Phosphorus efficiency in long-term (15 years) wheat–maize cropping systems with various soil and climate conditions

Long-term (over 15 years) winter wheat (Triticum aestivum L.)–maize (Zea mays L.) crop rotation experiments were conducted to investigate phosphorus (P) fertilizer utilization efficiency, including the physiological efficiency, recovery efficiency and the mass (the input–output) balance, at five sites across different soil types and climate zones in China. The five treatments used were control, N, NP, NK and NPK, representing various combinations of N, P and K fertilizer applications. Phosphorus fertilization increased average crop yield over 15 years and the increases were greater with wheat (206%) than maize (85%) across all five sites. The wheat yield also significantly increased over time for the NPK treatments at two sites (Xinjiang and Shanxi), but decreased at one site (Hunan). The P content in wheat was less than 3.00 g kg⁻¹ (and 2.10 g kg⁻¹ for maize) for the N and NK treatments with higher values for the Control, NP and NPK treatments. To produce 1 t of grain, crops require 4.2 kg P for wheat and 3.1 kg P for maize. The P physiological use efficiency was 214 kg grain kg⁻¹ P for wheat and 240 kg grain kg⁻¹ P for maize with over 62% of the P from P fertilizer. Applying P fertilizer at 60–80 kg P ha⁻¹ year⁻¹ could maintain 3–4 t ha⁻¹ yields for wheat and 5–6 t ha⁻¹ yields for maize for the five study sites across China. The P recovery efficiency and fertilizer use efficiency averaged 47% and 29%, respectively. For every 100 kg P ha⁻¹ year⁻¹ P surplus (amount of fertilizer applied in excess of crop removal), Olsen-P in soil was increased by 3.4 mg P kg⁻¹. Our study suggests that in order to achieve higher crop yields, the long-term P input–output balance, soil P supplying capacity and yield targets should be considered when making P fertilizer recommendations and developing strategies for intensively managed wheat–maize cropping systems.     

不同肥料滴灌配施夏玉米产量与氮磷钾吸收利用特性

以郑单958为材料,在滴灌施肥条件下设不施氮(N0)、不施磷(P0)、不施钾(K0)和氮磷钾均施(NPK)4个处理,以传统灌溉施肥方式(施用量同NPK处理)为对照,研究滴灌水肥一体不同肥料配施夏玉米产量与氮磷钾吸收、分配及利用特性。结果表明,滴灌条件下,相较于磷钾肥,玉米对氮肥更敏感。N0处理的产量、干物质积累量、整株氮磷吸收量均显著降低,其叶片钾含量、茎鞘磷含量极显著增加,导致叶片钾积累量、茎鞘磷积累量显著增加。P0和K0处理玉米产量、干物质积累量、植株氮素吸收量均与NPK处理无显著差异,分别导致磷素和钾素吸收量显著降低。不施磷钾肥处理氮素从秸秆向子粒的转运受到限制,子粒含氮量下降,氮素收获指数显著降低。滴灌条件下,氮磷钾肥平衡施用玉米养分吸收均衡、分配合理,物质生产和产量显著高于传统灌溉施肥方式。     

不同施肥条件下冬小麦氮素吸收、转运及累积的研究

为给陕西关中地区冬小麦合理施用氮肥提供理论基础,以小偃22为材料,通过田间试验研究了不同施肥条件下冬小麦产量、氮素吸收、转运和累积特点.结果表明,氮磷钾和有机肥配合施用可明显提高小麦籽粒产量,其中在基施有机氮150 kg·hm-2的基础上,施氮量为150～225 kg·hm-2时小麦籽粒产量接近或达到9 000 kg·hm-2的超高产水平,显著高于农民习惯施肥处理(基施纯氮300 kg·hm-2和P2O5 75 kg·hm-2);在不施有机肥、施氮量为270～300 kg·hm-2时,小麦籽粒产量与农民习惯施肥处理差异不明显,说明有机肥具有明显的增产作用.施肥处理时小麦氮素累积有显著影响,氮磷钾配施可显著提高小麦氮素累积量,有机肥和化肥配合施用氮素累积量最高,达到249.3～283.0 kg·hm-2.与农民习惯施肥处理相比,氮磷钾配施条件下小麦生育中期和后期氮素累积量增加,开花后营养器官氮素转运量也随着增加,但施肥处理间氮素转运效率差异不明显.综合来看,陕西关中地区冬小麦在氮磷钾和有机肥配合施用的情况下,氮肥用量应控制在150～225 kg·hm-2.     

