Soybean maize strip intercropping:A solution for maintaining food security in China

The practice of intercropping leguminous and gramineous crops is used for promoting sustainable agriculture,optimizing resource utilization,enhancing biodiversity,and reducing reliance on petroleum products.However,promoting conventional intercropping strategies in modern agriculture can prove challenging.The innovative technology of soybean maize strip intercropping(SMSI)has been proposed as a solution.This system has produced remarkable results in improving domestic soybean and maize production for both food security and sustainable agriculture.In this article,we provide an overview of SMSI and explain how it differs from traditional intercropping.We also discuss the core principles that foster higher yields and the prospects for its future development.

Maize-soybean strip intercropping： Achieved a balance between high productivity and sustainability

Intercropping is one of the most vital practice to improve land utilization rate in China that has limited arable land resource. However, the traditional intercropping systems have many disadvantages including illogical field lay-out of crops, low economic value, and labor deficiency, which cannot balance the crop production and agricultural sustainability. In view of this, we developed a novel soybean strip intercropping model using maize as the partner, the regular maize-soybean strip intercropping mainly popularized in northern China and maize-soybean relay-strip intercropping principally extended in southwestern China. Compared to the traditional maize-soybean intercropping systems, the main innovation of field lay-out style in our present intercropping systems is that the distance of two adjacent maize rows are shrunk as a narrow strip, and a strip called wide strip between two adjacent narrow strips is expanded reserving for the growth of two or three rows of soybean plants. The distance between outer rows of maize and soybean strips are expanded enough for light use efficiency improvement and tractors working in the soybean strips. Importantly, optimal cultivar screening and increase of plant density achieved a high yield of both the two crops in the intercropping systems and increased land equivalent ratio as high as 2.2. Annually alternative rotation of the adjacent maize-and soybean-strips increased the grain yield of next seasonal maize, improved the absorption of nitrogen, phosphorus, and potasium of maize, while prevented the continuous cropping obstacles. Extra soybean production was obtained without affecting maize yield in our strip intercropping systems, which balanced the high crop production and agricultural sustainability.

Effect of Limited Single Irrigation on Yield of Winter Wheat and Spring Maize Relay Intercropping

A field experiment was conducted during the 2002/2003 cropping season of winter wheat （Triticum aestivum） and spring maize （Zea mays） to evaluate the effect of limited single drip irrigation on the yield and water use of both crops under relay intercropping in a semi-arid area of northwestern China. A controlled 35 mm single irrigation, either early or late, was applied to each crop at a certain growth stage. Soil water, leaf area, final grain yield and yield components such as the thousand-grain weight, length of spike, fertile spikelet number, number of grains per spike, and grain weight per spike were measured, and water use efficiency and leaf area index were calculated for the irrigated and non-irrigated relay intercropping treatments and sole cropping controls. The results showed that yield, yield components, water use efficiency, and leaf area index in the relay intercropping treatments were affected by limited single drip irrigation during various growth stages of wheat and maize. The total yields in the relay intercropping treatment irrigated during the heading stage of wheat and the heading and anthesis stage of maize were the highest among all the treatments, followed by that irrigated during the anthesis stage of wheat and silking stage of maize; so was the water use efficiency. Significant differences occurred in most yield components between the irrigated and non-irrigated relay-intercropping treatments. The dynamics of the leaf area index in the relay-intercropped or solely cropped wheat and maize showed a type of single-peak pattern, whereas that of the relay intercropping treatments showed a type of double-peak pattern. Appropriately, limited single irrigation and controlled soil water content level could result in higher total yield, water use efficiency, and leaf area index, and improved yield components in relay intercropping. This practice saved the amount of water used for irrigation and also increased the yield. Therefore, heading stage of wheat and heading and anthesis stage of maize were suggested to be the optimum limited single irrigation time for relay-intercropped wheat and maize in the semi-arid area.

