Sorghum Accessions for Use as Cover Crops and Biofuel Feedstocks

Phenotypes of sorghum species (Sorghum sp.) have characteristics making them valuable summer annual cover crops and/or biofuel feedstocks for temperate climates. In field studies conducted at Urbana, IL, USA, fourteen USDA sorghum landrace accessions and three commercial sorghum accessions were evaluated for their growth habits and regrowth potential. In Canonical Discriminant Analysis (CDA) analysis, the first two canonical variates were significant and accounted for 86% of the among-accession variability. Unmown tiller number, regrowth tiller number, and regrowth biomass best discriminated between accessions in CDA and scattergrams. The accessions clustered into three subgroups. Three multi-stemmed accessions (two commercial varieties and one USDA accession) with an ability to regrow clustered away from the bulk of the USDA sorghums. Multi-stemmed accessions are useful for breeding improved summer annual cover crops that are tall, produce copious amounts of biomass, and rapidly regrow after defoliation; although propensity to lodging and poor germination of accessions will need attention. Additionally, landrace sorghum accessions in the USDA germplasm collection are useful for breeding cover crop and biofuel feedstocks, due to their great height and biomass production, although it will be necessary to select for improved regrowth potential. Crosses between USDA landraces and the commercially available multi-stemmed accessions could lead to a sorghum cover crop and biofuel plant with great biomass and height and ability to regrow following defoliation.

Download Full-text

Evaluation of crisphead lettuce cultivars in different cover types by manova and discriminant analysis

Horticultura Brasileira ◽

10.1590/s0102-05362013000300015 ◽

2013 ◽

Vol 31 (3) ◽

pp. 439-444

Author(s):

Izabela Regina C de Oliveira ◽

Marcelo T Rezende ◽

Carlos Tadeu dos S Dias ◽

Daniela de S Gomes ◽

Élberis P Botrel ◽

...

Keyword(s):

Discriminant Analysis ◽

Cover Crops ◽

Environmental Sustainability ◽

Cover Crop ◽

Univariate Analysis ◽

Polyethylene Film ◽

Standard Errors ◽

Multivariate Techniques ◽

Discriminant Analyses ◽

Plot Design

In many agricultural experiments the variables are biologically correlated and it is inappropriate to study them only under univariate analysis. Therefore, we evaluated commercial characteristics of crisphead lettuce cultivars and covers under a multivariate approach, using canonical discriminant analysis. We used a split plot design and we tested the cover crop, cultivar and interaction effects by using MANOVA (α= 5%). Means and its standard errors were obtained for average total weight, weight of the head, volume and density of plants. Canonical discriminant analyses were performed using PROC CANDISC procedure in SAS (SAS Institute, 2008) system. Canonical plots were obtained using JMP 9.0 (SAS Institute, 2010) linked to SAS database. With these plots it was possible to note the differences among factors levels. When polyethylene film was used as cover the plants had inferior commercial characteristics than plants in which cover crops were used. Thus, the cover with polyethylene film can be discouraged in the cultivation of crisphead lettuce, promoting environmental sustainability. We suggest these multivariate techniques in horticulture studies.

Download Full-text

Influence of legume cover crops and conservation tillage on soil populations of selected fungal genera

Canadian Journal of Microbiology ◽

10.1139/m88-038 ◽

1988 ◽

Vol 34 (3) ◽

pp. 201-206 ◽

Cited By ~ 9

Author(s):

C. S. Rothrock ◽

W. L. Hargrove

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Conservation Tillage ◽

Field Studies ◽

Macrophomina Phaseolina ◽

Hairy Vetch ◽

Fusarium Spp ◽

Crimson Clover ◽

Legume Cover Crops ◽

Legume Cover Crop

The influence of winter legume cover crops and of tillage on soil populations of fungal genera containing plant pathogenic species in the subsequent summer sorghum crop were examined in field studies. Legume cover crops significantly increased populations of Pythium spp. throughout the sorghum crop compared with a rye cover crop or no cover crop. This stimulation of the populations of Pythium spp. was not solely due to colonization of cover-crop residue, as populations were significantly greater at the time the legume cover crop was desiccated. Removal of aboveground residue generally decreased populations of Pythium spp. in soil. Incorporation of residue by tillage increased populations of Pythium spp. at some sampling dates. Legumes differed in the magnitude of stimulation, with hairy vetch stimulating Pythium spp. more than crimson clover. Cover crop treatments did not consistently influence soil populations of Fusarium spp., Rhizoctonia solani, Rhizoctonia-like binucleate fungi, or Macrophomina phaseolina. Macrophomina phaseolina populations were significantly greater under no tillage.

