供磷水平对不同磷效率玉米氮、钾素吸收和分配的影响

在砂培条件下,以磷高效利用型玉米(KH5)和磷低效利用型玉米(西502)为材料,研究了低磷(Pi25μmol/L,LP)和正常供磷(Pi2mmol/L,NP)2个供磷水平对其氮、钾素吸收和分配的影响。结果表明,磷高效利用型玉米氮钾素吸收和干物质积累受低磷处理的影响较小,表现出对氮、钾的高效吸收。正常供磷水平下,磷低效利用型玉米氮、钾素吸收量和干物质积累量显著高于磷高效利用型,但其氮、钾吸收和干物质生产能力远低于后者。低磷处理使玉米干物质和氮钾营养向根系分配的比例增加,磷低效利用型玉米这种趋势更为明显,反映其耐低磷能力较弱。     

钾对不同超高产小麦品种产量及氮、磷吸收效应的影响

通过大田试验和室内分析方法研究了潮土上钾对两个超高产小麦品种产量及氮、磷吸收效应的影响,结果表明:同一供钾水平下,温麦6号的的增产效果好于兰考906-4;钾与氮和磷之间存在着明显的正效应,而且耐低钾小麦品种更具有促进氮的吸收效应,使得氮、钾之间的相互促进作用表现得更为突出,这在一定程度上保证了作物高产对养分的需要。     

生姜对氮、磷、钾吸收分配规律研究

通过田间试验研究了高产生姜生长特性及对氮、磷、钾的吸收分配规律。结果表明,生姜幼苗期生长缓慢,虽持续时间占全生育期的52.6%,但干物质积累量较少,对N、P2O5、K2O的吸收速率较低,吸收量仅占全生育期的24%左右; 发棵期植株生长迅速,N、P2O5、K2O的吸收速率分别达3.5、1.3 和4.9 kg/(hm2·d),吸收量约占全生育期的30%左右; 根茎膨大期对N的吸收速率略有降低,而P2O5、K2O则仍分别高达1.3和5.1 kg/(hm2·d),N、P2O5、K2O吸收量分别占全生育期的44.0%、45.5%和47.1%。随生长的进行,N、P2O5、K2O在茎、叶中的分配率呈降低的趋势,而在根茎中的分配率则逐渐增加; 在根茎膨大期,根茎中的N、P2O5、K2O分配率分别达50.0%、61.0%和46.5%。生姜全生育期对N、P2O5、K2O的吸收比例约为2.5∶1.0∶3.8。本试验条件下,每生产1000 kg生姜根茎产品,分别吸收N、P2O5、K2O约4.67、1.90和7.25 kg。     

施锌对小麦开花后氮、磷、钾、锌积累和运转的影响

为明确大田条件下施锌对小麦地上部器官氮、磷、钾、锌的积累量和转移量的影响,2001～2002年开展了田间试验。试验以专用强筋小麦(8901-11)和普通小麦(4185)两个冬小麦品种为材料,包括4个施锌水平(分别为施ZnSO4.7H2O.0、11.25、22.5和33.75.kg/hm2)。结果表明,各器官中Zn的含量变化在4.14～54.18.mg/kg,刚开花时及灌浆前期的含量以子粒>穗壳>叶片>茎秆,至接近成熟时则以子粒>叶片>穗壳>茎秆。每生产100.kg小麦子粒需要吸收Zn的范围在4.40～5.20.g之间。小麦成熟时吸收的Zn约为N或K2O的1/800～1/700,为P2O5的1/500～1/300。施锌后小麦各器官氮、磷、钾、锌的积累量及开花后向子粒的运转量增加,但施锌过多,这些营养元素的吸收、积累和运转反而受到抑制。4185开花前吸收氮和磷的能力较强,而8901-11开花后吸收氮和磷的能力较强;而吸收钾和锌的能力与吸收氮和磷的情况相反。8901-11氮、磷、钾、锌的积累量基本随施锌量增加而提高,以施硫酸锌22.5～33.75.kg/hm2的积累量最高;而4185以施硫酸锌11.25.kg/hm2的积累量最高。因此,在施用大量元素的基础上,普通小麦以施硫酸锌11.25.kg/hm2为宜,而强筋小麦以施硫酸锌22.5～33.75.kg/hm2为宜。     

