长期秸秆覆盖条件下施氮对冬小麦生长的影响

通过9年定位试验,研究了秸秆覆盖(不覆盖和秸秆覆盖4 500 kg·hm~(-2))和施氮量(0、75、150、225、300 kg·hm~(-2))对冬小麦群体动态、产量三要素和籽粒产量的影响。结果表明,秸秆覆盖显著降低冬小麦越冬期分蘖数和春季总茎数,越冬期分蘖数最多降低24%,春季总茎数最大降幅为40.7%;秸秆覆盖导致单位面积穗数减少,平均降幅5.6%,但穗粒数有增加趋势,对千粒重无显著影响;与无覆盖相比,秸秆覆盖的冬小麦籽粒产量略有降低。无论秸秆覆盖与否,小麦越冬期分蘖数、春季总茎数以及单位面积穗数均与施氮量呈抛物线的关系,穗粒数随施氮量的增加而增加,千粒重则随施氮量增加而降低;施用氮肥使小麦籽粒产量最高增幅接近70%;在供试条件下,秸秆覆盖无增产效应。相比秸秆覆盖,同样小麦产量水平下,常规栽培需氮肥较少。     

控制灌溉条件下种植密度对玉米中地77生长和耗水的影响

以玉米中地77为材料,研究了辽西半干旱区控制灌溉条件下种植密度对玉米生长和耗水的影响.结果表明,随着玉米的生长,株高、茎粗、单株叶面积、穗长、轴重、行粒数、穗粒数和穗粒重随种植密度的增加有减小的趋势,穗粗和穗行数受种植密度的影响较小,但叶面积指数、秃尖、日耗水量、阶段耗水量和全生育期耗水量均随着种植密度的增加而增大,全生育期高密度玉米总耗水量高出低密度28.6％;回归分析表明玉米产量和水分利用效率均随种植密度的增加先增大后减小,综合考虑节水和增粮的目的,在辽西半干旱地区控制灌溉条件下,建议玉米中地77种植密度为6 ～ 6.75万株·hm-2.     

粳稻品种抗稻瘟病性与其生物学性状的相关关系研究

对３４２份粳稻材料进行抗稻瘟病性（抗叶瘟、穗颈瘟）与其生物学性状（株高、穗长、每穗粒数、分蘖率、单株有效分蘖数、空秕率、着粒密度，以及成熟期等）相关关系研究，结果不同品种（系）间存在着一定差异。抗叶瘟性与株高、穗长、每穗粒数、单株有效分蘖数、着粒密度呈显著正相关，相关系数依次为：０．４０９、０．４９１、０．４２６、０．６５７、０．４７１；与空秕率呈显著负相关，相关系数为－０．５９１。抗穗颈瘟性与株高、每穗粒数、单株有效分蘖数呈显著正相关，相关系数分别为：０．７１７、０．４６２、０．３６２；与空秕率、分蘖率、着粒密度呈显著负相关，相关系数依次为：－０．３４３、－０．３３２、－０．４７６。试验表明，株高、单株有效分蘖率、每穗粒数、空秕率等性状，可做为主要标记，在粳稻品种（系）抗稻瘟病性选鉴上应用     

施肥对丘陵旱地冬小麦生长发育和水分利用的影响

在豫西黄土丘陵区两年的田间试验表明：（１）施氮和施磷均可显著提高小麦的生物产量、籽粒产量、株高,穗长,单株干重、穗粒数和穗粒重、施磷还可显著提高单株成穗数、单株粒数和单株粒重;施氮显著降低小麦的经济系数。（２）施肥可改善小麦的单株性状发育,耗水增加,但氮肥肥效主要表现在拔节以前,而磷肥肥效主要表现在拔节以后。（３）施肥对麦田土壤水分动态变化的影响较小,但可显著提高小麦的产量和ＷＵＥ;灌浆期干旱是导     

渭北旱地小麦品种演变及遗传参数估算研究简报

通过对陕西省东渭北旱地小麦品种演变的分析，表明株高呈降低趋势，单株产量、千粒重、蛋白质含量均表现增加趋势，分蘖习性亦表现增加趋势；遗传参数估算结果表明，穗粒数、千粒重、结实小穗、穗长的广义遗传力较高，但适宜渭北旱地种植推广的高产抗旱兼用品种资源亟待充实和提高。     

渗灌条件下覆盖对旱区冬小麦增产效应研究

3年研究表明：与传统的露地条播种植方式相比，旱区冬小麦地下渗灌与膜上穴播栽培技术体系相结合，有更好地发挥水增产效应，提高水分利用率，小麦植株发育健壮，干物质积累增多，分蘖成穗增加，群体光合能力增强；更为显著的是，在产量三因素中，每公顷成穗增加了93.0万，穗粒数平均增加1.8粒，千粒重提高了2.1g，每公顷增产2127.0kg，增产率为47.58%，净增产值1265.1元。     

