共查询到20条相似文献，搜索用时 46 毫秒
1.
Effect of planting date on severity of frogeye leaf spot and grain yield of soybeans 总被引：1，自引：0，他引：1
The influence of soybean (Glycine max) planting date on seasonal epidemics of frogeye leaf spot caused by Cercospora sojina and on grain yield, was evaluated during the 1991 and 1992 cropping seasons. Two susceptible (Samsoy 1 and TGx 849-313D) and one resistant (TGx 996-26E) soybean cultivars were used in field trials at Zonkwa, in the southern Kaduna state of Nigeria. Four field plantings were made at 14-day intervals from late May to mid0July. For each planting date, half the plots received foliar applications of benomyl at R1 and R3 growth stages, and the other half was untreated. Frogeye disease severity ratings were taken for all plots at R4 to R5 growth stages, and grain yield for each plot was measured at harvest. There was a significant (p < 0.05) increase in disease severity between the first and third plantings on the two susceptible cultivars in 1991, and on TGx 849-313D only in 1992. Corresponding yield reductions for the two susceptible cultivars averaged 13 and 31% for the treated and untreated plots, respectively, with each 2-week delay beyond the first planting date in 1991, and 5 and 6%, respectively, in 1992. There was no significant difference in disease among all treatments on the resistant cultivar, TGx 996-26E. Under Nigerian conditions, an increase in frogeye leaf spot severity can be expected with delayed planting of soybean after 1 June, and this can result in a corresponding loss of crop yield. 相似文献
2.
《Field Crops Research》2001,72(2):109-118
Seed and pod numbers are the main yield components in soybean (Glycine max (L.) Merrill). They are related to canopy photosynthesis during a critical period, occurring between the R1 (beginning of flowering) and R6 (full seed) stages. We investigated the relationship between the duration of the critical period and the number of seeds produced. Response to photoperiod during post-flowering stages was evaluated in indeterminate soybean cultivars from maturity groups (MG) IV and V. The study was conducted under field conditions with two sowing dates (normal and late). Plants were grown under natural photoperiod throughout the experiment or exposed, from the R3 stage (beginning pod) onwards, to artificially extended regimes of 2 h longer than natural daylength. Duration of the R3–R6 period increased in response to the extension of photoperiod, and cultivars of MG V exhibited a stronger sensitivity to photoperiod than those of MG IV. Exposure to long photoperiods promoted node production, mainly in branches, and increased node fertility. Within each sowing date, the increased duration of R3–R6 under longer photoperiods was corresponded with increments in pod and seed number. Seed number was related to the duration of R3–R6, particularly when the length of the period was corrected for temperature differences between treatments. Seed number was also related to the integral of solar radiation during R3–R6. The possibility of using sensitivity to photoperiod after flowering as a criterion for increasing yields through increasing seed number are discussed. 相似文献
3.
在小麦生产中,倒伏对其产量影响较大。为达到控高及稳产的目的,选用3种常用的抗倒剂(25%矮壮丰、3%调环酸钙水乳剂、5%抗倒酯水乳剂)来探究其对小麦生长及产量的影响。结果表明,与常规对照R2(矮壮丰80 m L/667 m2)相比,在灌浆期(5月12日)前,其他抗倒剂处理下小麦的叶绿素含量大都低于对照,而灌浆期后下降缓慢,光合作用时间延长;抗倒剂处理下小麦的株高都低于对照且在R6(抗倒酯水乳剂60 m L/667 m2)处理下降至最低,且小麦的不同节间长度在抗倒酯水乳剂处理下都得到控制,在最高浓度(60 m L/667 m2)处理下都降至最低;调环酸钙水乳剂仅对小麦的第3、第5节间有控长作用,而抗倒酯水乳剂对小麦的大部分节间都起到控长作用。从产量方面来看,有效穗数在R6(抗倒酯水乳剂60 m L/667 m2)处理下达到最高,实粒数在不同处理下相差不大,结实率和千粒质量在抗倒酯水乳剂处理下都处于较高水平,但产量在常规对照R2(矮壮丰80m L/667 m2)处理下最高;其次是R6(抗倒酯水乳剂60 m L/667 m2)处理。因此,综合考虑控高效果、有效穗数和千粒质量提高及稳产等多种因素,推荐在小麦的分蘖末期喷施60 m L/667 m2的5%抗倒酯水乳剂,能达到控高且不会明显降低其产量的目的。 相似文献
4.
