Biomass Yield, Chemical Composition and Potential Ethanol Yields of 8 Cultivars of Napiergrass (<i>Pennisetum purpureum</i>Schumach.) Harvested 3-Monthly in Central Thailand

Eight cultivars of napiergrass (Pennisetum purpureum Schumach.), namely Dwarf, Muaklek, Bana, Taiwan A148, Common, Wruk wona, Tifton and Kampheng San, were grown in central Thailand in 2008-2009 and biomass yield, chemical composition and theoretical ethanol yield were measured. Harvests were made every 3 months. Biomass yield and cell wall compositions differed significantly (P 0.05) among cultivars. Tifton produced the highest annual biomass yield at 58.3 t/ha followed by Wruk wona (52.1 t/ha), while the lowest yield of 27.1 t/ha was in Dwarf. Biomass yield varied with season with highest yields in May and lowest in February during the dry season. Cell wall concentrations were higher in the tall cultivars than in the short ones (Dwarf and Muaklek) (P 0.05). Theoretical ethanol conversion efficiency ranged from 350 to 460 L/t DM among the cultivars following pretreatment with steam explosion. While a number of cultivars showed significant potential for use as biofuels in central Thailand, Tifton seemed to be the most promising.

Effect of Lime and Phosphorus on Yield and Yield Components of Groundnut Varieties [Arachis hypogaea L.] on Acidic Soil in Nedjo District, Western Ethiopia

Groundnut (Arachis hypogaea L.) is an important cash crop for smallholder farmers in western Ethiopia. However, the yield of the crop is very low mainly because of strong soil acidity and poor soil fertility management. A study conducted to evaluate the effect of lime and mineral phosphorus fertilizer on yield components and yield of groundnut. The treatments consisted of three phosphorus rates (0, 46 and 92 kg P2O5·ha-1), three lime rates (0, 6, and 11 ton lime·ha-1), and three groundnut varieties (local cultivar, Werer-961, and Werer-963) was laid-out as a randomized complete design in a factorial arrangement with three replications. The corresponding rates of phosphorus applied per pot of soil (7 kg) amounted to 0, 107 and 215 mg kg·soil-1 and those of lime amounted to 0, 14, and 26 g kg·soil-1. The analysis of variance showed that phenological characters, yield, and yield components significantly affected by interaction of variety, phosphorus, and lime. The highest dry pod yield produced by Werer-963 (2 kg dry pod yield·pot-1) in response to the application 11 t·ha-1 lime and 46 kg P2O5·ha-1. However, Werer-961 produced medium (1.5 kg dry pod yield·pot-1) at 11 t·ha-1 lime and 92 kg P2O5·ha-1 and the local cultivar produced minimum (1 kg dry pod yield·pot-1) at the application of 11 t·ha-1 lime and 92 kg P2O5·ha-1. In terms of phosphorus yield efficiency index, Werer-963 was highly efficient (index of 1.71), and Werer-961 was moderately efficient (index of 0.6). However, the local cultivar was inefficient (index of 0.04). It is at, in acidic soil of the study area Werer-963 is the best to be cultivated with application of lime 11 t·ha-1 and 46 kg P2O5·ha-1 fertilizer, followed by Werer-961. The results of this pot experiment have revealed that farmers in the study area need to switch to cultivating the improved varieties of groundnut rather than local variety with the application of high rates of lime and moderate amounts of phosphorus.