Effects of maize-soybean relay intercropping on crop nutrient uptake and soil bacterial community

Maize-soybean relay intercropping is an effective approach to improve the crop yield and nutrient use efficiency,which is widely practiced by farmers in southwest of China.To elucidate the characteristics of different planting patterns on crop nutrient uptake,soil chemical properties,and soil bacteria community in maize-soybean relay intercropping systems,we conducted a field experiment in 2015–2016 with single factor treatments,including monoculture maize(MM),monoculture soybean(MS),maize-soybean relay intercropping(IMS),and fallow(CK).The results showed that the N uptake of maize grain increased in IMS compared with MM.Compared with MS,the yield and uptake of N,P,and K of soybean grain were increased by 25.5,24.4,9.6,and 22.4%in IMS,respectively,while the N and K uptakes in soybean straw were decreased in IMS.The soil total nitrogen,available phosphorus,and soil organic matter contents were significantly higher in IMS than those of the corresponding monocultures and CK.Moreover,the soil protease,soil urease,and soil nitrate reductase activities in IMS were higher than those of the corresponding monocultures and CK.The phyla Proteobacteria,Acidobacteria,Chloroflexi,and Actinobacteria dominated in all treatments.Shannon’s index in IMS was higher than that of the corresponding monocultures and CK.The phylum Proteobacteria proportion was positively correlated with maize soil organic matter and soybean soil total nitrogen content,respectively.These results indicated that the belowground interactions increased the crop nutrient(N and P)uptake and soil bacterial community diversity,both of which contributed to improved soil nutrient management for legume-cereal relay intercropping systems.

Relay-intercropping soybean with maize maintains soil fertility and increases nitrogen recovery efficiency by reducing nitrogen input

Optimized nitrogen(N)management can increase N-use efficiency in intercropping systems.Legume-nonlegume intercropping systems can reduce N input by exploiting biological N fixation by legumes.Measurement of N utilization can help in dissecting the mechanisms underlying N uptake and utilization in legume-nonlegume intercropping systems.An experiment was performed with three planting patterns:monoculture maize(MM),monoculture soybean(SS),and maize-soybean relay intercropping(IMS),and three N application levels:zero N(NN),reduced N(RN),and conventional N(CN)to investigate crop N uptake and utilization characteristics.N recovery efficiency and 15N recovery rate of crops were higher under RN than under CN,and those under RN were higher under intercropping than under the corresponding monocultures.Compared with MM,IMS showed a lower soil N-dependent rate(SNDR)in 2012.However,the SNDR of MM rapidly declined from 86.8%in 2012 to 49.4%in 2014,whereas that of IMS declined slowly from 75.4%in 2012 to 69.4%in 2014.The interspecific N competition rate(NCRms)was higher under RN than under CN,and increased yearly.Soybean nodule dry weight and nitrogenase activities were respectively 34.2%and 12.5%higher under intercropping than in monoculture at the beginning seed stage.The amount(Ndfa)and ratio(%Ndfa)of soybean N2 fixation were significantly greater under IS than under SS.In conclusion,N fertilizer was more efficiently used under RN than under CN;in particular,the relay intercropping system promoted N fertilizer utilization in comparison with the corresponding monocultures.An intercropping system helps to maintain soil fertility because interspecific N competition promotes biological N fixation by soybean by reducing N input.Thus,a maize-soybean relay intercropping system with reduced N application is sustainable and environmentally friendly.