白首乌氮、磷、钾积累分配特点及其与物质生产的关系

在大田条件下研究了白首乌的干物质积累与植株氮、磷、钾积累的特点及其相互关系。对白首乌的干物质积累动态及植株氮、磷、钾含量进行了测定。结果表明,白首乌干物质积累总量随氮、磷、钾积累总量及养分平衡指数(NBI)的增加呈直线增加趋势,相关系数均达显著水平。不同时期白首乌对氮、磷、钾的吸收量不同,在移栽后60.d内对氮、磷、钾的吸收较少,仅占全部吸收量的16.8%、14.4%1、5.6%;移栽后601～20.d吸收量迅速增加,氮、磷、钾的吸收量占全部吸收量的68.7%5、2.3%、58.2%;移栽120.d之后又有所下降。总的来说,植株对钾的吸收量最多,氮次之,磷最少,全生育期内对氮、磷、钾的吸收比例为1∶0.8∶1.5。     

超高产夏玉米干物质与氮、磷、钾养分积累与分配特点

探讨超高产夏玉米品种整株干物质与氮、磷、钾养分积累分配特点,为制定高产栽培管理措施提供依据.本文在大田条件下,以登海661(DH661)和郑单958(ZD958)为试验材料,比较研究了超高产夏玉米干物质与氮、磷、钾养分积累分配特点.结果表明,超高产夏玉米DH661在成熟期内整株干物质及氮、磷、钾积累量分别为33475.53 kg/hm2、369.76 kg/hm2、117.85 kg/hm2、285.78 kg/hm2,均显著高于ZD958,较ZD958分别高15.82％、23.72％、32.17％、21.89％.超高产夏玉米DH661的干物质和氮、磷、钾养分在叶片和茎秆中的分配比例均低于ZD958,而籽粒和根系中的分配比例高于ZD958,因而具有较高的养分收获指数与偏生产力.整个生育期内,DH661各器官的养分吸收速率均显著高于ZD958,具有较高的养分吸收效率;茎、叶及根系的氮、磷、钾养分吸收速率在灌浆期前保持较高水平,之后下降较快,而籽粒的氮、磷、钾养分吸收速率于灌浆期后增加较快.吐丝期后,DH661仍能吸收积累较多的养分,因此吐丝后适当追肥对于超高产夏玉米灌浆期养分充足供应至关重要.     

半夏干物质积累与氮、磷、钾吸收特点的研究

在田间条件下,研究了一年内半夏二个生长季的干物质积累与氮、磷、钾积累的特点及其相互关系。结果看出,半夏植株在苗期干物质积累较慢,珠芽形成和块茎膨大期积累迅速,生长后期（倒苗期）则又减慢。植株对氮、磷、钾的吸收特点与干物质积累趋势基本一致。不同生长期半夏对氮、磷、钾的吸收量不同。在第一生长季,出苗后生长30 d内对氮、磷、钾的吸收量较少,分别占该生长季吸收量的30.6%,27.7%和27.8%;生长至60 d时吸收量迅速增加,分别占该生长季的43.6%,52.3%和49.0%;60 d以后其吸收量又逐渐减少。半夏第二生长季对氮磷钾的吸收特点与第一生长季的基本一致。表明半夏一年内以对氮的吸收量最多,钾次之,磷最少,氮、磷、钾的吸收比例为1﹕0.63﹕0.87。     

丹参氮、磷、钾积累分配特点及其与干物质、丹酚酸B积累的关系

田间条件下研究了丹参的干物质和丹酚酸B积累与植株氮、磷、钾积累的特点及其相互关系。结果表明,丹参干物质积累总量随氮、磷、钾积累总量的增加呈直线增加趋势,相关系数达显著水平。丹参的叶、茎的干物质积累在整个生育期内呈先上升后下降的趋势; 根部干物质积累呈上升趋势。在整个生育期内,丹酚酸B的积累趋势与丹参干物质积累趋势相似。不同时期,丹参对氮、磷、钾的吸收量不同。在移栽后30 d内对氮、磷、钾的吸收较少,分别占总吸收量的2.68%, 2.23%, 2.20%; 移栽后60~120 d 吸收量迅速增加, 氮、磷、钾的吸收量占全部吸收量的58.57%, 39.92%, 50.18%; 移栽120 d后又有所下降。总的来说,植株对氮的吸收量最多,钾次之,磷最少,整个生育期内对氮、磷、钾的吸收比例为1∶0.12∶0.46。     

