Assessment of Influence and Inter-Relationships of Soil Properties in Irrigated Rice Fields of Bangladesh by GIS and Factor Analysis

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 9 (2007): Assessment of Influence and Inter-Relationships of Soil Properties in Irrigated Rice Fields of Bangladesh by GIS and Factor Analysis. Manuscript LW 07 022. Vol. IX. November, 2007

Toxic Metals (Pb and Cd) and Their Respective Antagonists (Ca and Zn) in Infant Formulas and Milk Marketed in Brasilia, Brazil

In non-ideal scenarios involving partial or non-breastfeeding, cow’s milk-based dairy products are mainstream in infant feeding. Therefore, it is important to study the concentrations of potentially neurotoxic contaminants (Pb and Cd) and their respective counteracting elements (Ca and Zn) in infant dairy products. Fifty-five brands of infant formulas and milk sold in Brasilia, Brazil were analyzed. The dairy products came from areas in the central-west (26%), southeast (29%) and south of Brazil (36%) extending as far as Argentina (7%) and the Netherlands (2%). For toxic Pb and Cd, median concentrations in powdered samples were 0.109 mg/kg and 0.033 mg/kg, respectively; in fluid samples median Pb concentration was 0.084 mg/kg, but median Cd concentration was below the limit of detection and overall values were below reference safety levels. However, 62% of these samples presented higher Pb concentration values than those established by FAO/WHO. Although the inverse correlation between Cd and Zn (Spearman r = −0.116; P = 0.590) was not statistically significant, the positive correlation between Ca and Pb was (Spearman r = 0.619; P < 0.0001). Additionally, there was a significant correlation between Pb and Cd. Furthermore, the study also revealed that provision of the essential trace element Zn in infant formulas can provide adequate amounts of the recommended daily requirements. Infant formulas and milk sold for consumption by infants and children can be an efficient tool to monitor neurotoxic metal risk exposure among young children

Iron deficiency in peanut on black calcareous soils

Black calcareous soils of Thailand (Rendzinas or Calciustolls) occupy 500 000 ha and are located mostly on the highlands of central and northern areas of the country. These soils are considered quite fertile, but leaf chlorosis resembling iron deficiency occurs quite commonly in peanuts, although patchy in distribution

Iron-deficiency specifically limits nodule development in peanut inoculated with Bradyrhizobium sp

Severely iron‐deficient peanuts (Arachis hypogaaea L.) grown on calcareous soils in central Thailand failed to nodulate until given foliar iron applications. Glasshouse experiments were conducted on two cultivars (Tainan 9 and Robut 33–1) to identify which stage of the nodule symbiosis was most sensitive to iron‐deficiency. Iron‐deficiency did not limit growth of soil or rhizosphere populations of peanut liradyrhizobium. Similar numbers of root nodule initials formed in the roots of both control and iron‐sprayed plants, showing that iron‐deficiency did not directly affect root infection and nodule initiation. Plants sprayed with iron produced greater numbers of excisable nodules and carried a greater nodule mass than untreated plants. Five days after iron application, nodules on sprayed plants of CV. Tainan 9 contained 200–fold higher bacteroid numbers per unit weight and 14–fold higher concentrations of leghaemoglobain. The onset of nitrogenase activity was also delayed by iron deficiency in both cultivars. Tainan 9 appeared more sensitive to iron‐deficiency than Robut 33‐1 in terms of nodule mass produced, but both cultivars showed the same effect of iron‐deficiency on nitrogenase activity per plant. It is concluded that the failure of the infecting rhizobia to obtain adequate amounts of iron from the plant results in arrested nodule development and a failure of nitrogen fixation

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

Iron nutrition of field crops in black calcareous soils of Thailand: A review

Iron (Fe) deficiency limits crop production on black calcareous soils (Typic Calciustolls) of Thailand with reports of Fe deficiency becoming more common. Much of the Fe in these soils occurs as free crystalline and amorphous Fe oxides and DTPA extractable Fe is low averaging 6. 4 mg/kg in 20 soils examined. Field studies showed that Fe deficiency could be alleviated by soil amendments such as elemental sulfur or by soil and foliar Fe fertilizer, provided rates of application were high enough. However, since soil amendment and Fe fertilizer use is costly, preliminary research into cultivar selection for Fe efficiency has begun with peanuts. Kernel yields in 20 cultivars were inversely related to Fe chlorosis scores. Standards for diagnosis and prediction of Fe deficiency in field crops are being developed for soil and plant analyses using DTPA and o‐phenanthroline, respectively