氮磷钾配施对砂姜黑土花生产量的影响

在砂姜黑土上，施肥可显著促进花生生长发育，提高荚果和籽仁产量；氮磷钾酸施效果优于氮钾配施，氮钾配施又优于氮磷配施。氮磷钾配施较氮钾配施荚果增产15.7%、24.8%，籽仁增产13.6%、26.5%；较不施肥荚果增产39.7%，籽仁增产43.2%。实行氮磷钾平衡施肥是提高砂姜黑土花生产量的有效措施。     

Nitrogen efficiency in long-term wheat–maize cropping systems under diverse field sites in China

Efficiency of fertilizer N is becoming increasingly important in modern agricultural production owing to increasing food requirement and growing concern about environments. However, there is almost no study regarding its long-term efficiency in wheat and maize cropping systems. Long-term (15 years) experiments involving wheat (Triticum aestivum L.) and maize (Zea mays L.) rotations at five field sites with various soil and climate characteristics in China were used to determine the nitrogen (N) efficiency, including the physiological efficiency, recovery efficiency and N mass balance of soil–plant systems in response to different fertilization treatments. The present study consisted of nine treatments: unfertilized, N, phosphorus, potassium, straw and manure or their combinations. The contribution of N fertilizers to wheat yield was higher than to maize and suggested that wheat could be given priority over maize when determining N application rates. Uptake of 1 kg N produced 35.6 kg of wheat grain and 39.5 kg of maize grain. The deficit of N in soils without applied N ranged from 40 to 103 kg N ha⁻¹ year⁻¹, while N surpluses in soils with applied N fertilizers ranged from 35 to 350 kg N ha⁻¹ year⁻¹. The apparent accumulated N recovery efficiency (NRE_ac) varied widely from 4% to 90%: unbalanced fertilization and other soil limiting factors (such as aluminium toxicity) were associated with low NRE_ac. In the treatments of combination of N, phosphorus and potassium with normal application rates, the average of NRE_ac in four out of five sites reached 80%, which suggested that best management of N fertilizers could recover most of N fertilizers applied to soils. The results will be helpful to understand the long-term fate of N fertilizers and to optimize the N fertilization for agricultural practices and environment protection.     

施肥对甜菜氮代谢的效应研究

为明确不同品种在氮吸收、积累、氮效率、氮肥利用率等方面的差异及施肥的效应,选用HI0466及SR411两个品种,在黑龙江大学呼兰校区进行田间试验。结果表明:①施肥对甜菜的氮吸收和积累影响显著,其中以NPK组合最高,NP或NK组合次之,PK组合增加最低;②不同品种氮吸收能力不同,品种HI0466的氮吸收能力高于SR411,并主要体现在地上部植株含氮量和吸氮总量两个性状指标上;③品种SR411的氮肥利用率、氮肥生理效率、氮肥农学效率均显著高于品种HI0466;④施肥对不同品种甜菜的氮肥生理效率、氮肥农学效率影响各异,三要素配合施用时两个品种的这两个效率均为最高,缺P对HI0466的农学效率和SR411的生理效率的负效应高于缺K,而缺K对SR411的农学效率和HI0466的生理效率的负效应高于缺P。     

