Land evaluation of rainfed lowland rice areas in the Mekong delta of Vietnam

Duong Van Ni

Date

1993

Abstract

Physical land evaluation was conducted on the Rainfed Lowland Rice areas (RLRs) in the Mekong Delta of Vietnam, using the FAO (1976) framework. The RLRs were divided into physical zones (PZs), whether the soil is acid sulphate or non-acid sulphate and whether flood water is greater or less than 30 cm. The PZs were subdivided into land units (LUs) called Rainfed Lowland Rice Groups (RLRGs) based on rainfall, soil, salt water intrusion, flood water depth, inundation periods, fresh water availability and tidal action. The present land use systems (LUSs) in the whole study area were identified and described. The land use requirements (LRs) of each LUS were determined through surveys, field experiments and interviews with the farmers. The land characteristics (LCs) of each RLRG were determined by soil survey, laboratory analysis and other field surveys. Land suitability evaluation was performed by matching LC with the LR of each LUS, from which a suitability classification for the study area was generated. Four (4) main PZs were identified. The dominant zones are the non-acid sulphate soil with flow water of less than 30 cm located at the coastal side and the acid sulfate soil with more than 30 cm flood water located inland. There are seven (7) important RLRGs in the study area, reflecting the kind of hydrology and soil constraints. The cropping systems and management practices were different among RLRGs. Nineteen (19) major LUSs were found in the area. The LUSs are basically all cropping systems, two (2) are triple rice cropping systems (CS), three (3) are double rice CS, four (4) are single rice CS, and the rest are CS with crops other than rice. The most promising LUS in each RLRG, based on area, profitability and environmental soundness, were identified. The physical and socio-economic requirements of these LUSs were also identified and described for farmer's adaptation purposes. Results of land evaluation indicate the suitability classification of the different LUSs for each RLRG. Farmers can use these results as basis for selecting alternative land use systems.

Document Type

Master Thesis

Degree

Master of Science in Soil Science

Language

English

LC Subject

LG 995 1993 S72 D86

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Rainfed lowland rice -- Vietnam, Rice -- Vietnam

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