Polyamines mediate the effect of post-anthesis soil drying on starch granule size distribution in wheat kernels

Polyamines(PAs) are important endogenous plant growth regulators responding to environmental stress and mediating many physiological processes including grain filling in cereals.This study investigated whether PAs mediate the effect of post-anthesis soil drying on starch granule size distribution,starch content,and weight of superior and inferior kernels of wheat(Triticum aestivum L.).Two wheat cultivars were grown in pots.Three treatments,well-watered(WW),moderate soil drying(MD) and severe soil drying(SD),were imposed from 9 days post-anthesis until maturity.PA levels in kernels and small,medium and large granules were measured.The results showed that superior kernels had much higher free spermidine(Spd) and free spermine(Spm) concentrations,larger volumes of medium starch granules,and smaller-sized large granules than did inferior kernels under all the treatments.Compared to WW,MD significantly increased the concentrations of free Spd and free Spm,activities of soluble starch synthase and granule-bound starch synthase,volume of medium granules,and starch content and kernel weight of inferior kernels,and decreased the size of large granules.SD produced the opposite effect.Application of Spd or Spm to spikes produced effects similar to those of MD,and application of an inhibitor of Spd and Spm synthesis produced effects similar to those of SD.These results suggest that PAs mediate the effect of post-anthesis soil drying on starch biosynthesis in wheat kernels by regulating key enzymes in starch synthesis and that elevated PA levels under MD increase the volume of medium granules and kernel weight of inferior kernels.

Effects of exogenous ABA application on post-anthesis dry matter redistribution and grain starch accumulation of winter wheat with different staygreen characteristics

The objective of this study was to investigate whether and how exogenous abscisic acid(ABA)is involved in mediating starch accumulation in the grain and redistribution of carbohydrates during grain filling of two wheat cultivars with different staygreen characteristics.At blooming stage,plants of Wennong 6(a staygreen cultivar)and Jimai 20(control)were sprayed with10 mg L-1abscisic acid(ABA)for 3 days.The application of ABA significantly(P<0.05)increased grain filling rate,starch accumulation rate and content,remobilization of dry matters to kernels,and 1000-grain weight of the two cultivars.Exogenous ABA markedly(P<0.05)increased grain yield at maturity,and Wennong 6 and Jiami 20 showed 14.14%and 4.86%higher compared yield than the control.Dry matter accumulation after anthesis of Wennong 6 was also significantly(P<0.05)influenced by exogenous ABA,whereas that of Jimai 20 was unchanged.Application of ABA increased endogenous zeatin riboside(ZR)content 7 days after anthesis(DAA),and spraying ABA significantly increased endogenous indole-3-acetic acid(IAA)and ABA contents from 7 to 21 DAA and decreased gibberellin(GA3)content at 14 DAA,but increased GA3content from 21 to 35 DAA.The results suggested that increased yield of staygreen was due to greater starch assimilation owing to a higher filling rate and longer grain-filling duration.

Effects of Soil Moisture on Dynamic Distribution of Dry Matter Between Winter Wheat Root and Shoot

The dynamic relationship of dry matter accumulation and distribution between winter wheat root and shoot was studied under different soil water conditions. The dry matter accumulation in root was greatly influenced by water stress, so as to the final root weight of the treatment with 40% field moisture capacity(FMC) was less than 1/4 of that of the treatment with 80% FMC on average. Water stress during the 3-leaf stage to the tillering stage had the greatest influence on root, and the influence of water stress during the jointing stage to the booting stage on shoot was greater than root. However, water stress during the tillering stage to the booting stage had a balanced effect on root and shoot, and the proportion of dry matter that distributed to root and shoot was almost the same after rewatering. Water recovery during the jointing stage to booting stage could promote R/S, but the increasing degree was related to the duration of water limitation. Soil water condition had the lowest effect on R/S during the flowering stage to the filling stage and the maximal effect on R/S during the jointing stage to the heading stage, R/S of 40% FMC treatment was 20.93 and 126.09% higher than that of 60% FMC and 80% FMC treatments respectively at this period.