黑土区长期施肥对大豆光合产物分配的影响

在东北黑土区中心-中同科学院海伦实验站进行盆栽试验,研究不同施肥处理对大豆光合产物分配的影响.设5个肥料处理,分别为无肥(CK)、氮磷(NP)、氮钾(NK),氮磷钾(NPK)和化肥有机肥配施(NPK+OM),同时进行相应肥料的无作物处理.结果发现:光合产物的分配趋势表现出分配到地上部的比例逐渐增加,由35%增加到66%,同时地下部所占有的比例相应减少,南65%降低到34%.其中分配到根中的光合产物有4%～20%通过根系呼吸而消耗.碳同化产物的分配受施肥的影响(P＜0.05).随着大厦的生长,土壤呼吸速率逐渐增加,在培养后的第77天,CK、NP、NK、NPK和NPKOM处理土壤呼吸速率达到最大值,分别为113、164、143、222、274 mg C·cm-2·h-1,然后逐渐降低,到生育末期达到最小值.不同施肥处理土壤呼吸速率存在差异,大小顺序为NPK+OM＞NPK＞NP＞NK＞CK,在整个生长季的变化范围分别为29～302,25～238,25～185,24～160 and 20～129 mg C·m-2·h-1.     

Effect of tillage and nutrient management on wheat productivity and quality in Haryana, India

This article reports on field experiments with 4 different rotations that are commonly used throughout Haryana in NW India (rice-wheat, cotton-wheat, pearl millet-wheat, cluster bean-wheat), where we assess wheat yield and chapatti quality measures with different crop establishment methods and input of micronutrients. In a series of experiments conducted on farmers’ fields in 2007-2008 and 2008-2009 winter seasons, the addition of micronutrients and sulphur to wheat crops was used alongside the use of a common farmer practice, the use of farmyard manure (FM) and best practice inputs of N-fertilizer (150 kg N ha⁻¹), P-fertilizer (26 kg P ha⁻¹) and K-fertilizer (33 kg K ha⁻¹). The application of FM with the recommended NPK treatment produced 9-13% more grain yield in the rice-wheat rotation when compared with the recommended NPK only treatment. Given that the farm sites used here had low levels of soil P, this may suggest that the recommended rate of 26 kg P ha⁻¹ for the rice-wheat rotation is too low. The addition of FM did not improve any grain quality outcomes at any of the sites. There were no yield responses with S application with any of the rotations but the S input resulted in more wheat protein from all sites (average 8%). The addition of S also gave similar increases in grain hardness and the chapatti score. The inclusion of micronutrients (boron, copper, iron, zinc and manganese) with the recommended NPK treatment did not increase the grain yield at any of the sites when compared with the recommended NPK treatment, and sometimes, but not consistently, gave small responses with protein, grain hardness and chapatti score. In concurrent experiments wheat growth and chapatti quality were compared in zero till and conventionally sown systems, and with and without S fertilizer amendment. Here too there were no grain yield responses to S, and the protein, grain hardness and chapatti score were increased with S addition. Grain yields with zero till and conventional wheat were similar in the rice-wheat system and zero till sowing resulted in small increases in yield at all of the non-rice sites. The grain from the zero till treatments had higher protein (1-3%), grain hardness (3-10%) and chapatti score from all 4 rotations. Zero till has substantial adoption in the rice-wheat districts of Haryana but little farmer awareness and adoption in the areas where the other rotations are used. The data given here show that with zero tillage and an integrated practice of nutrient management farmers in Haryana can maintain grain yields of wheat whilst improving quality outcomes.     

Dryland maize yields and water use efficiency in response to tillage/crop stubble and nutrient management practices in China

