Effects of paclobutrazol application on plant architecture,lodging resistance,photosynthetic characteristics,and peanut yield at different single-seed precise sowing densities

The key to high-yielding peanut cultivation is the optimization of agricultural production practices.Regulating single-seed precise sowing(SSPS)density and paclobutrazol(Pbz)application concentration are effective practices that increase peanut yield by improving plant architecture,lodging resistance,and photosynthetic characteristics.Therefore,we conducted a two-factor field optimization experiment for the sowing density(D1:1.95×10^(5)plants ha^(-1),D52:2.40×10plants ha^(-1),D3:2.85×10^(5)plants ha^(-1),and D4:3.30×10^(5)plants ha^(-1))and Pbzapplication concentration(P0:0 mg L^(-1)and P1:100 mg L^(-1)).The objective was to optimize agricultural production practices and provide a theoretical basis for highyielding peanut cultivation by evaluating the effects of sowing density and Pbzapplication on plant architecture,lodging resistance,photosynthetic characteristics,and yield.The results showed that at the same Pbzapplication concentration,increasing sowing density increased lodging percentage and reduced leaf photosynthetic capacity.At the same sowing density,Pbzapplication reduced lodging percentage by decreasing plant height(PH),improving lignin biosynthesis-related enzyme activities,and enhancing stem puncture strength(SPS)and breaking strength(SBS).The paclobutrazol-induced alterations in plant architecture and lodging resistance improved light transmission at the middle and bottom leaf strata,resulting in the increase in relative chlorophyll content and net photosynthetic rate(Pn)of leaves.Furthermore,D3P1treatment had the highest peanut yield among all treatments.In summary,the production strategy combining the sowing density of 2.85×10^(5)plants ha^(-1)with the application of100 mg L^(-1)Pbzwas found to be the optimal agricultural production practice for giving full play to production potential and achieving higher peanut yield.

Effects of Applying Organic Fertilizer on Rice Lodging Resistance and Yield

[Objective]The aim was to provide a scientific basis for the reasonable application of organic fertilizer to improve lodging resistance and yield of rice.[Method]The application of four different kinds of organic fertilizer was applied to study their effects on rice lodging resistance and yield of late rice Yuzhengxiang that with high quality.[Result] The effect of applying organic fertilizer for improving rice lodging resistance capability was:biogas residues> chicken manure > rapeseed cake> tobac...

Effects of Planting Density and Nitrogen Amount on Stalk Lodging-Resistance and Yield of Summer Maize in Sichuan Basin

[Objective] The experiment was conducted to explore the suitable planting density and nitrogen amount for summer maize in Sichuan Basin with the objective to provide technical reservation and scientific basis for high-yielding cultivation technique.[Method] A widely planted maize cultivar ＇Chengdan 30＇ was used as experimental material to study the effects of planting density and nitrogen amount on the stalk agronomic traits,stalk lodging-resistance mechanical characters,stalk breaking percentage and yield of maize.Experiment was arranged in a two-factor split plot design with three replicates.The planting density was the main factor with three density gradients（4.5×10^4,6.0×10^4 and 7.5×10^4 plants/hm^2） and the nitrogen amount was the second factor with two different levels of nitrogen content（300 and 375 kg/hm^2）.[Result] The stalk lodging-resistance and yield were affected by planting density significantly.The increase of planting density would result in an increase of internode length and decrease of internode diameter,dry matter weight of per unit stalk length,rind penetration strength and breaking resistance of 3rd and 4th basal internodes.When planting density increased from 6.0×10^4 plants/hm2 to 7.5×10^4 plants/hm^2,the stalk breaking percentage in the whole growing season increased by 17.17%,and the yield reduced by 17.58%.The interaction between planting density and nitrogen amount affected the stalk breaking percentage in the whole growing season and yield significantly.The treatment with planting density of 6.0×104 plants/hm^2 and nitrogen amount of 375 kg/hm^2 of pure N was an optimal combination,which may not only control the stalk breaking percentage of whole growing stage effectively,but also could obtain an optimum grain yield.[Conclusion] In Sichuan Basin,the appropriate planting density and nitrogen amount for summer maize were 6.0×10^4 plants/hm^2 and 375 kg/hm^2.