Download Full-text

Integration of residual herbicides with cover crop termination in soybean

Weed Technology ◽

10.1017/wet.2019.111 ◽

2019 ◽

Vol 34 (1) ◽

pp. 11-18 ◽

Cited By ~ 2

Author(s):

Derek M. Whalen ◽

Lovreet S. Shergill ◽

Lyle P. Kinne ◽

Mandy D. Bish ◽

Kevin W. Bradley

Keyword(s):

Weed Control ◽

Cover Crops ◽

Cover Crop ◽

Biomass Accumulation ◽

Field Studies ◽

Italian Ryegrass ◽

Cereal Rye ◽

Herbicide Treatments ◽

Residual Herbicide ◽

Herbicide Programs

AbstractCover crops have increased in popularity in midwestern U.S. corn and soybean systems in recent years. However, little research has been conducted to evaluate how cover crops and residual herbicides are effectively integrated together for weed control in a soybean production system. Field studies were conducted in 2016 and 2017 to evaluate summer annual weed control and to determine the effect of cover crop biomass on residual herbicide reaching the soil. The herbicide treatments consisted of preplant (PP) applications of glyphosate plus 2,4-D with or without sulfentrazone plus chlorimuron at two different timings, 21 and 7 d prior to soybean planting (DPP). Cover crops evaluated included winter vetch, cereal rye, Italian ryegrass, oat, Austrian winter pea, winter wheat, and a winter vetch plus cereal rye mixture. Herbicide treatments were applied to tilled and nontilled soil without cover crop for comparison. The tillage treatment resulted in low weed biomass at all collection intervals after both application timings, which corresponded to tilled soil having the highest sulfentrazone concentration (171 ng g−1) compared with all cover crop treatments. When applied PP, herbicide treatments applied 21 DPP with sulfentrazone had greater weed (93%) and waterhemp (89%) control than when applied 7 DPP (60% and 69%, respectively). When applied POST, herbicide treatments with a residual herbicide resulted in greater weed and waterhemp control at 7 DPP (83% and 77%, respectively) than at 21 DPP (74% and 61%, respectively). Herbicide programs that included a residual herbicide had the highest soybean yields (≥3,403 kg ha−1). Results from this study indicate that residual herbicides can be effectively integrated either PP or POST in conjunction with cover crop termination applications, but termination timing and biomass accumulation will affect the amount of sulfentrazone reaching the soil.

Download Full-text

Herbicide selection to terminate grass, legume, and brassica cover crop species

Weed Technology ◽

10.1017/wet.2019.107 ◽

2019 ◽

Vol 34 (1) ◽

pp. 48-54

Author(s):

Kara B. Pittman ◽

Charles W. Cahoon ◽

Kevin W. Bamber ◽

Lucas S. Rector ◽

Michael L. Flessner

Keyword(s):

Active Ingredient ◽

Cover Crops ◽

Cover Crop ◽

Field Studies ◽

Weed Suppression ◽

Hairy Vetch ◽

Crop Species ◽

Rating Data ◽

Crimson Clover ◽

And Control

AbstractCover crops provide a number of agronomic benefits, including weed suppression, which is important as cases of herbicide resistance continue to rise. To effectively suppress weeds, high cover crop biomass is needed, which necessitates later termination timing. Cover crop termination is important to mitigate potential planting issues and prevent surviving cover crop competition with cash crops. Field studies were conducted in Virginia to determine the most effective herbicide options alone or combined with glyphosate or paraquat to terminate a range of cover crop species. Results revealed that grass cover crop species were controlled (94% to 98%) by glyphosate alone 4 wk after application (WAA). Overall, legume species varied in response to the single active-ingredient treatments, and control increased with the addition of glyphosate or paraquat. Mixes with glyphosate provided better control of crimson clover and hairy vetch by 7% to 8% compared with mixes containing paraquat 4 WAA. Mix partner did not influence control of Austrian winter pea. No treatment adequately controlled rapeseed in this study, with a maximum of 58% control observed with single active-ingredient treatments and 62% control with mixes. Height reduction for all cover crop species supports visible rating data. Rapeseed should be terminated when smaller, which could negate weed suppressive benefits from this cover crop species. Growers should consider herbicide selection and termination timing in their cover crop plan to ensure effective termination.