Impacts of ozone on the biomass and yield of rice in open top chambers

The impacts of different O 3 concentration on the biomass and yield of rice were studied by using OTC 1 open top chambers. Experimental treatments included the activated charcoal filtered air (CFA), 50 nl/L (CF50), 100 nl/L (CF100) and 200 nl/L (CF200) concentrations of O 3. The O 3 treatments significantly decreased the total biomass per plant. The elevated O 3 exposure resulted in a more decrease in the root growth than in the shoot growth. Assessments of yield characteristics at the final harvest revealed an O 3 induced decrease in the number of grains per plant, resulting from fewer ears per plant, fewer grains per ear and more unfilled grains per ear. The 1000 grain dry weight and the harvest index (HI) were not changed significantly under 50 nl/L or 100 nl/L O 3 exposure, but reduced by 17.0% and 4.8% by 200nl/L O 3 treatment, respectively. Compared to the CFA treatment, CF50, CF100 and CF200 treatments caused a 8.2%, 26.1%, 49.1% decrease of the grain yield per plant, and a 14 2%, 31 7%, 51 7% decrease of the total biomass per plant, respectively. Linear regression showed that the 7h-daily mean O 3 concentration exposure for 3 months (July September) and AOT40 (cumulative exposure accumulation over threshold 40 nl/L) were well correlated with the relative grain yield. A yield loss of 10% was estimated to be at 46 9 nl/L O 3 for 7h daily mean O 3 concentration exposure or at 12930 nl/(L·h) O 3 for AOT40.

Planting density affected biomass and grain yield of maize for seed production in an arid region of Northwest China

Field experiments were conducted from 2012 to 2015 in an arid region of Northwest China to investigate the effects of planting density on plant growth, yield, and water use efficiency(WUE) of maize for seed production. Five planting densities of 6.75, 8.25, 9.75, 11.25 and 12.75 plants/m^2 were conducted in 2012, and a planting density of 14.25 plants/m^2 was added from 2013 to 2015. Through comparison with the Aqua Crop yield model, a modified model was developed to estimate the biomass accumulation and yield under different planting densities using adjustment coefficient for normalized biomass water productivity and harvest index. It was found that the modified yield model had a better performance and could generate results with higher determination coefficient and lower error. The results indicated that higher planting density increased the leaf area index and biomass accumulation, but decreased the biomass accumulation per plant. The total yield increased rapidly as planting density increased to 11.25 plants/m^2, but only a slight increase was observed when the density was greater than 11.25 plants/m^2. The WUE also reached the maximum when planting density was 11.25 plants/m^2, which was the recommended planting density of maize for seed production in Northwest China.

Yield-density effects on growth and biomass partitioning in Leucaena leucocephala seedlings

Experiments were conducted to study the effects of density on growth and biomass partitioning of Leucaena leucocephala seedlings.Four plantations with densities of 10,000,20,000,40,000,and 80,000 seedlings ha^-1 were evaluated only from 15 to 25 months after planting.At 15 months,crown height and width decreased with increasing density.Seedling height/dbh ratios increased with increasing density.Biomass increased with greater density according to the yield–density effect equation,which was evident for all densities.With increasing age,biomass division to branches and leaves increased,whereas partitioning to roots decreased in the 10,000 and 20,000 seedlings ha-1 plantings.Partitioning to branches and leaves remained relatively steady,while partitioning to roots increased in the 40,000 and 80,000 seedlings ha^-1 plantings.Biomass division into stem and bark components remained relatively steady in all densities.Yield–density and organ yield–density curves shifted upward with increasing seedling age on a log–log graph throughout the experimental period.

覆膜和施化肥对土壤有机碳含量及玉米、大豆产量的影响

以贵州安顺大田试验为依托,设置4个处理:不覆膜不施肥(non-F+CK)、不覆膜施肥(non-F+NP)、覆膜不施肥(F+CK)和覆膜施肥(F+NP),探究覆膜和施肥对土壤有机碳和玉米、大豆产量的影响,为贵州农田土壤固碳培肥和作物产量提升提供理论依据。结果表明:覆膜或施肥对土壤有机碳(SOC)影响不显著;施肥和不施肥条件下覆膜后土壤微生物生物量碳(MBC)含量分别降低了9.1%和10.2%,施肥使土壤MBC显著增加了8.2%~32.5%;施肥对土壤全氮(TN)的增加幅度在2.9%~76.5%之间,施肥和不施肥条件下覆膜处理的TN分别降低了11.4%(P<0.05)和4.4%;与non-F+NP相比,F+NP处理玉米大豆分别增产10.4%和28.6%;SOC与土壤MBC和TN呈正相关,MBC与TN呈显著正相关关系,与C/N呈负相关,玉米和大豆产量均与MBC呈显著正相关。综上,覆膜不利于SOC和MBC含量的增加,施肥则相反,将覆膜与施肥相结合可增加玉米和大豆产量。

