Agronomic Performance and Nutrient Concentration of Maize (Zea mays L.) as Influenced by Nitrogen Fertilization and Plant Density

A field experiment was conducted at Samaru, Nigeria to study the influence of nitrogen fertilization and plant density on the agronomic performance and nutrient concentration of maize ( Zea mays L.). The treatments were factorial combinations of five nitrogen fertilization rates (0, 50, 100, 150 and 200 kg N/ha) and three plant density levels (25000, 50000 and 75000 plants/ha).
Nitrogen fertilization up to 150 kg N/ha enhanced grain and stover yields and increased kernel number and weight up to 100 kg N/ha. Nitrogen supply also increased maize ear length. Increased N fertilization rates increased concentrations of N, K and Mg but had no effect on P and Ca concentrations. Higher grain yield was closely associated with higher N concentration in ear leaf; with 0.1 % change in N concentration causing 177 kg/ha change in grain yield. Increased plant density increased stover yield up to 50 or 75 thousand plants/ha but depressed kernel number and weight and ear length.     

The Influence of Row Spacing and Seeding Rate on Seed Yield and Yield Components of Forage Turnip (Brassica rapa L.)

The effects of four row spacings (17.5, 35.0, 52.5 and 70.0 cm) and five seeding rates (50, 100, 200, 400 and 800 viable seeds m^?2) on seed yield and some yield components of forage turnip (Brassica rapa L.) were evaluated under rainfed conditions in Bursa, Turkey in the 1998–1999 and 1999–2000 growing seasons. Plant height, stem diameter, pods/terminal raceme, total pods/plant, seeds/pod and primary branches/plant were measured individually. The number of plants per unit area was counted and the lodging rate of the plots was scored. The seed yield and 1000‐seed weight were also determined. Row spacing and seeding rate significantly affected most yield components measured. The number of plants per unit area increased with increasing seeding rate and decreasing row spacing. Plant height was not greatly influenced by row spacing and seeding rate, but higher seeding rates reduced the number of primary branches and the stem diameter. The number of pods/main stem was affected by row spacing and but not by the seeding rate. Also, the number of seeds per pod was not affected by either the row spacing or the seeding rate. In contrast, the number of pods per plant clearly increased with increasing row spacing, but decreased with increasing seeding rate. The plots seeded at narrow row spacings and at high seeding rates were more sensitive to lodging. Seeding rate had no significant effect on seed yield in both years. Seed yield was similar at all seeding rates, averaging 1151 kg ha^?1. However, row spacing was associated with seed yield. The highest seed yield (1409 kg ha^?1) was obtained for the 35.0‐cm row spacing and 200 seeds m^?2 seeding rate combination without serious lodging problems.     

不同株行配置与密度对油菜产量的影响

本文系统地研究了4种不同种植密度条件下,3种等行距、3种宽窄行共6种株行配置对油菜经济性状和产量的影响差异,结果表明：不同株行距配置方式对密度在15×104株/hm2油菜产量影响不显著,但对密度45×104株/hm2油菜影响达极显著水平,适宜株行距配置增产效果最高达到19.1%;认为20 cm~40 cm的行距配置有利于当前较高密度直播油菜的生产。     

Water Stress and N Fertilization Effects on Yield and Smut Disease Incidence in Corn (Zea mays L.)

A 2-year field experiment was conducted in sandy clay loam soil to quantify the single and combined effects of N fertilization and water stress (WS) treatments on yield and smut incidence in corn. The plants were supplied with two different N rates (225 and 300 kg ha⁻¹) and subjected to 2 weeks' water stress, imposed at vegetative (Vg), tasselling (Ta), silking (Si) and grain-filling (Gf) growth stages. In addition, a control treatment (Cr) was also included to allow the plants to grow under unstressed conditions. The plants were artificially infected two times with Ustilago maydis spores and smut severity was recorded. At harvest, grain yield (GY), total biomass (Tbm) and harvest index (HI) were determined in smut-free (0) and smutted plants (S). Results have shown that GY₀ and GY_s were markedly reduced when the plants were subjected to WS. The depressing effects of WS were, comparatively, high at Gf. intermediate at Ta and Si. and low at Vg growth stages. Smut index (SI) data revealed that severity was higher on plants stressed at Gf than those exposed to WS at Vg, Ta or Si stages. Considerable variations were detected on Tbm and HI of smut-free and smutted plants, indicating the detrimental effect of plant water deficit at Gf stage. The combined effect of WS and N on Tbm_s showed mixed results, ranging from positive response for stressed plants at Si and Gf to little response at Cr, Vg or Ta stages at higher N rate. Although the effect of WS exposure on RYL data was dominant at Gf, the rate of yield depression was relatively higher at Ta and Si than the other growth stages, because of water deficit effects. The results proved that N fertilization did not conclusively alleviate the depressing effect of WS on grain yield losses.     

Role of Sulphydryl Compounds in Improving Dry Matter Partitioning and Grain Production of Maize (Zea mays L.)

Three sulphydryl compounds, viz., 2-mercaptoethanol, 2-mercaptoethylamine and thiourea, were tested for improving dry matter partitioning and grain production of maize in field culture. The chemicals were applied ca. 0.1 % concentration as foliar spray at grain formation stage. Mercaptoethanol, mercaptoethylamine and thiourea increased grain yield ha⁻¹ by 18.1, 29.2 and 34.1 %, respectively compared with water control Significant improvement in harvest index, a measure of dry matter partitioning for grain production, was also noted with the spray chemicals but stover and biological yields ha⁻¹ remained uninfluenced. Foliar spray of 0.1 % urea did not have any effects on the above parameter and thus the effects of thiourea were largely a function of sulphydryl group. It is suggested that sulphydryl compounds have a considerable potential for increasing grain production of maize and perhaps of similar other cereals.     

鲜食型糯玉米(Zea mays L.)产量和出籽率的配合力分析

为了进行鲜食型糯玉米(Zea mays L. sinensis Kulesh)种质资源的创新、改良加工品质、选育优质高产的新品种。本试验以7个糯玉米自交系为亲本,按照GriffingⅣ配制21个杂交组合,分析了糯玉米产量和出籽率的配合力效应。结果表明,糯玉米的产量和出籽率受加性基因和非加性基因共同控制;7个亲本的产量一般配合力效应大小顺序为N23>N17>N28>N47>N51>N15>N27,出籽率一般配合力效应大小值为N51>N27>N47>N23>N28>N17>N15;综合一般配合力效应及特殊配合力效应结果表明,N15×N23是相对高产的组合;N27×N51是出籽率相对较高的组合;对自交系综合评价表明,N23、N17可作为选育高产优良组合的理想亲本,N27可作为选育高出籽率的理想亲本。本研究结果可为糯玉米育种实践提供一定的参考。     

Smut Disease and Yield Performance in Corn (Zea mays L.) as Influenced by Nitrapyrin, Urea and Zinc Applications in Coarse-textured Soils

The effects of nitrapyrin (NI), urea (U) and Zn rates on rhizosphere pH, smut incidence (S.I.), dry matter (D.M.), grain yield (G.Y.) and ear leaf N and Zn contents were studied in cemented plots, containing calcareous and non-calcareous soils. Treatments were comprised of 3 U applications (46, 92 and 138 kg N acre⁻¹), combined with 2 NI rates (0 and 0.22 kg acre-¹) and 2 levels of Zn (0 and 8 kg acre-¹). Corn seeds, cv 'Amoun' were planted in 1993 and 1994 and the seedlings were artificially infected with U. maydis-spores at the 6 and 10 leaf growth stages. Results have shown that corn plants grown in calcareous soil imposed greater advantage in D.M. and G.Y., accompanied by a relatively low smut infection than those grown in non-calcareous soil. Unlike the diversion effects of NI on soil pH and plant Zn content, its application was beneficial for improving yield and plant Zn content. Urea applications decreased the soil pH by 0.6 unit at the highest N rate and exerted stimulatory effects on ear leaf N and Zn contents. By increasing U rate to 138 kg N acre-¹, smut severity was increased by 6%. In contrast, by Zn fertilization, smut severity was decreased by 10.3%, accompanied by marked increases in G.Y. and leaf Zn content. Mixed results were detected on S.I. data, when NI was combined with U rates. In the presence of Zn, smut severity was dropped to 20.1% at 138 kg N acre-¹. The results also showed that in the absence of Zn supply, S.I. was dominated in NI-treated plants and the reverse was true when Zn was included. Satisfactory results were achieved when 92 kg N acre-¹ were combined with 0.22 and 8 kg acre-¹ of NI and Zn, respectively.     