不同施氮量及分配对小麦生长发育和产量的影响

不同施氮量及分配试验表明,未施氮素较施用氮素的小麦早熟６天,施用氮素（Ｎ,下同）３００ｋｇ／ｈｍ＾２,倒伏严重,产量低。以每公顷施２４０ｋｇ氮素,基肥：追肥＝６：４最好,分蘖比对照多０．５４个／株,有效穗比对照、施氮素１８０ｋｇ／ｈｍ＾２、３００ｋｇ／ｈｍ＾２分别多５１、４５、２７万／ｈｍ＾２,每穗粒数分别多１０．７、０．５、０．９粒,产量达８９７１．２ｋｇ／ｈｍ＾２,比对照、施氮素１８０ｋｇ／ｈ     

不同磷水平下小麦B染色体双端体植株干物质积累和磷效率特征研究

以中国春（CS）及其B染色体组双端体（1BS7BS和1BL7BL））为材料,采用溶液培养法,研究了不同磷水平下各供试材料的干物质积累和磷效率特征。结果表明,与CS相比,丰磷下4BS、6BS、3BL及7BL和低磷下4BS、6BS、7BS、和7BL植株形态及单株干重无明显变化,其他B染色体组双端体植株形态变劣、单株干重降低。丰、低磷下,各双端体单株磷累积量与CS相比多呈减少趋势,表明缺失B染色体长、短臂对小麦的磷素吸收和累积发挥不同程度负调控效应。全磷含量表现为丰磷下4BS和4BL较CS显著增加、5BS较CS显著降低;低磷下5BS较CS显著提高,3BL和5BL较CS显著降低。与CS相比,各双端体植株的磷效率变幅较大,呈与单株磷累积量相反趋势变化,即丰磷下3BS、5BS较CS显著增加,4BS、1BL和4BL较CS显著减少。丰、低磷条件下,多数双端体植株氮钾效率与CS相比也发生不同程度改变。丰、低磷磷下单株干重与磷累积量呈显著正相关,且单株干重与单株叶面积也呈显著正相关。因此,本研究证实,特定B染色体组长、短臂在调控植株抵御低磷逆境中发挥着重要遗传效应,可用单株叶面积作为丰、低磷下植株磷效率的评价指标。     

氮素水平对不同氮效率基因型水稻的物质生产与分配的影响

研究了在群体水培条件下,3种氮素水平(5、15和25mg.kg-1)对6种不同氮效率利用基因型迟熟中粳水稻物质生产与分配的影响。结果表明:氮素水平、基因型对水稻氮素干物质生产效率(NUEdm)、氮素籽粒生产效率(NUEg)均有极显著的影响。6种不同氮效率基因型可分成氮高效和氮低效利用型2类。NUEdm在2类基因型水稻中总体上均随着氮素水平升高呈现上升趋势;而NUEg在氮低效基因型中表现为随氮素浓度升高而先升后降。在水稻的4个关键生育期,不同氮素水平、2类基因型之间水稻干物质积累量差异显著。成熟期,氮素水平对水稻茎鞘、根、穗的干物质分配比例影响显著,对叶片干物质分配比例影响不显著。相同氮素水平下,就平均值而言,水稻茎鞘、叶片、根系干物质比例均表现为氮低效基因型>氮高效基因型,而穗的干物质比例均表现为氮高效基因型>氮低效基因型。氮素水平对不同基因型水稻产量影响显著,同一氮素水平下均表现为氮高效型基因型水稻产量显著高于氮低效型基因型,且施氮量越大差异越大。相关分析表明,水稻各关键生育期的干物质生产量、产量、每穗粒数均与氮素水平、基因型的NUEg、NUEdm显著或极显著相关,与成熟期水稻各器官干物质分配比例相关性则相对较弱。     