大气NH_(3)浓度升高和施氮对冬小麦生物量和氮素利用的影响

为揭示大气NH_(3)浓度升高和施氮对冬小麦生物量和氮素利用的影响,通过开顶式气室,以小偃22为试验材料,于2020-2022两年进行田间微区试验,设置3个施氮水平(0、180和240 kg·hm^(-2))和两种大气NH_(3)浓度(空气背景NH_(3)浓度:0.01~0.03 mg·m^(-3);高NH_(3)浓度:0.30~0.60 mg·m^(-3)),对不同处理下小麦地上部和根系干物质、氮素积累量及氮素利用效率进行分析。结果表明,大气NH_(3)浓度升高能显著提升小麦地上部生物量、根系生物量、地上部氮素积累量和根系氮素积累量,2年内平均增幅分别为5.77%、6.74%、8.94%和9.98%。在空气背景NH_(3)浓度下,施氮后小麦显著增产,180和240 kg·hm^(-2)施氮水平下产量较0 kg·hm^(-2)施氮水平分别提高了45.26%和50.67%。在大气NH_(3)浓度升高环境中,随着施氮量的增加,小麦产量出现先升后降趋势,180 kg·hm^(-2)施氮水平下产量最高,240 kg·hm^(-2)施氮水平下小麦产量较0 kg·hm^(-2)施氮水平降低17.97%,小麦氮肥农学效率和氮素利用率也随之降低。这说明,大气NH3浓度升高的环境中适当减少氮肥施用量能有效提升冬小麦的氮素利用率,稳定小麦产量。

不同钝化剂对镉污染小麦镉富集及产量的影响

为实现河套灌区轻中度Cd污染农田的修复与安全利用,在河套灌区轻中度Cd污染农田开展了为期两年不同钝化剂处理的大田试验,7种钝化剂分别为生物炭(BC)、海泡石(SEP)、膨润土(BE)、坡缕石(PA)、腐植酸(HA)、硅酸钠(SS)、硫酸锰(MN),以不施用钝化剂为对照(CK),分析了不同处理下小麦产量、生物量、各器官Cd富集系数和转运系数,比较了不同钝化剂的钝化效果。结果表明,2020-2021年,SEP和SS处理较CK增产显著,增幅为11.09%~81.49%,各器官生物量均有不同程度的增加,其中籽粒及根增加显著;SS处理显著降低叶部Cd含量,降幅为26.75%,SEP处理显著降低籽粒Cd含量,降幅达47.62%。钝化剂处理下,各部位Cd富集系数均<1,根部到叶部Cd最高。小麦籽粒Cd含量与茎中Cd富集系数呈极显著的正相关,与茎向叶部、根向穗部的Cd转运系数呈显著的正相关;2年茎的Cd富集系数对籽粒Cd富集系数均有显著正效应,穗到籽粒、茎到叶的Cd转运系数对籽粒Cd富集系数影响最大。海泡石和硅酸钠处理增加了小麦产量,降低了植株Cd含量,抑制了Cd在植株体内的转运富集;内蒙古河套灌区轻中度Cd污染农田,推荐施用硅酸钠和海泡石进行小麦安全生产。

