Organic Farming is a system of farming practices which is different from conventional farming that is heavily dependent on the use of synthetic fertilisers and pesticides. Organic farming is currently termed as ecological farming based solely on organic inputs. Ecological or organic farming systems have the potentials to reduce some of the negative impacts of conventional agriculture on the environment. The reduction or non-use of synthetic chemicals with organic farming system can decrease the environmental hazards and possible adverse effects on wildlife. Organic materials improve the physical, chemical and biological properties of soil in contrast to synthetic fertilisers. Use of organic materials is, therefore, necessary to sustain the productivity of soils as well as soil health. The most common organic materials which are currently used throughout the world are biofertilisers, humate fertilisers, manure spreaders, crop residues, green manure, guano, bone meals, compost, farmyard manure, fish meal, fish wastes, liquid manure, sewage sludge, slurry, etc.
Before the advent of chemical fertilisers the agriculture of Bangladesh was solely dependent on the use of organic materials. Three major sources of organic materials were animal manure, crop residues and domestic wastes. But agricultural practices without chemical fertilisers seem to be impractical because the country demands more production to keep pace with increasing population rather than quality products.
In Bangladesh, approximately 13% of the total cropped area is triple cropped, 50% double cropped and the remaining 37% areas are single cropped, settlement and water bodies. These soils are mainly used for Boro, Aman and Rabi crops. Some of the farmers are using chemical fertilisers, some are using chemical and organic fertilisers and some of the farmers are using only organic manure. Manure includes oil cake, household wastes, farm manure, farmyard manure and water hyacinth. Thus overall farming system of Bangladesh is very complex.
Continuous application of synthetic fertiliser and other chemicals has already created adverse effects on soil properties and as a consequence yield stagnation or even yield decline have resulted. To restore natural productivity of the soils use of organic materials is a must. Moreover, organic farming can also be extended for the production of vegetables and horticultural crops. [Sirajul Hoque]