不同水肥模式对机插稻产量形成和氮肥吸收利用的影响

为阐明机插稻返青活棵-分蘖期不同水肥管理方式对其产量形成和氮肥吸收利用的影响,并提出机插稻返青活棵-分蘖期适宜的水肥管理模式,于2022年以南粳9108和南粳5718为供试品种,在返青活棵-分蘖期设置不同水肥管理方式(水稻返青活棵期多次水分灌排与分蘖期增施氮肥(T1)、水稻返青活棵期多次水分灌排与分蘖期不增施氮肥(T2)、水稻返青活棵期减少灌水不排水且分蘖期不增施氮肥(T3)),对比分析不同水肥管理方式下水稻产量形成和氮肥吸收利用的差异。结果表明,返青活棵-分蘖期不同水肥管理方式对机插稻产量和氮肥吸收利用影响显著。相较于T2处理,T1和T3处理显著增加了水稻产量和氮素积累量,产量分别提高8.2%~9.5%和13.3%~13.7%,成熟期氮素积累量分别提高7.0%~8.8%和12.8%~15.2%(p<0.05)。相较于T1处理,T3处理水稻拔节期茎蘖数降低11.4%~11.9%,茎蘖成穗率显著提高11.3%~12.4%,拔节期叶面积指数和干生物量分别显著降低8.2%~9.3%和6.3%~8.6%,抽穗期-成熟期光合势和群体生长率无显著差异。在产量及其构成因素方面,T1和T3处理间无显著差异(p>0.05)。在氮素吸收利用方面,T1和T3处理在氮素积累量方面无显著差异,但T3处理氮肥农学利用率和氮肥回收利用率较T1分别显著增加20.1%~22.2%和22.7%~23.0%(p<0.05)。综上所述,在分蘖期不增施氮肥的基础上,通过返青活棵期减少灌水和不排水的方式可以实现机插稻产量和氮肥利用率的同步提升。

考虑空间效应的基坑开挖对邻近管线的影响分析

基坑开挖诱发的周边土体位移将会对邻近管线产生不利影响。考虑基坑开挖的空间效应及管线的空间分布,将邻近管线视为Pasternak地基上的Euler-Bernoulli梁,采用三维影像源法提出了预测基坑开挖引起邻近管线附加水平变形的解析方法,并利用已有案例验证了该方法的合理性。结果表明:(1)管线总的水平变形主要由邻近并平行于管线的围护墙变形诱发产生,两侧的围护墙变形对开挖范围外的管线水平变形有较大影响。(2)针对管线的不同空间分布,通过定义的管线水平变形安全系数可预测基坑开挖对管线水平变形的不利程度,同时通过安全系数等值线得到了基坑开挖对管线水平变形的影响区域。(3)当管线与围护墙距离在0.75H(H为基坑开挖深度)内时,安全系数随着管线埋深的增加先减小后增大,且当管线埋深约为1.0H时管线的安全系数最小;当管线与围护墙距离超过0.75H时,安全系数随管线埋深增加而增大。

Effects of slow or controlled release fertilizer types and fertilization modes on yield and quality of rice

There is limited information about the influence of slow or controlled release fertilizer（S/CRF） on rice yield and quality. In this study, japonica rice cultivar Nanjing 9108 was used to study the effects of three different S/CRFs（polymer-coated urea（PCU）, sulfur-coated urea（SCU）, and urea formaldehyde（UF）） and two fertilization modes（both S/CRF and common urea（CU） as basal fertilizer, S/CRF as basal and CU as tillering fertilizer） on rice yield and quality. CU only was applied separately as control（CK）. Results showed that, rice grain yield, chalky kernel rate, chalky area, overall chalkiness, and the content of gliadin, glutenin, and protein, all showed the trends of UF〉PCU〉SCU within the same fertilization mode, and showed the trends of S/CRF as basal and CU as tillering fertilizer〉both S/CRF and CU as basal fertilizer within the same type of S/CRF. In contrast, the contents of amylose, amylopectin, and starch, as well as taste value, and peak and hot viscosity showed trends of SCU〉PCU〉UF, and the trends of both S/CRF and CU as basal fertilizer〉S/CRF as basal and CU as tillering fertilizer. Among S/CRF treatments and fertilization modes, taste values of cooked rice were positively correlated with amylose, amylopectin, and starch contents, as well as gel consistency, peak viscosity, hot viscosity, and cool viscosity, while negatively correlated with globulin, gliadin, glutenin, and protein contents. The types of S/CRF and fertilization modes are important for improving rice yield and quality. Compared to CK, higher yield and similar quality of rice was achieved with UF as basal and CU as tillering fertilizer, and similar yield with improved appearance and eating and cooking quality of rice was achieved with either both UF and CU as basal fertilizer, or PCU as basal and CU as tillering fertilizer.

