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Poster Session 6
“The management of these agro-ecosystems”

Sandy soil improvement using organic matter and mineral fertilizers
on the yield and quality of papaya

Ta-Oun, M.1; S. Panchaban1; S. Pruangka 2 and P. Therajindakajorn1

Keywords: Sand soils, manures, mineral fertilizers, papaya fruit quality

Abstract

In an effort to improve the chemical and physical properties of a sandy soil from Northeast Thailand, a study was undertaken where varying rates of manure and mineral fertilizers were applied to growing papaya. The experiment was a fully randomized factorial design with 3 replications. Rates of manure, mineral fertilizer containing primary, secondary and trace elements and complete fertilizer were varied at rates of low, medium and high. It was found that secondary elements had more effect on the growth of papaya than trace elements. A complete fertilizer mixture is essential for increased yield. The highest rates of material concentration gave the highest yield of Kag nual variety than manure, primary elements, secondary elements and trace elements by the average of 3.89, 2.23, 3.62, 2.13 and 0.53 kg rai-1 respectively. The high rates of manure gave higher Vitamin C and sweetness both in row and ripen fruits which the values were closed to primary element fertilizer and complete fertilizer with the average range of 47-51 mg-ascorbic acid per 100 g fresh weight and 8.36-8.99% Brix which improved the papaya fruits quality resulting in more crunchy fruit with a better taste.


1 Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand.
2
Faculty of Science and Technology, Udonthani Rajabhat University, Udonthani 41000, Thailand.

Effect of various amendments on yield and quality of papaya grown
on sandy soils

Ta-Oun, M.1; S. Panchaban1; S. Pruangka2 and P. Therajindakajorn1

Keywords: Mineral fertilizers, manures, pumice, fruit quality, sandy soils

Abstract

To study sandy soil amendment material together with 13-13-21 mineral fertilizer for better stand and growth of Kag nual papaya variety, the experiment design was a factorial completely randomized blocks design with 3 replications. Five kinds of soil amendment material namely 1) manure 2) dolomite 3) phosphate rock 4) pumice and 5) pumice sulfate were applied at three rates. Results indicate that basal application of manure gave higher yield than dolomite, phosphate rock, pumice and pumice sulfate with average fresh fruit of 3.74, 2.16, 3.05, 1.78 and 1.49 t/rai respectively. Basal applications of manure at 3, 6 and 12 kg/hole gave the average fruit weight of 3.71, 3.71 and 3.81 t/rai respectively. The medium rate of dolomite, phosphate rock, pumice and pumice sulfate gave better results than lowest and highest rates with the average of 2.86, 3.05, 2.00 and 2.00 t/rai respectively. The application of dolomite and basal manure application tended to increase Vitamin C, sweetness, and electrical conductivity of raw fruits when compared to phosphate rock, pumice and pumice sulfate. This resulted in more crunchy and better tasting fruit.


1 Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand.
2
Faculty of Science and Technology, Udonthani Rajabhat University, Udonthani 41000, Thailand.

Vietnam-Belgium project for improving food crop productivity on the sandy
soils of the coastal zone in Central Vietnam

Tu, P.K.1; P.Q. Ha2; T.V. Minh1; B.H. Hien2; Lebailly Ph.3; E. Haubruge3;
H. Maraite4; C. Bragard4; B. Delvaux4; Cl.N. Chiang4 and J.E. Dufey4

Keywords: Integrated farming systems project, sandy soils, soilcarbon management

Abstract

Central Vietnam is composed of two contrasting topographic areas parallel to the coastline: mountains in the West and lowlands in the East where most of the population is concentrated. Sandy soils are largely dominant in the cultivated area in this narrow strip along the sea. Typical constraints of these soils are chemical infertility and acidity, excessive drainage capacity, low organic matter content, associated with particular climate limitations: heavy rain, floods and droughts during certain periods. Environmental conditions also favour pests and diseases. An integrated research approach is foreseen to improve yield and quality of crops and achieve sustainable development of farming systems including socio-economic aspects. To meet these objectives, knowing the natural limitations of sandy soils, the project is focused on the carbon cycle in the whole farming system (soil-plant-animal) aiming at the better placing a great value on organic matter than is currently the case. This includes not only existing organic sources within the farms (crop residues, animal faeces) but also possible exogenous sources such as aquatic plants from pounds and more especially from the great lagoon of Thua Thien Hue Province which encompasses some 22,000 ha. The research for optimal management of organic matter includes earthworms composting, a technique already tested in South Vietnam by partners of the project. Biotic constraints, i.e. pests and diseases, are also evaluated in order to suggest integrated control of pathogens and insects in the framework of global farming systems and the environment.

