Wheat fallow

W. J. Parton and P. E. Rasmussen, Long-term effects of residue management in wheat/fallow century model simulations. Soil Sci. Soc. Am. J. 5H.550 (1994). 

Follett RF, Paul EA, Leavitt SW, Halvorson AD, Lyon D, Peterson GA (1997) Carbon isotope ratios of Great Plains soils and in wheat-fallow cropping systems. Soil Sci Soc Am J 61 1068-1077... 

Fenster, C.R., O.C. Burnside, and G.A. Wicks (1965). Chemical fallow studies in winter wheat fallow rotations in western Nebraska. Agron. J., 57 469 470. 

Uses herbicide to control annual grasses and broadleaf weeds in cereals, cotton, maize, onions, peanuts, peas, potatoes, soybeans, sugar cane, and wheat fallow. 

In regions where rainfall is lower and/or less reliable, such as in Western Australia, simpler rotations with longer pasture or fallow phases are more likely. If the soil is heavier, with better nutrient and water retention, a suitable organic crop rotation would be pasture (vetch or medic Medicago spp. hay) > pasture > wheat > chickpeas > fallow > wheat. However, on lighter sandier soils, the rotation would consist of pasture > pasture (green manure) > wheat > oats or simply pasture > pasture > wheat (McCoy and Parlevliet 2001). 

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). 

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. 

Aasheim (1948) at Havre, Montana, was among the first to reduce tillage trips in a wheat stubble fallow by using chemicals to control weeds. He used 2,4-D and dinoseb, applied in water or diesel fuel, calling this practice chemical fallow. Later, dalapon replaced dinoseb to obtain better grass control (Baker et al., 1956). 

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. 

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. 

Producers thought they had found a total solution, but it became apparent that they had then created another problem. For example, wheat plant residues contain foliar pathogens such as Septoria tritici (8). The following season, spores are produced by these fungi and are blown to adjacent fields of wheat where severe infection may result. Mechanical tillage destroys the crop residue chemical fallow does not. So in solving one problem, another was... 

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