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1.
Sudden death syndrome, caused by Fusarium virguliforme, and the soybean cyst nematode, Heterodera glycines, combined cause the highest yield losses in soybean. The objective of this study was to determine the effectiveness of corn rotated annually with soybean on reducing severity of sudden death syndrome (SDS) and if such crop rotation is beneficial to soybean root health and thus improves disease management strategies. Experiments were conducted from 2003 to 2006 through two cycles of a corn–soybean rotation on two commercial fields in Indiana. With one exception, the rotation of soybean with corn did not provide yield benefits compared to monoculture of soybean. Severity of foliar and root symptoms of SDS in rotation plots were never less than in soybean monoculture plots. At one location, soybean monoculture resulted in suppression of SDS compared to the corn–soybean rotation, while H. glycines reproduced freely. At the other location, monoculture of soybean resulted in suppressiveness against H. glycines, while SDS was limited in all treatments. The data suggest that soil suppressiveness can independently impact the pathogens that are important in SDS development. Because H. glycines can increase SDS symptoms, its suppression may also reduce severity of SDS. Current production systems consisting of yearly rotation of soybean with corn are highly vulnerable to the development of severe soil-borne disease complexes. The simple year-to-year rotation of corn and soybean is not considered sustainable. While monoculture of soybean resulted in some disease suppression in these trials, reliance on monoculture may be detrimental due to other environmental considerations beyond the scope of these trials. Including other crops may be beneficial in improving the sustainability of soybean and corn production systems. 相似文献
2.
草害是造成大豆减产的主要因素之一。本试验通过系统观察大豆田杂草消长规律,对大豆播后不同时期人工除草的保产效果进行了对比试验研究。结果表明:本地大豆田杂草有两个发草高峰,出现时间分别在大豆播后18～30天和37～48天。大豆田杂草防除临界期为大豆播后18～30天,在此期内除草一次,保产效果最佳。 相似文献
3.
不同除草剂对间作玉米大豆的药害及除草效果 总被引：2，自引：0，他引：2
采用盆栽方法模拟玉米大豆间作模式栽培,选用10种土壤处理除草剂和13种茎叶处理除草剂,研究不同除草剂对玉米、大豆生长发育的影响及杂草的防效。结果表明:通过试验筛选出药害轻或药害后能恢复的5种土壤处理剂和5种茎叶处理剂,5种土壤处理剂分别为二甲戊灵、精异丙甲草胺、扑·乙·滴丁酯、乙·嗪·滴丁酯、嗪酮·乙草胺,5种茎叶处理剂分别为灭草松、噻吩磺隆、双氟·唑嘧胺、氟醚·灭草松、咪唑乙烟酸。二甲戊灵和嗪酮·乙草胺的土壤处理中玉米、大豆的株高、茎粗和干物重与清水对照差异不显著,对玉米、大豆安全,株防效分别为60.58%和60.58%,鲜重防效分别为67.12%和55.35%。精异丙甲草胺影响间作玉米的株高和茎粗,但不影响玉米干物质的积累,株防效和鲜重防效分别为71.96%和78.83%,高于其它除草剂。茎叶处理中灭草松安对玉米、大豆的株高、茎粗和干物重与清水对照差异不显著,株防效为52.7%,低于其它除草剂。噻吩磺隆处理后,玉米、大豆的株高受到抑制,茎增粗,但药害能恢复,且除草效果高于其它处理,株防效和鲜重防效分别为73.88%和96.1%。土壤处理剂二甲戊灵和茎叶处理剂灭草松对玉米、大豆更安全,土壤处理剂精异丙甲草胺和茎叶处理剂噻吩磺隆除草效果更好。 相似文献
4.