“独秆”栽培模式下全程氮肥在分蘖中后期施用对旱直播水稻产量和品质的影响

稻麦两熟地区,旱直播水稻生产受前茬小麦收获、全量麦秸秆还田及耕整地质量不高等因素的影响,常采用迟播期、大播量、高基本苗和主茎成穗为主的“独秆”栽培模式,而配套该模式直播稻优质丰产的氮肥管理技术尚缺乏系统的研究。以优质食味粳稻南粳9108为材料,采用机械旱直播方式,基本苗为380×10^(4) hm^(-2),设置不同叶龄期(六、七、八、九和十叶龄期)氮肥追施处理及氮肥追施用量(纯氮180 kg hm^(-2)和225 kg hm^(-2))处理,以基本苗380×10^(4) hm^(-2)和300×10^(4) hm^(-2)的旱直播精确定量氮肥管理(纯氮270 kg hm^(-2),基肥︰分蘖肥︰穗肥=3.5︰3.5︰3.0)为对照,系统比较研究“独秆”栽培模式下,全程氮肥在分蘖中后期施用对旱直播水稻产量和品质的影响。结果表明,随追施叶龄的延后,水稻产量呈先增后降趋势,八叶期追施氮肥水稻产量显著高于其他处理,且追施量增加,水稻产量进一步提高。与2组对照相比,在纯氮180 kg hm^(-2),氮肥减量33.3%情况下,不施氮素基肥配合八叶期一次性追施氮肥,可显著提高水稻产量5.10%和8.65%;在纯氮225 kg hm^(-2),氮肥减量16.7%情况下,不施氮素基肥配合八叶期及7 d后二次追肥可显著提高水稻产量7.46%和11.09%。不施氮素基肥配合八叶期追施氮肥水稻产量提高的原因是,保障较大穗型的基础上增加有效穗数,显著提高群体颖花量,同时保持较高水平的结实率和千粒重。随追肥叶龄延后,水稻整精米率呈增加趋势,垩白度呈增大趋势,蛋白质含量增加,直链淀粉含量下降,食味值呈降低趋势。与2组对照相比,不施氮素基肥配合八叶期追施氮肥的水稻,加工品质提高,整精米率提高0.67%~2.23%;外观品质变好,垩白度降低3.6%~14.5%;营养品质提升,蛋白质含量增加3.03%~14.08%;蒸煮食味品质呈变优趋势,直链淀粉含量下降4.23%~10.95%;食味值无显著差异。综上所述,“独秆”栽培模式下基肥不施氮肥配合全程氮肥在分蘖中后期适宜叶龄施用可实现稻麦两熟地区旱直播稻迟播期、大播量和高基本苗生产方式的提质增产生产。