不同带宽行比对玉米/大豆带状间套作群体产量和氮素效率的影响

为明确玉米/大豆带状间套作的最优配置,大田试验条件下,以单作玉米(MM)和单作大豆(MS)为对照,设置5种不同带宽行比:2 m带宽玉豆行数比为2∶2(T1)、2.4 m带宽玉豆行数比为2∶3(T2)、2.4 m带宽玉豆行数比为2∶4(T3)、2.8 m带宽玉豆行数比为2∶3(T4)、2.8 m带宽玉豆行数比为2∶4(T5),研究不同带宽行比对玉米/大豆带状间套作群体产量和氮素利用效率的影响。结果表明,玉米籽粒产量总体上随着带宽增加呈现逐渐减少的趋势,大豆籽粒产量总体上随着带宽增加呈现逐渐增加的趋势;相同带宽条件下,随着玉米大豆行比增加,玉米籽粒产量下降,大豆籽粒产量增加;玉米和大豆的植株氮素吸收利用效率变化规律与籽粒产量基本相一致。与对照相比,T2有提高玉米和大豆的收获指数,增加氮素在玉米和大豆籽粒的分配比例、降低在茎秆的分配比例的趋势。综合产量、经济效益以及群体氮素吸收、分配和利用效率的表现,2.4 m带宽下种植2行玉米3行大豆为鄂西南山区玉米/大豆的最优间套作模式。

南充市大豆玉米带状复合种植调研报告

为了解南充市大豆玉米带状复合种植现状,文章以南充市南部县与西充县多个大豆玉米带状复合种植示范区为调研对象,对调研区的基本种植情况、存在问题进行调研,提出促进南充市大豆生产发展建议,包括优选良种,加强田间管理;推进西南丘区小型智能农机装备研发进程;提供政策扶持,加快大豆生物育种步伐,旨在为提升南充大豆单产水平提供参考,助力南充市大豆产业发展。

施氮与种间距离下大豆/玉米带状套作作物生长特性及其对产量形成的影响

为明确施氮和种间距离下套作作物生长特性及其对产量形成的影响。本文以大豆/玉米带状套作系统为研究主体,探究不同氮水平(施氮与不施氮)与种间距离(玉豆间距30、45、60和75 cm、单作100 cm)下作物生长率、干物质积累与分配及产量差异,并对作物干物质积累过程进行拟合,综合分析作物生长规律和产量效益。结果表明:玉米生长率在抽雄期至乳熟期达最大,不施氮下以间距30 cm(MS30)最高,较玉米单作(MM100)高出34.99%。套作大豆生长率在初花期前显著低于单作(SS100),而初花期后高于SS100,以间距60cm(MS60)最高,盛花期—盛荚期在不施氮下较SS100高出78.91%。Logistic方程可较好的拟合玉米、大豆的干物质积累过程,且R2均在0.95以上。与不施氮相比,施氮推迟了玉米干物质积累高峰,提高了干物质积累量;套作大豆生育前期干物质积累慢于单作,而生育后期间距45cm(MS45)、MS60干物质积累逐渐与单作持平甚至超过单作。施氮提高了玉米籽粒干物质分配率而显著提高产量,2年间玉米产量分别提高10.05%、40.90%。随种间距离增加套作大豆产量呈先增后减趋势,以MS60最高,MS30最低,MS60两年间在不施氮与施氮下较MS30分别平均高出23.88%、31.77%。套作下土地当量比均在1.35以上,其中以施氮下MS60最大(1.89)。适宜的种间距离(间距60 cm)可实现套作下玉米和大豆协同生长,提高作物生长率、促进干物质积累与分配、提高系统产量和土地当量比。

带状复合种植模式下玉米大豆性状表现与综合效益分析

于2022年引进了5个玉米品种,与鄂豆10号大豆带状复合种植,观察玉米和大豆的相关性状,筛选出适宜的玉米品种,分析综合效益。结果表明:各复合种植模式中,以MY73+鄂豆10号处理的玉米单产、总产、总产值最高,分别为6 655 kg/hm^(2)、8 030 kg/hm^(2)、26 103元/hm^(2);玉米品种MY73在试验中表现为产量最高、株高较矮、综合抗性好,是玉米大豆复合种植模式中较适宜的品种。