带宽和株距对带状间作大豆物质积累分配及产量形成的影响

间套作系统中合理的田间配置能改善作物生长环境,增加系统产量。为进一步完善西南地区大豆-玉米带状间作系统高产高效的田间配置技术,本研究以大豆-玉米带状间作为研究对象,采用二因素裂区试验设计,综合分析2.0 m(B1)和2.4 m(B2)2个带宽与9 cm(P1)、11 cm(P2)、14 cm(P3)、18 cm(P4)4个株距对大豆物质积累分配、籽粒灌浆和产量的影响。结果表明,B2带宽下各株距处理的净光合速率均高于B1,其2年平均值在B2下较B1增加14.26%;相同带宽下净光合速率在B1P4和B2P4达到最大,开花期较B1P1和B2P1增加13.57%和25.21%。2个带宽下大豆群体物质积累均随株距增加呈先增后减的趋势且分别在B1P3和B2P2下达到最大,完熟期B2较B1增加9.82%~22.08%。同时,带宽与株距的增加促进了大豆花后物质的积累与向籽粒的转移,与B1相比,B2处理使大豆花后干物质积累量与干物质转移量分别增加13.82%~28.01%和13.38%~37.76%,籽粒物质积累占比增加到41.80%~44.26%。物质积累的增加改善籽粒灌浆过程,B2带宽下籽粒灌浆活跃期(D)较B1延长2~3 d;2种带宽下平均灌浆速率均在P4达到最大且分别较P1增加5.80%和6.58%。产量结果表明,大豆-玉米带状间作模式中,带宽和株距的增加降低了群体有效株数,增加了单株粒数和百粒重;B2带宽下的大豆产量较B1增加22.32%~36.87%,2个带宽下分别在B1P3和B2P2达到最大值,2年间较B1P1和B2P1增加17.83%~26.44%和10.71%~10.76%。综上所述,2.4m带宽下大豆株距为11 cm时能有效改善大豆花后干物质积累和分配,促进籽粒灌浆,增加单株粒数和百粒重,提高大豆群体产量,实现大豆-玉米带状间作系统的高产高效。

遮荫对盐胁迫下油葵生长和光合生理的影响

盐碱地光伏系统下作物生长受到盐分和遮荫的双重影响,研究双重逆境下作物的生理响应对该系统内作物种植有重要指导意义。本研究以油葵(Helianthus annuus L.)为试验材料,采用盆栽试验,设3个盐分水平(在初始含盐量的基础上外加NaCl含量0 g·kg^(−1)、3 g·kg^(−1)和5 g·kg^(−1))和4个遮荫水平(0%、30%、60%和90%),探究遮荫对盐胁迫下油葵生长、光合特性、叶片解剖结构、生物量积累和分配及籽粒产量等的影响,为盐碱地光伏系统下开展作物种植提供理论依据。结果表明,不同盐分水平下,与不遮荫(遮荫水平0%)处理相比,遮荫会破坏油葵叶片光合反应中心,降低光能转换效率,减小叶片厚度和栅栏组织层,减少光合产物积累,进而抑制茎粗和花盘的生长,影响光合产物分配方向,最终降低籽粒产量;但适度遮荫下油葵会通过增加株高、增大叶面积、提高核酮糖-1,5-二磷酸羧化酶(Rubisco酶)和磷酸烯醇式丙酮酸羧化酶(PEPC酶)活性等方式提高叶片的光捕获能力,促进光合作用进行。不同遮荫水平下,与无盐分处理相比,轻(3 g·kg^(−1)NaCl)、重(5 g·kg^(−1)NaCl)度盐胁迫均会降低油葵的光合效率,抑制株高、茎粗、花盘和叶片的生长,减少光合产物的积累,最终降低籽粒产量,且不同盐胁迫浓度下油葵生长和光合生理特性在不同遮荫水平的变化规律不一致。其中,30%遮荫水平能显著提高轻度盐胁迫下油葵叶片的Rubisco酶和PEPC酶活性,减小叶片厚度,增大栅栏组织层,提高水分利用效率,进而提高油葵光合效率,促进油葵生长。研究表明弱光环境下油葵会通过改变自身形态、光合酶活性、光合产物分配等方式来应对环境胁迫,且遮荫能在一定程度上缓解盐胁迫对油葵造成的负面影响。其中,30%遮荫水平对缓解轻度盐胁迫引起的油葵光合能力降低和生长抑制的效果较好。