Effect of Source-Sink Manipulation on Photosynthetic Characteristics of Flag Leaf and the Remobilization of Dry Mass and Nitrogen in Vegetative Organs of Wheat

The photosynthetic characteristics of flag leaf and the accumulation and remobilization of pre-anthesis dry mass（DM） and nitrogen（N） in vegetable organs in nine wheat cultivars under different source-sink manipulation treatments including defoliation（DF）, spike shading（SS） and half spikelets removal（SR） were investigated. Results showed that the SS treatment increased the photosynthetic rate（Pn） of flag leaf in source limited cultivar, but had no significant effect on sink limited cultivar. The SR treatment decreased the Pn of flag leaf. Grain DM accumulation was limited by source in some cultivars, in other cultivars, it was limited by sink. Grain N accumulation was mainly limited by source supply. The contribution of pre-anthesis dry mass to grain yield from high to low was stem, leaf and chaff, while the contribution of pre-anthesis N to grain N from high to low was leaf, stem and chaff. Cultivars S7221 and TA9818 can increase the contribution of remobilization of DM and N to grain at the maximum ratio under reducing source treatments, which may be the major reason for these cultivars having lower decrease in grain yield and N content under reducing source treatments.

Establishment of ANEDr model for evaluating absorbed-nitrogen effects on wheat dry matter production

Applying mathematic models to evaluate absorbed-N effects on dry matter production at different developmental stages would help determine proper nitrogen management according to crop demands and yield target. Two field trials were carried out for establishing absorbed-N effects on dry matter production（ANEDr） model, using uniform design in 2010–2011and 2012–2013 winter wheat growing seasons in Hebei Province, China. Another field trial was carried out in 2010–2011for model validation. Dry matter and N concentration in leaf and non-leaf organs were measured at setting, jointing, anthesis, and maturity. Theory of best linear unbiased prediction（BLUP） was applied to analyse the N effects of leaf and non-leaf organs on dry matter production. Within ANEDr model, four N-affected phases at each stage were concerned,leaf absorbed-N effect before this stage, non-leaf organ absorbed-N effect before this stage,leaf absorbed-N effect at this stage, and non-leaf organ absorbed-N effect at this stage. In addition, developmental processes, genotype characters and temperature were three factors that determine each N effect. It was demonstrated that ANEDr model can precisely quantify absorbed-N effects on dry matter production with high correlation coefficient（r=0.95）. Comparing with other models, ANEDr model considered both leaf and non-leaf organs according to developmental processes of winter wheat, showed higher flexibility and simplicity, thus could be applied to different environments, cultivars and crops after parameter adjustment.

The Study on Wheat Concurrent-flow Drying Technology

The relation between technology parameters and performance index of the wheat three-stage concurrent-flow drying technology is studied by use of quadratic orthogonial rotate combinative experiment design method.The optimum parameters of drying technology are obtained by nonlinear optimize corresponding regression model and test.All experiment was finished in concurrent-flow grain drying experiment table.The results of this study will be significant for designing energy-saving grain drying machine.

麦穗干插花加工型小麦种质资源的筛选

本研究以麦穗干插花(以下简称麦穗花)加工企业认可的云生1号、云麦53号品种为对照,采用芒长、穗长和茎秆强度3个加工企业认为影响麦穗花加工和销售的重要指标,对42份长芒小麦种质资源进行性状筛选与评价,并利用文献报道的与小麦茎秆强度相关的SSR分子标记对参试资源进行茎秆强度辅助选择,挑选出在农艺性状和分子遗传学上都适合加工麦穗花的优异种质资源,为云南干花产业发展提供新的原材料。结果表明,通过两年的田间种植观测与数据分析,未发现3个性状都较两个对照优异的资源。其中,C6(小黑麦)两年的芒长都较两对照显著优异且穗长和茎秆强度差异不明显或也显著优异,是比两个对照更适合加工麦穗花的优异资源;其次是C3和C9,两年的穗长和茎秆强度都显著优于或与两个对照差异不显著,也是加工麦穗花的较理想资源;C4、C5、C7和C8的穗长较云麦53号显著优异,芒长和茎秆强度则差异不显著或也显著优异。对茎秆强度的SSR分子标记辅助选择结果表明,C4、C6可能携带有与云麦53号相同的BARC59、BARC134和WMC48位点以及与云生1号相同的BARC59位点,C3、C5、C8也可能携带与云麦53号相同的BARC59、BARC134和WMC48位点以及与云生1号相同的BARC59、BARC358位点,C9可能携带有与云麦53号相同的BARC59、BARC134位点以及与云生1号相同的BARC59、WMC48位点。但是,用这些引物获得的分子标记结果与表型评价结果之间的一致性都在50%及以下,可能这些分子标记都不适宜用作供试小麦材料茎秆强度的辅助筛选。今后还需进一步筛选适合评价麦穗花加工型小麦种质资源的指标及分子标记,为选育满足生产需求的优良小麦品种提供技术支持。

