Hung Yen’s terrain is relatively flat, with no hills and mountains. It slopes down in North-southern and West-eastern direction and alternated by frequently flooded hollows. The high terrain is mainly in the Northwest, including Van Giang, Khoai Chau and Van Lam districts; the low terrain in Phu Cu, Tien Lu and An Thi districts. The topography of Hung Yen province can be divided into 5 sub-regions as follows:
- The subzone outside the Red River and Luoc River dykes is added new alluvium every year, so the outside of the dyke is usually higher than the inside of the dyke and gradually lowers from north to south according to the flow. The soil core is from +7m to +9m high in Xuan Quan commune, Phung Cong commune (Van Giang district) and gradually lowers to +3m to +4m high in Thuy Loi commune (Tien Lu district), Tong Tran commune, Nguyen Hoa commune (Phu Cu district).
- The sub-zones of Khoai Chau, Van Giang, My Hao, Yen My and Van Lam have soil cores of +6m to +7m high.
- The sub-zones of Hung Yen city, Phu Cu district, Tien Lu district adjacent to the Red River and Luoc River have an alluvial soil layer about 1m to 1.5m thick, the soil core is +3m to +3.5m high.
- Bac Van Lam sub-zone has soil core from +4m to +5m high.
- The sub-zones of An Thi, Northern Phu Cu, Western Kim Dong have soil cores of +2m high.
Hung Yen's topography clearly affects farming. In the past, there were frequent droughts and floods. The highlands cannot hold water, while the lowlands cannot drain water in time during the rainy season. For each region, there is also a local differentiation in topography; upland areas have low places like in Dai Hung (Khoai Chau) and low areas have high places like in Nhat Quang (Phu Cu).
Geological characteristics.
Hung Yen Province is located in a sunken area in the Red River Delta and formed by the sediments of the Quaternary period, with the depth of 150m - 160m. In order of stratigraphy, the soil and rock types are as follows:
- Pleistocene sediments, 130 to 140 m thick with coarse crumb sediments include grit, gravel, coarse sand, medium sand .
- Holocene sediments, with a thickness of 5 to 30m, are mainly composed of sandy clay, powdery clay, and organic clay, distributed on the stratigraphic surface.
Soil characteristics.
The land has been formed by the accretion of the Red River’s silt. The mechanized composition of the soil, from natural to mixed soil, which gets aluminous, can be divided into three types:
* Alluvial soil in the Red River is deposited: Dark brown color, neutral soil, little acidity, this is a good soil.
* Alluvial soil in the Red River is not deposited: This type has a thick alluvial layer, the mechanical composition ranges from medium to heavy soil, neutral soil with little acidity.
* Alluvial soil in the Red River has a patchy layer, with no sedimentation: Light brown soil, thin alluvial layer, medium to heavy mechanical composition, strongly clayey, slowly decomposing organic matter, often sour.