Effects of Four Kinds of Plant Growth Regulators on Maize Yield and Lodging Resistance

The research reviewed use effects of Yuhuangjin, Xishibao, Zhuangfengling and Jianzhuangsu on Jinhai No. 5. The results showed plant height and ear height declined in varying degrees, as well as empty-stalk rate and lodging rate, with the plant growth regulators applied. Economic characters all improved, including ear length and diameter, barren-tip length and hundred-seed weight, and corn yield went up significantly on average. For example, the increased yield can be as high as 17.43% when Yuhuangjin was applied at 30 ml/hm^2.

Delayed sowing can increase lodging resistance while maintaining grain yield and nitrogen use efficiency in winter wheat

Lodging resistance of winter wheat(Trnticum aestivum L.) can be increased by late sowing.However, whether grain yield and nitrogen use efficiency(NUE) can be maintained with delayed sowing remains unknown. During the 2013-2014 and 2014-2015 growing seasons, two winter wheat cultivars were sown on three dates(early sowing on October 1, normal so,wing on October8, and late sowing on October 15) to investigate the responses of lodging resistance, grain yield,and NUE to sowing date. No significant differences in lodging resistance, grain yield, or NUE between early and normal sowing were observed. Averaging over the two cultivars and years,postponing the sowing date significantly increased lodging resistance by 53.6% and 49.6%compared with that following early and normal sowing, respectively. Lodging resistance was improved mainly through a reduction in the culm height at the center of gravity and an increase in the tensile strength of the base internode. Late sowing resulted in similar grain yield as well as kernel weight and number of kernels per square meter, compared to early and normal sowing.Averaging over the two cultivars and years, delayed sowing resulted in a reduction in nitrogen uptake efficiency(UPE) by 11.0% and 9.9% compared to early and normal sowing, respectively,owing to reduced root length density and dry matter accumulation before anthesis. An average increase in nitrogen utilization efficiency(UTE) of 12.9% and 11.2% compared to early and normal sowing, respectively, was observed with late sowing owing to a reduction in the grain nitrogen concentration. The increase in UTE offset the reduction in UPE, resulting in equal NUEs among all sowing dates. Thus, sowing later than normal could increase lodging resistance while maintaining grain yield and NUE.

Effects of different mechanical direct seeding methods on grain yield and lodging resistance of early indica rice in South China

Direct seeding of rice has become a main planting method due to the low labor input and high economic benefit in South China.Dry direct seeding(DDS)has been widely used for single-season rice planting establishment.However,few studies have examined the performance of early-season indica rice under mechanical dry direct seeding.A two-year field experiment was conducted with two indica rice cultivars(i.e.,Zhongjiazao 17 and Zhuliangyou 819)to study lodging characteristics and grain yield formation under DDS,flooded direct seeding(FDS)and wet direct seeding(WDS)patterns.The results showed that the annual grain yield in DDS was higher by 14.42–26.34%for cultivar ZLY819 and 6.64–24.58%for cultivar ZJZ17 than in WDS and FDS,respectively,and these increases were mainly attributed to the improvement of the panicles.The DDS pattern significantly increased the seedling emergence rate of early indica rice cultivars,and increased total dry weight and crop growth rate.Meanwhile,shorter basal internodes,better stem diameter and stem wall thickness and lower lodging index were found in DDS in contrast to FDS and WDS.In particular,DDS improved the stem lodging resistance.Our results suggested that the appropriate direct seeding method was beneficial for improving the grain yield and lodging resistance of early indica rice.