冬小麦田大穗看麦娘种群动态及对小麦产量的影响

为明确麦田杂草大穗看麦娘Alopecurus myosuroides的田间种群发生动态规律,采用固定样方和随机样方取样方法于2013—2015年在山东省济南市研究了冬小麦田大穗看麦娘田间种群的萌发和生长动态,并分析了不同密度大穗看麦娘对小麦产量及其构成因素的影响。结果表明:在济南市小麦播后20~40 d为大穗看麦娘出苗高峰期,至11月下旬出苗量占全年出苗总量的97.1%。11月上旬,大穗看麦娘开始出现分蘖,至翌年4月上中旬结束,分蘖数平均每株为6.3个,比小麦多3.1个。3月下旬大穗看麦娘开始拔节,4月中旬平均株高超过小麦,5月下旬平均株高达到75.6 cm,高出小麦2.5 cm。5月上旬大穗看麦娘单茎平均鲜重达到最大为1.7 g,小麦为12.6 g。大穗看麦娘出苗、株高、分蘖和鲜重的变化与小麦变化趋势一致,与时间、温度密切相关。随着大穗看麦娘密度的增加,小麦产量急剧下降,当密度达到420株/m~2时,小麦产量损失率高达65.8%。大穗看麦娘对小麦产量构成因素中的穗密度影响最大,其次是穗粒数,对千粒重影响不显著,当密度为420株/m~2时,小麦穗密度减少55.2%,穗粒数减少26.4%。     

全膜双垄沟播玉米田选用除草地膜的适宜田间杂草密度研究

在陇东旱塬生态条件下,田间测定了全膜双垄沟播玉米田选用化学除草地膜和黑色地膜的适宜田间杂草密度。结果表明,全膜双垄沟播玉米田覆盖白色地膜,玉米主要农艺性状、产量及经济效益均随田间杂草密度的增加而降低。杂草密度至少达到116.68株/m2和163.48株/m2时,分别选择覆盖化学除草地膜和黑色地膜可使玉米株高、株高整齐度、茎粗、茎粗整齐度、果穗长、果穗粗、穗粒数、百粒重、有效成穗株率、单位面积有效果穗数等主要农艺性状较覆盖白色地膜有明显改善,玉米产量和经济效益较覆盖白色地膜均有显著提高,产量增幅分别达到1.89%~48.18%和3.87%~47.72%,纯收益增幅分别达到4.49%~157.16%和11.21%~158.88%。     

西宁旱地地膜覆盖冬小麦试验初探

在旱地以“阿勃”品种为材料研究了秋播后覆膜与露地秋播、春播等处理下小麦的生育期、分蘖成穗数、穗部性状及产量表现。结果表明：地膜覆盖可保护麦苗安全越冬，保持土壤水分，延长小麦苗期生长期，增加分蘖成穗数，与春播相比，增产效果显著，并能提前7－13d收获。     

种植密度对糜子生长发育及产量影响

采用完全随机区组试验设计,以河曲大红黍为材料,设定6个密度处理,研究不同种植密度对糜子的株高、茎粗、分蘖数等形态指标,单株叶面积、叶绿素相对值、光合速率等光合指标,干物质积累量,产量构成因素及产量的影响;运用非线性回归分析的方法,对密度与作物产量的经验模型进行模拟.结果表明:种植密度超过一定范围值时,随着密度的增加,株高增大,茎粗变细,分蘖数减少和光合生理指标均降低,穗重、穗粒重和有效穗粒数逐渐减少,干物质积累量减少,产量降低;产量随着种植密度增加呈先升后降的趋势,二次曲线模型的方程式为Y=176.78471+ 11.51879X-1.29607X2,理论最适密度范围为4万株/666.7m2-5万株/666.7m2.     

反枝苋对烤烟农艺性状及产值的影响

为了明确烟田主要杂草反枝苋对贵州烤烟农艺性状、产量、产值的影响,反枝苋按0~25株/m~2的密度栽种,共设置13个处理,在烤烟成熟期记录株高、茎粗、叶片数、叶长、叶宽、叶鲜质量、地上植株鲜质量、茎秆鲜质量、叶干质量、产值等一系列指标参数,通过11种曲线方程进行拟合、回归分析。结果发现三次方程(y=b_0+b_1×x+b_2×x~2+b_3×x~3)具有最高的拟合度和实用性,建议生产上可以用该三次方程预测反枝苋对烟草农艺性状、产量、产值的影响。     

