Itchgrass (Rottboellia cochinchinensis) Control Options in Soybean (Glycine max)

1991 ◽  
Vol 5 (2) ◽  
pp. 426-429 ◽  
Author(s):  
James L. Griffin

In field studies trifluralin and pendimethalin at 1.7 kg ai ha-1applied PPI controlled itchgrass 87 and 78%, respectively, in late season when averaged over a 2-yr period. Clomazone at 1.1 kg ai ha-1applied PRE to the soil surface in one year controlled 80% of itchgrass compared with 51% when applied PPI. POST application of 0.15 kg ai ha-1fluazifop-P, 0.21 kg ai ha-1haloxyfop, 0.10 kg ai ha-1quizalofop, and 1.1 kg ai ha-1diclofop controlled at least 90%. Itchgrass control was less effective with 0.43 kg ai ha-1sethoxydim and 0.07 kg ai ha-1clethodim POST and poor with 0.15 kg ai ha-1imazaquin and 0.07 kg ai ha-1imazethapyr.

1982 ◽  
Vol 33 (1) ◽  
pp. 75 ◽  
Author(s):  
GM McKeon ◽  
JJ Mott

The changes in hard-seed content in pastures of Stylosanthes humilis and S. hamata cv. Verano were studied at Katherine, N.T. Both field studies and laboratory ovens with diurnal temperature changes showed that maximum soil surface temperatures greater than 50-55�C were required to produce substantial softening of hard seed. The rate of softening increased with higher maximum temperature. At Katherine, only the September-November period (late dry season) was likely to produce soil surface temperatures high enough for softening in naturally occurring seed populations. S. hamata did not soften to the same extent as S. humilis under both field and laboratory conditions. In established pastures only 35 % of S. hamata seed softened in one year, compared with 60-80% in S. humilis. Management practices may be required to improve seedling regeneration or establishment of new pastures in S. hamata.


1998 ◽  
Vol 12 (4) ◽  
pp. 677-683 ◽  
Author(s):  
José A. Noldin ◽  
James M. Chandler ◽  
Garry N. McCauley ◽  
John W. Sij

Field studies were conducted from 1992 to 1994 to evaluate herbicides applied preplant incorporated (PPI), preemergence (PRE), and postemergence (POST) for red rice andEchinochloaspp. control in soybean. Metolachlor PPI at 3.4 kg ai/ha controlled red rice late season 90 to 92%. Alachlor at 4.5 kg ai/ha and SAN 582H at 2.2 or 3.4 kg ai/ha, PPI or PRE, metolachlor plus imazaquin at 2.8 + 0.14 kg ai/ha PRE, and quizalofop-P POST at 0.07 kg ai/ha provided 83 to 95% red rice control in at least 2 of 3 yr. The addition of imazaquin to metolachlor or pendimethalin did not improve red rice control. Early-seasonEchinochloaspp. control with trifluralin, pendimethalin, and pendimethalin + imazaquin applied PPI; metolachlor, SAN 582H at 2.2 or 3.4 kg/ha, and metolachlor + imazaquin applied PPI or PRE; alachlor, AC 263,222 + imazaquin, and AC 263,222 + imazethapyr applied PRE; and sethoxydim and quizalofop-P applied POST was 90 to 100% in at least 2 of 3 yr. However,Echinochloaspp. control decreased for all treatments later in the season. Pendimethalin applied PPI at 2.2 kg ai/ha or in mixture with imazaquin at 1.7 + 0.14 kg ai/ha injured soybean 14 to 34% in 2 yr. Trifluralin PPI, SAN 582H at 2.2 or 3.4 kg/ha PPI or PRE, imazaquin PPI, metolachlor + imazaquin PPI or PRE, and AC 263,222 + imazethapyr injured soybean 12 to 41% in at least 1 of 3 yr.


1988 ◽  
Vol 2 (1) ◽  
pp. 24-27 ◽  
Author(s):  
Henry P. Wilson ◽  
Thomas E. Hines ◽  
Kriton K. Hatzios ◽  
J. Peyton Doub

In field studies conducted in 1984, 1985, and 1986, annual grass control by a microencapsulated (ME) formulation of alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] generally was greater than that by the emulsifiable concentrate (EC) in no-till and was comparable to EC-alachlor in conventionally tilled corn (Zea maysL.) and soybeans [Glycine max(L.) Merr.]. In 1986, ME-metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] controlled annual grass similar to EC-metolachlor. In greenhouse studies, shoot height and fresh weight of barnyardgrass [Echinochloa crus-galli(L.) Beauv. # ECHCG] sown in pots and treated with ME-alachlor was significantly greater than that treated with EC-alachlor. Soybean straw on the soil surface did not affect the differences between alachlor formulations in the greenhouse.