Characteristics of lodging resistance of high-yield winter wheat as affected by nitrogen rate and irrigation managements

High yields of wheat are mainly obtained through a high level of nitrogen and irrigation supplementation.However,excessive nitrogen and irrigation supplication increase the risk of lodging.The main objectives of this work were to clarify the capacity of lodging resistance of wheat in response to nitrogen and irrigation,as well as to explore the effective ways of improving lodging resistance in a high-yield wheat cultivar.In this study,field experiments were conducted in the 2015-2016 and 2016-2017 growing seasons.A wheat cultivar Jimai 22(JM22),which is widely planted in the northern of Huang-Huai winter wheat region,was grown at Tai’an,Shandong Province,under three nitrogen rates and four irrigation treatments.The lodging risk was increased with increased nitrogen rate,as indicated by increasing lodging index(LI)and lodging rate across both growing seasons.With nitrogen increasing,the plant height,the basal internode length and the center of gravity height,which were positively correlated with LI,increased significantly.While the density of the basal 2nd internode(for culm and leaf sheath)and cell wall component contents,which were negatively correlated with LI,decreased conspicuous along with nitrogen increased.Increasing irrigation supplementation increased the 2nd internode culm wall thickness,breaking strength and leaf sheath density within limits which increased stem strength.Among the treatments,nitrogen application at a rate of 240 kg ha^(-1) and irrigation application at 600 m^(3)ha^(-1) at both the jointing and anthesis stages resulted in the highest yield and strongest stem.A suitable plant height ensures suffcient biomass for high yield,and higher stem stiffness,which was primarily attributed to thicker culm wall,greater density of the culm and leaf sheaths and higher cell wall component contents are the characteristics that should be taken into account to improving wheat lodging resistance.

Research progress on reduced lodging of high-yield and-density maize

Increasing plant density is an effective way to enhance maize yield, but often increases lodging rate and severity, significantly elevating the risk and cost of maize production. Therefore, lodging is a major factor restricting future increases in maize yield through high-density planting. This paper reviewed previous research on the relationships between maize lodging rate and plant morphology, mechanical strength of stalks, anatomical and biochemical characteristics of stalks, root characteristics, damage from pests and diseases, environmental factors, and genomic characteristics. The effects of planting density on these factors and explored possible ways to improve lodging resistance were also analyzed in this paper. The results provide a basis for future research on increasing maize lodging resistance under high-density planting conditions and can be used to develop maize cultivation practices and lodging-resistant maize cultivars.

Effects of nitrogen fertilizer and chemical regulation on spring maize lodging characteristics, grain filling and yield formation under high planting density in Heilongjiang Province, China

Now,lodging is a major constraint factor contributing to yield loss of maize (Zea mays L.) under high planting density.Chemical regulation and nitrogen fertilizer could effectively coordinate the relationship between stem lodging and maize yield,which significantly reduce lodging and improve the grain yield.The purpose of this study was to explore the effects of chemical regulation and different nitrogen application rates on lodging characteristics,grain filling and yield of maize under high density.For this,we established a field study during 2017 and 2018 growing seasons,with three nitrogen levels of N100 (100 kg ha^(–1)),N200 (200 kg ha^(–1)) and N300 (300 kg ha^(–1)) at high planting density (90 000 plants ha^(–1)),and applied plant growth regulator (Yuhuangjin,the mixture of 3% DTA-6 and 27% ethephon) at the 7th leaf.The results showed that chemical control increased the activities of phenylalanine ammonia-lyase (PAL),tyrosine ammonia-lyase (TAL),4-coumarate:Co A ligase (4CL),and cinnamyl alcohol dehydrogenase (CAD),and increased the lignin,cellulose and hemicellulose contents at the bottom of the 3rd internode,which significantly reduced the lodging percentage.The lignin-related enzyme activities,lignin,cellulose and hemicellulose contents decreased with the increase of nitrogen fertilizer,which significantly increased the lodging percentage.The 200 kg ha^(–1) nitrogen application and chemical control increased the number,diameter,angle,volume,and dry weight of brace roots.The 200 kg ha^(–1) nitrogen application and chemical control significantly increased the activities of ADP-glucose pyrophosphorylase (AGPase),soluble starch synthase (SSS) and starch branching enzyme(SBE),which promoted the starch accumulation in grains.Additional,improved the maximum grain filling rate (V_(max)) and mean grain filling rate (V_(m)),which promoted the grain filling process,significantly increased grain weight and grain number per ear,thus increased the final yield.