天山北坡4种栽培杨树的功能性状分析

植物功能性状可以用来推断植物生活史策略,反映生态系统功能。为了研究天山北坡4种栽培杨树适应环境的生态策略差异,对其主要功能性状进行比较分析。结果表明,4种杨树的叶片大小、叶片厚度、叶干物质含量、茎皮厚度、木材密度和根、茎、叶全N,P,K含量均差异显著;但4种杨树间比叶面积差异不显著;新疆杨单叶面积和干物质量最大,胡杨叶片厚度和木材密度最大,钻天杨茎皮厚度最大;4种杨树的叶片N含量均显著高于茎和根,茎和根的N和P含量差异均不显著,除胡杨外,其他3种杨树叶片P含量均显著高于茎和根,K含量在4种杨树的根、茎、叶器官中表现不一致;钻天杨根、茎、叶的N,P,K养分含量都相对较高,俄罗斯杨的根、茎、叶的N,P,K养分含量都相对较低。4种杨树功能性状不同反映了植物对环境的适应性差异。     

Effect of Tillage Implements and Weed Management Techniques On Nutritive Values of Wheat Grains

Field experiments were conducted on wheat during 2017–2018 and 2018–2019 under rainfed conditions. The statistical significance between treatment means was determined at 5% significance level. Data were recorded on weed density, protein, fat and ash contents of wheat grains. Weed density in shallow tillage was highest (20.67?m^?2) while it was lowest (14.23?m^?2) in deep tillage. In weed control factor, weed density was highest in weedy check (33.10?m^?2), followed by parthenium aqueous extract (21.50?m^?2), and lowest (6.79?m^?2) in plots treated with Affinity (isoproturon?+?carfentrazone). Results showed that the highest crude protein content (10.88%) was recorded in deep tillage, while lowest (10.45%) in shallow tillage, indicating that tillage depths have an impact on wheat grains protein content. For weed control factor, the crude protein content was highest (11.98%) in Affinity treated plots, followed by herbicides, Buctril super (bromoxynil?+?MCPA) (11.44%) and Puma super (fenoxaprop-p-ethyl) (11.12%). Hence, the control measures also affected crude protein content of wheat grains, which is also obvious from the weedy check where wheat grains crude protein content was lowest (9.73%). The two years combined data analysis also showed the highest crude fat content (1.75%) in deep tillage treatments followed by normal tillage (1.67%) and lowest fat content (1.53%) in shallow tillage. For ash content, the highest content (3.03%) was with Affinity herbicide treatments, followed by Buctril super (2.74%) and Puma super (2.48%) herbicides. In conclusion, both the tillage and herbicides indicated positive effects on the nutritive status of wheat grains.

     

The effect of leaf rust (Puccinia hordei) on yield response in barley (Hordeum vulgare L.) crops with different yield potentials

The effect of leaf rust was investigated on field-grown crops, in two consecutive seasons, each at a single location, using a non-replicated design. The experiments involved three crops and 10 distinct epidemics in the 1987/8 season, and four crops with seven epidemics in the 1988/9 season. The epidemics were concurrent in each season in subplots within each crop, and the yield range was from 2.2–9.0 t ha⁻¹ in nil-diseased plots. Variation in the experiments, assessed as the percentage coefficient of variation, was in the same range as similar, but replicated, experiments with fewer treatment combinations. Early sowing and high agronomic inputs were associated with greater leaf areas, green area durations and yields than in comparable crops sown later or with lower inputs. Disease intensity was described both by per cent disease severity and by the effect on green area. Disease reduced yield mostly via reduced number of fertile ears (mean 31% for all crops) and grain weight (21% mean reduction). Reductions in these components were greater in the 1987/8 season than in the 1988/9 season, but there was no consistent effect associated with yield potential. The number of grains per ear was affected much less (2.5% mean for all crops) than the other components. There was little evidence for compensation between yield components.     

不同氮水平下冬小麦农学参数与光谱植被指数的相关性

利用光谱仪通过大田试验测量不同氮素水平及不同生育期冬小麦冠层的光谱反射率,测算叶面积指数(LAI)、叶绿素含量(CHL)、叶绿素密度(CHL.D)、地上鲜生物量和地上干生物量等农学参数;在此基础上分析了不同氮素水平冬小麦生育期内的光谱植被指数的变化,并分析了农学参数与植被指数之间的相关性。结果表明:小麦叶面积指数、叶绿素密度与比值植被指数(RVI)和归一化差值植被指数(NDVI)在各生育期呈显著相关,小麦叶片的叶绿素含量与RVI、NDVI在抽穗期呈极显著相关,而地上鲜生物量、地上干生物量与RVI和NDVI从起身到孕穗期呈显著相关。     

Wheat leaf rust severity as affected by plant density and species proportion in simple communities of wheat and wild oats

