Intercropping Maize with Climbing Beans, Cowpeas and Velvet Beans

When one of the crops is a legume, intercropping has potential to reduce fertilizer nitrogen (N) needs and increase food quality. Total dry matter (DM) and grain yields of different plant populations of intercropped maize ( Zea mays L.) and climbing beans ( Phaseolus vulgaris L.), cowpeas ( Vigna unguiculata [L.] Walp.), or velvet beans ( Mucuna pruriens [L.] DC. var utilis [Wight] Bruck.) were compared in two experiments. Maize populations were 40,400 and 50,500 plants ha⁻¹ in combination with climbing bean populations of 0, 20,200, 40,400 and 80,800 plants ha⁻¹ in Experiment 1. In the second experiment, climbing beans, cowpeas and velvet beans at 215,200 plants ha⁻¹ were intercropped with maize at 64,600 plants ha⁻¹. Climbing beans contributed up to 5% to total DM yields in the first experiment. In the second experiment legume contributions to total DM were 20% for climbing beans, 12% for cowpeas and 8% for velvet beans. Increasing populations of maize and climbing beans increased grain and DM yields. Dry matter yield of maize was lowered by intercropping. However, DM yields of the intercrop were not different to maize sole cropped. Maize/cowpeas produced more total DM than maize/climbing beans. Cowpeas increased the total yield of crude protein by over 15% without lowering total DM yield of the intercrop compared to maize alone and are promising as a legume for intercropping with maize. Climbing beans show little promise as a possible legume for intercropping with maize.     

Effect of Planting Sequence and Time, and Nitrogen on Maize Legume Intercrop Yield

Productivity of maize ( Zea mays L.) legume intercrops is determined by soil, management, and environment. Planting sequence and time and N fertilization are easily controlled management factors but their effects on intercrop yields are not well understood. Maize grown in monoculture or intercropped with polebean ( Phaseolus vulgaris L.) or cowpea ( Vigna unguiculata [L.] Warp.) was studied for two growing seasons at Morgantown, WV. Crops were seeded in the following sequences: maize before legume, both at the same time, and legume before maize. Planting times were early May or mid June. Nitrogen was applied at 0 or 160 kg ha⁻¹. Maize grain and forage, legume grain and forage, and total forage production were determined on a dry matter basis. Intercropping (average of all treatments) reduced maize grain and forage yields compared to maize in monoculture but had no effect on total forage production. However, total forage production was greatest when the seeding sequence was maize intercropped at the same time or before cowpea. Cowpea never produced grain, but forage production was almost double that of polebean. Maize produced most forage when seeded before the legumes, and the legumes produced most forage when seeded before maize. Early planting increased maize production and decreased legume production. Nitrogen increased maize grain, maize forage, and total forage yields but had not effect on legume forage production. It is concluded that maize/legume intercrops show promise for increasing forage production in temperate areas and more research on planting times and densities, weed control, harvesting and management is needed.     

The Effects of Intercrop Spacing Patterns on the Silage Yield of Maize and Soybean

The effects of intercrop spacing patterns on the silage yields of both maize (lea mays L.) and soybean (Glycine max [L.] Merr.) were examined from 1985 to 1987. Dwarf maize was intercropped with nonnodulatmg or nodulating soybean in the spacing patterns, S_40same (two crops in the same row, 40 cm row width) and S_20ait or S_40ak (two crops in alternate rows, 20 cm or 40 cm row width, respectively). Tall maize was intercropped with nodulating soybean in S_40sames S_40alt and S_40pair (maize in 40 cm paired rows, soybean rows 20 cm outside each maize row and 80 cm from the next set of four rows) at 0 or 60 kg N ha⁻¹ and at population densities of 67% maize: 67% soybean or 50 % maize: 50% soybean. Maize and soybean were also intercropped and stripcropped on a farm-scale. The only difference between intercrops arranged in the same rows versus those in alternate rows was that the average soybean protein yields were higher in S_40same than in S_40alt. In 1986, the S_40alt maize-soybean intercrops produced higher maize yields, total biomass yields and Land Equivalent Ratios (LERs) than in S_40pirs, and in 1987, these responses were higher in intercrops than in stripcrops. In 1986, at 0 kg N ha⁻¹, the soybean biomass and protein yields were lower in S_40alt, than in S_40pairs and in 1987, these responses were lower in intercrops than in stripcrops.     