Lodging Resistance Related to Root Traits for Mechanized Wet-Seeding of Two Super Rice Cultivars

Mechanical hill wet-seeded rice machine is beneficial for establishing and growing uniform rows of seedlings.However,there is limited knowledge regarding the effects of the establishment of furrows on growth,lodging and yield,and their relationships with root traits.In this study,field experiments were conducted during 2012 and 2013 using two super rice varieties(hybrid rice Peizataifeng and inbred rice Yuxiangyouzhan)under three furrow establishment treatments(T1,both water and seed furrows were established by the machine;T2,only seed furrows were established by the machine;and T3,neither water nor seed furrows were established by the machine).Lodging index,lodging-related traits,grain yield,above-ground dry weight and root traits were measured.The results showed that the lodging index was significantly affected by the treatments with furrows(T1 and T2).The strongest lodging resistance was detected in the mechanical hill wet-seeded rice with furrow treatment(T1)in both 2012 and 2013.Lodging resistance was strongly related to the breaking resistance.No significant difference was found in grain yield or dry weight of the mechanical hill wet-seeded rice.Therefore,the mechanical hill wet-seeded rice with furrow treatment increased rice lodging resistance,which was related to root traits.

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.

植物生长调节剂在胡麻上的应用效果研究

为探讨植物生长调节剂在胡麻生产中的应用效果,通过田间试验研究烯效唑和多效唑对现蕾期和盛花期胡麻生长、叶片生物酶活性及产量的影响,以期为胡麻化控栽培提供科学依据。结果表明,2种生长调节剂在胡麻现蕾期和盛花期分2次喷施均可以明显降低胡麻的株高和重心高度,明显增加茎粗,进而影响胡麻产量形成。4个喷施植物生长调节剂的处理在胡麻现蕾期和盛花期,与清水对照相比,平均株高降低15.09%和19.22%,平均重心高度降低10.47%和20.18%,平均鲜重降低7.73%和13.51%,平均茎粗增加7.69%和13.33%,且盛花期喷施的效应更加明显。现蕾期和盛花期不同处理间CAT含量、SOD含量、MDA含量均存在显著差异。随生育期的推进,CAT含量均呈明显下降趋势;SOD含量表现出不同的变化,喷施烯效唑处理和清水对照SOD含量均呈上升趋势,喷施多效唑处理均呈下降趋势;MDA含量均呈上升趋势。综上所述,喷施5%烯效唑可湿性粉剂1995 g/hm2兑水450 kg和15%多效唑可湿性粉剂1995 g/hm2兑水450 kg效果良好,能够在稳定产量的同时有效地增强抗倒伏能力。

播期和密度对精量穴直播水稻产量和抗倒伏性的影响

为探究渝西地区播期与密度互作对精量穴直播水稻产量和抗倒伏的影响,以渝香优8133和泰优粤禾丝苗为试验材料,设置2个播期(B1:3月29日、B2:5月25日)和5个播种密度(D1:每1 hm^(2)1.50×10^(5)穴、D2:每1 hm^(2)1.95×10^(5)穴、D3:每1 hm^(2)2.40×10^(5)穴、D4:每1 hm^(2)2.85×10^(5)穴、D5:每1 hm^(2)3.30×10^(5)穴),分析茎秆力学、茎秆形态及器官干物质积累与茎秆抗倒伏性和产量的关系。结果表明,与早播处理(B1)相比,迟播处理(B2)可显著提高精量穴直播水稻产量水平;同时,B2播期处理较高的叶面积指数(LAI)和有效穗数导致茎秆倒伏指数显著提高。随着播种密度增加,2个水稻品种的产量均呈先增加后降低趋势,B1播期下D3处理产量最高,B2播期下D4处理产量最高,但与D3处理差异不显著;而倒伏指数呈持续增加趋势,2个水稻品种趋势一致。与D1处理相比,B1和B2播期的D2、D3处理倒伏指数增幅较小,D4、D5处理显著升高,以渝香优8133表现明显。在B1和B2播期下,D2、D3处理的单株茎鞘干重、基部节间茎粗、壁厚及茎鞘充实度与D1处理相当,而D4、D5处理大幅降低。综合分析认为,在B1和B2播期下,D3处理是精量穴直播水稻产量、抗倒伏协同较好的适宜播种密度。