Socio-economic studies are conducted in parallel in all research activities in order to estimate expected improvement of households’ income from some reorientation of farming practices. In the first step of the project, a detailed survey was carried out among 145 households in villages from the 4 districts of the coastal area of the Thua Thien Hue Province. Existing practices and the socio-economic situation are evaluated and selected pilot farmers are involved in the research of optimal practices. Soil samples (300) and organic matter samples (95) were collected during this survey. The partners of the project (2004-2008) include the Hue University of Agriculture and Forestry, the National Institute for Soils and Fertilizers in Vietnam, the Faculty of Agricultural Sciences of Gembloux, and the Catholic University of Louvain in Belgium.


1 Hue University of Agriculture and Forestry, 102 – Phung Hung, Hue City, Vietnam.
2
National Institute for Soils and Fertilizers, Chem – Tu Liem, Hanoi, Vietnam.
3
Faculté Universitaire des Sciences Agronomiques de Gembloux, Passage des Déportés 2, 5030 Gembloux, Belgium
4
Université Catholique de Louvain, Faculté d’Ingénierie Biologique, Agronomique et Environnementale, Croix du Sud 2/10, 1348 Louvain-la-Neuve, Belgium.

Salinity control by farmers practices in sandy soil

Maeght, J.L.1; O. Grungerger 1; H.C.1; S. Sukchan2; C. Hartmann1 and W. Wiriyakinateekul2

Keywords: sandy soil, farmers practice, salinity, rice production, water ploughing, land levelling

Abstract

Northeast Thailand is an area where the population (near 20 million) is dependent on white rice production, for their livelihood. Rice is produced on low fertility sandy soils using traditional techniques within the context of significant socio-economic constraints. Rice production is generally low due to several constraints that are not entirely due to the farmer. The development of salinity is one of the environmental constraint that farmers face. Salinity often becomes evident as salt patches that appear as crusts during the dry season. In field studies it has been shown that a combination of flooding, puddling and drainage reduced the level of salinity by 50% (initial electrical conductivity >4 mS cm-1). With this decline in salinity rice is able to grow adequately in these patches. However, this positive effect is only temporary. Field measurements indicated that, salt plumes due to the positive pressure head of the saline groundwater forced saline waters to the surface. The saline patches were located on slight elevations within the field, suggesting that they become points of salt concentration associated with capillary rise as the paddy dries out. Through land levelling these high points would be eliminated and reduce the risk of salt concentrations. In addition, levelling the field surface would during flooding result in a more uniform depth of water above the saline patches. Levelling cannot stop the upward movement of saline water under pressure but it can alleviate the secondary salinisation due to surface evaporation when the soil dries out. This simple and easily adopted practice represents an effective method of managing salinity associated with groundwater rise in these lowland rice production systems.

Introduction

According to recent estimations, 6.5% of the earth’s surface is affected by problems of salinisation (Cheverry et al., 1998). This is also the case, in Northeast Thailand on soils that are of low fertility. In this region, approximately 17% of soils are affected by salinity (Arunin, 1984) and a further 108,000 km2, which is more than twice the size of Switzerland are potentially at risk from the same phenomenon. In Northeast Thailand, the main cause of the extent of salinisation is believed to be upland deforestation leading to a rise of the saline water table (Williamson et al., 1989). In some cases the salinisation causes saline patches to form, which can reach a diameter of 25 meters.

