Effect of Component Densities on the Productivity of Soybean/Maize and Soybean/Sorghum Intercrop

Field experiments were conducted during the wet seasons of 1986 and 1987 at the Yandev Agricultural Experiment Station to investigate the effects of component density on the yield of sorghum or maize intercropped with soybean. Seed yield of the monocrops of sorghum, maize and soybean were higher than the individual components in the intercrops. Yields of component crops in the intercrop varied significantly with the components population density. The sorghum/soybean intercrops which had LER (Land Equivalent Ratio) up to 1.40 in 1986 and 1.35 in 1987 were more productive than soybean/maize intercrop with maximum LER of 1.28 and 1.34 respectively during 1986 and 1987. Similarly the ATER (Area X Time Equivalent Ratio) of sorghum/soybean was greater than in soybean/maize. However, for maximum productivity of sorghum or maize intercropped with soybean, optimum population of one component crop plus 1/2 optimum population of the companion crop is recommended depending on which of the crop is regarded as main or minor crop.     

Comparison of Drought Tolerance of Maize,Sweet Sorghum and Sorghum‐Sudangrass Hybrids

In drought‐prone environments, sweet sorghum and sorghum‐sudangrass hybrids are considered worthy alternatives to maize for biogas production. The biomass productivity of the three crops was compared by growing them side‐by‐side in a rain‐out shelter under different levels of plant available soil water (PASW) during the growing periods of 2008 to 2010 at Braunschweig, Germany. All crops were established under high levels of soil water. Thereafter, the crops either remained at the wet level (60–80 % PASW) or were subjected to moderate (40–50 % PASW) and severe drought stress (15–25 % PASW). While the above‐ground dry weight (ADW) of sweet sorghum and maize was insignificantly different under well‐watered conditions, sweet sorghum under severe drought stress produced 27 % more ADW than maize. The ADW of sorghum‐sudangrass hybrids significantly lagged behind sweet sorghum at all levels of water supply. The three crops differed markedly in their susceptibility to water shortage. Severe drought stress reduced the ADW of maize by 51 %, but only by 37 % for sweet sorghum and 35 % for sorghum‐sudangrass hybrids. The post‐harvest root dry weight (RDW) in the 0–100 cm soil layer for maize, sweet sorghum and sorghum‐sudangrass hybrids averaged 4.4, 6.1 and 2.9 t ha^?1 under wet and 1.9, 5.7 and 2.4 t ha^?1 under severe drought stress. Under these most dry conditions, the sorghum crops had relatively higher RDW and root length density (RLD) in the deeper soil layers than maize. The subsoil RDW proportion (20–100 vs. 0–20 cm) for maize, sweet sorghum and sorghum‐sudangrass hybrids amounted to 6 %, 10 % and 20 %. The higher ADM of sweet sorghum compared with maize under dry conditions is most likely attributable to the deep root penetration and high proportion of roots in the subsoil, which confers the sorghum crop a high water uptake capacity.     

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.     

不同水分条件下常规尿素和控释尿素对玉米根冠生长及产量的影响

为了进一步探讨控释尿素在玉米上的应用效果, 于2006—2007年在防雨棚中, 应用郑单958进行了池栽试验。在不同水分条件下, 比较了施用常规尿素和控释尿素后, 玉米各生育阶段的根系活力、植株生长及籽粒产量。与常规尿素(全部基施和基施+小喇叭口期追施)相比, 地上部干重、叶面积指数开花前较低, 开花后较高;成熟期籽粒产量显著高于不施氮对照和两个常规尿素处理, 生物产量显著高于不施氮对照和常规尿素全部基施处理。从籽粒产量看, 维持土壤田间最大持水量的50%时, 控释尿素处理分别比常规尿素全部基施处理和分次施处理高27.3%和12.1%;维持土壤田间最大持水量的75%时, 分别比常规尿素全部基施处理和分次施处理高17.4%和8.1%。相同氮肥处理, 土壤田间最大持水量维持75%处理比维持50%处理籽粒产量和生物产量平均分别高20.6%和17.0%, 差异均达极显著水平。与常规尿素处理相比, 控释尿素处理花前根系数量、活性和根冠比均较低, 但花后三者能维持较高水平。可见, 控释尿素对玉米生长具有明显的“前控后保”效果;控释尿素与水分对玉米产量的耦合效应高于常规尿素, 其原因是生育后期能维持较高的根系数量及活性, 促进地上部干物质积累和转移。     

