Xanthium Suppression Under Maize||Sunflower Intercropping System

Weed control is one of the major constraint factors in crop production around the world. Field experiments were conducted during 2008-2009 under intercropping systems involving alfalfa （Medicago sativa L.）, sweet potato （lpomoea batatas [L.] Lain.）, peanut （Arachis hypogaea L.）, and sunflower （Helianthus annuus L.） in maize （Zea mays L.） without any weeds control methods taken. The results demonstrate that maizellsunflower is most effective on weed suppression and that it also has a more competitively inhibitory effect on Xanthium compared with the other patterns by evaluating the Xanthium density and dry weight under different intercropping systems with maize. Maizellpeanut, maizellalfalfa and maizel]sweet potato intercrops have no apparent inhibitory effect on weeds. To further investigate the effect of maize]lsunflower on weed control, indoor pot experiments were conducted by determining the effect of extractions on germination rate （GR）, root vigor, MDA （malondialdehyde）, SOD （superoxide dismutase） and POD （peroxidase） content of Xanthium. The results better prove that maizellsunflower extractions have more significant inhibitory effect on GR and young root vigor of Xanthium than maize monocrop extractions.

Competitiveness and Profitability of Intercropping Sunflower with Peanut under Different Irrigation Water Levels and Potassium Fertilizer Rates

A two-year study was carried out at Ismailia Agricultural Research Station, Egypt during 2016 and 2017 summer seasons to evaluate competitive effects of intercropping sunflower and peanut under different drip irrigation water amounts and K fertilizer rates for increasing farmer profitability. Three irrigation amounts (70%, 100% and 120% ETo), three K fertilizer levels (57, 86 and 114 K2O kg/ha) and four intercropping patterns of sunflower and peanut (different spatial arrangements) were implemented. The experimental design was strip split plot with three replications. The results showed that there were no significant differences between 100% and 120% ETo on most of yield traits of the intercrops. The highest K fertilizer level had the highest values of most yield traits of the intercrops. The highest values of peanut and sunflower traits were obtained from intercropping sunflower with peanut, where peanut seeds were sown on both sides of all the raised beds, sunflower seeds were sown on one row above the raised beds and the following bed was left without intercropping (P1). Thus, to attain the highest yield of intercrops and water equivalent ratio (WER), the lowest competitive pressure and the highest farmer profitability, 120% ETo, 114 K2O kg/ha and P1 intercropping pattern should be implemented. This research found that the result of competitiveness was consistent with the result of profitability.

Study on Yield Potential of Autumn Potato/Rapeseed Intercropping System in Rice Field

In order to expIore the yield potential, regional adaptabiIity and key cuItiva-tion techniques of autumn potato/rapeseed intercropping system, and analyze its benefit performance and popuIarization value, the contrast experiments of Iarge re-gion were conducted in Yongchuan and Kalxian of Chongqing city from 2011 to 2012. The resuIts showed that the benefit increasing effect was significant because autumn potato/rapeseed intercropping patterns couId galn more one season potato in rice-rapeseed rotation area. The average yield of autumn potato and rapeseed in two test points were 13 567.35 and 2 663.25 kg/hm2 respectiveIy, and the total out-put value and net income reached to 38 773.05 yuan/hm2 and 15 772.5 yuan/hm2 respectiveIy, and cash income attalned 38 773.05 yuan/hm2, and net income reached 23 000.55 yuan/hm2, and the increased income was 17 221.8 yuan/hm2 and it increased by 310.3% comparing with rapeseed of soIe cropping. Therefore, the autumn potato/rapeseed intercropping in rice field is a new efficient cuItivation technique with very significant ecoIogical and economic benefit.