大豆玉米带状复合种植生产效率及其影响因素--基于黄淮海、西南、西北地区调查

【目的】提高大豆玉米带状复合种植的生产效率。【方法】基于2022年全国15省大豆玉米带状复合种植农户问卷调查,运用DEA-Tobit模型分析了大豆玉米带状复合种植户的生产效率及其影响因素。【结果】大豆玉米带状复合种植农户的生产效率普遍偏低,纯技术效率低是造成生产效率低的主要原因。生产效率在地区间存在差异,西北地区最高,西南地区最低。农业生产经营主体类型、土壤肥力对生产效率呈显著正相关关系,生产投入费用、机械播种方式、改良机械收获方式对生产效率呈显著负相关关系。【结论】提出鼓励传统农户向现代农业经营模式转变、增强农户技术认知和优化技术参数、完善专用农机设备与社会化服务以及挖掘地区优势,选择适宜推广模式等政策建议。

大豆-玉米带状复合种植模式下草地贪夜蛾的生存适应性和危害性

【目的】研究草地贪夜蛾(Spodoptera frugiperda)对大豆和玉米的取食代谢特性和迁移扩散行为,明确草地贪夜蛾在大豆-玉米带状复合种植模式下的取食规律和潜在危害风险。【方法】供试寄主植物为江苏省大豆-玉米带状复合种植推荐品种徐豆18和江玉877,室内测定大豆叶片和玉米叶片对草地贪夜蛾的取食趋性、生长发育、产卵量、产卵选择性、消化酶活性及消化代谢的影响。田间接种卵块并调查玉米-大豆“2+4”模式间作下草地贪夜蛾随时间的迁移距离和范围,根据迁移动态评估其在该种植模式下的潜在危害风险。【结果】草地贪夜蛾对玉米叶片表现出明显的取食趋向性,选择取食玉米叶片个体占63.89%,为选择取食大豆叶片个体数的1.77倍,差异显著。草地贪夜蛾取食大豆叶片和玉米叶片均能完成世代发育,但取食玉米叶片的草地贪夜蛾幼虫发育历期为14.82 d,较取食大豆叶片的幼虫发育历期缩短2.54 d,单雌产卵量为679.50粒,较取食大豆叶片增加26.58%,差异显著。成虫产卵主要选择玉米叶片,平均卵块数和单雌着卵量为5.67块和521.67粒,分别为大豆的1.70和2.04倍,差异显著。取食大豆叶片的草地贪夜蛾脂肪酶活性为9.84 U·g^(-1),较取食玉米叶片的脂肪酶活性6.47 U·g^(-1)显著提高,而两者的蛋白酶和淀粉酶活性无显著差异。取食大豆叶片的草地贪夜蛾近似消化率为63.40%,较取食玉米叶片的近似消化率69.26%显著降低,但两者在食物利用率、食物转化率和相对生长率方面无显著差异。田间接种卵块后调查发现玉米-大豆“2+4”模式间作下,草地贪夜蛾主要在玉米上扩散,于玉米种植行内“纵向迁移”,未扩散到相邻的大豆植株上。【结论】草地贪夜蛾对大豆和玉米的取食适应和产卵选择具有一定的差异,相较于大豆,草地贪夜蛾对玉米表现出较强的选择趋向性和利用能力,在玉米-大豆“2+4”带状种植模式下,草地贪夜蛾以危害玉米为主。因此,在实际生产中,应加强对草地贪夜蛾的监测和防治工作,特别是在玉米生长的关键时期采取有效的防治措施,以降低其危害风险。