晚播对菜用大豆根系、干物质积累及鲜食产量的影响 总被引：1，自引：0，他引：1
播期是大豆高产栽培管理的重要手段.利用正常大豆播种期为对照,研究了三个相对晚播日期对菜用大豆物候期、根系、干物质及鲜食产量的影响.结果表明:晚播明显缩短生育期,播期越晚,播种到出苗的时间越短,整个生育日期越短,晚播能促进营养生长,增加苗期干物质的积累,但显著降低苗期根表面积和减少根长,根冠比下降.晚播也显著增加地上干物质的积累,6月14日播种R6期的干物重最高为:51.1g·株-1.适当的晚播可有利于菜用大豆的鲜荚产量形成.6月4日和6月14日播种R6期后10 d鲜荚产量最高,可作为哈尔滨地区的菜用大豆的适宜播期. 相似文献
5.
针对我国甘蔗生产中氮肥用量高和氮肥利用率低的问题,为提高氮肥利用率,本研究以‘桂糖42号’为试验材料,研究对比5种施氮量（N150：150 kg/hm2、N225：225 kg/hm2、N300：300 kg/hm2、N375：375 kg/hm2、N450：450 kg/hm2）和2种施氮次数（R1：3次施入,30%氮肥作基肥、30%作分蘖肥和40%作攻茎肥;R2：2次施入,30%氮肥作基肥和70%作攻茎肥）下宿根蔗生长、产量、含糖量以及氮素利用。结果表明：（1）蔗茎产量受施氮量影响显著,随施氮量增加,2种施氮次数的蔗茎产量均呈现递增趋势。相同施氮量下,不同施氮次数的蔗茎产量差异不显著,R1N375、R1N450、R2N375和R2N450处理甘蔗产量较高,分别为106.4、112.2、106.4和109.1 t/hm2。（2）随施氮量增加,蔗糖分先增加后减少。N375和N450下,R1的蔗糖分显著高于R2。随施氮量增加,R1的产糖量呈先增加后无显著变化的趋势,R2的产糖量呈先增加后减少的趋势。N375和N450下,R1的产糖量显著高于R2,R1N375和R1N450处理甘蔗含糖量较高,分别为14.95和14.58 t/hm2。（3）R1和R2的当季氮肥利用率分别为22%~36%和20%~32%。因此,当施氮量为375 kg/hm2,以30%基肥、30%分蘖肥和40%攻茎肥是蔗叶还田下宿根蔗的最优施氮模式。 相似文献
6.
Jeffrey W. White Bruce A. KimballGerard W. Wall Michael J. OttmanL.A. Hunt 《Field Crops Research》2011,124(2):213-222
Reliable prediction of the potential impacts of global warming on agriculture requires accurate data on crop responses to elevated temperatures. Controlled environments can precisely regulate temperature but may impose unrealistic radiation, photoperiod and humidity regimes. Infrared warming with automatic control of temperature rise has shown potential for warming field plots above ambient temperatures, while avoiding such biases. In a field experiment conducted at Maricopa, AZ, we assessed the utility of a temperature free-air controlled enhancement (T-FACE) approach by comparing phenology of wheat from a series of six sowing date treatments using T-FACE and an additional nine sowing dates that exposed crops to an exceptionally wide range of air temperatures (<0 °C to >40 °C). The T-FACE treatments were intended to achieve a warming of +1.5 °C during the daytime and +3.0 °C at night; the achieved warming averaged +1.3 °C during daytime and +2.8 °C at night. T-FACE and sowing date treatments had large effects on phenology. A regression-based analysis of simulations with the CSM-CROPSIM-CERES model showed that effects of T-FACE on phenology were similar to what would be expected from equivalent changes in air temperature. However, systematic deviations from the expected 1-to-1 relation suggested that assumed cardinal temperatures for phenology should be revised. Based on the single cultivar and location, it appeared that the base temperature for emergence to anthesis should be reduced from 0 °C to −5 °C, whereas the base temperature for grain filling should be increased from 0 °C to 4 °C and the optimal temperature, from 30 °C to 34 °C. Both T-FACE and extreme sowing date treatments proved valuable for improving understanding of high temperature effects on plant processes, as required for accurate prediction of crop responses to elevated temperatures under climate change. 相似文献
7.