Rainfed crop production in northern China is constrained by low and variable rainfall. This study explored the effects of tillage/crop residue and nutrient management practices on maize (Zea mays L.) yield, water use efficiency (WUE), and N agronomic use efficiency (NAE) at Shouyang Dryland Farming Experimental Station in northern China during 2003–2008. The experiment was set-up using a split-plot design with 3 tillage/crop residue methods as main treatments: conventional, reduced (till with crop residue incorporated in fall but no-till in spring), and no-till (with crop residue mulching in fall). Sub-treatments were 3 NP fertilizer rates: 105–46, 179–78 and 210–92 kg N and P ha⁻¹. Maize grain yields were greatly influenced by the growing season rainfall and soil water contents at sowing. Mean grain yields over the 6-year period in response to tillage/crop residue treatments were 5604, 5347 and 5185 kg ha⁻¹, under reduced, no-till and conventional tillage, respectively. Grain yields under no-till, were generally higher (+19%) in dry years but lower (−7%) in wet years. Mean WUE was 13.7, 13.6 and 12.6 kg ha⁻¹ mm⁻¹ under reduced, no-till, and conventional tillage, respectively. The no-till treatment had 8–12% more water in the soil profiles than the conventional and reduced tillage treatments at sowing and harvest time. Grain yields, WUE and NAE were highest with the lowest NP fertilizer application rates (at 105 kg N and 46 kg P ha⁻¹) under reduced tillage, while yields and WUE tended to be higher with additional NP fertilizer rates under conventional tillage, however, there was no significant yield increase above the optimum fertilizer rate. In conclusion, maize grain yields, WUE and NAE were highest under reduced tillage at modest NP fertilizer application rates of 105 kg N and 46 kg P ha⁻¹. No-till increased soil water storage by 8–12% and improved WUE compared to conventional tillage, thus showing potentials for drought mitigation and economic use of fertilizers in drought-prone rainfed conditions in northern China.     

长期隔年施磷对陇东旱塬作物产量和土壤肥力的影响

为探讨不同施肥方式对旱地土壤的培肥作用及增产效果,以1979-2019年在甘肃省陇东旱塬黑垆上土进行的长期定位施肥试验为基础,研究了不施肥料(CK)、单施氮肥(N)、氮磷肥配施(NP)、秸秆还田+氮磷肥配施(磷肥为隔年施用,施磷年份该处理记为SNP,不施磷年份记为SN)4种措施对作物产量、产量稳定性和可持续性以及土壤综合肥力的影响。结果表明,长期隔年施磷(SN)的春玉米和冬小麦产量分别较CK增加151.4%和159.2%,较长期施磷处理(SNP)增加8.6%和6.9%;SN的春玉米产量稳定性和可持续性均低于N和NP处理,而冬小麦产量稳定性和可持续性均优于N和NP处理;SN处理显著提高了耕层土壤综合肥力(IFI),其耕层土壤IFI值分别较CK、N和NP处理高25.5%、21.3%和6.1%,年际间变异强度高于CK和N处理。说明,在陇东旱塬黑垆土春玉米-冬小麦轮作体系下,采用秸秆还田+氮磷配施隔年施磷技术,既在减少50%化学磷肥投入的情况下仍能保证作物产量稳定和持续,并能有效提高耕层土壤综合肥力。     

Using stress tolerance indicator (STI) to select high grain yield iron-deficiency tolerant wheat genotypes in calcareous soils

Despite large variation among crop genotypes in response to Fe fertilization, there is no reliable indicator for identifying Fe-deficiency tolerant wheat genotypes with high grain yield. The aim of this investigation was to compare the grain yield response of 20 spring and 30 winter bread wheat genotypes to Fe fertilization under field conditions and to select high grain yield Fe-deficiency tolerant genotypes using a stress tolerance indicator (STI). Two individual trials, each one consisting two field plot experiments, were conducted during 2006–2007 and 2007–2008 growing seasons. Spring wheat genotypes (Trial l) and winter wheat genotypes (Trial 2) were planted at two different locations. Two Fe rates (0 and 20 kg Fe ha⁻¹ as Fe-EDTA) were applied. Spring and winter wheat genotypes differed significantly (P < 0.01) in the grain yield both with and without added Fe treatments. Application of Fe fertilizer increased grain yield of spring wheat genotypes by an average of 211 and 551 kg ha⁻¹ in Karaj and Isfahan locations, respectively. By Fe application, the mean grain yield of winter wheat genotypes increased 532 and 798 kg ha⁻¹ in Karaj and Isfahan sites, respectively. Iron efficiency (Fe-EF) significantly differed among wheat genotypes and ranged from 65% to 113% for spring wheat and from 69% to 125% for winter wheat genotypes. No significant correlation was found between Fe-EF and grain yield of spring wheat genotypes under Fe deficient conditions. For winter wheat genotypes grown in Mashhad, Fe-efficiency was not significantly correlated with the grain yield produced without added Fe treatment. The STI was significantly (P < 0.01) varied among spring and winter wheat genotypes. The interaction between location and genotype had no significant effect on the STI. According to these results, the STI should be considered as an effective criterion for screening programs, if a high potential grain yield together with more stable response to Fe fertilization in different environments is desired.     

