Effect of row spacing and herbicide dose on weed control and grain sorghum yield

2004 ◽  
Vol 23 (3) ◽  
pp. 263-267 ◽  
Author(s):  
W.James Grichar ◽  
Brent A. Besler ◽  
Kevin D. Brewer
1982 ◽  
Vol 22 (117) ◽  
pp. 310 ◽  
Author(s):  
JF Holland ◽  
DW McNamara

Six experiments were done in northern New South Wales over three seasons to study the effect of weeds on the yield of dry-land grain sorghum and methods of weed control. The relation between crop row spacing and weed control by inter-row cultivation or atrazine (2-chloro-4-ethylamino- 6-isopropylamino-l,3,5-triazine), or both was studied. Where the site yield was high because of favourable growing conditions, an increase in the crop row spacing reduced yield. At low yielding sites, an increase in the row spacing increased yields. At most sites, weed growth was greater with wider row spacings, which resulted in a larger reduction in crop yield where weeds were not removed. Inter-row cultivation reduced weed growth to less than half that of the unweeded controls. Pre-emergent atrazine gave good weed suppression, generally reducing weed growth to less than 10% of the unweeded control when applied at 2.5 kg/ha active ingredient. Post-emergent atrazine was much less effective. Inter-row cultivation combined with a band of pre-emergent atrazine over the crop row was as effective in weed control as an overall spray of pre-emergent atrazine.


1990 ◽  
Vol 129 (2) ◽  
pp. 117-120 ◽  
Author(s):  
U. R. Bishnoi ◽  
D. A. Mays ◽  
M. T. Fabasso

1990 ◽  
Vol 4 (2) ◽  
pp. 245-249 ◽  
Author(s):  
Brenda S. Smith ◽  
Don S. Murray ◽  
J. D. Green ◽  
Wan M. Wanyahaya ◽  
David L. Weeks

Barnyardgrass, large crabgrass, and Texas panicum were evaluated in field experiments over 3 yr to measure their duration of interference and density on grain sorghum yield. When grain yield data were converted to a percentage of the weed-free control, linear regression predicted a 3.6% yield loss for each week of weed interference regardless of year or grass species. Grain sorghum grown in a narrow (61-cm) row spacing was affected little by full-season interference; however, in wide (91-cm) rows, interference increased as grass density increased. Data from the wide-row spacing were described by linear regression following conversion of grain yield to percentages and weed density to log10. A separate nonlinear model also was derived which could predict the effect of weed density on grain sorghum yield.


Weed Science ◽  
1987 ◽  
Vol 35 (5) ◽  
pp. 695-699 ◽  
Author(s):  
Steven M. Brown ◽  
James M. Chandler ◽  
John E. Morrison

A field experiment was conducted to evaluate weed control systems in a conservation tillage rotation of grain sorghum [Sorghum bicolor(L.) Moench.] – cotton (Gossypium hirsutumL.) – wheat (Triticum aestivumL.). Herbicide systems included fall and spring/summer inputs of high and low intensity. Tillage regimes were no-till (NT) and reduced-till (RT) systems; the latter included fall primary tillage followed by spring stale seedbed planting. Both tillage systems utilized controlled traffic lanes and wide, raised beds. Effective johnsongrass [Sorghum halepense(L.) Pers. # SORHA] control required intense herbicide inputs at one or both application periods, i.e., in the fall and/or spring/summer. Grain sorghum and cotton yields for the most intense weed control system, which included high inputs in both the fall and spring/summer, were not superior to systems that included high inputs in only one of the two application periods. Seedling johnsongrass emergence occurred before spring planting in RT (but not in NT) in 2 of 3 yr, and control measures were ineffective. After 3 yr, the predominant weeds were johnsongrass and browntop panicum (Panicum fasciculatumSw. # PANFA).