陇东旱地冬小麦品种抗旱性鉴定

为研究陇东特殊干旱气候条件下抗旱育种的进展与现状,选取近20 a陇东旱地选育的14个冬小麦新品种(系)为材料,以籽粒产量抗旱指数等为全生育期抗旱性鉴定指标,在旱棚进行全生育期干旱胁迫试验。结果表明,陇育4号和宁麦5号抗旱指数在1.100~1.299范围内,抗旱级别为2级;陇育7号和陇鉴387抗旱指数在0.700~0.899范围内,抗旱级别为4级;其余10个材料抗旱指数在0.900~1.099范围内,抗旱级别为3级。抗旱性级别在2~3级的材料占85.7%。产量性状主因子分析发现,抗旱级别为2级的陇育4号和宁麦5号,在干旱胁迫下有效穗数、穗粒数和千粒重无明显变化;抗旱级别为4级的陇育7号和陇鉴387,在干旱胁迫下有效穗数、穗粒数和千粒重均减幅较大;抗旱级别为3级的其余10个材料在干旱条件下,其产量性状三要素有效穗数、穗粒数、千粒重中只有一项发生变化,没有两项叠加变化。

不同播幅对小麦花后叶片光合特性和产量的影响

为了明确不同播幅对小麦籽粒产量的影响及其形成的生理原因,本研究于2019—2020年和2020—2021年冬小麦生长季,在山东省济宁市兖州区小孟镇史家王子村小麦试验站大田试验条件下设置2种播幅处理:处理1是播幅为8 cm(B1);处理2是播幅为3 cm(B2)。研究了不同播幅对小麦光合特性、冠层光截获特性、干物质积累与转运和籽粒产量的影响。试验结果表明:B1处理开花后叶面积指数和冠层光合有效辐射截获率显著高于B2处理,其冠层光合有效辐射透射率显著低于B2处理;B1处理开花后旗叶叶绿素相对含量、净光合速率、蒸腾速率和气孔导度均显著高于B2处理,其胞间二氧化碳浓度显著低于B2处理;B1处理开花期和成熟期干物质积累量、开花后干物质在籽粒中的分配量、成熟期籽粒干物质积累量均显著高于B2处理;B1处理穗粒数、千粒重均显著高于B2处理;与B2处理相比,B1处理的2年平均籽粒产量和光能利用率分别高6.12%和7.71%。综上所述,播幅为8 cm的B1处理通过塑造了合理的冠层结构,改善了开花后叶片的光合性能,有利于开花后植株的光合物质生产,从而获得了最高的籽粒产量和光能利用率,为本试验条件下的最优处理。研究为小麦宽幅播种节水高产高效栽培技术提供了理论依据。

高水分小麦热风干燥后品质的变化

目的:研究干燥工艺对高水分小麦品质的影响。方法:从外观品质、营养品质、加工品质3个维度探究不同干燥工艺下小麦品质变化规律。选取色泽、湿面筋含量、干燥速率3个指标作为响应值,结合响应面分析方法预测高水分小麦的最佳干燥工艺。结果:干燥温度是主要的影响因素。随着干燥温度的升高,小麦色泽加深,粗蛋白含量和湿面筋含量下降,面团的吸水率、形成时间及稳定时间上升,弱化度下降,粉质指数上升,小麦表皮由凸起的小矩形变为凹陷的小坑状,内部淀粉颗粒由光滑的圆形或椭圆形变为粗糙的不规则状。高水分小麦的最佳干燥工艺条件为干燥温度45℃,风速0.94 m/s,缓苏时间30.4 min,此时色泽L*值为58.811、湿面筋含量为27.292%,干燥速率为8.146×10^(-2)%/min,综合评分为0.613。结论:热风干燥工艺的优化在保证干燥效率的基础上一定程度改善了小麦干燥后的品质。

