Cultivating without ploughing by leaving the residue from the previous year's crops in place to hold soil and moisture, then scratching or chiselling-in seeds, which sprout through the decomposing residue. Crop rotation is used to break down insect cycles. Weeds are controlled by new systemic herbicides that quickly break down.
It 1993, it was predicted that new legislation requiring conservation in the USA is likely to push up the proportion of cropland under some kind of residue management from its current figure of 25% to around 50% within two years. By the end of the century it was likely to be around 80%. It was also reported that farmers engaged in this agricultural revolution were finding increases in yields and a reduction in the cost of producing crops of 25-30%.