Salinisation of soil is of increasing importance to national stakeholders concerned with the conservation of their agricultural land (Kohyama K. and Subhasaram, 1993). A decrease in rice production yield due to the occurrence of these regional saline patches could have serious affects on this area’s ability to satisfy the rising food demands of its increasing population (Fukui, 1991. Kono, 1991). In addition, rice cropping forms an intricate part of Northeast Thai culture, well established and important in a socio-cultural and economic aspectsl (Formoso et al., 1977), for which a decreasing yield would have serious consequences. The majority of the local population produce glutinous rice intended for their own consumption. When the area is large enough, jasmine rice is also produced for commercial consumption (Berio, 2005). Pluvial monoculture of rice crops is the main source of agricultural income in this area.

The problems of salinisation have been studied for many years in this region of Thailand (Arunin, 1984; Mitsuchi et al., 1986; Yuvaniyama A. 2001). However, there are still unanswered questions on the dynamics of these saline patches, especially during the rainy season and the possibility of the farmer’s practices controlling their development. With this objective, ways of controlling the effects of these saline patches were studied, and in particular, the tillage practices used in preparing the soil, that includes levelling in the presence of standing water within the field. This practice has already been used in other contexts and on other soils, notably in Senegal (Hammecker and Maeght, 1999). It was then necessary to evaluate the duration of the effects of the resulting desalinisation on the next season’s crops when the soil would be submerged. Topographic readings and measures by penetrometer were made in order to better explain the processes of soil evolution.

Materials and methods

Study area

The experiments were conducted on plots in Pra Yuhn, near Khon Kaen, Northeast Thailand (16º21′12.744″ North and 102º36′29.8″ East). The region’s soils are very sandy (Mitsuchi et al., 1986; Yuvaniyami 2001) and also poor in nutritive elements (Ragland and Boonpuckake, 1988). The soil has a sandy loam texture (Grunberger, 2002), less than 10% clay content and low levels of organic matter (Table 1).

These utisols of the Roi Et series have low cation exchange capacity, less than 5 cmolc kg-1 of soil (Table 1). In the saline patches the exchangeable complex has a higher sodium content compared to outside the patch. The region has a tropical, Savannah climate with rainfall of 1,200 mm that fall pre­dominantly from May to October. Evaporation is higher than precipitation, except in the height of the rainy season from July to September (Bolomey, 2002). Soil is regularly saturated by solutions of NaCl as the water table rises and conductivity has an average value of 20 dS m-1 and pH of 5.82. The water table is near the soil surface at the end of the rainy season and draws down by two metres in the dry season.

The soil was cultivated using traditional implements whilst maintaining a sufficient water level so that the entire field surface was covered. The soil surface was levelled and once completed, the excess surface water was drained from the field.

Three sampling exsercises were undertaken using a grid made up of squares each measuring 2 m2 that covered the whole plot. The quantity of reference points gathered has enabled the results to be presented in map form. It has also been possible to describe the form of the saline patches seen at soil surface in a spatial context. The topsoil (0-20 cm) of soil were removed in a tube and then mixed. EC of the soil extract (1:5) was measured on each sample. Two hundred samples were collected over the three sampling dates. The first phase took place before working the soil, the second, just after drainage of surface water following cultivation and levelling. The third phase took place after rice was harvested. The first two phases of sampling will show the effect of desalinisation by cultivation of the soil under a shallow water layer and the third phase will give information as to the persistence of this desalinisation.

The levelling of the topsoil was made easier by using topographic references (with a precision of 1 cm) on the same grid system as the maps of salinity. Seven other maps were made of the topographic surface on other plots with saline patches in order to provide more information. Resistance measures were made using a hand penetrometer (Eijkelkamp), on several plots of the same area inside and outside the saline patches and at profiles from 0-80 cm. Each layer was tested five times for each profile 5 by 5 cm.

Results

The initial map of salinity, made on the plot prior to cultivation of the soil clearly showed the presence of saline patches covering 20% of the area (Figure 1).

Maximum EC values exceeded 4 ds m-1 at many points in the saline patch. The second map, made after the soil was worked resulted in a significant decline in EC with maximum values not exceeding more than 2 dS m-1. This was attributed to the diluting effect of the standing water and the subsequent draining of the field (Figure 2).