Sunflower simulation using the EPIC and ALMANAC models 总被引：5，自引：0，他引：5
J. R. Kiniry R. Blanchet J. R. Williams V. Texier C. A. Jones M. Cabelguenne 《Field Crops Research》1992,30(3-4):403-423
Modeling of sunflower (Helianthus annuus L.) is challenging because the crop species combines high yield potential with great adaptability. This paper surveys recent modeling-related research on sunflower phenology, growth, and yield. Simulations of sunflower by two closely related models,
and almanac, are described. Phenology was predicted with growing degree days with a 6°C base temperature (GDD6) summed from sowing to maturity, assuming anthesis occurred when 0.62 of the total GDD6 had accumulated. Growth simulation involved leaf area index (LAI) development, light interception and radiation-use efficiency (RUE). Inclusion of a vapor pressure deficit (VPD) effect appeared to make RUE more general. A modified harvest index approach was used to simulate seed yields. The
and
models gave reasonable yield simulations over a wide range of environments and management options. The models should be valuable both for assessing the impacts of different management schemes and for identifying subject areas where additional basic research is needed. 相似文献
8.
9.
以盐城市主推品种扬麦23作为研究对象,设置5个播期(10月31日、11月5日、11月10日、11月15日、11月20日),播期推迟1 d播种量增加0.5 kg/667 m2,比较扬麦23不同播期播量的生育期和部分农艺性状。结果表明:随着播期推迟,播种到出苗时间加长,最短7 d,最长19 d,播期对最终成熟期影响不大,10月31日、11月20日2个播期最终成熟期相差3 d左右;随着播期推迟,株高、有效穗数、穗粒数、千粒质量、最终产量等主要农艺性状均呈下降趋势,其中11月10日与11月15日2个播期最终产量由488.7 kg/667 m2极显著下降至455.4 kg/667 m2。生产上扬麦23在盐城地区适宜在10月31日—11月10日完成播种,宜控制基本苗在18万~20万株/667 m2。 相似文献
10.
11.
为对不同播期和耕作条件下旱地春小麦生育期进行准确预测,利用甘肃省定西市安定区凤翔镇安家沟村2015-2016年大田试验数据及研究区1971-2017年气象数据,通过穷举试错法校准APSIM模型的相关参数,再用相关性分析检验,进而基于模型模拟数据分析播期和耕作措施对旱地春小麦生育期的影响。结果表明,春小麦全生育期及各生育阶段持续天数模拟值与实测值相关系数大于0.9,均方根误差（RMSE）为0.7～3.0 d,归一化均方根误差（NRMSE）为2.34%～6.93%,说明APSIM模型精度较高。随着播期的推迟,春小麦从种子萌发阶段到器官建成阶段（播种-开花）持续天数明显减少,籽粒形成阶段（开花-成熟）播期对持续天数影响不大。不同播期下,耕作措施对春小麦生长阶段持续天数影响都不显著。 相似文献
12.