Potato/Maize intercropping reduces infestation of potato tuber moth, Phthorimaea operculella(Zeller) by the enhancement of natural enemies

The potato tuber moth(PTM),Phthorimaea operculella(Zeller),is one of the most economically significant insect pests for potato in both field and storage worldwide.To evaluate the infestation,reduction of potato yield and the control efficacy for PTM,field tests were conducted in two seasons by intercropping of potato as the host plant with maize as a non-host plant of PTM.Three intercropping patterns were tested,which were 2 rows of potatoes with either 2,3,or 4 rows of maize(abbreviated 2 P:2 M,2 P:3 M,and 2 P:4 M),and the monocropped potato as the control,2 rows of potatoes,without maize,(abbreviated 2 P:0 M).Results showed that the population and infestation of PTM in the 2 P:3 M intercropping pattern was significantly lower than those in 2 P:2 M,2 P:4 M and the monocropping pattern of 2 P:0 M,due to the enhancement of natural enemies.Cumulative mines and tunneling in potato leaves in 2 P:3 M intercropping were significantly lower than those in 2 P:2 M and 2 P:4 M patterns.The population of parasitoids and the parasitism rate of PTM in intercropping pattern of 2 P:3 M were significantly higher than that in intercropping pattern of 2 P:2 M,2 P:4 M and monocropping pattern of 2 P:0 M.We conclude that the potato intercropped with maize reduced the adult and larva populations,and reduced the damage from PTM by enhancing the number of parasitoids and the level of parasitism.The greatest population density of parasitoids and parasitism rate were in the intercropping pattern of 2 rows of potatoes with 3 rows of maize.These data indicate that the host/non-host intercropping patterns can be used as a biological control tactic against PTM by enhancing the density of natural enemies in the agro-ecosystems.

Synergistic effects of vegetation layers of maize and potato intercropping on soil erosion on sloping land in Yunnan Province, China

Intercropping, as an overyielding system, can decrease soil erosion on sloping land through the presence of dense canopy covers. However, the structure mechanism in canopy is still unclear. We conducted a two-year field experiment on runoff plots, exploring whether the interaction between vegetation layers reduce soil erosion in maize and potato intercropping systems. The maize, potato, and weed layers in the intercropping system were removed by a single layer, two layers and three layers, respectively(total of 8 treatments including all layers removed as the control). Then, throughfall, runoff and sediment were measured at the plot and row scale on a weekly basis. Based on the difference between each treatment and the control, we calculated and found a relative reduction of runoff and sediment by any combination of the two vegetation layers greater than the sum of each single layer. In 2016 and 2017, the highest relative reduction of runoff reached 15.65% and 46.73%, respectively. Sediment loss decreased by 33.96% and 42.77%, respectively. Moreover, runoffand sediment reduced by the combination of all vegetation layers(no layers removed) was also larger than the sum of that by each single layer. In 2016 and 2017, the highest relative reduction of runoff reached 7.32% and 3.48%, respectively. So, there were synergistic effects among multi-level(two or three layers) vegetation layers in terms of decreasing soil erosion on sloping land. Maize redistributes more throughfall at the maize intra-specific row and the maize and potato inter-specific, which is favorable for the synergistic effect of reducing soil erosion. This finding shows an important mechanism of maize and potato intercropping for soil and water conservation, and may promote the application of diverse cropping systems for sustainable agriculture in mountainous areas.

Effects of Sweet Potato Rotation and Intercropping on the Microbial Community of Rhizosphere Soil

To reveal the response mechanism of soil microbial community in different planting systems of sweet potato,the effects of rotation and intercropping on microbial community structure and carbon source utilization capacities of sweet potato rhizosphere soil were studied by using phospholipid fatty acid(PLFA)and ecological board(BIOLOG ECO)through field positioning experiments.In this study,three treatments were sweet potato continuous cropping,sweet potato-wheat rotation,and sweet potato-corn intercropping.The main results showed that compared with the sweet potato continuous cropping treatment,sweet potato rotation and intercropping changed the PLFA biomass of soil microorganisms;the contents of bacteria increased by 21.82%and 38.77%,respectively(P<0.05);the contents of actinomycetes increased by 6.98%and 12.77%,and the biomass of Gram-positive bacteria increased by 28.60%and 63.44%,respectively;and the biomass of Gram-negative bacteria increased by 18.21%and 22.29%,and the fungal contents decreased by 16.60%and 13.03%,respectively.With the extension of culture time,the average well color development(AWCD value)of sweet potato-corn intercropping was significantly higher than other two treatments.The utilization capacities of carboxylic acid compounds,polymers,carbohydrates,amino acids,and amines in the sweet potato-corn intercropping treatment were significantly increased by 17.28%,14.67%,54.17%,36.62%,and 20.00%,respectively,compared with the sweet potato continuous cropping treatment.The results of the multivariate analysis(RDA)showed that the changes of soil microbial community structure and functional diversity were controlled by many factors,and the soil available potassium and total nitrogen were the main driving factors.However,sweet potato-wheat rotation and sweet potato-corn intercropping could optimize the soil microbial community structure and enhance the microbial functional diversity,and the effect of sweet potato-corn intercropping treatment was better.

