Accompanying reading:

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1 The traditional trees in paddy fields

2 Accompanying reading: Vityakon, P The traditional treesin-paddy fields agroecosystem of Northeast Thailand: Its potential for agroforestry development. Regional Development Dialogue 14(1):

3 Trees in paddy fields constitute the biodiversity of the paddy field agroecosystem. Rice paddies are a complex agroecosystem and a multiresource base for farmers.

4 Topographic and Soils Characteristics of Northeast Thailand Phetchabun mountain Khon Kaen Chi river Mun river Panom Dong Ruk mountain

5 Tropaquepts Paleustults Paleustults Paleustults/Paleaquults Ustifluvents Paleaquults Paleaquults Paleaquults Paleustults River Levee Flood plain Low terrace Middle terrace Low terrace Middle terrace Middle terrace Low terrace Middle terrace High terrace Hill Flood plain Non-flood plain Mini-watershed Non-flood plain Schematic cross section of topography and soils in Northeast Thailand Source: Vityakon and Keerati-Kasikorn (1987)

6 Hamlet Transect of a mini-watershed Field shelter Upland Upper Paddy Lower Paddy Upper Paddy Upland f Soils Paleustult Paleaquult/ Paleustult Paleaquult Crops Cassava Rice, Rice followed by Cassava, vegetables rcane Problems Drought r melon Erosion Sugarcane Insufficient water Occasional flooding

7 Forest There are 4 types of forest in the Northeast: 1. Dry dipterocarp forest: The dominant forest type which cover 53 % of forested area in Dry evergreen forest: 36% 3. Mixed deciduous forest: 10% 4. Pine forest : 6%

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9 Crops - Rice: Rainfed wet rice dominates the agroecosystem. Glutinous rice is the staple food. More nonglutinous rice is grown for commercial purposes. - Upland cash crops: kenaf, cassava, sugarcane, rubber

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12 Village: Basic social unit of rural people.

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14 Categories trees found in paddy fields 1. Trees surviving from the forest: Most of these trees were once part of the dry dipterocarp forest. The most commonly found are in the family Dipterocarpaceae. 2. Domesticated trees: Those introduced into the system after paddies have been established.

15 Some forest survivors in upper paddy fields in Phu Wiang district of Khon Kaen.

16 A stand of Shorea obtusa (teng) in a paddy field in Kranuan district of Khon Kaen

17 Xylia xylocarpa (daeng)

18 Irvingia malayana (krabok)

19 Domesticated trees: Samanea saman (Raintree, Chamchuree, Cham Cha)

20 Mango (Mangifera indica)

21 Tamarind (makham) Tamarindus indicus

22 Phyllanthus polythyllus (Siaw)

23 Reasons for the existence of trees in paddy fields -Ecological reasons: Some species can survive the altered ecological conditions involved in paddy building and yearly rice cultivation. -Socio-economic reason is based on the farmers conscious decision to retain and/or plant some certain species.

24 Some forest tree species can survive the flooding regime of normal paddy rice cultivation.

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26 Uses of trees in paddy fields (socio-economic reasons)

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31 Coreya arborea (Kradon)

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33 Dipterocarpus intricatus (sabaeng)

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40 Combretum quadrangulare (sakae naa)

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44 Mitragyna javanica (krathum na)

45 Ecological roles of trees in paddy fields

46 Aboveground biomass Through fall Mineral transformation

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55 Farmers perception and knowledge of the effects of paddy field trees on soil and rice

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57 -Trees are good for soils but have negative effects on associated crops. -Positive effects of trees on the rice yields during dry years.

58 Concluding remarks: -As farmers in the Northeast penetrate more deeply into the cash economy, the diversity of their farming activities gradually decreases. Such is also happening to the trees-in-paddyfields agroecosystem. -However, a market-dependent life style constantly holds the risk of failure to small farmers, and it is, thus recommended that a certain degree of self-sufficiency is maintained. - Therefore, integration of more trees into ricepaddy would seem to be desirable.

59 Thank you

60 Fig. Crown Projection and Litter Trap Positions of Site A Fig. Profile Diagram Across the Plots of Site A Source: Vityakon et al. (1988)

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64 Seasonal distribution of litter fall in high and low density plot in Tree species: Dipterocarpus obtusifolius Quantity of liiter fall (g/sq. meter) High tree density Low tree density 0 J F M A M J J A S O N D Month Source: Vityakon (1998)

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66 Fig. Measurements of tree crown, and the three tree-soil transects along which soil and plant samples were collected

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70 Fig. Soil fertility (at 0-10 cm depth) of paddy soil at different distances from tree base Source: Sae-Lee et al. (1992)

71 Fig. Effects of different paddy-bund tree species on paddy soil fertility at 0-10 cm. soil depth. Source: Sae-Lee et al. (1992)

72 Fig. Effects of different paddy-bund tree species on rice grain yield and biomass production Source: Sae-Lee et al. (1992)

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90 Fig. Changes in relative remaining weights of various leaf litter during the decomposition (Small letters denote comparisons among various leaf litter at each sampling interval)\ Source: Adulprasertsuk et al. (1997)

91 Tab le Decomposition (k) and half life (t1/2) of leaf litter from various trees Tree name k t day - month - months D tuberculatus I malayana S saman S obtusa T indica X xylocarpa Source: Adulprasertsuk et al. (1997)

92 Table The E /E ratios of humic acid in soils affected by litter from various trees of different quality as shown by their lignin and decomposition rates (k). Tree name Dipterocarpus tuberculatus Samanea saman Tamarindus indica k (day - Lignin E /E ratios (g kg - of humic acid adapted from Adulprasertsuk et al. ))