Evaluation of the Nitrification Inhibitor 3,4-Dimethylpyrazole Phosphate in Two Chilean Soils

ABSTRACT

Two Chilean soils were used to evaluate the performance of the nitrification inhibitor 3,4-dimetilpirazol phosphate (DMPP) added to ammonium-sulfate-nitrate (ASN) in comparison with traditional nitrogen (N) sources and different N-application forms. Two experiments were conducted: In the first, broccoli (Brassica oleracea var. italica) plants were cultivated in pots under greenhouse conditions, and received a N-fertilization equivalent to 150 Kg N ha^?1 as ASN+DMPP (one application), urea (two splits), and sodium-potassium nitrate (three splits). In the second, ryegrass (Lolium spp.) plants were grown in pots under shading conditions. In this case, ASN+DMPP and urea were applied at N rates equivalent to 150 and 300 Kg N ha^?1 in a single application. In the first experiment, ASN+DMPP increased dry-matter production, maintained a higher N content in the soil (at least until the middle of the growing period), and improved fertilizer N-use efficiency (FUE) in one soil. There were no significant differences in N-leaching losses. In the ryegrass experiment, ASN+DMPP increased dry-matter production and FUE, while N-leaching losses were reduced. Treatments with ASN+DMPP maintained higher N levels in soil throughout the growing period, and there were no significant differences in the available N fraction between the two N rates. The use of DMPP-containing fertilizers may be a good alternative for increasing FUE.     

Effect of a Nitrification Inhibitor (3,4-Dimethylpyrazole Phosphate) on Leaching Water Collected from Rose Plants Grown in Four Different Growing Media

A greenhouse experiment was conducted for 130 days to assess the effect of application of uncoated urea (UA) and 3,4-dimethylpyrazole phosphate–coated urea (UDMPP) on mineral nitrogen (N) content [ammonium (NH₄ ⁺)-N and nitrate (NO₃ ^?)-N] in leachates and growing media. Charlotte rose plants grafted on Natal Briar were cultivated in four different media [soil, 100% burnt rice husks (100BRH), a mixture of 65% burnt rice husks and 35% coconut fiber (65BRH), and 100% coconut fiber (100CF)] and fertigated with UA or UDMPP at rate of 170 mg N·L^?1. Results showed that fertilizer induced slight acidity in the leachate collected in all growing media. The use of DMPP diminished cumulative nitrate losses by ?65 and ?60%, in soil and coconut fiber leachates, respectively, as compared to the plots with UA. The UDMPP did not have any effect on nitrate losses in BRH media.     

运用同位素~(15)N研究冬小麦不同时期追施尿素的效果及氮肥的利用率

本文运用同位素15N,对冬小麦不同追肥时期的效果 ,氮肥的利用率 ,氮素在秸杆、籽粒中的分配、土壤残留、挥发损失进行了研究。结果表明 :拔节期追肥一次 ,再加上追施穗肥一次效果最好 ;前期追肥 ,秸杆对 N的利用率高 ,籽粒对 N的利用率低 ;后期追肥 ,籽粒对 N的利用率高 ,秸杆对 N的利用率低 ;前后期结合追肥比一次追肥土壤氮素残留量高 ,损失较少。     

不同施氮量配施硝化抑制剂对柴达木枸杞园15N肥料去向的影响

枸杞产业已成为青藏高原的优势产业,但存在氮肥利用率低、环境污染等问题。适当施用氮肥和硝化抑制剂是减少氮肥气态损失、提高氮肥利用率和降低温室气体排放的有效途径。为探讨枸杞栽培的适宜施肥方式,于2020年在柴达木盆地青海诺木洪农场,以11年生宁杞1号为试验材料开展田间试验,设置4个处理：N₂₆₇、N₁₃₃处理分别施用纯氮267、133 kg·hm^-2,N₂₆₇I_1.33、N₁₃₃I_0.67处理分别在N₂₆₇、N₁₃₃处理施氮量的基础上配施硝化抑制剂—2-氯-6(三氯甲基)-吡啶(nitrapyrin)1.33、0.67 kg·hm^-2,研究施氮量和2-氯-6(三氯甲基)-吡啶对施用的¹⁵N-尿素在枸杞-土壤系统去向的影响。结果表明,N₂₆₇I_1.33处理枸杞全株的干物质量、吸氮量和植株¹⁵     

稳定性同位素碳、氮在牛不同组织中的变化规律

稳定同位素分析是追溯食品来源的一种有效技术。本文主要探讨了在相同的饲养条件下,牛不同组织中碳、氮同位素组成的变化情况以及品种对其的影响。利用同位素比率质谱仪测定了不同部位脱脂牛肉、不同部位粗脂肪、牛尾毛、血液、肝脏及饲料中的δ13C值和δ15N值,并进行了统计分析。结果表明,品种因素不影响组织中的碳、氮同位素组成;肌肉不同部位、血液、肝脏、牛尾毛之间的δ13C值无显著差异,而肝脏中的δ15N值极显著地高于其它组织;不同部位粗脂肪间的δ13C值也无显著差异。结果说明稳定性同位素碳、氮在牛不同组织中的分馏效应是不一致的。     

