Improved water infiltration, less runoff and reduced evaporative losses in no-till systems can save from 5 to 12 inches per year, making more water available for crop production. The tilled grain sorghum on the right yielded only 61 bu/A in a dry year while the no-till on the left yielded about 121 bu/A.
The tilled plots in the foreground of this photo had considerable soil loss and runoff during intense spring rains. The tilled soil surface was susceptible to raindrop impact, causing erosion and surface crusting. The crop residue on the no-till plots in the background absorbed raindrop impact and allowed more water to infiltrate into the soil. With the improved soil structure, the crop is healthier in the no-till.
While tillage has been used to prepare a seedbed, it also destroys the existing root structures in the soil and some of the soil's biological life. Without this biological life, soil structure suffers and many of the nutrients are not as available for crop uptake.
Soil is much more than the individual particles of sand, silt, and clay. Ideally, the soil should be one-half solid materials (sand, silt, clay, nutrients, minerals, organic materials, and biological life) and one-half pore space (half of that containing water and the other half being air space). Biological life and organic matter provide the "glues" to create soil aggregates, forming soil structure.
Tillage of the soil has been used to prepare a seedbed, kill weeds, incorporate nutrients, and manage crop residues. The goal of the tillage system has been to provide a proper environment for seed germination and root growth for crop production.
The US Environmental Protection Agency is conducting an intermediate reassessment of atrazine label certification to ensure the safety of atrazine found in streams for aquatic life and human health. As part of this effort Syngenta was required to set up 40 monitoring stations in potential runoff sites across the Midwest.
Runoff and/or leaching can occur when pesticides are carried off the application site into water such as rivers, lakes and streams, wells, storm sewers, or into groundwater. Runoff/leaching can occur when too much pesticide is applied or is spilled on the surface, too much rainwater or irrigation water occurs in a short period of time, or highly water soluble pesticides are used.
To gain a better understanding of how, where and why water runs off and how to prevent pollution read the following UNL publications: