Thursday, 7 November 2013

Let the sunshine in - growing crops and teak trees in Lao PDR

ACIAR research is shining light, literally, on how to successfully grow crops and teak together in Lao PDR...

Many smallholder farmers in the Luang Prabang region of northern Lao PDR are growing teak. At least 25,000 hectares of teak has been planted over the last 20 years. Current government policies support the continued expansion of new teak plantings. In most cases, farmers plant 1800-2500 trees per hectare and farm the land between the trees for 3 or 4 years. By that time the tree canopies block out sunlight and inhibit growth of plants underneath. This can make life difficult for farmers who don’t have enough land to grow crops somewhere else while their teak trees mature to a size of high value.

Another problem for farmers is that in the absence of good markets for small teak logs, they are reluctant to thin out densely-planted teak forests, even though this maximises growth and improves the quality of the remaining trees. So, how can research help farmers overcome these issues?

Intercropping in the Nelder Wheel teak trial
ACIAR’s teak research in Lao PDR, led by the University of Queensland, has studied the growth of teak at different initial stockings (concentrations of trees planted) through the use of ‘Nelder Wheel’ trials. In these trials, teak is planted in rows along the “spokes” of a wheel shape in the field. Because the distance between rows increases as you move out from the centre of the trial, you end up with different planting densities at each point along the spoke. By monitoring these trials over 5-10 years, you can determine the average growth of the teak at different stockings (from 100 to 2500 trees per hectare).

Five years down the track, this research is showing that the best rate to plant to maximise tree width and height is 600 trees per hectare. This is a fraction (a third or less) of the number of trees traditionally grown per hectare. Importantly, this approach gives farmers the option of growing crops in the extra space between trees.

Last year, we tested the growth of crops including maize, pigeon pea, soybean and cassava under different teak spacings. The crops were planted in the spokes of a Nelder Wheel trial and early results indicate that they can all be grown very successfully when the 5-year-old teak stocking is 600 or less per hectare.

So, this system would have a triple benefit to farmers: the trees grow faster to high-value size, crops can continue to be planted between maturing trees, and non-commercial tree thinning is no longer needed. 
Mr Khamsone with his teak agroforestry system, with banana and
broom grass growing in the sunny spaces between tree rows
But can these improvements be adopted by Lao farmers?  It looks like the answer is ‘yes’.  At the small village of Ban Phonsavanh, I met local farmer Mr Khamsone Phonsavanh who has worked with project staff to develop an agroforestry system that works for him. His system involves paired rows of teak, with banana, broom bush and some upland rice planted in the spacing between the paired rows. He told me he was happy with the teak trees which are now 4 years old, and knows that they will provide him with a good return in the future, and in the meantime he can still earn some income from his other crops.

By Tony Bartlett, ACIAR's Forestry research program manager

More information:
ACIAR project FST/2004/057 Enhancing on-farm incomes through improved silvicultural management of teak and paper mulberry plantations in Luang Prabang Province of Lao PDR 
Led by University of Queensland, Australia. Other partners include:
Salwood Asia Pacific Pty Ltd, Australia
Luang Prabang Agriculture and Forestry College, Laos
National Agriculture and Forestry Research Institute, Laos
Souphanavong University, Laos

ACIAR's forestry research in Lao PDR (2011 bulletin)

Lao PDR research strategy

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