覆膜方式对雨养饲用玉米生长、产量及水分利用效率的影响

为促进冀西北坝上高寒半干旱区旱地饲用玉米稳产、高产和提高水分利用效率,于2016—2017年在农业部张北农业资源与生态环境重点野外观测试验站,进行了露地平作(ck),双垄沟覆膜、微垄覆膜、土下覆膜处理对饲用玉米叶面积指数、干物质积累、土壤水分、产量和水分利用效率影响的试验研究。结果表明,在丰水年,双垄沟覆膜处理效果最好,与露地相比叶面积指数、干物质积累量、土壤蓄水量分别提高36.45%、70.24%、13.25%,产量和水分利用效率提高了67.24%和87.66%;在欠水年,土下覆膜处理效果最佳,较露地增产71.31%,水分利用效率提高81.69%。双垄沟覆膜是寒旱区提高饲用玉米产量和高效利用降水的有效技术,土下覆膜则更适用于土壤贮水丰富农田的高水效生产。     

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.     

播期对雨养旱地春玉米生长发育及水分利用的影响

为了解决陕西渭北旱塬地区玉米播种期干旱缺水造成出苗不全、不整齐,导致产量低而不稳的问题,设置6个不同播期,研究对春玉米生长发育、干物质生产、产量形成、水分利用及环境因子的影响。结果表明,随着播期的推迟,玉米的生育期明显缩短,营养生长期、营养生长与生殖生长并进期变化范围为2~19 d,生殖生长阶段则相对稳定,变化范围仅为?3~5 d。在一定的时间范围内,不同播期处理间的单株干物质生产没有明显差异,但由于受播期调整后的土壤含水量变化影响,适宜播期的玉米花后雌穗干物质积累量、籽粒产量及水分利用效率分别较早播和晚播提高4.0%~23.6%、3.9%~24.5%和6.6%~14.5%。早播影响产量的主要因素是播种期土壤含水量低而造成的出苗差,实际收获穗数不足;晚播影响产量的主要因素是生殖生长期后移,有效积温和日照时数减少造成的花后干物质积累减少、千粒重下降。适期播种可以增加田间实际收获穗数,促进雌穗花后干物质积累,提高玉米的水分利用效率。结合该区生态因素,5月4日以前适墒播种是玉米高产的有效避旱播期。研究结果可为该区春玉米抗逆避旱高产栽培提供有效的技术参考。     

垄沟种植对土壤水分变化及夏玉米生育的影响

为探讨华北地区夏玉米垄沟种植效果和适宜种植方式,在大田条件下研究了小麦收获后起垄沟播、垄作和平作3种种植方式对土壤含水量动态变化和玉米叶片水势、生育和产量的影响。结果表明,沟播处理土壤含水量明显高于垄作和平作,叶片水势、叶面积、干物质积累也高于垄作和平作,最终产量分别比垄作和平作高3.81%和11.62%。     

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.     

内蒙古黄土高原秸秆还田对玉米农田土壤水热状况及产量的影响

内蒙古清水河县地处黄土高原的边缘地带,沟壑纵横,是典型的北方干旱缺水地区。为明确秸秆翻耕还田对该区域玉米农田土壤蓄水保墒效果及产量形成特性的影响,通过连续2年的田间小区试验,探究0kg/hm ²（CK）、3 000kg/hm ²（SF1）、6 000kg/hm ²（SF2）和12 000kg/hm ²（SF3）4种秸秆还田量下玉米农田全生育期地温、土壤水分、植株生长发育、水分利用效率和产量的变化规律。结果表明：秸秆还田促进了玉米叶面积指数提高和地上部生物量的积累,2018年,SF2处理叶面积指数和地上部干物质积累量较CK分别提高13.17%和10.70%;玉米全生育期0~30cm土层土壤温度、0~80cm土层土壤含水率、生育期贮水量和农田耗水量、水分利用效率和产量均表现为SF2>SF3>SF1>CK;2018年,SF1、SF2和SF3产量分别较CK提高了8.5%、11.4%和9.3%。秸秆翻耕还田措施能够显著改善玉米农田土壤水热状况、促进植株生长、提升子粒产量和水分利用效率,其中6 000kg/hm ²还田处理效果最好,可作为节水保墒栽培模式在内蒙古黄土高原推广应用。     

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.     