Glyphosate-resistant (GR) volunteer corn is a troublesome weed in soybean fields in a corn-soybean rotation as well as in corn fields in a continuous corn production system. The objectives of this study were to evaluate the impact of (1) different densities of GR volunteer corn on soybean yields, present as individual plants or clumps, controlled at fourth trifoliate (V4), sixth trifoliate (V6), or full flowering (R2) soybean growth stages, and (2) late-season volunteer corn emergence on soybean yields, after being controlled at different soybean growth stages. Field experiments were conducted in 2013 and 2014 under irrigated conditions in Clay County, Nebraska, and under rain-fed conditions in Lancaster County, Nebraska, USA. To maintain the desired number of isolated volunteer corn plants (1250, 2500, 5000, and 10,000 plants ha−1) and clumps (63, 125, 250, and 500 clumps ha−1), individual seeds and/or corn ears were hand-planted in each plot based on their respective target densities. Volunteer corn was controlled with applications of clethodim at V4, V6, or R2 soybean growth stages. Late-season volunteer corn emergence had no effect on soybean yield with volunteer corn densities and control timings at both locations in 2013 and 2014. During the first year of study at Clay County, volunteer corn densities and control timings had no effect on soybean yield. When volunteer corn was left uncontrolled or controlled at the R2 soybean growth stage, yield was the lowest at highest isolated volunteer corn plants (10,000 plants ha−1) plus clump density (500 clumps ha−1) during the second year of study in Clay County (≤5068 kg ha−1) and during both years of study in Lancaster County (≤1968 kg ha−1). 相似文献
5.
In recent years flaxleaf fleabane has become a widespread and difficult-to-control weed in no-tilled fallowed fields, where weeds are controlled by applications of glyphosate, in annual cropping systems of north-east Australia. Fifty-two populations, collected in a national survey from agricultural and non-agricultural areas, were tested in two glyphosate dose-response pot experiments. In two subsequent pot experiments, a sub-set of these populations was tested with a field rate of glyphosate when weeds of two ages were grown at different soil moistures. In the first and second experiments, most populations collected from chemical fallowed or cropped fields in north-east Australia had GR50 (estimated dose for 50% biomass reduction) values three to six times greater than the susceptible populations, indicating low levels of glyphosate resistance. Several populations from roadsides adjacent to chemical fallowed or cropped fields also had higher GR50 values, indicating movement of seeds from resistant plants. In the third experiment, weed biomass of all populations from chemical fallowed or cropped fields was 70-98% of unsprayed compared to 2-3% for the susceptible populations, irrespective of weed age or soil moisture. In the fourth experiment which treated older weeds, the response of several resistant populations to glyphosate was unaffected by differences in weed age and soil moisture, whereas the biomass of the other resistant populations was greater following spraying of older and/or moisture stressed plants compared with smaller non-stressed plants. Thus, exclusive reliance on glyphosate for fallow weed control in this region has resulted in the evolution of resistance in flaxleaf fleabane populations in a cropping system with annual non-transgenic crops. Prolific production of windborne seeds, combined with poor control associated with spraying large moisture-stressed weeds, is likely to have contributed also to flaxleaf fleabane becoming such a problem weed. 相似文献
6.
不同耕作模式对玉米田杂草发生规律的影响 总被引：7，自引：3，他引：4
在免耕、旋耕和翻耕玉米田试验区调查杂草种类和出苗数量,并在玉米生长中后期调查杂草种类、株数和鲜重。结果表明,不同耕作模式玉米田杂草发生规律有明显差异。免耕、旋耕和翻耕玉米田禾本科杂草高峰期都在播种后5周发生;阔叶杂草发生高峰期不同,免耕田为播种后1周,旋耕和翻耕田均在播种后2周。杂草种类不同,玉米生长中后期,免耕田有8种杂草,旋耕田有10种,翻耕田有12种;杂草发生总量不同,免耕田杂草总量最多,旋耕田居中,翻耕田最少;杂草单株鲜重不同,免耕田杂草单株鲜重最低,旋耕田居中,翻耕田最高。 相似文献
7.
《Journal of Crop Improvement》2013,27(1):207-224
Abstract Selecting effective weed management options requires biological, ecological, and economic information. This study compared model-based to standard-herbicide weed control in a corn (Zea mays L.)/soybean [Glycine max (L.) Merr.] rotation that had a long-term history of different tillage and weed management practices. The model integrates weed population dynamics, herbicide efficacies, and economic information to evaluate preplant incorporated (PPI) or preemergence (PRE) weed control options based on weed seed bank size and postem-ergence (POST) strategies based on weed seedling densities. There were fewer weeds in standard-herbicide compared with model-based treatments. No-tillage had the greatest numbers of weeds 3 out of 4 years. Soybean yield was reduced the first year of the study in several treatments receiving model-based weed control and the third year in all model-based treatments. Corn yields were greatest in reduced tillage. Resuits of using model recommendations to control weeds were mixed, with PRE recommendations being insensitive to a common cocklebur (Xan-thium strumarium L.) infestation. Our conclusions agree with those of others that the nature of the weed pressure may be a prevailing influence on the outcome of using weed control recommendations of bioeconomic models. 相似文献
8.