甬优系列籼粳杂交稻产量及氮素吸收利用的差异

从24个甬优系列籼粳杂交稻品种(系)中,根据不同产量水平和氮素农学利用率筛选出具有代表性的3种类型(高产氮高效、高产氮中效、中产氮中效),系统比较各类型产量和氮素农学利用率,以探究高产氮高效型籼粳杂交稻产量和氮素吸收利用特征。结果表明,高产氮高效型产量显著高于高产氮中效型和中产氮中效型,分别高4.04%~4.38%和13.37%~13.41%,其高产原因在于群体颖花量大,能达到5.87×10^8~6.20×10^8 hm^-2。与高产氮中效型和中产氮中效型相比,高产氮高效型成穗率高,能保持在68.83%~70.05%;抽穗期叶面积指数高,且生育后期衰减平缓,成熟期叶面积指数在3.85以上;抽穗至成熟期干物质积累量大,达7.91~7.99 t hm^-2,全生育期干物质量可达21.15~21.46 t hm^-2。在氮素吸收利用方面,高产氮高效型总吸氮量显著高于高产氮中效型和中产氮中效型,分别高5.07%~5.14%和4.50%~5.96%;拔节至抽穗期和抽穗至成熟期氮素吸收速率表现为高产氮高效型>高产氮中效型>中产氮中效型,花后茎鞘氮素转运量、穗部氮素积累量和氮素收获指数也有相同表现;氮素回收利用率、农学利用率、生理利用率和偏生产力均以高产氮高效型最高;高产氮中效型除氮素回收利用率和百千克籽粒吸氮量外,其他各项氮素利用指标均高于中产氮中效型。

穗肥氮素用量与结实期遮光复合作用对常规粳稻品质的影响

氮素穗肥用量和结实期遮光可通过影响叶片光合和植株氮营养状况对水稻籽粒碳氮代谢能力产生调节作用,从而形成不同特征的稻米品质。为探明氮素穗肥用量与结实期遮光复合作用对常规粳稻品质的影响,于2019—2020年以生育期相近的常规粳稻淮稻5号、南粳9108和扬农香28为材料,设置40.5 kg hm^(-2)(N1)、81.0 kg hm^(-2)(N2)、121.5 kg hm^(-2)(N3)3个氮素穗肥用量处理,并于抽穗至成熟期采用人工遮阴方式控制水稻冠层光照,包括100%自然光照(S0)和50%自然光照(S50)处理,研究了结实期不同光氮处理组合对稻米品质的影响效应。结果表明:糙米率、精米率、整精米率在S0条件下随氮素穗肥用量的增加呈先升后降趋势,在S50条件下呈下降趋势,其中S0N2处理的整精米率最高,加工品质较好;垩白粒率和垩白度均呈S50N3>S50N2>S50N1>S0N3>S0N2>S0N1的趋势,且穗肥氮素用量的增加和结实期遮光对稻米提高垩白粒率和垩白度具有累加作用。穗肥氮素用量增加和结实期遮光均降低直链淀粉含量和胶稠度,提高蛋白质含量,其中谷蛋白的变异系数高于其他蛋白组分。穗肥氮素用量增加和结实期遮光不利于稻米食味值评分,不同品种的食味特征值对食味值评分的直接影响有差异。水稻淀粉的峰值黏度、崩解值随穗肥氮素用量增加和结实期光照强度下降而降低,消减值则上升,光氮复合作用增加了上述指标的差异。在穗肥氮素用量与结实期遮光复合作用下从直链淀粉含量和蛋白质含量比值趋势性变化来分析,结实期植株碳氮代谢能力强弱发生了变化。直链淀粉含量和蛋白质含量均与稻米食味值评分呈极显著的负相关关系,其中蛋白质的相关系数更大。因此,适量减施氮素穗肥有利于水稻结实期遭遇寡照后的稻米加工品质、外观品质及蒸煮食味品质提升,并且降低直链淀粉含量特别是蛋白质含量可能是提升稻米食味的有效途径,以期为优质水稻丰产调优栽培技术的更新提供依据。

