What is the importance of conservation tillage in organic farming and effects of tillage on the soil and environment?
Conservation tillage does not loosen or invert the soil; it leaves vegetation in place to help prevent wind-erosion losses. Crop residues on the soil surface reduce wind velocity and the ability of wind to move soil particles. Conservation tillage in organic farming combines the principles of organic farming with the benefits of soil erosion control achieved by the conversion from ploughing to either reduced tillage or no-tillage/direct-seeding. Since tillage fractures the soil, it disrupts soil structure, accelerating surface runoff and soil erosion. Tillage also reduces crop residue, which help cushion the force of pounding raindrops. Without crop residue, soil particles become more easily dislodged, being moved or 'splashed' away. It has been well documented that increased tillage intensities can reduce soil organic matter in the topsoil due to increased microbial activity and carbon (C ) oxidation. The potential loss of soil organic matter due to tillage operations is much higher for high organic matter soils than low organic matter soils.
Tillage intensity and cover crops influence the amount of soil mixing, site erodibility, nutrient loss, and soil structure, moisture, and temperature. Anything that changes infiltration, leaching, or runoff, or affects crop root development, could change site productivity and thus nutrient needs. Tillage effects on soil organic matter can be magnified through soil erosion and loss of soil productivity. Soil organic matter is a natural reservoir for nutrients, buffers against soil erosion, and improves the soil environment to sustain soil productivity. Tillage is an important agricultural practice to manage crop residues, control weeds, and prepare the soil for planting, among others. However, the use of tillage can stimulate loss of soil organic carbon (C) to the atmosphere as carbon dioxide (CO2). Conservation tillage improves soil aggregate stability that enhances nutrient retention and reduces soil erosion thereby contributing to soil fertility and mediates air permeability, water infiltration, and nutrient cycling. Tillage turning the soil to control for weeds and pests and to prepare for seeding has long been part of crop farming. However, intensive soil tillage can increase the likelihood of soil erosion, nutrient runoff into nearby waterways, and the release of greenhouse gases into the atmosphere. Since tillage fractures the soil, it disrupts soil structure, accelerating surface runoff and soil erosion. Tillage also reduces crop residue, which help cushion the force of pounding raindrops. Without crop residue, soil particles become more easily dislodged, being moved or 'splashed' away. Penetration resistance and bulk density of a sandy clay loam were increased by minimum tillage in the top 200 mm of the soil when compared with those in chisel plough and conventional tillage systems, while soil water content at planting was less affected.
Tillage effects on soil organic matter can be magnified through soil erosion and loss of soil productivity. Soil organic matter is a natural reservoir for nutrients, buffers against soil erosion, and improves the soil environment to sustain soil productivity. Tillage is an important agricultural practice to manage crop residues, control weeds, and prepare the soil for planting, among others. However, the use of tillage can stimulate loss of soil organic carbon (C) to the atmosphere as carbon dioxide (CO2). Conservation tillage reduces soil erosion, conserves soil moisture, conserves energy, increases soil organic matter content, and consequently, soil quality. However, conservation tillage may compact surface soil horizons and may lead to poor root growth. Conservation tillage in organic farming combines the principles of organic farming with the benefits of soil erosion control achieved by the conversion from ploughing to either reduced tillage or no-tillage/direct-seeding. Since tillage fractures the soil, it disrupts soil structure, accelerating surface runoff and soil erosion. Tillage also reduces crop residue, which help cushion the force of pounding raindrops. Without crop residue, soil particles become more easily dislodged, being moved or 'splashed' away. Conservation tillage technology can reduce the soil bulk density and promote the redistribution of soil pore space in different soil layers, forming a better soil structure, thereby improving soil physical properties and soil aeration, improving rainfall infiltration and soil water storage capacity.