Friday, 10 June 2016

Land use evaluation in the Central Dry Zone of Myanmar

The Central Dry Zone (CDZ) of Myanmar is an area characterised by a short monsoon rainfall season followed by eight months of dry and low productivity soils, mostly hilly to gently undulating terrain with sandy soils and only a few areas of more productive clays in the valleys. The soils lack organic matter, are infertile and are generally acidic. This combined with low rainfall means that farming in the area is relatively unproductive and risky.

ACIAR has just started a new project on land use evaluation in the CDZ. It will start with a pilot area called Pyawbwe township, about a two hour drive north of Nay Pi Taw, the capital of Myanmar. The aim of the project is to better understand the variation and hence the constraints and opportunities of different soils and map these in detail. Then the project will develop land use planning guidelines with land management authorities and farmers and share those with government agencies and NGOs operating in the region.

Project team discussing soils with farmers. Photo: Dr Evan Christen, ACIAR

Discussions with farmers revealed that they were aware of the different types of soils and their varied fertility. Farmers preferred to put fertiliser on their poor soils to boost yield rather than on their good soils. The project will have to investigate whether this intuitive approach really is the best use of limited resources.

Farmer watering coriander. Photo: Dr Evan Christen, ACIAR
Irrigation with shallow groundwater has become increasingly common due to the low rainfall in recent years and farmers’ need to boost income. However, the groundwater is often saline and sodic leading to soil problems such as slaking and hard setting affecting the germination and growth of some crops like coriander.

Many of the soils are very sandy and have very low organic matter. This means their capacity to hold water and nutrients is low, any fertiliser will be easily leached out. Also the soils are vulnerable to water infiltration problems due to surface compaction and on sloping land vulnerable to erosion. These problems have been exacerbated over time by tillage practices that destroy soil structure and organic matter.

Sandy soil being disc ploughed. Photo: Dr Evan Christen, ACIAR

In the CDZ very little fertiliser is used, often only farm yard manure is used and at low rates. The soil erosion is taking away topsoil and nutrients. The erosion is within the fields and also leading to gullies in the landscape.

The project will use modern terrain analysis techniques together with stratified random sampling to characterise the soils in the CDZ. Discussions with farmers in the field can be used to assess the constraints of various soils, how they can be practically (affordably) addressed.

In-field discussions between researchers, extension staff and farmers. Photo: Dr Evan Christen, ACIAR
Also, discussions with research and extension staff will develop guidelines for best management of the soils with respect to fertilisers, tillage and organic matter to be provided to farmers. The plan is that the exercise of land use planning will be community based and so this project will pilot participatory land use planning in the township.

By Dr Evan Christen, Research Program Manager for Land and Water Resources, ACIAR

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