玉米–大豆带状套作行距配置对作物生物量、根系形态及产量的影响

空间配置是影响间作套种作物生长和产量构成的关键因素之一。本研究固定玉米–大豆套作带宽200 cm,玉米采用宽窄行种植,设置4个玉米窄行行距为20 cm(A1)、40 cm(A2)、60 cm(A3)和80 cm(A4)套作处理,2个玉米和大豆净作对照处理,研究行距配置对套作系统中玉米和大豆生物量、根系及产量的影响。结果表明,套作大豆冠层光合有效辐射和红光/远红光比值均低于净作,且随着玉米窄行的增加而降低。套作系统中大豆地上地下生物量、总根长、根表面积和根体积从第三节龄期(V3)到盛花期(R2)逐渐增加,但随着玉米窄行的增加而降低。套作玉米地上地下生物量从抽雄期到成熟期逐渐增加,根体积却逐渐降低,但这些参数随玉米窄行的变宽而增加。玉米和大豆在带状套作系统中产量均低于净作,且随玉米窄行的变宽,玉米产量逐渐增加,2012和2013两年最大值平均为6181 kg hm–2,而大豆产量逐渐降低,两年最大值平均为1434 kg hm–2,产量变化与有效株数和粒数变化密切相关。此外,玉米–大豆带状套作群体土地当量比(LER)大于1.3,最大值出现在A2处理,分别为1.59(2012年)和1.61(2013年),且最大经济收益也出现在A2处理(2年每公顷平均收益为1.93万元)。因此,合理的行距配置对玉米–大豆带状套作系统中作物的生长、产量构成和群体效益具有重要的作用。     

Effect of Planting Geometry on the Growth and Yield Performance of Maize Intercropped with Rice

A field experiment with maize and rice planted under four planting configurations in an intercropping system was conducted to evaluate the plant competition effects on the performance of component crops. Intercropping substantially reduced grain yields of both rice and maize. Rice yield was generally low giving monocrop yield of 1,084 kg/ha. Intercropped rice ranged between 179 kg/ha and 615 kg/ha depending on maize planting arrangement. Monocrop maize yielded highest in square planting (3,617 kg/ha) and lowest in skip-row (2,600 kg/ha) planting, but planting geometry did not influence intercropped maize yield. Monocrop maize outyielded the combined yield of component crops suggesting no yield advantage through rice-maize intercropping.     

Effect of Okra Planting Density and Spatial Arrangement in Intercrop with Maize on the Growth and Yield of the Component Species

The effects of three okra planting densities (28 000; 56 000 and 111 000 plants ha¹) intercropped within or between maize rows were investigated in two field trials during the 1990 and 1991 wet seasons at Nsukka. The plant height and the leaf area index (LAI) increased as the planting density increased in sole or intercropped okra while the number of branches per plant decreased with increasing okra planting density. The height of maize plants also increased as okra planting density increased but the LAI decreased. Intercropping reduced the yield and yield components (number and weight of pods per plant) of okra and maize (number of cobs, cob length and 100-grain weight). Increasing okra planting density reduced the sole and the intercropped okra and also the maize intercrop yield by reducing the number of pods and grains as well as the pod and grain size, respectively. Assessment of the productivity ofthe mixtures showed that the highest yield advantage (35%) of growing okra and maize together was obtained at 28000 okra plants ha¹ while the highest monetary return was realized at the highest okra planting density of 111000 plants ha¹ intercropped between maize rows. The patterns of row arrangement did not have effect on the growth, yield and yield components of the mixtures.     