行距配置和种植密度对薏苡光合生理、籽粒灌浆及产量的影响

为薏苡高产栽培提供参考依据,采用2 因素裂区设计,设置2 种行距（等行距、宽窄行）和4 种密度（7 万、6 万、5 万、4 万株/hm2）,研究不同的种植方式对薏苡花后光合生理、籽粒灌浆及产量的影响。结果表明：宽窄行种植改善了薏苡的群体结构,提高了叶片光合性能和籽粒灌浆能力,与等行距种植的薏苡相比,4 种密度种植的薏苡产量分别提高7.87%、7.90%、7.87%和8.75%;种植密度对薏苡产量影响显著,2 种行距配置的薏苡都以种植密度为5 万株/hm2时产量最高,分别达到4544.1、4901.9 kg/hm2。薏苡的适宜种植密度为5万株/hm2,宽窄行种植是薏苡高产栽培的有效措施。     

三个超高产夏玉米品种的物质生产及光合特性

探明不同株高、穗位高具有超高产潜力(>15 000 kg hm^-2)夏玉米品种的物质生产及光合特性,有利于密植增产。本研究在多年高产试验基础上(连续3年达15 000 kg hm^-2以上),选用了登海661 (DH661,低秆低穗位)、登海701(DH701,中秆中穗位)和先玉335 (XY335,高秆高穗位) 3个具有超高产潜力的品种进行试验。在一般高产条件下,这3个品种间产量无显著差异,但干物质生产特性的模型解析表明,DH661的产量潜力高于DH701和XY335,其活跃生长期比XY335长近3周。开花后光合特征参数显示,DH661光合作用与光能利用效率明显较高,尤其是当XY335进入生理功能速衰期时(开花后28 d),DH661仍处于缓慢下降阶段,且具有较高的光合速率和光能利用效率,DH661的这一特性表明其具有更高的产量潜力。     

不同行株距（密度）对小黑豆产量及其相关性状变异系数的影响

为了高效开发利用小黑豆资源,提高小黑豆产量,在山西隰县采用随机区组设计方法研究了不同行株距（密度）对小黑豆产量及相关性状变异系数的影响。结果表明：行距40 cm的平均产量优于行距60 cm的平均产量;不同行株距配置（密度）中,R40P30（8.34万株/hm2）处理的籽粒产量、单株籽粒产量、单株荚数和结荚高度4个性状均优于其他处理,R60P15（11.12万株/hm2）处理的百粒重性状优于其他处理,株高性状以R60P25（6.67万株/hm2）处理最高不,同行株距配置（密度）对有效分枝性状不存在影响;不同行株距配置（密度）处理对各性状的变异系数影响序列为产量>结荚高度>单株籽粒产量>百粒重>单株荚数>有效分枝>株高。该项研究为进一步提高小黑豆产量提供了理论和技术支撑。     

Yield and Agronomic Characters of Tropical Maize (Zea mays L.) Cultivars under Different Irrigation Regimes