Download Full-text

Preplant-Postemergence Herbicides for Legume Cover-Crop Control in Minimum Tillage Systems

Weed Technology ◽

10.1017/s0890037x00025495 ◽

1990 ◽

Vol 4 (2) ◽

pp. 332-336 ◽

Cited By ~ 13

Author(s):

James L. Griffin ◽

Seth M. Dabney

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Subterranean Clover ◽

Field Studies ◽

Application Time ◽

Hairy Vetch ◽

Crimson Clover ◽

Legume Cover Crops ◽

Legume Cover Crop ◽

Postemergence Herbicides

Field studies were conducted to compare preplant-postemergence-applied paraquat, glyphosate, SC-0224, and HOE-39866 on subterranean clover, crimson clover, and hairy vetch cover crops. Subterranean clover control with paraquat at 1.1 kg ai/ha was about 80 and 100% when applied in early April and early May, respectively, regardless of spray volume (190 vs. 370 L/ha). Glyphosate and SC-0224 at 1.7 and 2.8 kg ai/ha applied in April controlled about 53% of subterranean clover. Subterranean clover control with HOE-39866 at 0.8 kg ai/ha applied in April was excellent. Paraquat at 0.6 kg ai/ha and HOE-39866 at 0.8 kg/ha regardless of application time controlled both crimson clover and hairy vetch. Grain sorghum and soybean yields following the legume cover crops generally were similar for the herbicide treatments.

Download Full-text

Conservation cotton production in the southern United States: herbicide dissipation in soil and cover crops

Weed Science ◽

10.1614/ws-04-174r1.1 ◽

2005 ◽

Vol 53 (5) ◽

pp. 717-727 ◽

Cited By ~ 16

Author(s):

Martin A. Locke ◽

Robert M. Zablotowicz ◽

Philip J. Bauer ◽

R. Wade Steinriede ◽

Lewis A. Gaston

Keyword(s):

South Carolina ◽

Cover Crops ◽

Cover Crop ◽

Crop Residues ◽

Soil Surface ◽

Field Studies ◽

Cotton Field ◽

Reduced Tillage ◽

Cotton Production ◽

Conventional Ct

Soil and surface residues from cotton field studies in Stoneville, MS (1994 through 1996) and Florence, SC (1995 through 1996) were sampled to evaluate effects of cover crop and tillage on herbicide dissipation. Mississippi treatments included tillage (conventional [CT]; none [NT]) and cover crop (ryegrass; none [NC]). South Carolina treatments included tillage (CT; reduced tillage [RT]) and cover crop (rye; NC). Fluometuron was applied preemergence (PRE) in both Mississippi and South Carolina, and norflurazon was applied PRE in Mississippi. Soils were sampled various times during the growing season (depths: 0 to 2 cm, 2 to 10 cm). Cover crop residues were sampled from RT or NT cover crop areas. Soil and cover crop sample extracts were analyzed for herbicides. Soil organic carbon tended to increase with tillage reduction and presence of cover crop and was positively correlated with herbicide sorption, especially in the surface. Across locations, herbicide half-lives ranged from 7 to 15 d in the soil surface. Tillage had mixed effects on herbicide persistence in surface soil, with higher herbicide concentrations in CT at early samplings, but differences were insignificant later on. The most consistent effects were observed in RT/NT with cover crops, where cover crop residues intercepted applied herbicide, impeding subsequent movement into soil. Herbicide dissipation in cover crop residues was often more rapid than in soil, with half-lives from 3 to 11 d. Herbicide retention in cover crop residues and rapid dissipation were attributed to strong herbicide affinity to cover crop residues (e.g., fluometuron Kd= 7.1 [in rye]; Kd= 1.65 [in Mississippi Dundee soil CT, NC]) and herbicide co-metabolism as cover crop residues decomposed. A fluometuron metabolite, desmethyl-fluometuron, was observed in most soil and cover crop samples after 1 wk. Only minimal herbicide or metabolite moved into the subsurface, and little treatment effect could be ascribed to herbicide or metabolite movement below 2 cm.

