Sorghum fallow

Phillips, W.M. (1964b). A new technique of controlling weeds in sorghum in a wheat-sorghum-fallow rotation in the Great Plains. 

Wicks, G.A., C.R. Fenster, and O.C. Burnside (1969). Herbicide residue in soil when applied to sorghum in a winter wheat-sorghum-fallow rotation. Agron. J., 61 721-724. 

In subsequent years, additional uses were approved in the United States for Atrazine 80W fall application for quackgrass control in com (1961) macadamia nut, chemical fallow following wheat or ecofallow and perennial ryegrass (1962) southern turfgrass species for sod production (1963) pineapple (1964) sorghum and conifer (1965) and rangeland (1975). 

Atrazine is the key herbicide facilitating ecofallow corn and sorghum production in the semi-arid Great Plains, where crop production is often uncertain and profits to farmers are often marginal. The success of atrazine in ecofallow is attributable to its duration of weed control as a soil-applied herbicide, the broad spectrum of weeds controlled, the low cost per area treated, and its safety to crops. In this semi-arid environment, maintaining weed-free fallow with repeated applications of nonresidual herbicides is not an economically viable alternative to atrazine. 

Reducing tillage can have beneficial effects on soil structure and seedbed quality. Phillips (1964) observed that sorghum seedling emergence was better in chemical fallow treatments than in V-bladed treatments. Planter depth control and seed placement into proper soil moisture are achieved more readily in hrm, untilled soils than on fluffy, tilled seedbeds. Furthermore, planter colters cut through plant residues more readily on firm soils. 

Atrazine remains the standard herbicide for making the transition from wheat to sorghum or corn in Great Plains cropping systems. Even where more intensified crop rotations have been developed, they are built around winter wheat followed by ecofallow sorghum or com. The success of atrazine is due to its persistence as a soil-applied herbicide, to the broad spectrum of weeds controlled, to its low cost per acre, and to its safety on sorghum and com. In the Great Plains, repeated burndown of weeds in fallow with nonresidual herbicides is not a viable alternative to the role that atrazine plays. 

Baker, L.O., J.L. Krall, T.S. Aasheim, and G.P. Hartman (1956). Chemical summer fallow in Montana. Down to Earth, 11 21-23. Burton, R.L, J.D. Burd, O.R. Jones, and G.A. Wicks (1990). Crop production strategies for managing greenbug (Homoptera Aphididae) in sorghum. J. Econ. Entomol., 83 2476-2479. 

Triazine herbicides are particularly well suited for conservation tillage because they provide foliar and residual control of a broad spectrum of weeds. Atrazine, simazine, and metribuzin are used in com, atrazine and propazine in sorghum, metribuzin in soybean, and simazine reduces tillage required for weed control in many perennial and tree crops. Atrazine is also used extensively in chemical fallow cropping systems in rotations involving corn, sorghum, and wheat. Cyanazine was also used extensively in corn and cotton until 2002. 

Uses Preemergence and postemergence herbicide for control of some annual grasses and broad-leaved weeds in com, fallow land, rangeland, sorghum, non-cropland, certain tropical plantations, evergreen nurseries, fmit crops and lawns. 

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