2018 ◽  
Vol 32 (4) ◽  
pp. 364-370 ◽  
Author(s):  
Zachary D. Lancaster ◽  
Jason K. Norsworthy ◽  
Robert C. Scott

AbstractField experiments were conducted in 2014 and 2015 in Fayetteville, Arkansas, to evaluate the residual activity of acetyl-CoA carboxylase (ACCase)–inhibiting herbicides for monocot crop injury and weed control. Conventional rice, quizalofop-resistant rice, grain sorghum, and corn crops were evaluated for tolerance to soil applications of six herbicides (quizalofop at 80 and 160 g ai ha–1, clethodim at 68 and 136 g ai ha–1, fenoxaprop at 122 g ai ha–1, cyhalofop at 313 g ai ha–1, fluazifop at 210 and 420 g ai ha–1, and sethoxydim at 140 and 280 g ai ha–1). Overhead sprinkler irrigation of 1.3 cm was applied immediately after treatment to half of the plots, and the crops planted into the treated plots at 0, 7, and 14 d after herbicide treatment. In 2014, injury from herbicide treatments increased with activation for all crops evaluated, except for quizalofop-resistant rice. At 14 d after treatment (DAT) in 2014, corn and grain sorghum were injured 19% and 20%, respectively, from the higher rate of sethoxydim with irrigation activation averaged over plant-back dates. Conventional rice was injured 13% by the higher rate of fluazifop in 2014. Quizalofop-resistant rice was injured no more than 4% by any of the graminicides evaluated in either year. In 2015, a rainfall event occurred within 24 h of initiating the experiment; thus, there were no differences between activation via irrigation or by rainfall. However, as in 2014, grain sorghum and corn were injured 16% and 13%, respectively, by the higher rate of sethoxydim, averaged over plant-back dates. All herbicides provided little residual control of grass weeds, mainly broadleaf signalgrass and barnyardgrass. These findings indicate the need to continue allowing a plant-back interval to rice following a graminicide application, unless quizalofop-resistant rice is to be planted. The plant-back interval will vary by graminicide and the amount of moisture received following the application.


Author(s):  
K.R. Brown ◽  
M.P. Rolston ◽  
W.J. Archie

'Grasslands Wana' cocksfoot (Dactylis glomerata), a new cultivar, produced highest seed yields (405 kg/ha over three years) at 30 cm row spacing in Canterbury. Wider rows (45 and 60cm) produced more seed heads/m* but lower yields, whereas with 15 cm rows there were fewer seed heads and lower yields. In the Manawatu, Wana yields averaged 605 kg/ha over three years, although the North Island is not recognised as a cocksfoot seed producing area. Seed weights range from 0.65 to 0.85 g/l000 seeds, lighter than Apanui and Kara cocksfoots. With two autumn sowings, Wana produced 325 and 170 kg/ha 10 months after sowing. Controlling weeds, especially Poa annoa, is important for high yields from autumn sowings. Plots treated with ethofumesate yielded up to 7 times more than untreated plots. Management, fertiliser use, and rules for changing cocksfoot cultivars are discussed. Keywords: Dactylis glomerata, row spacing, weed control, ethofumesate, terbicil, nitrogen.


1989 ◽  
Vol 3 (4) ◽  
pp. 621-626 ◽  
Author(s):  
David L. Regehr ◽  
Keith A. Janssen

Research in Kansas from 1983 to 1986 evaluated early preplant (30 to 45 days) and late preplant (10 to 14 days) herbicide treatments for weed control before ridge-till planting in a soybean and sorghum rotation. Control of fall panicum and common lambsquarters at planting time averaged at least 95% for all early preplant and 92% for late preplant treatments. Where no preplant treatment was used, heavy weed growth in spring delayed soil dry-down, which resulted in poor ridge-till planting conditions and reduced plant stands, and ultimately reduced sorghum grain yields by 24% and soybean yields by 12%. Horsenettle population declined significantly, and honeyvine milkweed population increased. Smooth groundcherry populations fluctuated from year to year with no overall change.


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