Drought spells are unpredictable under tropical conditions and can occur at every growth stage of the maize plants. Little is known about the reactions of tropical maize cultivars to water shortage. A set of Thai cultivars was examined in the field during the dry season. Three stress situations were imposed: prolonged stress throughout the growing season, pre- and post-anthesis stress. Pre-anthesis water stress delayed flowering and especially the data of silking. Thus, the anthesis-silking interval was wider. Prolonged water stress decreased grain yield mainly due to a low number of kernels and/or thousand kernel weight (TKW). Post-anthesis stress mainly reduced TKW grain set per ear. Relief from pre-anthesis stress increased grain yield by a grater number of kernels and higher TKW as compared to prolonged stress. Genotypic differences were high for the anthesis-silking interval following pre-anthesis stress. Low yielding, early but generally drought-stable cultivars existed as well as cultivars which were generally high yielding even under water stress because of a good residual yield. Some cultivars were resistant to pre-anthesis stress but not to post-anthesis stress and vice versa. It can be concluded that ample genotypic variability exists for adaptation to varying situations of pre-and post-anthesis stress within tropical maize cultivars.     

新疆机采模式下棉花株行距配置对冠层结构指标及产量的影响

【目的】为了研究不同株行距配置对机采棉花冠层结构指标及产量的影响。【方法】在田间条件下,选用棉花杂交种鲁棉研24号和常规品种新陆早60号为供试材料,设置适宜机采的1膜3行等行距(76 cm+76cm+76 cm)低密度、1膜6行宽窄行(66 cm+10 cm)高密度及1膜3行等行距(76 cm+76 cm+76 cm)双株高密度3种配置方式进行试验。【结果】等行距低密度下,棉花生育前期生长旺盛,叶面积指数与光吸收率迅速增加至最高值;生育后期,叶面积指数及光吸收率下降幅度分别为10.4%~13.6%、3.7%~4.2%,低于其他两种处理,且干物质积累量较高。等行距低密度下杂交棉产量最高。【结论】等行距低密度下杂交棉实现高产的生理基础主要是:生育前期叶面积指数及光吸收率增长迅速,干物质积累较快;生育后期叶面积指数及光吸收率下降缓慢,能维持较高水平,光合生产能力较高,干物质积累量最大。     

Timing of Nitrogen Application to Enhance Corn (Zea mays, L.) Yields in a Desert Climate

Experiments were conducted in two consecutive years to investigate the response of two corn (Zea mays, L.) cultivars, Eperon and Challenger, to timing of N fertilizer in a desert climate. Fertilizer was applied three times (at planting, 6 weeks after sowing (6WAS) and at 9WAS) to give a seasonal total of 180 kg N ha^-1 The N treatments were N_ooo (control), N_LOH (60 kg N ha^-1 at planting, none at 6WAS and 120 kg N ha^-1 at 9WAS), N_LLL (60 kg N ha^-1 at sowing, 6WAS and at 9WAS) and N_LOH, (60 kgN ha^-1 at planting, 120 kg N ha^-1 at 6WAS and none at 9WAS). Generally, N ha^-1 was associated with the highest grain and dry matter yields. Plants in N treated plots had significantly larger number of leaves and ear leaf N contents than the control at mid-silk. High ear leaf N was associated with high leaf area index and dry matter yield. Based on these results, it would appear that the application of 60 kg N ha^-1 at planting, followed by 120 kg N ha at 6WAS (N_LHO) is the most suitable for enhancing corn yields in the desert climate.     

Effects of Thiourea, Thiamine and Ascorbic Acid on Growth and Yield of Maize (Zea mays L.)

