Farmers using this method leave crop residues in the field between seasons. The intact roots hold the soil in place, reducing both wind and water erosion, and the undisturbed soil is able to regenerate natural soil horizons. No-till agriculture also reduces emissions of CO2 because the intact soil undergoes less oxidation. In many cases, however, in order for no-till agriculture to be successful, farmers must apply herbicides to the fields before, and sometimes after, planting so that weeds do not compete with the crops. Therefore, the downside of no-till methods is an increase in the use of herbicides.
Conventional agriculture relies on plowing and tilling, but plowing and tilling have negative effects on soils. Every time soil is plowed or tilled, soil particles are disturbed and broken apart and become more susceptible to erosion. In addition, repeated plowing increases the exposure of organic matter deep in the soil to oxygen. This exposure leads to oxidation of organic matter, a reduction in the organic matter content of the soil, and an increase in atmospheric CO2 concentrations. Tilling, in addition to irrigation and overproduction, has led to severe soil degradation in many parts of the world.
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