Production Mode and Economic Benefit of Improved No-tillage Intercropping with Potato in New Mode Citrus Orchard

[Objectives]In terms of increasing the utilization of land in agriculture and the per unit area yield,intercropping is the most popular farming method.[Methods]Based on the climate and soil conditions in Zhaoqing,this experiment explored the improved mode of no-tillage intercropping winter potato with citrus in the new high-ridge,wide-row and dense-plant cultivation mode citrus orchard.Taking the conventional tillage and film-mulched intercropping as the control,it studied the adaptability of intercropping,evaluated the quality,and analyzed its economic benefits.[Results]The early emergence rate of improved no-tillage intercropping cultivation was slightly higher than that of conventional tillage and film-mulched intercropping,but the difference of final emergence rate was not significant,indicating that improved no-tillage intercropping cultivation could provide excellent potato emergence environment.Under the conventional tillage and improved no-tillage intercropping cultivation mode,the change trend of the potato's plant height,main stem thickness,crown diameter and number of leaflet is the same.The change rule of the crown diameter of the film-mulched intercropping cultivation method is similar to that of the plant height,both have a large increase in the late growth stage.The potato yield of improved no-tillage intercropping cultivation were 22747.5 kg/ha,and the proportions of potatoes of each grade were 11.85%,35.61%,37.63%and 14.91%,respectively.The content of dry matter,Vc,soluble protein,starch and amino acid in the main nutrients of the potato under the improved no-tillage intercropping mode is not significantly different from that of the film-mulched intercropping cultivation.The changing trend of reducing sugar content showed that the reducing sugar content of no-tillage intercropping cultivation was the highest(0.466%).Through evaluating the eating characteristics of potatoes from the flavor,taste,texture and appearance after chewing,the three cultivation methods have little difference.In the no-tillage intercropping cultivation technology,the growth of potatoes consumes part of the nutrients in the soil between the rows of the citrus orchard,but it does not exerts a significant impact on the surrounding citrus trees.Compared with the film-mulched intercropping cultivation,the improved no-tillage intercropping cultivation method does not require the expense of mulched,the cost of fertilizer is low,and labor costs are saved,so a net income of 27075 yuan/ha can be obtained.[Conclusions]From the perspective of orchard intercropping,it has achieved the effect of improving soil utilization and increasing output without reducing the edible quality of potatoes.

Utilization of Agricultural Climatic Resources under the Spring Maize-Spring Potato Intercropping Pattern in Pengzhou City

According to the meteorological requirements of maize and potato,using the data of meteorological observations and soil moisture of Pengzhou City,the agricultural climatic resources of spring maize and spring potato planting and the advantages of agricultural climatic resources of their intercropping were analyzed. The suitable sowing dates for spring maize and spring potato are late March to early April,early February to early March,respectively. During the growth period,the heat resources are abundant,the soil moisture is sufficient,the precipitation and overall distribution are suitable,and the sunshine is still sufficient,which can meet the needs of each growth period. The overall configuration of agricultural meteorological resources is coordinated,which is suitable for the planting of the two. Spring maize-spring potato intercropping can make the most of land,time and space,improve light and heat utilization,reduce pests and diseases,and increase output per unit area,thereby maximizing economic benefits.