混播比例对燕麦与箭筈豌豆生产性能的影响

为筛选适宜禾豆混播比例建立优质人工草地,提高草产品的生物产量与质量,本试验设置5种混播比例开展田间试验,燕麦与箭筈豌豆分别按照1∶0、3∶1、1∶1、1∶3和0∶1混合播种。测定分析了燕麦在开花期、乳熟期和乳熟后期3个生长阶段每个混播比例的干草产量、营养品质、相对密度、土地当量比和种子产量等指标。结果表明,混播比例为1∶1时,箭筈豌豆的株高较高;在燕麦开花期和乳熟期,混播比例为1∶1的干草产量最高;在燕麦乳熟期,燕麦和箭筈豌豆的相对密度都达到最高;随着箭筈豌豆混播比例的增加,干草粗蛋白含量、酸性洗涤纤维含量、相对饲喂价值逐渐增加,粗脂肪含量、中性洗涤纤维含量逐渐降低;在燕麦开花期和乳熟期,混播比例为1∶1的干草粗蛋白产量均最高;随着箭筈豌豆混播比例的提高,土地当量比逐渐增加,总种子产量逐渐降低。综上所述,相比燕麦单播,与箭筈豌豆混播的干草产量和品质上都体现了较大的优势,提高了土地利用效率,1∶1可作为推荐混播比例建植燕麦与箭筈豌豆混播草地。

不同氮磷肥施用量对夏播饲用燕麦生长的影响

为探讨不同氮磷配施肥量对陇东地区饲用燕麦生产性能的影响,选择早熟燕麦品种边锋和中熟燕麦品种梦龙为试验材料,设6个氮磷混合施肥量处理,分别为0(CK)、75、150、225、300、375 kg/hm^(2),研究了不同施肥量处理对2个夏播饲用燕麦农艺性状、草产量及抗寒生理指标的影响。结果表明,不同氮磷施量下饲用燕麦的出苗率、株高、分蘖数、干草产量和抗寒生理指标较对照不施肥均有提高;早熟品种边锋和中熟品种梦龙均以氮磷混合施肥量为300 kg/hm^(2)(N 91.50 kg/hm^(2)+P2O563.00 kg/hm^(2))时效果较好,此时出苗率和分蘖数较多,可溶性糖含量和脯氨酸含量显著增加,草产量达最大值,鲜草产量分别为14356.29、14464.28 kg/hm^(2),较对照不施肥分别增产71.7%、93.5%;干草产量分别为4850.00、4633.33 kg/hm^(2),比对照不施肥分别增产74.3%、82.9%。在陇东地区夏播情况下,氮磷混合不同施肥量对提高燕麦生物量和改善生理指标都有显著作用,早熟品种边锋和中熟品种梦龙均以氮磷混合施肥量为300 kg/hm^(2)(N 91.50 kg/hm^(2)+P2O563.00 kg/hm^(2))时效果最好。因此认为,陇东地区夏播饲用燕麦生产以施N 91.50 kg/hm^(2)、P2O563.00 kg/hm^(2)为最佳氮磷施量。