ABSTRACT While it is generally accepted that dense stands of plants exacerbate epidemics caused by foliar pathogens, there is little experimental evidence to support this view. We grew model plant communities consisting of wheat and wild oats at different densities and proportions and exposed these communities to Puccinia recondita to induce wheat leaf rust. Wild oats was included because it is a common competitor of wheat and may act as a barrier to the dispersal of P. recondita spores among wheat plants. Disease severity was estimated as percentage of wheat flag leaves covered by rust lesions. Seeding density rarely had a significant influence on rust severity, probably because of compensation due to increased tillering at low seeding densities. In contrast, increasing the proportion of wheat in mixtures with wild oats consistently increased wheat leaf rust severity. Regression parameters describing wheat leaf rust severity as a function of wheat seeding density did not differ significantly between pure wheat stands and wheat-wild oat mixtures and, thus, failed to support an effect of wild oats on wheat leaf rust other than through its competitive impact on wheat tiller density.     

北京市湿地入侵植物群落与本地植物群落的生物多样性比较

为明确外来入侵植物对本地湿地植物多样性的影响，在北京市湿地选择23个样地共245个样方进行物种多样性调查，并从不同植物性状数据库获取样方中所有植物的株高、叶长、叶宽、叶面积和比叶面积等10个功能性状数据，对比分析入侵群落与本地群落的物种多样性、系统发育多样性和功能多样性特征。结果显示，在北京市湿地共记录到26种外来入侵草本植物，隶属10科19属，其中，菊科外来入侵植物种类最多，有10种。除比叶面积、叶片碳含量和株高的系统发育信号显著外，其余7种植物功能性状的系统发育信号均不显著，表明大多数功能性状未表现出系统发育保守性。入侵群落所有物种的物种多样性指标Shannon-Wiener多样性指数、物种丰富度指数和Simpson优势度指数以及系统发育多样性指标谱系多样性和平均最近谱系发育距离均显著高于本地群落和入侵群落本地物种，而入侵群落本地物种的功能分散指数和Rao''Q二次熵指数均显著高于本地群落，表明外来物种入侵改变了湿地植物的生物多样性，且外来物种入侵后群落谱系多样性趋于发散，说明与本地植物亲缘关系越远的入侵物种越容易在湿地群落中建立种群，符合达尔文归化假说。     

燕麦孢囊线虫对山东地区小麦产量的影响

为评估燕麦孢囊线虫Heterodera avenae发生对小麦产量损失的影响,采用室内盆栽和田间试验相结合的方法,测定了燕麦孢囊线虫不同初始接种密度下对山东省小麦主栽品种的为害损失。结果表明：盆栽条件下,燕麦孢囊线虫为害小麦,影响小麦农艺性状,每克土壤中初始接种卵量为5~30个时,小麦叶绿素含量、根干重、茎干重、有效分蘖数、穗粒数、千粒重、穗重与未接种线虫处理的小麦相比分别降低了10.89%~34.46%、30.65%~73.95%、13.93%~58.68%、30.48%~53.33%、3.97%~36.93%、-3.73%~1.28%、-0.72%~35.08%;而在田间肥水充足条件下,燕麦孢囊线虫对小麦的各项产量指标无显著影响;繁殖系数与线虫初始密度呈负相关。试验表明,燕麦孢囊线虫发生对小麦产量存在潜在威胁,在制定防治措施时,应充分考虑水肥条件,重视对中低产田的影响。     

野燕麦田间发生密度对小麦、青稞产量损失估测及防除策略的研究

杂草对农作物有很大危害是众所周知的,确切知道不同情况下的草害程度对防治对策有现实的指导意义。目前各地都在进行这方面的试验,方法和准确性也异。本文介绍了野燕麦对小麦、青稞在青海省条件下的危害,其方法可供各地参考。同时对试验中所应用的数理统计是否合宜,也可供讨论。1.田间野燕麦发生密度对小麦、青稞产量损失之间有着极显著的回归关系。野燕麦穗数即花序数每增加1万穗/亩,小麦产量损失5.39斤、穗粒数减少0.15粒、千粒重降低0.102克,青稞产量损失3.5斤、穗粒数减少0.17粒、千粒重降低0.02克。2.小麦三叶期以前田间出苗的野燕麦危害最大,在野燕麦10万株/亩左右密度下,减产35.5%;小麦开始拔节以后出苗的野燕麦危害较小,造成减产8%以下。3.田间野燕麦密度越大,后期复盖阴闭越严重。野燕麦株数每亩16万株以上,复盖度90%以上,并导致小麦倒伏。4.据野燕麦危害损失,结合当前生产水平,对野燕麦发生的轻度危害田、中等危害田、严重危害田、控制田的划分指标和防除策略进行了探讨。     

猪殃殃危害损失及其防除策略初探

猪殃殃是分布很广的一种农田杂草,在江苏严重影响小麦生产。本文论证了此种杂草对小麦生产的影响,讨论了化学防除的适期和指标。