长江中下游地区常规中熟粳稻产量、品质及氮素吸收性状的相互关系分析

于2017—2018年分别收集长江中下游地区90份和105份常规中熟粳稻品种(系)为材料,研究各供试品种(系)的产量、稻米品质以及氮素吸收量,对产量、品质、氮素吸收之间的相互关系进行系统分析,以期探索长江中下游地区常规中熟粳稻产量、品质和氮素吸收协同提升途径。结果表明,产量与千粒重、穗粒数呈极显著正相关,与结实率呈负相关,与有效穗数相关性不显著。穗粒数对产量的直接促进作用最大,而有效穗数通过其他产量构成因素对产量形成的限制作用最大,千粒重通过其他产量构成因素对产量形成的限制作用最小。总吸氮量与茎、叶、穗的干重均呈极显著正相关,与茎、叶、穗含氮率相关性较弱,增加茎、叶、穗的干重是增加氮素吸收量的有效途径。直链淀粉、蛋白质与稻米加工品质、外观品质以及稻米食味均存在显著的相关性,降低直链淀粉和蛋白质含量,有利于提升稻米食味品质,但不利于加工品质和外观品质的改善。影响产量的关键指标千粒重、穗粒数与影响氮素吸收的关键指标茎干重、叶干重、穗干重均呈极显著正相关。直链淀粉与茎干重、叶干重、穗干重、千粒重以及穗粒数无显著相关性,而蛋白质与茎干重、叶干重、穗干重、千粒重、穗粒数总体呈负相关。综上所述,在直链淀粉淀粉含量相对较低的品种中,选择生物量较大,且穗粒数较多、千粒重较高的品种,能够实现长江中下游地区常规中熟粳稻产量、氮素吸收以及食味品质的协同提升,但这可能不利于加工以及外观品质的改善,有待于进一步研究其中的平衡关系。

基于BIM技术的建筑工程构件管理标准研发

随着企业BIM技术的推行以及工程项目的实践,积累的族文件不断增加,对族、构件进行重命名、规范化、整合以及加密共享的需求日益增强。本文简单介绍施工单位企业级构件库管理的应用现状,通过建立构件标准和平台构件入库要求提高集团内族的质量,提升建模效率以及长远的企业族库发展规划。

Increasing the appropriate seedling density for higher yield in dry direct-seeded rice sown by a multifunctional seeder after wheatstraw return

Dry direct-seeded rice(DDR) sown using a multifunctional seeder that performs synchronous rotary tillage and sowing has received increased attention because it is highly efficient,relatively cheap,and environmentally friendly.However,this method of rice production may produce lower yields in a rice–wheat rotation system because of its poor seedling establishment.To address this problem,we performed field experiments to determine the rice yield at five seedling density levels(B1,B2,B3,B4,and B5=100,190,280,370,and 460 seedlings m-2,respectively) and clarify the physiological basis of yield formation.We selected a representative high-quality rice variety and a multifunctional seeder that used in a typical rice–wheat rotation area in 2016 and 2018.The proportion of main stem panicle increased with increasing seedling density.There was a parabolic relationship between yield and seedling density,and the maximum yield(9.34-9.47 t ha-1) was obtained under B3.The maximum yield was associated with a higher total spikelet number m-2 and greater biomass accumulation from heading to maturity.The higher total spikelet number m-2 under B3 was attributed to an increase in panicle number m-2 compared with B1 and B2.Although the panicle numbers also increased under B4 and B5,these increases were insufficient to compensate for the reduced spikelet numbers per panicle.Lower biomass,smaller leaf area,and lower N uptake per plant from the stem elongation stage to the heading stage were partially responsible for the smaller panicle size at higher seedling density levels such as B5.The higher biomass accumulation under B3 was ascribed to the increases in the photosynthetic rate of the top three leaves m-2 of land,crop growth rate,net assimilation rate,and leaf area index.Furthermore,the B3 rice population was marked by a higher grain–leaf ratio,as well as a lower export ratio and transport ratio of biomass per stem-sheath.A quadratic function predicted that 260-290 seedlings m-2 is the optimum seedling density for achieving maximum yield.Together,these results suggested that appropriately increasing the seedling density,and thereby increasing the proportion of panicles formed by the main stem,is an effective approach for obtaining a higher yield in DDR sown using a multifunctional seeder in a rice–wheat rotation system.