长期施用有机肥对半干旱区春小麦产量及其水分利用效率和土壤有机碳的影响

以国家土壤质量安定观测试验站黄绵土区的农田长期定位试验为研究对象,研究长期施用有机肥对半干旱区春小麦产量及其水分利用效率和有机碳的影响。结果表明,连续种植7年春小麦,施肥显著影响小麦产量及其水分利用效率,以化肥与有机肥配施(NPKM)处理效果最好,较单施化肥(NPK)、单施有机肥(OM)处理春小麦产量和水分利用效率分别增加了7.18%和7.82%、5.91%和3.83%;在定位施肥初期(前3年),NPKM和NPK处理的效果优于OM,在第4年三者无差异,而第5年及之后,NPKM和OM处理的效果明显好于NPK处理。长期NPKM和OM处理较NPK处理0~20 cm土层土壤有机碳含量分别显著增加了36.88%和31.98%,有机碳储量分别显著增加了31.17%~41.94%和27.80%~35.81%,表层0~10 cm的增加效果显著好于10~20 cm土层。不同施肥处理对0~20 cm土层土壤微生物生物量碳(MBC)的影响表现为NPKM>OM>NPK>CK,且差异显著,长期NPKM和OM处理较NPK处理土壤MBC分别显著增加了46.4%和28.7%,长期单施NPK处理可显著增加土壤MBC含量,但对有机碳影响不明显。综上所述,长期NPKM或OM处理可显著增加黄绵土小麦地土壤有机碳和MBC含量,增加有机碳储量,有利于农田土壤固碳增汇,提高小麦产量及其水分利用效率。

免耕对玉米生产力的影响:基于全球荟萃分析

通过对196篇相关文献的1 043对数据进行全球荟萃分析,评估免耕条件下玉米籽粒产量、秸秆生物量和叶面积指数的变化,并探讨气候、土壤、管理因素对其影响程度和方向。结果表明,相较于传统翻耕,免耕总体上显著降低了玉米籽粒产量、秸秆产量和叶面积指数5.7%、4.1%和9.7%。然而,这种效应因气候、土壤和管理措施而不同。在相对干旱的气候环境(年平均气温为>15℃、年平均降雨<600 mm)和恶劣的土壤条件(土壤体积质量>1.4 g/cm3、土壤有机碳含量<5.8 g/kg、土壤全氮为<0.75 g/kg)下,免耕条件下玉米生产力(籽粒产量和秸秆生物量)水平相对更好。其中,土壤有机碳含量和土壤速效钾含量与玉米籽粒产量呈显著负相关,年平均降雨和土壤速效磷含量与玉米籽粒产量和秸秆生物量呈显著负相关,土壤体积质量与玉米籽粒产量和秸秆生物量呈显著正相关。此外,肥料的高效施用、多样化的种植模式(间作或轮作)、秸秆还田等管理措施能抵消免耕条件下玉米生产力的负效应。总体而言,气候土壤环境相对更恶劣的区域可以从免耕技术上获益更多,而合理的田间管理措施也可以为免耕技术提供更好的生产力效应。

不同栽培基质对螺丝椒生长和产量的影响

为筛选出具有区域特点以及更适合推广的螺丝椒栽培基质,以炉渣、沙子、腐熟玉米秸秆配制成不同的复混基质,在塑料大棚内对螺丝椒进行槽式基质栽培,比较不同栽培基质螺丝椒的株高、生物量、产量以及理化性状,探讨不同栽培基质对螺丝椒生长和产量的影响。结果表明,不同处理组螺丝椒的株高、生物量、产量均表现出一定差异,T_(4)处理组(沙子∶秸秆=3∶2)的株高在12.3~118.6 cm、生物量为91.9 g·株^(-1)、产量为2 418 kg·(666.7 m^(2))^(-1),均为最高。然后依次是T_(5)处理组(菜园土)、T_(3)处理组(炉渣∶秸秆=3∶2)、T_(2)处理组(炉渣∶沙子=3∶2)和T_(1)处理组(炉渣);各处理组基质的理化性质间也表现出一定的差异性,基质的理化性状与螺丝椒的株高、产量均符合y=a+bx(P<0.01)的直线函数关系,R^(2)在0.465 6~0.879 8之间。说明沙子∶秸秆=3∶2的复混基质更适宜螺丝椒的生长,也利于其产量提高。

