Yes, FAO approach

Dear Phan Hoag Vu,

you find the originals under

https://www.mpl.ird.fr/crea/taller-colombia/FAO/AGLL/pdfdocs/aeze.pdf 

http://www.fao.org/docrep/w2962e/w2962e00.htm#P-2

Regards, Kees

Dear Stigter and Aguilar-Rivera,

I really thank you so much. Those are good guidelines which help my research.

Regards, PHVu

Certain specific crops due to rainfall, temperature, humidity, soil type etc which are conducive for one contiguous homogeneous area form a zone.   

Yes you can do by different approaches in addition to FAO approach. The other approaches may be following the natures situations including land cover, slope, altitude, rainfall, soil type, relative humidity, aligning with different government policies, etc. Based on these approaches, you can divide the agro-ecological zones. 

Regards,

Dear all,

that approach described by Beemnet may be able to derive environmental ecological zones but it is different from the FAO approach were agricultural land use is what the zoning aims to define.

FAO writes:

" Policy-makers and land users face two basic challenges: the need to reverse trends of land degradation in already-cultivated areas by improving conditions and re-establishing their level of fertility; and prevention of the degradation of land resources in new development areas through appropriate and just allocation and use of these resources to maintain productivity and minimize soil erosion. In both cases an integrated approach to planning and management of land resources is a key factor in a solution which will ensure that land is allocated to uses providing the greatest sustainable benefits. FAO has been promoting the integrated planning and management of land resources in cooperation with regional institutions, individual countries as well as land users."

Agro-ecological zoning in that context is different and more cumbersome and elaborate than what you describe because it will be a lot more difficult to derive the potential agricultural use from the data that is collected in your approach.

Best wishes, Kees

In India, National Bureau of Soil Survey and Land Use Planning (NBSS&LUP),Nagpur has delineated twenty agro-ecological regions and sixty agroecological subregions based on physiography,soils,climate,length of growing  period and available soil moisture and mapped them on 1:4.4 million scale.The website of the institute may consulted for more details.

Dear all,

Thank for your all answers. I have difficulty for choosing the appropriate factors to agro-ecological zone for different ratios. For example scales: 1:1.000.000, 1:250.000, 1:10.000, etc...

I really hope receive more comments from you.

Regards, P.H.Vu

Dear Hoang Vu;

Agro-ecalogical zoning (AEZ), defines zones on the basis of combinations of soil, landform and climatic characteristics. For example our region, Southeastern Anatolia Region, is relatively a small region of Turkey in terms of land size, However, the region has been divided three seperated agro-ecological zone due to the the distinctive characteristics.

Regards…

Dear Hoang Vu,

I think the following text and the link can help you a lot to understand the factors of agro-ecological zone.

"Agroecological Zone land areas recognized on the basis of hydrology, physiography, soil types, tidal activity, cropping patterns, and seasons. In fact an agroecological zone indicates an area characterized by homogeneous agricultural and ecological characteristics. This homogeneity is more prominent in the sub region and unit levels. The agroecological zones of Bangladesh have been identified on the basis of four elements such as physiography, soils, land levels in relation to flooding and agroclimatology. Bangladesh has been tentatively divided into 30 agroecological zones. These 30 zones have been subdivided into 88 agroecological sub-regions, which have been further subdivided into 535 agroecological units."

For detail see the following link

http://en.banglapedia.org/index.php?title=Agroecological_Zone

Best regards,

Byomkesh Talukder

The diferences among soil, landform and climatic characteristics of a region zones comprise agro-ecalogical zones (AEZ). In my opinion, absent a accurate method, identfing the border of AEZ each other. Nevertheless, the differences between harvesting time of the same crop, grown in many part of a region, can be accepted as a good indicator of the differences between the zones.

Dear Mehmet,

I feel that it does not apply to the same crop, because there may be different varieties in use, less well or better adapted to a zone. But it does also not apply to one variety because sowing times may well have been different.

You may argue then that the length of the growing period of one and the same variety could be used to distinguish between zones. This comes closer but is still limited and flawed because an ecological zone has climatological, soil and other environmental parameters with different influence on that single variety. Its growing period depends differently on these different parameters in the zone.

Potential agricultural/land use of a zone appears a more suitable integrating factor of what such different parameters allow.

Best wishes, Kees

Very interesting discussion by all colleagues.I compliment Dr. Talukder for information on agroecological regions,subregions and even units in Bangladesh.The agroecological units may be the management zones(535) for agriculture.They have also taken into consideration the land level in relation to flooding as one criterion.If we choose more parameters we may have to go for modelling.Also, the dominant parameters should be relevant to the country or region.In each region the dominant soil,the climate  type and cropping system should be included/covered.At subregion and unit level one can go for other features/limitations for better management of natural resources.