拔节和抽雄期水分胁迫对春玉米生长和产量的影响

本试验设置了三种水分处理，包括CK（整个生育期供水充足）、T1（从拔节期开始控水，持续不灌水直至生育期结束）、T2（从抽雄期开始控水，持续不灌水直至生育期结束），讨论水分胁迫对玉米生长和产量的影响。结果表明：玉米株高和叶面积指数对拔节期水分胁迫T1处理比较敏感，T2处理下的影响不是很显著；水分胁迫作用下营养器官积累的干物质对籽粒的贡献率显著下降，特别是叶片和茎秆积累的产物下降明显，叶鞘的干物质积累量仅对T1处理比较敏感；水分胁迫对玉米的穗部性状影响较大，最终导致T1、T2处理较CK处理减产62.8%和37.8%；水分胁迫作用下，对产量影响大小的因子排序为穗粒数>穗长>百粒重>干物质转运率>穗粗>叶面积指数>生物量。     

Planting density and sowing proportions of maize–soybean intercrops affected competitive interactions and water-use efficiencies on the Loess Plateau,China

In field trials on the Loess Plateau, China, in 2012–13, maize (Zea mays L.) and soybean (Glycine max L.) were sole cropped and intercropped at three densities and with three sowing proportions. Maize was generally more growth efficient for biomass accumulation than soybean during the entire growth interval, as assessed using the relative efficiency index (REI_c). However, most of sowing proportion at each density displayed a trend of decreased growth with development. Throughout the growth period, the dry matter production and leaf area index (LAI) of maize increased as the plant density increased irrespective of whether it was grown as a sole crop or as an intercrop. However, the effect of increasing cropping density was less obvious for soybean. The LAI values of the sole crop treatment for both maize and soybean were greater than that of the intercropping system, indicating that the presence of maize and soybean together suppressed the respective growth of the two crops. At the final harvest, land equivalent ratios (LER) of 0.84–1.35 indicated resource complementarity in most of the studied intercrops. Complementarity was directly affected by changes in plant densities; the greatest LER were observed in 2 rows maize and 2 rows soybean intercrops at low density. The water equivalent ratio (WER), which characterized the efficiency of water resource use in intercropping, ranged from 0.84 to 1.68, indicating variability in the effect of intercropping on water-use efficiency (WUE).     

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.     

Intercropping for the Improvement of Sorghum Yield, Soil Fertility and Striga Control in the Subsistence Agriculture Region of Tigray (Northern Ethiopia)

Striga hermonthica is a major biotic constraint in the dry and less fertile areas of northern Ethiopia. Emphasis is being placed on improved cropping systems to address the interrelated problems of Striga and soil fertility decline. The potential benefits of intercropping were investigated at two sites representing different environments for crop yield improvement, soil fertility maintenance and Striga control. Ten food legume and oilseed crop species were compared in inter‐row arrangement with sorghum under non‐fertilized conditions. In most cases, there was no significant negative impact of intercropping on sorghum growth and development. Among the intercrops, two cowpea varieties – cv. TVU 1977 OD and cv. Blackeye bean – produced the highest supplemental yield of up to 329 and 623 kg ha^?1 grain and 608 and 1173 kg ha^?1 biomass at Adibakel and Sheraro respectively. Treatment differences on Striga infestation and measured soil fertility indicators were not significant. Nevertheless, valuable grain and biomass obtained from the legume intercrops, without seriously compromising sorghum yield, could offer multiple benefits as a source of protein, additional income, feeds for animals and manure in the subsistence agriculture regions of northern Ethiopia.     

覆盖对夏玉米产量及水分利用效率的影响

研究不同土壤水分状况下秸秆覆盖对夏玉米生长发育指标、产量和水分利用效率的影响。试验在防雨棚下的测坑中进行,设计了秸秆覆盖和土壤水分控制下限（占田间持水率的75%,65%和55%）两个因素,分析夏玉米生长指标、产量及水分利用效率的变化规律。结果表明,秸秆覆盖对夏玉米生长发育有促进作用,在不同的水分状况下,覆盖处理的夏玉米叶面积指数、产量和水分利用效率均优于不覆盖处理。中水分条件覆盖处理下的夏玉米产量较对照条件下的高水分夏玉米产量无显著降低,而且其水分利用效率最高。建议在夏玉米覆盖生产方式中采用中水分灌溉方式,可以达到节水高产的目的。     