冬小麦碳氮积累、转运和籽粒产量对小花发育期追氮的响应

为给冬小麦高产优质栽培过程中氮肥的合理调控提供参考依据,通过河南郑州和兰考两点大田试验,分别在总施氮量240和180 kg·hm^-2下,以全部基施为对照,进行基施和追施各50%施氮处理［追肥时期分别在返青期(二棱末期)、返青后10 d(护颖原基分化期)、20 d(雌雄蕊原基分化期)和30 d(雌蕊凹期)］,探讨了小花发育期施氮对两种穗型冬小麦碳、氮积累和转运及产量构成的影响。结果表明,在小花发育期追施氮肥均有利于花前碳、氮的贮藏积累和转运,且兰考矮早8品种贮藏碳、氮转运对籽粒的贡献率分别高于对照处理4.49和3.98个百分点,而豫麦49198品种分别高于对照处理1.68和0.47个百分点;两个品种花前贮藏氮素转运对籽粒的贡献率分别高于碳素42.97和38.47个百分点。在本试验条件下,在小花雌雄蕊原基分化期追施氮肥增加了兰考矮早8的千粒重和豫麦49198的穗粒数,且追肥处理的穗粒数、千粒重和籽粒产量显著高于其他处理,氮素积累和转运的增加也显著提高了籽粒蛋白质含量和产量。根据本研究结果,在总施氮量180~240 kg·hm^-2下,采取基施和小花雌雄蕊原基分化期追施氮肥各50%,提高了籽粒产量和蛋白质产量。     

长期施肥对氮素利用以及土壤剖面氮素分布、积累的影响

依托28年长期定位试验，采集不同施肥处理土壤剖面样品，测定土壤硝态氮含量，结合产量计算氮素利用效率。结果表明，长期施肥显著增加玉米子粒产量、地上部总吸氮量及氮收获指数。化肥+有机肥(NPKM)处理产量最高，较单施化肥(NPK)处理提高8.7%。各处理硝态氮含量随着土层的加深均呈先降低后升高的趋势，硝态氮主要积累在0～100 cm土体，NPK、NPKM处理硝态氮积累量占比高于55%。因此，有机肥替代部分化肥可显著提高子粒产量，增加氮素利用效率，减少氮素淋溶。     

长期定位施用化肥对作物氮素吸收利用的影响

基于连续进行33年的长期定位试验,利用15 N示踪,研究长期施用化肥对冬小麦-夏玉米轮作中氮吸收利用的影响。结果表明,长期氮磷肥配施氮素利用率最高,为55.63%,与对照相比较提高了13.2%;其次为氮磷钾肥配施,氮素利用率为55.21%;氮磷钾肥配施处理氮素损失率最低,为8.71%。长期单施氮肥和氮钾肥配施的处理氮素利用率最低,分别为36.21%、34.53%,损失率高达38.63%、38.31%。     

氮磷钾运筹对不同小麦品种产量和品质的调节效应

为给小麦优质高产栽培提供理论依据,以强筋小麦品种济麦20和中筋小麦品种中麦175为试验材料,采用二因素随机区组设计,研究了氮磷钾运筹对小麦植株和产量性状、蛋白质和面筋含量、面团品质和烘焙品质的影响。结果表明,单施氮或氮磷、氮钾、氮磷钾配合施用,比单施磷、单施钾、磷钾配施以及不施肥处理显著增产,并改善了植株性状。施肥处理对籽粒蛋白质含量、面团品质和烘焙品质影响显著。籽粒产量性状和不同品质指标对施肥处理的反应有别,如施肥处理对产量、面团形成时间、稳定时间、拉伸面积影响较大,对容重、吸水率影响较小。不同品种的产量及品质指标对施肥处理的反应亦有差别,如中麦175的籽粒产量、面团拉伸阻力、拉伸比值、最大拉伸阻力、最大拉伸比值、面包体积和面包评分对施肥处理的反应敏感,其变异系数大于济麦20,而济麦20的面团形成时间、稳定时间对施肥处理的反应敏感,其变异系数大于中麦175。施氮对改善籽粒产量及主要品质性状的效果优于单施磷或单施钾处理。     

