Organic farming is a type of farming in which organic methods are used for farming.this includes the use of manure and compost which does not harm the soil.
Farming in which only natural methods of manuring and pest control are used and the plants and animals raised are not genetically modified to improve yields is called organic farming.
Subsistence agriculture is practised by poor farmers whose plots are so small that they can produce just enough to support their families.Subsistence farming includes some systems of  farming such as Shifting agriculture and nomadic herding.
In Commercial agriculture, crops are grown mainly for sale.Generally, farmers specialise in growing a type of crop, and farming is highly organised. Some important types of commercial agriculture are commercial grain farming, plantation agriculture, diary farming and ranching.