Download Full-text

Field Studies on the Effect of Rye Cover Crop on Soybean Root Disease and Productivity

PhytoFrontiers™ ◽

10.1094/phytofr-05-21-0038-r ◽

2021 ◽

Author(s):

Grazieli Araldi Da Silva ◽

Gang Han ◽

Yuba Raj Kandel ◽

Daren S. Mueller ◽

Matthew Helmers ◽

...

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Cropping Systems ◽

Dry Weight ◽

Field Studies ◽

Winter Rye ◽

Canopy Reflectance ◽

Root Diseases ◽

Shoot Dry Weight ◽

Secale Cereale L

Cover crops improve soil and water quality in annual cropping systems, but knowledge of their impact on soybean (Glycine max L.) seedling and root diseases is limited. The effects of winter rye cover crops (Secale cereale L.) on soybean population, biomass, root morphology, seedling and root diseases, pathogen incidence, canopy reflectance, and yield were assessed over two years in Iowa and Missouri, USA. Plots without a rye cover crop were compared to plots with early-kill rye and late-kill rye cover crops, which were terminated 34 to 49 days or 5 to 17 days before soybean planting, respectively. Soybean shoot dry weight, root rot severity, and incidence of Fusarium spp. and Pythium spp. on roots were not influenced by the treatments. Soybean grain yield and plant population were reduced in the presence of rye in two site-years, increased in one site-year, and not changed in the remaining site-years. Soybean canopy reflectance was measured at 810 nm and measurements were first made at 70 to 80 days after planting (DAP). At least five measurements were obtained at 7- to 15- day intervals, ending at 120 to 125 DAP. Measurements at approximately 120 to 125 DAP differed by treatments but were not consistently associated with the presence or absence of a rye cover crop. Our field studies suggest that Iowa and Missouri soybean farmers can use winter rye as a cover crop in soybean fields with low seedling disease pressure without increasing the risk of seedling and root diseases or suppressing yield.

Download Full-text

Brassica cover cropping: II. Effects on growth and interference of green bean (Phaseolus vulgaris) and redroot pigweed (Amaranthus retroflexus)

Weed Science ◽

10.1614/ws-04-163r.1 ◽

2005 ◽

Vol 53 (5) ◽

pp. 702-708 ◽

Cited By ~ 15

Author(s):

Erin R. Haramoto ◽

Eric R. Gallandt

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Field Studies ◽

Companion Paper ◽

Amaranthus Retroflexus ◽

Green Bean ◽

Growth And Yield ◽

Yellow Mustard ◽

Redroot Pigweed ◽

Density And Biomass

Field studies have shown that weed density and biomass were lower in crops following incorporation of brassica cover crops compared with fallow but have not determined whether weed-suppressive effects are solely a consequence of reduced establishment, as evidenced in our companion paper, reduced growth of established plants, or both. In 2002 and 2003, canola and yellow mustard were seeded in early May, mowed in early July, and the residues incorporated. Green bean and redroot pigweed were then planted at fixed densities. Plant height and biomass were measured weekly; leaf area and biomass of component plant parts were measured at three harvests. Based on analysis of variance (ANOVA) at discreet sampling points, growth of redroot pigweed and green bean in monoculture or mixture were similar following fallow and incorporated brassica cover crops. However, based on aboveground biomass fitted to a Richards function, redroot pigweed growth in monoculture was reduced by the yellow mustard cover crop compared with fallow in both years (P = 0.007), but the magnitude of this effect was small; the canola cover crop did not affect growth (P = 0.179). Brassica cover crops did not reduce redroot pigweed growth when it was grown in mixture with green bean (P ≥ 0.382). Redroot pigweed competition reduced green bean yield, but incorporated brassica cover crops did not affect green bean growth and yield, nor did they confer a competitive advantage to the crop. Thus, brassica cover crops may suppress the growth of established weed and crop plants, but the magnitude of suppression was less than previously documented for effects on weed establishment.

