Ca Mau is a new land deposited by alluvium, formed by two currents in the East Sea and the Gulf of Thailand, receiving alluvium from the Mekong River. In general, the province’s land is young, newly exploited and used, with average fertility, high organic matter content but due to alum and saline intrusion, it is suitable for aquaculture and planting mangrove and brackish forests.

The group of fewer saline lands is considered the best land for agricultural production.
 

In terms of land classification, Ca Mau province is divided into 6 groups, with 26 units of map guidance according to the FAO/WRB classification system.

The survey results show that 91.41% of the natural area of the province is an alum and saline soil; in which, the group of alum land occupies the largest area of 268,843 ha (50.77% of the natural area), followed by the group of salty land: 215,135 ha (accounting for 40.63% of the natural area). Group of peat soil under the melaleuca forest cover is distributed in U Minh lowland area, alluvial ground, sandy land along the coast, and red-yellow land distributed outside the island clusters only occupy a small area (about 4.3% of the natural area), 4.29% of the remaining area is river and canal. The main groups of land are distributed as follows:

Sandy soil group: The area of sandy land is 424 ha, accounting for 0.08% of the natural area, distributed in a narrow stretch, parallel to the coast in Khai Long area, Dat Mui commune, Ngoc Hien district. In general, sandy lands have a light mechanical composition and average fertility. This sandy land also has suspended pulses, and sweeteners, so some places have exploited it to grow crops (melon, squash, vegetables, beans, etc.). All crops have good livelihoods and good yields on this type of land. 

Saline soil group: 215,135.55 ha, accounting for 40.63% of the natural area, formed on young Holocene sediments, originating from rivers, seas, or mixed rivers and seas. Soils often have heavy mechanical composition and salic properties. This land group is most distributed in Dam Doi district (26.7% of the total salty land area), followed by Tran Van Thoi district (20.53%), Cai Nuoc district (17.21%), Phu Tan district (12.17%) and U Minh district (11.33%). The remaining districts accounted for only about 12.06%. Currently, most of this land is being used for shrimp farming so it is almost salty all year round, the rest is mangroves located in the coastal protection forest belt. This is a non-alluvial land, distributed in a terrain quite suitable for shrimp farming. Therefore, in addition to the coastal protection forest belt, the interior should be arranged to specialize in shrimp farming or incorporate the shrimp-forest model on this land.

The most saline soil group is distributed in Dam Doi district.
 

In the saline soil group, the saline soil area is less than 70,851 ha, accounting for 13,38% of the natural area, distributed mainly in the form of high terrain running along the North - South road from Thoi Binh district to Ca Mau city, the form of high ridges in the shape of a bow in the central area of Tran Van Thoi district or the form of natural dikes along the Cai Tau and Trem rivers. Tran Van Thoi district has the least saline soil area (33,706 ha), followed by Ca Mau city (5,993 ha). Saline land is less rated as the best land for agricultural production compared to other lands in Ca Mau province. Many types of agricultural land use such as 2-crop rice, 1-crop rice, rice + field fish, flowers, and fruit trees, etc. are developed on this land. The main limitation for the arrangement of crops on this land is mainly due to the scarcity of freshwater resources in the dry season. Therefore, in order to increase the efficiency of land use, it is necessary to promote irrigation to overcome the shortage of fresh water, creating favorable conditions for the arrangement of increasing services and diversifying crops on this type of land. 

Acid sulfate soil group: Occupying the majority with an area of 268,843.44 ha, accounting for 51.05% of the natural area. This group of land is most distributed in Ngoc Hien district (21.59% of the total area of alum soil), followed by Thoi Binh district (19.63%). The remaining districts only account for about 4-8% of the total alum land area. The alum land in Ca Mau is divided into 02 sub-groups: Potential alum land and active alum land; in which, potential alum land is distributed most concentrated in Ngoc Hien district (58,041 ha), followed by Nam Can district (39,249 ha) and Dam Doi district (18,850 ha), Phu Tan district (16,636ha), Thoi Binh district (15,088ha), Tran Van Thoi district (13,437ha). The remaining districts are about 4,000 - 6,000 hectares in size. The most active acid sulfate soil is distributed in U Minh district (30,055 ha), followed by Tran Van Time district (7,868 ha), the remaining districts are very small in scale.

Alluvial land in Ngoc Hien district.

Peat soil group: Only one unit of land map guidance is peat and alum land (TS) with an area of 9,785 ha, accounting for 1.85% of the total natural area, distributed centrally in the capercaillie area in the south of U Minh district (6,661 ha) and the north of Tran Van Thoi district (3,124 ha).

Currently, most of the peatland area is cajuput forest, a few areas are crop fields. In the dry season, peat is easy to burn or decompose quite quickly in the absence of moisture. The capercaillie forest on peaty land is a peaty forest ecosystem specific to our country, so it is necessary to strictly protect this peaty land area.

The group of red-yellow land: Only one unit of map guidance is red-yellow land on acid magma (Fa) with an area of 638.52 ha (accounting for 0.12% of the natural area) distributed mainly in 3 near-shore island clusters such as Hon Khoai Island Cluster, Hon Chuoi Island Cluster, and Hon Da Bac Island Cluster. Currently, the majority of Fa land in Ca Mau is forestry land, unused land, residential land and specialized land. In the areas of forestry land and unused land, it is recommended to plant, renovate and protect forests to protect the land against erosion.

Riparian and coastal alluvial land group: This land group has only one mapping unit is the alluvial land with an area of 11,213 ha (accounting for 2.16% of the natural area), distributed in strips of land extending parallel to the edge of the West Sea and Ca Mau Cape (Nam Can district 3,338 ha, Ngoc Hien 8,629 ha).