氮肥管理对小麦产量和氮肥利用效率的影响

氮肥过量施用造成环境污染和生产成本增加等问题已成为限制我国农业可持续生产的主要因素。为实现氮素化肥的高效利用,连续2年在山东省农业科学院作物研究所试验地同一地块利用氮肥梯度带,进行了基于小麦叶片SPAD值的氮素实时管理。结果表明,在基施区随着施肥量的增加,小麦籽粒产量增加,二者呈线性关系,但施氮量207kg/hm2(N207)和276kg/hm2(N276)处理间差异不显著;追施区小麦的2个生长季籽粒产量均以不施基肥拔节期追氮207kg/hm2(N0+207)处理最高,分别为7649kg/hm2和7522kg/hm2,基施氮肥207kg/hm2拔节期不追肥(N207+0)处理最低,仅为7318kg/hm2和7388kg/hm2,差异达显著水平(P<0.05)。基施区各氮肥处理的氮肥表观利用率(RE)和氮肥偏生产力(PFP)均存在显著性差异,均是随着基施量的增加而显著降低。追施区N0+207、N69+138、N138+693个处理的PFP、AE和RE均高于或显著高于N207和N276 2个处理。因此在确定总施氮量的条件下实行基、追肥分施能够显著提高小麦的氮肥表观利用率、氮肥农学效率和氮肥偏生产力。     

COURSE OF DRY MATTER AND NITROGEN ACCUMULATION OF SPRING WHEAT GENOTYPES KNOWN TO VARY IN PARAMETERS OF NITROGEN USE EFFICIENCY

Field experiments were conducted for two years to compare and identify bread spring wheat (Triticum aestivum L.) genotypes which make the most efficient use of nitrogen (N). Such information is required for breeding strategies to reverse the negative relationship between yield and protein content. Three Swiss spring wheat cultivars (‘Albis’, ‘Toronit’, ‘Pizol’) and an experimental line (‘L94491’) were grown without (N0; 0 kg N ha^?1) and with high fertilizer N [(NH₄NO₃); (N1; 250 kg N ha^?1) supply on a clay loam soil with low organic matter content. Biomass and nitrogen accumulation in biomass as well as the leaf growth and senescence patterns (SPAD) were investigated in an attempt to explain the physiology of growth and N translocation of these genotypes. The pre-anthesis accumulation of biomass and N in the biomass depended on genotype only at N1 in 2000. In this year, conditions were less favorable for the pre-anthesis accumulation of biomass and N, which was, on average, 10 and 20% lower, respectively, of the total than in 1999. The contribution of pre-anthesis assimilates to the grain yield (CPAY) was higher in 1999 for all genotypes (36.9%) compared to 2000 (13.5%) except ‘Toronit’. Between anthesis and maturity the climate influenced the genetic variability of some N use efficiency components: N translocation efficiency (NTE) and dry matter translocation efficiency (DMTE). NTE was higher in 1999 (68.1%) compared to 2000 (50.7%); 1999 was a year in which the post-anthesis period was drier and warmer than usual. ‘Toronit’ produced the highest biomass by maturity due mainly to greater and longer lasting green leaf area after anthesis. ‘Albis’ performed relatively well under low input conditions, with considerable amounts of N being re-translocated to the seeds at maturity (NHI), whereas ‘Pizol’ accumulated in grains N as high as for ‘L94491’. In a humid temperate climate breeding for greater N uptake and partitioning efficiency may be a promising way to minimize N losses and produce high phytomass and grain yields. Using high protein lines as selection material and combining them with high biomass genotypes may lead to high protein contents without decreasing yield.     