秸秆覆盖对黑土区土壤微生物量、酶活性及大豆产量的影响

为了探究秸秆覆盖量对黑土区土壤微生物量、酶活性及大豆产量的影响,以垦丰16为试验材料,分别设置无秸秆覆盖(CK)、0.5 kg/m2秸秆还田覆盖(T1)、1.0 kg/m^(2)秸秆还田覆盖(T2)、1.5 kg/m^(2)秸秆还田覆盖(T3)4种处理,测定大豆生育期内耕作层土壤细菌、真菌、放线菌数量以及脲酶、过氧化氢酶活性和大豆产量,对比分析不同秸秆覆盖量对土壤微生物量、酶活性及大豆产量的影响。结果表明,大豆全生育期内土壤细菌数量呈先升高后降低的趋势,其中T2处理细菌总数量最大,分别较T1、T3、CK处理提高33.08%、9.30%、65.38%;真菌数量呈先升高后降低、再升高再降低的趋势,其中T2处理真菌总数量最大;放线菌数量整体上呈先升高后降低的趋势,随着秸秆覆盖量的增加而增加。各处理脲酶活性表现为T1>T2>T3>CK,且秸秆覆盖处理分别较CK处理提高32.64%、29.42%、18.23%;过氧化氢酶活性表现为T2>T3>T1>CK,不同处理酶活性均在开花期达到最高。秸秆覆盖处理大豆产量显著高于CK,秸秆覆盖量对大豆产量的影响并未随着秸秆覆盖量的增加而持续增加,T2处理产量最高。大豆产量与脲酶活性、细菌数量呈极显著正相关关系,与真菌数量呈显著正相关关系;过氧化氢酶活性与脲酶活性、真菌数量呈显著正相关关系。综上,1.0 kg/m2秸秆覆盖是黑土区最优秸秆覆盖量。

Effects of paclobutrazol on biomass production in relation to resistance to lodging and pod shattering in Brassica napus L.

Paclobutrazol was sprayed at 0,150,and 300 mg L^(-1) during the closed canopy stage and the early bud stage with two high-yielding cultivars of rapeseed,Yangguang 2009 and Fengyou 520.The impact of paclobutrazol on the accumulation and distribution of biomass and its relationship with yield,resistance to lodging and pod shattering were determined.All the treatments increased the resistance as well as yield.The maximum yield was obtained when paclobutrazol was applied during the closed canopy stage at 150 mg L^(–1).The plant’s resistance to both lodging and pod shattering was the maximum when paclobutrazol was applied during the early bud stage at 300 mg L^(–1).Paclobutrazol also delayed senescence,with the higher concentration or later spraying leading to more obvious effects;improved the net assimilation rate before the early bud stage;and promoted the relative growth rate of the main growth organ at each stage of growth and maximized the rate and quantities of biomass accumulation.However,at the higher concentration and later spraying,the increments were smaller.The spraying also increased the rates of biomass allocation to roots,leaves,and pods,but the rate of allocation to stems decreased as the plants grew shorter.The higher allocation to roots and the lower allocation to stems favoured resistance to both lodging and pod shattering whereas higher allocation to leaves and pods favoured yield.The higher concentration or late spraying led to excessive biomass being allocated to roots,which decreased leaf biomass during the bud stage,leading to greater resistance but lower yields.

Biomasses in Different Organs of Rice Cultivars Developed During Recent Forty-Seven Years in Jilin Province, China

To understand the changes in yield, harvest index (HI) and biomass of aboveground parts of rice, 33 japonica rice cultivars released from 1958 to 2005 were planted. During the 47 years, the grain yield increased from 9 118.36 to 15 060.1 kg/hm2 and HI from 0.46 to 0.55. In the genetic improvement, the total number of tillers per plant decreased, and the biomass per unit area slightly increased at the harvest stage. The increases of yield and HI resulted from the increased biomasses of effective tillers and single stem, and the increase of biomass per stem was related to the increased biomasses of different organs along with the genetic improvement. The stem and sheath biomass at heading and the leaf biomass at 30 days after heading showed the highest increase, up by 75.17% and 49.94%, respectively. The biomasses of leaf and stem-sheath at 10 days after heading, and biomass per stem at 30 days after heading were obviously correlated with the yield. The results indicate that the genetic improvement has resulted in the increase of yield and HI. This increase is correlated with the decrease of total tiller number per plant, and increase of biomasses of effective tillers and single stem. The leaf biomass after heading and the stem and sheath biomass at 10 days after heading can be used as selection criteria for breeding high yielding rice cultivars.

