Skeleton weed (Chondrilla juncea) in the Victorian Mallee. 5. Chemical fallowing

1971 ◽  
Vol 11 (50) ◽  
pp. 320
Author(s):  
GJ Wells

Skeleton weed is difficult to control on cultivated fallows during the summer and experiments were commenced in 1963 on the use of short-term residual herbicides for chemically fallowing infested land for wheatgrowing. Rates and times of application of simazine mixtures, a picloram/2,4-D mixture, an atrazine/amiltrole mixture, and fenac were tested. Compared with cultivated fallows, chemical fallowing increased wheat yields in four years out of six. The yield responses were associated with increased soil nitrate and soil moisture at sowing, reflecting the improved weed control by herbicides, particularly during the summer period. The effects of toxic residues from simazine and atrazine on the wheat crop were influenced by rate and time of application, rainfall during the fallow period, and soil type.

Author(s):  
M.B. O'Connor ◽  
P.E.H. Gregg

On twenty-four sites throughout the country the effect of time and rate of applied nitrogen on "out-of-season" pasture production was studied over two seasons (1969-70 and 1970-71). Responses to spring-applied nitrogen wem more reliable than to autumn-applied. Spring responses varied from slight (2-7 kg DM/kg N) in the Waik& o, Bay of Plenty and parts of Canterbury to very good (10-20 kg DM/kg N) in Taranati, Dannevirke, southern Wairarapa, northern South Island, Westland and parts of Southland. When yield responses are considered as a substitute for hay, or other supplementary feedstuffs, payable results occur above about 7 kg DM/kg N. Factors such as time of application, soil type, pasture composition and amount of nitrogen in the soil affected the response to applied nitrogen.


Weed Science ◽  
1983 ◽  
Vol 31 (6) ◽  
pp. 853-856 ◽  
Author(s):  
Orvin C. Burnside ◽  
David R. Carlson

Early-preplant herbicide application for uncultivated production of soybean [Glycine max(L.) Merr. ‘Williams’] slot-seeded into untilled oat (Avena sativaL. 'Stout’) stubble was studied. Foliar- and soil-active herbicides were applied to stubble of recently harvested oats to control weeds without tillage so that soil moisture could accumulate during the fallow period. The following spring, five herbicide treatments were applied 0, 2, 4, and 6 weeks prior to soybean planting as well as preemergence to control weeds selectively in uncultivated soybeans. Broadleaf weeds were more effectively controlled than grass weeds, but both were controlled adequately with several herbicide combinations and at all five application times. Selective control of weeds was sufficient to eliminate yield loss of uncultivated soybeans seeded into untilled oat stubble. This production method could provide the Great Plains soybean producer with an effective weed control system while conserving soil, soil moisture, labor, and fuel.


1968 ◽  
Vol 48 (3) ◽  
pp. 255-263 ◽  
Author(s):  
E. S. Molberg ◽  
J. R. Hay

Use of residual and contact herbicides was compared with cultivation for weed control on summerfallow on Regina heavy clay from 1964 to 1967, inclusive. A single spring application of desmetryne (2-isopropylamino-4-methylamino-6-methylthio-s-triazine) at 3 kg/ha gave 77 to 90% weed control without reducing wheat yields the following year. Disadvantages were incomplete weed control, and herbicide persistence in the soil with thinning of the following wheat crop in some years.Three or four applications of paraquat (1,1′-dimethyl-4,4-bipyridinium (salt)) at 1 kg/ha gave weed control equal to cultivation of summerfallow. Chemical summerfallow was equal to cultivated summerfallow in its effects on soil moisture conservation, NO3-N accumulation and crop yields. Chemical summerfallow conserved 91% of the original crop residues compared with 24% for cultivated summerfallow. This extra crop residue was sufficient to prevent serious soil erosion from wind. Paraquat is currently too expensive to compete with cultivation.