水肥对旱区马铃薯水分利用率的影响

采用裂区试验设计,以施钾水平为主处理,补水时期为副处理,研究了补充供水和钾素处理对马铃薯不同层次水分利用效率的影响,结果表明:马铃薯生育期耗水主要集中在80cm土层深度内,80cm土层以下土壤含水量变化不明显,基本不被马铃薯吸收利用。在氯化钾为150kg/hm2及苗期补水条件下,群体水平和产量水平水分利用率(WUE)均最高,分别为41.71和94.21kg/(mm.hm2),单叶水平WUE最低,但产量均为最高值(36324.97kg/hm2)。     

INFLUENCE OF DIFFERENT RATES OF PHOSPHORUS ON GROWTH,YIELD AND PHOSPHORUS USE EFFICIENCY IN TWO WHEAT CULTIVARS

To study the influence of different rates of phosphorus (P) on growth and yield of wheat, experiments were conducted at NIAB, Faisalabad, Pakistan under natural conditions. Results indicated that the P requirement of wheat at early growth was higher and adequate available P in the growth medium helped to attain relatively higher growth rate and resulted in higher grain yield. The two wheat cultivars when subjected to different rates of P application showed that the cultivar ‘MH-97’ was more responsive than ‘Pasban-90’ that attributed to its higher P translocation efficiency from roots to tops. The two cultivars also showed differential yield response when grown under field condition. At optimum nitrogen (N): P ratio of 1.5:1, the cultivar ‘MH-97’ gave 31.5% while cultivar ‘Pasban-90’ gave a maximum response of 25.9% over their respective N alone application. Contrarily, at the wider NP ratio of 3:1, yield response of cultivar ‘MH-97’ was 26.5% while that of cultivar ‘Pasban-90’ was only to the extent of 2.2%, thereby indicating a much wider difference in their yield response pattern. Thus, choosing an appropriate cultivar for a particular rate of fertilizer application would be more rewarding in terms of yield and profitability.     

施氮量对间作玉米土壤硝态氮累积量及氮肥利用率的影响

通过田间定位试验,监测了不施氮和不同施氮水平(分别为210、420和630kg.hm-2)下间作玉米各关键生育时期0～200cm土层硝态氮累积量的动态变化、玉米产量及其构成,计算分析了间作玉米的氮肥利用率。研究结果表明,间作玉米0～200cm土层土壤硝态氮累积量总体表现为0～60cm土层>60～200cm土层。0～60cm土层土壤硝态氮累积量呈"M"形变化,即玉米播种前和玉米大喇叭口期出现高峰,小麦播种前、玉米拔节期和玉米收获后出现低谷。60～120cm和120～200cm土层土壤硝态氮累积量呈倒"V"形变化,总体在玉米大喇叭口期前后出现高峰值,210～630kg.hm-2施氮处理下120～200cm土层的硝态氮累积量较不施氮处理分别高出149.1%、115.6%和126.3%。随着施氮量的增加,间作玉米穗长、穗粒数、穗重呈增大趋势,秃顶呈降低趋势,增产幅度依次减小,氮肥利用率依次降低。     

NITROGEN,PHOSPHORUS, AND POTASSIUM NUTRIENT EFFECTS ON GRAIN FILLING AND YIELD OF HIGH-YIELDING SUMMER CORN

A three-site-year field experiment was conducted to determine nitrogen (N), phosphorus (P), and potassium (K) fertilizer effects on grain filling dynamics and yield formation of high-yielding summer corn (Zea mays L.) in a wheat (Triticum aestivum L.)-corn double crop cropping system. Application of combined NPK fertilizers resulted in the greatest grain yield, largest grain number and grain weight when compared with the treatments receiving N, NP, or NK. Grain filling rate and duration, grain volume, and grain yield increased with NPK rates; however, doubling the rate of 180 kg N ha^?1, 40 kg P ha^?1, and 75 kg K ha^?1 fertilizer only led to minimal increases in grain filling rate (0.8%), grain filling duration (1.6%), grain volume (1.3%) and grain yield (0.4%). Our results suggested that for the high-yielding summer corn, a combined NPK fertilization is required to enhance grain filling and yield, and that under well-fertilized circumstances, limited increases in both grain filling and sink capacity might be the main factor restricting further yield improvement.     