茄子与平菇、甘蓝、甘薯间作对其长势、产量及根际环境的影响

为避免因茄子连年种植导致的土传病害增加而对茄子生产造成影响,形成健康、生态的解决办法,以茄子不间作为对照,研究分析了茄子与平菇、甘蓝、甘薯3种作物分别间作后对其长势、产量及根际环境的影响。结果表明:与对照相比,茄子与3种作物间作对茄子株高日均生长量、茎粗、单株坐果数、单果质量、667 m^(2)平均产量以及根际土壤干质量、含水量、EC值、碳氮比、有机碳含量、无机碳含量、有机质含量、速效磷含量均未造成显著影响;茄子与甘蓝间作较与平菇、甘薯间作可显著降低土壤干质量和速效钾含量,且较对照分别降低了8.58%和11.11%,这有利于土壤孔隙度的增加,同时较对照极显著提高了茄子根际细菌总量,显著提高了根际真菌总量及根际细菌与真菌总量比值,分别较对照提高114.44%、42.18%和49.56%,这有助于茄子连作障碍的消减及土传病害的防治;茄子与平菇间作极显著降低了根际土壤的pH值,较对照降低5.36%,极显著降低了土壤全碳含量和全氮含量,分别降低16.99%和17.10%,但显著提高了土壤速效氮含量,增幅达36.10%,极显著提高了根际细菌总量和真菌总量,分别提高71.84%和156.98%;茄子与甘薯间作,极显著降低了根际土壤的pH值,降幅达7.39%,但显著提高了土壤速效钾含量和根际真菌总量,极显著增加了根际细菌总量,增幅分别达27.76%、56.98%和99.67%。综合上述分析认为,茄子与甘蓝间作有利于改善土壤团粒结构,丰富、稳定土壤生态系统,有助于作物植株健康生长,但间作时需要及时补充钾肥;而茄子与平菇、甘薯间作会降低土壤pH值,提高土壤肥力,可用于盐碱土或“生”土的改良。

间作作物种间相互作用对土壤细菌群落的影响

为揭示作物种植模式对土壤细菌群落组成及功能的影响机制,利用田间定位试验,基于宏基因测序方法,开展连续单作马铃薯(P)、单作玉米(M)、间作马铃薯(IP)、间作玉米(IM)根际土壤细菌群落组成和功能差异研究,分析土壤细菌群落结构、功能与土壤理化性状、间作作物产量间的相互关系。结果表明:与对应单作处理相比,玉米、马铃薯间作整体上具有产量优势。土壤变形菌门、放线菌门和浮霉菌门为不同处理下细菌群落的优势菌群;属分类水平上链霉菌属、慢生根瘤菌属、鞘脂单胞菌属、伍氏束缚菌属、伯克氏菌属、藤黄色杆菌属为优势菌属。马铃薯单作及间作处理下根际土壤鞘脂单胞菌属相对丰度均极显著高于玉米处理(P<0.01)。通过KEGG数据库不同功能层的功能预测表明,不同处理得到455个三级功能类别和9 636个四级类别,其中参与C、N循环的通路数最多。相关性分析表明,土壤含水量(SOW)、土壤呼吸强度(RI)和速效磷(AP)对根际土壤细菌群落组成及功能代谢具有积极影响;SOW、RI和AP与功能类别中K01990和K06147均有显著或极显著相关性。连续6 a马铃薯、玉米间作及单作下作物根际土壤细菌群落组成和功能的变化是由作物种间关系变化驱动土壤养分、土壤微生物功能代谢差异影响的。