不同施氮水平下硅肥对谷子抗倒伏能力、产量和品质的影响

[目的]倒伏严重影响谷子产量和品质。探究不同施氮水平下硅肥提高谷子茎秆强度、产量及品质的作用,为谷子高产高效施肥提供技术方案。[方法]以晋谷21和张杂13为供试谷子品种,在山西太谷进行大田试验。在常规施氮量N_(1)(180 kg/hm^(2))和高施氮量N_(2)(450 kg/hm^(2))下,分别设置不施硅、施用硅酸钠(Si_(1),SiO_(2) 68.85 kg/hm^(2))和硅钙肥(Si_(2),SiO_(2) 67.2 kg/hm^(2)),共6个处理。在谷子成熟期测量其株高、抗倒伏能力相关指标、光合特性、产量和品质相关指标,并观察茎秆横切面显微结构。[结果]N_(1)水平下,施用硅肥降低了谷子基节长度,增加了茎粗、茎秆抗折力和穿刺力,晋谷21和张杂13两品种前五基节的节间长度分别降低了4.1%~30.1%和9.5%~11.5%,茎粗分别增加5.3%~19.4%和13.0%~34.1%;晋谷21抗倒性在N_(1)-Si_(1)处理较强,第一、第二基节抗倒伏指数较N_(1)-Si_0处理分别增加37.4%和35.8%,张杂13在N_(1)-Si_(2)处理时较强,第一、第二基节抗倒伏指数较N_(1)-Si_0处理分别增加136.0%和94.7%。N_(2)水平下,施用硅肥后晋谷21和张杂13前五基节的节间长度分别降低了9.6%~30.3%和10.6%~14.9%,茎粗分别增加了9.56%~23.9%和16.2%~31.0%,茎秆扁平度降低。硅钙肥对谷子茎秆强度影响大于硅酸钠,N_(2)-Si_(2)处理晋谷21的第二基节抗折力、穿刺力和抗倒伏指数比N_(2)-Si_0分别增加97.9%、77.6%和83.3%,张杂13的第一基节抗折力、穿刺力和抗倒伏指数比N_(2)-Si_0分别增加74.0%、66.8%和128%。施硅后谷子茎秆中机械组织增厚,维管束数量增多且排列均匀,向茎秆中心延伸,且在N_(2)水平下,硅钙肥作用效果优于硅酸钠。硅可促进谷子穗码发育,增加穗粗、穗粒数和千粒重,在高氮水平下硅钙肥处理使晋谷21和张杂13的产量分别增加23.8%和24.0%。施用硅肥能够提高谷子脂肪、蛋白质和氨基酸含量,在高氮水平下可以降低谷子直链淀粉/支链淀粉值。[结论]在高氮条件下,施用硅钙肥使谷子前五基节长度降低,茎粗增加,机械强度增加,进而提高抗倒伏能力;施用硅肥还可增加光合速率和蒸腾速率,促进物质积累和运输,增加产量,改善品质。

嘉兴地区大麦品种比较试验

为客观、公正地评价新育成大麦品种(系)特征特性,在嘉兴市农业科学研究院古塘基地开展2022—2023年度浙江省大麦品种比较试验,参试品种共11个,其中对照品种2个(花30、浙皮11)。结果表明,浙皮23和秀1271综合表现不错,高产、抗倒伏,适合在嘉兴地区推广种植。

不同裸燕麦品种抗倒能力及产量差异分析

为筛选抗倒伏能力强的高产裸燕麦品种,对16个裸燕麦品种的抗倒伏能力和产量进行比较,利用主成分分析和通径分析对与抗倒伏相关的7个性状进行分析。结果表明,裸燕麦品种间地上部生物量构成、主要农艺性状、茎秆基部第二节间形态及倒伏指数、产量及其构成因素均存在差异。通过主成分分析和通径分析,株高和穗位高是评价裸燕麦抗倒伏能力的关键。产量较高的白燕2号、白燕18号、花早2号的株高、穗位高较低,倒伏指数较小且田间未发现倒伏;坝莜14号、晋燕17号虽具有较高产量,但其株高、穗位高较高,倒伏指数较大,且田间分别表现为7级易倒伏和5级中抗倒伏。白燕2号、白燕18号、花早2号抗倒伏综合表现良好,产量高,适宜在内蒙古乌兰察布地区及类似地区推广种植。