Table 1. Selected soil chemical and physical properties in and external to a salt patch

Depth (cm)

Interior of the salted spots

External of the salted spots

Sand
%

Silt
%

Clay
%
CEC
cmolc kg-1
pH
H2O

C
%

Sand
%

Silt
%

Clay
%
CEC
cmolc kg-1
pH
1:5

C
%

0-9 66 28 6 1.4 7.0 0.4 55 40 4 2.0 4.4 0.4
15-20 60 34 6 1.5 6.7 0.1 63 31 6 2.0 5.7 0.1
25-35 63 31 6 1.5 6.4 0.0 60 34 5 2.4 5.9 0.0
45-55 48 29 14 4.7 7.5 0.0 44 42 15 2.5 5.6 0.0
 

Mangement of Tropical Sandy Soil for Sustainable Agriculture

Figure 1. Map of electrical conductivity (EC) prior to land preparation

Mangement of Tropical Sandy Soil for Sustainable Agriculture

Figure 2. Distribution of saline patches after cultivation, puddling and subsequent draining of the field prior to rice establishment

The third map, made after the harvest of the rice crop clearly shows that the salinity has started to rise during the growing season reaching values of 2.6 dS m-1 (Figure 3).

These readings show that it has not been possible to maintain the positive effect of desalinisation during the four months of crop cycle where the soil surface is submerged under a surface layer of water that is maintained due to the presence of bunds. The rising saline water table increased salinity in the centre of the saline patch to a depth of 20 cm from soil surface, the depth from which the soil samples were collected.

The topographic map reveals that the saline patches are found on slight elevations within the field of around 5 cm compared to surrounding soil surface (Figure 4).

The results of the control readings for the topography of 8 other plots confirm that for this area, 100% of the highest salinity occurs on elevated soil (Figure 5).

Mangement of Tropical Sandy Soil for Sustainable Agriculture

Figure 3. Electrical conductivity measurements con­ducted at the time of the rice harvest

Mangement of Tropical Sandy Soil for Sustainable Agriculture

Figure 4. Topographic map of height differences within a field indicating the non-uniform levelling achieved

Mangement of Tropical Sandy Soil for Sustainable Agriculture

Figure 5. Differences between the average height of saline patches when compared to non-saline areas in each of 8 fields sampled

The soils in the study plot typically show a layer of compact, resistant soil between -40 and -70 cm from surface. However, resistance measurements by penetration at the centre of the saline patches have shown that this resistant layer is absent (Figure 6). These results show an important difference in layer structure between the soil profile inside and outside the patch. This raises many questions as to the role of this compact layer and suggests the need for further research to understand the reasons for this modification in the profile which normally appears to be homogenous.

Mangement of Tropical Sandy Soil for Sustainable Agriculture

Figure 6. Penetrometer resistance measurements on soil profile inside and outside saline patch

Conclusion

This study has shown that it is possible to temporarily reduce the salinity associated with saline patches using simple farming techniques to work the soil. This desalinisation is altered by the rise of the saline water table towards the soil surface during the period of submersion. Salinity was however, found to be lower to that measured at the beginning of the field’s crop cycle. This technique therefore enables at least temporarily more favourable growing conditions by reducing salinity by 50% in the elevated centre of the patch. This reduction even though temporary, also helps to prevent an eventual build up of salinity over the seasons.

The levelling out of the soil to reduce topographic differences between the elevated saline patch, and the rest of the field also has beneficial effects. The surface water could be maintained more evenly over the field’s entire surface, helping to dilute salinity from the rising saline water table during submersion. The levelling of the sureface also helped to slow down the eventual formation of a drawing-up action on the higher parts of saline patches, sticking out from the surface during the dry season.

These simple methods of working the soil whilst submerged, levelling the surface and then draining off of the excess standing water can improve soil conditions for rice production. Easily implemented by farmers, these techniques are valuable in the control of soil salinity.

References

Arunin S., 1984 – Characteristics and management of salt-affected soils in the Northeast of Thailand. Ecology and management of problem soils in asia. 336.

Bolomey S., 2002 – The seasonal dynamics of salinity in a small rainfed rice-cropped watershed in Northeast Thailand (Isan).engineer report, 61, multigr.

