Kindly see here too..

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1981-81222013000300013

This too may be explored,,,

https://peopleandtheenvironment.wordpress.com/2011/09/24/shifting-cultivation-and-biodiversity-conservation-in-bhutan/

In shifting cultivation method of agriculture an area of land is cleared off its vegetation and cultivated for a period of time and then abandoned. Thus that abandoned land then gets ample opportunity to restore its fertility naturally. It is thus allowed to be reverted to its normal and natural vegetation gets regenerated. It has both advantages and disadvantages. We must have assess the trade offs.

Advantages

1. It helps used land to get back all lost nutrients and as long as no damage occurs therefore, this form of agriculture is one of the most sustainable methods

2. The land can be easily recycled or regenerated thus; it receives seeds and nutrients from the nearing vegetation or environment

3. Shift farming saves a wide range of resources and provides nutrients because a small area is usually cleared and the burned vegetation offers many nutrients

4. It helps to ensure more productivity and sustainability of agriculture

5. In shift farming, it is easy to grow crops after the process of slash and burn. That's why shifting agriculture is also popularly known as slash-and-burn farming.

6. It is an environmentally friendly mode of farming as it is organic

7. Shift cultivation is a mode or form of weed control

8. It also plays a crucial role in pest control

9. Soil bone diseases is also reduced significantly through shifting mode of farming

10. It also reduces the rate of environmental degradation

Disadvantages 

1. It can easily lead to deforestation because when soil fertility is exhausted, farmers move on and clear another small area of the forest

2. Shift farming can easily cause soil erosion and desertification

3. It destroys water sheds

4. Shift farming is uneconomical

5. It easily leads to loss of biodiversity

6. Water pollution in coastal areas easily occur because of raw sewage and oil residue

7. Shifting mode of farming restricts the intensity of land use

Therefore, shifting cultivation has been under a lot of attack based on the principle that it degrades soil fertility and general fertility of forestlands in tropical areas. Nonetheless, this mode of farming is highly an adaptation to tropical soil conditions in areas where continued and long term cultivation has been practiced on the same soil without advanced soil conservation methods and use of fertilizers. This is because it would be highly detrimental to the fertility of the land.

In such areas, it can be highly preferable to cultivate land for a shorter period of time and abandon it before the soil fully exhausts its nutrients. The most attractive feature is that these disadvantages can be managed through

1. Quality education to help the farmers understand the consequences of shift cultivation

2. Agro forestry which involves growing crops and trees at the same time thus enabling farmers to shelter canopy of trees hence, preventing soil erosion. crops also benefit from dead organic matter

3. Selective logging can also be practiced

4. Forest reserves by protecting certain areas from cultivation

5. Afforestation where cut trees are replaced to maintain the health of canopy

6. Close monitoring by use of advanced technology as well as photography to check any activities that take place hence, ensuring sustainability.