WATER STRESS AND NITROGEN MANAGEMENT EFFECTS ON GAS EXCHANGE,WATER RELATIONS,AND WATER USE EFFICIENCY IN WHEAT

A field experiment was conducted over two years to evaluate the gas exchange, water relations, and water use efficiency (WUE) of wheat under different water stress and nitrogen management practices at Crop Physiology Research Area, University of Agriculture, Faisalabad, Pakistan. Four irrigation regimes and four nitrogen levels, i.e., 0, 50, 100, and 150 kg N ha^?1 were applied in this study. The photosynthetic gas exchange parameters [net carbon dioxide (CO₂) assimilation rate, transpiration rate and stomatal conductance] are remarkably improved by water application and nitrogen (N) nutrition. Plants grown under four irrigation treatments as compared with those grown under one irrigation treatment average stomatal conductance increased from 0.15 to 0.46 μ mol m^?2s^?1mol during 2002–2003 and 0.18 to 0.33 μ mol m^?2s^?1mol during the year 2003–2004 and photosynthetic rate from 9.33 to 13.03 μmol CO₂ m^?2 s^?1 and 3.99 to 7.75 μmol CO₂ m^?2 s^?1 during the year 2002–2003 and 2003–2004, respectively. The exposure of plants to water and nitrogen stress lead to noticeable decrease in leaf water potential, osmotic potential and relative water content. Relative water content (RWC) of stressed plants dropped from 98 to 75% with the decrease in number of irrigation and nitrogen nutrition. The higher leaf water potential, and relative water contents were associated with higher photosynthetic rate. Water use efficiency (WUE) reduced with increasing number of irrigations and increased with increasing applied nitrogen at all irrigation levels.     

ENHANCING NITROGEN USE EFFICIENCY BY COMBINATIONS OF NITROGEN APPLICATION AMOUNT AND TIME IN WHEAT

Nitrogen (N) is one of the most important impact factors on development and growth of wheat. In this study the effects of nitrogen use efficiency on quantity and quality of grains were studied by agronomic management of N fertilizers on spring wheat (Triticum aestivum L.) grown under field conditions for two years. The experiments were performed at 16 combinations of N application amount and time, including four levels of N at 0, 60, 120 and 180 kg N ha^?1 that were used as pre-plant fertilizers, sub-treated with four levels of the same N amount used as top-dress fertilizers. As a result, with an increase in total N fertilizers, grain yield increased in a cubic equitation, but partial factor productivity (PFP_N, kg grain yield per kg N applied) decreased exponentially. With total fertilizers, N content and accumulation in vegetative tissues and grains increased linearly, but N uptake efficiency (UtE_N, kg nutrient taken up per kg N applied) decreased exponentially. When N was over-applied (>360 kg N ha^?1 in this study), grain yield clearly declined, due to decrease in productivity from per unit N. The high N level (240～300 kg N ha^?1), the reasonable distribution between pre-plant and top dress from the same amount N fertilizer not only increased grain yield but also enhanced N use efficiency.     

PHOSPHORUS UPTAKE AND USE EFFICIENCY IN FIELD CROPS

Phosphorus (P) is required by crop plants for many physiological and biochemical functions. Knowledge of phosphorus uptake and its use by crop plants is essential for adequate management of this essential nutrient. A field experiment was conducted during four consecutive years to determine P uptake and use efficiency by upland rice, dry bean, corn and soybean grown in rotation on a Brazilian Oxisol. Plant samples were taken at different growth stages during the growth cycle of each crop for phosphorus analysis. Phosphorus concentration (content per unit dry matter) significantly decreased in a quadratic fashion with the advancement of plant age in four crop species. Phosphorus concentration was higher in legumes compared to cereals. Phosphorus uptake in shoot, however, significantly increased in an exponential quadratic fashion with the advancement of plant age of crop species. At harvest, P uptake was higher in grain compared to shoot, indicating importance of this element in improving crop yields. Phosphorus use efficiency (grain or straw yield per unit P uptake) was higher in cereals compared to legumes. The P use efficiency for grain production was 465 kg kg^?1 for upland rice, 492 kg kg^?1 for corn, 229 kg kg^?1 for dry bean and 280 kg kg^?1 for soybean. The higher P use efficiency in cereals was associated with higher yield of cereals compared to legume species.