播种模式对新疆小麦干物质积累和产量及水分利用效率的影响

为确定北疆小麦适宜的播种模式,以北疆主栽冬小麦品种新冬18号和新冬41号及春小麦品种新春44号和新春48号为材料,设置晚播冬小麦(10月8日播种,用B1表示)、极晚播冬小麦和冬播春小麦(10月28日播种,用B2表示)以及春播春小麦(4月4日播种,用B3表示)三种播种模式,比较分析了播种模式间小麦的生育进程、总茎数、叶面积指数、光合势、干物质积累量、经济系数、产量及水分利用效率的差异.结果表明,B2处理的冬小麦较B1处理晚熟约7d,生育期缩短162d,出苗率、最高总茎数、LAI、总光合势、干物质积累量及总耗水量分别降低27.6个百分点、17.1%、11.5%、9.6%、3.7%和15.9%,而水分利用效率提高15.7%,平均经济系数和产量与B1处理无显著差异;B2处理的春小麦较B3处理早熟7d,生育期延长约4 d,出苗率、最高总茎数、LAI和总耗水量分别降低28.1个百分点、7.6%、5.2%和12.3%,总光合势、成熟期干物质积累量、经济系数、水分利用效率和产量分别提高6.3%、4.0%、4.5%、24.0%和8.7%;B2处理下冬小麦较春小麦晚熟约4d,生育期延长约3d,出苗率和最高总茎数的平均值分别降低7.9个百分点和7.6%,产量和水分利用效率均无显著差异.极晚播冬小麦和冬播春小麦的平均产量和水分利用效率均较高,其中产量与晚播冬小麦差异均不显著,熟期接近.综合考虑高产和节水及早熟的需求.本试验条件下,冬小麦极晚播和春小麦冬播是北疆地区小麦的适宜播种模式.

干燥温度对高水分小麦加工和应用品质的影响

为探究不同干燥温度对高水分小麦品质的影响,采用不同热风干燥温度(65、85、105、125℃)对初始水质量分数26%的小麦进行干燥处理,以未烘干小麦为对照,分析干燥对小麦加工及应用品质的影响。结果表明:热风干燥温度对高水分小麦品质影响显著,随热风温度升高,干燥后的小麦容重显著下降,裂纹率显著上升。在相同条件下制得的小麦粉,出粉率和灰分含量变化不大,破损淀粉有所下降,白度上升,粒径减小,溶剂保持力、沉淀指数降低,其中125℃下出粉率影响较大,破损淀粉含量和白度影响较小。与对照样品相比,65、85℃干燥对面筋含量和质量影响不大,面团的加工特性有所改善,馒头比容变化不大,硬度、黏性显著降低。当干燥温度为105℃和125℃时,湿面筋含量、形成时间、稳定时间显著下降,面团的操作性能降低,馒头比容和感官得分下降。对于制作馒头而言,26%水质量分数的小麦可采用不高于85℃的干燥温度。