豫西旱地烟薯间作模式下不同株距对烤烟生长及产量质量的影响

为探索适宜豫西旱地烤烟高质量发展的烟薯产业综合体模式,以烤烟‘LY1306’和鲜食甘薯‘普薯32’为材料,采用田间试验研究“烟垄栽薯”2∶2间作模式下烤烟不同株距(65、60 cm和55 cm)配置对烟株生长及产量质量的影响。结果表明:在烟株移栽后90 d,与烤烟单作相比,烤烟株距为65 cm时,烟薯间作烟叶的最大叶长和最大叶宽分别提高5.09%~5.12%和5.17%~8.17%,叶绿素相对含量(SPAD值)提高4.90%~6.81%,净光合速率(P_(n))、气孔导度(G_(s))和蒸腾速率(T_(r))分别提高16.39%~21.50%、23.82%~27.72%和36.21%~45.31%,土传根茎病害发病率降低74.38%~78.42%;烤烟株距为60 cm时,烟薯间作烟叶的最大叶长和最大叶宽分别提高3.71%~4.79%和4.69%~7.61%,SPAD值提高3.80%~5.55%,P_(n)、G_(s)和T_(r)分别提高14.03%~19.77%、15.68%~22.49%和29.83%~35.78%,土传根茎病害发病率降低75.30%~78.11%;两种株距下烤后烟叶内在化学成分配比较烤烟单作更为合理。随着烤烟株距的减小,间作处理的土地当量比(LER)、总产值及烤烟感官评吸总分表现为先增加后减小;当烤烟株距为60 cm时,烟薯间作的总产值在2021年和2022年分别达82 855.40 CNY·hm^(-2)和81 654.55 CNY·hm^(-2),较烤烟单作提高15.85%和22.43%。综上,豫西旱地采用“烟垄栽薯”2∶2间作模式的LER>1,具有间作优势,且烤烟株距调整为60 cm时(烤烟单作株距65 cm),烟株生长较好,产量质量指标最优,综合效益最大。

胶园间作不同马铃薯品种对土壤性质及微生物多样性的影响

本研究以橡胶单作为对照,采用生物化学分析方法和高通量测序技术,分析间作不同马铃薯品种后胶园土壤化学性质、酶活性以及微生物多样性的变化规律。研究结果表明:胶园间作不同马铃薯相比橡胶单作能显著提高土壤有机质、全氮、全磷、全钾、碱解氮和有效磷含量及土壤β-葡萄糖苷酶、N-乙酰-β-D-葡萄糖苷酶、酸性磷酸酶和芳基硫酸酯酶活性,不同品种间存在显著差异,对土壤养分影响排序为:剑川红>紫薯>大牛角,对土壤酶活性影响排序为:大牛角>剑川红>紫薯。胶园间作马铃薯显著提高土壤微生物的丰富度指数和多样性指数,品种间不存在显著差异。但不同品种对土壤特定菌群丰度影响存在显著差异,总体趋势是显著降低特有细菌如绿弯菌门(Chloroflexi)、脱硫菌门(Desulfobacterota)等的丰度,显著增加特有真菌如被孢菌门(Mortierellomycota)、壶菌门(Chytridiomycota)、梳霉门(Kickxellomycota)等的丰度。LEfSe分析发现间作马铃薯富集了一些参与物质循环或具有拮抗植物病原菌的有益微生物,大牛角、紫薯和剑川红分别富集了16、26和31种标志微生物。冗余分析和相关性分析发现,土壤养分和酶活性与胶园土壤特定细菌、真菌门丰度有显著相关性,养分和酶活性增加,降低细菌门丰度,增加真菌门丰度。综上所述,间作马铃薯显著提高了胶园土壤养分、酶活性以及土壤微生物群落多样性,降低特定细菌门和增加特定真菌门的丰度;不同马铃薯品种对土壤养分和酶活性的影响存在显著差异,可能与其富集不同有益微生物相关。本研究为胶园林下间作提供了新的思路和数据支撑。