1995 ◽  
Vol 9 (2) ◽  
pp. 339-342 ◽  
Author(s):  
Donn G. Shilling ◽  
Barry J. Brecke ◽  
Clifton Hiebsch ◽  
Gregory MacDonald

Field studies were conducted to determine the effect of soybean cultivar, tillage, and rye mulch on sicklepod growth. Early-season sicklepod height was not affected by tillage or mulch. Sicklepod was tallest when grown with ‘Centennial’ or ‘Biloxi,’ the tallest cultivars, and shortest when grown with a dwarf isoline of ‘Tracy M,’ the shortest cultivar. Soybean competition reduced early-season weed density by 30 to 50%, depending on the cultivar. Centennial and dwarf Tracy M caused a 30% reduction in early-season sicklepod biomass while ‘Sharkey’ and Biloxi reduced sicklepod growth by 40%. By late-season, sicklepod biomass reduction ranged from 18% (Tracy M) to 55% (Biloxi) and was directly related to soybean cultivar height. Mulch or no-tillage independently reduced sicklepod biomass.


1993 ◽  
Vol 7 (1) ◽  
pp. 118-122 ◽  
Author(s):  
Teresa S. Willard ◽  
James L. Griffin

In field studies conducted over 2 yr, POST applications of chlorimuron, imazaquin, fomesafen, or acifluorfen following PRE applications of clomazone, metribuzin, or metribuzin plus chlorimuron enhanced wild poinsettia control when compared with the PRE herbicides applied alone. Wild poinsettia control was highest for imazaquin compared with other PRE treatments and with the exception of fomesafen, applications of POST herbicides following imazaquin PRE did not improve weed control. With the addition of POST herbicides, soybean yields were generally not increased, but moisture content in one year and foreign material content both years were reduced. In other studies, early POST applications (2 to 8 cm) of fomesafen, imazaquin, acifluorfen, lactofen, and chlorimuron controlled wild poinsettia better than late POST applications (10 to 15 cm) in only one year. Soybean yields both years were generally similar regardless of herbicide application time.


2011 ◽  
Vol 8 (1) ◽  
pp. 1043-1076
Author(s):  
A. Kammer ◽  
F. Hagedorn

Abstract. Very few field studies have quantified the different pathways of C loss from decomposing litter even though this is essential to better understand long-term dynamics of C stocks in soils. Using 13C-labelled leaf (isotope ratio (δ13C) = −40.8‰) and twig litter (δ13C = −38.4‰), we tracked down the litter-derived C in the soil respiration, in the dissolved organic C (DOC) and in the soil organic matter of a beech forest in the Swiss Jura. After one year of decomposition, mass loss in the litter layer was almost twice as great for leaves as it was for twigs (75% vs. 40%). This difference was not the result of a slow mineralisation of the woody litter, but primarily of the only slight incorporation of twig-derived C into mineral soils. The C mineralisation rates of the twig litter were only slightly lower than those of the leaf litter (10–35%), in particular after the loss of the readily available litter fraction. However, the leaching of DOC from twigs amounted only to half of that from leaves. Tracing the litter-derived DOC showed that DOC from both litter types was mostly retained (88–96%) and stabilised in the top centimetres of the mineral soil. In the soil organic C at 0–2 cm depth, we recovered 8% of the initial leaf C, but only 4% of the twig C. Moreover, the 13C mass balance suggested that a substantial fraction of the leaf material (~30%) was transported via soil fauna to soil depths below 2 cm, while the twig litter mainly decomposed in situ on the soil surface, probably due to its rigid structure and low nutritional value. In summary, our study shows that decaying twigs are rapidly mineralised, but seem to be clearly less important for the C storage in this beech forest soils than leaf litter.


1991 ◽  
Vol 5 (2) ◽  
pp. 396-399 ◽  
Author(s):  
Reed J. Lencse ◽  
James L. Griffin

Field studies were conducted in the northern and southern cane belt areas of Louisiana to determine the effect of itchgrass on sugarcane growth and yield. Itchgrass was allowed to interfere with sugarcane season-long, early-season from emergence in the spring until layby (last cultivation) in mid-June, and late-season from layby until harvest. Itchgrass germination occurred throughout the growing season. Populations of millable sugarcane stalks and yields of cane and sugar were similar for no interference, early-, and late-season interference. Season-long itchgrass interference reduced sugarcane stalk populations and cane and sugar yields an average of 34, 42, and 43%, respectively, compared with no interference.