山西中北部春玉米生长季土壤水分动态及对产量的影响

为了掌握土壤水分与玉米生长发育内在关系,提高土壤水分利用率,统筹调配水资源和防灾减灾提供理论依据,利用1994—2010年山西省忻州市忻府区农业气象观测站春玉米生长季0~50 cm土壤水分和玉米产量观测资料,分析了玉米生长季土壤水分变化规律及对玉米产量的影响。结果表明：春玉米生长季土壤水分年际变化振荡明显,呈多波动变化,与年降水量相关显著;一年中土壤水分变化分为水分消耗期、水分补给期和水分平稳期3个阶段;土壤水分的垂直变化明显,在20~30 cm层含水量最大,0~20 cm为多变层,20~50 cm为缓变层,雨季土壤水分变化较干季复杂;玉米拔节—乳熟期土壤贮水量与气候产量呈正相关,抽雄期是需水临界期,此时0~50 cm土壤贮水量每增加10 mm,产量增加200~250 kg/hm²。     

不同供肥条件下水分分配对旱地玉米产量的影响

以盆栽试验和田间试验研究了不同供肥条件下不同生育期水分状况对玉米产量的影响。结果表明，任何生育期的土壤干旱胁迫均会导致玉米减产，肥料供应充足时减产幅度较小；干旱胁迫越严重，肥料的这一作用越显著。无论正常供肥还是低肥，玉米对抽雄期土壤水分最敏感，防止这一时期干旱胁迫对保证玉米产量具有重要意义。拔节期是旱地玉米有限灌溉的另一个关键时期，水分的增产潜力很大，低肥时增加拔节期土壤水分供应效果更显著。玉米苗期并不耐旱，尤其是低肥时苗期干旱显著影响玉米的籽粒产量。在相对含水量45%~90%范围内，玉米产量随土壤含水量的增加而增加，但增加幅度与肥料供应和生育期有关。玉米获得最高产量的土壤水分条件与肥料供应密切相关，与正常供肥相比，低肥时所需土壤含水量较低。玉米增产的肥效大于水效，产量随肥料投入的增加显著提高，水分胁迫条件下增加肥料供应同样具有增产作用。肥料供应不足时水分的增产作用会受到限制。在现有的水资源条件下，提高肥料供应水平是旱地玉米增产的主要途径。     

Nitrogen Rates and Water Stress Effects on Production, Lipid Peroxidation and Antioxidative Enzyme Activities in Two Maize (Zea mays L.) Genotypes

Effects of nitrogen rates and water stress (WS) on production, lipid peroxidation and antioxidative enzyme activities in two maize (Zea mays L.) genotypes were assessed at different stages under two levels of water supply conditions. WS caused a significant decline in dry matter, grain yield and activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) whereas a marked rise in malondialdehyde (MDA) concentration was observed in leaves for the two genotypes. However, the responses of the two varieties to WS were different: significantly higher dry matter, grain yield and antioxidative enzyme activities and lower MDA content were observed for Shaandan 9 than Shaandan 911, therefore the former could be treated as a drought tolerance variety comparatively. A better correlation was obtained amongst dry matter, grain yield and physiological traits. The addition of nitrogen increased dry matter and grain yield as well as activities of SOD, POD and CAT to different levels and significantly decreased MDA content under WS. These effects were higher for Shaandan 911 than for Shaandan 9. Furthermore, a significant effect was found for Shaandan 911 between N rates for all traits unlike Shaandan 9. Hence, we suggest that nitrogen should be applied to a water‐sensitive variety to bring out its potential fully under drought.     

Crop Rotation to Improve Agricultural Production in Sub-Saharan Africa

A three years' trial was conducted in a farmers' field in northern Ghana to evaluate the effect of sole crops (cotton, cowpea, groundnut, soybean, and sunflower) planted once or twice on yield of the staple foods of the region, maize and sorghum. Sole cropping for only one year already resulted in significant yield increases for maize and partly for sorghum compared to the conventional cropping of mixed stands of maize–sorghum or maize–groundnut and natural fallow. Lowest yield of maize and sorghum was obtained where these cereals followed maize–sorghum (monoculture). Intercropping of maize with groundnut led to subsequent maize and sorghum yields which were similar to those obtained after maize–sorghum. After growing legumes and sunflower for one year the grain and straw yield of maize and sorghum was significantly higher in the two consecutive years than after cereal (maize–sorghum) monoculture. In this trial maize and sorghum were found to be not as tolerant to the disadvantages of monoculture or preceding cereals–legumes mixture. The results suggest that continuous intercropping with cereals under the given conditions has negative effects on soil fertility and can lead to an increase in soil-borne pests and troublesome weeds like Striga comparable to monocropped cereals.