不同作物与甘薯间作对甘薯田昆虫群落的影响

【目的】探究不同间作模式下甘薯田昆虫群落的组成变化,为甘薯虫害生态控制提供思路。【方法】通过目测法和马氏网法,调查记录不同间作处理下甘薯试验田昆虫的种类和数量,利用物种丰富度指数、均匀度指数、多样性指数和群落生态优势度等指标进行分析。【结果】调查采集到昆虫2547只,分属于8目74科275种,主要包括鳞翅目、双翅目和膜翅目等。不同间作处理的甘薯田昆虫群落组成在科和种水平上均存在差别,甘薯-罗勒间作的科数最多,为51科,而甘薯单作的种数最多,为73种。不同间作处理的甘薯害虫与益虫的数量均存在差别,甘薯单作的害虫数量最多,为375只;甘薯-大豆间作、甘薯-玉米间作和甘薯-罗勒间作的害虫数量分别比甘薯单作的害虫数量减少了12.00%、25.07%和26.67%;甘薯-大豆间作的益虫数量最多,为168只。其中,白斑烦夜蛾为田间害虫的优势种,粉蝶盘绒茧蜂为田间益虫的丰盛种。通过对丰富度指数、多样性指数和群落均匀度指数比较发现,各处理的害虫群落的多样性和均匀度高于益虫群落;其中甘薯-大豆间作的益虫群落多样性指数为0.3120、群落均匀度指数为0.0900,均高于其他处理。【结论】甘薯间作在一定程度上可降低害虫发生的数量、多样性以及均匀度,具有良好的生态效益。

辽西北风沙地苹果与红薯间作系统土壤养分季节动态特征及养分效应分析

通过对苹果与红薯间作系统不同季节土壤养分动态变化情况及与单独种植间的养分效应进行的对比研究,结果表明:间作系统整体养分含量呈下降趋势,但7月对养分的消耗最多,养分中的氮、钾需要及时补充,磷则消耗较少;间作系统的全氮和速效钾比红薯单作消耗少,但总体养分消耗比苹果单作多。

向日葵和马铃薯间作模式的生产力及水分利用

本研究通过对不同间作模式中作物水分吸收和利用的分析比较,探讨间作提高产量的机理,提出适合当地生态环境的最优间作模式,并提供一定理论依据。于2009年和2010年在内蒙古武川进行了大田试验,研究马铃薯/向日葵不同间作模式水分吸收和利用,结果表明,马铃薯/向日葵2种间作模式:2行马铃薯:2行向日葵(2P:2S)和4行马铃薯:4行向日葵(4P:4S)的土地当量比LER为1.2～1.3,都具有较强的间作产量优势。其中,4P:4S间作体系2年平均的LER为1.26,间作优势最大。4P:4S间作马铃薯的农田蒸散量ET与单作马铃薯的ET相比差异不显著。单作向日葵和间作向日葵的农田蒸散量ET无显著差异。虽然,2P:2S间作模式和4P:4S间作模式的马铃薯水分利用效率WUE比单作分别降低了81%和66%,但2种间作模式下向日葵的水分利用效率与单作相当。因此,在马铃薯和向日葵间作模式中,整体的水分利用效率提高了,水分当量比WER在1.2～1.3,其中4P:4S间作系统的水分当量比2a均为1.3,说明该体系具有显著的水分利用优势。综合分析认为,马铃薯/向日葵间作特别是4P:4S间作模式有利于提高土地生产力和农田水分的利用效率,在可持续雨养农业发展中具有很好的应用价值。