种植密度与施肥水平对甜荞光合特性、产量及抗倒伏的影响

【目的】合理密植与施肥,可有效协调个体间的竞争,改善群体光环境,构建高产群体,是提高作物高产的重要途径。探讨不同种植密度和施肥水平对甜荞抗倒性能及产量的影响,为荞麦抗倒高产高效栽培提供技术参考。【方法】以等花柱甜荞新品种西农D4103为试验材料,黄土高原主栽品种西农9976为对照,采用双因素裂区设计,主因素为2个栽培密度,分别为D1:90万株/hm2、D2:135万株/hm2;副因素为低、中、高3个施肥水平,分别为F1(N:120、P2O5:76.8、K2O:56.4 kg·hm^(-2))、F2(N:180、P2O5:115.2、K2O:84.6 kg·hm^(-2))和F3(N:240、P2O5:153.6、K2O:112.8 kg·hm^(-2)),于2021—2022年在西北农林科技大学榆林小杂粮试验站进行。研究不同种植密度和施肥水平对甜荞群体冠层结构及光合特性、产量及产量构成因素、倒伏特性的变化规律。【结果】2年大田试验表明,提高种植密度,使甜荞群体叶面积指数(LAI)显著增加,光合有效辐射(PAR)和相对叶绿素含量(SPAD)显著下降,并减弱了叶片光合能力。施肥显著提高了甜荞群体LAI、SPAD和光合能力,降低了PAR,中肥水平较低肥水平的LAI、SPAD、净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr),平均增加14.6%、6.7%、15.3%、15.2%和16.6%,PAR和胞间CO_(2)浓度(Ci)平均减少4.5%和6.7%。D2较D1处理的株高、重心高度、第2节间长、倒伏率和倒伏指数平均增加9.6%、12.5%、24.7%、19.8%和26.2%,而第2节间粗、充实度、抗折力和整株鲜重减少13.1%、7.4%、18.3%和8.5%。同等密度下增加施肥量,使甜荞株高、重心高度、第2节间长、整株鲜重、倒伏率和倒伏指数逐渐增加,第2节间粗、第2节间充实度、第2节间抗折力呈先增加后减小的趋势。提高种植密度和施肥水平,使甜荞产量显著增加,西农D4103的产量在D2F2处理下达最大值,较D1F1增产15.1%,较对照品种在同等施肥量下增产17.0%。【结论】构建合理的甜荞群体结构有利于增加群体受光面积,改善光合特性,降低田间倒伏率,从而提高产量。因此,黄土高原地区等花柱甜荞品种西农D4103推荐种植密度为135万株/hm2,肥料施用量为中等施肥水平(N:180 kg·hm^(-2)、P2O5:115.2 kg·hm^(-2)、K2O:84.6 kg·hm^(-2))。

氮肥与种植密度对春玉米产量及抗倒伏性能的调控效应

【目的】适宜的密度与氮肥运筹是提高玉米抗倒伏能力、保证高产稳产和提高生产效益的重要措施。探讨不同施氮量与种植密度对春玉米产量及抗倒伏性能的影响,以期为山西春玉米的高产高效栽培及籽粒机收的发展提供理论支撑。【方法】于2018和2019年在山西晋中进行玉米田间试验,供试玉米品种为‘郑单958’。设置4个施氮水平:0、120、180、240 kg/hm^(2) (N0、N1、N2、N3);3个种植密度:60000、75000、90000株/hm^(2)(D1、D2、D3)。调查玉米吐丝期茎秆农艺性状,生理成熟期穗位以下茎秆生物学、力学性状及倒伏率,并测定产量。【结果】随着种植密度和施氮量的增加,玉米产量呈先增加后降低的趋势。在D2密度下达到最高值,两年平均产量为13792 kg/hm^(2),较D1和D3密度下分别增加了4.8%和8.3%。与N0相比,N1、N2和N3处理分别增产24.3%、26.7%和23.9%。N3处理对穗粒数与千粒重无显著影响,但产量低于N1和N2处理。增密导致玉米茎秆变细,株高、穗位上升,玉米第3~6节长粗比增加,穿刺强度、抗压强度、抗弯折力等茎秆力学特性变差。D2和D3密度下两年玉米平均倒伏率较D1分别升高了1.33、3.73个百分点。N1、N2、N3处理两年玉米平均倒伏率较N0分别增加了2.50、3.25、4.80个百分点。适当增氮有利于消减因密度增加导致的生物学、力学特性变差,D2和D3密度下,N2处理第3~6节穿刺强度、抗压强度和抗弯折力维持在较高水平,显著高于N3处理。【结论】合理的氮肥用量可改善因密度增加导致的茎秆细弱、玉米茎秆力学特性变差问题,降低倒伏风险,因而增加产量。在山西中部春玉米种植区,种植密度为75000株/hm^(2)、施氮量180 kg/hm^(2),是玉米产量、茎秆力学特性及抗倒性能和谐的密度肥料组合。

