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Assessment of cadmium and lead contamination in rice farming soils and rice (Oryza sativa L.) from Guayas province in Ecuador Texte intégral
2020
Ochoa, Martín | Tierra, Wladimir | Tupuna-Yerovi, Diego Santiago | Guanoluisa, Danilo | Otero, Xosé Luis | Ruales, Jenny
Rice is the world’s most consumed and in-demand grain. Ecuador is one of the main rice-consuming countries in Latin America, with an average per capita consumption of 53.2 kg per year. Rice cultivation takes place under flooding conditions, which favors the mobilization and subsequent accumulation of heavy metals in the plant. This study’s principal objective was to evaluate the contamination of cadmium (Cd) and lead (Pb) in the rice cultivation system in the province of Guayas. To this end, extensive sampling of water, soil and rice grains was carried. Water samples were analyzed to determine physicochemical properties and concentrations of dissolved Cd and Pb. Physicochemical properties, total organic carbon (TOC), total content of nitrogen (N), iron (Fe), manganese (Mn), phosphorus (P), bioavailable phosphorus (P mehlich), Cd and Pb were determined in soil samples. In addition, to understand the dynamics of Cd and Pb mobility and bioavailability, an extraction of six randomly selected soil samples was carried out. The concentration values of the total Cd and Pb content in the rice cultivation system did not exceed the maximum recommended limit for soil, water and rice grains. However, 85% of the total Cd was in the soluble or exchangeable fraction of the soil, while the Pb was strongly bound to crystalline iron oxyhydroxides. It was established that the TOC, N, Fe, and P mehlich have a significant correlation (p < 0.05) with the overall concentration of Cd and Pb in the rice farming soil. The Cd and Pb present in rice do not represent a dietary health risk to the population of Ecuador.
Afficher plus [+] Moins [-]Experimental work related to nitrogen deposition, nitrification and soil acidification - a case study
1988
Nilsson, S.I. | Berden, M. | Popovic, B. (Department of Ecology and Environmental Research, Swedish University of Agricultural Sciences, 750 07 Uppsala (Sweden))
Downward movement of cadmium and phosphorus from phosphatic fertilisers in a pasture soil in New Zealand
1997
Loganathan, P. | Hedley, M.J. (Fertilizer and Lime Research Centre, Massey University, Palmerston North (New Zealand))
The influence of mycorrhizal symbiosis and fertilizer amendments on establishment of vegetation in heavy metal mine spoil
1994
Hetrick, B.A.D. | Wilson, G.W.T. | Figge, D.A.H. (Department of Plant Pathology, State University, Manhattan, KS 66506 (USA))
Forms of cadmium in sandy soils after amendment with soils of higher fixing capacity
1995
Mann, S.S. | Ritchie, G.S.P. (Soil Science and Plant Nutrition, School of Agriculture, University of Western Australia, Nedlands, WA, 6009 (Australia))
Does (K+Mg+Ca+P) fertilization lead to recovery of tree health in a nitrogen stressed Quercus rubra L. stand?
1994
Boxman, A.W. | Cobben, P.L.W. | Roelofs, J.G.M. (Department of Ecology, Section of Environmental Ecology, University of Nijmegen, PO Box 9010, NL-6500 GL Nijmegen (Netherlands))
Mitigation of nutrient losses via surface runoff from rice cropping systems with alternate wetting and drying irrigation and site-specific nutrient management practices Texte intégral
2013
Liang, X.Q. | Chen, Y.X. | Nie, Z.Y. | Ye, Y.S. | Liu, J. | Tian, G.M. | Wang, G.H. | Tuong, T.P.
Mitigation of nutrient losses via surface runoff from rice cropping systems with alternate wetting and drying irrigation and site-specific nutrient management practices Texte intégral
2013
Liang, X.Q. | Chen, Y.X. | Nie, Z.Y. | Ye, Y.S. | Liu, J. | Tian, G.M. | Wang, G.H. | Tuong, T.P.
Mitigation of nutrient losses via surface runoff from rice cropping systems with alternate wetting and drying irrigation and site-specific nutrient management practices Texte intégral
2013
Liang, X. Q. | Chen, Y. X. | Nie, Z. Y. | Ye, Y. S. | Liu, J. | Tian, G. M. | Wang, G. H. | Tuong, T. P.
Resource-conserving irrigation and fertilizer management practices have been developed for rice systems which may help address water quality concerns by reducing N and P losses via surface runoff. Field experiments under three treatments, i.e., farmers' conventional practice (FCP), alternate wetting and drying (AWD), and AWD integrated with site-specific nutrient management (AWD + SSNM) were carried out during two rice seasons at two sites in the southwest Yangtze River delta region. Across site years, results indicated that under AWD irrigation (i.e., AWD and AWD + SSNM), water inputs were reduced by 13.4 ~ 27.5 % and surface runoff was reduced by 30.2 ~ 36.7 % compared to FCP. When AWD was implemented alone, total N and P loss masses via surface runoff were reduced by 23.3 ~ 30.4 % and 26.9 ~ 31.7 %, respectively, compared to FCP. However, nutrient concentrations of surface runoff did not decrease under AWD alone. Under AWD + SSNM, total N and P loss masses via surface runoff were reduced to a greater extent than AWD alone (39.4 ~ 47.6 % and 46.1 ~ 48.3 % compared to FCP, respectively), while fertilizer inputs and N surpluses significantly decreased and rice grain yields increased relative to FCP. Therefore, by more closely matching nutrient supply with crop demand and reducing both surface runoff and nutrient concentrations of surface runoff, our results demonstrate that integration of AWD and SSNM practices can mitigate N and P losses via surface runoff from rice fields while maintaining high yields.
Afficher plus [+] Moins [-]Phosphate-enhanced movement of arsenic out of lead arsenate-contaminated topsoil and through uncontaminated subsoil
1997
Peryea, F.J. (Washington State Univ., Wenatchee, WA (USA). Tree Fruit Research and Extension Center) | Kammereck, R.