绿洲灌区绿肥还田对减量灌水小麦产量的补偿机制

探讨绿肥对减量灌水春小麦产量构成及光合产物积累分配特征的响应和机制,可为构建新型小麦节水型种植制度提供实践和理论依据。依托2017年在甘肃河西绿洲灌区开始的小麦复种绿肥田间定位试验,于2021—2022年研究了不同绿肥处理方式下减量灌水小麦的群体生长动态、光合产物累积、转运分配和产量特性。试验采用裂区设计,设420 mm(I3,地方常规灌水量)、370 mm(I2,减量50 mm)和320 mm(I1,减量100 mm)3个灌水水平,绿肥全量翻压还田(WG)、绿肥仅根茬还田(WGR)和不种绿肥(W)3种绿肥处理方式,组成9个处理。结果表明,减量灌水降低了小麦产量和收获指数,绿肥还田可补偿因减量灌水造成的产量负效应。与I3相比,I1处理小麦籽粒产量、生物产量和收获指数分别降低11.5%、3.8%和8.1%,I2籽粒产量降低了3.4%;与W相比,WG籽粒产量、生物产量和收获指数分别提高10.9%、3.7%和8.0%,WGR籽粒产量和收获指数提高了4.8%和3.4%;与WI3相比,WGI2籽粒产量和收获指数分别提高7.2%和5.3%,WGI1和WGRI2的籽粒产量、生物产量和收获指数差异不显著,即麦后复种绿肥并全量还田可补偿减量灌水100 mm产生的产量负效应,可超量补偿在减量灌水50 mm的负效应。绿肥还田补偿减量灌水对小麦产量负效应的主要原因是:(1)绿肥还田提高了小麦生育后期的群体生长率(CGR)和净同化率(NAR),增大了小麦穗数、穗粒数与千粒重。与WI3相比,WGI2拔节至孕穗、孕穗至开花、开花至灌浆期CGR分别提高10.4%、10.5%和7.9%,WGRI2拔节至孕穗、孕穗至灌浆期CGR分别提高6.7%和5.7%,WGI1无显著变化;WGI2较WI3孕穗至开花、开花至灌浆期NAR分别提高4.5%、4.8%,穗数和千粒重分别提高5.7%和6.9%,WGI1、WGRI2较WI3穗数、穗粒数与千粒重差异不显著。(2)绿肥还田提高了减量灌水小麦的花后干物质积累量和对籽粒的贡献率。I2、I1较I3花后干物质积累量和对籽粒的贡献率分别降低8.8%、5.3%和23.1%、13.7%;WG、WGR较W花后干物质积累量和对籽粒的贡献率分别提高19.6%、8.9%和14.0%、9.3%;与WI3相比,WGI2、WGRI2花后干物质积累量差异不显著。在干旱绿洲灌区,麦后复种绿肥是实现小麦生育期减量灌水的可行措施,绿肥可通过优化小麦光合产物的累积和分配补偿由于减量灌水造成的小麦减产,绿肥全量还田的节水潜力更高。

宽窄行播种对滴灌冬小麦干物质积累及产量的影响

为探索提高滴灌冬小麦产量的适宜播种行距,于2021—2023年设置3种宽窄行和15 cm等行距(CK)田间试验,宽窄行播种行距分别是13.3 cm+13.3 cm+13.3 cm+20 cm(M1)、10 cm+10 cm+10 cm+30 cm(M2)、10 cm+10 cm+10 cm+20 cm(M3),分析不同播种行距对滴灌冬小麦的叶面积指数、干物质积累及产量构成因素的影响。结果表明,宽窄行播种方式能维持小麦较高的叶面积指数,提高干物质积累能力及花后干物质对籽粒贡献能力;M2处理产量最高,为8984.90 kg·hm^(-2),分别较CK、M1、M3处理提高了12.16%、6.78%、6.63%。在本试验条件下,10 cm+10 cm+10 cm+30 cm宽窄行播种更有利于新疆滴灌冬小麦干物质积累和产量的提高。

加压煮制对干面条煮制品质的影响

加压煮制能够改善干面条煮制品质,但其作用机理还不清楚。研究以小麦和燕麦干面条为实验材料,探究不同的煮制压力对其品质的影响机制。随着煮制压力的增加(常压+0 kPa~常压+60 kPa),小麦干面条的吸水率增加了55.71%,吸收的水分均以自由水(T 23)为主。加压煮制通过快速吸水改善了小麦干面条的感官与质构特性,煮后面条蛋白网络连接点密度降低、蛋白平均长度降低,末端点率、孔隙度和内部糊化程度增加。随着燕麦粉质量分数(0%~40%)的增加,燕麦干面条适口性变差;燕麦添加量相同时,加压煮制(常压+60 kPa)比常压煮制T 23含量提高了11%;蛋白网络连接点密度增加、孔隙度减小,感官和质构特性得到改善;加压煮制燕麦质量分数为30%时干面条品质与常压下燕麦质量分数为10%干面条相当。加压煮制可以改善小麦和燕麦干面条的吸水率,提高了煮面效率,改善了干面条煮制品质。

