In CA less than 15 % of the soil surface is moved and all crop residue and other trash is left in the field. Through this method, land can be prepared prior to commencement of the rains, thus enabling timely planting. Old crop residue and other trash that is left in the field restricts both water and wind erosion whilst also shading the soil. This vegetation residue rots down, improving the humus (or soil organic carbon, SOC) content of the soil, and ultimately soil health.