Results are reported from on-farm surveys of N2 fixation in Nepal, conducted between 1994 and 1999, involving the summer legumes soybean, mashbean and groundnut, and the winter legumes lentil and chickpea, at various locations in the Hill and Terai regions of Nepal. Additional less-detailed data were also collected for pigeonpea, grasspea and fababean. There were a total of 107 crops in the major and minor surveys. Estimates of the proportion of legume nitrogen (N) derived from N2 fixation (Pfix) were determined using the natural 15N abundance method. Mean estimates of Pfix for the various species were 62% (soybean), 47% (mashbean), 57% (groundnut), 78% (lentil), 79% (chickpea), 75% (pigeonpea), 87% (grasspea) and 85% (fababean). Estimates of total N fixed (including roots) were 59 kg N ha−1 (soybean), 28 kg N ha−1 (mashbean), 153 kg N ha−1 (groundnut), 72 kg N ha−1 (lentil), 84 kg N ha−1 (chickpea), 412 N ha−1 (pigeonpea) and 80 N ha−1 (grasspea and fababean). The on-farm measurements of N2 fixation were generally similar to those of experimental crops in the same areas of the country. Correlation matrices of soil fertility parameters, shoot dry matter and N, and N2 fixation revealed that the total amounts of N fixed were influenced primarily by crop growth. Based on the above figures, it was estimated that approximately 30,000 t N were fixed annually in Nepal by legumes, valued at US$ 15 million. 相似文献
13.
14.
T.D. Setiyono K.G. Cassman J.E. Specht A. Dobermann A. Weiss H. Yang S.P. Conley A.P. Robinson P. Pedersen J.L. De Bruin 《Field Crops Research》2010
SoySim is a new soybean (Glycine max, L. Merr) simulation model that combines existing approaches for the simulation of photosynthesis, biomass accumulation and partitioning with several new components: (i) flowering based on floral induction and post-induction processes, (ii) leaf area index based on logistic expansion and senescence functions, (iii) integration of canopy photosynthesis using a beta function, and (iv) yield simulation based on assimilate supply and seed number. Simulation of above ground dry matter (ADM) and seed yield by SoySim were validated against data from field studies at Lincoln (NE), Mead (NE), Whiting (IA), and West Lafayette (IN) that included 147 site-year-cultivar-planting date-plant-plant population combinations. In each of the four field studies, agronomic management other than planting date and plant population was optimized to achieve growth with minimal limitation from pests, nutrients, or other controllable factors. SoySim requires just two genotype-specific and two crop management-specific input parameters and yet provides reasonable accuracy in simulating growth and yield under optimum growth conditions across a wide range of sowing dates, plant population, and yield (2.5–6.4 Mg ha−1) in the North-Central U.S. Corn Belt. Simulated seed yield had a RMSE of 0.46 Mg ha−1. Few cultivar-specific parameter input requirements, lack of requirements for specification of key developmental stages, and mechanistic treatment of phenological development, canopy photosynthesis, and seed dry matter accumulation give several advantages to SoySim for use in research and for use as a decision-support tool to evaluate the impact of crop management options on yield potential in favorable environments. 相似文献
15.