长江流域田间配置对玉米-大豆带状复合种植群体产量和气候资源利用效率的影响

【目的】探究长江流域各地区群体产量效益与光、温、水资源利用效率最优的生产单元和行比配置。【方法】在长江流域粮食主产区,以当地主栽的带状复合种植模式为主,四川与湖北地区采用春玉米夏大豆带状套作模式,湖南与江西地区采用春玉米春大豆带状间作模式,江苏地区采用鲜食玉米鲜食大豆带状套作模式,以单作玉米(MM)与单作大豆(SS)为对照,设置5个不同的玉米-大豆带状间套作田间配置:生产单元2 m行比2∶2(T1)、生产单元2.4 m行比2∶3 (T2)、生产单元2.4 m行比2∶4 (T3)、生产单元2.8 m行比2∶3 (T4)、生产单元2.8 m行比2∶4 (T5)。【结果】3年试验结果表明各地区玉米产量总体呈现随生产单元宽度增加下降的趋势,大豆产量呈现为相反趋势,群体产量呈现随生产单元宽度增加下降的趋势。不同区域玉米-大豆带状复合种植均表现出明显的间套作优势,土地当量比在不同地区之间尤以长江上游的四川、湖北生态区表现突出,最高达1.64。长江上中下游各田间配置群体产量效益与光温水资源利用均大幅高于单作大豆,在生产单元2 m,行比2∶2的田间配置下相较单作玉米,长江上游四川与湖北试验点平均经济效益分别提高了39.20%、39.34%,光温水生产效率分别提高了31.48%、19.42%、13.85%(四川)和56.90%、41.45%、42.89%(湖北),长江下游江苏试验点3年平均经济效益提高22.22%,光温水生产效率分别提高22.09%、13.16%、14.41%。长江中游湖南试验点在生产单元2.4 m,行比2∶3的田间配置下3年平均经济效益与光温水生产效率较单作玉米分别提高13.07%、13.86%、7.77%和6.45%,长江中游江西试验点在生产单元2.4 m,行比2∶4的田间配置下3年平均经济效益与光温水生产效率较单作玉米无显著差异。【结论】综合3年群体产量效益与资源利用率及主成分分析表明,长江上游(四川、湖北)与长江下游(江苏)玉米-大豆带状套作区应实行生产单元2 m,行比2∶2的田间配置,长江中游(湖南、江西)带状间作区可分别采用生产单元2.4 m,行比2∶3与生产单元2.4 m,行比2∶4的田间配置。

种植密度对北疆灌区大豆-玉米带状间作混合青贮产量和作物抗倒特性的影响

【目的】针对北疆灌区光照资源丰富但青贮种植单一的问题,利用大豆-玉米带状复合种植优势,在北疆灌区通过设计大豆-玉米不同种植密度来调控作物青贮产量,为当地青贮间作适宜密度栽培提供参考。【方法】设置3个玉米种植密度:9万株/hm^(2)(M1)、10.5万株/hm^(2)(M2)和12万株/hm^(2)(M3)。3个大豆种植密度:15万株/hm^(2)(S1)、18万株/hm^(2)(S2)和21万株/hm^(2)(S3),阐明不同密度处理下作物农艺性状、群体光合有效辐射、抗倒伏特性和青贮产量。【结果】玉米种植密度从9万株/hm^(2)增至12万株/hm^(2),茎秆穿刺强度平均降低17.30%~25.72%,倒伏率平均增加51.13%~55.27%,叶面积指数(LAI)平均增加8.00%~22.82%,光合势(LAD)平均增加10.49%~29.49%,产量呈先升后降趋势,在10.5万株/hm^(2)密度下获得最大值,大豆株高和倒伏率随玉米种植密度增加呈上升趋势,大豆冠层透光率、茎粗和抗折力呈下降趋势,LAI和LAD呈先升后降趋势。在玉米低、中和高密度处理下,大豆高密度间作与低、中密度间作相比,抗折力分别降低18.71%~29.83%、19.68%~36.94%和20.48%~31.74%,倒伏率分别增加9.77%~48.50%、9.82%~66.24%和2.25%~35.80%。随大豆种植密度增加,大豆LAI、LAD和产量增加,倒伏率显著下降。M2S3处理间作系统混合青贮产量最高,为64 981.84 kg/hm^(2),较M2S1处理增产2.81%。【结论】玉米10.5万株/hm^(2)搭配大豆21万株/hm^(2)间作种植有利于提高混合青贮产量,可为北疆灌区青贮大豆-玉米带状复合种植适宜播种密度种植提供参考依据。

