Growth of Forage Legumes and Grasses in Acidic Soil Amended with Flue Gas Desulfurization Products

Large amounts of flue gas desulfurization products (FGDs) are produced when SO2 emissions are trapped in the coal burning process for generation of electricity. FGDs are normally discarded instead of being reused, and reuse on soils could be important in overall management of these products. Glasshouse experiments were conducted to determine effects of various levels of three FGDs (a FGD gypsum, an oxidized FGD + Mg, and a stabilized FGD) and the control compounds CaCO3, CaSO3, and CaSO4 on growth of alfalfa (Medicago sativa), white clover (Trifolium repens), orchardgrass (Dactylis glomerata), tall fescue (Festuca arundinacea), switchgrass (Panicum virgatum), and eastern gamagrass (Tripsacum dactyloides) in acidic (pH 4) soil (Typic Hapludult). The FGDs enhanced growth of each plant species, with alfalfa, white clover, and tall fescue receiving greater increases than the other species, especially when grown in soil amended with FGD + Mg. FGD gypsum did not often enhance growth unless high amounts were added. FGDs containing high B and low levels of CaSO3 were detrimental to growth. Overall, FGDs improved growth responses of these forage plants grown in an infertile low pH soil

Nutrição de ferro das plantas: química e fisiologia da sua deficiência e toxicidade

Iron deficiency and toxicity are important yield limiting factors in crop production around the world. In this review, an attempt is made to summarize the information on diagnosis of Fe deficiency and toxicity, chemistry of Fe in soil, mechanism of Fe uptake, role of chelates in Fe nutrition, factors affecting Fe availability to crop plants and measures required to correct Fe deficiency and toxicity. A brief discussion about Fe toxicity in flooded rice is also included. Information presented in this review article should provide a basis for correcting this nutritional disorder in crop plants, and indicates new research efforts needed to solve Fe stress problems.A deficiência e toxidez de Fe são fatores que limitam o rendimento das culturas. Nesta revisão é apresentado um resumo das informações sobre a diagnose da deficiência e toxidez química do Fe no solo, mecanismo de absorção, importância dos quelados de Fe na nutrição de plantas, fatores que afetam a disponibilidade de Fe e dos métodos de correção da deficiência e toxidez de Fe. É feita também uma discussão resumida sobre toxidez de Fe com arroz irrigado. Esta revisão fornece informações básicas para correção de desordens nutricionais que envolvem Fe, e sugere pesquisas a serem feitas visando solucionar problemas de estresse de Fe

The effects of aluminum on growth and uptake of Al and P by rice

Toxidez de alumínio é um fator importante, que limita o crescimento das plantas em solos ácidos. Foi estudado o efeito de cinco níveis de Al (0, 371, 742 1484 e 2226 μM) em solução nutritiva sobre o crescimento e absorção de Al e P pelas cultivares de arroz Suvale 1 e IRGA 408. O alumínio reduziu o crescimento das raízes e da parte aérea nas duas cultivares, mas a redução foi maior para a cultivar IRGA 408. A absorção de Al aumentou com o aumento de níveis de Al nas duas cultivares. O efeito foi maior nas raízes do que na parte aérea. A cultivar tolerante Suvale 1 absorve mais fósforo que a cultivar sensível IRGA 408. A absorção e a eficiência de utilização de P foram altamente correlacionadas com o crescimento das plantas. Os níveis tóxicos de Al em solução nutritiva foram de 260 μM para a parte aérea, e de 280 μM para as raízes.Aluminum toxicity is an important factor limiting plant growth in acid soils. The effect of five Al levels (0, 371, 742, 1484, and 2226 μM) in nutrient solution on the growth and uptake of Al and P by two rice cultivars (Suvale 1 and IRGA 408) was studied. Aluminum reduced root and shoot growth in both, cultivars, but the reduction was greater in IRGA 408. Aluminum uptake was increased with increasing levels of Al in the two cultivars. The effect was greater in the roots as compared to the shoots. The tolerant cultivar Suvale 1 absorbed more phosphorus to susceptible cultivar IRGA 408. The uptake and use efficiency of P was highly correlated with the growth of the rice plant. Toxic Ali level in the nutrient solution were 260 μM for shoot growth and 280 μM for root growth, respectively

Response of rice cultivars to phosphorus supply on an oxisol.

Genotypic differences in absorption or utilization of P might be exploited to improve efficiency of fertilizer use or to obtain higher productivity on P-deficient soils. The objective of this study was to evaluate responses by 75 genotypes of upland rice (Oryza sativa L.) to two soil P levels in two field experiments. In the first experiment, soil P levels (Mehlich 1) were 1.5 mg kg-1 and 5 mg kg-1, and in the second experiment, 3 mg kg-1 and 4.7 mg kg-1 of soil, respectively. Rice cultivars differed significantly in shoot dry matter production at flowering, grain yield, and plant P status. Based on a grain yield efficiency index, cultivars were classified as P-efficient or P-inefficient. Shoot dry matter was more sensitive to P-deficiency but was not related to grain yield. Phosphorus use efficiency was higher under the low P treatment. Phosphorus uptake was significantly correlated with dry matter, P concentration and P-efficiency ratio. Results of this study indicate that genetic differences in P-use efficiency exist among upland rice cultivars and may be exploited in breeding programs