Cheverry C. and Bourrié G., 1998 – La salinisation des sols. Sol interface fragile. 109-126.

Eijkelkamp, Agrisearch Equipment; http://www.eijkelkamp. com

Fukui H., 1991 – The rice/population balance in a Northeast Thai Village. Nº4, 28, 68-84.

Formoso B., 1997 – Ban Amphawan et Ban Han, Le devenir de deux villages rizicoles du Nord-Est thaïlandais. (eds. CNRS éditions), I, 754.

Grunberger O., 2002 – Visite du chantier de UR 067 Thaïlande.Supports d’illustrations, 24, multigr.

Hammecker C., Maeght J.L., Wade M., 1999. Essai de drainage sur le périmètre de Donaye 8 – Sénégal report multig.

Kohyama K. and Subhasaram, 1993 – Salt-afected doils in Northeast Thailand their salinisation and amelioration. Agricultural Development Research Center. Japan International Cooperation Agency, 60 p multigr.

Kono Y., 1991 – Rainfed rice culture and population growth. nº4, Southeast Asian Studies, 28, 56-67.

Maeght J.L. & al, 2005 – Salinity control by farmers practices in sandy soil. Tropical sandy soils Proceedings, Khon Kaen, Thailand. November 2005, on press.

Mitsuchi M., Wichaidit P. and Jeungnijnirund S. , 1986 – Outline of soils of the Northeast Plateau, Thailand. Their characteristics and constraints, ADR, Khon Kean, Thailand, pp. 64.

Williamson D.R., Peck A.J., J.V.T. and S.A., 1989 – Grounwater hydrology and salinisation in a valley in Northeast Thailand. IAHS.

Yuvaniyama A. 2001 – Managing problem soils in Northeast Thailand. In natural resource management issues in the Korat basin of Northeast Thailand: an overview, edited by. Kam S.P., Hoanh C.T., Trébuil G., Hardy B., IRRI, Limited Proceedings nº7, 147-156.


1 Land Development Department, Office of Science for Land Development/IRD, Phaholyothin Road, Chatuchak, Bangkok 10900, Thailand. E-mail Address: maeght@ird.fr
2 Land Department Development, Office of Science for Land Development, Phaholyothin Road, Chatuchak, Bangkok 10900, Thailand.

Land degradation assessment in drylands: are there management solutions?

Niino, Y.1

Keywords: Land degradation, assessment tools

Abstract

The project on land degradation assessment in drylands (LADA) is the official tool of the UNCCD and the GEF to develop a standard assessment methodology. LADA generates up-to-date ecological, social, and economic and technical information, including a combination of traditional knowledge and modern science, to guide integrated and cross-sectoral planning and management in drylands. LADA is developing tools and methods to assess and quantify the nature, extent, severity and impacts of land degradation, watersheds and river basins, carbon storage and biological diversity at a range of spatial and temporal scales. It is also building the national, regional and international capacity to analyse, design, plan and implement interventions to mitigate land degradation and establish sustainable land use and management practices.

LADA is to assess the regional and global baseline condition of land degradation with the view to highlighting the areas at greatest risk (hot spots). These assessments are supplemented by detailed local assessments that focus on root cause analysis of land degradation and on local (traditional and adapted) technologies for the mitigation of land degradation. Areas where land degradation is well controlled are included in the analysis.

LADA develops, with country participation, a framework for land degradation assessment at global and national levels through a consensus building process for which the long-term purpose is to identify socio-economic environmental benefits accruing from addressing land degradation in drylands in terms of conservation of biodiversity and international waters, and sequestration of carbon.