2016～2017年在东北春玉米种植区和黄淮海夏玉米种植区设立田间试验基地,研究除草剂异噁唑草酮·噻酮磺隆悬浮剂在不同区域玉米田播后苗前处理的杀草谱及除草效果、对玉米安全性及对下茬作物生长的影响。结果表明,26.7%异噁唑草酮·噻酮磺隆悬浮剂141.75～283.5 g ai/hm2在玉米播后苗前使用,对东北春玉米种植区主要杂草稗草、狗尾草、藜、反枝苋、苘麻、刺儿菜和黄淮海玉米种植区主要杂草马唐、牛筋草、反枝苋、马齿苋、铁苋菜等禾本科杂草和阔叶杂草均有理想效果,药后40～45 d,异噁唑草酮·噻酮磺隆上述处理对杂草鲜重防效仍在95%左右,可实现一次施药控制玉米全生长期的杂草,在玉米田具有较好的除草增产作用;对后茬播种的小麦、大豆、花生、油菜、菠菜生长无影响。 相似文献
9.
研究30%烟嘧磺隆·莠去津·硝磺草酮可分散油悬浮剂在甜玉米田的应用效果,在甜玉米不同叶龄期开展田间试验,评价其对杂草的防除效果及对甜玉米的安全性。结果表明,30%烟嘧磺隆·莠去津·硝磺草酮可分散油悬浮剂在甜玉米3～4叶期或6～7叶期施药,900～1 575 g a.i./hm2剂量范围内对甜玉米品种粤甜28安全,对玉米田常见杂草凹头苋、光头稗、马唐和香附子的防效及增产效果均显著高于对照药剂38%莠去津悬浮剂2 160 g a.i./hm2播后苗前处理。推荐30%烟嘧磺隆·莠去津·硝磺草酮可分散油悬浮剂在900～1 350 g a.i./hm2范围内,甜玉米3～5叶期茎叶喷雾使用。 相似文献
10.
11.
对4个大豆品种与牛筋草的竞争关系进行了研究，结果表明，不同大豆品种对杂草干扰的反应有显著差异，大豆种子产量损失率在25％～38％；牛筋草生物量和单株种子重量受大豆影响而显著降低，但大豆品种间没有显著差异。 相似文献
12.
Much of our understanding of weed communities and their interactions with crops comes from studies conducted at, or below, the spatial scale of individual fields. This scale allows for tight control of experimental variables, but systematically ignores the potential for regional-scale environmental variation to affect agronomic operations and thereby influence weed management outcomes. We quantified linkages among agronomic, environmental and weed management characteristics of 174 commercial sweet corn fields throughout the north central United States and evaluated crop and weed responses to these variables using classification and regression tree (CART) analysis. Multi-model selection indicated that characteristics of weed management systems, especially total cost and herbicide rate, were important predictors of weed diversity, interference and fecundity. Adding agronomic variables, such as planting date, or environmental variables, such as latitude, explained additional variation in weed floristic measures. We tested yield predictions of the most parsimonious CART model against a verification data set comprised of over 1500 published observations from 25 experiments conducted in the major North American regions where sweet corn is grown for processing. Yield values fell within the 95% confidence interval of observed data for most branches of the tree, suggesting the experimental and analytical approaches were reasonably robust. Several characteristics favoring sweet corn productivity and weed management sustainability were identified. This work resulted in easily interpretable models, both by scientists and producers, which place crop and weed responses within the context of regional-scale variation in agricultural management and the environment. 相似文献
13.