Download Full-text

Herbicide carryover to various fall-planted cover crop species

Weed Technology ◽

10.1017/wet.2019.79 ◽

2019 ◽

Vol 34 (1) ◽

pp. 25-34

Author(s):

Lucas S. Rector ◽

Kara B. Pittman ◽

Shawn C. Beam ◽

Kevin W. Bamber ◽

Charles W. Cahoon ◽

...

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Field Studies ◽

Grass Cover ◽

Crop Species ◽

Visible Injury ◽

Cereal Rye ◽

Crimson Clover ◽

Crop Planting ◽

Crop Biomass

AbstractResidual herbicides applied to summer cash crops have the potential to injure subsequent winter annual cover crops, yet little information is available to guide growers’ choices. Field studies were conducted in 2016 and 2017 in Blacksburg and Suffolk, Virginia, to determine carryover of 30 herbicides commonly used in corn, soybean, or cotton on wheat, barley, cereal rye, oats, annual ryegrass, forage radish, Austrian winter pea, crimson clover, hairy vetch, and rapeseed cover crops. Herbicides were applied to bare ground either 14 wk before cover crop planting for a PRE timing or 10 wk for a POST timing. Visible injury was recorded 3 and 6 wk after planting (WAP), and cover crop biomass was collected 6 WAP. There were no differences observed in cover crop biomass among herbicide treatments, despite visible injury that suggested some residual herbicides have the potential to effect cover crop establishment. Visible injury on grass cover crop species did not exceed 20% from any herbicide. Fomesafen resulted in the greatest injury recorded on forage radish, with greater than 50% injury in 1 site-year. Trifloxysulfuron and atrazine resulted in greater than 20% visible injury on forage radish. Trifloxysulfuron resulted in the greatest injury (30%) observed on crimson clover in 1 site-year. Prosulfuron and isoxaflutole significantly injured rapeseed (17% to 21%). Results indicate that commonly used residual herbicides applied in the previous cash crop growing season result in little injury on grass cover crop species, and only a few residual herbicides could potentially affect the establishment of a forage radish, crimson clover, or rapeseed cover crop.

Download Full-text

The effects of integrating a cereal rye cover crop with herbicides on glyphosate-resistant horseweed (Conyza canadensis) in no-till soybean

Weed Science ◽

10.1017/wsc.2020.47 ◽

2020 ◽

Vol 68 (5) ◽

pp. 527-533

Author(s):

Alyssa I. Essman ◽

Mark M. Loux ◽

Alexander J. Lindsey ◽

Anthony F. Dobbels ◽

Emilie E. Regnier

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Plant Density ◽

Field Studies ◽

Planting Date ◽

Conyza Canadensis ◽

Seeding Rate ◽

Cereal Rye ◽

No Till ◽

Herbicide Treatment

AbstractCurrent recommendations for the control of glyphosate-resistant horseweed [Conyza canadensis (L.) Cronquist var. canadensis] in soybeans [Glycine max (L.) Merr.] consist of comprehensive herbicide programs, which often include herbicide applications outside the soybean growing season. Integration of cover crops with herbicides could potentially improve C. canadensis control and allow for a reduction in herbicide inputs. Two separate field studies were conducted from 2016 through 2018 with the objectives of: (1) determining the effect of planting date and seeding rate of a cereal rye (Secale cereale L.) cover crop on C. canadensis population density and control in the subsequent soybean crop; and (2) determining whether the cover crop could replace a fall herbicide treatment or allow for a reduction in the use of spring-applied residual herbicides. There was no effect of rye planting date, late September versus late October, on C. canadensis density in either study. In 2016 to 2017, C. canadensis density was greater in the absence of a rye cover crop in both studies, but otherwise not affected by seeding rates of 50 versus 100 kg ha−1. In the 2017 to 2018 season, the presence of rye resulted in an increased C. canadensis density in the spring residual herbicide study (Study I), and had no effect in the fall herbicide study (Study II). Conyza canadensis densities were lowest in the treatments where a comprehensive spring residual or fall herbicide treatment had been applied, averaged over rye planting date and seeding rate. Earlier-planted rye at a higher seeding rate produced the most biomass but did not result in lower C. canadensis densities. These results suggest that cereal rye planted at a density of 50 kg ha−1 as a cover crop before no-till soybeans may be sufficient to reduce glyphosate-resistant C. canadensis plant density, but cannot be relied upon to reduce the need for fall herbicide treatments and spring residual programs.

Download Full-text