One-time fertilization at first flowering improves lint yield and dry matter partitioning in late planted short-season cotton

Cotton producers have substantially reduced their inputs(labor,nutrients,and management)mainly by adopting a shortseason cropping management that is characterized by late sowing,high density,and reduced fertilization with one-time application at the first bloom stage without lint yield reduction.However,it has been hypothesized that one-time fertilization at an earlier growth stage could be a more effective and economic management practice.A two-year field experiment was conducted by applying five fertilizer one-time fertilization at 0(FT1),5(FT2),10(FT3),15(FT4),and 20(FT5)days after the first flower appeared in the field and one three-split fertilizer application taken as the conventional control(FT6),making six treatments altogether.Cotton growth period,biomass accumulation,yield,and its formation were quantified.The results showed that the one-time fertilization did not affect the cotton growth progress as compared to FT6,however,the total crop cycles for FT3–FT5 were 3 days shorter.FT1 produced the highest cotton lint yield(1396 kg ha–1),which was similar to the FT6 but higher than the other treatments,and could be attributed to more bolls per unit area and higher lint percentage.Cotton yield was positively correlated with cotton plant biomass accumulated.FT1 had both the highest average(VT)(193.7 kg ha–1 d–1)and the highest maximum(VM)(220.9 kg ha–1 d–1)rates during the fast biomass accumulation period.These results suggest that one-time fertilizer application at the first flower stage might be an adjustment that is more effective than at first bloom,and allowed for easier decision making for application date due to non counting of plants with flowers is needed.

Differential Response of Biomass Production and Nitrogen Uptake of Vegetable Amaranth to Two Types of Poultry Manure from Nigeria and Canada

Amaranthus cruentus is one of the sixty Amaranthus species of world. It is widely grown as a green leafy vegetable and for its grain in many tropical countries of Africa, Central and South American, Canada, Mexico and parts of Asia. Depleted soil fertility under intensive cultivation is a major limitation to production of the vegetable. The study investigated the effects of two types of poultry manure on biomass yield and nutrient uptake of Amaranth cruentus in a greenhouse at the University of Manitoba, Winnipeg, Manitoba, Canada in 2011. The experiment was a 2 × 3 × 3 factorial arranged into a Randomized Completely Block Design and replicated three times. The factors were two soil types, two sources of poultry manure and urea, and N rates at 0, 60 and 120 kg⋅N⋅ha−1. Nitrogen uptake by the plants that treated with poultry manure from Canada (PMC) and Urea was 172.5 vs. 171.4 mg⋅pot−1 and 169.5 vs. 163.7 mg⋅pot−1 respectively which were significantly greater than the poultry manure from Nigeria (PMN), 100.6 mg⋅pot−1 and 110.0 mg⋅pot−1 for Red River and Glenhope soil series, respectively. Nitrogen uptake was similar at the N rates of 60 and 120 kg⋅N⋅ha−1 (140.7 vs. 155.6 mg⋅pot−1) in the Red River soil, while N uptake at 120 kg⋅N⋅ha−1 was greater than at 60 kg⋅N⋅ha−1 in Glenhope soil. Shoot dry matter of the vegetable grown in soils treated with PMC and urea was significantly greater than from PMN in Red River soil (10.1, 9.6 and 6.7 g⋅pot−1) and in Glenhope soil (8.8, 8.1 and 6.4 g⋅pot−1). Phosphorus, K, Ca and Mg uptake at 60 and 120 kg⋅</