马铃薯/玉米套作对马铃薯品种光合特性及产量的影响

以马铃薯品种中薯5号(早熟,株型直立)和米拉(中晚熟,株型扩散)单作为对照,在大田条件下,调查马铃薯/玉米套作模式中2个品种光合指标的变化、块茎形成期至块茎增长期不同叶位气体交换参数的变化,分析光合指标对产量的影响。结果表明,整个生育期马铃薯叶绿素含量(Chla+Chlb)套作高于单作,叶面积指数(LAI)、比叶重(SLW)和叶绿素a/b值(Chla/b)套作低于单作。从块茎形成期至块茎增长期,群体光合有效辐射(PAR)、水分利用效率(WUE)、气孔限制值(Ls)呈下降趋势,净光合速率(Pn)、气孔导度(Gs)、胞间二氧化碳浓度(Ci)、蒸腾速率(Tr)呈上升趋势。PAR、Pn、Gs、Tr均随叶位的降低显著下降,套作下降幅度低于单作。套作中、下层叶片Pn的下降受气孔因素和非气孔因素限制。套作降低了马铃薯上层叶Pn,提高了中、下层叶Pn。套作中薯5号的Chla+Chlb生育前期高于米拉,生育后期低于米拉,SLW则相反;LAI和Chla/b整个生育期高于米拉。套作中薯5号上层叶PAR高于米拉,中、下层叶PAR低于米拉;套作中薯5号上层叶Pn与米拉相近,中、下层叶Pn高于米拉;各层叶WUE、Ls高于米拉,Gs、Ci、Tr低于米拉。总之,套作改变了马铃薯的光合特性,并显著降低了马铃薯块茎产量;套作恶化了中薯5号/玉米复合群体的光环境,改善了米拉/玉米复合群体的光环境,米拉/玉米套作体系土地当量比(1.40)大于中薯5号/玉米体系(1.24),显示了较强的套作优势,宜在生产中优先推广。

薯/豆套作模式下不同熟期大豆品种的生长补偿效应

【目的】探讨马铃薯/大豆套作复合群体品种搭配原则,为马铃薯/大豆套作高产高效提供理论和技术依据。【方法】以当前西北一熟制灌区生产中广泛种植且间套优势明显的早熟马铃薯/大豆间套作方式为研究对象,通过两年田间试验,以大豆品种中黄30(早熟)、冀豆17(中熟)和齐黄34(晚熟)单作为对照,分析套作马铃薯收获前后大豆叶面积指数、干物质积累、光合速率的变化及对产量构成因素的影响,评价不同熟期大豆品种的生长补偿效应。【结果】(1)相对于单作,套作条件下各大豆品种的开花期延迟7 d左右,但不影响全生育期,套作大豆营养生长期延长而生殖生长期相对缩短。马铃薯与大豆各品种间的共生期差异不显著,但其生殖生长共生期差异显著(齐黄34为12 d,冀豆17为35.5 d,中黄30为41.5 d)。(2)在马铃薯/大豆共生期间,套作大豆LAI上升慢于单作,晚熟大豆LAI慢于早熟和中熟大豆品种,在马铃薯收获后,中、晚熟大豆品种可保持较大叶面积指数并持续较长的时间,尤其是晚熟品种。(3)单作大豆在出苗后60 d内干物质积累较快,而同期套作大豆平均干物质积累为单作大豆的44.27%。不同品种间单作大豆净光合速率高于套作,其中,晚熟品种显著高于中、早熟品种(P<0.05);出苗后100 d(套作马铃薯已经收获)单作大豆干物质积累相对变缓,套作大豆生长加快,尤其是晚熟品种增幅显著,此时套作大豆Pn相对于单作上升幅度大,中、晚熟品种Pn接近于单作大豆。(4)较单作模式,套作模式下不同大豆品种的有效荚数、单株粒数及每荚粒数均有所降低,其中早熟品种下降显著(P<0.05),分别下降了24.15%、22.14%、18.92%,而中、晚熟品种下降不显著,尤其是晚熟品种,套作模式较单作模式仅仅下降了6.34%、8.3%、1.71%。套作模式下,中、晚熟大豆品种的产量较早熟品种分别提高了79.85%和145.08%,LER分别达到了1.77和1.83。【结论】中、晚熟大豆品种与马铃薯组合套作优势更强,其生育期较长,营养生长期相对延长导致生殖生长共生期缩短,使大豆叶面积指数、光合速率均保持在较高水平,从而为马铃薯收获后进行光合补偿生长提供物质和能量基础,保证了套作大豆较高产量。