Three chemicals, viz., thiourea, thiamine and ascorbic acid capable of potentiating-SH turnover, were tested with the objective to improve growth and productivity of maize. Thiourea was tested as seed-soaking and foliar-applied treatments as also in combination. Thiamine and ascorbic acid were tested as foliar sprays alone. Foliar treatments were applied at vegetative stage (30 and 45 days after sowing).
The results of the field experiment showed that seed soaking with thiourea (500 ppm) tended to improve grain yield (13.4 per cent over control), but improvement in biological yield was significant. However, seed soaking plus foliar treatment of thiourea significantly increased both biological and grain yields, besides causing significant improvement in leaf area index and number of green leaves plant^-1. The increase in grain yield ha^-1 was of the order of 34.6 per cent over control.
It was further noted that foliar sprays of thiourea (1000 ppm), thiamine (100 ppm) and ascorbic acid (100 ppm) significantly increased leaf area index, number of green leaves plant^-1 and biological yield ha^-1. These treatments also significantly increased grain yield ha^-1 by 40.6, 20.2 and 26.3 per cent, respectively over control. Improvement in maize yield with thiourea, thiamine and ascorbic acid treatments appeared to have resulted from increased photosynthetic efficiency and canopy photosynthesis on account of the biological activity of -SH group. It was also apparent that leaf senescence was delayed under the influence of these chemicals. It is therefore suggested that thiourea, thiamine and ascorbic acid are the potential bioregulators for improving photosynthetic efficiency and grain yield of maize and possibly other cereals, and that thiourea, a sulphydryl compound, holds considerable promise in this context.     

不同地力水平下控释尿素对玉米物质生产及光合特性的影响

氮肥是玉米生产中最重要的增产要素之一。为探明不同地力水平下控释尿素对玉米物质生产及光合特性的影响, 采用盆栽试验研究了释放期不同的2种控释尿素(CRU₃₀, 释放期为30 d; CRU₆₀, 释放期为60 d)的作用效果, 以普通尿素为对照(U)。结果表明, 控释尿素处理显著增加玉米干物质积累量, 但释放期不同的控释尿素在不同地力水平下增产效果不同, 低地力水平下增产效果为CRU₃₀>CRU₆₀>U (P<0.05), CRU₃₀处理比施用普通尿素增产18.9%; 高地力水平下增产效果为CRU₆₀>CRU₃₀>U(P<0.05), CRU₆₀处理比U增产18.2%。与对照相比, 控释尿素使干物质向开花后分配比例增加, 氮肥偏生产力(PFPN)显著提高, 低地力时CRU₃₀最高, 而高地力时CRU₆₀最高。控释尿素处理的单株干物质积累量、穗粒数及千粒重显著增加, 主要因为生育中后期叶面积、光合速率、叶绿素及叶片氮含量维持较高水平。所以, 在等氮量做基肥一次性施入时, 低地力水平下施用释放期较短的控释尿素为宜, 而高地力水平下应施用释放期较长的控释尿素。     

缺苗断垄对机播夏玉米产量及产量构成因素的影响

为探讨缺苗断垄对机械化播种夏玉米的影响,在大田状态下设置2个品种不同缺苗断垄程度进行试验,并对缺苗级别、断垄级别、籽粒产量及其产量构成因素进行统计分析。结果表明,缺苗断垄引起产量降低的主要原因是株数和穗数减少,随着缺苗断垄级别的增加,株数穗数逐渐减少,产量逐渐降低。产量降低幅度小于缺苗断垄级别的增加幅度,在缺苗断垄率为10.00%～40.00%的情况下,产量降低幅度为3.60%～28.51%;在缺苗断垄率相同的情况下,鲁单981比郑单958的减产幅度大些。     

密度及行距配置对‘丰油10号’生长发育、产量和品质的影响

为了探究‘丰油10号’在黄淮地区适宜的播种密度与行距配置。在河南省油菜主产区进行大田试验,比较不同种植密度及行距配置方式下,‘丰油10号’的物候期、叶片叶色值(specialty products agricultural division, SPAD)及开花期叶面积指数(leaf area index, LAI)、经济性状、产量和品质情况。结果表明：‘丰油10号’的生育期随着密度和行距的增大,逐渐缩短;叶片的SPAD值在蕾薹期和开花期随密度增大逐渐降低,随行距缩小而减小;植株LAI在开花期随着密度的增大先增后减,同一密度下,40 cm行距下较高;株高、一次有效分枝数、主花序的长度和角果数随密度的增加逐渐较小,分枝部位则升高,随行距的减小单株有效角果数下降,千粒重不受密度和行距配置的影响;籽粒产量和含油量随着种植密度的增加先增后减,籽粒产量在种植密度为42万株/hm²,40 cm行距下最高,为2734.6 kg/hm²,当行距缩小到20 cm,籽粒平均减产4.65%;籽粒芥酸和硫苷含量不随密度和行距改变发生变化。在其它栽培措施保持不变的情况下,建议‘丰油10号’在黄淮流域的种植密度控制在34.5万~49.5万株/hm²,行距设置为40 cm。     

