg/hm2 + 10%DCD + 1%HQ (T5) 共 5 个处理。监测了油菜生长期间供水量、土壤含水量、油菜生长指标及土壤硝态氮与铵态氮含量的变化,分析调查了收获后油菜的产量、品质指标和养分含量。 【结果】在油菜生长期间,负压灌溉各处理的总出水量非常接近 (12174～13869 mL)。当施肥量相同时,与不添加抑制剂处理 (T2) 相比,施用硝化和脲酶抑制剂 (T3) 能够有效抑制土壤中铵态氮向硝态氮的转化,提高叶长、叶宽和叶绿素含量,显著提高油菜产量 25.2%,提高氮肥利用率 85.2%,硝酸盐含量显著降低 51.9%。与不添加抑制剂处理 (T2) 相比,减氮 15%～30% 同时添加硝化和脲酶抑制剂对油菜产量、品质、养分吸收也均有不同程度的促进效果,并能够抑制硝化作用,减少土壤中硝态氮累积,减氮 30% 并添加硝化和脲酶抑制剂的处理 (T5) 能将油菜产量提高 15.9%,氮、磷、钾含量分别提高 8.4%、21.5% 和 27.8%,氮肥利用率提高 1.26 倍,油菜体内硝酸盐含量降低 66.6%。 【结论】适当减氮并添加硝化和脲酶抑制剂对油菜产量和养分吸收均有明显的促进效果,而且能减少油菜硝酸盐含量和土壤中硝态氮累积。在本试验负压水肥一体化条件下,减氮 30% 并添加硝化和脲酶抑制剂,即尿素 105 kg/hm2 + 10%DCD + 1%HQ 不仅效果最佳,还降低了因氮肥投入高而造成硝酸盐累积的风险。     

Ammonia volatilization from nitrogen fertilizers with and without gypsum

Abstract. Ammonia volatilization with and without gypsum incorporation was measured in Gujranwala soil (Udic Haplustalf) in an incubation study using different nitrogen fertilizers e.g. urea, ammonium sulphate (AS), calcium ammonium nitrate (CAN), and urea nitrophos (UNP). Nitrogen from different fertilizers was applied at the rate of 200 mg N kg⁻¹ to two sets of soils in plastic bags (1.0 kg soil) and plastic jars (0.5 kg soil). Soil moisture was maintained at field capacity. Application of urea increased soil pH to 9, three hours after its addition. Ammonium sulphate and calcium ammonium nitrate had little effect on soil pH. Ammonium volatilization losses from fertilizers were related to the increase in soil pH caused by the fertilizers. Consequently maximum losses were recorded due to application of urea. Losses through ammonia volatilization were significantly lower with AS, CAN and UNP in descending order. Gypsum incorporation significantly reduced the losses. Therefore, application of gypsum to soil before urea may substantially improve N use efficiency for crop production by reducing N losses.     

Studies on mineralization and immobilization of nitrogen in soil

Mineralization and immobilization processes were studied in a soil treated with ammonium sulphate, calcium ammonium nitrate, urea, urea ammonium phosphate or suphala along with unhumified dung. The conversion of fertilizer nitrogen into non-KCI extractable fractions occurred within two weeks and was relatively rapid in the samples treated with urea and urea ammonium phosphate. The mineral nitrogen content during incubation studies was highest in calcium ammonium nitrate treated soils. Amino acid nitrogen appeared to be the main fraction involved in the immobilization and mineralization of nitrogen in soil. Dung behaved as an efficient nitrification inhibitor and slowed the release of nitrogen from fertilizers.     

根际施肥调控对油菜硝酸盐含量的影响研究

利用盆栽试验,测定了肥料周围不同距离处土壤中NH4+与NO3-增量的变化,验证不同施肥方式对小油菜产量与NO3-含量的影响。结果发现,通过肥料在土壤中的扩散作用,肥料氮对土壤NH4+与NO3-增量的影响范围主要是在距肥料4cm内,但集中施肥与酸性根际肥(Ph1.0～2.0)的显著差异则是在2cm内;后者的NH4+扩散与硝化作用都较前者弱。其中,在距肥料1cm处,集中施肥的土壤NH4+增量于施肥一周后达最大值,而酸性根际肥则在两周后,且两者NH4+增量差异显著;在2cm处,二者土壤NH4+增量达最大值的时间都较1cm处晚一周,且前者显著低于后者,而后者土壤的NO3-增量都低于前者。在盆栽试验中,酸性根际肥使小油菜的土壤NH4+含量显著提高,而NO3-含量却很低。与集中施肥比较,土壤NH4+含量提高13%,NO3-含量降低72%～89%,小油菜的硝酸盐累积量降低了28%,小油菜产量增加39%。     

Mineral fertilizers with iron influence spring rape,maize and soil properties

ABSTRACT

Because of low content of available iron (Fe) in soils and its poor mobility in plants, iron fertilization is necessary. Different forms of iron (mineral salts, chelates, nanomaterials) and fertilization strategies (soil and foliar application of solid or liquid fertilizers) are used. The effect of solid mineral fertilizers (A: a mixture of ammonium nitrate and dolomite; B: a mixture of ammonium nitrate and sulfate) enriched with iron sulfate was assessed during a three-year pot experiment. Iron addition did not change the yield of spring rape (first year) or maize (second and third year) significantly, and the effect on iron content in the plants was ambiguous. Fertilizer B with iron had the greatest yield-forming effect, increasing the yield of aboveground parts by 355–874%, and of roots by 211–692% in particular years. All fertilizers (especially containing sulfur) acidified the soil. After the experiment, pH of the soil fertilized with sulfur was 4.1, and of the unfertilized soil – 5.2. Iron addition increased the content of mobile and exchangeable iron in the soil by 12–110% and 2–58%, respectively, but not the content of the fraction bound to MnO_x. Combination of sulfur and iron fertilization has a potential to improve soil abundance and plant yield.