Mila P. Hojilla-Evangelista Roque L. Evangelista Y. Victor Wu 《Industrial Crops and Products》2009,29(2-3):275-280
Milkweed (Asclepias spp.) is a crop grown mainly for the production of floss used as hypoallergenic fillers in comforters and pillows. The seeds end up as by-products. Milkweed seed contains 21% oil and 30% crude protein (dry basis). The oil is similar in quality to soybean oil, but there is no information on the properties of milkweed protein. This study determined the MW of major fractions, soluble classes, amino acid composition, and functional properties of milkweed seed protein. Ground milkweed seeds were analyzed for proximate composition and amino acid profile, as well as, subjected to SDS-PAGE and protein functionality tests. Reduced proteins showed eight distinct bands with MW ranging from 6.5 to 59.3 kDa. The dominant protein classes were water-soluble (22%) and salt-soluble (15%). Solubility of milkweed seed protein was lowest (12%) at pH 4, 40% at pH 7, and reached a maximum (60%) at pH 10. The protein produced substantial foam volumes, but foam stability was poor. Its emulsifying capacity was excellent, especially at pH 10, and emulsions formed were stable. Water-holding capacity and surface hydrophobicity index values were higher at pH 7 than at pH 10. These results showed that milkweed seed protein has functional properties that may find use as a thickener, protein extender in adhesives, or emulsifier in paints. 相似文献
14.
概述了影响北部大豆田化学除草剂应用效果的自然气候,杂草演变,施用技术,人为因素等,就影响因素进一步提出了相应解决对策。 相似文献
15.
The chrysomelid beetle Colaspis crinicornis Schaeffer (Coleoptera: Chrysomelidae) occurs primarily in the Great Plains region of the United States. Little is known about the biology and ecology of this species, but over the last decade, it has become increasingly common in the corn, Zea mays L., and soybean, Glycine max (L.) Merrill, agroecosystem of southeastern Nebraska. As part of a larger comprehensive project to understand the natural history and pest potential of this species, laboratory experiments were conducted to study the developmental biology, morphological characters of immature stages, and the effect of adult diet on consumption, longevity, and fecundity. Females readily deposited egg clusters in the soil, and percentage egg hatch was high under laboratory conditions. Larvae and pupae were confirmed to be soil-dwelling stages. C. crinicornis has relatively short egg, pupal, and adult stages with the majority of its life cycle spent in the larval stage. Results of choice and no-choice adult feeding experiments indicate that diets of corn or soybean leaves did not significantly affect consumption, longevity, or fecundity of adult C. crinicornis, suggesting that corn and soybean leaves are similarly suitable food sources for adults. The ability to effectively utilize tissues from very different plant families as adult food sources suggests that C. crinicornis is polyphagous in the field. 相似文献
16.
The Mexican rice borer, Eoreuma loftini (Dyar), is the key pest of sugarcane, Saccharum hybrids, in south Texas, having largely displaced the sugarcane borer, Diatraea saccharalis (F.), and it is moving into rice- and sugarcane-growing areas of east Texas and Louisiana. While a number of alternative weed and crop hosts have been reported, the extent to which they might support Mexican rice borer populations is unknown. This study involved choice assays that compared oviposition preference for and larval infestations of five mature graminaceous weed species. Levels of infestation between sugarcane and corn, Zea mays L., crop hosts and between corn and sorghum, Sorghum bicolor (L.) Moench, were also assessed. We determined that the average number of larval entry holes in sudangrass stems was ≥2.5-fold more than for any of the other four weed host plants, that corn had ≥5.9-fold more larval entry holes than sorghum and ≥8.2-fold more than sugarcane. Greater oviposition and infestation of one non-crop host over another was not related to numbers of stems per plant, but was associated with the greater stem diameter and abundance of dry leaf tissue found in Sudangrass, Sorghum bicolor (L.) Moench ssp. drummondi (Nees ex Steud.) de Wet & Harlan, johnsongrass, S. halepense (L.) and barnyardgrass, Echinochloa crus-galli (L.) P. Beauv.; relative to the other weed species in this study. In terms of the crop plants, stalk diameter and quantity of dry leaf tissue were not associated with numbers of eggs or larval entry holes in the choice assays between corn and sorghum, and between sugarcane and corn. While corn has been known as a host of the Mexican rice borer for at least 84 yr, its role in area-wide population dynamics and control efforts has likely been greatly underestimated. 相似文献
17.
