357-5 Growth and Micro Nutrient Nutrition of Cacao Influenced by Source of Iron.



Wednesday, October 19, 2011: 9:05 AM
Henry Gonzalez Convention Center, Room 216A, Concourse Level

Virupax Baligar, USDA-ARS- Beltsville Agricultural Center, USDA-ARS, Beltsville, MD, Richard Sicher, Beltsville Agricultural Center, USDA-ARS, Beltsville, MD, Zhenli He, University of Florida, Fort Pierce, FL, Nand Fageria, EMBRAPA National Rice and Bean Center, Santo Antonio de Goias, Brazil, Jose Olimpio De Souza, UESC, Ilheus, BAHIA, Brazil and Dario Ahnert, UESC, Ilheus, BHAHIA, Brazil
Productivity and sustainability of cacao (Theobroma cacao L.) in tropical soils is affected by the availability of micronutrients in the soil.  Deficiency of iron (Fe) in soil pose a major growth limiting factor for cacao in highly weathered, coarse textured and leached soils..  Different forms of Fe fertilizers have been developed to improve Fe availability to plants in various types of soils. Information is lacking on the cacao response to various source of Fe.  A greenhouse experiment was conducted to evaluate the effects of five iron sources (FeSO4∙7H2O, FeEDDHA, FeDTPA, FeEDTA, FeHEDTA) at 10 mg Fe/kg soil mix on growth and micro nutrient nutrition of cacao.  Iron sources had significant effects on biomass accumulation of leaf, shoot and  root , leaf area, content of chlorophyll a and b, carotenoid , and SPAD values.  Total biomass accumulations and leaf areas were highest with FeEDTA and lowest with FeSO4.  Concentrations of chlorophyll a and b  and carotenoids were highest with FeDTPA and lowest with FeSO4.   Iron sources also had significant effect on  shoot concentrations of Cu, Fe, Mn, and Zn  but had no effect on the concentrations of B.  The concentrations of Cu and Fe were highest with FeHEDTA  and FeEDTA respectively and lowest with FeSO4..  However, the concentrations of Mn,  and Zn were highest with FeDTPA and lowest with FeHEDTA.  Overall Fe concentrations were positively correlated with B (r=0.92**) and Cu ((r=0.35 NS), however  they were negatively correlated with Mn (r=-0.60**) and Zn (r=-0.46*).  Overall addition of Fe chelates to soil improved Fe supply and resulted in decrease  shoot concentrations of Mn, and Zn
See more from this Division: S04 Soil Fertility & Plant Nutrition
See more from this Session: General Soil Fertility and Plant Nutrition: I