施氮方式对玉米-大豆套作体系中作物产量及玉米籽粒灌浆特性的影响

氮肥的过量施用和低效利用, 造成资源浪费和环境污染, 不利于农业的可持续发展。为了减少氮肥的投入量, 发挥氮肥的增产效益, 本研究对玉米-大豆套作模式的施氮量和施肥距离进行优化调整。通过两年田间试验, 探讨了减氮36% (RN36%)、减氮18% (RN18%)和习惯施氮(CN) 3种施氮水平和距离窄行玉米0 cm (D1)、15 cm (D2)、30 cm (D3)、45 cm (D4) 4种施肥距离对作物产量和玉米花后干物质积累与转运、籽粒灌浆特征的影响。结果表明, 与习惯施氮相比, 减氮18%处理的玉米花后干物质转移量、转移率及对籽粒的贡献率分别提高了22.65%、18.75%和15.90%, 籽粒平均灌浆速率和最大灌浆速率提高了9.79%和10.76%; 玉米、大豆产量及系统周年产量提高了4.95%、7.07%和5.35%; 各施肥距离间, 以距离窄行玉米15~30 cm的施肥效果最佳。减氮18%时, D2处理下玉米的平均灌浆速率、最大灌浆速率、穗粒数及百粒重比玉米常规穴施(D1)处理分别提高了10.32%、10.92%、9.08%和4.75%; 玉米、大豆产量和系统总产最高。玉米-大豆套作体系下, 减氮18%和距离窄行玉米15~30 cm施肥有利于增加玉米花后干物质的积累, 促进干物质向籽粒中转运, 增大灌浆速率, 增加百粒重和穗粒数, 提高玉米产量和大豆产量, 以实现系统周年作物增产。     

中单808和丹豆14间作系统生理生态指标及产量的比较分析

通过对中单808(玉米)、丹豆14(大豆)4∶2和4∶4型间作系统在灌浆期生理生态指标、产量及主要农艺性状的分析,表明间作群体系统中玉米内部各项指标得到改善,农艺性状优化,产量显著增加;而间作大豆产量和农艺性状有不同程度下降,但随着大豆行比的增加逐渐得到改善。经产量差异比较和经济效应分析,认为4∶4型间作模式群体正负迭加后的优势大于4∶2型间作和清种模式,为发挥玉米高产潜能,提高大豆产量,以玉米大豆4∶4型间作模式较好。     

利用SPSS实现玉米杂交种主要农艺性状与产量的相关和通径分析

以黑龙江省农业科学院玉米研究所自育的74个玉米杂交材料为研究对象,运用SPSS 18.0对玉米杂交种产量与主要农艺性状中的生育期、株高、穗位、穗长、穗粗、秃尖长、穗行数、行粒数、粒宽、粒厚、百粒重、容重、出子率关系进行逐步回归分析和通径分析,计算主要农艺性状对杂交种产量的决策系数。结果表明,出子率、百粒重、生育期、穗长和穗行数是影响玉米产量的主要正因素。     

Yields and Land-Use Efficiency of Maize-Cowpea Crop Rotation in Comparison to Mixed and Monocropping on an Alfisol in Northern Ghana