施钾量与密度对胡麻木质素合成积累及抗倒伏特性的调控

为探索胡麻木质素代谢与抗倒伏性能对钾肥和密度的响应规律,以‘陇亚11号’胡麻为供试材料,设置施钾(K_(2)O)量(0 kg·hm^(-2)、60 kg·hm^(-2)、90 kg·hm^(-2)分别记作K0、K1、K2)和种植密度(6.0×106株·hm^(-2)、7.5×106株·hm^(-2)、9.0×106株·hm^(-2)分别记作D1、D2、D3)二因素随机区组试验,研究施钾和密度对胡麻茎秆抗折力、抗倒伏指数、木质素代谢关键酶活性、木质素含量及分布和产量构成的影响。结果表明,随着胡麻生育时期的推进,PAL、TAL活性迅速增加,在青果期达到最大值;青果期,各钾肥水平PAL、TAL活性较K0水平显著升高2.90%~16.78%、12.39%~33.72%,中密度D2水平下木质素含量较其他密度水平显著增加1.32%~14.01%,茎秆抗折力和抗倒伏指数均达到最大值,与其他密度水平差异显著;密度/钾肥互作条件下,生育后期,D2K1处理显著提高了木质素生物合成酶活性(TAL和PAL)和茎秆横截面积,促进了胡麻茎秆中木质素的合成积累,显著提高了茎秆抗折力和抗倒伏指数,籽粒产量显著增加15.67%~67.48%。相关性分析表明,茎秆抗折力和抗倒伏指数、茎秆抗折力和木质素含量以及抗倒伏指数和木质素含量在青果期均呈显著正相关关系。

增密扩行对宽幅匀播胡麻抗倒伏能力及籽粒产量的影响

为进一步提高旱作农业区胡麻(Linum usitatissimum L.)抗倒伏能力和籽粒产量,本研究以胡麻品种定亚26为试验材料,于2021年通过田间裂区试验,研究了宽幅(10 cm)播种技术下增密(750、850和950粒·m^(-2))扩行(15、20和25 cm行距)对胡麻抗倒伏性和产量的影响。结果表明,随着胡麻种植密度的增加,植株株高和重心高度均增大,850和950粒·m^(2)分别较常规播种密度(750粒·m^(2))平均增加8.96%和9.13%,茎粗、单株鲜重、茎秆强度、抗折力和抗倒伏指数分别降低9.58%、18.08%、11.11%、34.30%和22.46%,差异达显著水平。在950粒·m^(-2)密度水平下,与常规条播相比,宽幅匀播有利于缓解胡麻株高的快速增长,增大茎粗,增强茎秆抗倒伏能力,其中10 cm幅宽处理下15和20 cm行距青果期茎秆强度、抗折力、抗倒伏指数分别提高1.71%和10.67%、6.58%和19.30%、13.62%和20.71%,且差异达显著水平;籽粒产量显著高出19.85%~30.46%,其中,20 cm行距处理下籽粒产量最高,达1884.44kg·hm^(-2)。综上,10 cm幅宽和20 cm行距配合950粒·m^(-2)种植密度有利于提高陇中旱作农业区胡麻的抗倒伏能力和籽粒产量。本研究结果为旱作农业区胡麻抗逆高产栽培模式提供了技术参考。