Maize: tortillas to cornflakes

Maize, or corn, provides staple food for much of the world’s population in developing countries where it is used to make porridge, bread and tortillas, and also the fast-foods of western society - breakfast cereals, sweet corn and popcorn. All around the world, maize grain is a basic livestock feed, and the crop can be cut while still green to make silage as a winter feed. Also, over recent years maize has been increasingly used as a feedstock for the production of bioethanolDescription Bioethanol is ethanol of biological origin. Crops containing sugar or starch grown for energy use include sugar beet, sugar cane, maize and wheat. "2nd generation" bioethanol will be made from cellulose from, e.g. waste straw and stover, willow and popular trees, sawdust, reed canary grass, switchgrass, Miscanthus. Authoritative On-line References and Resources http://www.eere.energy.gov/afdc/fuels/ethanol.html The US Department of Energy's Office of Energy Efficiency and Renewable Energy has am Alternative Fuels and Advanced Vehicles Data Center containing key information on all biofuels..

Paraquat is a versatile and important herbicide for weed control in maize. It can be applied from before a crop is planted right up to harvest. Paraquat can be used for burndown prior to planting in conservation tillageDescription Any tillage and planting system that covers 30 percent or more of the soil surface with crop residue after planting to reduce soil erosion by water. Authoritative On-line References and Resources Purdue University-based Conservation Technology Information Centre. systems like no-tillDescription Also known as conservation tillage or zero tillage is a way of growing crops from year to year without disturbing the soil through tillage ie cultivating the soil usually with tractor-drawn implements. Authoritative On-line References and Resources No-till.com:  A portal for on-line information about no-till farming.. As an alternative to plowing the land, this helps to prevent soil erosionDescription Displacement of solids (soil, mud, rock and other particles) usually by the agents of currents such as, wind, water, or ice by downward or down-slope movement. Authoritative On-line References and Resources http://soilerosion.net/ This site brings together reliable information on soil erosion from a wide range of disciplines and sources. It aims to be the definitive internet source for those wishing to find out more about soil loss and soil conservation.. In the US Corn Belt, although some of the most highly erodable land has been taken out of production, and erosion has decreased since the ‘dust bowl’ days of the 1930s, the average annual loss of soil by erosion has been estimated to be still as high as 14 t/ha.

Since the introduction of GM crops, intensive use of glyphosate has caused new weed problems as species less well controlled have ‘shifted’ to become more dominant and some species have evolved biotypes which are resistant to glyphosate. Using paraquat as an alternative non-selectiveDescription A chemical product used for eliminating all types of weeds (annual and perennial grasses and broadleaved weeds). Authoritative On-line References and Resources http://www.weeds.iastate.edu/ An invaluable source of contemporary information about herbicides and weeds from Iowa State University. herbicide with a different mode of action is important to avoid problems of weed shiftsDescription A change in the weed community within a field i.e. relative abundance or type of weeds. This can be the result of a management practice like herbicide use or any other phenomenon that brings about a change in weed species composition. Species or biotypes adapted to current weed management practices increase, whereas weeds susceptible to those practices decrease. Authoritative On-line References and Resources http://www.weeds.iastate.edu/mgmt/qtr00-1/popdyn.htm A classic article on weed population dynamics on the Iowa State University Weed Science website. and resistanceDescription The inherited ability of a plant/weed to survive a dose of a herbicide normally lethal to that species. Authoritative On-line References and Resources http://www.weedscience.org/in.asp The International Survey of Herbicide Resistant Weeds monitors the evolution of resistant species and assesses their impact. All confirmed instances of new cases are listed., and to keeping the option to use glyphosate.

Unlike glyphosate, paraquat is not systemic and has only contact action. If small amounts land on crop leaves there is little or no damage. So, paraquat can be used for inter-row weed control to remove weeds growing between the crop rows.

Paraquat does not leachDescription The natural process by which water soluble substances are carried downward through the soil into groundwater. or run-offDescription The occurrence of surplus liquid (like rain) which originates up-slope and is collected beyond the ability of the soil to absorb it. The surplus liquid then flows away over the surface to reach the nearest surface water (pond, lake, river). Authoritative On-line References and Resources US Geological Survey's Water Science School to pollute soil or surface waters because it is immobilised and deactivated immediately on contact with soil.