Results reported in the literature with regard to productivity of intercropping systems in comparison to sole cropping are very inconsistent. A field experiment was therefore conducted in the northern part of the Guinea Savanna in Ghana to compare the productivity of maize/cowpea mixed cropping, maize/cowpea relay intercropping with maize/cowpea rotation and maize monocropping over a 4-year period. The treatments included two levels of nitrogen (0 and 80 kg of N ha⁻¹ y ⁻¹ as urea) and two levels of phosphorus application (0 and 60 kg of P ha⁻¹ y⁻¹ as Volta phosphate rock). At all levels of N and P application, maize yields of the intercropping systems, especially of maize/cowpea mixed cropping, were significantly lower than in sole cropping. Highest maize yields were obtained in maize/cowpea rotation, which in contrast to the other cropping systems did not show any reductions in yields over years. Cowpea yields were generally less affected by the cropping system, but were notably depressed when cowpea was relay-intercropped with maize. In treatments without fertilizer application (N and P) Land Equivalent Ratios (LER) and Area x Time Equivalency Ratios (ATER) generally indicated lower productivity of the intercropping systems as compared to sole cropping, with the maize/cowpea rotation showing the highest productivity. Conversely, fertilizer application resulted in higher productivity of the intercropping systems over the 4-year period. Productivity on the basis of ATER was generally lowest in maize/cowpea relay-intercropping as a consequence of the long time of land occupation. All of the parameters indicate low productivity of maize monocropping, clearly demonstrating that crop sequence as well as fertilizer application must be considered as important for maintaining high production levels at this site.     

Yield and Yield Components from Intercropping Improved Bush Bean Cultivars with Maize

Bush bean ( Phaseolus vulgaris L.) is widely intercropped with maize ( Zea mays L.) in North-west Spain. Little information is available on the relative performance of elite bush bean cultivars when intercropped or on the effect of bush bean on performance of the maize crop. This two-environment study presents the interactions between improved bush bean cultivars and maize on yield and yield components. Eight treatments (four bean/maize intercrops and four sole crops, two of bean and two of maize) were tested using a randomized complete block design with four replications in two environments. Bean and maize were planted simultaneously in alternate rows when intercropped. Significant treatment differences were observed for bean and maize moisture, pod and cob percentage, bean and maize yield, ears per plant and ear length. Location effects were significant for bean and maize moisture and pod percentage. Significant treatment by location interactions occurred for pod percentage and ear length. Intercropping reduced yield by between 40 and 60 % for bush bean cultivars, and by 45 % for both maize cultivars. Mean yields were used to calculate the land equivalent ratio (LER), which averaged 1.01 in Pontevedra but 0.93 in La Coruña. Intercropping of bush bean with maize did not make better use of land than conventional sole cropping under these environmental conditions. It is suggested that this was probably due to the amount and distribution of rain in relation to crop growth. Approaches that might be expected to result in improved land usage are presented.     

Direct and Residual Contributions of Symbiotic Nitrogen Fixation by Legumes to the Yield and Nitrogen Uptake of Maize (Zea mays L.) in the Nigerian Savannah

Field experiments were conducted to determine the direct and residual contributions of legumes to the yield and nitrogen (N) uptake of maize during the wet seasons of 1994 and 1995 at the University Farm, Abubakar Tafawa Balewa University, Bauchi, Nigeria, located in the Northern Guinea savannah of Nigeria. Nodulating soybean, lablab, green gram and black gram contributed to the yield and N uptake of maize either intercropped with the legumes or grown after legumes as a sole crop. Direct transfer of N from the nodulating soybean, lablab, green gram and black gram to the intercropped maize was 24.9–28.1, 23.8–29.2, 19.7–22.1 and 18.4–18.6 kg N ha^–1, respectively. However, the transfer of residual N from these legumes to the succeeding maize crop was 18.4–20.0, 19.5–29.9, 12.0–13.7 and 9.3–10.3 kg N ha^–1, respectively. Four years of continuous lablab cropping resulted in yields and N uptake of the succeeding maize crop grown without fertilizer N that were comparable to the yields and N uptake of the succeeding maize crop supplied with 40–45 kg N ha^–1 and grown after 4 years of continuous sorghum cropping. It may therefore be concluded that nodulating soybean, lablab, green gram and black gram may be either intercropped or grown in rotation with cereals in order to economize the use of fertilizer N for maize production in the Nigerian savannah.     