马铃薯/燕麦间作对马铃薯光合特性与产量的影响

在宁夏南部山区,通过田间小区试验,以单作马铃薯为对照,研究了4种马铃薯燕麦间作行数比[2∶2(P2O2)、2∶4(P2O4)、4∶2(P4O2)、4∶4(P4O4)]对马铃薯光合特性与产量的影响。结果表明,开花期,间作马铃薯的叶面积指数(LAI)、比叶重(SLW)显著下降,随着第1茬燕麦的收获,间作马铃薯能获得更多的光照和更广阔的生长空间,良好的通风透光条件使SLW有一定程度的回升;成熟期间作LAI高于单作。整个生育期P4O4处理的LAI和叶绿素总含量(Chla+Chlb)显著高于其他间作处理。在开花期,与单作相比,间作马铃薯叶片的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)显著降低,胞间CO2浓度(Ci)显著提高;成熟期,光合指标的变化趋势与开花期相反。与单作相比,间作马铃薯由于增加了单株块茎重、单株商品薯重,减少了小薯个数,而使产量显著增加,P4O4产量最高。马铃薯/燕麦间作具有一定的间作优势,各间作处理经济产量土地当量比(LER)均大于1,其中P4O2的土地当量比最大,为1.22;其次为P4O4处理。在马铃薯/燕麦间作生产中适当增加马铃薯行数或减少燕麦行数有利于增加间作优势,在生产中宜采用马铃薯与燕麦间作行数比为4∶2、4∶4的间作模式。

冀西北坝上半干旱区南瓜油葵间作的水分效应

针对冀西北高原水源匮乏、利用低效问题,于2009—2010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通过南瓜//油葵不同间作群体结构试验,探讨了该区南瓜水分高效的种植方式。试验设南瓜单作(Sp),南瓜行间作1行油葵(IC1),南瓜行间作2行油葵(IC2)和油葵单作(So)4个处理。结果表明,南瓜行间种植两行油葵(IC2)在南瓜生长中后期出现了油葵与南瓜争夺水分的现象,而南瓜行间种植一行油葵(IC1)无此现象。各处理间水量平衡各分量有较大的差异,在整个生育时期降雨量为201.6mm的情况下,渗漏量占的比重非常小,并且土壤蓄水量变化均为负值,绝大部分水分都是以气态水蒸散掉,但不同间作方式蒸散失水量不同,其中IC1较So、Sp和IC2分别少散失土壤水分36.33%、19.00%和34.87%。得益于油葵的偏利效应使南瓜经济产量下降30.00%—71.42%,而间种油葵单株产量相对单作田提高190.71%—241.26%,虽其土地当量比LER和水分当量比WER分别达1.08—1.22和1.07—1.26,但IC1复合群体的经济效益只能与南瓜单作田持平,其他处理明显低于单作南瓜。在冀西北高原雨养背景下,稀植高效的南瓜单作生产能够实现对区域水资源的高效利用。

间作对玉米马铃薯根系生长与分布的影响

【目的】旨在研究玉米马铃薯间作条件下作物根系生长与分布特征。【方法】以玉米马铃薯间作、玉米单作、马铃薯单作为研究对象,采用空间坐标取样法对根系取样。【结果】(1)玉米马铃薯的根系质量密度分布随土层深度增加而降低,在>10~20 cm的土层中降低趋势最快,最大值都出现在0~10 cm的土层中。(2)2013年和2014年马铃薯初花期玉米根系质量密度在不同土层都是边二行大于单作和边一行,边一行最小,说明马铃薯初花期间作抑制玉米边一行根系生长,成熟期玉米边一行的根系质量密度反而最大,说明成熟期促进了边一行的根系生长,导致最终了间作玉米的根系质量密度大于单作玉米。(3)无论是马铃薯初花期还是成熟期,马铃薯根系质量密度在0~10 cm土层中边一行明显大于边二行,而到>20~30 cm时边一行小于边二行,说明间作有利于马铃薯边一行根系生长的同时促进马铃薯边二行根系向更深土层扩展,使得间作马铃薯的根系质量密度也大于单作马铃薯。(4)间作系统中玉米根系无论在马铃薯初花期还是成熟期都有向马铃薯生长的趋势,而马铃薯根系在成熟期有向玉米生长的趋势。【结论】因此,玉米间作马铃薯根系分布较为合理,使得间作的根系质量密度大于单作,这为玉米马铃薯间作产量优势的形成具有重要的意义。