宁夏引黄灌区不同带距及水肥处理对玉米大豆间作系统光合特性和产量的影响

为明晰玉米大豆间作系统对不同带距和水肥供给条件的响应特征及其效应,在宁夏引黄灌区选取玉米-大豆2∶4间作种植模式,研究带距(A)、灌溉定额(W)、施肥量(F)对玉米、大豆及间作系统的生理指标、净同化率、叶面积指数和产量的影响,为玉米大豆带状复合种植技术推广应用提供技术支持。结果显示:A对玉米生理指标的影响主要在拔节期和灌浆期(贡献率分别为75.6%~83.7%、52.4%~81.3%),W在抽穗期(贡献率为91.4%~92.5%);A对大豆生理指标的影响主要在开花期(贡献率为97.9%~99.3%),W在结荚期(贡献率为70%)。T6(A2W3F1)处理有利于玉米净同化率(NAR)和叶面积指数(LAI)升高,在试验的高水高肥对大豆LAI呈负相关。三因素对系统产量和经济效益影响显著,排序为W>A>F;A和W的3个水平对玉米产量和系统产量均有显著影响,且A2>A3>A1,W3>W2>W1,F水平对大豆产量影响不显著;各因素水平对系统经济效益贡献率为A2>A3>A1、W3>W2>W1和F1>F3>F2,A2的效益比A1高25.2%、W3比W1高32.3%、F1比F2高11.2%。

襄阳市玉米大豆带状复合种植示范研究

玉米大豆带状复合种植是近年来农业部重点推广的新模式,是落实“藏粮于技、藏粮于地”战略,保障国家粮食安全的重要举措之一。示范推广该项技术的前提是保障土地综合收益,而宜机化并尽快实现全程机械化是重要支撑。在总结襄阳市2023年实施玉米大豆复合种植过程中存在的主要问题基础上,针对问题提出了建议,希望对今后的示范应用有所帮助。

种植密度对玉米-大豆带状间作系统玉米产量性状及品质的影响

陇东黄土高原玉米种植面积大,提高玉米产量和改善品质的适宜带状间作种植密度非常重要。本文以当地玉米单作(49500株/hm^(2))为对照,设玉米低密度(45000株/hm^(2))和高密度(54000株/hm^(2))两种玉米-大豆带状间作种植密度,研究带状间作种植密度对玉米产量和品质的影响。结果表明,与玉米单作处理相比:(1)间作处理玉米穗粗和穗行数略有降低,高密度种植时玉米穗长和行粒数最高,分别达到21.2 cm和40.5粒/行;(2)高密度间作种植增加了玉米产量,显著增加了玉米地上部干物质量(20949 kg/hm^(2));(3)高密度间作种植时,玉米籽粒蛋白、脂肪及纤维含量最高,较玉米单作处理分别提高10.9%、2.53%和2.91%。主成分分析可以解释不同处理结果79.6%的差异,高密度带状间作种植对玉米的产量和品质影响更为显著。研究表明,该区域玉米-大豆带状间作种植中,玉米以54000株/hm^(2)密度种植,可提高玉米的产量和品质,适合在陇东黄土高原及类似地区推广应用。

大城县大豆玉米带状复合种植技术

推广大豆玉米带状复合种植,力争玉米单产与清种基本相当,尽可能增加大豆产量,集成创新适合大城县的大豆玉米带状复合种植技术模式,实现作物带间轮作,改良土壤结构,减少病虫发生,降低化肥农药使用量。