2021 ◽  
pp. 1-14
Author(s):  
Jodie A. Crose ◽  
Misha R. Manuchehri ◽  
Todd A. Baughman

Abstract Three herbicide premixes have recently been introduced for weed control in wheat. These include: halauxifen + florasulam, thifensulfuron + fluroxypyr, and bromoxynil + bicyclopyrone. The objective of this study was to evaluate these herbicides along with older products for their control of smallseed falseflax in winter wheat in Oklahoma. Studies took place during the 2017, 2018, and 2020 winter wheat growing seasons. Weed control was visually estimated every two weeks throughout the growing season and wheat yield was collected in all three years. Smallseed falseflax size was approximately six cm in diameter at time of application in all years. Control ranged from 96 to 99% following all treatments with the exception of bicyclopyrone + bromoxynil and dicamba alone, which controlled falseflax 90%. All treatments containing an acetolactate synthase (ALS)-inhibiting herbicide achieved adequate control; therefore, resistance is not suspected in this population. Halauxifen + florasulam and thifensulfuron + fluroxypyr effectively controlled smallseed falseflax similarly to other standards recommended for broadleaf weed control in wheat in Oklahoma. Rotational use of these products allows producers flexibility in controlling smallseed falseflax and reduces the potential for development of herbicide resistance in this species.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Katerina G. Tsakiri ◽  
Antonios E. Marsellos ◽  
Igor G. Zurbenko

Flooding normally occurs during periods of excessive precipitation or thawing in the winter period (ice jam). Flooding is typically accompanied by an increase in river discharge. This paper presents a statistical model for the prediction and explanation of the water discharge time series using an example from the Schoharie Creek, New York (one of the principal tributaries of the Mohawk River). It is developed with a view to wider application in similar water basins. In this study a statistical methodology for the decomposition of the time series is used. The Kolmogorov-Zurbenko filter is used for the decomposition of the hydrological and climatic time series into the seasonal and the long and the short term component. We analyze the time series of the water discharge by using a summer and a winter model. The explanation of the water discharge has been improved up to 81%. The results show that as water discharge increases in the long term then the water table replenishes, and in the seasonal term it depletes. In the short term, the groundwater drops during the winter period, and it rises during the summer period. This methodology can be applied for the prediction of the water discharge at multiple sites.


1966 ◽  
Vol 67 (2) ◽  
pp. 239-242
Author(s):  
Maurice Eddowes

Dinoseb and TCA were successfully used to control weeds in potatoes by Robertson (1960), and Wood, Sutherland & Stephens (1960). Since then many investigations have been carried out on the use of newer herbicides including the bipyridils, triazines and substituted ureas. The results of a number of these studies, presented at the Seventh British Weed Control Conference (1964), suggested that herbicides might give effective control of annual weeds in potatoes under a range of British conditions. Yields of marketable ware following herbicide treatment were similar, in general, to those obtained following standard post-planting cultivations, but occasionally the yields after herbicide treatment were either as much as 20% higher or lower than the controls. The performance of the herbicides was related mainly to weed flora, soil type and amount and distribution of rainfall.


1968 ◽  
Vol 48 (5) ◽  
pp. 535-544 ◽  
Author(s):  
A. R. Mack ◽  
W. S. Ferguson

Actual evapotranspiration (AE), soil moisture distribution, and moisture stress for a wheat crop (PE-AE) were estimated by the modulated soil moisture budget of Holmes and Robertson. The estimated soil moisture was reasonably well correlated with soil moisture measured weekly by means of gypsum blocks. Wheat yields from experimental plots in the corresponding area were related more closely to the moisture stress function (PE-AE: r = − 0.83), than to the seasonal precipitation (r = 0.62), the potential evapotranspiration (PE) or the evapotranspiration ratio (AE/PE). Regression analyses showed that the grain yields were reduced by an average of 156 (±sb = 40) kg/ha per cm of moisture stress from emergence to harvest, or by 311 and 69 kg/ha per cm of stress, from the fifth-leaf to the soft-dough stage and from the soft-dough stage to maturity, respectively. The moisture stress function may be used to characterize the soil–plant–atmosphere environment for the growing season of a crop. Precipitation and evapotranspiration data are presented annually for three standardized growing periods at Brandon from 1921 to 1963.


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