1 FAO Regional Office for Asia and the Pacific, Bangkok, Thailand.

Phosphorus index for tropical sandy rice field and pineapple fields

Sukreeyapongse, O.1; C. Charanworapan1; A. Pongkanjana1 and K. Kanjanathanaset1

Keywords: Phosphorus index, pineapples, sandy soils

Abstract

Sandy soils are typically infertile and required significant amounts of fertilizer to maintain their productivity. Both chemical fertilizer and organic fertilizer such as manures or composts not only provide important nutrients to the growing plant but are also subject to fixation by the soils, surface runoff and leaching into the groundwater. Phosphorus is one of the major factors influencing the development of algal and microorganism bloom in water bodies. Phosphorus concentrations in the soil, the rate and method of phosphorus application, soil erosion and water runoff are used as factors in the calculation of a phosphorus index (PI). Paddy sandy soil from Surin Province that typically represented a lowland area and a sandy soil from an upland pineapple production system from Prajuab-kirikan Province were used in this study. PI values calculated were 16.5 and 10 respectively. These values are rather low and indicate that these soils have a low potential in losing phosphorus. PI is an easily procedure to estimate phosphorus lost and surface wastewater risk assessment. Factors that influence PI and the methods of reducing PI were discussed.


1 Land Development Department, Chatuchak, Bangkok 10900, Thailand.

The potential of Quartzipsamments for sugarcane growing in Southeast Coast, Thailand

Tawornpruek, S.1; A. Suddhiprakarn 1 and I. Kheoruenromne1

Keywords: Sugarcane production, light textured soils, chemical and physical properties, suitability assessment

Abstract

A study on the potential of Quartzipsamments to support the growing of sugarcane on the Southeast Coast, Thailand was undertaken on four representative soil areas. The methodology used in this study included pedon analysis of soils in the selected areas, laboratory analyses of their physico-chemical properties, mineralogy, micromorphological characteristics and assessment of their properties related to sugarcane crop requirements.

Results of the study revealed that these soils are Quartzipsamments deposited on the coastal plain. They are deep soils developed mainly on local alluvium and wash deposits derived from granite. Their micromorphological characteristics show subangular to subrounded quartz grains as the major fabric component. Their texture ranges from sand to loamy sand and their bulk density ranges from moderately low to high (1.40-1.82 Mg m-3). Chemical analysis of soils indicates that they have a strong acid to neutral reaction (pH 5.1-6.8). They have very low to low organic matter contents (0.2-9.4 g kg-1), very low total nitrogen (0.01-0.03 g kg-1), very low to high available phosphorus (1-95 mg kg-1) and very low to low available potassium (1.5-46.8 mg kg-1). The soils have very low to medium cation exchange capacity (2-11 cmolc kg-1). Their base saturation percentage varies widely from 4-77%. Their electrical conductivity ranges from 0.1-1.9 dS m-1 indicating no salt effect.

Fertility assessment results indicate that most of these sugarcane-growing soils have low fertility except for a single area where the soil has a moderate fertility status. Their potential based on suitability assessment indicates that most of them are moderately suited but one profile is not suited for sugarcane growing because of its sandy texture and strongly acid condition. A recommended approach to increase their potential for sugarcane growing includes an emphasis on soil organic matter conservation and a more intensive soil-fertilizer management. A continuing effort on soil-fertilizer management is clearly needed to maintain effectiveness in sugarcane growing on these soils.


1 Department of Soil Science, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand.

Properties of coarse-textured Alfisols under cassava in Thailand

Thanachit, S.1; A. Suddhiprakarn1; I. Kheoruenromne1 and R.J. Gilkes2

Keywords: Alfisols, chemical characteristics, kaolin, cassava production

Abstract

Two Haplustalfs and one Paleustalf under cassava in Khon Kean Province, Thailand were selected for this study with the objective of assessing the relationship between spatial difference of soils, their use suitability and environment. These soils developed on washed deposits over local alluvium derived from clastic sedimentary rocks. Methods of the study included morphological analysis of soils in the field, laboratory chemical and mineralogical analyses of soil samples according to standard methods.