行距对棉花生长发育、产量及早熟性指数的影响的研究(英文)

棉花窄行密植生产是缩短棉花生长季节实现棉花早熟的主要举措,并且窄行密植对棉花的产量无显著影响。田间试验于2006年6月到2007年1月在巴基斯坦费萨拉巴德农业大学试验田进行,以确定行距对不同品系棉花的生长、生产和早熟性指数的影响。试验选取NIAB-111,CIM-496和FH-901 3个棉花品种,设置了60、75和90 cm 3种行距进行试验研究。结果表明:行距对棉花生长发育、产量和早熟性指数具有极显著影响;行距75 cm的处理产量最高达到2603 kg·hm-2,其次是行距60 cm的处理,产量为2541 kg·hm-2,但二者间差异不显著;行距60 cm的处理早熟性指数达到50.92%,显著大于其它处理;行距75 cm的处理次之。子棉产量最高的品种是FH-901,同时其早熟性指数也最高,达到54.34%。     

Productivity of Maize (Zea mays L.) in Relation to Morphological and Physiological Characteristics under Varying Amounts of Nitrogen Supply

In a field trial located in a northern region of Germany, characterized by a Podzol soil and increasing N fertilization resulted in an enhanced N uptake of the maize (Zea mays L.) variety “Felix” with increasing N fertilization ranging from 0 kg N ha^-1 (N1) to 60 kg N ha^-1 (N2) and to 160 kg N ha^-1 (N3). The growth conditions reached only nearly optimal temperature for biomass allocation in a short period of July and August 1990. The plant productivity was stimulated due to higher N uptake and N utilization to values of nearly 1600 g ha^-1. The N efficiency decreased with increasing N fertilization. A greenhouse experiment was conducted to study the effects of varied nitrogen nutrition on the development of maize plants under standardized growth conditions, comparable to the sub optimal growth conditions of the field experiment. Physiological and anatomical parameters were measured. Within a range of 0.2—1.0 mg N cm^-2 of leaf nitrogen, the chlorophyll concentration and the CO₂ exchange rate showed a linear relationship with the reduced N in the leaf. Above 1.0 mg N cm^-2 no further increases in chlorophyll levels or photosynthesis were observed. Nitrate reductase activity was stimulated throughout the N range supplied. The activities of photosynthetic enzymes (PEP carboxylase, Nadp malic enzyme, RubP carboxylase) was increased from the low (0.19 g N kg^-1 soil) to the middle N level (0.37 g N kg^-1 soil). Under conditions of a high N supply (0.75 g N kg^-1 soil) the activity decreased, except Nadp malic enzyme. This effect was accompanied by alterations of the internal structure of the leaf. Leaf thickness and size of the mesophyll parenchyma were less at the medium nitrate supply. Other anatomical parameters were influenced in proportion to leaf nitrogen status. Stomatal index was not affected by N supply, but lengths and widths of epidermal and stomatal cells as well as the distance between stomata and vascular bundles were increased by high N supply. It is proposed that above an optimal range of leaf nitrogen, maize plants cannot use the potential advantage of the C₄ mechanism and the N utilization shows maximum efficiency in the intermediate N level under the sub optimal growth conditions used in the greenhouse experiment.     

不同密度与行距配置对紧凑型玉米产量效应的研究

以郑单958为试材,研究了不同密度和行距配置方式下玉米产量变化规律,结果表明：不同行距间、不同密度间及不同行距与密度互作间产量均存在极显著差异,适度增加密度可以提高产量,随行距的扩大产量有降低的趋势,对紧凑型玉米而言,产量不仅与种植密度密切相关,而且与种植方式也有一定关系。