肥料无机有机配施对稻茬小麦产量与肥料利用率的影响

为了解无机肥与有机肥配施对稻茬小麦产量与肥料利用率的影响,于2016-2017小麦生长季,在湖北省襄阳市通过田间试验,设置不施肥（CK）、传统测土配方施肥（T1）、90%的传统测土配方施肥量+有机肥（T2）和80%的传统测土配方施肥量+有机肥（T3）4个处理,探讨不同施肥模式下小麦产量、分蘖动态、肥料利用效率和经济效益的差异。结果表明,施肥处理的籽粒产量、穗数和穗粒数均显著高于CK,千粒重较高。T2处理的籽粒产量、穗数、穗粒数和千粒重均高于T1和T3处理。施肥处理间群体密度、有效分蘖数和分蘖成穗率均无显著差异。与CK相比,T1、T2和T3处理的有效分蘖数分别提高51.6%、55.9%和53.8%,分蘖成穗率分别降低11.4%、8.8%和14.7%。T3处理的化肥农学利用效率和偏生产力以及N、P、K肥偏生产力均显著高于T2处理,T1处理最低。T1处理的小麦产投比和净收益均高于其他处理,分别为3.9和5 464.5元·hm^-2。综合来看,在本试验条件下,T2处理是相对高产高效的处理。     

Plant and soil responses to nitrogen and phosphorus fertilization of bromegrass‐dominated haylands in Saskatchewan,Canada

Field experiments were conducted at three different sites in Saskatchewan, Canada (Colonsay, Vanscoy and Rosthern) over two years (2005 and 2006) to determine the effects of dribble‐banded and coulter‐injected liquid fertilizer applied in the spring of 2005 at 56, 112 and 224 kg N ha^?1 with and without P at 28 kg P₂O₅ ha^?1. The three sites were unfertilized, 7‐ to 8‐year old stands of mainly meadow bromegrass (Bromus riparius)‐dominated haylands. All fertilization treatments produced significantly (P ≤ 0·05) higher dry matter yield than the control in the year of application at the three Saskatchewan sites. There was no significant difference between the two application methods (surface dribble band vs. coulter injected) for any fertilizer treatments. The addition of 28 kg P₂O₅ ha^?1 P fertilizer along with the N fertilizer did not have a significant effect on yield in most cases. In the year of application, increasing N rates above 56 kg N ha^?1 did not significantly increase yield over the 56 kg N ha^?1 rate in most cases, but did increase N concentration, N uptake and protein concentration. A significant residual effect was found in the high N‐rate treatments in 2006, with significantly higher yield and N uptake. In 2005, the forage N and P uptake in the fertilized treatments were significantly higher than the control in all cases. The N uptake at the three Saskatchewan sites increased with increasing N rate up to the high rate of 224 kg N ha^?1, although the percent recovery of applied N decreased with increasing rate. The P fertilization with 28 kg P₂O₅ ha^?1 also increased P uptake. Overall, rates of fertilizer of approximately 56 kg N ha^?1 appear to be sufficient to produce nearly maximum forage yield and protein concentration of the grass in the year of application.     

