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

Weed Science ◽  
2005 ◽  
Vol 53 (5) ◽  
pp. 717-727 ◽  
Author(s):  
Martin A. Locke ◽  
Robert M. Zablotowicz ◽  
Philip J. Bauer ◽  
R. Wade Steinriede ◽  
Lewis A. Gaston

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.

1995 ◽  
Vol 10 (4) ◽  
pp. 157-162 ◽  
Author(s):  
N.G. Creamer ◽  
B. Plassman ◽  
M.A. Bennett ◽  
R.K. Wood ◽  
B.R. Stinner ◽  
...  

AbstractResidues of dead cover crops can suppress weeds by providing a mulch on the soil surface. The cover crop usually is killed with herbicides, but a mechanical method is desirable in systems intended to reduce chemical use. We designed and built an undercutter to kill cover crops by severing their roots while flattening the intact aboveground biomass on the surface of raised beds. We studied which cover crop species could be killed with the undercutter and compared the weed control potential of cover crop residues after flail mowing, sicklebar mowing, and undercutting.Whether a species was killed by the undercutter depended primarily on growth stage. Species that were in mid- to late bloom or beyond, including rye, hairy vetch, bigflower vetch, crimson clover, barley, and subterranean clover, were easily killed by undercutting. There were no differences in dry weights of broadleaf weeds between the undercut and simulated sicklebar mowed treatments, both of which had less weed biomass than the clean-tilled or flail-mowed plots.


2018 ◽  
Vol 34 (6) ◽  
pp. 492-500 ◽  
Author(s):  
Alireza Safahani Langeroodi ◽  
Emanuele Radicetti ◽  
Enio Campiglia

AbstractIn the conventional cropping systems, increased costs and resource pollution are attributed to the intensive use of chemical inputs. The adoption of cover crops could be a part of a suitable strategy for improving the sustainability of the agro-ecosystems due to their ability to affect nutrient and weed management. A 2-yr field experiments were conducted in Gorgan, North of Iran, with the aim of assessing the effect of cover crop residue management and herbicide rates on weed management and the yield of tomato crop. The treatments consisted in: (a) three winter soil management: two cover crops [annual medic (Medicago scutellata L.) and barley (Hordeum vulgare L.)] and no covered soil; (b) two soil tillage (no-tillage, where cover crop residues were left in strips on the soil surface, and conventional tillage, where cover crop residues were green manured at 30 cm of soil depth); and (c) three pre-emergence herbicide rates (no-herbicide application, half rate recommended or full rate recommended ). Cover crops were sown in early September and mechanically suppressed in March about 2 weeks before tomato transplanting. At cover crop suppression, annual medic showed the highest aboveground biomass [569 g m−2 of dry matter (DM)], while barley showed the lowest weed content (32 g m−2 of DM). At tomato harvesting, weed density and aboveground biomass ranged from 6.9 to 61.5 plants m−2 and from 33.6 and 1157.0 g m−2 of DM, respectively. Cover crop residues placed on soil surface suppressed weeds more effectively than incorporated residues, especially in barley, mainly due to the physical barrier of residues which reduced the stimulation of weed germination and establishment. As expected, herbicide rate decreased both weed density and biomass, even if the adoption of annual medic and barley cover crops before the tomato cultivation could allow a possible reduction of herbicide rate while maintaining similar fruit yield. Tomato yield was higher in annual medic than barley and no cover regardless of tillage management (on average 62.3, 51.8 and 50.1 t ha−1 of fresh matter, respectively) probably due to an abundant availability of soil nitrogen throughout the tomato cultivation. This was confirmed by high and constant values of tomato N status grown in annual medic and evaluated using SPAD chlorophyll meter. Although further research of cover crop residue management is required to obtain a better understanding on herbicide rate reduction, these preliminary results could be extended to other vegetable crops which have similar requirements of tomato.


2017 ◽  
Vol 32 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Matheus G. Palhano ◽  
Jason K. Norsworthy ◽  
Tom Barber

AbstractWith the recent confirmation of protoporphyrinogen oxidase (PPO)-resistant Palmer amaranth in the US South, concern is increasing about the sustainability of weed management in cotton production systems. Cover crops can help to alleviate this problem, as they can suppress weed emergence via allelochemicals and/or a physical residue barrier. Field experiments were conducted in 2014 and 2015 at the Arkansas Agricultural Research and Extension Center to evaluate various cover crops for suppressing weed emergence and protecting cotton yield. In both years, cereal rye and wheat had the highest biomass production, whereas the amount of biomass present in spring did not differ among the remaining cover crops. All cover crops initially diminished Palmer amaranth emergence. However, cereal rye provided the greatest suppression, with 83% less emergence than in no cover crop plots. Physical suppression of Palmer amaranth and other weeds with cereal residues is probably the greatest contributor to reducing weed emergence. Seed cotton yield in the legume and rapeseed cover crop plots were similar when compared with the no cover crop treatment. The seed cotton yield collected from cereal cover crop plots was lower than from other treatments due to decreased cotton stand.