Performance consistency of reduced atrazine use in sweet corn 总被引：1，自引：0，他引：1
Martin M. Williams II Rick A. BoydstonR. Ed Peachey Darren Robinson 《Field Crops Research》2011,121(1):96-104
Atrazine is the most widely used herbicide in North American corn production; however, additional restrictions on its use in the near future are conceivable. Currently, a majority of commercial sweet corn fields suffer losses due to weeds, despite widespread use of atrazine. Field experiments were conducted in the primary North American production areas of sweet corn grown for processing to determine the implications of further reductions in atrazine use on weed control and crop yield. A range of atrazine doses (0-1120 g ha−1) applied postemergence with tembotrione (31 g ha−1) were tested in two hybrids differing in canopy architecture and competitive ability with weeds. Atrazine applied postemergence reduced risk (i.e. more variable outcomes) of poor herbicide performance. Atrazine doses up to 1120 g ha−1 with tembotrione improved grass control and broadleaf weed control in five of eight and seven of eight environments, respectively. Of the three environments which had particularly low broadleaf weed control (<50%) with tembotrione alone, sweet corn yield was improved with atrazine. Hybrid ‘Code128’ produced a taller, denser canopy which was more efficient at capturing light and competing with weeds than ‘Quickie’. As a result, greater crop competitiveness decreased risk of incomplete weed control as atrazine dose was reduced. Atrazine's contribution to weed control and yield protection was greatest when other aspects of weed management resulted in poor weed control. Should atrazine use be further restricted or banned altogether, this research demonstrates the importance of improving other aspects of weed management systems such as herbicidal and non-chemical tactics. 相似文献
18.
东北部分春玉米地乙莠合剂防效下降的原因和对策 总被引：1，自引：0，他引：1
在我国的东北春玉米区,长时间使用乙草胺和莠去津,导致部分地区防效下降。在吉林省农安县通过定点试验、大面积试验和大范围调查发现,乙莠合剂防效下降的主要原因是因为杂草群落结构的变化引起的,同时降水的减少和药剂使用方法不当也起了一定的作用,未发现产生明显抗性的迹象。在未来,乙莠合剂仍是该地区玉米地除草剂的主要药剂,对于杂草群落尚未发生变化的地块仍然有很好的防效,而在杂草群落发生变化的地区,应适当更换除草剂或适当增加轮作;针对当地特点,适当推迟乙莠合剂的喷施时间,采用机械喷雾、加大用水量等措施来提高乙莠合剂的防效。 相似文献
19.
Knowledge of the crop-weed competition period is vital for designing effective weed management strategies in crop production systems. Field studies were conducted at the Agricultural Research Institute, Kahramanmaras, Turkey in 2013 and 2014 to determine the critical period for weed control (CPWC) in three corn (Zea mays L.) types (field corn, popcorn, and sweet corn). A four parameter log-logistic model described the relationship between relative crop yield to both increasing duration of weed interference and length of weed-free periods. The relative yield of corn was influenced by duration of weed-infested or weed-free period, regardless of corn types. Increasing periods of weed interference significantly reduced corn yields in both years. In field corn, the CPWC ranged from 175 to 788 growing degree days (GDD) in 2013 which corresponded to V2–V12 growth stages, and 165–655 GDD (V1–V10 growth stages) in 2014 based on the 5% acceptable yield loss (AYL) level. In popcorn, the CPWC ranged from 92 to 615 GDD (VE–V10 growth stages) in 2013 and 110–678 GDD (V1–V10 growth stages) in 2014. In sweet corn, the CPWC ranged from 203 to 611 GDD in 2013 (V2–V10 growth stages) and 182–632 GDD (V2–V10 growth stages) in 2014. The practical implication of this study is that weed management should be initiated around V1 stage and maintained weed-free up to V12 stage in all corn types to prevent yield losses greater than 5%. These findings could help corn producers improve the cost effectiveness and efficacy of their weed management programs. 相似文献
20.
利用吉林省梨树县黑土区氮肥长期定位试验田(施氮水平为0、60、120、180、240、300 kg/hm~2),2019～2020两年调查玉米田杂草种类、密度和生物量及其与玉米生物量和产量的关系。结果表明,试验条件下玉米田杂草主要是禾本科杂草,尤其是水稗草Echinochloa oryzoides。与不施肥相比,60 kg/hm~2施氮量增加杂草密度和生物量;随氮肥施用量的增加,杂草的密度和生物量均显著降低。在180 kg/hm~2供氮量时,杂草的密度和生物量达到最低,分别比60 kg/hm~2施氮量的最大值下降81%～94%和90%,玉米产量达到最大。与180 kg/hm~2施氮量相比,进一步增加施氮量,玉米产量不增加,杂草的密度和生物量也不再减少。因此,从施肥经济效益和杂草防控两个方面结合考虑,该地区最优施肥量为180 kg/hm~2。 相似文献