Mineral nutrition of food legumes in Thailand with particular reference to micronutrients

THE aims of the study were to determine the extent and severity of micronutrient deficiencies for the production of the food legume crops, black gram, green gram, peanut and soybean, in four regions of Thailand (north, northeast, central and southeast), and to develop procedures for their diagnosis, prediction and correction in farmers' crops. The importance of macronutrient deficiencies in legume crop production was also explored and procedures for their diagnosis developed. The study has shown that a high proportion of legume crops in Thailand suffer from one or more deficiencies of the micronutrients boron (B) and molybdenum (Mo) and the macronutrients phosphorus (P), potassium (K), sulfur (S), and nitrogen (N)

A generalized multiple regression model to predict cadmium uptake in rice grain

Paper presented at the 8th International Conference on the Bio-geochemistry of Trace Elements, Adelaide, Australia, 3-7 April 200

On-farm trials for molybdenum requirement of groundnut

Previous survey of Mo concentrations in young fully expanded leaves (YFEL) of farmers' groundnut crop in many areas of the Northeast and East Thailand revealed that many samples contain rather low Mo concentration, indicating that those areas may be deficient in Mo for groundnut. In 1988, field trails were conducted at 3 of the low Mo locations in the Northeast. Groundnut cultivar Tainan 9 were treated with 2 rates of Mo (0 and 500 g. Mo/ha) and supplied with complete fertilizers, i.e., P, K, Mg, S, Cu, Zn and B, at planting; supplementary gypsum was supplied at pegging. At flowering, adding Mo greatly increased shoot dry matter, N content and N concentration in YFEL and also increased Mo concentration in nodules, tops and YFEL. Molybdenum application increased seed yield of groundnut at Ban Had by 19 % but not at the remaining two sites, despite the fact that all had low levels of extractable Mo in the soils. These soils release sufficient Mo from adsorbed forms to satisfy the requirement of groundnut cultivar Tainan 9 for seed dry matter yiel

Analysis of field-moist Cd contaminated paddy soils during rice grain fill allows reliable prediction of grain Cd levels

Research undertaken over the last 40 years has confirmed that the long-term consumption of cadmium (Cd) contaminated rice contributes to human Cd disease. Rice is the staple of millions throughout South and Southeast Asia. Therefore, the ability to accurately assess the risk of rice grain Cd uptake in areas of elevated soil Cd would be a pre-requisite to protecting public health and regional export security. During 2001-2002, 308 concomitant soil and rice grain samples were collected from a Cd/Zn co-contaminated site in Western Thailand and determined for aqua regia digested soil Cd and rice grain Cd. No significant relationship was observed between total soil Cd and rice grain Cd (r 2 = 0.117). This intuitively is to be expected since total soil Cd bears no relationship to phyto-available Cd. Similarly no relationship was observed between 0.005 M DTPA extractable soil (air-dry) Cd and rice grain Cd (r 2 = 0.165). Again this result could have been predicted as the phyto-availability of Cd in paddy soils is a function of the complex interaction between soil pH, redox conditions and the presence of competing ions. Consequently, in 2003 a further study was undertaken to assess the effectiveness of commonly utilized soil extractants namely, 0.1, 0.05 and 0.01 M CaCl2 solutions at a soil extractant ratio of 1:5 and 1 M NH4NO3 for 2 h or 4 h extractions times at a soil/extractant ratio of 1:2.5. Soil samples were collected at the critical rice grain fill stage and sub-divided into Portion A which was subjected to conventional air-drying and sample preparation procedures and Portion B which was maintained at Field Condition (FC) and stored at <4 C until extractions were undertaken. Concomitant rice grain samples were collected at maturity. The results indicate that air-dried soil samples subjected to conventional soil preparation procedures were totally ineffective at predicting the uptake of Cd by rice stem, leaf or grain, regardless of extractant. Further, the results indicate that the Stepwise Regression model incorporating 0.1 M CaCl2 extractable Cd and soil pHw determined on field moist samples accounts for 63.8% of the variability in rice grain Cd

Impact of waste recycling on sustainable agriculture in Thailand

P. Pongsakul, W. Nobuntou, S. Attajarusit, M. J. McLaughlin, M. Warne and G. Cozenshttp://rnavi.ndl.go.jp/mokuji_html/000008034840.htm