2021 ◽  
Vol 11 (7) ◽  
pp. 2979
Author(s):  
Maxime Fortin Faubert ◽  
Dominic Desjardins ◽  
Mohamed Hijri ◽  
Michel Labrecque

The Salix genus includes shrub species that are widely used in phytoremediation and various other phytotechnologies due to their advantageous characteristics, such as a high evapotranspiration (ET) rate, in particular when cultivated in short rotation intensive culture (SRIC). Observations made in past field studies suggest that ET and its impact on soil hydrology can also lead to increases in soil pollutant concentrations near shrubs. To investigate this, sections of a mature willow plantation (seven years old) were cut to eliminate transpiration (Cut treatment). Soil concentrations of polychlorinated biphenyls (PCBs), aliphatic compounds C10–C50, polycyclic aromatic hydrocarbons (PAHs) and five trace elements (Cd, Cr, Cu, Ni and Zn) were compared between the Cut and the uncut plots (Salix miyabeana ‘SX61’). Over 24 months, the results clearly show that removal of the willow shrubs limited the contaminants’ increase in the soil surface, as observed for C10–C50 and of 10 PAHs under the Salix treatment. This finding strongly reinforces a hypothesis that SRIC of willows may facilitate the migration of contaminants towards their roots, thus increasing their concentration in the surrounding soil. Such a “pumping effect” in a high-density willow crop is a prominent characteristic specific to field studies that can lead to counterintuitive results. Although apparent increases of contaminant concentrations contradict the purification benefits usually pursued in phytoremediation, the possibility of active phytoextraction and rhizodegradation is not excluded. Moreover, increases of pollutant concentrations under shrubs following migration suggest that decreases would consequently occur at the source points. Some reflections on interpreting field work results are provided.


1989 ◽  
Vol 4 (4) ◽  
pp. 241-244
Author(s):  
P. Lemoine

SummaryIt is difficult to undertake field studies with non marketed psychotropic drugs because of two apparently contradictory conditions : on the one hand, the methodology has to be rigorously controlled, and on the other hand, such studies have to be carried out in their future environment by general practitioners (GPs). Bearing in mind the lack of training and experience regarding this kind of approach, the author adopted a discussion group method according to the techniques developed by M. Balint. The study group comprised five GPs, a clinical pharmacology expert and a doctor from the pharmaceutical laboratory which had developed the test drug. These persons met on a monthly basis over a one year period. In the present paper, the author indicates the benefits of such a methodology, based on six years’ experience and several trials, with special emphasis placed on the pedagogical aspects.


2013 ◽  
Vol 23 (2) ◽  
pp. 133-140 ◽  
Author(s):  
Xiaowen Hu ◽  
Tingshan Li ◽  
Juan Wang ◽  
Yanrong Wang ◽  
Carol C. Baskin ◽  
...  

AbstractAlthough seed dormancy of temperate legumes is well understood, less is known about it in species that grow in subalpine/alpine areas. This study investigated dormancy and germination of four Vicia species from the Tibetan Plateau. Fresh seeds of V. sativa were permeable to water, whereas those of V. angustifolia, V. amoena and V. unijuga had physical dormancy (PY). One year of dry storage increased the proportion of impermeable seeds in V. angustifolia, but showed no effect on seed coat permeability in V. amoena or V. unijuga. Seeds of all four species also had non-deep physiological dormancy (PD), which was especially apparent in the two annuals at a high germination temperature (20°C). After 1 year of storage, PD had been lost. The hydrotime model showed that fresh seeds obtained a significantly higher median water potential [Ψb(50)] than stored seeds, implying that PD prevents germination in winter for seeds dispersed without PY when water availability is limited. After 6 months on the soil surface in the field, a high proportion of permeable seeds remained ungerminated, further suggesting that PD plays a key role in preventing germination after dispersal. Addition of fluridone, an inhibitor of abscisic acid (ABA) biosynthesis, evened-out the differences in germination between fresh and stored seeds, which points to the key role of ABA biosynthesis in maintaining dormancy. Further, fresh seeds were more sensitive to exogenous ABA than stored seeds, indicating that storage decreased embryo sensitivity to ABA. On the other hand, the gibberellic acid GA3 increased germination rate, which implies that embryo sensitivity to GA is also involved in seed dormancy regulation. This study showed that PY, PD or their combination (PY+PD) plays a key role in timing germination after dispersal, and that different intensities of dormancy occur among these four Vicia species from the Tibetan Plateau.


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