Tillage refers to the mechanical operation of soil to improve plant growth conditions before planting or during crop growth. There are three basic purposes of farming, 1) improving soil structure; 2) burying crop residues and organic fertilizers and Blend into the soil: 3) Remove weeds or other unwanted plants. According to the above definition, which of the following is the following? ['Dig a Ditch in the Orchard.', 'Spraying herbicides to remove weeds.', 'Smash the topsoil that has compacted after the rain.', 'Planting green manure crops in farmland in winter.']