10种土壤处理除草剂在大豆-玉米带状复合种植田应用效果评价

为筛选适宜在大豆(Glycine max)-玉米(Zea mays)带状复合种植田使用的土壤处理除草剂,本试验选用10种药剂,进行田间小区试验,测定除草剂对杂草的防治效果及对大豆和玉米的安全性。结果表明:在推荐剂量下,精异丙甲草胺、异丙甲草胺、乙草胺、唑嘧磺草胺、扑草净、噻吩磺隆、2,4-滴异辛酯对大豆、玉米安全;二甲戊灵对大豆有轻微药害,嗪草酮、西草净对大豆和玉米均有轻微药害,药后25 d恢复正常。推荐剂量下,精异丙甲草胺、异丙甲草胺、二甲戊灵、乙草胺对狗尾草和马唐防效在90%以上;唑嘧磺草胺和扑草净对反枝苋和藜防效在90%以上,其他药剂防效较低。在大豆-玉米带状复合种植田可优先选用精异丙甲草胺、异丙甲草胺、乙草胺防治禾本科杂草,选用唑嘧磺草胺或扑草净防治阔叶杂草。

播期、密度对带状间作大豆茎叶生长及产量形成的影响

基于西南地区油菜收获后大豆-玉米带状间作种植存在的弱光环境、品种和密度筛选等问题,选择2个不同熟期的品种南夏豆25号(ND25,中晚熟,多分枝)、齐黄34(QH34,早熟,少分枝),分析播期(2021年,S1:5月17日,S2:5月27日,S3:6月6日;2022年,S1:5月10日,S2:5月25日,S3:6月9日)及密度(D1:81,000株hm^(–2),D2:101,000株hm^(–2),D3:140,000株hm^(–2),D4:171,000株hm^(–2))对带状间作大豆茎叶生长及产量形成的影响。结果表明:同一密度,随着播期的推迟,2个品种始粒期的叶面积指数逐渐减小,冠层内部透光率逐渐增加,ND25对荚的分配比率逐渐增加,倒伏率逐渐降低,QH34对荚的分配比率逐渐减少,倒伏率逐渐增加;同一播期,随着密度的增加,2个品种始粒期的叶面积指数逐渐增加,透光率逐渐减小,对荚的干物质分配比率逐渐减少,倒伏率逐渐上升。光环境及干物质分配差异对不同品种的产量影响不同,ND25同一密度不同播期间,S3>S2>S1,同一播期不同密度间,D1>D2>D3>D4,ND25品种S3播期D1密度产量最优,为1752.89 kg hm^(–2);QH34同一密度不同播期间,S1>S2>S3,同一播期不同密度间,D3>D2>D1>D4,QH34品种S1播期D3密度产量最优,为1538.64 kg hm^(–2)。因此,中晚熟品种应适当晚播,早熟品种应适当早播,多分枝品种适度稀植,少分枝品种适度密植,各品种通过播期、密度协同可提高大豆产量。

种间距对不同结瘤特性套作大豆根瘤生长及固氮潜力的影响

为充分挖掘套作大豆的固氮潜力,本试验以玉米/大豆带状套作系统为对象,研究了不同玉豆间距(30 cm、45 cm、60 cm和75 cm)下不同结瘤特性大豆品种(贡选1号、桂夏3号和南豆25号)的根瘤生长及固氮潜力差异。结果表明,与单作相比,带状套作可延缓大豆根瘤数目和鲜重峰值出现的时间:玉豆间距60 cm处理下,各品种大豆根瘤数目和鲜重显著高于其他间距处理,并在达到峰值期后高于单作大豆;品种间表现为:南豆25号>桂夏3号>贡选1号。带状套作相对于单作会降低始粒期(R5)前大豆根瘤的单株固氮潜力,但玉豆间距60 cm处理下,R5期贡选1号、桂夏3号和南豆25号的单株固氮潜力2年平均较单作提高8.53%、16.40%和13.70%。不同大豆品种根瘤侵染细胞内含物积累过程差异较大,相较单作,玉豆间距60cm处理下,R5期类菌体数量增多,其中聚-β-羟基丁酸盐颗粒(PHB)增加,以南豆25号表现最优。因此,带状套作下适宜的种间距(玉豆间距60cm)可增加R5期大豆根瘤数目和鲜重,提高大豆根瘤类菌体和PHB的数量,增强大豆根瘤的固氮潜力,以强结瘤品种南豆25号效果最好。