2004 ◽  
Vol 47 (3) ◽  
pp. 381-386 ◽  
Author(s):  
Júlio C. Franchini ◽  
Marcos A. Pavan ◽  
Mário Miyazawa

The objective of this study was to evaluate if cover crops can absorb P from the upper layers and transport it in their roots to subsoil layers. Samples of an Oxisol were placed in PVC columns. Super phosphate fertilizer was applied to the 0-10 cm soil surface layers. The cover crops tested were: Avena strigosa, Avena sativa, Secale cereale, Pisum sativum subsp arvense, Pisum sativum, Vicia villosa, Vicia sativa, Lupinus angustifoliu, Lupinus albus, and Triticum aestivum. After a growth period of 80 days the cover crop shoots were cut off and the soil was divided into 10cm layers and the roots of each layer were washed out. The roots and shoots were analyzed separated for total P contribution to the soil. Considerable amount of P was present in the roots of cover crops. Vicia sativa contained more than 60% of total plant P in the roots. The contribution of Vicia sativa to soil P bellow the fertilized zone was about 7 kg ha-1. It thus appeared that there existed a possibility of P redistribution into the soil under no tillage by using cover crops in rotation with cash crops. Vicia sativa was the most efficient cover crop species as P carrier into the roots from superficial layer to lower layers.


1988 ◽  
Vol 34 (3) ◽  
pp. 201-206 ◽  
Author(s):  
C. S. Rothrock ◽  
W. L. Hargrove

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.


2007 ◽  
Vol 64 (2) ◽  
pp. 181-186 ◽  
Author(s):  
Kipling Shane Balkcom ◽  
Charles Wesley Wood ◽  
James Fredrick Adams ◽  
Bernard Meso

Leguminous winter cover crops have been utilized in conservation systems to partially meet nitrogen (N) requirements of succeeding summer cash crops, but the potential of summer legumes to reduce N requirements of a winter annual grass, used as a cover crop, has not been extensively examined. This study assessed the N contribution of peanut (Arachis hypogaea L.) residues to a subsequent rye (Secale cereale L.) cover crop grown in a conservation system on a Dothan sandy loam (fine-loamy, kaolinitic, thermic Plinthic Kandiudults) at Headland, AL USA during the 2003-2005 growing seasons. Treatments were arranged in a split plot design, with main plots of peanut residue retained or removed from the soil surface, and subplots as N application rates (0, 34, 67 and 101 kg ha-1) applied in the fall. Peanut residue had minimal to no effect on rye biomass yields, N content, carbon (C) /N ratio, or N, P, K, Ca and Zn uptake. Additional N increased rye biomass yield, and N, P, K, Ca, and Zn uptakes. Peanut residue does not contribute significant amounts of N to a rye cover crop grown as part of a conservation system, but retaining peanut residue on the soil surface could protect the soil from erosion early in the fall and winter before a rye cover crop grows sufficiently to protect the typically degraded southeastern USA soils.


2015 ◽  
Vol 3 (2) ◽  
pp. 258
Author(s):  
Abram Jared Bicksler ◽  
John B Masiunas

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.


2022 ◽  
pp. 112-120
Author(s):  
Jeffrey P. Mitchell ◽  
Anil Shrestha ◽  
Lynn Epstein ◽  
Jeffery A. Dahlberg ◽  
Teamrat Ghezzehei ◽  
...  

To meet the requirements of California's Sustainable Groundwater Management Act, there is a critical need for crop production strategies with less reliance on irrigation from surface and groundwater sources. One strategy for improving agricultural water use efficiency is reducing tillage and maintaining residues on the soil surface. We evaluated high residue no-till versus standard tillage in the San Joaquin Valley with and without cover crops on the yields of two crops, garbanzo and sorghum, for 4 years. The no-till treatment had no primary or secondary tillage. Sorghum yields were similar in no-till and standard tillage systems while no-till garbanzo yields matched or exceeded those of standard tillage, depending on the year. Cover crops had no effect on crop yields. Soil cover was highest under the no-till with cover crop system, averaging 97% versus 5% for the standard tillage without cover crop system. Our results suggest that garbanzos and sorghum can be grown under no-till practices in the San Joaquin Valley without loss of yield.


2019 ◽  
Vol 34 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Derek M. Whalen ◽  
Lovreet S. Shergill ◽  
Lyle P. Kinne ◽  
Mandy D. Bish ◽  
Kevin W. Bradley

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.


Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 372
Author(s):  
Lucas Clay ◽  
Katharine Perkins ◽  
Marzieh Motallebi ◽  
Alejandro Plastina ◽  
Bhupinder Singh Farmaha

Cover crops are becoming more accepted as a viable best management practice because of their ability to provide important environmental and soil health benefits. Because of these benefits, many land managers are strongly encouraging the use of cover crops. Additionally, there is limited information on farmers′ perceptions of the benefits and challenges of implementing cover crops. Many farmers state that they do not have enough money or time to implement cover crops. In an attempt to gather more data about the adoption rate and perceptions of cover crops in South Carolina, a survey was sent to 3000 row crop farmers across the state. Farmers were asked whether they implement cover crops and their perceptions of the benefits and challenges associated with implementation. Furthermore, questions were asked regarding the impact of row cropping on their environment to gauge farmer′s education level on environmental impacts. Responses showed many people are implementing cover crops; however, there are still differences in perceptions about benefits and challenges between those who are adopting cover crops and those who are not. This research assesses these differences and aims to provide a baseline for focusing cover crop programs to tackle these certain challenges and promote the benefits.


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