Lianxin Yang Jianye Huang Hongjie Yang Guichun Dong Hongjiang Liu Gang Liu Jianguo Zhu Yulong Wang 《Field Crops Research》2007,100(2-3):189-199
Over time, the relative effect of elevated [CO2] on the photosynthesis and dry matter (DM) production of rice crops is likely to be changed with increasing duration of CO2 exposure, but the resultant [CO2] effects on rice N concentration, uptake, efficiency and allocation remain unclear, especially under different soil N availability. Therefore, we conducted a free-air CO2 enrichment (FACE) experiment at Wuxi, Jiangsu, China, in 2001–2003. A japonica cultivar with large panicle was grown at ambient or elevated (ca. 200 μmol mol−1 above ambient) [CO2] under three levels of N: low (LN, 15 g N m2), medium (MN, 25 g N m2) and high N (HN, 35 g N m2 (2002, 2003)). The MN level was similar to that recommended to local farmers. Averaged across all N levels and years, shoot N concentration (dry base) was lower under FACE by 1.8%, 6.1%, 12.2%, 14.3%, 12.1%, and 6.9% at early-tillering, mid-tillering, panicle initiation (PI), booting, heading and grain maturity, respectively. Shoot N uptake under FACE was enhanced by 46%, 38%, 6% and 16% on average during the growth periods from transplanting to early-tillering (period 1), early-tillering to mid-tillering (period 2), mid-tillering to PI (period 3) and heading to grain maturity (period 5), respectively, but slightly decreased by 2% in the period from PI to heading (period 4). Seasonal changes in crop response to FACE in ratio of shoot N uptake during a given growth period to that over the whole season followed a similar pattern to that of shoot N uptake, with average responses of 33%, 26%, −3%, −11% and 10% in periods 1–5 of the growth period, respectively. As a result, FACE increased final aboveground N uptake by 9% at maturity. FACE greatly reduced the ratio of leaf to shoot N content over the season, while allocation of N to stems and spikes showed an opposite trend. FACE treatment resulted in the significant increase in N use efficiency for biomass (NUEp) over the season except at early-tillering and in N use efficiency for grain yield (NUEg) at grain maturity. These results indicate that, in order to maximize grain output in a future high [CO2] environment, the recommended rates, proportion and timing across the season of N application should be altered, in order to take full advantage of strong N uptake capacity during the early growth period and facilitate N uptake after that. 相似文献
16.
在热区鲜食玉米的种植研究中,针对不同复种季节筛选适应性品种的研究还较少,为满足鲜食玉米多样化的生产需求,在云南热区德宏州芒市进行甜玉米夏秋两熟复种试验,选用当地主栽甜玉米品种‘库普拉’（T1）、‘金中玉’（T2）、‘高原王子’（T3）、‘瑞佳甜1号’（T4）,分析比较各品种两季种植的差异。试验结果表明：两季各品种农艺性状指标差异均达极显著（P<0.01）,T2、T4株高、茎粗均高于T1、T3,秋播平均茎粗、叶面积指数较夏播分别增长8.78%、16.67%,夏播T2叶面积指数较T1增长94.73%,秋播T4较T1株高增长71.76%;两季各品种饲用品质指标差异均达极显著（P<0.01）,T2、T4的综合饲用品质较好,T2夏播粗蛋白（CP）、粗脂肪（EE）含量分别增长5.52%、8.93%,酸性洗涤纤维（ADF）含量有效降低5.21%,秋播T4较T1粗灰分含量降低40.83%;两季各品种产量产值差异均达极显著（P<0.01）,T1、T3产量产值两季均低于T2、T4,秋播平均产量较夏播增长24.68%,平均总收益增加57.83%（约3.32万元/hm2）,其中T2夏播T4秋播可实现全年果穗总产47.2 t/hm2,茎叶总产42.4 t/hm2,总产值11.35万元。综合季节性及品种表现的差异性,T2更适合夏播,T1、T3、T4更适合秋播,其中秋播的3个品种综合表现好,依次为T4>T3>T1,T2夏播、T4秋播搭配种植可实现效益最大化。 相似文献
17.
栽培措施对高油大豆产量及品质性状的影响 总被引：7，自引：1，他引：6
采用4因素4水平正交试验,研究了高油大豆品种、密度、施肥水平、播期对产量和品质的影响。结果表明,高油大豆的脂肪、蛋白质及蛋脂总量主要受品种自身的遗传因素影响,其次是播期的影响;而施肥水平对高油大豆的产量影响较大;17种氨基酸中,除丝氨酸、胱氨酸和蛋氨酸含量受品种因素影响较大外,其它14种氨基酸及氨基酸总量均受播期因素影响较大,而各种脂肪酸含量主要是由品种自身的遗传因素控制的。 相似文献
18.