麦季氮肥运筹对冬小麦–夏玉米种植体系物质生产及氮肥利用的影响

2009-2011年在山东临沂冬小麦-夏玉米生产田,探讨了麦季施氮水平和施氮时期对两季作物干物质积累与分配、籽粒产量、氮肥农学利用率和氮肥偏生产力的影响。施氮量设4个处理,分别是0 (N0)、168.75 (N1)、225 (N2)和281.25 kg hm^-2 (N3);氮肥追施时期设2个处理,分别为拔节期(S1)和拔节期+开花期(S2)。在S1条件下,冬小麦和夏玉米的籽粒干物质积累量及夏玉米和周年生物产量均表现为N3>N2>N1,冬小麦和夏玉米的籽粒产量N2和N3处理间无显著差异;氮肥农学利用率和氮肥偏生产力在麦季随施氮量增加显著降低,而在玉米季则逐渐升高,但玉米季氮肥偏生产力N3与N2处理间无显著差异。S2条件下麦季施氮量由N2处理增加25% (N3),冬小麦和夏玉米籽粒干物质积累量、生物产量和籽粒产量无显著变化,氮肥农学利用率和氮肥偏生产力在麦季显著降低、在玉米季无显著变化。与S1相比,S2有利于提高N1和N2条件下冬小麦籽粒与营养器官的干物质积累量、生物产量、籽粒产量和氮肥农学利用率及氮肥偏生产力,但对N3条件下的这些指标无显著影响;而在玉米季,3个施氮量水平下夏玉米的各项指标均显著升高。综合周年生物产量、籽粒产量和氮肥农学利用率及氮肥偏生产力结果,麦季总施氮量225 kg hm^-2及拔节期+开花期追氮是本试验条件和种植模式下的最佳麦季氮肥运筹模式。     

玉/豆和玉/薯模式下玉米氮素吸收利用差异及氮肥调控效应

研究西南地区玉米主要2种套作模式下氮素吸收利用差异及氮肥调控效应, 为氮素高效利用提供科学依据。在四川2个玉米主产区, 通过连续4年的大田试验, 对比研究了玉/豆和玉/薯模式下玉米氮素吸收利用差异和不同供氮水平对玉米氮素吸收的调控效应。结果表明, 玉/豆模式下玉米收获期植株中的氮素积累2个试验点平均较玉/薯模式增加7.11%, 氮收获指数增加2.00%左右, 氮素吸收效率增加7.83%, 成熟期籽粒中氮素的分配比例增加1.76%, 而叶、茎鞘中氮素的分配比例分别减少5.85%和2.75%。分带轮作后, 由于不同前茬对土壤养分影响不同, 再加上套作优势, 玉/豆模式下玉米在生长前期就表现出明显的优势, 到收获期植株氮素积累2个试验点平均较玉/薯增加11.85%, 氮素吸收效率增加11.84%。在玉米氮素积累关键时期, 玉/豆模式在低氮处理下玉米植株氮素的积累量显著高于玉/薯模式相同施氮处理, 而在高氮处理下2种模式间差异不大或者表现相反, 氮肥偏生产力、氮素农艺效率和氮肥利用率也有相似的结果; 玉/豆模式在180 kg hm^-2施氮量下较其他处理显著提高了玉米氮素农学利用率、氮素吸收利用率和籽粒中氮素的分配量, 玉/薯模式下玉米氮素农学利用率和氮肥利用效率, 在180~270 kg hm^-2施氮量处理下较高; 花后氮素同化量玉/豆模式显著高于玉/薯; 2种模式均以施纯氮180~270 kg hm^-2处理有利于氮素转运和花后氮素同化量积累。     

Evaluation of yield stability of cowpea under sole and intercrop management in Nigeria