Results from the study revealed that all soils are deep and well developed with Ap-E-Bt-2C profile type. Their textures range from loamy sand to sandy loam. Dominant chemical characteristics include acidic condition (pH 4.6-6.9), low plant nutrient status and low organic matter content (0.63-3.73 g kg-1), low extractable bases (0.05-2.14, 0.03-1.94 and 0.02-0.28 cmol kg-1 for Ca, Mg and K) and low cation exchange capacity (0.10-5.81 cmol kg-1). Kaolin is the major constituent in the clay fraction with quartz dominating the silt and sand fractions. These two minerals reflect the low fertility status of these soils. As evidence of pits on quartz sand grains would indicate strong chemical weathering conditions. Concentrations of heavy metals (Cr, Co, Ni, Cu, As, Pb) illustrate little variation within all soil profiles. However, most of these element concentrations are not high enough to pose environmental hazard. For economic crop production, cassava is the most suitable crop for these soils. A recommended approach to increase the potential of these soils for other crops, include a more intensive soil-fertilizer management along with soil and root zone moisture conservation practices.


1 Department of Soil Science, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand.
2 School of Earth and Geographical Sciences, Faculty of Natural and Agricultural Science, University of Western Australia, Crawley, Australia.

Effect of land use management on groundwater and soil salinization in
Northeast Thailand

Yuvaniyama, A.1; R. Lertsirivorakul2 and V. Sriboonruang2

Abstract

Distribution of secondary salinization in Northeast Thailand is mainly caused by man-made. This paper deals with the effect of land use management in recharge area on saline groundwater to reduce soil salinization in discharge area.

There is about 2.8 million ha of saline soils or 17% of the total area of Northeast Thailand. The soils are classified as severe, moderate and slight saline areas of 240,000, 590,000 and 2,020,000 ha, respectively, and another estimated 3,140,000 ha of recharge area. Rock salt of the Mahasarakham Formation beneath the soil is the cause of soil and water salinization in the region. Human mismanagement affects water imbalance that causes secondary salinization through deforestation, salt making, reservoir construction and improper water management. Reforestation of neems (Azadirachta indica) and eucalyptus (Eucalyptus camaldulensis) is recommended for planting in recharge areas to decrease saline groundwater in discharge area. But it is difficult to follow because mainly present land use of the recharge area has already been changed to cassava plantation.

Effect of eucalyptus plantation and management in cassava plantation on saline groundwater level has been carried out at Nakhon Ratchasima Province in 2005. The results show obvious confirmation to be one of the recommendations for management in recharge area to reduce salinizaton in discharge area.


1 Land Development Department, Bangkok 10900, Thailand.
2 Khon Kaen University, Khon Kaen, Thailand.

Characteristic and management of tin mine tailings in Thailand

Srithongchim, S.1 and A. Tepsuporngul1

Abstract

Soil characteristics of tin mine tailings are generally of low fertility and have unfavourable physical conditions for supporting plant growth resulting this being due to disturbance during the tin mining operation. Management of the tailings for further use may be dependent upon ownership of the tailings land. Attempts to utilize the tailings for agricultural use through experiments and trials have been undertaken by the Office of Research and Development for land management among others. This includes the planting of forest tree species, growing of agricultural crops, improvement of the soil by several methods to elevate the fertility status and create more favourable conditions for plant growth. Successful methods consist of chemical fertilizer either used directly or by mixing with manure and other materials that are likely to improve the physical properties of tailings and ameliorate toxic conditions. There is still no large-scale application of the research findings due to the difficulties in initial improvement of the topographic condition of the tailings and the economic situation of the owner.


1 Land Development Department, Chatuchak, Bangkok 10900, Thailand.

The improved presences of Halophilic bacteria in sandy saline soils with the
application of chemical fertilizer, bioextract and molasses

Choruk, K.1

Keyword: Halophilic bacteria, saline soil, bioextract, chemical fertilizer, molasses

Abstract

The influence of Halophilic bacteria in enhancing saline soil was assessed after the application of chemical fertilizer, bioextract and molasses. Saline soils were sampled from the area of an old salt farm, Baan Nongwang, Kantarawichai District, Mahasarakham Province, Thailand. Soil textural composition was classified as a sandy loam with 79% sand. The sampled soils were transferred to pots without disturbing soil structure, simultaneously, chemical fertilizer, bioextract or molasses was added. The analysis included physical and chemical properties of the improved saline soils after 0, 14, 28 and 42 days of the additions.