盐碱胁迫伴随作物生长各个阶段,筛选获得全生育期耐盐碱大豆资源意义重大。试验通过测定大庆地区盐碱土含盐碱种类、含盐量及pH值等指标,确定筛选用盐碱种类、浓度。在培养皿、发芽袋和盆栽试验筛选中,通过大豆芽期发芽率、芽苗期物质生长量、成熟期物质生长量鉴定耐盐碱大豆种质。结果显示大庆地区盐碱土壤为硫酸盐苏打盐碱土,确定盐碱溶液为NaCl、Na2CO3、NaHCO3和Na2SO4（摩尔比为1∶1∶9∶9）的混合盐碱溶液,以Na离子含量计算总盐浓度为80 mmol·L-1,溶液pH值为8.9,盆栽筛选用土壤盐含量为3.3‰,pH值为8.9。鉴定的887份种质资源中种皮颜色有黑、褐、红、绿、黄及双色等,相关性分析发现大豆耐盐碱性与大豆种皮颜色极显著正相关。通过芽期耐盐碱鉴定,887份大豆资源中筛选获得296份耐以上资源,进一步芽苗期筛选有123份显示高耐,再经过全生育期筛选获得7份高耐资源,5份来源于南方,2份来源于黄淮,62份耐资源,盆栽筛选比例为56.10%。本研究建立了从芽期、芽苗期到全生育期的逐级筛选方法,从887份大豆种质资源中筛选获得69份耐盐碱资源,为耐盐碱育种与耐盐碱基因资源利用提供基础材料。 相似文献
19.
High perennial ryegrass seeding rates reduce plant size and survival during the first year after sowing: does this have implications for pasture sward persistence? 
下载免费PDF全文
下载免费PDF全文 J. M. Lee E. R. Thom K. Wynn D. Waugh L. Rossi D. F. Chapman 《Grass and Forage Science》2017,72(3):382-400
Failure of perennial ryegrass swards to persist is a key issue on dairy farms in many areas of the world. This study describes an experiment conducted to test the hypothesis that high ryegrass seeding rates (>18 kg seed ha?1) reduce plant size and physical survival during the first year after sowing, with negative implications for population persistence. Four cultivars representing four functional types of perennial ryegrass were sown at five seeding rates (equivalent to 6, 12, 18, 24 and 30 kg seed ha?1) with white clover in three dairying regions of New Zealand. Plant establishment rates, size and survival were measured for the first 13 months after sowing. Herbage accumulation, botanical composition and perennial ryegrass tiller density were also monitored. Increasing seeding rate reduced plant survival in the seven weeks after sowing, reflecting likely differences in germination and very early mortality of small seedlings. Thereafter, plant survival was relatively high and consistent across seeding rates at two sites but was consistently greater in the 6 kg ha?1 treatment compared with the 24 and 30 kg ha?1 treatments at one site. Higher seeding rates also increased ryegrass tiller density and the contribution of ryegrass towards total herbage biomass but reduced the contribution of white clover. Very few cultivar × seeding rate interactions were detected for any of the measured variables. Many of the seeding rate effects dissipated by the end of the first year after sowing, indicating that high seeding rates did not predispose swards to poor persistence in the longer term, irrespective of ryegrass functional type. 相似文献
20.
The effect of maturity at harvest of whole-crop barley for ensiling on intake and liveweight gain of dairy steers differing in initial live weight (LW) was evaluated in an experiment over two years. Light (104–120 kg) and heavy (402–419 kg) dairy steers were fed diets containing predominantly whole-crop barley silage harvested at the milk stage [dry matter (DM) content of 284 g kg−1 and neutral-detergent fibre (NDF) concentration of 526 g kg−1 DM] or the dough stage of maturity (DM content of 328 g kg−1 and NDF concentration of 445 g kg−1 DM) and supplemented with up to 1 kg of concentrate. Dry matter intake (g kg−1 LW) was higher for whole-crop barley harvested at the dough stage than at the milk stage of maturity and the difference was greater in heavy than in light steers ( P < 0·001). Liveweight gain was higher and feed conversion ratio was lower for dough-stage compared with milk-stage silage ( P < 0·05) but there was no interaction with size of steer. Whole-crop barley harvested at the dough stage of maturity promoted higher liveweight gains in dairy steers compared with whole-crop barley harvested at the milk stage due to a higher DM intake. 相似文献