Summary Nine cowpea (Vigna unguiculata (L.) Walp.) breeding lines were grown in 13 experiments under sole crop and intercrop management, with and without insecticide application, in Nigeria. Cowpea was intercropped with cassava (Manihot esculenta Cranz), maize (Zea mays L.) and maize-cassava in the forest zone and with sorghum (Sorghum bicolor Moench.) and millet (Pennisetum glaucum (L.) R.Br.) in the savanna zone. Line by cropping system interactions were significant in 5 of 13 experiments and line by insecticide treatment interactions were significant in 2 of 13 experiments. Cowpea yield was severely depressed in intercropped plots and in plots to which no insecticide was applied. Among-environment variation in cowpea yield was greater when no insecticide was applied. Within each management treatment, the yield performance and stability of the cowpea lines was examined. Stability was assessed both by examining among-environment coefficients of variation and by regression analysis. Several of the breeding lines evaluated appeared promising under different levels of management and in a diversity of environments.     

重庆市直辖后普通玉米杂交种籽粒产量及相关性状的育种进展

摘 要：【研究目的】为分析重庆市直辖以来自育玉米杂交种籽粒产量和相关性状的主要进展,了解该市玉米育种的主要发展趋势。【方法】以该市1997~2009年玉米区试汇总资料,采用“区试对照法”分析了自育普通玉米杂交种籽粒产量及相关性状的遗传增益。【结果】重庆市普通玉米杂交育种自直辖以来,在不断提高对照品种产量门槛的情况下,参试品种籽粒产量仍在显著增加,同直辖初期对照品种比较,平丘组平均每年提高2.83%,山区组平均每年提高2.01%。与籽粒产量相关的性状的遗传改良效果平丘组品种以穗行数和百粒重最好,生育期无甚变化,其余性状波动性较大;山区组品种以穗长、穗行数和行粒数较好,其余性状波动性也大。【结论】在当前和今后一段时期内,重庆市普通玉米杂交育种策略应在稳定生育期和株高、适度增加穗长和穗行数的前提下,主攻行粒数和百粒重。关键词：玉米;对照品种;参试种;籽粒产量;遗传改良     

The intercropping common bean with maize improves the rhizobial efficiency,resource use and grain yield under low phosphorus availability

In order to better understand how mixed crop cultures mitigate stressful conditions, this study aims to highlight the beneficial effect of the intercropping legume-cereal in enhancing soil phosphorus (P) availability for plant growth and productivity in a P-deficient soil of a northern Algerian agroecosystem. To address this question, common bean (Phaseolus vulgaris L. cv. El Djadida) and maize (Zea mays L. cv. Filou), were grown as sole- and inter-crops in two experimental sites; S1 (P-deficient) and S2 (P-sufficient) during two growing seasons (2011 and 2012). Growth, nodulation and grain yield were assessed and correlated with the rhizosphere soil P availability. Results showed that P availability significantly increased in the rhizosphere of both species, especially in intercropping under the P-deficient soil conditions. This increase was associated with high efficiency in use of the rhizobial symbiosis (high correlation between plant biomass and nodulation), plant growth and resource (nitrogen (N) and P) use efficiency as indicated by higher land equivalent ratio (LER > 1) and N nutrition index (for maize) in intercropping over sole cropping treatments. Moreover, the rhizosphere P availability and nodule biomass were positively correlated (r² = 0.71, p < 0.01 and r² = 0.62, p < 0.01) in the intercropped common bean grown in the P-deficient soil during 2011 and 2012. The increased P availability presumably improved biomass and grain yield in intercropping, though it mainly enhanced grain yield in intercropped maize. Our findings suggest that modification in the intercropped common bean rhizosphere-induced parameters facilitated P uptake, plant biomass and grain yield for the intercropped maize under P-deficiency conditions.     