不同施肥处理对连续三季作物氮肥利用率及其分配与去向的影响

采用室外盆栽试验系统研究了不同施肥处理对连续3个生长季作物生长状况、标记^15N利用率及其分配与去向的影响。结果表明,高量氮肥的施用能显著提高作物的生长和产量,而化肥配施玉米秸秆在第1生长季表现为抑制,第2、第3生长季则相反。作物体内来自标记氮肥的含量和比例随生长季的增加显著下降,高量氮肥和玉米秸秆的施用能显著提高其含量和比例（P〈0.05）。标记氮肥在土壤中的残留率随作物生长季的增加而降低,而标记氮肥的累积作物利用率和总损失率随着生长季的增加而增加,经过连续3季作物的吸收利用,标记氮肥在土壤中的残留率、累积作物利用率和总损失率分别平均为15．82％、61．11％和23．07％。标记氮肥的作物利用率和损失率主要发生在第1生长季内,高量氮肥的施用降低了标记肥料氮在土壤中的残留率,增加了氮素损失率;与单施化肥处理相比,化肥配施玉米秸秆能明显增加标记肥料氮在土壤和作物中的回收率,降低氮素损失率,提高比例为21．74％,从而说明在施肥当季,通过施入高C/N比有机物料玉米秸秆合理调节土壤中C源和N素营养的施用比例,可以达到增加氮肥在土壤中的残留率,提高氮肥利用率的目的。     

15N示踪法研究不同灌水处理对小麦氮素吸收分配及利用效率的影响

通过田间试验,采用15N示踪法,设置全生育期不灌水（W0）、冬水+拔节水（W1）、冬水+拔节水+开花水（W2） 3个灌水处理,每次灌水60 mm,每个灌水处理下,设置15N尿素作底肥+普通尿素作追肥、普通尿素作底肥+15N尿素作追肥2个15N示踪处理的微区,研究不同灌水处理对小麦氮素吸收分配及利用效率的影响。结果表明,成熟期地上部植株氮素积累量及来源于土壤的氮素的积累量均为:W2＞W1＞W0;肥料氮的积累量为W0、W1＞W2。W1处理基肥氮积累量及比例均显著低于W0处理,追肥氮的积累量及比例均显著高于W0处理;W2处理基肥氮和追肥氮的积累量均显著低于W0处理。成熟期肥料氮在植株各器官的分配量为:子粒＞茎秆+叶鞘＞叶＞穗轴+颖壳;各处理营养器官中基肥氮的比例高于追肥氮,子粒中追肥氮的积累量及比例高于基肥氮。子粒中分配的肥料氮量为W0、W1＞W2。W1处理子粒产量最高,植株中肥料氮的积累量及利用率均高于W2处理。说明灌溉冬水+拔节水促进了小麦对追肥氮和土壤氮素的吸收积累,提高了肥料氮的积累量和利用率;在此基础上增灌开花水,地上部积累的追肥氮量及其向子粒中的分配比例均显著降低,这是花后供水多导致产量和氮肥利用效率显著降低的生理原因。     

黄壤上烤烟氮素积累、分配及利用的研究

田间条件下,利用同位素15N示踪技术于黄壤有机质含量分别为19.2和40.7 g/kg和当地推荐最佳氮肥用量基础上,设15N用量分别为105和82.5 kg/hm2的情况下,研究了两个试验点烤烟15N积累、吸收比例、氮素利用率及15N在各器官分配。结果表明,在二种有机质含量的黄壤上,烤烟15N吸收规律相似,于烤烟移栽后3~5周内,烟株吸收15N较少,5周后15N积累量明显增加,到移栽后13周达到高峰,肥料15N吸收时间拖后;二种土壤上,肥料15N在整个生育期内积累量分别为28.41和26.55 kg/hm2。烟株于移栽后3~5周来自肥料15N占吸收总氮的比例为53.84%～71.33%,氮（15N）肥利用率为1.11%～7.34%;到烟叶采收结束（移栽后17周）时,烟株来自肥料15N占吸收总氮的比例为28.69%～29.75%,氮（15N）肥利用率为27.06%～32.18%。各个部位烟叶采收结束时,二种土壤上,肥料15N在上部、中部、下部烟叶及茎和花积累分别占吸收肥料总15N的35.08%~35.26%、25.87%~26.19%、17.92%~18.25%和22.73%~24.49%,肥料15N主要集中在中、上部烟叶。可见,肥料氮吸收时期拖后,土壤后期供氮能力强和中上部烟叶肥料氮比例较高是黄壤烟区烤烟氮素营养存在的主要问题。     

Isotope 15N enrichment of soil-ammonium N as a reference to estimate N2 fixation by stem and root-inoculated S. rostrata

Summary A pot experiment in the greenhouse was conducted to compare the contribution of N derived from the atmosphere or from biological N₂ fixation by Sesbania rostrata inoculated with Azorhizobium caulinodans, applied either to roots or to roots and stems (single or multiple stem inoculation). Two subsequent crops were grown for 50 days under flooded conditions. N derived from air was estimated by ¹⁵N dilution using ¹⁵N enrichment of soil NH _inf4 ^sup+ -N and of Echinochloa crusgalli as the non-N₂-fixing reference datum and compared with estimates obtained by the N-difference method. The first crop was grown to stabilize the ¹⁵N into the soil organic N fraction. The ¹⁵N enrichment of soil NH _inf4 ^sup+ -N in the second crop declined slowly. The extractability ratio (¹⁵N enrichment of extractable soil N to ¹⁵N enrichment of total soil N) decreased from 4.8 to 4.1 50 days after planting. The enrichment of soil NH _inf4 ^sup+ -N was comparable to that of E. crus-galli, resulting in similar estimates of N derived from air when either soil NH _inf4 ^sup+ -N or enrichment of E. crus-galli was used as a non-fixing reference. The N-difference method did not always provide reliable estimates of N derived from air; percentages ranged from 75 to more than 80 by 50 days after planting in both crops and did not differ among treatments. The study demonstrates the potential of using ¹⁵N enrichment of soil NH _inf4 ^sup+ -N as a non-N₂-fixing reference for reliable BNF estimates of crops in lowland puddled soil.