播种方式对旱地春小麦产量、干物质及水分利用效率的影响

为提高新疆旱地春小麦产量及水分利用效率,筛选出适宜的播种方式,采用单因素随机区组试验,设置传统平作(T1)、起垄沟播(T2)、起垄覆膜沟播(T3)3个播种方式,研究不同播种方式下旱地的土壤含水量及春小麦的叶面积指数(leaf area index,LAI)、干物质量、产量,并进一步比较土壤贮水量、耗水量及水分利用效率等。结果表明,在抽穗期之前,T2和T3处理均可显著增加旱地春小麦的LAI和干物质量;在抽穗期之后,T3处理较T2和T1处理更有利于提高旱地春小麦的LAI和干物质量。同时,T3处理可显著提高拔节期土壤0—80 cm土层的含水量和贮水量,分别较T2、T1处理显著提高32.09%、34.64%和38.20%、38.85%;T3处理降低了播种—拔节期土壤耗水量,增加了拔节期—收获期的土壤耗水量,有利于植株中、后期的生长发育。T3处理可提高旱地春小麦的有效穗数、单穗粒数、籽粒产量、水分利用效率和降水利用效率,其中产量最高为2474.43 kg·hm^(-2),较T1、T2处理分别显著增加50.13%和50.47%;水分利用效率和降水利用效率分别显著提高48.99%、51.02%和49.41%、50.15%。综上所述,起垄覆膜沟播有利于小麦增产和水分高效利用,为新疆旱地春小麦蓄水保墒和高产高效提供了理论依据及技术参考。

夜间增温对灌浆期高温胁迫下小麦干物质及灌浆特性的影响

为了解灌浆期高温胁迫下小麦生产力对不同阶段夜间增温的反应,以对温度敏感性不同的两个小麦品种扬麦18(春性品种)和烟农19(半冬性品种)为试验材料,采用可移动塑料增温棚,于2021-2022年对小麦进行不同阶段夜间增温[分蘖期-拔节期增温(W T-J N)、拔节期-孕穗期增温(W J-B N)和孕穗期-开花期增温(W B-A N)]及灌浆期高温胁迫处理,比较分析了不同处理下小麦干物质积累及灌浆特性的差异。结果表明,W T-J N和W J-B N处理主要通过缩短小麦播种-开花的时长,延长灌浆期天数,增加花前干物质转运量、花后干物质积累量和花后干物质积累贡献率,进而提高了开花期和成熟期干物质积累量;促进了干物质在成熟期穗轴+颖壳和籽粒中的积累,降低了小麦茎鞘+叶片中的积累量,增产3.08%~7.62%。灌浆期高温胁迫显著降低了两个品种的产量,而与灌浆期高温胁迫处理(NH)相比,W T-J H和W J-B H处理增产1.21%~6.05%。与不增温处理(NN)相比,在W T-J N和W J-B N处理下两个小麦品种的灌浆期粒重及灌浆速率均提高,W B-A N和NH处理则降低了小麦灌浆参数。这说明分蘖期-拔节期和拔节期-孕穗期夜间增温可提高小麦开花期和成熟期的干物质积累量,促进小麦籽粒灌浆,缓解灌浆期高温胁迫对小麦生产力的不利影响,有助于小麦产量形成。

施氮对陇中黄土高原旱作麦田N_(2)O和CO_(2)排放的影响

【目的】探究陇中黄土高原半干旱区旱作麦田土壤N_(2)O和CO_(2)排放对不同施氮量的响应,阐明旱作麦田N_(2)O和CO_(2)排放特征及其主要影响因素,以期为该地区旱作麦田温室气体减排和氮肥管理提供依据。【方法】以陇中黄土高原旱作麦田为研究对象,采用大田定位试验和室内指标测定相结合的方法,布设CK(不施肥)、LN(低量氮肥)、MN(中量氮肥)和HN(高量氮肥)共4个施氮梯度,分析不同施氮量对旱作麦田土壤硝态氮(NO_(3)^(-)-N)、铵态氮(NH_(4)^(+)-N)、有机碳(SOC)、土壤温度、含水量及土壤N_(2)O和CO_(2)排放的影响。【结果】0~10 cm土层土壤中,HN、MN、LN较CK处理,NO_(3)^(-)-N平均含量增幅为21.55%、26.06%和34.11%;NH_(4)^(+)-N平均含量增幅为21.77%、31.42%和39.20%;SOC平均含量增幅为20.43%、25.80%和35.9%。HN、MN、LN较CK处理,N_(2)O累计排放量增幅为78.63%、130.47%、217.51%;CO_(2)累计排放量增幅为5.73%、10.63%、21.75%。皮尔逊相关关系表明,不同施氮处理中,麦田0~10 cm土层土壤中NO_(3)^(-)-N、NH_(4)^(+)-N和SOC平均含量与N_(2)O、CO_(2)累计排放量呈极显著正相关关系(P<0.001),土壤温度与N_(2)O和CO_(2)累计排放量呈显著正相关关系(P<0.05),土壤含水量与N_(2)O累计排放量呈显著的负相关关系(P<0.05),与CO_(2)累计排放量相关关系不显著。【结论】施氮可以增加黄土高原旱作麦田表层土壤中NO_(3)^(-)-N、NH_(4)^(+)-N和SOC含量,进而增加了N_(2)O和CO_(2)累计排放量,是该地区麦田N_(2)O和CO_(2)排放的主要驱动因子,表层土温和土壤含水量也一定程度上影响着N_(2)O和CO_(2)的排放。