Growth and Yields of Intercropped Sorghum and Sunflower (Helianthus annuus L.) in Semi-arid Nigeria

Effect of five planting patterns on the growth, yield and yield components of intercropped sunflower and sorghum was studied during 1989–90 planting seasons at University of Maiduguri, Nigeria. Generally, intercropping depressed the performance of sorghum more than sunflower. Sorghum plants grown in alternate hills with sunflower had the shortest stems, the least dry matter and total seed yields per hectare, while the highest dry matter and seed yields were obtained from sorghum planted in five alternating rows with sunflower. Similarly, in sunflower, plants grown in five alternating rows with sorghum had the highest yields compared with other planting patterns, but there were no significant differences in the dry matter and total seed yields of sorghum and sunflower intercropped in three and five alternating rows. Light transmission, leaf area index and yields of both crops followed similar trends under the various planting patterns. Interplanting in five alternating rows that allowed the highest leaf area also allowed the lowest light transmission and produced the highest yields. Land use efficiency was highly improved under three and five rows interplanting by 52 and 74 % respectively.     

The Effect of Intercropping Lablab purpureus L. with Sorghum on Yield and Chemical Composition of Fodder

In two years the growth and composition of mixtures of sorghum with Lablab purpureus as strips, paired rows and alternate rows were compared with those of sorghum and lablab monocrops. In the first year, when sowing did not occur until 7 August, the sorghum yields were low in the monocrop and even less in the mixed crops. Lablab yield was also reduced in mixtures compared with the monocrop, but total forage yield was greater for the mixed crops compared with sorghum alone. Of the mixed cropping systems, a reduction in the yield of lablab plants and in the phosphorus and potassium content of shed lablab leaves in paired rows suggested that there was more competition for nutrients between lablab plants grown in this treatment. In the second year, earlier sowing increased sorghum growth at the expense of lablab yield in the mixed cropping systems, with the result that total forage yield was not increased when sorghum was intercropped with lablab. However, the crude protein content of sorghum stems and leaf yield were increased in mixed crops, particularly in paired and alternate rows rather than strips, demonstrating that close configuration of the legume and cereal are necessary for the cereal to obtain most benefit from nitrogen fixed by the legume. It is concluded that, when conditions are favourable for rapid sorghum and lablab growth, the sorghum will benefit more when it is grown in paired rows with lablab rather than in strips. However, the close spacing normally adopted for paired rows may encourage competition between lablab plants and increase the requirements for phosphorus and potassium fertilizer.     

间作小麦光合性能对地上地下互作强度的响应

本研究旨在探讨地上地下互作强度对间作小麦光合性能的影响,为进一步揭示间作体系作物产量优势的光合机制提供依据。2015—2017年连续3年在河西绿洲灌区进行田间试验,以小麦间作玉米为研究对象,设置地下部3种互作强度:根系不分隔(完全地下互作处理, W/M)、300目尼龙网分隔(部分地下互作处理, NW/M)和0.12 mm塑料布分隔(无地下互作处理,PW/M),以及地上部高、低玉米密度(M1、M2)2种互作强度,同时设置相应单作处理。结果表明,小麦间作玉米共生前期和后期完全地下互作处理促使小麦净光合速率(P_n)显著提高,且共生后期玉米密度的提高促使完全地下互作效应增强,进一步提高了小麦P_n。小麦间作玉米共生前、中和后期,完全地下互作处理可显著提高小麦叶片气孔导度(G_s)、胞间CO_2浓度(Ci),且玉米密度提高对共生前期完全地下互作处理和部分地下互作处理小麦Gs的增加起到促进作用。在共生前期、后期完全地下互作和部分地下互作处理保持了较低的Tr。间作完全地下互作处理有助于小麦叶日积(LAD)的增加,且随着生育进程的推进,提高比率越大。完全地下互作处理使共生中期间作小麦叶片相对叶绿素含量值(SPAD)显著增加,有利于光合强度的提高。间作小麦具有显著的增产效应,完全地下互作处理中小麦籽粒产量达到相应单作产量的76.8%,具有显著提高间作群体籽粒产量的优势,且地上部互作强度增强有利于完全地下互作处理正效应的发挥。地上地下互作强度是影响间作小麦光合性能的重要因素之一,在生产实践中可通过调节地上地下互作强度的强弱来优化低位作物光合性能。