沼液与氮肥配施对小麦产量及品质的影响

为给小麦高产优质生产中沼液利用提供依据,在大田条件下,研究了沼液与氮肥配施对小麦籽粒产量及品质的影响.结果表明,在全生育期总施氮量240 kg·hm-2条件下,在基施化肥氮基础上追施沼液,尤其基施75％化肥氮和追施25％沼液氮配合处理(3/4U+1/4B)显著提高了淀粉糊化特性参数(峰值黏度、最终黏度、稀懈值和反弹值)、粉质参数(形成时间、稳定时间、粉质指数)和拉伸参数(拉伸面积、拉伸阻力和拉伸比).籽粒蛋白组分(总蛋白、球蛋白、醇溶蛋白和谷蛋白)含量以基施50％化肥氮和追施50％沼液氮配合处理(1/2U+1/2B)最高,3/4U+1/4B处理次之.籽粒蛋白组分、粉质与拉伸参数均以单施沼液处理(1/2B+1/2B)最低,单施化肥氮的处理(1/2U+1/2U)次之,而淀粉糊化特性参数以1/2U+1/2U处理最差,施用沼液的处理较1/2U+1/2U处理提高2.0％～6.5％.与1/2U十1/2U处理相比,基施沼液与追施化肥氮配合处理产量提高,而基施化肥氮与追施沼液氮处理的产量降低.可见在基施沼液的基础上追施化肥氮可提高小麦产量,其中1/2B+1/2U处理能够高产和优质兼顾,单施沼液效果低下.     

Soil chemical properties,plant species composition,herbage quality,production and nutrient uptake of an alluvial meadow after 45 years of N,P and K application

Little is known about the long-term effects of mineral N, P and K application on the nutritional status of mown alluvial grasslands. We asked how long-term fertilizer application affected soil chemical properties, plant species composition, herbage production, nutrient concentrations in soils and plants and balance of nutrients. Six treatments (control, PK, N50PK, N100PK, N150PK and N200PK) were investigated at the Černíkovice Experiment (Czech Republic) established in 1966 on an Alopecurus pratensis meadow, using annual application rates of 50, 100, 150 and 200 kg N, 40 kg P and 100 kg K ha⁻¹. Data were collected and analysed for 2007, 2008 and 2009. Although fertilizers had been applied over 45 years, differences in soil chemical properties between fertilization treatments were small. The legumes Lathyrus pratensis and Trifolium repens responded highly positively to PK application, and tall grasses, A. pratensis in particular, to NPK application. Herbage quality was high in terms of content of major nutrients, and its chemical properties varied considerably between treatments, cuts and years. Mean annual herbage yield ranged from 6·1 in the control to 9·7 t ha⁻¹ in the N200PK treatment. Herbage production was N-limited in 2007 and 2009, but not in 2008. Seasonal N agronomical efficiency ranged from 4·2 to 22·9 kg of DM herbage per kg of applied N. The herbage N:P and N:K ratios did not reflect the actual response of herbage production to N application. A negative balance between N applied and N removed in harvested herbage was recorded in all treatments. We concluded that in highly productive alluvial grasslands, mineral-rich soils can respond weakly to N, P and K application, fertilizer application modifies plant species composition and herbage production is not N-limited in all years. Nutrient ratios must be interpreted with caution for the estimation of nutrient limitation.     

氮素调控措施对小麦植株氮素同化过程和产量的影响

为明确不同氮素调控措施对小麦氮素同化过程和产量的影响,以皖麦68为试验材料,设置传统施肥+生物炭(CN+C)、传统施肥+硝化抑制剂(CN+D)、传统施肥+叶面肥(CN+P)、不施氮肥(CK)和传统施肥(CN)5个处理,分析各氮素调控措施与小麦叶片和茎秆的氮代谢物质含量、氮肥利用效率及产量等的关系。结果表明,与传统施肥相比,施用生物炭和硝化抑制剂能提高小麦体内铵态氮含量以及硝酸还原酶(NR)和谷氨酰胺合成酶(GS)活性,叶面喷肥能提高小麦灌浆期铵态氮含量和NR活性;各氮素调控措施能提高小麦灌浆期体内游离氨基酸和可溶性蛋白质含量,增强小麦的氮素转运速率和氮代谢水平,显著提高氮肥吸收利用率、氮肥农学效率和氮素偏生产力,进而提高小麦产量;施用生物炭、硝化抑制剂和叶面肥相比传统施肥分别增产568.3、520.0和663.3 kg·hm~(-2)。