不同覆盖处理对冬小麦干物质积累转运及产量的影响

于2020—2022年开展2 a大田试验,设置秸秆带状覆盖3行(SM3)、秸秆带状覆盖4行(SM4)、秸秆带状覆盖5行(SM5)与地膜覆盖(PM)4个处理,以露地不覆盖(CK)为对照,分析不同覆盖处理对冬小麦返青后干物质积累、花前花后营养器官干物质积累分配与转运以及籽粒产量和经济效益的影响。结果表明,与CK相比,各覆盖处理均可增加冬小麦拔节后地上部干物质积累量,提高平均生长速率和最大相对生长速率;秸秆带状覆盖处理生育期天数、快速生长阶段表现为延长,PM处理则相反。覆盖措施促进了干物质在穗轴+颖壳中的分配,提高了花前营养器官干物质向籽粒的转运量和贡献率,处理间表现为PM>SM5>SM3>SM4。与CK相比,两个生长季秸秆带状覆盖处理增产1.94%~18.43%,SM5处理产量最高;PM处理增产18.47%~27.28%。经济效益分析表明,秸秆带状覆盖处理产投比显著高于PM处理,且SM5处理纯收益最高,较CK增加989.81~1351.69 CNY·hm^(-2)。综上,覆盖处理有利于冬小麦地上干物质积累和花前干物质向籽粒的转运,其中秸秆带状覆盖5行措施增产、增收综合效果最优,是西北旱地小麦可持续发展的适宜栽培模式。

不同灌溉定额对北疆春小麦生长和水分利用效率的影响

[目的]研究不同灌溉定额对北疆滴灌春小麦生长及水分利用效率的影响,确定北疆滴灌春小麦的适宜灌溉定额。[方法]采用田间小区试验,以强筋高产品种“新春37号”和“新春44号”为研究对象,设置重度干旱(灌溉定额为4500 m^(3)/hm^(2),W1)、轻度干旱(灌溉定额为5250 m^(3)/hm^(2),W2)、正常灌水(灌溉定额为6000 m^(3)/hm^(2),W3)和过度灌溉(灌溉定额为6750 m^(3)/hm^(2),W4)4个灌溉定额,结合Logistic方程研究不同灌溉定额对北疆春小麦生长发育、产量及水分利用效率的影响。[结果]0~60 cm土层的土壤含水率随灌溉定额的增加而上升,其中0~20cm土层含水率变化最为明显。随着灌溉定额的增加,2个品种的春小麦株高、干物质积累量均呈先增加后降低的趋势。新春37号灌浆期持续时间长于新春44号。与W4处理相比,新春37号W3处理水分利用效率显著提高30%,新春44号W3处理水分利用效率显著提高15.45%。与W4处理相比,新春37号W3处理灌溉水利用效率显著提高33.91%,新春44号W3处理灌溉水利用效率提高19.85%;W3处理下的产量最高,新春37号W3处理较W1、W2、W4处理提高14.45%~38.24%;新春44号W3处理较W1、W2处理分别提高25.76%、14.45%。[结论]综合考虑产量与水分利用效率,北疆春小麦的适宜灌溉定额为6000 m^(3)/hm^(2)。