The results revealed that the soils initial electrical conductivity (EC) was 7.13 mS/cm which was considered as moderately saline and limited plant growth. The number of Halophilic bacteria prior to the improvement was 7.346 Log CFU/g soil. After the addition of bioextract or molasses, there was a significant decline in EC, this being greatest on soils that had been treated with bioextract where the EC decreased to 4.44 mS/cm, followed by the soil improved with molasses; the EC reduced to 4.73 mS/cm. In addition, Halophilic bacteria populations were found to decline in those soils that had been treated with bioextract to a value of 6.753 Log CFU/g soil and for molasses treated soil to 6.667 Log CFU/g soil. Soil organic matter increased through the addition of either bioextract or molasses. Contrasting this, saline soil improved with a chemical fertilizer, the number of Halophilic bacteria increased at the highest (7.575 Log CFU/g soil) compared to those improved with bioextract or molass. Optimal salinity and pH introduced suitable conditions for Halophilic bacteria where the chemical fertilizer was applied to saline soil. To improve sandy saline soils, the addition of bioextract or molasses is recommended as these treatments reduce the EC of soils and enhance the populations of Halophilic bacteria compared to those of chemical fertilizer application.


1 Division of Environmental Technology, Faculty of Technology, Mahasarakham University, Mahasarakham 45000, Thailand.

Saline soil improvement with biofertilizer for the growing kale
(Brassica Albonglabra)

Kurukodt, J.1

Keywords: Sandy soil, biofertiliser, kale, saline soil improvement

Abstract

Sandy saline soil occupied large areas of Northeastern Thailand and is considered as one of the most significant soil degradational and environmental problems facing the region. Associated with this problem is decline soil fertility. In the current study improving the soil fertility through the use of biofertilizer was assessed. Biofertilizer was applied at the following rates; 0, 5:1, 5:3 and 5:5 (soil: biofertilizer). The soil collected from the Chiang Yun District, Mahasarakham Province, Thailand was highly saline with and EC of 9.86 dS/m and was used in the pot experiment. Soil properties including major nutrients; N, P and K, EC, pH were determined prior to and at the termination of the pot experiments. The growth of Kale was determined 45 days after establishment. The application of biofertilizer at the ratio of 5:5 showed optimal soil improvement with a reduction in soil EC to 1.59 dS/m and incremental increases in N, P and K. Highest Kale growth and production were also observed at this rate. The role of Biofertilizer in the rehabilitation of sandy saline soils was demonstrated.


1 Faculty of Technology, Mahasarakham University, Mahasarakham 45000, Thailand

Organic agricultural systems for cassava crops in soil group 40

Junrungreung, S.1; S. Chinon1; T. Rattanakaew1 and S. Saelim1

Keywords: Green manures, sandy soils, cassava

Abstract

A study was carried out on Soil Goup 40 during 2003-2005 at Amphoe Jombung Ratchaburi Province where the soil is classified as a sandy loam with a low inherent fertility. The design of the trial comprised of a completely randomized block design with 10 treatments with 3 replications which were as follows; control, conventional method, the combination of using of Canavalia sp as green manure and mulching with Vigna sp Crotolaria sp as green manure, mulching with Vigna sp and Canavalia sp as green manure and mulching with Vigna sp. The another 4 treatments were Canavalia sp and Crotolaria sp as green manures and mulching with Vigna sp incorporated with liquid fertilizer, Crotolaria sp and Vigna sp as green manure mulching with Canavalia sp incorporated with liquid fertilizer. There was a tendency for those treatments comprising of green manure incorporate with mulching and liquid fertilizer having greater height, yield and starch of cassava than those treatments receiving just the green manure incorporated with mulching or conventional method. The height, yield and starch of cassava in these treatments were in the range 22.78-30.23 ton/ha, 127.2-141.3 cm and 12.2-14.9% respectively. Moreover, it was found that the combination of Crotolaria sp. incorporated with Canavalia sp and liquid fertilizer resulted in the highest, yields and starch. An assessment of the economic return on investments indicated that the combination of Crotolaria sp. incorporated with Canavina sp and liquid fertilizer gave the greatest net profit.


1 Institute of Research and Development for Soil Biotechnology, Land Development Department Ministry of Agriculture and Cooperatives, Bangkok 10900, Thailand.

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